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The invention relates to bridge building, and in particular to a method and device for dismantling bridges.
Known patent for the invention of the Russian Federation No. 2250285, IPC E01D 22/00. "Method of replacing the span structure of the bridge". A method for replacing a bridge span, including installation of an existing span to be dismantled on floating supports, followed by disassembly of the span using at least one load-lifting movable crane, loading the disassembled elements of the span onto floating facilities and delivering them to the shore, and erecting a new bridge span , characterized in that during the dismantling of the existing metal through span with belts, braces, racks, suspensions and gussets, before installing the span to be dismantled on floating supports in the alignment of the support nodes of the superstructure, temporary piers are erected and transverse movement of the superstructure to be dismantled is carried out with support it to temporary piers, after which a new superstructure is erected along the longitudinal axis of the bridge and a lifting movable crane is installed on it, and two floating structures are brought under the superstructure to be dismantled which supports, which are located at one of the ends of this superstructure, and the dismantling of the superstructure is carried out from one end of the superstructure to the other with the initial transfer of the load from the superstructure from one of the piers to both floating supports, and as the elements of the superstructure are dismantled, each floating the support located on the side of the dismantled section, after dismantling this section, is moved along the dismantled superstructure and installed behind the second floating support, while the dismantling of the elements of the superstructure is carried out using a crane moving along the erected new superstructure as the dismantling section moves, and the dismantling sections of the existing span are made from top to bottom by first cutting out the linear elements of the upper chord, then the posts, hangers, braces, and then the elements of the lower chord, while the gussets are cut out separately or together with the posts and hangers. When supporting the span to be dismantled on the floating supports, each floating support is anchored. Before cutting out any element of the superstructure to be dismantled, this element is slinged to the crane hook with slings in a loose state. Work on cutting the span structure is carried out from suspended scaffolds. When replacing the span structure of a double-track bridge, work to replace the span structure for the second track is carried out similarly to the work to replace the span structure for the first track.
The disadvantage of this method is that it is quite laborious, requires the construction of additional structures and the involvement of additional equipment, and during the proposed dismantling of the bridge, it is necessary to occupy the bridge space (water area) for a long time.
The closest (prototype) to the claimed invention is a patent for the invention of the Russian Federation No. 2304656, IPC E01D 22/00, "Method of dismantling the three-dimensional blocks of the lattice span of the bridge." A method for dismantling the lattice span of a bridge with three-dimensional blocks with a height of the upper belt above the water level up to 30-35 m and with a span of more than 40 m, including the construction of temporary auxiliary supports at the points of division of the span structure trusses into three-dimensional blocks, the installation of hydraulic jacks on temporary auxiliary supports under the lower nodes of the trusses, their temporary fixation, at least for the period of division, from vertical movement by wedging with steel sheets on the main or auxiliary supports, dismantling of the roadway in the zone of three-dimensional blocks, division into three-dimensional blocks with a length of at least 20 m of the span by cutting or cutting individual truss elements while ensuring the regulation of internal forces in the truss by wedge and / or using hydraulic jacks installed on auxiliary supports within the limits of static loads acting in the truss elements that do not exceed the calculated ones, slinging, release from temporary fixation and dismantling isolated blocks by a floating crane with a lifting capacity of at least 80 tons, moving them to pre-prepared receiving stocks for their disaggregation on the shore and dismantling of temporary auxiliary supports. The division of the farm is carried out initially along the upper, then along the lower belts, starting from the upper plane of the farm. The receiving slipways are placed on the shore, and the disengaged blocks are moved onto them by a floating crane immediately after they are dismantled, excluding transfer to a barge or pontoon. Receiving stocks are placed on the shore, and the movement of isolated blocks on them is carried out by a floating crane after they are transferred to a barge or pontoons.
The disadvantages of this method is the complexity of the additional work performed, the involvement of a large amount of equipment and the long periods of work directly under the superstructure, which prevents the use of the bridge space (water area).
The objective of the invention is the fastest possible removal of the superstructure from its location and the possibility of dismantling the superstructure on the shore.
The problem is solved by installing hydraulic jacks under the lower chord for jacking, after which channels are installed under the lower chord of the beams, then a metal traverse is installed, after that the traverse is combined with the channels, then a pylon is built on the traverse, then the guys are suspended and pulled, after that, the supporting parts of the beams are changed to a movable device, after which the superstructure is pulled out together with the formed prefabricated structure onto receiving stocks located on the shore, and the superstructure is dismantled. The channels under the lower belt of the beams are installed in the longitudinal direction. The traverse is installed along the entire span of the bridge to be dismantled. The traverse and channels are connected by means of vertical rods, followed by welding between them. The pylon is built, for example, in the middle of the span. As a mobile device, rollers or fluoroplastic gaskets are used.
The essence of the claimed invention is illustrated by drawings.
Figure 1 shows a fragment of the existing beam reinforced concrete superstructure of the bridge.
Figure 2 shows a fragment of the connection of the channels installed under the lower chord beams with a traverse.
Figure 3 shows the superstructure of the bridge with installed channels and a traverse along the entire superstructure.
Figure 4 shows the superstructure of the bridge with the installed pylon, channels and traverse, tensioned guys and installed instead of the supporting parts of the beams movable device.
Figure 5 shows shifted at some distance, the superstructure of the bridge with the installed pylon, channels and traverse, tensioned guys and installed instead of the supporting parts of the beams movable device.
The method of dismantling the beam reinforced concrete superstructure 1 of the bridge using the cable-stayed system 2 consists of the following operations: hydraulic jacks (not shown) are installed under the lower chord 3 of the beams 4, then the superstructure 1 is jacked up, after which channels 5 are installed under the lower chord 3 of the beams 4, then a metal traverse 6 is installed, after that the traverse 6 is combined with channels 5, then a pylon 7 is built on the traverse 6, then the guys 8 are suspended and pulled, after that the supporting parts 9 (for example, blocks) of the beams 4 are changed to a movable device 10, after which the superstructure 1 is pulled along with the prefabricated structure 11 formed from beams 4, channels 5 and traverse 6 onto the receiving stocks 12, located on the bank 13, and the superstructure 1 is dismantled (see Fig.1, 2, 3, 4, 5) .
Channels 5 under the lower belt 3 of the beams 4 are installed in the longitudinal direction (see figure 2).
Traverse 6 is installed along the entire superstructure 1 of the bridge to be dismantled. Traverse 6 and channels 5 are combined by means of vertical rods 14 with subsequent welding between them (see figure 2, 3, 4, 5).
Pylon 7 is built, for example, in the middle of the superstructure 1 (see Fig.4, 5).
As a movable device 10 use rollers 15 or PTFE gaskets 16 (see Fig.4, 5).
As a result of the proposed work, the superstructure can be dismantled without the use of lifting equipment and the construction of additional structures.
The use of a cable-stayed system and a prefabricated structure makes it possible to balance the superstructure in such a way that it will not crack, deform, and will not be subject to distortion or shear during the span being pulled onto the receiving stocks.
The problem is solved due to the proposed sequence and combination of works in the proposed method, namely:
1. The superstructure is jacked up with 1 hydraulic jacks installed under the lower chord of the beams (not shown).
2. Install channels 5 with a tight fit to the beam 4.
3. A metal traverse 6 is installed to strengthen the long structure of the superstructure 1.
4. Combine the traverse 6 with the channels 5 by means of a screed with vertical rods 14 and the use of welding.
5. On the reinforced prefabricated structure 11, consisting of beams 4, pulled together by a traverse 6 and channels 5, a pylon 7 is installed.
6. Hang the guys 8, after which they are pulled, thereby strengthening the prefabricated structure 11.
7. Change the supporting parts 9, such as blocks, to the movable device 10, such as rollers 15 or PTFE gaskets 16.
8. The superstructure 1 is pulled out onto the receiving stocks 12 installed on the shore 13.
9. Disassemble the span 1.
Industrial applicability lies in the fact that for the implementation of the proposed method, known equipment is used, which is used in various fields and does not require additional manufacturing and refinement.
All of the above indicates the solution of the problem, namely:
List of positions
1. Superstructure
2. Byte system
3. Bottom belt
5. Channel
6. Traverse
9. Base
10. Mobile device
11. Prefabricated structure
12. Receiving stocks
14. Vertical pull
16. Fluoroplastic gasket
1. A method for dismantling a beam reinforced concrete span of a bridge using a cable-stayed system, including installing hydraulic jacks under the lower chord for jacking and placing receiving stocks on the shore, characterized in that after installing hydraulic jacks and jacking, channels are installed under the lower chord of the beams, then installed a metal traverse, after which the traverse is combined with channels, then a pylon is built on the traverse, then the guys are suspended and pulled, after that the supporting parts of the beams are changed to a movable device, after which the superstructure is pulled together with the formed prefabricated structure onto the stocks and the superstructure is dismantled.
2. The method according to claim 1, characterized in that the channels under the lower chord of the beams are installed in the longitudinal direction.
3. The method according to claim 1, characterized in that the traverse is installed along the entire superstructure of the bridge to be dismantled.
4. The method according to claim 1, characterized in that the traverse and channels are combined by means of vertical rods, followed by welding together.
5. The method according to claim 1, characterized in that the pylon is built, for example, in the middle of the span.
6. The method according to claim 1, characterized in that rollers are used as a movable device.
7. The method according to claim 1, characterized in that PTFE gaskets are used as a movable device.
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In 1964, a bridge across the Don River in the city of Aksai was put into operation. The city of Aksai is located in the suburbs of Rostov-on-Don, on the steep right bank of the Don, at the confluence of the Aksai River, which is an arm of the Don (Fig. 1).
The bridge crossing is located at km 1061+570 of the motorway 1 category M-4 "Don" Moscow - Voronezh - Rostov - on - Don - Krasnodar - Novorossiysk.
The bridge was built in the period from 1958 to 1964 according to the project of the Tbilisi branch of Soyuzdorproekt under the loads H - 18 and NK - 80. The fundamental design document "Rules and indications for the design of reinforced concrete, metal, concrete and stone artificial structures on highways" edition of 1948 G.
The design of the superstructure was developed by the Institute "Proektstalkonstruktsiya". The project for the installation of the bridge span was developed by the Prometallkonstruktsiya Institute in Moscow.
There are five spans in the bridge crossing scheme, covered by a continuous steel-reinforced concrete span structure according to the scheme 65.59 + 126.0 + 147.0 + 126.0 + 65.59m. The total length of the structure is 545.83 m (Figure 2). The width of the bridge between the railings is 10.02 m. The main beams are welded with bolted field joints.
In bay 1-2 there are two main tracks of the electrified railway and one dead-end track. (Figure 3).
Bridge span 3-4 is navigable with heavy traffic. The ship's passage in the area of the bridge belongs to the seaport "Taganrog".
Bridge clearance from the water surface 19.8 - 21.5 m, from the rail head 13.5 m.
During operation, repeated surveys and tests of the superstructure were carried out. The last survey at the pre-project stage of reconstruction was carried out in 2007 by MGUPS (MIIT), which provides a detailed description of the main results of previous surveys, basic information about the operation of the facility and repair activities that were carried out during the operation period.
The occurrence of significant defects during the period of operation in the elements of the structure is associated with two circumstances: with the overload of the superstructure with constant loads from excess layers of road pavement; the movement of support No. 1, which was caused by landslides on the slope of the right bank of the Don River.
During the construction of the bridge from 1958 to 1964, work was carried out that introduced many uncertainties into the overall stress-strain state of the structure and greatly complicated the assessment of the technical condition of the bridge. At the final stage of the design, the roadway size was increased from G-7.0 to G-8.0 without changing the design solutions of the main metal structures. In order to improve the longitudinal profile, an additional layer of concrete of variable thickness was laid at the supports in the span of 147 m, as well as in the outer spans. The longitudinal profile of the upper chords of the main beams and the roadway slab during the construction period was corrected by laying an additional layer of concrete and asphalt concrete on the roadway slab in the places of “failures”. For this purpose, a layer of variable thickness with a total volume of about 170 m3 was added in spans 1-2, 3-4, 4-5.
In the course of repeated studies and measurements of the stress-strain state of steel beams, it was determined that in sections above supports 3, 4 and 5, the stresses in the upper chords of the beams exceeded the calculated ones. The magnitude of the overvoltage, approximately, reaches 15 - 20% (data from VISI, TsNIIS, Institute "IES Paton").
In 2010, the RTF "Mostootryad-10" carried out work to eliminate the emergency at the bridge crossing, the work consisted of the following:
- trimming the ends of the metal structures of the span, the ends of the spans were rested against the cabinet wall;
- lifting of the superstructure with adjustment of the position of the supporting parts on support No. 1;
- installation of supporting structures under the sidewalk blocks in the navigable part of the bridge in order to keep them from spontaneous collapse. The supporting consoles of the sidewalk blocks were in a state of disrepair, the blocks were held by railings and resting against each other.
Based on the report of MGUPS (MIIT), a decision was made to dismantle the bridge.
The superstructure is steel-reinforced concrete beam-continuous. In cross section, the superstructure consists of four main beams of I-section of variable height. The distance between the main beams is 2.4+3.0+2.4.
The material of the main beams and jacking beams is 10G2SD, ties and other elements from St3. Welding of elements from low-alloy steel was carried out automatically, field connections were made on rivets with a diameter of 23 mm from steel 2, 26 mm from steel NL-1.
The main beams are interconnected by a precast-monolithic reinforced concrete slab of the roadway, longitudinal (in pairs of beams 1 and 2, 3 and 4) and transverse braces. The main beams in the end spans at the extreme supports have a height of 2.5 m. On the rest of the end spans, the height of the beams gradually increases and on the supports reaches 4.6 m. In the middle part of the three main spans, the height of the beams is 2.5 m. On the supports of the middle span, the height of the beams 6.549 m. (Fig.4).
Steel main beams above supports 2, 3, 4 and 5 are prestressed at the level of the upper chords by bundles of high-strength wires. Tensile strength of wires R=17000 kgf/cm2. Bundles of high-strength wire are made in the form of cables of three strands of seven threads of 0.5 mm and three separate wires of 0.5 mm. The tension of the beams was carried out by double-acting jacks, after which the beams were fixed with the help of anchor plugs and blocks on special stops welded to the upper chords of the beams.
The length of the prestress zone above supports 2 and 5 is 51.5 m, and above supports 3 and 4 is about 103.4 m.
The beams are monolithic when concreting the roadway slab.
The roadway slab consists of three types of precast concrete slabs. The thickness of the slab is 15 cm, made of concrete grade 350. The slabs are monolithic along the upper chords of the main beams with concrete grade 400. For joint work, the main beams are combined with reinforced concrete slabs using stops. The stops are made of sheet steel.
Elevated sidewalks, arranged in sidewalk blocks. Fastening of paving blocks is carried out for ledges in prefabricated slabs and for the edges of the consoles of the carriageway slab.
The main bridge disassembly sequence proposed at the “P” stage was as follows (Fig. 5):
— The superstructure in span 1-2 is being dismantled by the railway. crane in the "window" of railway traffic, span 4-5 and 5-6 is dismantled using a truck crane with a lifting capacity of 100 tons or more, in span 2-3 and 3-4 by a floating crane. Dismantling of outdoor lighting poles, barrier and railings and sidewalk consoles, starting from the middle of the spans to the poles using a crane with removal by vehicles;
— Removal of the asphalt concrete pavement of the roadway, starting from the middle of the spans to the supports;
– Dismantling of the protective layer and waterproofing, starting from the middle of the spans to the supports;
– Dismantling sections of the roadway slab in the summer with a crane, sawing them into a size of 3 * 3 m, followed by laying a wooden flooring from a beam for the movement of equipment. Dismantling is carried out simultaneously in spans 2-3, 3-4, 4-5 from the middle of the span to supports 3, 4 and 5.
– Installation of temporary supports in span 1-2 and 5-6;
— Dismantling of the remaining part of the roadway slab. The beams are dismantled simultaneously with the dismantling of the span blocks.
— Installation of temporary supporting supports near supports 3 and 4. Balanced dismantling by crane MDK 63-1100 afloat, starting from the opening of the locking section in span 3-4.
- The dismantling of span 1-2 is carried out by the crane EDK - 1000, with the installation of a temporary support, into the "windows" with the crane rearranged along different paths. The extreme block is dismantled by a truck crane from the approach.
The main reasons for rejecting the proposed option for dismantling the bridge spans at the "P" stage were:
- poor elaboration of the method of work execution by the design institute, the absence at the "P" stage and the failure to provide further calculations confirming the correctness of the decision;
- at the stage "P" the general stress-strain state of the structures of the bridge span was not taken into account;
— use of floating cranes when dismantling the span, which is difficult given the intensity of vessel traffic within the water area of the seaport;
— dismantling of span 1-2 of the railway crane with a significant workload of the main course of the Moscow-Rostov-on-Don-Adler direction, as well as the absence at the “P” stage of the costs for the reconstruction of Russian Railways communications when operating with an EDK-1000 crane.
Figure 5. The general sequence of dismantling the bridge crossing at stage "P".
The main scheme for the dismantling of superstructures at stage "P" is as follows (Fig. 6):
- dismantling in spans 4-6 is carried out by a self-propelled jib crane with the installation of temporary supports to support the span in the cut zones. Temporary supports on a natural base are made of inventory structures MIK-S and MIK-P.
- dismantling in spans 2-4 is carried out from the interlock section in span 3-4 (mid-span 147 m) in both directions to supports 2 and 4 by UMK-2 cranes installed and moving along the rolling tracks on the haunches of the upper chords of the beams of the span along the beams 1 and 4. The dismantled structures are lowered onto the floating system and moved to the pier for unloading.
- dismantling in span 1-2 is carried out by two cranes, from the interlocking section towards support 2 by a DEK 321 crane installed on the site in the area of support 2 and from the interlocking section towards support No. 1 by a Liebherr LTM1100 jib truck crane installed on the carriageway of the span. To dismantle span 1-2, temporary supports are installed from structures MIK-S and MIK-P in span 1-2 and 2-3. The extreme block to support 1 is dismantled by a truck crane from the approach.
Dismantling at all stages is carried out one beam at a time in the following sequence, first two extreme beams are dismantled in turn, then two middle ones. The sequence of dismantling the outer and middle beams is assigned in the PPR from the convenience of working with a crane and a floating system.
Preliminarily, along the length of the block, work is carried out to dismantle the longitudinal and transverse braces, install a temporary railing along the upper chords of all beams, suspend all sets of rigging and scaffolding for cutting.
Fig. 6. The adopted scheme for the dismantling of the bridge crossing at the stage "P".
In order to make a final decision on the dismantling of the span structures of the bridge and analyze the state of the structures of the span structure, at each stage of disassembly, ZAO Scientific and Design Institute IMIDIS, under an agreement with OAO Giprotransmost, monitored the stress-strain state of the structures.
Main stages of work:
– determination of the initial stress in the metal structures of steel beams;
— carrying out static tests;
– installation of a monitoring system and removal of zero reports;
— carrying out monitoring with data recording in the database.
The monitoring report was available on a permanent basis via the Internet through the KIS-control program IMIDIS.
In the course of the work, on a daily basis, the engineer of the RTF "MO-10" transferred to the design institute a scheme for conducting work on the dismantling of the elements of the bridge. The design institute compared the monitoring readings and the results in the course of the work, on the basis of which adjustments were made in the scheme for dismantling the roadway slab and haunches, i.e. adjustment of the constant load located on the superstructure at the stages of the beginning of the dismantling of the s.c. span structure and subsequent stages.
The dismantling of the carriageway and the bridge deck, basically, does not differ from the “P” stage. At the first stage, the asphalt concrete pavement is dismantled at a distance of 20 meters in the middle of the spans, then the barrier fence is dismantled along the entire length of the bridge. Next, the rest of the asphalt concrete pavement is cut with a milling cutter weighing no more than 35 tons in strips of 2 m and dismantling of the protective layer, waterproofing, leveling layer in strips of 2 m, lagging behind the cutter by a span (Fig. 7).
Figure 7. Dismantling of the roadway and bridge deck at the "P" stage.
The dismantling of paving blocks was carried out from the middle of span 3-4 in both directions from the upper and lower sides simultaneously. Dismantling in the navigable bay was carried out during breaks in the movement of ships, in connection with the port dispatcher, and in bay 1-2 through a blind "window" with the removal of voltage in the contact network. Due to the emergency condition of the supporting consoles of the roadway slab, on which the sidewalk block is installed at one edge, scaffolds were made of individual metal and IPRS elements for safety during the period of work (Fig. 8).
Figure 8. Dismantling of paving blocks. SVSiU for disassembly of paving blocks.
The sequence of dismantling was as follows: supporting scaffolds were brought under the dismantled blocks, then the block was attached to the supporting consoles, only after that the railing was dismantled along the dismantled block, the installation of slinging holes, slinging the block, cutting the block from the mortgage, dismantling the block with a crane with loading on a dump truck and installation of temporary railings. Further, by analogy, the shifting of scaffolds, etc.
The dismantling of the roadway slab and haunches was carried out in accordance with the sequence developed by Giprotransmost OJSC, this sequence, first of all, took into account the stress-strain state of the structures of the bridge span, as well as the accepted technology for dismantling the spans (Fig. 9).
Figure 9. Disassembly of the roadway slab. Performance of works of a longitudinal cut of section of a plate by the HILTI hydraulic wall saw machine.
To carry out work on cutting and dismantling of the slabs, supporting structures installed on the upper part of the slab were manufactured and applied in parallel.
The sequence of works for the dismantling of the plates is as follows:
- drilling holes for the installation of supporting structures;
— installation of supporting structures;
– cutting the slab along the haunch with circular saws, from seam to seam of a prefabricated monolithic slab 2.62 m; - dismantling of the slab with a crane; - flooring device instead of the dismantled slab. The work was carried out simultaneously at several points and spans.
The haunches were dismantled with jackhammers, a non-explosive mixture of HPC, concrete breakers, etc.
Taking into account the least complexity and the least amount of preparatory work in comparison with the channel spans and span 1-2, as well as the decision to change the method of installation of the metal structures of the span by the method of conveyor-rear assembly and sliding from support No. 6, the floodplain spans 5- 6 and 4-5. Dismantling was carried out by a Liebherr LR 1130 caterpillar crawler crane with a capacity of 130 tons. Dismantling was carried out along one plane of beams with haunches and with dismantled haunches. The preparatory work included the dismantling of longitudinal and transverse braces, the installation of slinging devices and the temporary unfastening of the beams. During dismantling, special attention had to be paid to securing the fourth beam in order of dismantling. The dismantling of the third and fourth beams in order of dismantling was planned with the least interruption and constant control of the wind control according to the forecast and directly with an anemometer on site.
The section of span 4-5 from support 4 to temporary support VO1 was dismantled last of all, since its dismantling was linked to the dismantling of span 3-4 by the UMK crane, the span was a weight for part of span 3-4, and was also used for parking (when dismantling the latter block), movement and dismantling of the UMK crane.
The dismantling of the channel spans was carried out using a UMK-2 crane installed on the haunches of the upper chord of the outermost beams of the span. Crane stations were selected mainly based on the weight of the dismantled element and the vertical stiffener of the superstructure for attaching the crane. Prior to the dismantling of the central block, two temporary supports were installed in bay 3-4, on piles in bay 2-3, and two temporary supports in bay 4-5 on a natural foundation. Temporary supports are made of inventory bridge structures MiK - S and MiK - P. In span 2-3, temporary supports are connected to each other by a spacer in the upper level and with support No. 3 at the level of the support No. 3 layer.
Prior to the start of work on cutting the interlock section in span 3-4, work was completed at all previous stages, in accordance with the general sequence of work:
— dismantling of the roadway and sidewalk blocks;
- sub-blade of temporary supports in span 2-3 and 3-4;
Dismantling at a distance of 75 m of the roadway slab in span 3-4;
— dismantling of haunches in bay 3-4 on a section of 40 m in bay 3-4;
- installation of two cranes UMK - 2 and their installation above supports 3 and 4;
- wedge of the movable support part on the support 3.
Immediately before the work was carried out:
– installation of a frame with lifting cradles for section cutting;
- dismantling of longitudinal and transverse ties at the place of the cut;
- the order of cuts was marked.
Facade lifts were purchased for the execution of works on cutting span structures. The main criterion for choosing facade lifts is the significantly varying height of the vertical wall of the beams from 2.5 to 7 meters. Four facade lifts installed on a common frame moved along the rolling paths of the UMK crane (Fig. 10).
Figure 10. Cutting the superstructure using facade lifts.
The interlock section of the span structure was cut simultaneously along all four beams in accordance with the scheme issued by the design institute. According to the calculations of the designers, the superstructure should remain close to the existing position after opening or move up by an insignificant amount, which was confirmed by the monitoring data of the IMIDIS Institute.
After the interlock section was cut, the central blocks of span 3-4 were dismantled with two UMK cranes during breaks in the movement of ships. One crane dismantled towards support No. 3 and further to support No. 2, the other towards support No. 4. To reduce the duration of the “windows”, a significant amount of preparatory work was carried out:
— installation and fastening of UMK cranes; — dismantling of longitudinal and transverse links; — installation or shifting of the frame with facade lifts;
- installation of scaffolds for slinging along all beams;
- installation of rigging facilities for all beams;
— installation of safety pads and cutting beams of the superstructure.
In the process of carrying out the "windows", the beams were directly slinged, the safety straps were dismantled and the dismantled beam was lowered onto the barge.
Equipment used for cutting: high-strength cutter type NORD-S and air-plasma cutting unit UVPR2001 with plasma torches PRV 301 and VPR 405.
The sequence of cutting proposed by the institute is as follows: making longitudinal cuts with a step of 100 mm at a distance of 400 mm from bottom to top, then cutting across the joint from bottom to top with opening along the upper chord.
Before and during the work, changes were made to the order of cutting due to technology, the placement of scaffolds on one side (window cutout) and a decrease in the amount of striping of the vertical wall in the zone of zero moments (window cutout along the vertical wall). The device of a transverse cut with a strip 5-7 cm wide and the final opening in the lower part of the wall (Fig. 11).
Rice. 11. The final section of the lock cut.
Fig. 12. Dismantling of the central "lock" blocks by UMK-2 derrick cranes in the channel span 3-4
In the course of making a decision on the method of dismantling span 1-2, various options were considered (use of an EDK 1000, KShK crane, installation of a jib crane with a capacity of 130-200 tons at support 2, etc.). The implemented option provides for the dismantling of the beams with two cranes from the interlocking section in different directions (Fig. 13, Fig. 14). The main stages of the work were as follows:
— installation of three temporary supports;
- jacking up the span on a temporary support 2, creating the necessary effort;
– installation of counterweights over temporary support 3
; - opening of the interlock section in span 1-2; - dismantling of beams with the performance of work by analogy with spans 2-4.
The main difficulty in performing the work was the possibility of providing "windows" in the movement of the railway. transport, duration from 45 to 90 minutes including the work of ECHK and IF.
The cutting of the interlock section was carried out by analogy with the span 3-4, except for the change in the design of the scaffolds associated with the presence of the railway. and the order of cut associated with the predicted downward movement of the superstructure.
Fig. 13. Dismantling of the span structure of the bridge crossing in span 1-2 by a DEK-321 crane, in the right of way of the railway.
Fig. 14. Dismantling of the span structure of the bridge crossing in span 1-2 by a LIEBHERR LTM-1100 crane.
The development and execution of work on the dismantling of the bridge crossing using various methods of work with maximum accuracy, in a short time, near the existing bridge crossing became possible thanks to the well-coordinated work of engineers, employees of the Mostootryad-10 RTF, as well as specialists from Giprotransmost JSC, the Institute "IMIDIS".
Demolition and dismantling of bridges and overpasses- a separate, most difficult direction of dismantling.
The task of dismantling bridges in Moscow and their subsequent complete replacement is very relevant in our country, because. a huge number of such objects are in a deplorable state, have lost their bearing capacity.
Dilapidated, old bridges and overpasses are subject to as soon as possible dismantling and dismantling.
Construction and Investment Company provides a full range of services for demolition and dismantling of bridges and overpasses in Moscow and the region, starting from the preparation of the relevant documentation, ending with the production of all necessary work and the commissioning of the facility. We comply with all necessary building codes and regulations, guaranteeing excellent quality of work and quick results.
The dismantling of bridges and overpasses is a very difficult task that requires a special approach and specialists with the appropriate qualifications. It requires coordinated actions of engineers, builders, dismantler. Our company employs all the necessary specialists, including. You can be sure that you are trusting the construction site in the reliable hands of professionals.
Our organization is ready to carry out the dismantling of the following types bridges:
- wooden bridges
- Reinforced concrete bridges
- metal bridges
When any violations appear during the operation of the bridge, it is necessary to immediately begin dismantling. Also, this procedure will have to be started at the end of the service life. This type of work is carried out with the help of explosive devices, or mechanical and technical means. Existsa number of factors, with which you can determine the type of work required:
Bridge structure size;
Features of its coverage;
Production material;
The actual location of this bridge;
Availability of a detour road;
Ability to approach the bridge using heavy equipment.
Order the demolition of the bridge
Would you like to order the demolition of the bridge, the liquidation of the overpass? Call us by phone in Moscow, or send a request to our e-mail box - we are always in touch, we will call you back in a matter of minutes!
During the period of its existence, the specialists of our company have developed and implemented more than 10 successful projects for the dismantling of bridges and overpasses of various lengths, this allows us to declare that we have considerable experience and seniority.
Construction and Investment LLC has all the necessary equipment and special equipment for dismantling of bridges and overpasses different lengths and designs.
We carry out our activities for the dismantling of bridges not only on the territory of Moscow and the Moscow Region, but also on the territory of all subjects of the Russian Federation.
You can apply for the dismantling of bridges and overpasses using the feedback form or simply call us.
The dismantling of bridges is in demand today along with the demolition of buildings. The reason is that many structures have long served their time and require replacement, and given that the bridge is a dangerous structure, its replacement and repair must be done without delay, especially when it comes to transport bridges: road, railway, metro bridges . Constant fluctuations, external natural influences and regular operation wear out the structure, due to which it loses its strength and reliability.
How are bridges demolished?
Depending on the design, size of the bridge, the main material from which it was built and the characteristics of the road surface, the dismantling of bridges can be carried out in several ways: explosive, mechanical and technical. In addition, his choice is also influenced by the physical condition of the bridge, the presence of detours and the surrounding traffic conditions: whether partial traffic continues on the bridge or the bridge is not currently in full use.
As a rule, explosive dismantling of a bridge is used for monolithic structures, and dismantling with disassembly of the structure into individual elements is preferable for prefabricated bridges. The blasting method is used only when it is possible to fence off the dangerous area for access and passage and blasting will not harm the environment. If this is not possible, then the dismantling of bridges is carried out manually or mechanically using special tools and heavy equipment, such as laser cutting.
The dismantling of steel bridges is carried out using auxiliary supports and scaffolds, the bridge is disassembled in large parts. Cranes, self-propelled modular carts, jacking and rigging systems, barge platforms, etc.
The simplest situation is with the dismantling of wooden bridges with low bearing capacity. Such demolition of the bridge can be carried out with the help of cable traction using a cable winch or by dismantling. Today, wooden bridges are rarely built, their service life is very short - only 10-15 years. They are used only as temporary structures.
With the greatest care, the dismantling of the bridge thrown over the reservoir is carried out: all work must be done carefully, completely eliminating the ingress of construction debris into the water. For this, modern and efficient technology of diamond cutting with discs and wire is used, which makes it possible to easily deal with concrete, reinforced concrete, monolith with a minimum amount of construction debris.
Connecting elements and reinforcement elements for turning beam-slit spans into a continuous system should be designed based on their simple, safe and reliable dismantling.
The connecting elements and reinforcement elements are dismantled, starting with the operation of removing fasteners in nodes and connections only if there are no axial forces in them, preventing simultaneous disassembly of several main truss nodes (or branches).
The elements are unloaded by jacking up the mounted superstructure on the support. The procedure for dismantling the connecting elements and reinforcement elements must be specified in the project for the production of works. The dismantling of the connecting elements is classified as particularly complex and must be carried out with the participation of the installation manager.
For typical superstructures, inventory reusable connecting elements and reinforcement elements should be used. When dismantling, it is necessary to apply measures for their safety.
When dismantling the connecting elements and SVSiU, the order of removal of structures specified in the PPR must be observed. In the dismantled elements at the level of the center of gravity of the section, there should be no effort from the weight of the mounted superstructure. Jacks, lever winches and other means of movement should be used when removing elements suspended from a crane hook from knots and connections. Dismantled elements should be laid on the ground, on floating or vehicles, ensuring their stable position.
The execution of especially critical operations during hinged, semi-mounted and balanced-mounted mounting should be supervised by the manufacturer of the installation work, appointed by order of the bridge building organization. Particularly responsible operations include:
Raising and lowering span structures with hydraulic jacks with installation on supporting parts;
Selection of the deflection of the console with the support of the superstructure on the next support;
Dismantling of connecting elements between split span structures;
Closing the span in the middle of the span during installation from both banks;
Balanced mounting.
If necessary, the organization carrying out the installation develops production instructions to ensure labor safety.
In order to prevent environmental pollution, the following measures should be taken:
The assembly site, including a warehouse for metal structures, stands for pre-assembly and welding of assembly elements, amenity and industrial premises should be located outside the water protection zone;
Access roads and the installation site itself must be covered with precast concrete slabs laid on a sandy base, without damaging the soil layer;
Crane overpasses and working bridges in the water area of watercourses or reservoirs should be erected according to projects agreed with the water and fish protection authorities;
The bases of temporary supports for semi-mounted installation should, as a rule, be made of driven metal pipes without excavation of soil from the cavities.
After the completion of construction and installation works, all temporary structures in the riverbed and on the site must be dismantled, and the riverbed and banks must be brought to the state specified in the master plan of the bridge structure.
2. Dismantling of connecting elements
Dismantling of connecting elements split spans with (Fig. 6.30) is made only when the values of the forces in these elements are brought to zero.
Rice. 6.30 - Schemes for the dismantling of connecting elements
This is achieved by jacking up the end of the span by the value Δ, when the angle in the vertical plane between adjacent spans will be equal to zero, i.e., if the mutual angle of rotation of the ends of the span during their deflection from their own weight when the profile of neighboring spans is fractured will be equal to zero. To do this, the amount of jacking of the end of the span should be equal to 2Lφ where φ is the angle of rotation of the end of the span with a span of length L when it is loaded with its own weight.
The amount of jacking can be quite large, for example, with a span of 100 m, it is possible to lift the end of the console by 80 cm.
Mounting cranes for suspended mounting, these are jib full-slewing cranes, as well as rigid-legged derrick cranes with a lifting capacity of up to 20 tons with a boom length of about 20 m, moving along the upper chords of trusses. Before installing the element, the cranes (Fig. 6.31 and 6.32) are anchored behind the chords of the trusses of the assembled superstructure.
Rice. 6.31 - Derrick-crane MDK-63-1100: I, II, III, IV - possible schemes for the position of crane runways (scheme IV - with equal dimensions of track A and base B)
Figure 6.32 - Derrick-crane UMK-2 on the upper chords of the mounted superstructure: 1 - truss axis; 2 - the upper belt of the farm
Non-rotary cranes are used, the angle of rotation of the boom in the plan reaches 240–260 ° when the crane is supported at three points (at the base of the mast and lower strut braces) and up to 160–170 ° when the crane is installed on a horizontal frame of a rectangular truss.
When dismantling the connecting elements and SVSiU, the order of removal of structures specified in the PPR must be observed. In the dismantled elements there should be no effort from the weight of the mounted superstructure. When removing the elements suspended from the crane hook from the nodes and connections, jacks, lever winches and other means of movement should be used. The dismantled elements should be laid on the ground, floating or vehicles, ensuring their stable position.
connecting elements for the transformation of beam-slit span structures into a continuous system should be designed based on their simple, safe and reliable dismantling.
The connecting elements are removed, starting from the operation of removing the fasteners, only if there are no axial forces in them.
The elements are unloaded by jacking up the mounted superstructure on the main support. The procedure for dismantling the connecting elements must be specified in the project for the production of works. The dismantling of the connecting elements is classified as particularly complex and must be carried out with the participation of the installation manager.
For standard spans, inventory reusable connecting elements should be used. When dismantling, it is necessary to take measures for their safety.
When dismantling the connecting elements and SVSiU, the order of removal of structures specified in the PPR should be observed. In the dismantled elements there should be no effort from the weight of the mounted superstructure. When removing the elements suspended from the crane hook from the nodes and connections, jacks, lever winches and other means of movement should be used. The dismantled elements should be laid on the ground, floating or vehicles, ensuring their stable position.
Source: http://www.gosthelp.ru/text/STP00497Navesnojipolunave.html
Complex mechanization of assembly (dismantling) of building structures during the reconstruction of buildings and structures has some features, consisting in the parameters of the external and internal constraint of the object and the need to replace or strengthen existing structures. During the installation of building structures during the reconstruction of buildings, some manual operations are required, for example, when passing prefabricated elements through obstacles, arranging interfaces with existing structures. This must be taken into account when choosing the means of complex mechanization of installation work to ensure the continuity of the technological process.
In domestic practice, the method of large-block installation with preliminary enlargement of structures is widely used. Enlargement of individual structural elements into mounting blocks can significantly reduce the amount of labor-intensive and dangerous work at height, reduce the cost of constructing temporary scaffolds, supports, etc., improve working conditions and improve the quality of work. The optimal degree of enlargement of structures should be determined by technical and economic calculations. At. At the same time, the dimensions of the mounting blocks during the reconstruction of buildings and structures should be compared with the parameters of the object's constraint.
A prerequisite for the effectiveness of the methods of reconstruction of objects in general is the industrialization of the dismantling of building structures. Dismantling work is quite difficult to mechanize. The task is to ensure that the dismantling of structures, if possible, is carried out using block methods, using all the materials obtained during the processing of dismantling blocks.
The main methods of installation of building structures during reconstruction are determined by: tightness parameters; the possibility of using mounted blocks to move assembly machines along them; types of mounted structures; the degree of wear of existing structures; the order of assembly of floors; technological conditions.
The technological sequence of assembly and dismantling of structures predetermines the organization of work according to separate or complex schemes.
With a separate scheme, at the first stage of the technological process, all structures to be replaced within the facility are dismantled, and then new ones are mounted. In this case, dismantling and installation can be done using different machines. A separate scheme is used in conditions where the dismantling of structures does not threaten the collapse of adjacent elements or the overall stability of buildings. Its advantage is the possibility of using powerful mounting machines. However, it is often necessary to perform a large amount of work to strengthen structures and ensure the overall stability of the building. The possibility of combining the execution of subsequent works is also somewhat limited.
The complex scheme provides for the combination of dismantling and installation of structures in compliance with conditions that ensure sufficient strength, rigidity and stability of adjacent structures and the structure as a whole. The scheme provides for the successive replacement of structures in grips, sections and cells. Assembly and disassembly work is carried out using the same set of machines. At the same time, the front is opened for subsequent work, as a result of which the overall reconstruction time is reduced.
Currently, installation organizations have a wide range of serial lifting machines. However, under the conditions of reconstruction, such characteristics of the means as their mobility, overall dimensions in the transport position and dead weight, ease of re-equipment, the ability to maneuver with a load on the hook in a limited space, etc. are essential. Our industry does not yet produce technologically specialized cranes for reconstruction conditions. Therefore, it is necessary to use existing serial lifting mechanisms.
The most widespread during the reconstruction are self-propelled jib cranes, including automobile, pneumatic-tired, caterpillar and, less often, railway ones. This is due to relatively low costs for transportation, installation and dismantling, as well as relatively high maneuverability.
However, the ability of self-propelled jib cranes to move with a load, unlike tower cranes, is very limited. Therefore, the structures to be mounted, prior to the installation, must be laid in a specially designated place, taking into account the installation parking of the crane, its load capacity, boom reach and the place where the structures are installed in the design position.
Occupancy of the area of the reconstructed spans by existing lifting structures often does not allow this requirement to be met, which causes additional costs for sorting structures, arranging special entrances, supplying structures under the hook using auxiliary transport vehicles (transport trolleys, tractors, etc.).
When organizing installation work in cramped conditions, it is desirable to carry out the installation of building structures from vehicles. This will reduce the areas allocated for storage of structures, reduce unproductive machine time of erection cranes, reduce labor intensity and reduce the time of work.
The efficiency of using self-propelled jib cranes during the installation of attached, built-in and connecting spans increases when they are equipped with tower-jib equipment, which provides greater freedom of maneuver when turning the boom and its longer reach. The use of such cranes allows the installation of structures from parking lots located outside the cramped erected spans, and provides significant cost savings in preparing the site for production.
The scope of self-propelled jib cranes during reconstruction also increases when they are equipped with telescopic jib equipment. The small dimensions of such cranes in the transport position, quick bringing to working condition, ease of changing the length of the boom create favorable conditions even in the production of in-shop installation work.
TsNIIOMTP has developed equipment for the MKG-6.3 crane, which is a hinged parallelogram mounted on the crane turntable instead of the boom with a retractable jib in the form of the upper link of the parallelogram.
The lifting capacity of the crane, depending on the angle of inclination of the parallelogram to the horizon, is from 2.7 to 3.2 tons, the outreach is from 2.06 to 8.96 m, the lifting height of the hook is up to 7.6 m. hard-to-reach places for a conventional jib crane, provides separate horizontal and vertical movement of goods, facilitates the passage of the crane under obstacles.
On some cranes (for example, SKG-30) special types of booms with forked caps are used to lift high columns lashed above the middle and placed inside the forked boom head. This design of the boom makes it possible to reduce the reach and lifting height of the hook required for given columns and use a crane with a lower lifting capacity, and also creates favorable conditions for the installation and dismantling of columns, while limiting the height clearance by existing structures and communications.
One of the ways to improve the technological capabilities of jib cranes is the use of additional inventory devices that can take on increased loads (“derrick effect”). So, for example, it is advisable to use a chevre device in combination with crawler cranes with a lifting capacity of 25, 40, 63 and 100 tons for the installation of large-sized structures and equipment, the mass of which exceeds the nominal lifting capacity of the crane. Its application allows to increase the lifting capacity of the crane by 1.5-3 times. The use of a chevrolet device in the conditions of reconstruction makes it possible to mount heavy structures when transporting more powerful cranes to the facility is not feasible or inefficient.
There are also other proposals for using the "derrick effect" to increase the lifting capacity of jib cranes.
Tower cranes are used less often in the reconstruction of workshops than in the construction of new facilities. This is due to an increase in unit costs for the installation of crane runways, installation and dismantling of the crane, with increased crampedness of the installation area, which limits the possibility of delivering the crane to the construction site. However, the verticality of the crane tower and the high suspension height of the jib make it possible to move the erected structures above the existing ones and place them even in the narrow corridors formed by the existing buildings.
The invention relates to bridge building, and in particular to methods for dismantling metal superstructures of a bridge (trusses), and can be used in the overhaul of a bridge on highways under construction or in operation.
Various dismantling methods are used to replace old span structures that have served their time. This takes into account, first of all, the technical condition of the span structures and local conditions. It would seem that the easiest and most logical thing to do in terms of the working conditions of the structures is to dismantle in the reverse order to the installation, which was used in the construction of the bridge. But this is practically not done due to the lack of initial design data, changes in the structure itself (especially in the nodal connections), changes in the operating conditions of the structures during the long-term operation of the bridge. Of particular difficulty is the dismantling and dismantling of span structures of a lattice structure.
A known method of dismantling the superstructure of the bridge, which includes assembly preparation for removal and removal of the superstructure. What is new is that the cutting charges are preliminarily installed in the cross section of each beam, located in the section of one of the two transverse planes symmetrically removed from the central vertical axis of the superstructure, the detonator is installed by means of at least three times duplicated detonating cords, and ramps with the possibility of movement of the side parts along them under the action of mechanical impulses, while the removal is carried out by in-phase cutting by the method of explosive shears of the cross sections of the span beams in the indicated planes (RU No. 2171872 C1, E01D 22/00, 2001).
Of the known, the closest is the method of dismantling the lattice superstructure of the bridge, in which on rail tracks laid on both banks perpendicular to the axis of the bridge, collapsible mobile frames are installed under the dismantled superstructure, on which collapsible towers, cargo crossbars, clamps are mounted - limiters, on which hydraulic jacks are installed and fixed (DG-175 brand with a rod stroke of 1100 mm), guide rods, in which upper, lifting beams are installed with their hinged support on the heads of hydraulic jack rods. On prefabricated mobile frames, lower lifting beams are installed, located across the span with lower lifting beams passed through them, located along the span. The upper lifting beams are combined with the lower lifting beams with load-bearing holes with tapes using rods. The lower lifting beams located across the span are gradually raised by hydraulic jacks until they come into contact with the superstructure, and then the superstructure is raised to the required height. The rods of the hydraulic jacks are raised by 750-1000 mm and when the holes in the cargo crossbars are aligned at this height with the holes in the cargo belts, the rods are installed in the latter. After that, the hydraulic jacks are recharged for the next rise. The hydraulic jack rods are lowered initially by 10-15 mm until the rods are released and removed from the holes in the upper lifting beams and cargo belts. Next, the rods of the hydraulic jacks are lowered together with the upper lifting beams to the lower position and the holes in the cargo belts and in the upper lifting beams, in which the rods are installed, coincide. At the end of the reloading of the hydraulic jacks, the next rise is made by 750-1000 mm, while initially the rise is made by 10-15 mm until the rods are released and removed from the holes in the cargo crossbars and in the cargo belts. The superstructure lifted from the supporting parts is fixed by installing the rods in the holes in the cargo crossbars and in the cargo belts and moved on the device along the rail tracks to the extreme position, then lowered down onto the sleeper cages. The span is lowered in stages by recharging the hydraulic jacks 4 by analogy with the lifting method described above. After installing the dismantled span structure on sleeper cages, the lower lifting beams located along and across the span and connections of collapsible frames are dismantled. The parts of the device separated in this way, located on the side of the bridge abutments, are moved along the rail tracks to the axis of the bridge. The dismantled superstructure is lifted from the sleeper cages, moved to the axis of the longitudinal sliding of the new superstructure, lowered onto the rolling tracks. The dismantled superstructure is longitudinally pushed at a low level onto the site from the assembly of a new superstructure and dismantled (SU No. 1649016 A1, E01D 22/00, 2001).
Lattice superstructures are usually dismantled by removal of spatial trusses by barges with subsequent cutting into individual elements, or dismantling element by element by floating cranes, or cranes moving along the superstructure. These methods are quite laborious and expensive, because do not remove the problem of element-by-element dismemberment of the span after transportation afloat, or a long period of work is required when element-by-element cutting of elements in place, which in many cases must first be strengthened and then cut. Such operations must be carried out with careful control of the stress state of the structure during the cutting of individual elements.
The objective of the proposed technical solution is to guarantee the dismantling of a spatial lattice span without a long-term occupation of the water area by floating facilities and temporary supports and to ensure a reduction in material and labor costs when performing these works due to the possibility of combining in time operations to disaggregate the span.
This is achieved by the fact that in the method of dismantling with three-dimensional blocks of the lattice span structure of the bridge with the height of the upper belt above the water level up to 30-35 m and with a span of more than 40 m, hydraulic jacks on temporary auxiliary supports under the lower nodes of the trusses, their temporary fixation, at least for the period of division, from vertical movement by wedging with steel sheets on the main or auxiliary supports, dismantling of the roadway in the zone of spatial blocks, division into three-dimensional blocks with a length not less than 20 m of the span by cutting or cutting individual elements of the truss while ensuring the regulation of internal forces in the truss by wedge and / or using hydraulic jacks installed on auxiliary supports within the limits of static loads acting in the truss elements that do not exceed the calculated ones, slinging, release removal from temporary fixation and dismantling of isolated blocks by a floating crane with a lifting capacity of at least 80 tons, moving them to pre-prepared receiving stocks for their disaggregation on the shore and dismantling of temporary auxiliary supports. In this case, the division of the truss can be carried out initially along the upper, then along the lower chords, starting from the upper plane of the truss. And the receiving stocks are placed on the shore, and the movement of the isolated blocks on them is carried out by a floating crane immediately after their dismantling, excluding transfer to a barge or pontoons. Alternatively, the receiving stocks are placed on the shore, and the movement of the isolated blocks on them is carried out by a floating crane after they are transferred to a barge or pontoons.
It is not every day that bridges are dismantled in Kiev, especially in their entirety. Of course, it was impossible to miss such a spectacle, especially since the dismantling was carried out by a rather rare railway crane. And to make it clearer how one big piece of iron is used to drag another big piece of iron, we shot a small time-lapse for you. Today's story will begin with it, and under the cut there is a detailed description of the process.
At the Darnitsa railway station, at the junction of the tracks to Petrovka and Vydubychi, there is an additional line that runs over the tracks that go towards the Darnitsa Bridge. The thread is needed to reduce the number of "cutting" routes, i.e. to reduce the need to cross oncoming flows in different directions.
1. An additional thread passes, or rather, passed through a completely ordinary single-span bridge.
2. He lived quietly in his usual life, until the second Darnitsky bridge was built and it turned out that there was not enough space under our bridge to lay an additional track. The fact is that both Darnitsa bridges have a total of 4 tracks, and closer to the Darnitsa station, there are actually only 3 of them, and there is nowhere to add one more yet.
In fact, this was not a surprise, and the restructuring of the neck of the Darnitsa station had been planned since the design of the new Darnitsa bridge. True, according to the original plans, the restructuring was supposed to be more comprehensive, but it is not known in what future this will happen, but for now it has been decided to limit itself to eliminating the main bottleneck and building the missing track to the Darnitsky bridge.
3. Therefore, it was decided to dismantle the hero of our report, which had a length of only 33 m, and instead build a new bridge 55 m long. Before dismantling the bridge, the rail grid and contact network were dismantled in advance. 
4. The old bridge turned out to be from the old school, when such structures were connected with rivets, not bolts, as they are now. However, the exact years of its construction are unknown to me. 
5. Work on the construction of a new one has been underway near the old bridge for more than a month. As soon as traffic across the bridge was closed, a cut was immediately made in the old embankment for the construction of piles under the abutment of the new bridge. 
6. Directly below the survey point, a new path to the Darnytsky Bridge will be skipped. 
The dismantling of bridges can be carried out in different ways. The specific method is chosen individually and depends on so many reasons. Since in our case the bridge is located over the intensively used tracks of the Nezhinsky + Yagotinsky directions, one of the main conditions for its dismantling is the minimum interruption in train traffic. Given the size and weight of the bridge (110 tons), it was decided to remove it completely and dismantle it on the ground in another place. For such an operation, a cantilever railway crane GEPC-130 with a lifting capacity of 130 tons was used. Only 6 such cranes were built in the USSR, one of them is located in Ukraine.
7. As the name implies, the crane is made in the form of two huge consoles that can swing up and down slightly. 
8. In the covered wagon there is a power plant that feeds the crane. The crane itself is not self-propelled and a shunting diesel locomotive is used to move it. 
9. The consoles are connected to the main (central) beam, which in turn is mounted on two eight-axle platforms. In the center is the control cabin. Along with the crane, there are four more platforms that resemble ordinary ones - they contain equipment for mounting the crane, and consoles are also transported, which are disconnected from the central beam in the transport position. 
10. A sling beam is suspended under each shoulder. A load is fixed on one of them, and a suspended counterweight weighing 43 tons is attached to the other. On top of the console sits another retractable counterweight weighing 63 tons (you can see it in this photo right above the slinging beam), which can move from one crane arm to another. As long as the crane is not loaded by the bridge, this counterweight compensates for the weight of the suspended counterweight located on the opposite side. After slinging the load, the retractable counterweight will be moved to the opposite arm of the crane. 
11. The crane seems to be preparing to eat the bridge :) 
12. Slinging cables: 
13. The slinging of the bridge can only begin after the traffic is completely blocked and the voltage is removed from the contact network under the bridge. A 3-hour window was allotted for dismantling that day. In the meantime, the window has not started and the movement continues, a railcar with a tower appears on one of the tracks and a partial dismantling of the contact network begins. 
14. The contact network is suspended directly from the bridge, so it must be dismantled before the start of the main work, and then quickly hung in a new place. 
15.
16.
17. Movement on adjacent tracks does not stop yet: 
18. You can’t easily remove the contact network from the attachment points, because. it is in a loaded state, therefore, before hanging, the ends of the cables are pulled together with a chain hoist: 
19.
20. The beginning of the window is getting closer: a second tower appears and another path is closed for movement. 
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22. Everything that can be removed is removed. The traffic light that was on the bridge has also been dismantled and must be installed in a new place within the allocated window. 
23. The guys who will dismantle the bridge, waiting for the window: 
24. Finally, all paths are blocked: the contacts are speeding up as much as possible so as not to interfere with the dismantling of the bridge, and at the top, vigorous slinging activity begins. 
25. The crane is driven inside the bridge truss: 
26. And they fix it with shoes until the bridge is raised to the required height so that it can be driven to the side with it. 
27. Chopped abutment and bridge: 
28.
29. The slinging beam is lowered down and slinging begins. 
30. And the cable is heavy, you won’t be able to stretch it alone. 
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33. In the meantime, a new cross-beam was brought up, on which a traffic light should be installed, and later a contact network will be suspended from it. 
34. The crossbar, in turn, still needs to be placed on pre-installed poles. 
35.
36. The traffic light is sent to a new location: 
37. But back to our bridge. 
38. The slinging is completed, the beam is raised up and the crane is now under load, preparing to tear the bridge from the abutments: 
39. Before lifting, the retractable counterweight of rattling and creaking moves to the opposite arm of the crane: 
40. Outsiders were driven out from under the bridge and from the bridge and everyone froze in anticipation of the start of the main action. 
41. Kontachi located on the best spectator seats: 
42. With a crack and grunt, as if in protest, the bridge begins to break away from the supports: 
43. An overbalance arose on one of the corners and the bridge leaned on its side so well: 
44.
45. A little more and you can take away:
46. Op! The crane with the bridge begins to slowly move forward: 
47.
48. Some kind of sur. 
49. …
50. I never thought that such a picture was even possible :) 
51. The bridge is being driven half a kilometer to the side, where a place for dismantling has been prepared along the straight section of the track. 
52. Before lowering under the bridge, it is also necessary to place rails along which it will later be moved sideways by jacks. 
53. Almost finish: 
54. The bridge has already been moved to the side to make way for technological transport, but, in my opinion, it has not yet begun to be dismantled. 
P.S. Thanks to NAS LLC and the administration of the South-Western Railway for organizing the shooting.
