Military bridge training. General information about military bridges
Educational goal To form students' creative attitude to the choice of a bridge construction method. Learning objective 1. To give an idea of the technology and organization of the construction of military bridges and crossings. 2. To form knowledge of the organization of exploration of construction areas. 3. To instill skill in the organization of the PZMK. Type of lesson Practical lesson with a platoon. Venue VMP class, No. 6. Material support Posters, slides, study guide "Military bridges on rigid supports". Literature 1. Textbook "Military training of reserve officers of the road troops". Part II, pp. 112 -140 2. Textbook "Bridges and crossings on the VAD", pp. 114 -138.
The first question is “The composition of the region for the procurement of bridge structures. Timber harvesting technology” The second question is “Organization of a point for harvesting bridge structures, its purpose and composition, sorting logs and sawing timber at field sawmills” The third question is “A site for the manufacture of elements of low-water wooden bridges, piles, nozzles, blocks of girders, diagonal fights, elements of coastal supports and the roadway, production lines for the manufacture of blocks of wooden spans” The fourth question is “The delivery of structures of low-water bridges. Calculation of the need for vehicles”
The first question is “The composition of the region for the procurement of bridge structures. Timber harvesting technology” The area of harvesting of bridge structures includes: 1. logging site; 2. plots; 3. logging trails; 4. sorting yard; 5. cross-cutting platform; 6. loading area; 7. way of movement; 8. point of procurement of bridge structures. Harvesting of local timber, sawing logs, manufacturing of elements and blocks of bridge structures are carried out in the area of harvesting of bridge structures (RZMK), in which a cutting area is deployed and equipped (a site near a timber warehouse or a disassembled structure; transportation of timber and removal of finished bridge structures.Two types of logging can be used - selective and continuous.In military conditions, it is advisable to conduct harvesting selectively, but with homogeneous forests, it is more profitable to harvest by clearcutting.The units that harvest timber are equipped with
the necessary means of mechanization (motor saws, hydraulic wedges KGM 1 A, felling poles, axes, crowbars, wagons). The cutting area is divided into plots 70-80 m wide, and they, in turn, are divided into apiaries 17-20 m wide. The felling is carried out, if possible, along the existing clearings and roads. The felling direction of sawn trees depends on the type of skidding equipment that is planned to be used. With hydro wedge or felling pole
trees are felled at an angle of 30 ° to the portage. Trees in the portage strip are cut flush with the ground, and in the rest of the area, the height of the stumps is allowed to be no more than 30 cm. can reach 1 km, but in order to limit the idle runs of skidding means, the depth of development of the cutting area should not be increased. For felling, portable gasoline-powered saws and electric saws from sets of power plants are used. When selectively developing a forest, it is advisable to use gasoline-powered saws, and for continuous development, electric saws can also be used. Skidding of the forest is carried out by dragging using skidders, and other means that have sufficient power and maneuverability, depending on the terrain conditions, can also be used. For skidding the whips in the middle of each plot, apiary trails 5 m wide are laid, and from the plots to the crosscutting site, main trails 7–9 m wide. Log hauling is carried out by wagons (several whips) and consists of the following operations: the tractor moves to the place where the wagon is set; pulling away the traction steel rope and chokers (if there is no second set, then time is lost on this operation); chokering whips and collecting a cart with a winch; tractor move to the place of unloading and uncoupling of the cart.
Crosscutting and sorting of the whips are carried out on the crosscutting site, which is equipped with logs stacked with butts to each other, which makes it possible to have a slope from the butt to the top and facilitates the rolling of logs. Bucking is carried out in accordance with the drawn up schemes, which allows rational use of forest material. The bucking of the whips consists of the following operations: marking the whips along the length; cut the whips into logs; marking of logs (on their ends, in accordance with their purpose, letters are written: P runs, C piles, D boards, H nozzles, Cx fights, K wheel breaks, L bed); sorting of marked logs and their accounting. Templates are made for marking. Wooden calipers are used to measure the diameters of logs. Longitudinal sawing of timber is carried out on a saw frame LRV driven by a military diesel power plant ESD 50 VS. In addition, local stationary or temporary sawmills located in the area of work can be used. Productivity LRV 40 50 m 3 unedged boards and two-edged beams per shift (10 hours). For the production of carpentry, a carpenter's workplace is organized - a site with materials, tools, fixtures and finished products located on it, on which one or more people (calculation) perform the work assigned to them. It should be organized with the creation of the best conditions for successful and highly productive work. The mutual arrangement of materials and fixtures should also provide for the minimum movement of materials and blocks during operation.
The second question “The point of harvesting bridge structures, its purpose and composition, sorting logs and sawing timber at field sawmills” PZMK includes a sawmill for harvesting lumber, production lines for the manufacture of block structures of superstructures and work sites for the manufacture of elements of bridge structures. The sawmill, production lines and work sites are located as close as possible and are combined into a single technological stream. For the manufacture of superstructures from individual elements, a PZMK with one saw frame is deployed, and for the manufacture of span structures of a block type with three, two or one saw frame. In the event that the PZMK is equipped with sawmill frames for the manufacture of bridge structures with block spans, it may consist of: a sawmill; one, and with three sawmills, two production lines for the manufacture of block structures of superstructures; work sites for cutting boards, making roadway shields, piles, frame and cage supports. As a rule, contractions, nozzles and wheel breaks are made at sites for the manufacture of superstructures. First of all, nozzles and contractions are made, and then structures of superstructures are made. Wheel breakers are made last. Work on the production of elements on the sites is carried out in parallel. In the manufacture of bridge structures with spans from individual elements, the PZMK includes a sawmill and work sites for the manufacture of nozzles, girders, piles, frame and cage supports.
If necessary, non-standard PZMK can be deployed for the manufacture of structural elements of the bridge. In this case, some changes are made to ensure the most rational use of the available means of mechanization and the personnel involved in these specific conditions. In the case when 4 or 6 sawmill frames are used, it is necessary to enlarge the sites accordingly (increase the size and equip with additional mechanization means) for the manufacture of piles, frame and cage supports. In this case, it would be advisable to deploy an additional platform for the manufacture of nozzles, support bouts, using one of the sawmill frames specially for this. A typical PZMK with three sawmill frames for the manufacture of bridge structures with block spans is deployed when there are necessary conditions for this (forces, means, scope of work, etc.)
A typical PZMK with one saw frame for the manufacture of bridge structures with block spans has a somewhat simplified scheme. 1. - the way of timber transportation; 2. - place for the manufacture of piles and frame supports; 3. - sawmill frames; 4. - a place for cutting and storing boards and manufacturing embedded shields (flooring shields); 5. - production line; 6. - a place for storing structures; 7. - the way of export of structures; I - sawmill; II - working platform; III - platform for the manufacture of nozzles, beds, elements of the entry device.
In the manufacture of bridge structures with spans from individual elements, a typical PZMK with one saw frame can be deployed 1. a way for transporting timber; 2. cross-cutting platform; 3. sawmill frame; 4. the way of export of finished structures; I. working platform for the manufacture of piles and frame supports; II. working platform for the manufacture of wheel breaking runs; III. sawmill; IV. working platform for the manufacture of nozzles, beds of elements of entry devices.
The third question is “A site for the manufacture of elements of low-water wooden bridges, piles, nozzles, blocks of girders, diagonal scrambles, elements of coastal supports and a roadway, production lines for the manufacture of blocks of wooden spans” The site for the manufacture of elements includes: flooring, boards of protective flooring, wheel baffles); place of manufacture of scrambles of supports and blocks of superstructures; place of manufacture of structures (blocks of purlins and boards of the roadway); place of manufacture of frame supports (racks, nozzles, beds, lining shields); place of manufacturing elements of the entrance to the bridge piles of the fence wall, boards of the fence wall, boards for the entrance shield, thrust logs, lining logs, gouges.
When the construction of the bridge is planned to be carried out sequentially, starting from the coastal spans, it is more convenient to place the elements of the supports on the shore, and the elements of the span structures (for example, girders, crossbars, decking and railings) along the road. This arrangement shortens the path for supplying elements to their installation site. Piles are made by hand or using a pile harvesting machine (SZS). In the manufacture of piles, a rack is manually equipped, which is two slabs laid on transverse logs or beams, which, in turn, are laid on linings. The elements of such a rack are fastened with pins. The height of the rack is 60-70 cm, the length is 9-11 m. Cuts are made in the logs for a fixed, stable position of the logs during their processing. The pile head is machined into a cylinder. For processing, the pile is placed in the nests cut out in the slabs and markings are made according to the templates available in the sets of diesel hammers. The pile head is processed using a special chisel, its use allows you to remove wood in one go on a quarter of the circumference. Pre-cuts are made along the circumference of the pile, which facilitates processing. When processing the pile head, it is necessary to ensure the alignment of the head and the entire pile. The end surface is machined perpendicular to the pile axis.
The end of the pile is made with four faces. First, on both sides, to a length equal to 2 2.5 diameters, the logs are hewn so that the tip of the pile is on its axis. Then the pile is rotated 180 ° and the other two sides are sewn. When hewing, the wood of the tip is cut, which facilitates the work and protects the pile from excess wood felling. The sharp end of the pile to a length equal to 1/3 of its diameter is cut off and then processed in the form of a quadrangular pyramid with a height equal to 1/6 of the pile diameter. The manufacture of nozzles and bed supports is carried out on a working platform equipped with horizontal beds. Heads of pile supports, as well as heads and beds of frame supports are made of logs, the diameter of which is 2 cm larger than the diameter of piles (racks). On the sleds, places are provided for storing logs (blanks), making nozzles and beds, as well as for storing finished elements. Double-edged bars from the place of storage are fed to the place of manufacture. Then, the length and position of the holes for the pins are marked according to the template. The template is made from a cut board with a section of 2.5 x15 cm and a length equal to the length of the nozzle or bed. After marking the timber, one calculation number with an electric saw saws off the ends, and the second one drills 3 holes. Manufactured nozzle (bed) is moved along the slopes to the place of storage. Full assembly of frame supports is carried out at PZMK only if the height of the supports allows them to be transported in finished form and there are accurate data on the water depth at the location of the support on the barrier. With a high height of the supports, when their transportation in assembled form is impossible, the pre-assembly of the frame supports is carried out at the PZMK with fitting of the elements and their marking.
The fourth question is “Transportation of structures of low-water bridges. Calculation of the need for vehicles” Transportation of bridge structures with PMMC to the bridge construction site is carried out by cars, and in some cases by helicopters. For the transportation of bridge structures, any vehicles with a carrying capacity of at least 2.5-3 tons are used without additional equipment or with the simplest equipment manufactured by the bridge-building department. The length of blocks or elements of bridges transported on cargo platforms of vehicles of the ZIL 131 type should not exceed 5.5 m, and when transported on vehicles of the Kr. AZ 6.5 m. Elements and blocks of bridges with a length of 5.5 to 6.5 m can be transported on vehicles of the ZIL 131 type, equipped with trestles, which make it possible to place elements of bridge structures with an overhang of the front ends above the vehicle cab. For the transportation of elements and blocks with a length of more than 6.5 m, cars with trailers with dissolutions are used. This method of transportation is the most preferable, since the trailer increases the carrying capacity of the car, the amount of cargo transported in one trip of the car increases. When transporting track blocks on vehicles of the ZIL 131 type, two track blocks are laid one on top of the other on a cargo platform. On the blocks, they are laid in advance and attached with mounting nails, one mortgage and inter-gauge shield each. Span structures from blocks of purlins up to 5 m long and roadway shields
are placed on the vehicle platform in the following order: first, the boards of the roadway are laid one on top of the other, and the run blocks are placed on top. Depending on the carrying capacity of the vehicles used for transportation, from 4 to 6 sets of pile support elements are loaded per vehicle. In this case, the following procedure for laying elements on a car without a trailer is accepted. In the bottom row there are shorter piles, and longer ones on them; nozzles and diagonal contractions are laid on top of the piles. When transporting support elements on vehicles with trailers, longer piles are placed in the bottom row, and shorter piles are placed on top of the piles, nozzles and scrambles are laid on top of the piles above the vehicle platform. Blocks and elements of bridges are loaded onto vehicles and unloaded from vehicles using truck cranes, cargo booms mounted on vehicles with winches, and other lifting equipment. For loading and unloading of individual elements, they are combined into packages, and each package must consist of elements of the same name (runs or floorboards). The number of elements in the package is determined by the carrying capacity of the lifting equipment used. When loading and unloading blocks and packages with a truck crane or an arrow mounted on a car, special gripping cable devices "spiders" are used. The gripping rope device consists of 2 or 4 pieces of rope with 4 hooks at the ends; all segments of the cables with the other end are attached to one end. The cable grip "spider" is put on the hook of the crane (boom), and the free ends of the cables are fixed to blocks or packages of elements. To fix the hooks of the "spider" on the blocks, special loops (brackets) are arranged or the cables are slipped onto the free ends of the runs. When transporting blocks and individual runs, having a length of more than 6.5 m, cars with single-axle or two-axle trailers are used. Single axle trailers
ensure the transportation of elements up to 10-12 m and a total weight of up to 6-8 tons. Two-axle trailers allow the transport of elements up to 14-15 m long and with a total weight of up to 15 tons. car. In order to successfully, in the shortest possible time to carry out the construction of the bridge, it is necessary to carefully consider the organization of work, that is, to determine in what way the work should be carried out within the specified time. The success of the construction as a whole will depend on how well the organization of work is thought out. For the proper organization of work, it is necessary to determine the need for people, building materials, transport, equipment and mechanisms; the calculation of the indicated forces and means is carried out on the basis of the technical project. In cases where the technical design has not yet been drawn up, calculations can be made approximately according to enlarged meters (for example, per 1 linear meter of the bridge), knowing the approximate size and nature of the structure and using the normative data of directories or special tables. The required number of people, building materials, mechanisms and equipment with known volumes of work can also be determined from the collections of the Uniform Performance Standards for Bridge Construction Works.
Topic 1. General information about bridges on military roads Lesson 1. General information about bridges on military roads
Educational goal: To form a sense of responsibility for the assimilation of the knowledge gained. Learning goal: 1. To reveal the role and importance of bridges in road support for military operations; 2. To study with students the types of artificial structures on the VAD, the classification and the main elements of military bridges.
First question. The place and purpose of discipline in the training of a reserve officer of the road troops. The content and objectives of the discipline. Second question. The role and importance of bridges in road maintenance operations. Brief historical review of military bridge building The third question. Types of artificial structures on the VAD and their significance. Tactical and technical requirements for military bridges. The main parts of the military bridge, the calculated span, the construction height of the span, the width of the carriageway, the openings of the bridge. Fourth question. Classification of bridges by purpose, by systems, by materials, by location, carriageway, by service life, by length and dimensions of the carriageway. Bridge crossing over a water barrier and the purpose of the elements that make it up.
Literature 1. Textbook VHZDV, part I, pp. 3-10; 2. Textbook "Bridges and crossings on the VAD", pp. 3 -25.
First question. The place and purpose of discipline in the training of a reserve officer of the road troops. The content and objectives of the discipline. Military bridge training aims to prepare for the Armed Forces selflessly devoted to their homeland reserve officers with high ideological and moral qualities, as well as the knowledge, skills and abilities necessary for the successful performance of their duties. The main objective of the training is to prepare a reserve officer of the road troops who has the necessary theoretical knowledge of the construction of military bridges. As a result of studying the discipline, students should: Have an idea: about the technology and organization of the construction (layout) of military bridges and crossings; on the organization of work with the material part of the standard collapsible bridges and pontoon parks; Know: basic information about bridges; structures of low-water and service demountable bridges; general information about floating bridges and ferry crossings; organization of reconnaissance of the areas of bridge construction and the area of procurement of bridge structures. To be able to: organize and conduct reconnaissance of existing bridges, organize the movement of vehicles on bridges and artificial structures on military highways.
Second question. The role and importance of bridges in road maintenance operations. A Brief Historical Review of Military Bridge Construction In the course of operations, the performance of combat missions will require a constant supply of materiel and human resources from the deep rear of the country to the theater of operations. The main role in the supply of material resources in the Great Patriotic War was played by rail transport. Automobile transport was used for transportation from the final unloading stations to the line of contact of troops, as well as in areas where there were no railways or were under restoration. Under conditions of war with the use of nuclear and high-precision weapons, the role of road transport and military highways is increasing dramatically. This circumstance makes road support of operations of particular importance in the overall system of logistical support for troops. The most important components of road support for operations are the preparation, operation, technical cover and restoration of military roads. During the period of hostilities, the enemy will actively influence communications in order to destroy, first of all, artificial structures on military highways, as the most effectively destroyed and difficult to restore objects. First of all, bridges, which played an important role in all wars, belong to artificial structures on communications.
The successful conduct of a number of major operations of the Great Patriotic War is inextricably linked with the construction, strengthening, restoration of bridge crossings and the organization of ferry crossings across water barriers. So, in the initial period of the war, during fierce defensive battles, high-water wooden bridges were built near the village. Bogorodskoye, Myaznikovo and Penkino, the bridge across the river was reconstructed for double-track automobile traffic. Oka near Serpukhov and a wooden bridge was built near Kolomna. War 1941 45 demanded that special attention be paid to military bridge building. During its course, the number of bridge units was increased 11 times, which amounted to one-fifth of the road troops in terms of personnel. During the Great Patriotic War, the road troops restored, repaired and built about 100 thousand km of roads, over 1 thousand km of bridges, including: 45.7 km of floating bridges were built, 288.9 km of low-water and 326.3 km of high-water bridges, 462.6 km of existing bridges were repaired and strengthened. The legendary Road of Life is a symbol of courage and heroism of military road builders. With the earliest onset of freeze-up in November 1941, the road workers of the Leningrad Front carried out reconnaissance of the ice road from the village of Vaganovo through Zelenets Island with branches to the Ladoga Lake station and the village of Kobona. The operation of the road began on November 22, 1941 and continued throughout the blockade of Leningrad. ice road
became a vital artery for Leningraders and the Leningrad Front. She allowed to save the lives of hundreds of thousands of people and defend the city. The difficult task of the road parts was the organization of crossings over the river. Volga near Stalingrad. To ensure the combat operations of troops across this largest water barrier, 42 ferry crossings and 6 floating bridges with trestle passages were built in the Saratov Astrakhan sector, and across the river. Akhtuba and canals in the Volga delta, 37 bridges were built and 35 crossings were built. Before the Battle of Kursk, military road builders built over 10 km of new and strengthened up to 12 km of existing bridges, including those across the Oka, Don, and Voronezh rivers. A major role in forcing the Dnieper by the troops of the 1st, 2nd and 3rd Ukrainian Fronts was played by 45 crossings built by road troops, including 2 high-water bridges near Kyiv and Dnepropetrovsk. The bridge near Kyiv across the Dnieper River, 1.8 km long with three metal navigable spans, was built in less than three months. Our bridge-building units, in cooperation with the engineering troops, built bridges from pre-prepared rams at a rate of up to 300 m per day, built low-water bridges up to 150 m, and high-water bridges up to 20 m per day. During the Belarusian operation, the road troops built and restored 3.5 thousand bridges and artificial structures with a total length of 63 km across the rivers Dnieper, Berezina, Volkhov, Sozh, Desna and others. In the course of the Berlin operation, under the blows of the latest by that time means of attack by the enemy aircraft, shells FAU 1 and FAU 2, 34 bridges across the river were built by road troops. Oder, restored 16 bridges across the river. Spree and channels.
In the liberated countries of Eastern Europe, road troops built large bridges across the rivers Vistula, Oder, Tisza, Danube and others. The courage and heroism of military road builders made a significant contribution to the defeat of the Nazis during the Great Patriotic War. A brief historical overview of the development of military bridge building The history of the development of bridge building as a whole is closely connected with the history of civilization, building art and architecture. With the emergence of large centralized states, the creation of a network of roads, which were extremely necessary for solving various tasks, including military and strategic ones, is becoming increasingly important. The construction of bridges across large rivers in antiquity presented great difficulties. The most difficult was the erection of supports. For their construction, the river was often diverted into a new, artificial channel. The Romans used impenetrable pontoon boxes that were sunk to the bottom for the construction of supports. Therefore, for crossing large rivers, bridges on floating supports in the form of rafts, boats, and ships were often arranged. Floating bridges were used in military conditions to ferry troops across large water obstacles.
Floating bridges made of rafts were widely used in Russia, starting from the Battle of Kulikovo until the Great Patriotic War. Since 1759, the Russian army began to use a pontoon park with canvas pontoons, developed by Captain Andrei Nemy. This park has existed for over 100 years. In the first half of the XIX century. in Russia, they designed and began to use collapsible wooden bridges on gantry supports, adapted to regulate the carriageway of the superstructure at a height. In the 60s of the XIX century. The Kolomna Plant developed the world's first design of a collapsible metal bridge, ahead of France and Germany in military bridge building. In the same years, a fun pontoon park with metal pontoons appeared in Russia. The bridge business received more intensive development in the Soviet Army. In 1932 39 a manual was developed for the construction of wooden bridges on pile supports at a rate of up to 5 m / h. Mechanized pontoon parks SP 9, DMP 42, DMP 45 are being created, which have passed the test of the war. On the basis of the tractor, a universal bridge-building machine was created. Widespread use during the war found the construction of bridges from local materials. In 1941, road troops used wooden barges to build bridges. Somewhat later, they began to master the construction of wooden bridges on rigid supports. Cross-bar trusses were developed from large timber and plates, which compensated for the lack of sawmill facilities. The designs of beam low-water bridges were significantly simplified, which made it possible to increase the pace of their construction. To cover large spans, Gau Zhuravsky's trusses with a ride on the bottom were used. The experience of operating bridges during the war made it possible to increase their allowable stresses for raw softwood from 130 to 180 kgf / cm 2 in the calculation, which gave savings in timber consumption.
Practice has proven the importance of advance preparation of standard bridge structures, using which the daily rate of construction of low-water bridges reached up to 80 m, and high-water bridges up to 8-12 m per day. After the war, already in the 50s, the road troops received pontoon parks of the CCI and LPP, collapsible bridges RMM 4, modern pile driving equipment and sawmill equipment. In the 60s, the road troops received sets of metal collapsible road bridges MARM, SARM, BARM, which ensure the assembly of low-water bridges in 8 hours, and the construction of high-water bridges in 24-30 hours. Nowadays, a floating road bridge, a NARM tape, and a collapsible universal bridge on rigid supports, RUM, are in service. Since the 1970s, the best PMP pontoon park in the world has been used to equip the road troops. Currently, the road troops are doing a lot of work to improve demountable bridges and technical means for their construction, as well as searching for new design and organizational solutions in the use of local watercraft and building materials.
Floating bridge from the heavy pontoon park ZIS 151 A with the bow section of the pontoon park of the Chamber of Commerce and Industry, 1954. The middle pontoon from the light pontoon park LPP on the ZIL 157 E chassis.
Third question. Types of artificial structures on the VAD and their significance. Tactical and technical requirements for military bridges. The main parts of the military bridge, the calculated span, the construction height of the span, the width of the carriageway, the openings of the bridge. The main artificial structures on highways should be considered: bridges leading the road over obstacles; tunnels that continue the road under an obstacle, in the thickness of rocks, the restoration of which is carried out by special methods using mining equipment; galleries protecting the road from snow avalanches and stone falls; balconies - cantilever structures on mountain roads; mudflows protecting the road from mudflows; retaining walls, flumes, siphons, filter embankments, etc. In addition to bridges, other artificial structures are often found on military highways: culverts, viaducts, overpasses, flyovers, tunnels, etc. Culverts are laid in the body of the embankment if the estimated flow rates of water that must be passed under the structures are small. At the same time, the subgrade of the road is not completely interrupted, which makes it possible to obtain cost savings and reduce construction time. In mountainous regions and the laying of military roads over rough terrain, it is necessary to build viaducts through valleys and gorges. The total length of the viaducts is determined by the terrain along the planned route of the military highway. Viaducts are often located on the steep slopes and turns of the VAD. To increase the capacity of military highways, it is advisable to arrange and equip their intersections, as well as intersections with railways at different levels. For this purpose, overpasses are being built. Ensuring convenient approaches to bridges, arranging junctions for numerous traffic lanes, and reducing earthworks for the device of approaches are often feasible only when replacing the subgrade of roads with overpasses.
Tactical and technical requirements for military bridges The site for the construction of a bridge or crossing is chosen, first of all, according to the smallest amount of work and the period of restoration. This should take into account the costs of constructing approaches, fencing and decontamination of the area, hydrogeological conditions of the watercourse, the possibility of masking the bridge and work on its construction, as well as the possibility of maintaining the operational qualities of the road at the crossing. Certain tactical and technical requirements are imposed on military bridges. The tactical requirements are as follows: the bridge must have convenient camouflaged approaches and areas of terrain with camouflage properties suitable for waiting areas for troops and transport, concentration of bridge building units and storage of bridge structures; the speed of the device and assembly on the barrier is the main requirement; the capacity of the bridge should ensure the passage of all military vehicles following the VAD; the carrying capacity of the bridges should ensure the passage of all military vehicles following the VAD; the service life of bridges should correspond to the type of restoration. Provide year-round operation for 3-5 years. Short-term bridges are built to ensure the passage of vehicles for a period of 20-30 days, without ensuring the passage of leads and ice drift; The transportability of bridge structures and technical means used in construction should allow their transportation by road, rail, waterways, and service bridges by air. Profitability reduction of service bridges through the use of local materials and floating facilities (barges, boats, boats). Survivability is ensured by covert and dispersed production of work, its camouflage in operation, rapid re-recovery from previously prepared
In military bridges, the following basic designations and definitions are used: LP - river width according to the estimated water level; L is the length of the bridge (the distance between the axes of the coastal supports); L 1 - the full length of the bridge along the deck of the carriageway, i.e. between the places where the bridge structures mate with the embankments of the approaches; l - span of the bridge (distance between the axes of adjacent supports); l 0 - estimated span (distance between the support axes of the span); Co - support width; H - support height (distance from the ground to the top of the nozzle); hc - construction height of the span (distance from the bottom of the span to the top of the carriageway); ho - bridge height (distance from the calculated water level to the bottom of the span); Vpch - the width of the carriageway (the distance between the inner edges of the wheel break) Lc= lc - the opening of the bridge, equal to the sum of the spans in the clear and providing the passage of flood waters; appointed by calculation; H - the height of the bridge from the level of maximum waters to the pavement of the carriageway; h is the construction height of the bridge, measured from the surface of the deck to the lowest parts of the superstructure in the span; G - the dimension of the carriageway, equal to the distance between the inner faces of the wheel breaks (for military bridges it is usually called the dimension of the bridge);
1 - coastal support; 2 - cell support; 3 - tower support; 4 - flat support; 5 - span structure; 6 - bearing part of the span; 7 wheel rebound
The axis of the bridge is an imaginary line passing in the middle of the carriageway; Support axis - an imaginary line passing in the middle of the width of the support and perpendicular to the axis of the bridge; The line of extreme piles (pillars) of supports is an imaginary line passing along the bridge along the axes of the extreme piles (pillars) of intermediate supports. Bridges in most cases are built through water barriers, which are characterized by a certain regime. The river regime is the behavior of the river during the year or during the specified lifetime of the bridges. the river regime should be understood as a change in water horizons, the timing and nature of freezing, ice drift, a change in the speed of the flow of water, a change in the direction of the jets of flow, etc. Rivers change their water horizon during the year: in summer they become smaller, during heavy rains and when When snow melts, water rises, which is called a flood. Floods in summer are typical for mountain rivers, and in autumn and spring - for flat ones. In spring, as a result of snowmelt in most lowland rivers, a large rise in water occurs and they overflow their banks. This condition on the rivers is called high water.
The characteristics of floods and floods on each river vary from year to year. Therefore, bridges are built for a certain period of operation, they are calculated for the maximum rise that is possible during this period. In the characteristics of the watercourse, the following designations are accepted: WWW - high water level - the highest water level observed in a given river for several years during a flood or high water. LMW - low water level - the most stable summer and winter level characteristic of this river; DCS - design navigable level; RUWV - design high water level (the highest water level that can be expected for the entire period of operation of the bridge); SWL – high ice drift level – water level at the highest ice drift; UNL - low ice drift level - water level at the lowest ice drift.
The living section of the river is the part of the cross section of the river that is washed by water. The main channel is a living section at the low water horizon. The left and right floodplains are parts of the cross section of the river, bounded on the right and left by low water cutoffs.
Fourth question. Classification of bridges by purpose, by systems, by materials, by location, carriageway, by service life, by length and dimensions of the carriageway. Bridge crossing over a water barrier and the purpose of the elements that make it up. Classification of bridges Military bridges are classified according to various criteria. According to the service life, bridges are short-term and temporary. Short term. bridges are designed for a short service life (from several weeks to one year) and have the simplest design. These bridges do not provide passage of ice drift or high floods. The speed of movement on short-term bridges may be less than the speed on the road. We will allow additional restrictions on the speed of vehicles on short-term bridges and their mass, depending on the operating conditions. Short-term bridges can be low-water, underwater and floating bridges, as well as bridges in the form of superstructures of superstructures and supports on the preserved structures of destroyed capital structures. For short-term restoration, ferry, ice and pile ice crossings are also organized.
Temporary bridges are designed for normal year-round operation and are calculated for a service life of 3-5 years with a constant bridge carrying capacity and without a significant reduction in the speed of traffic on the bridge compared to its movement on other sections of the road. Temporary bridges can be: high-water bridges on rigid supports built from local materials to bypass destroyed capital bridges; high-water bridges on rigid supports assembled from service property. In wartime conditions, most often it is necessary to build short-term bridges and less often - temporary ones. According to the conditions for ensuring the passage of high waters and ice drift, bridges are divided into high-water, low-water, underwater and smooth.
High-water bridges are built taking into account year-round operation, they have significant spans, large support heights and a relatively complex structure. High-water wooden bridge across the Oka River
Low-water bridges have a minimum elevation of spans above the water and do not provide passage of high flood waters and ice drift. These bridges have small spans, the simplest design and insignificant (within the season) service life.
At underwater bridges, the carriageway of the span is located 30-50 cm below the water level. They are more resistant to the effects of the damaging factors of an atomic explosion (shock wave, light radiation), and also provide more reliable masking of the bridge as a whole. The crossing of tanks on the underwater bridge "Span
Floating bridges are arranged on floating supports or in the form of a floating tape. For the passage of ships, the device of output links is provided. At the time of the flood, ice drift, floating bridges are dismantled.
According to the width of the carriageway, bridges are classified into single-track and double-track. According to the type of building materials, bridges are wooden, metal, reinforced concrete, combined. Bridges are divided into small, medium and large sizes. Bridges with a length of up to 25 m are called small, medium - from 25 to 100 m, large - more than 100 m. According to the system (scheme of the static operation of the span), bridges are divided into beam, strut, truss, arch, suspension, combined. The choice of the bridge system and the characteristic features of its design depend on the required span of the bridge, the height of the supports, the magnitude of the planned loads, as well as the available building materials. By the nature of the structures used, bridges are distinguished from service structures of industrial production and from local materials of military production. Service bridges include pontoon parks and collapsible bridges on rigid supports. Their advantages are multiple use, short assembly time, mobility during transportation. For military-made bridge elements, mainly local materials are used. They can be prepared in advance or during the construction of the bridge. As a rule, blocks of purlins, blocks of roadway shields, track blocks, Gau Zhuravsky trusses, plank nail trusses, etc. are prefabricated. This ensures timely solution of the tasks of high-speed construction of bridges in a combat situation.
According to the carrying capacity, bridges of increased, normal, reduced and low carrying capacity are distinguished. Bridges of increased (80 t) carrying capacity ensure the movement of all existing loads. Bridges of normal (60 tons) carrying capacity are recommended to be built on military highways. Bridges of reduced (25 and 40 tons) carrying capacity are built on roads where the actual freight traffic corresponds to this carrying capacity. Lightweight bridges are built on roads reserved exclusively for motor vehicles.
Elements of a bridge crossing A complex of engineering structures that ensures normal processing and continuous operation of the bridge during the planned service life is called a bridge crossing. The bridge crossing consists of a bridge, approaches to the bridge, ice cutters, regulation structures and bottom protection devices. Depending on local conditions and conditions of the combat situation, some elements of the bridge crossing may be absent, with the exception of the approaches to the bridge and the bridge itself. The bridge is the main structure of the bridge crossing. It consists of superstructures and supports. The superstructure is designed to bridge the gap (span) between the supports and consists of a carriageway and a bearing part.
The carriageway creates a comfortable driving surface, absorbs forces from moving loads and transfers these forces to the bearing part. The bearing part is designed to absorb loads from the roadway and transfer forces from these loads and its own weight to the supports. The greater the distance between adjacent supports, the more complex the design of the bearing part, and vice versa. At small distances (spans), the simplest bearing part is used in the form of a series of beams, called girders of supports laid on nozzles. For large spans, various kinds of trusses or metal beams with a solid wall of large sections and dimensions in height are used as a bearing part. The supports are designed to maintain the superstructures at the required height and to transfer all forces from the superstructures to the ground. Wooden bridges are used in military bridge building. Depending on the characteristics of the barrier, they can be pile, frame, pile-frame, cellular or woven. Approaches to the bridge are sections of the road that are directly adjacent to the bridge, conjugating its carriageway with the road. Depending on the conditions of the area, they can be arranged in the form of an embankment or a recess.
The height of the approach embankment is recommended to be no more than 1.5-2 m, with a higher height it is more profitable to replace the approach embankment with a bridge overpass on rigid supports. To protect against flooding of approaches with water, the height of the embankment should be higher than the expected level of high waters. For approaching low-water bridges - at least 1 m. Directly at the bridge, approaches in the form of an embankment end with a cone fill or fence walls. The steepness of the embankment slopes, depending on its height, the water velocity of the water flow along the embankment, the type of soil of the embankment itself and the bottom of the slope, is taken 1: 1–1: 2. And with clay and loamy soils, strong waves and fast flow speed - 1: 2, 5 1: 3. The steepness of the frontal slopes of the cones is assigned from 1: 1 to 1: 1, 75. If the height of the embankment of approaches is more than 1.5 m, a restriction for the safety of traffic must be arranged and the embankment in the form of vertical gouges, installed every 1, 5 2 m on both sides along the edges of the subgrade. At a distance of 150-200 m from the bridge, the approaches should, if possible, be widened with a length of at least 100 m to accommodate damaged vehicles, make it easier to bypass them, and also to stop vehicles in the event of an enemy air attack. Near the approaches, shelters are arranged for personnel and equipment. In areas of approaches where there are natural shelters, exits are made and signs are posted indicating the presence of shelters. In bridge crossings, when long embankments are arranged on the floodplains, during the passage of high flood waters, a strong restriction of the living section of the water flow is formed. Near the cones, along the embankments, at the supports and ice cutters of the bridge, various eddies and whirlpools are formed, which lead to erosion of their foundations. To eliminate erosion and ensure the smooth flow of flood waters, regulatory structures (jet guide dams, traverses, etc.) are arranged under the bridge.
Jet dikes are usually built on rivers with large floodplains on one or both banks. The outline of dams in the plan is assigned on the basis of data from the study of river regimes. It can be curvilinear or consist of curved parts and a straight insert. Often the outline of the dams is assigned according to a parabola. The head of the dam is arranged up to 4-5 m wide, the slopes of the river part are not steeper than 1: 2. To protect the embankment from erosion by flood waters, traverses are arranged on the upper side, and sometimes on its lower side, which deviate to the side the currents that arise along the embankment. Regulatory structures during the construction of bridges on the VAD, as a rule, are not erected, but they have to be brought into working condition and operated during the temporary restoration of bridges across large water barriers. On rivers that are covered with ice in winter, the supports of wooden bridges need to be protected from damage that can occur as a result of ice during ice drift. The impact of ice poses the greatest danger to bridges, especially during intense ice drift due to the large force of ice impacts, as well as due to the formation of congestion. To protect the supports, ice cutters are installed, the purpose of which is to crush large ice floes, protect the bridge supports from ice floes and direct floating ice floes into the spans of the bridge. Since the strongest ice drift is observed in places of the greatest depths and speeds of the river, the main attention should be paid to the protection of the river bridge supports. Supports in floodplain areas in most cases can be protected by lighter ice cutters, and coastal ones, as a rule, do not require ice protection. According to the location, ice cutters are divided into pre-bridge and outpost.
Bridge bridges can have a structure combined with supports, or in the form of separate ones at a certain distance from the supports. The distance from the ice cutters to the supports is assigned depending on the speed of the current. If, during a fast current, the ice cutters are placed too close to the support, then the ice floes, breaking against the ice cutters, may have time to damage the supports. Therefore, with a fast current, the ice cutters move away from the supports at a greater distance than with a weak one. The width of the ice cutter is assigned a little more than the width of the support, or at least equal to it. On rivers with especially strong ice drift, they are not limited to one row of ice cutters, but put in front of the first row a second row of ice cutters, called outposts. They take on the most powerful blows of the ice fields and break them into smaller pieces. Such ice cutters are placed only in the main channel, where there are the highest current velocities. In the construction of military high-water bridges, the following types of ice cutters are used: cluster normal, cluster reinforced, flat (single-row, double-row), cylindrical and tent. Bottom-strengthening and bank-protecting devices help to increase the service life of bridge crossings.
(sixties-eighties)
Pontoon-bridge park PMP
The term "pontoon-bridge park" means a set of equipment for building bridges over water obstacles, the carriageway of which rests on floating supports (pontoons). From the same property, as a rule, ferries can also be assembled to transport people and equipment through water barriers. In addition, the fleet may include vehicles for transporting property (but not necessarily).
The pontoon-bridge fleet of the PMP brand, which has been in service with the Soviet Army since 1962, is designed to build pontoon bridges up to 227 meters long for loads of 60 tons, pontoon bridges up to 382 meters long for loads of 20 tons, as well as to assemble ferries of various carrying capacities. Permissible flow velocity up to 2.5m. in sec. Unlike all its predecessors, the PMP bridge does not have separate pontoons and a separate carriageway. He has the upper part of the pontoons is the roadway
The PMP fleet includes 32 river units, 4 coastal units, 2 lining, 12 tugboats. 38 specially converted KRAZ-255V vehicles are used to transport links and linings (the first series of the park were transported by KRAZ-214 vehicles). Boats of the BMK-90, BMK-130 or BMK-150 type are towed on trailers or their own wheeled chassis by 12 Zil-130 (Zil-157) vehicles. When the fleet is equipped with boats of the BMK-T type, these boats are transported by 12 KRAZ-255V vehicles on car platforms.
One KRAZ vehicle transports one link, consisting of two middle and two outer pontoons connected by articulated joints. In the transport position, the link is transported folded on the vehicle platform. The figure shows a car with a river link. 
In the figure showing the car with the link at the rear, two middle pontoons of a rectangular shape and two extreme rounded ones are clearly visible. The coastal link differs from the river link in its shape, which allows the bridge to mate with the coast and the presence of folding exit ramps.
The calculation of the link should consist of a driver and two pontoons. 
According to the state, the calculation of the link consists of a pontoon driver and a pontoon. When building a bridge or assembling a ferry, the car drives into the water in reverse so that the depth at the point of discharge is about 1 meter; then abruptly slows down; the pontoon next to the machine releases the stopper; and the link lying freely on the rollers of the platform rolls into the water.
After hitting the water under the influence of buoyancy forces and torsion hinges, the link opens. The figure shows the link at the moment of opening (rear view). The link at this moment is held near the shore by a mooring line, the second end of which is attached to the car. The pontooner driver and pontooner rise to the deck, lock the bottom and deck locks, thereby turning the link into a rigid structure.
In the figure, the link is opened (rear view). After locking the locks, the pontooners of neighboring links with the help of hooks bring their links together and connect them with locks. The ribbon of the bridge is thus assembled along the coast. The collected tape of the bridge is held near the shore by mooring lines attached to the cars. As the tape is being assembled, the machines drop the mooring lines and go to the collection area. The width of the carriageway is 6.5 meters.
After the bridge tape is assembled, it is turned across the river with the help of tug boats, the coastal links are fixed near the shore with mooring lines, and the tape itself is kept in the course by boats until the moment of delivery and dropping of the anchors available on each link. After tensioning the anchor cables and aligning the tape, the boats are disconnected and leave. 
The figure shows a part of the bridge tape (top view). The dark green color shows the carriageway 6.5m wide. This width of the carriageway allows tanks to move along the bridge at speeds up to 30 km. per hour, and wheeled vehicles without speed limits. Moreover, wheeled vehicles can move along the bridge in two columns, or simultaneous movement along the bridge in both directions is possible. With this assembly scheme from one set 
kta it is possible to assemble a bridge for loads of 60t. length up to 227m.
For loads of 20t. bridge layout is different. The link opens on one side and turns 180 degrees. The bridge tape in this case looks like this: "link in the usual form - link deployed - link in the usual form - ...". The width of the carriageway then is only 3.3 m, but from one set you can assemble 
st 382 meters long.
For crossing equipment and personnel through water barriers, the width of which exceeds the capabilities of the bridge, 16 ferries with a carrying capacity of 40 tons, or 12 - 60 tons, or 8 - 80 tons, or 4 120 tons, or 4-170 tons can be assembled from one set of PMP . Ferries are towed by tugboats. Each ferry is a separate section of the bridge.
The lining is a metal strip laid on the platform of the KRAZ vehicle from separate links hinged to each other. The pavement is designed to enable transported vehicles to enter the bridge in the conditions of a swampy shore. The use of pavement is permitted only in wartime, because. tanks for one crossing bring the pavement into complete disrepair.
The PMP park of the full set is in service with the army or front-line separate pontoon-bridge battalion (OPOMB). The battalion consists of two pontoon companies (16 river, 2 coastal units, 6 boats and 1 lining in the company), a separate engineering and technical platoon armed with a set of KMS bridge-building equipment (or a USM bridge construction unit), a set of heavy mechanized bridge TMM. This platoon is designed to ensure the closure of the banks with the help of small bridges on supports with a lack of pontoons. In addition, the battalion has a repair and maintenance platoon. In total, there are about 250 people in the battalion.
In addition, the engineering battalion of a tank (motorized rifle) division has a pontoon company (0.5 PMP sets). From this half of the kit, you can assemble a half-length bridge or the corresponding number of transport ferries.
Bridge building time for loads 60t. in the daytime 30 min, for loads of 20t. afternoon 50 min. At night, the rate doubles.
According to the combat regulations, the battalion advances to the river in the first echelon of the division. The building of the bridge is started after crossing the water barrier with the first wave of landing on floating equipment (infantry fighting vehicles, armored personnel carriers, PTS) as soon as the possibility of shelling the water surface of the barrier from small arms and mortars is excluded.
From the author. By 1978, the Americans, without further ado, simply copied the PMP fleet with the only difference that the pontoons were made not of steel, but of duralumin, and placed them on their cars. And so even the number of bolts on the access hatches inside the pontoon is the same.
In the sixties, Czechoslovakia produced a PMP fleet under license, placing it on its four-axle Tatra vehicles.
In the late eighties, a late version of the PMP park was produced under the name PPS-84. This fleet was located on KRAZ-260 vehicles and had BMK-460 boats.
In the summer of 1979, 1257 separate pontoon-bridge battalion of the Central Group of Forces under the command of Lieutenant Colonel Skryagin A.V. during exercises near the village of Gorni Pochapli on the Laba (Elbe) river, he gave a bridge in the daytime in 13 minutes 42 seconds, at night in full blackout conditions in 29 minutes 54 seconds.
Theoretically, any number of links can be connected in one tape. The author observed the assembly of the bridge from two sets of PMP (430 meters). However, such a tape is difficult to keep on the course. The anchors do not hold, and the motors of the boats holding the bridge quickly overheat. It is difficult for the commander to coordinate the work of a large number of boats. So the bridge is 227m. optimal. With a greater width of the water barrier, it is more expedient to cross by ferry.
For comparison: The predecessor of the PMP park, the CCI park, with approximately the same length of the bridge, was transported by 98 vehicles, assembled in 3-4 hours, and 995 people were required for its operation (pontoon-bridge regiment).
Sources
1. Instructions for the material part and operation of the PMP pontoon-bridge fleet. Military publishing house of the USSR Ministry of Defense. Moscow 1966
2. Military engineering training. Tutorial. Military publishing house of the Ministry of Defense of the USSR. Moscow. 1982
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Guidelines for military low-water bridges contain instructions for the construction of low-water and underwater bridges and overpasses on rigid supports built from local materials
Chapter 2. Engineering reconnaissance of the bridge construction area
Chapter 3
1. Block spans
Span structures from gauge blocks
Span structures from blocks of runs and boards of the roadway
a) Blocks of simple runs
b) Blocks of complex runs
c) Blocks of compound runs
2. Span structures from individual elements with simple and complex runs
roadway
Simple runs
Complex runs
Chapter 4
1. Block spans
Blocks of four runs
Blocks of two runs
roadway
2. Superstructures from individual elements
Support structure with simple purlins and bundles
Supporting structure with stacked girders
roadway
Chapter 5
1. Pile supports
2. Frame wooden supports
3. Cellular supports
4. Ensuring longitudinal stability of the bridge
Chapter 6
Chapter 7
1. General Provisions
2. Manufacturing of structures of low-water wooden bridges
logging work
sawmill work
Works on the manufacture of wooden bridge structures
Manufacture of track blocks
Assembly of run blocks
Manufacture of span structures from purlin blocks and roadway shields
Features of assembling blocks of complex runs
Production of composite purlins on steel cylindrical pins and assembly of blocks from two purlins
Piling manufacturing
Manufacture of nozzles and bed supports
Manufacture of elements and assembly of frame supports
Features of manufacturing elements of bridge structures in the construction of bridges from individual elements
3. Fabrication of metal bridge structures
General provisions
Manufacturing of metal elements
Production of roadway elements
Production of run blocks
Manufacture of span structures from individual elements
4. Transportation of bridge structures
Chapter 8
1. General Provisions
2. Breakdown of the axle of the bridge and axes of the supports
3. Means of mechanization of work in the construction of bridges
4. Depth of pile driving in supports
5. Organization of work in the construction of low-water bridges
General provisions
Construction of bridges on pile supports using a set of bridge building tools KMS
Construction of bridges on pile supports using DM-150 diesel hammers with OSK single-boom pile drivers and DB-45 diesel hammers with PUS-1 devices for installing piles
Construction of bridges on frame supports using ferries with jacks from the KMS kit
The device of coastal supports and interfaces of the bridge with the banks
Building bridges from individual elements
Features of the construction of double-track bridges on pile supports
Features of the construction of bridges on pile supports with increased spans
Chapter 9
1. General Provisions
2. Design features of intermediate supports
3. Coastal supports and interface of the underwater bridge with the shores
4. Features of the design of span structures of underwater bridges
5. Features of the construction of underwater bridges on piles
6. Features of the construction of underwater bridges on frame supports
7. Features of the construction of underwater bridges with metal girders
Chapter 10
1. Winter bridges
2. Combined bridges
3. Bridges over water barriers with high flow rates and rocky bottom
General provisions
intermediate supports
Features of the construction of bridges on rivers with high flow rates
4. Bridges over canals and narrow barriers
Chapter 11
Chapter 12. Operation and maintenance of bridges
1. Acceptance of bridges
2. Rules for driving on bridges
3. Operation of bridges
4. Elimination of damaged bridge elements
5. Preparation of bridges for the passage of ice drift and flood
6. Passage of ice drift and flood
7. Bridge security
Chapter 13
1. General Provisions
2. Bridge survey
3. Determination of the carrying capacity of steel and wooden bridges
Chapter 14
1. Basic provisions
2. Calculation of flooring and cross members
3. Calculation of runs
4. Calculation of supports
Determination of pressures
Selection of sections of piles and racks
Selection of sections of the nozzle and bed
Calculation of linings under the bed of the frame support or under the bank bed
5. An example of the calculation of a low-water bridge on pile supports
Appendix 1 Timber data
Appendix 2. Data on metal rolled beams and rails
Appendix 3. Data on composite runs from rolling I-beams and rails
Annex 4. Data on forgings and nails
Annex 5. Data on ropes and cables
Appendix 6. Determination of the strength of coniferous wood by firearms
Appendix 7. Engineering reconnaissance card of the bridge construction area
Annex 8. Data on engineering reconnaissance means
Appendix 9. Exploration of the forest
Appendix 10. Field design of a low-water bridge on piles
Annex 11. Specification of elements and structures of the bridge
Appendix 12
Appendix 13. Tactical and technical characteristics of bridge-building facilities
Appendix 14. Data on machines for welding and cutting metal
Annex 15. Data on truck cranes
Annex 16 Vehicle Data
Annex 17. Consumption of timber and metal per 1 linear meter of wooden span
Annex 18. Indicative norms for the construction of low-water bridges
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| 05.11.1964 | Approved | ||
|---|---|---|---|
| Published | 1965 |
Guidelines for the Use of Expanded-Clay Lightweight Concrete In Road and Highway Bridges
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MINISTRY OF DEFENSE OF THE USSR
MANAGEMENT- ON MILITARY, LOW-WATER BRIDGES
MILITARY PUBLISHING HOUSE OF THE MINISTRY OF OBSORONA OF THE USSR MOSCOW-1965
MINISTRY OF DEFENSE OF THE USSR
APPROVED
MANAGEMENT MILITARY LOW-WATER BRIDGES
MILITARY PUBLISHING HOUSE OF THE MINISTRY OF DEFENSE OF THE USSR MOSCOW - 1965
ki, should not exceed 1:500 in the vertical plane and I:250 in the horizontal plane of the beam;
The local curvature of the beam, determined by the ratio of the arrow of the local bend (dent) to its length, should not exceed 1: 200 for the chords and 1: 100 for the wall; with greater curvature (general and local), it is necessary to straighten the beams before starting the manufacture of bridge structures;
The defeat of beams (rails) by rust should not exceed 1 mm, with a greater defeat by rust, but not more than 2 mm, the bearing capacity of the run is recalculated;
Cracks and local damage (flaws) in the beams are not allowed;
The wear of railway rail heads must not exceed 15 m in height;
Beams (rails) exposed to flame cannot be used if they have deformations, burns and cracks; signs of metal burnout are melted places and scale films. Data on rolled I-beams and channel beams, as well as broad gauge railway rails, are given in Appendix 2.
18. Metal forgings (pins, brackets, clamps) necessary for connecting elements of bridge structures are made of round, square and strip steel.
The necessary data on metal forgings, as well as on round steel and nails, are given in Appendix 4.
Data on hemp ropes and steel cables are given in Appendix 5.
ENGINEERING REVIEW OF THE BRIDGE CONSTRUCTION AREA
19. The purpose of engineering reconnaissance of the bridge construction area is to obtain data that provide the ability to:
Choosing a place to build a bridge (if it is not set) n approaches to it;
Determination of places for procurement of materials and elements of the bridge;
Choice of ways of transportation of prepared materials and elements of the bridge;
Drawing up a bridge diagram;
Determining the amount of necessary materials and elements;
Making decisions on the organization of work.
20. Engineering intelligence establishes:
The main features of the barrier and the bridge construction site (the nature of the bottom soil, banks and approaches, the profiles of the banks and approaches to the bridge, the presence and condition of roads suitable for the bridge, etc.);
Profiles of a live (transverse) section of a water or other obstacle in places possible for the construction of a bridge;
The regime of the water barrier in the area of the bridge construction (velocity and features of the current, horizons of low water, possible fluctuations in the water horizon during the operation of the bridge);
The presence of dams, locks and other hydraulic structures and the nature of their possible impact on
the operation of the bridge under construction in cases of water leakage or destruction of these structures;
Availability of the necessary building materials in the bridge construction area (standing timber, warehouses for finished timber materials, metal beams, metal for forgings, materials for various buildings, etc.);
Availability of manufacturing facilities that can be used to manufacture bridge elements and forgings;
Availability and condition of ways to transport materials and elements of the bridge from the place of harvesting to the barrier;
Necessary camouflage measures in the places of procurement of materials and elements, in the place of construction of the bridge, as well as in the place of construction of false bridges;
The nature and scope of work on the arrangement of shelters for crews, mechanization equipment and materials from possible enemy impacts (extraction of trenches, crevices, etc.);
The presence and nature of barriers on the water barrier and on the approaches to it.
21. For engineering reconnaissance, a patrol is appointed, depending on the width of the water barrier, consisting of:
With a barrier width of no more than 50 m - up to one squad led by an officer, and a sergeant with two or three soldiers is assigned to reconnaissance of materials, and the officer in charge of reconnaissance, with the rest of the soldiers, performs reconnaissance work on a water barrier;
With a barrier width of more than 50 m - up to a platoon with two officers; the officer in charge of reconnaissance, with the soldiers, conducts reconnaissance work on a water barrier; another officer with soldiers is allocated for reconnaissance of materials.
22. Engineering intelligence data are entered into the engineering intelligence card (Appendix 7) and onto the map at a scale of 1:100,000-1:500,000. The profile of the active section of the obstacle along the axis of the bridge is attached to the engineering intelligence card (Appendix 7).
On the map they put: the axis of the bridge, approaches to it, places for harvesting timber and bridge structures, ways of transporting materials and elements from the place of procurement
to the construction site, the location of barriers and hydraulic structures, indicating their nature.
On the drawn profile of the living section of the barrier, indicate: the speed of the current, possible changes in the water horizon during the operation of the bridge, the nature of the soil of the bottom and banks, the slopes of the banks.
23. A patrol allocated to engineering reconnaissance must have a map, a compass, a sapper rangefinder, binoculars, a field hydrometric turntable or a hydrospeedometer, an engineering reconnaissance echo sounder (IREL) or a river reconnaissance apparatus (AR-2), bottom probes, a weight striker, measuring tapes or tracing cords, thin rope or wire, slats or poles with divisions, level, plumb line, entrenching tool, swimming suits, boats. In addition, the patrol should be armed with means of reconnaissance and overcoming obstacles, as well as one or two armored reconnaissance vehicles (BRDM) and communications equipment.
24. When conducting engineering reconnaissance, the following methods are used, depending on the situation and the nature of the water barrier, to obtain the necessary data:
The profile of the clear section of the water barrier is taken by an engineering reconnaissance echo sounder (IREL), a river reconnaissance apparatus (AR-2) and direct soundings;
The width of the water barrier is determined by a sapper rangefinder, binoculars, theodolite, a geometric method and direct measurement;
The speed of the water flow is measured with a hydrometric turntable, hydrospeedometer or float;
The nature of the soil of the bottom, banks and approaches is established by a bottom probe, and the density of the soil of the coast is determined by a weight striker;
Profiles of banks and approaches are removed by leveling or spirit leveling.
25. When choosing a bridge construction site, the following tactical requirements are taken into account:
If possible, locate bridges, especially underwater ones, in meanders or on sections of the river separated by rifts, characterized by increased protective
properties in relation to the action of surface waves from a nuclear explosion;
Bridges should not be built in order to reduce the impact of enemy aircraft on them near settlements, especially large ones and those located on railway lines, warehouses, bases, etc.;
The distance between adjacent bridges, in order to exclude the possibility of simultaneous destruction of several bridges by one nuclear explosion, must be at least twice the safe distance corresponding to the highest probable yield of a nuclear weapon;
The approaches chosen for the bridge should be distinguished by secrecy, but ensure the movement of cars without delays and congestion;
The bridge construction area should allow shelters for crews, mechanisms, prepared elements and materials.
26. When choosing a bridge construction site, the following technical requirements should also be taken into account:
To locate the bridge, if possible, on the section of the river with the smallest width and depth of water, with a smooth change in depths and acceptable ground conditions;
It is desirable to place the bridge target on a straight section of the river with a regular straight-jet flow;
It is necessary to assign the axis of the bridge perpendicular to the direction of the flow, and in case of insufficiently correct movement of the flow - perpendicular to the direction of the flow in the main, deepest part of the channel;
If it is necessary to build a bridge near the mouth of the tributary, remove the bridge at least 100-150 m from the mouth of the tributary downstream or at least 30 m upstream;
It is necessary to avoid such places for the construction of bridges that require significant work on the arrangement of approaches and do not provide convenient placement of prepared elements and materials for the construction of the bridge.
27. Removing the profile of the living section of the river with an IREL engineering reconnaissance echo sounder is carried out in accordance with the instructions of the IREL Description and the Instruction
station for its operation, and the reconnaissance apparatus of the AR-2 river - in accordance with the instructions in Appendix 8.
28. To obtain a profile of the living section of the river by direct measurement, measure the width and at the same time determine the depth of the water in accordance with the instructions of Art. 29 and 30.
29. Direct measurement of the width of the river is carried out by pulling from one bank to another a cable, a tracing cord, a rope, a wire marked with marks every 1-2 m. At night, to ensure visibility, patches of white matter are tied to them. On large water barriers, steel cables are used, pulled by winches, gates or a floating machine. In order to eliminate significant sagging, the cable is supported by buoys or boats.
30. A direct measurement of the depths is carried out using a pole, hook, rail or lot, and simultaneously with the measurement of the width of the river. The measurement is carried out from a floating car or a boat moving along the cable along the intended axis of the bridge. The distances between the depth measurement points are assigned depending on the width of the water barrier (5 m on rivers up to 100 m wide and 7-10 m on wider rivers) and taking into account the presence of significant local changes in depths that require additional measurements.
During the construction of bridges on frame supports, the water depth is measured at the installation sites of the supports, while at three points along the axis of the bridge and at the ends of the beds.
31. Measurement of the width of the river with a sapper rangefinder is carried out in accordance with the instructions for working with a sapper rangefinder and Appendix 8.
32. When measuring the width of the river with binoculars, they are sighted from parking lot A (Fig. 2) on two preferably vertical objects located at the edge of the opposite bank, and on the scale of the rangefinder of the binoculars, the number of divisions n is placed between these objects. Then
15
With the publication of this Guide, the Manual for Engineers "Low-water bridges", ed. 1955
GENERAL PROVISIONS
1. Guidelines for military low-water bridges contain instructions for the construction of low-water and underwater bridges and overpasses on rigid supports built from local materials.
2. Bridges on rigid supports made of local materials are built on the routes of movement of troops through various types of obstacles:
To replace bridges from standard crossing facilities in order to quickly release them and advance to subsequent obstacles;
In combination with floating bridges across wide water barriers;
In cases where the use of personnel funds is impossible or impractical;
When restoring destroyed permanent bridges.
3. Military bridges on rigid supports include low-water and underwater bridges, overpasses, as well as high-water bridges.
Low-water bridges are built without taking into account the possibility of strong ice drift, high waters and ships (on navigable rivers) passing under them. These bridges have small spans, the simplest design and a short service life.
Underwater bridges differ from low-water ones in that their roadway is under water during operation, which contributes to greater secrecy and increased survivability when exposed to a nuclear explosion.
Overpasses are erected at the intersection of roads with heavy traffic in order to ensure the movement of loads in two levels.
High-water bridges are built taking into account their operation for a long time, the possibility of passing high waters under them, ice drift and ships (on navigable rivers). These bridges have significant spans, high supports and a relatively complex structure.
4. The following basic requirements are imposed on low-water and underwater bridges, as well as on overpasses built from local materials:
High rates of work, ensuring the construction of bridges in a given, as a rule, short time;
Perhaps less labor intensity of work performed on the barrier, contributing to the reduction of the required calculations and time for the construction of bridges;
Reliability of bridge structures, providing repeated skipping of design loads;
The survivability of bridges, which ensures, if possible, equal strength of individual parts and fasteners when exposed to a nuclear explosion, as well as the ability to skip loads if individual elements are damaged and quickly restore the bridge in case of partial destruction;
The speed of development by calculations of methods for manufacturing bridge structures and methods for building bridges in various conditions.
Fulfillment of these requirements is ensured by:
Organization of work on a wide front with the maximum use of mechanization for all types of work;
The wide use of pre-fabricated elements and blocks adapted for their transportation to the place of construction and providing the possibility of producing on the barrier mainly only assembly work;
The use of simple bridge structures that allow the widespread use of mechanization in the manufacture and assembly of bridges on an obstacle.
5. A military low-water bridge on rigid supports (Fig. 1) consists of a span and supports. The span structure is formed from the carriageway and the bearing parts. The carriageway, along which the movement of loads occurs, transfers their pressure to the bearing part. The bearing part perceives the pressure from the load passed through the bridge and the own weight of the superstructure and transfers them to the supports.
Supports, supporting the superstructure, transfer pressure from the transmitted loads and the own weight of the bridge to the ground. Supports located on the banks are called coastal, and the rest - intermediate.
6. The span structure of low-water and underwater bridges and overpasses adopts the simplest split beam system. Its structure is formed from:
Separate runs of various types (simple, complex, composite) supporting the roadway from the boards;
Blocks of various types (track blocks and blocks of runs with roadway shields).
7. In military bridges, the following basic definitions and designations are used (Fig. 1):
L p is the width of the river along the calculated horizon;
Bridge length L - distance between the axes of coastal supports;
Bridge span / 0 - distance between axes of adjacent supports;
Estimated span I of the bending elements - the distance between the axes of their support;
Carrier^\l
part "1" g 1
U1iniya extreme piles
Rice. I. Scheme of a low-water bridge
axle axle
Support axis - a line passing in the middle of the width of the support and perpendicular to the axis of the bridge;
Line of extreme piles (pillars) of supports - a line passing along the bridge along the axes of the extreme piles (pillars) of intermediate supports.
8. In the designs given in the Guide, the impact on the bridge of the following loads is taken into account:
Self weight of bridge elements;
Movable caterpillar or wheel load;
Horizontal wind pressure;
Shear force from the reversal of a moving load on the bridge;
Braking force from moving load;
Shock wave of a nuclear explosion.
9. The carrying capacity of low-water bridges is characterized by the largest weight of a single track load passed over the bridge.
For these bridges on rigid supports made of local materials, two load capacities are installed - 60 and 25 tons.
On bridges with a carrying capacity of 60 tons, you can pass:
Caterpillar loads weighing up to 60 g;
Wheel loads with wheel pressure up to 8.0 g;
Road trains in the form of a tractor with a heavy-duty trailer with a total weight of up to 90 tons.
On bridges with a carrying capacity of 25 tons, you can pass:
Caterpillar loads weighing up to 25 g;
Wheeled with pressure on the wheel up to 4.0 g.
Data on the calculated moving load are given
10. The own weight of bridge structures is determined according to the designed dimensions or according to the tables given in Appendix 17.
When determining the own weight of bridge structures, the following calculated volumetric weights of wood and metal are taken:
Pine, spruce, poplar - 600 kg / m 3
Larch, birch, beech - 700 kg / m 3
Oak - 800 kg / m 3;
Siberian fir - 500 kg / m 3;
Steel - 7850 kg / m 3.
11. Low-water and underwater bridges, as well as overpasses are built, as a rule, single-track; double-track bridges are built only on low-water bridges on roads with heavy traffic in two lanes. Double-track bridges are built with a carrying capacity of 60 tons.
The width of the carriageway of military bridges on rigid supports is taken:
For single-track bridges with a carrying capacity of 60 g - 4.2 m
For single-track bridges with a carrying capacity of 25 g - 3.8 m;
For double-track bridges - 6.0 m.
On single-track bridges, it is allowed to pass moving loads with an offset close to one of the wheel breaks.
On double-track bridges, all wheeled and caterpillar loads weighing 25 g or less are passed in two columns, and loads with a total weight of more than 25 tons - in one column with an offset relative to the bridge axis of not more than 0.75 m.
12. When constructing low-water bridges on rivers with flotillas operating on them, if necessary, provide for the installation of output links for the passage of ships.
13. For the construction of bridges from local materials
Fishing uses timber materials, rolled steel beams, broad gauge railway rails, forgings (bolts, pins, clamps, staples), nails, as well as various auxiliary materials.
14. Forest materials are harvested in the forest, used found in warehouses, and also obtained from the dismantling of various buildings.
The most widely used for the construction of bridges are pine and spruce.
The necessary data on timber are given in Appendix 1.
15. The following requirements are imposed on timber materials used for the construction of military bridges:
Rot, wormhole (except for the superficial one, from bark beetle), curling, loose and tobacco knots are not allowed;
Healthy knots are allowed with a diameter of not more than "/4 of the diameter of the log or the width of the beam and board;
Cracks are allowed with a depth of not more than * / h of the diameter of the log or the thickness of the beam and board for each not more than "/ h of the length of the element;
The cross-cut is allowed no more than 15% in logs and 8% in beams and boards.
The most straight-layered and with the least number of knots and cracks, timber material is selected for extreme runs, transverse decking, nozzles and supports. For piles and racks of frame supports, straight-layer logs are used, but logs with knots and cracks are also allowed.
16. In case of doubt about the quality of timber materials intended for the construction of bridges, their actual bending strength is determined using a Makarov pistol using the gunshot method described in Appendix 6.
The actual flexural strength determined by this method of timber suitable for use in the construction of bridges should not be less than 250 kg / cm 2.
17. Rolled beams and rails used for bridges must meet the following requirements:
The total curvature of the beam (rail), determined by the ratio of the maximum bending arrow to the length of the beam
TOPIC № 11 EXPLORATION OF LOW-WATER BRIDGE CONSTRUCTION AREAS AND PROCESSING OF STRUCTURES.
(name of the topic for the program)
METHODOLOGICAL DEVELOPMENT
For group lesson No. 13
(type of occupation)
Exploration of the construction area.
(name of the lesson)
Time -2 hours
Discussed at the meeting of the department
(subject-methodical commission)
"____" ___________________ 2014
Protocol No. ______
Khabarovsk
1. Educational and educational goals: After studying the questions of the lesson, listeners and students should know:
Selection of the bridge alignment;
Identification of the hydrological regime of the river;
Selection of logging sites and locations for the deployment of a point for the preparation of bridge structures.
2.Calculation of working time:
| Lesson content | Time, min |
| Introductory part: Report of the platoon duty officer. Checking the availability of personnel, uniforms, readiness of the platoon for the lesson. Announcement of the topic of the lesson, educational issues and the purpose of the lesson, literature. A short survey on the previously covered topic of the lesson. Give an introduction to the topic. Training questions (main part) 1. Exploration of the bridge construction area. 2. Procurement of bridge structures. 3. Documents processed by intelligence. Conclusion on the topic. Final part: Summing up the lesson. Answers to questions. Checking the quality of assimilation of the lesson material. Self-study task. |
3. Educational and material support:
1.Multimedia ;
2. Educational literature: Military bridge training Military publishing house of the USSR Ministry of Defense 1977. ;
3. Slides on the topic of the lesson.
The purpose of the lesson is to study general information about the exploration of areas for the construction of a low-water bridge and the preparation of structures.
In preparation for the lesson, you must:
Understand the topic and questions of the lesson according to the thematic plan;
Define and understand educational and educational goals;
Select visual aids, technical teaching aids necessary for the lesson;
Think over the course of the lesson in detail, allocate time for working out questions;
Make a lesson plan.
The lesson is held as part of a training platoon using posters and multimedia on the topic of the lesson.).
In the introductory part of the lesson, the presence and readiness of the platoon students for the lesson is checked, the topic and purpose of the lesson are announced, and the studied material is repeated.
In the final part of the lesson, the teacher summarizes the results of the lesson, answers the questions of the cadets and gives a task for self-study.
1. Textbook: Military bridge training, Military publishing house of the USSR Ministry of Defense 1977. ;
2. Textbook: Military road bridges, Military Publishing House of the USSR Ministry of Defense, 1977. ;
3. Textbook "Restoration and operation of bridges on military highways" M. Military Publishing House 1987;
4. Textbook "Technical conditions for the design of military road bridges and crossings" M. Military Publishing House 1974
Topic number 11. Exploration of areas for the construction of a low-water bridge and the preparation of structures.
LESSON #13
Study questions:
1. Exploration of the bridge construction area.
2. Procurement of bridge structures.
3. Documents processed by intelligence.
Exploration of the bridge construction area
Exploration of the bridge construction area
Exploration of the bridge construction area is carried out in order to obtain data providing:
Selection of the site for the construction of the bridge;
Making a decision on the design of a bridge crossing;
Determination of the required materials, forces and means; determination of places for the procurement of materials and the manufacture of structural elements of the bridge;
choice of ways of transportation of materials and structures;
making a decision on the organization of work.
When preparing reconnaissance, the headquarters of the unit should study cartographic, reference and other sources, aerial photography data and reconnaissance data from other branches of the military, characterizing the proposed area for the construction of the bridge. Based on the operational situation and a preliminary study of the sources, the head of the reconnaissance group is indicated:
tentative area for the construction of the bridge;
The type of restoration
Possible recovery methods
reconnaissance tasks with an indication of the sequence of their implementation;
Deadlines for submitting reports.
Intelligence sets:
Bridge construction site;
The profile of the river section, the profile of the banks, approaches to the bridge, the nature of the soils of the river bottom, floodplains and banks, the degree of erosion of the channel and changes in the configuration of the main channel in the area of the bridge crossing;
The speed and features of the current, the slope of the river, the mark of the horizon of low-water and high waters, the high and low horizons of the ice drift;
Estimated navigation horizon, types and dimensions of vessels, rafts and the position of the navigable fairway;
The presence and condition of dams, locks, enclosing dams] on regulated rivers and other hydraulic structures;
availability of materials for the construction of the bridge;
Availability of manufacturing facilities that can be used to manufacture bridge elements and forgings;
Availability and condition of roads in the area of procurement of materials and construction of the bridge;
Necessary camouflage and defensive measures;
the presence and nature of barriers on the water barrier and on the approaches to it.
For reconnaissance, a reconnaissance group is assigned up to a platoon with two officers: the head of the group - an officer (bridge engineer) reconnoiters the barrier, another officer reconnoiters approaches to the bridge, building materials and manufacturing enterprises.
The chosen place of the bridge crossing should contribute to the construction of the bridge in the shortest possible time with the least expenditure of manpower and resources and meet the tactical and technical requirements.
As a result of the reconnaissance of the bridge crossing, | the following documents:
a) a map of the area of the crossing area on a scale of 1:10000-1:50000 or a plan on a scale of 1:10000-1:25000 in size: along the bridge axis - to the high water horizon line plus 100m on each side, along the river - to a double width spill in each direction. With a large width of the river, a plan strip up to 100 m wide above and below the crossing is taken instrumentally in horizontal lines every 1 m; in the rest of the section, the survey is carried out visually. The main axis of the bridge crossing and options, approaches to the bridge, river boundaries with a high water level, areas of the sawmill and construction yard, ways of transporting materials and elements of the bridge, the area of storage of materials at the bridge crossing, as well as available auxiliary enterprises are plotted on the map (plan). and roads to them. The map must have an appropriate legend;
b) longitudinal profile of the transition, indicating all established horizons, as well as geological and hydrogeological data;
c) a diagram of existing or destroyed bridges with basic data on them;
d) field logs (leveling, stationing, goniometric survey, soil surveys and other works, if any, were carried out during exploration);
e) an explanatory note with brief coverage of the river regime, soil and geological conditions, information about existing (destroyed) bridges, data on local building materials and resources, considerations for organizing work, etc.
1.2Selection of the bridge alignment
To determine the points along the width of the river at which measurements of the depths of the river or the velocities of the current are made, in cases where direct measurement of the width of the river with a cable is not possible, the serif method is used (Fig. 1). To do this, the AC basis is broken on the initial bank and the angle β is determined. Then the theodolite is installed on the other end of the basis at point C, from where the angles are measured by notching points 1, 2, ..., n, in which the depth or flow velocity was measured.
Distance from point BUT to the point n determined by the formulas of sines.
If there is a high bank for control, vertical angles are also measured simultaneously if the angle per slope is more than 4 °. The distance to points 1, 2 ... n with an accuracy of 1-2% is also determined by the rangefinder.
Rice. 1. Determination of distances by the serif method
Based on the results of measuring the width and depth of the river, a profile of the living section of the water barrier is drawn. For large volumes of work, the profile is taken using special devices: a PG-48 profiler, an AR-2 river reconnaissance apparatus (at depths up to 5-6 m) and an IREL engineering reconnaissance echo sounder (measured depth up to 20 m).
The removal of the profile by these devices is carried out in accordance with the instructions of the special instructions for the devices.
The slope of the river is determined by large-scale maps with marks of water edges, or by direct leveling of pegs hammered at the edge into the level with the water horizon.
Edged pegs are hammered in characteristic places: at the beginning, middle and end of reaches and rifts; the distance between the cutting stakes should be no more than:
100 m with a channel width of up to 250 m;
200 m 
up to 500 m;
500 m up to 1000 m
If at a distance of 5 km there is a water metering post, then it is desirable to bring the longitudinal profile to it.