Construction method of urban road-crossing steel truss bridge based on modular trailer group technology

Abstract

The invention discloses a construction method of a steel truss bridge crossing an urban road based on a module trailer group technology. The construction method comprises the following steps: constructing a lower structure of the bridge and mounting a support; according to a steel truss assembly site selection principle, a steel truss assembly area and a transfer path from the assembly area to a bridge position are comprehensively considered and selected; leveling treatment and hardening treatment are conducted on a steel truss transfer path site; designing and constructing a steel truss splicing platform; assembling the steel truss; the steel truss girder is transferred to a jacking area from the assembling area; jacking and loading the steel truss girder; lifting the steel truss girder and then carrying the steel truss girder to a bridge mounting position by a module trailer group; mounting a steel truss girder; the steel truss girder is installed on the pier column; and cast-in-place concrete slab pouring and bridge deck accessory structure construction are completed. The urban road crossing steel truss bridge construction method based on the module trailer group technology has the advantages that the overall construction period is shortened, the occupied area is saved, transportation is rapid and orderly, the influence of road traffic is reduced to the maximum extent, and safety and reliability are high.

Description

Technical Field

[0001] The invention relates to a steel truss bridge construction technology, in particular to a construction method of a steel truss bridge across a city road based on a module trailer group technology. Background Art

[0002] A steel truss bridge is a structure that hollows out a solid steel plate girder bridge according to specific rules. The structure is generally subjected to beam forces, primarily bending and shear forces. A steel truss bridge generally consists of a brake connection, a bridge deck, supports, and piers (abutments).

[0003] At present, the construction of steel truss bridges mainly adopts the bridge assembly method or the jacking method after the completion of the lower structure construction.

[0004] The site-assembly method requires the erection of a full-height scaffold after the substructure is completed, followed by on-site assembly. However, due to factors such as high scaffold material consumption, large construction space requirements, and long construction periods, the site-assembly method is not suitable for cross-city road bridge construction.

[0005] The jacking method requires the pre-installation of a complex set of auxiliary construction facilities, including temporary support, guided jacking, and bridge beam drop. The trusses must be assembled at a defined location, and the bridge must be moved along pre-installed slideways to the piers before the beams are dropped to complete the installation. The jacking method has a complex construction process and places high demands on the surrounding conditions of the bridge site. It poses significant potential quality and safety risks and creates uncontrollable factors affecting the construction schedule. Furthermore, construction near roads requires long-term traffic control, which can easily lead to traffic congestion and traffic safety hazards.

[0006] Therefore, it is very necessary to seek a construction method that has little impact on the construction period, requires low construction site space, and can effectively reduce safety hazards for the construction of cross-city road bridges. Summary of the Invention

[0007] The present invention aims to avoid the shortcomings of the above-mentioned existing technologies and provide a construction method for a steel truss bridge across an urban road based on modular trailer group technology, so as to shorten the construction period, reduce the space requirements for the construction site and improve construction safety.

[0008] The present invention adopts the following technical solutions to solve the technical problems.

[0009] The present invention provides a construction method for a steel truss bridge across an urban road based on a modular trailer group technology, comprising the following steps:

[0010] Step 1: Construction of the bridge substructure and installation of supports; the substructure includes pile foundations, caps and piers;

[0011] Step 2: Site selection for steel truss assembly and transfer routes: Based on the steel truss assembly site selection principles, comprehensively consider and select the steel truss assembly area and the transfer route from the assembly area to the bridge location;

[0012] Step 3: Treatment of the site for the transfer path of the steel truss 1; leveling and hardening the road for the transfer path of the steel truss 1;

[0013] Step 4: Design and construction of the steel truss 1 assembly platform; the steel truss assembly platform includes a base 3 and columns 2; the columns 2 are fixed on the base 3;

[0014] Step 5: Steel truss assembly;

[0015] Step 6: Transfer the steel truss 1 from the assembly area to the jacking area;

[0016] Step 7: Lifting and loading of steel trusses: After lifting, the steel trusses are transported to the bridge installation location by the modular trailer group;

[0017] Step 8: Installation of steel trusses: Install the steel trusses on the piers;

[0018] Step 9: Complete the pouring of cast-in-place concrete slabs and the construction of bridge deck auxiliary structures.

[0019] The construction method of a steel truss bridge across a city road based on modular trailer group technology of the present invention is also characterized in that:

[0020] During specific implementation, in step 1, a building brick wall is selected as a permanent formwork to pour the foundation concrete.

[0021] In the specific implementation, in step 4, the column 2 is a steel structure column with a length, width and height of 1.2m×1.2m×1.5m.

[0022] During specific implementation, in step 4, the foundation base 3 is a cast-in-place reinforced concrete foundation base, and the length, width and height dimensions of the foundation base are 2.5m×2.5m×1m.

[0023] During specific implementation, in step 6, a modular trailer group is used to transport the steel trusses from the assembly area to the lifting area; and a heavy modular jack is used to lift the steel trusses.

[0024] In a specific implementation, the heavy-duty modular jack includes a power pack, a lifting base, a plug-in module box receiving box, a top bearing box, a lifting module box and a bottom stabilizing box.

[0025] In a specific implementation, the modular trailer group is 2 groups of 12-axle modular trailer groups.

[0026] During specific implementation, in step 7, the modular trailer group is 4 groups of 12-axle modular trailer groups.

[0027] During specific implementation, in step 8, during the installation process of the steel truss, an operation schedule is prepared in advance, and each step is performed strictly in accordance with the operation schedule.

[0028] In specific implementation, in step 8, during the installation of the steel trusses, the steel trusses are unloaded in a 20% incremental step-by-step manner when they are dropped.

[0029] Compared with the existing technology, the beneficial effects of the present invention are embodied in:

[0030] The present invention discloses a construction method for a steel truss bridge across an urban road based on modular trailer group technology, comprising: construction of a bridge substructure and installation of supports; selection of a steel truss assembly area and a transfer path from the assembly area to the bridge location based on the steel truss assembly site selection principle; leveling and hardening of the steel truss transfer path site; design and construction of a steel truss assembly platform; assembly of the steel trusses; transfer of the steel trusses from the assembly area to the jacking area; jacking and loading of the steel trusses; transporting the lifted steel trusses to the bridge installation location by means of a modular trailer group; installation of the steel trusses; installation of the steel trusses on piers; and completion of pouring of cast-in-place concrete slabs and construction of the bridge deck accessory structure.

[0031] The method for constructing a steel truss bridge across a city road based on modular trailer group technology has the advantages of shortening the overall construction period, saving floor space, rapid and orderly transportation, minimizing the impact of road traffic, and high safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a schematic diagram of a steel truss assembly platform for a steel truss bridge across a city road based on modular trailer group technology.

[0033] Figure 2 This is a distribution diagram of temporary supports for a steel truss assembly platform of a steel truss bridge across a city road based on modular trailer group technology according to the present invention.

[0034] Figure 3 The diagram is a schematic diagram of the assembled steel truss beams of a steel truss bridge across a city road based on the modular trailer group technology according to the present invention.

[0035] Figure 4 This is a schematic diagram of the operation of a modular trailer group in the steel truss assembly area of a steel truss bridge across urban roads based on the modular trailer group technology of the present invention.

[0036] Figure 5 This is a schematic diagram of the steel truss beam lifting area of a steel truss bridge across a city road based on the modular trailer group technology of the present invention.

[0037] Figure 6This is a schematic diagram of the completion of the jacking of the steel truss beams of a steel truss bridge across a city road based on the modular trailer group technology of the present invention.

[0038] Figure 7 This is a schematic diagram of loading steel trusses for a steel truss bridge across a city road based on modular trailer group technology according to the present invention.

[0039] Figure 8 The present invention is a schematic diagram of the steel truss beam transportation of a steel truss bridge across a city road based on the modular trailer group technology.

[0040] Figure 9 This is a schematic elevation diagram of the installation of steel trusses for a steel truss bridge across a city road based on modular trailer group technology according to the present invention.

[0041] Figure 10 This is a top view of the installation of steel trusses of a steel truss bridge across a city road based on the modular trailer group technology of the present invention.

[0042] The present invention will be further described below through specific implementation methods in conjunction with the accompanying drawings. DETAILED DESCRIPTION

[0043] See also Figures 1 to 10 The present invention provides a construction method for a steel truss bridge across a city road based on a modular trailer group technology, comprising the following steps:

[0044] Step 1: Construction of the bridge substructure and installation of supports; the substructure includes pile foundations, caps and piers;

[0045] During this step, the substructure, including pile foundations, caps, and piers, was constructed and the bearings installed according to the design drawings. During construction, given the limited space available for the cap within the central median of the road, a brick wall was constructed as a permanent formwork for pouring the cap concrete.

[0046] During substructure construction, adjacent lanes will be temporarily closed during low-traffic times to expand construction space. Specifically, one adjacent lane can be closed periodically during construction, depending on construction needs. Traffic volume decreases significantly at night, especially during the early morning hours, allowing substructure construction to be concentrated at night and traffic to resume during the day. When closing the adjacent lanes, a truck carrying a buffer will be deployed 300 meters in front of the construction site. Warning cones will be placed starting from the truck's location, with warning lights installed every 50 meters.

[0047] Step 2: Site selection for steel truss assembly and transfer routes: Based on the steel truss assembly site selection principles, comprehensively consider and select the steel truss assembly area and the transfer route from the assembly area to the bridge location;

[0048] Based on sufficient research, the best steel truss assembly site is selected and the transportation route of the steel trusses is planned.

[0049] The aforementioned steel truss assembly site selection principles include: thoroughly investigating the geological conditions and architectural environment surrounding the steel truss assembly site and within the transfer route area, comprehensively considering availability and affordability when selecting sites, and avoiding sites or routes with nearby oil and gas pipelines, high-voltage lines, and other third-party property, as well as sites requiring extensive renovation to meet requirements. The site selection process is based on the research results and is based on the nearest location. When selecting a site, avoid areas and routes with complex surrounding architectural environments and dense underground facilities. This is to avoid damage to existing buildings and facilities within the construction area and to minimize the need for renovations to existing sites and the required protective measures, thus reducing costs.

[0050] Step 3: Treatment of the site for the transfer path of the steel truss 1; leveling and hardening the road for the transfer path of the steel truss 1;

[0051] To ensure the stability and safety of the steel trusses during transportation from the assembly area to the bridge site, the assembly area work site and transfer path must be leveled and hardened. If the steel truss transfer path crosses an existing highway, partial median guardrails can be removed with permission from the traffic control department, and the central median area along the transfer path must be leveled and hardened. During traffic hours, easily removable concrete barriers will temporarily replace the removed median guardrails. Once the road is closed to traffic, the concrete barriers will be removed to allow tow trucks to pass until construction is complete and the road surface is restored.

[0052] Use a level to measure the elevation of the steel truss assembly area and the bridge installation site. The elevation should not differ significantly from the road surface on which the bridge sits. Use a grader or bulldozer to level the site. After the assembly area is leveled and hardened, use a vibratory roller for compaction.

[0053] If it is necessary to fill the site to raise the elevation, it must be leveled and compacted layer by layer, with each layer of fill not exceeding 200mm. Use a vibratory roller to roll the site at least four times. Once the required elevation is reached and fully compacted, a 10cm thick water-stabilized fill material is placed on top and compacted again. After the compaction is complete, a flat plate load test is conducted on the site. A foundation bearing capacity report is obtained for the assembly and transportation requirements of the full steel truss to ensure that the foundation bearing capacity meets the requirements of each stage of steel truss assembly and transportation.

[0054] Step 4: Design and construction of the steel truss 1 assembly platform; the steel truss assembly platform includes a base 3 and columns 2; the columns 2 are fixed on the base 3;

[0055] The assembly platform is shown as follows Figure 1 and Figure 2When designing the assembly platform height, the safety and economy of the entire construction process must be considered simultaneously. The elevation of the support top surface should be minimized while ensuring that the space required for the modular trailer assembly is met. This not only ensures the stability of the support system under extreme weather conditions, but also reduces construction difficulty and saves on additional expenses such as construction formwork, auxiliary scaffolding, and column stability reinforcement materials.

[0056] When assembling steel trusses on site, the assembly platform ensures that the reserved space at the bottom of the steel trusses meets the minimum requirements for the passage of the modular trailer group and is not greater than the maximum height that the trailer flatbed can reach due to the integrated hydraulic system of the modular vehicle. The setting of the platform support points fully considers the stress distribution of the steel truss bridge during the assembly process to ensure that the deformation of the structure is within the allowable range.

[0057] like Figure 1 As shown, a set of independent temporary piers are used as the assembly platform. The piers are composed of steel columns. The columns 2 of the steel truss assembly platform are connected to the foundation base 3 with pre-buried high-strength bolts. The upper part is adjusted to the level by high-strength pads, and the steel truss chords are contact supports.

[0058] Before the construction of the concrete foundation base begins, the coordinates must be set out according to the design drawings. The construction of the steel truss assembly platform columns must be carried out according to the design elevation. The existing ground must be excavated and the base must be fully compacted. After the foundation base construction and steel structure column installation are completed, the base must be backfilled with high-compactness backfill materials to the initial elevation, leveled and compacted. Figure 2 shown.

[0059] Step 5: Steel truss assembly;

[0060] like Figure 3 When assembling the steel truss 1, assemble it in the predetermined order of the lower chord, crossbeam, longitudinal beam, web member, and upper chord. Complete the surface treatment and spray painting of the steel truss and the quality inspection before the bridge installation. Remove the scaffolding and clean the site. Prepare the modular vehicle for transporting the steel truss.

[0061] During the on-site assembly process, the steel trusses are rationally divided into multiple structural units, which are independently processed and welded in the workshop. Once the on-site assembly platform and other auxiliary equipment and facilities are ready, the completed structural units are transported to the site using a flatbed trailer for further assembly and welding according to the designed sequence.

[0062] During the on-site assembly construction of the steel trusses, after the steel trusses are assembled, the concrete beam and slab bottom surface pavement layer and the beam and slab reinforcement are further laid in place. After the steel trusses are finally erected, concrete is poured in situ to complete the construction.

[0063] In this invention, the steel trusses are assembled using a fully welded solution. Compared to riveting, welded structures offer simpler design, a wider range of proven welding processes, and faster construction. The welding process is not limited by plate thickness, making welding easier when thicker plates are used in heavy-duty structures. Welded structures also offer excellent watertightness and corrosion resistance, extending their service life in hot and humid climates or coastal areas.

[0064] During the welding process, flux-cored gas shielded welding is used to divide the steel trusses into several easily transportable structural units, which are then individually processed and assembled. Each unit is welded in the workshop, strictly following a specific welding sequence and quality management process. Each weld undergoes all non-destructive testing (NDT) procedures, including visual inspection, ultrasonic testing, radiographic testing, magnetic particle testing, liquid penetrant testing, and phased array ultrasonic testing.

[0065] After the on-site assembly platform and various equipment and facilities are ready, the components processed in the workshop are transported to the assembly site using a flatbed trailer and assembled according to the following construction procedures:

[0066] Step 51: Set up the welding platform scaffolding and arrange fire retardant oil in the welding construction area;

[0067] Step 52: Fix the left lower chord to temporary brackets equipped with high-strength pads and adjust them precisely into position using measuring instruments;

[0068] Step 53: Fix the right lower chord to temporary brackets equipped with high-strength pads and adjust them precisely into position using measuring instruments;

[0069] Step 54: Install the first composite component; the first composite component includes the end crossbars, crossbeams, and longitudinal beams, and is butt-welded to the lower chord.

[0070] Step 55: Install the second assembly component; the second assembly component includes end cross bars and beams, longitudinal beams, and is aligned with the lower chord; further connect the longitudinal beams and the bottom beam assembly component by welding; Figure 3 shown.

[0071] Step 56: Complete the assembly and welding of the lower chord and the transverse and longitudinal beams according to the above steps 54 and 55;

[0072] Step 57: Install the right vertical unit member; the right vertical unit member includes vertical bars, diagonal bars and upper chord bars, and they are butt-welded to the lower chord bars according to the design;

[0073] Step 58: Install the right end diagonal rod and complete the butt welding with the right lower chord rod and the right upper chord rod respectively;

[0074] Step 59: Install the left vertical unit component; the installation process of the left vertical unit component is the same as the installation process of the right vertical unit component in steps 57 and 58 above;

[0075] Step 510: Install the concrete beam and slab bottom surface pavement and pre-tie the steel bars;

[0076] Step 511: Complete the surface treatment and spraying of the steel trusses and the quality inspection before the bridge installation;

[0077] Step 512: Remove the scaffolding, clean up the site, and prepare the modular vehicle to transport the steel trusses.

[0078] Step 6: Transfer the steel truss 1 from the assembly area to the jacking area;

[0079] Use two sets of 12-axle modular trailers to transport the steel trusses from the assembly area to the jacking area. Each trailer is made up of two 6-axle modular vehicles connected longitudinally. Each trailer is equipped with a power unit, or each modular trailer is equipped with an independent power unit. Use modular trailers to carry the steel trusses from the assembly area to the jacking area, such as Figure 4 shown.

[0080] Before the steel trusses are carried away from the assembly platform by the module trailer group, the 48-hour weather forecast must be checked and whether to proceed to the next step must be determined based on the weather conditions.

[0081] After the steel trusses are assembled, four heavy-duty modular jacks 6 are used to lift the assembled steel trusses to an appropriate height to meet the installation requirements of the bridge location.

[0082] The heavy-duty modular jack includes the following components: a power pack, a lifting base (4030×2200×1770mm), a plug-in module box receiving box (2500×1200×532mm), a top load-bearing box (2075×2000×550mm), a lifting module box (2075×2000×550), and a bottom stabilizing box (2184×2052×405mm). After the module box in the module box receiving box is lifted to its designed stroke using the jack in the lifting base, the lateral sliding support in the base slides out to take over the jack's load. After the jack is reset, the module box receives the lifting module box again, and the base jack operates again. This cycle gradually raises the height of the top load-bearing box, thereby raising the height of the object being carried.

[0083] Before commencing transfer and jacking work, check and confirm that all preparatory work is complete. Ensure that on-site traffic is unobstructed; the traffic roads and jacking areas are fully leveled and hardened, and obtain an approved foundation bearing capacity test report. Through stress distribution calculations, determine and mark the appropriate number and location of temporary support points on the bottom of the steel trusses. The number and location ensure that the deformation of the steel trusses during transfer is within the allowable range of regulations. Mark the center control line and direction guide lines on the trusses. Complete on-site safety and technical briefings.

[0084] In specific implementation, the transfer process includes the following steps:

[0085] Step 61: In the jacking area that has been leveled and hardened, use measuring instruments to stake out the steel truss positions and control lines;

[0086] Step 62: Place load distributing pads at the positions corresponding to the four supports of the steel truss. The load distributing pads are used to place modular jacks.

[0087] Step 63: Use a mobile crane to lift the jacking base of the heavy-duty modular jack onto the load-distributing pads.

[0088] Step 64: Adjust the position and elevation of the jacking base;

[0089] The design center of the jacking base corresponds to the position of the steel truss support. By adding high-strength spacers between the load-distributing pad and the jacking base to adjust the elevation, the height difference between the top surfaces of the four bases is controlled within 10mm.

[0090] Step 65: Connect the control cables and hydraulic hoses between the control room, power box and heavy modular jacks, and finally connect to the central control computer;

[0091] Step 66: Test the installed electrical system, power system, braking system, steering system and other systems to ensure that the systems are operating normally;

[0092] Step 67: Prepare enough spacers according to the designed height and place them neatly next to the four jacking bases of the jacking module box to ensure that the jacking work forms a streamlined workflow and can be carried out in an orderly manner;

[0093] Step 68: According to the steel truss installation plan, complete the assembly of two sets of 12-axle modular trailer groups at the designated location on site in advance; during implementation, each trailer group is composed of 6-axle unit modular trailer groups connected longitudinally and equipped with a power box; on the top surface of the assembled trailer, steel beams are installed at the corresponding distribution positions of the steel truss carrying support points to support the steel trusses; after the modular trailer groups are assembled, the synchronization and control performance of multiple modular trailer groups are tested.

[0094] Step 69: The modular trailer is assembled and integrated by professionals. Before the trailer is officially put into use, the system must be fully tested and troubleshooted according to the safety and technical briefing documents to ensure that the hydraulic oil pipes and electrical systems are connected correctly and that the trailer system operates stably and smoothly.

[0095] Step 610: Drive the two debugged module trailer groups to the predetermined position between the bottom of the steel truss and the temporary assembly pier 5;

[0096] Step 611: Adjust the position and direction of the trailer so that the pre-arranged steel beam on the trailer is aligned with the carrying support point marked on the bottom of the steel truss, and place plywood on the upper surface of the supporting steel beam as a buffer structure;

[0097] Step 612: After the trailer and the support points are aligned, slowly raise the trailer platform until the supporting points on the bottom surface of the steel truss bridge contact the vehicle-mounted steel beam support. Then, pause the raising, check again to confirm that the alignment is correct, and continue raising the trailer platform to separate the steel truss bridge from the temporary assembly pier 5.

[0098] Step 613: After rechecking that the hydraulic oil pipes and the power system are connected normally, continue to lift the trailer flatbed to the predetermined height and secure the steel truss bridge to the trailer with a special rope.

[0099] Step 614: Check the 48-hour weather forecast. If all conditions are met, start transporting to the jacking area and proceed to the next step. If the weather is bad, the trailer can continue to transport the steel trusses to the jacking area, but they must remain fixed on the trailer until no adverse weather conditions are expected.

[0100] Step 615: The trailer carries the steel truss bridge to the jacking area and drives along the centerline between the four jacking bases. The trailer adjusts its direction and position to align the center of the modular jack's load-bearing module box with the center of the bridge support position marked on the bottom of the steel truss.

[0101] Step 616: After confirming that it is in place, loosen the ropes that secure the steel trusses and slowly lower the trailer platform height through the modular trailer group integrated hydraulic system until the steel trusses are separated from the vehicle support and the load is completely transferred to the modular jacks. The trailer is then withdrawn and preparations for the jacking operation are started.

[0102] Step 7: Lifting and loading of steel trusses: After lifting, the steel trusses are transported to the bridge installation location by the modular trailer group;

[0103] like Figure 5 、 Figure 6 and Figure 7, using four heavy-duty modular jacks to lift the steel trusses to the designed installation elevation. After the lifting is completed, the modified modular trailers are used again to carry the steel trusses and transport them to the bridge installation location along the established route. The specific steps are as follows:

[0104] Step 71: After confirming that the module trailer assembly and steel trusses are in place, start powering on the jacking system;

[0105] Step 72: Before the jacking operation officially begins, perform functional tests such as hydraulic and brake tests on the system according to the risk assessment report, emergency plan, and other safety and technical documents to ensure that parameters such as load and vehicle body inclination are correct;

[0106] Step 73: Use a crane to place the top bearing boxes of the four modular jacks into the receiving box and install them in place. Place a cushioning rubber pad on top of the top bearing box. At this point, the clearance between the top surface of the modular jack and the steel truss support position should be within 500mm.

[0107] Step 74: Once ready, start the modular jack and slowly lift the top load box until it contacts the steel truss. The load is gradually transferred from the trailer to the modular jack.

[0108] Step 75: During the load transfer process, the settlement of the base at each lifting point, the deformation of the contact interface of the top bearing box, and the loading of each lifting base are continuously monitored, and the data are periodically read and recorded at 20% load increments.

[0109] Step 76: When the load transfer reaches 80% of the total design load, suspend the lifting and check whether each modular jack is operating normally;

[0110] Step 77: When the load transfer reaches 100% of the total load weight, suspend the lifting and check whether the module boxes of each modular jack are in full contact, that is, check whether the lifting module boxes of two adjacent jacks are in contact with each other; the heavy-duty modular jack includes a power pack, a lifting base, a plug-in module box receiving box, a top bearing box, a lifting module box, and a bottom stabilizing box;

[0111] Step 78: Check and compare the deviation between the actual load and the expected load. The deviation should be kept within 5%. If the deviation exceeds the expected value, the lifting should be stopped and further operation can be started after the cause is determined and the corresponding emergency plan is formulated.

[0112] Step 79: After the steel truss is completely separated from the module trailer, confirm again that the jacking system is operating normally, the top bearing box is in good contact with the steel truss, and the load is as expected, then slowly drive the trailer away from the jacking area;

[0113] Step 710: After the modular jack is lifted to a predetermined height, the lateral sliding support on the lifting base is used to bear the load instead of the jack, and the jack is restored to its original position;

[0114] Step 711: Use a crane or forklift to place a new lifting module box into the plug-in module box receiving box and repeat the above step 710; gradually raise the height of the steel truss. Before reaching the required height, manually tighten the bolts between all the newly installed lifting module boxes;

[0115] Step 712: After the new lifting module box reaches the final lifting height, it can be determined whether to install a bottom stabilization box based on the needs. If the current status needs to be maintained for a long time due to an emergency or sudden severe weather, a bottom stabilization box must be installed to enhance stability.

[0116] Step 713: The modular trailers for installing the steel trusses on the bridge site consist of four 12-axle modular trailers arranged side by side horizontally. During the jacking operation, the beam support brackets 7, designed according to the load-bearing requirements, are installed on the trailer flatbeds for reinforcement, forming the final transfer and installation system. The bracket top surface elevation is adjusted to meet the required height for the bridge installation.

[0117] Step 714: The four module trailers with the vehicle-mounted brackets fixed and adjusted are driven back to the bottom of the raised steel truss. The positions are adjusted so that the support points of the vehicle-mounted brackets are aligned with the temporary support points of the steel truss.

[0118] Step 715: Lift the trailer flatbed via the integrated hydraulic device inside the modular trailer assembly. Continue to lift it about 100mm after it contacts the steel truss support point. Use special ropes to reinforce the steel truss and trailer, and transport it to the bridge installation location along the established route.

[0119] Step 8: Installation of steel trusses: Install the steel trusses on the piers;

[0120] The module trailer group carries the steel truss and moves to the installation location. Figure 8 At this point, the steel truss is completely above the pier column. The support center is adjusted to align with the support center of the cast-in-place pier column. The steel truss is lowered through the modular trailer group integrated hydraulic system. After checking and confirming that the bridge position deviation is within the allowable range, the lock between the steel truss and the trailer is released, and the final beam is lowered using a staged unloading method. Figure 9 、 Figure 10 shown.

[0121] The steel truss beam lowering process is carried out in a 20% incremental graded unloading manner. Unloading is suspended after the trailer unloading reaches 80%, and a final inspection is carried out to confirm that the bridge position is within the allowable deviation error range. Then all the trailer load is further released, and the vehicle-mounted bracket is separated from the bottom of the steel truss beam.

[0122] The specific process of installing the steel truss includes the following steps:

[0123] Step 81: Apply for road closure permission from the traffic control department. To ensure that traffic can be restored on time after the road closure, develop a reasonable operation schedule based on the time requirements of each stage and strictly follow the established plan;

[0124] Step 82: Check the status of various emergency response plans and develop emergency response plans or prepare backup equipment for tire damage, hydraulic or electrical failures, power system unit failures, etc.

[0125] Step 83: Before the modular trailer transports the steel truss bridge to the installation site, conduct a final inspection of the reinforcement ropes, brackets, and the modular trailer itself.

[0126] Step 84: Before traffic is interrupted at the bridge installation location, the modular trailer group carries the steel trusses out of the jacking area and stands by near the installation location until the road is taken over;

[0127] Step 85: After the road is taken over, the person in charge of the construction road will immediately conduct an inspection along the transfer route to remove stones and other debris that may affect the transportation process. After the inspection is completed, the module trailer team will be notified to start entering the site;

[0128] Step 86: The start command of the modular trailer group is issued by the responsible person. After the start command is issued, the trailer group will be driven according to the established route and design speed. During the driving process, the oil pressure status of each modular trailer group will be continuously monitored. If the oil pressure difference between each group exceeds the allowable range, the trailer movement will be suspended. After the cause is identified and an adjustment plan is formulated, the trailer will be restarted.

[0129] Step 87: The modular trailer group carries the steel truss along the established route and stops about 1.5m away from the pier. Then, first check to confirm whether the gap between the bottom of the steel truss and the support is sufficient, and adjust the trailer height accordingly to the appropriate gap; then check to confirm and adjust the alignment of the steel truss bridge to ensure that there is no conflict with adjacent structures. Figure 8 shown.

[0130] Step 88: After the inspection and confirmation are completed, the module trailer group continues to move forward, and the observers continue to monitor the height and orientation of the steel trusses and use wireless communication equipment to maintain communication with the module trailer group commander to make timely adjustments;

[0131] Step 89: The module trailer group moves until the steel truss is completely above the pier column, and the center of the designed support is aligned with the center of the support on the cast-in-place pier column, as shown in the figure. Figure 9The steel truss is lowered further using the modular trailer's integrated hydraulic system, reducing the gap between the pier support and the bottom of the truss without contacting it. After confirming that the bridge's position deviation is within the allowable range, the ropes securing the steel truss and the trailer are released, preparing for the final lowering of the truss.

[0132] Step 810: During the beam lowering process, the load is transferred to the pier column support. The module trailer group is unloaded in a stepwise manner with 20% increments. When the module trailer group has unloaded 80%, the unloading is suspended. Finally, a check is conducted to confirm that the bridge position is within the allowable deviation error range. Then, all loads on the module trailer group are further released, and the vehicle-mounted bracket is separated from the bottom of the steel truss.

[0133] Step 811: The module trailer group leaves the site and traffic is restored.

[0134] Step 9: Complete the pouring of cast-in-place concrete slabs and the construction of bridge deck auxiliary structures.

[0135] Considering the limited construction space across an existing road, the high safety risks, and the impact on traffic, the bottom formwork steel plate and beam slab reinforcement for the cast-in-place concrete bridge deck were installed before the girder erection. After the steel trusses were erected, the girder bottoms were cleaned and the bridge deck concrete was poured. After the curing period, the construction of other bridge deck ancillary structures was completed.

[0136] This invention uses modular trailer technology to transport off-site assembled steel trusses to the bridge site for installation. This method transforms the linear construction process between the steel truss bridge substructure and the steel trusses into parallel construction.

[0137] During specific implementation, in step 1, a building brick wall is selected as a permanent formwork to pour the foundation concrete.

[0138] When constructing a foundation within the central median of a road, the limited construction site and available excavation space make conventional formwork and concrete pouring impossible. This invention uses a brick wall as a permanent formwork for concrete pouring, with the gaps behind the wall backfilled and compacted layer by layer using the self-compacting properties of quicksand upon contact with water.

[0139] In a limited space, a brick wall is used as a permanent formwork to cast the pedestal concrete. The construction process is as follows: (1) foundation treatment; (2) pouring concrete cushion layer; (3) constructing a surrounding brick wall with the pedestal size as the inner boundary and the cushion layer as the foundation; (4) for every 0.5m increase in the height of the brick wall, fill the gap behind the wall with quicksand and sprinkle water to make it dense manually; (5) construct the brick wall to the height of the pedestal surface; (6) apply cement mortar to the inside of the wall; (7) clean the foundation pit inside the brick wall; (8) construct waterproof membrane on the concrete cushion layer and mortar surface; (9) pour 50mm mortar protection board on the base; (10) tie the pedestal steel bar and the embedded steel bar of the pier column; (11) pour concrete.

[0140] In the specific implementation, in step 4, the column 2 is a steel structure column with a length, width and height of 1.2m×1.2m×1.5m.

[0141] During specific implementation, in step 4, the foundation base (3) is a cast-in-place reinforced concrete foundation base, and the length, width and height dimensions of the foundation base are 2.5m×2.5m×1m.

[0142] During specific implementation, in step 6, a modular trailer group is used to transport the steel trusses from the assembly area to the lifting area; and a heavy modular jack is used to lift the steel trusses.

[0143] In a specific implementation, the heavy-duty modular jack includes a power pack, a lifting base, a plug-in module box receiving box, a top bearing box, a lifting module box and a bottom stabilizing box.

[0144] In a specific implementation, the modular trailer group is 2 groups of 12-axle modular trailer groups.

[0145] During specific implementation, in step 7, the modular trailer group is 4 groups of 12-axle modular trailer groups.

[0146] During specific implementation, in step 8, during the installation process of the steel truss, an operation schedule is prepared in advance, and each step is performed strictly in accordance with the operation schedule.

[0147] The operation process timetable for each link includes: 0.5 hours of road closure and obstacle clearing, 1 hour for the modular trailer group to run from off-site to the bridge position, 1 hour for azimuth and elevation adjustment, 1 hour for beam dropping and trailer unloading, 0.5 hours for trailer withdrawal, 0.5 hours for road facility reconstruction, and 0.5 hours for removing road closure signs and resuming traffic, for a total of 5 hours.

[0148] In specific implementation, in step 8, during the installation of the steel trusses, the steel trusses are unloaded in a 20% incremental step-by-step manner when they are dropped.

[0149] The method for constructing a steel truss bridge across a city road based on modular trailer group technology of the present invention has the following characteristics.

[0150] 1. The construction method of this invention allows for the completion of bridge substructure construction at night, when traffic is light, by closing a small number of lanes to expand construction space. The superstructure steel trusses are then assembled off-site near the bridge site. Finally, by completely closing the lanes in a very short time, the steel trusses are transported to the bridge site using modular trailers for complete drop-off. Substructure construction can be carried out simultaneously with the production and assembly of the steel truss components. This shifts the linear construction relationship between the steel truss bridge substructure and the steel trusses to parallel construction, significantly shortening the construction period for the truss sections and the overall duration of the bridge.

[0151] 2. The construction method of the present invention optimizes the welding and assembly construction process by rationally dividing the steel trusses into multiple structural units that are easy to store and transport. The welding production of each structural unit is completed in the production workshop, and after the site is ready, it is transported to the assembly site for further assembly using a flatbed trailer. This largely avoids excessive accumulation of materials and equipment on site and saves floor space.

[0152] 3. The construction method of the present invention conducts long-term monitoring and statistical analysis of traffic flow conditions on the road where the bridge is located at different time periods every day before construction, formulates temporary traffic diversion and organization plans for different stages including substructure construction and steel truss beam transfer and dropping construction, and obtains approval from the road management department in advance before implementation, striving to carry out bridge construction safely and orderly while minimizing the impact on road traffic.

[0153] 4. The construction method of the present invention minimizes or avoids cross-road construction in each construction link. For example, the substructure construction is carried out during the period with the least traffic pressure based on traffic flow analysis. The concrete bridge deck steel mesh and formwork are laid in place before the beams are erected, which reduces the time and number of traffic control requirements of the cross-road work team and effectively reduces the safety risks during construction.

[0154] 5. The construction method of the present invention, through the rational use of modular trailers and heavy modular jacks, realizes the separation of steel trusses from the assembly platform, and then lifts them to a high position, and finally loads them onto trailer-mounted brackets and transports them to the bridge site for installation. Two groups of 12-axis modular trailers and four groups of heavy modular jacks are used in the separation and height lifting stages, and four groups of 12-axis modular trailers and container-modified vehicle-mounted brackets are used in the transportation and installation stages. The process is fast and orderly, and while making full use of on-site mechanical equipment resources, it avoids the transportation difficulties, time-consuming assembly, and large land requirements of using oversized lifting equipment. It is economical, safe, and reliable.

[0155] The present invention's method for constructing a steel truss bridge across urban roads, based on modular trailer technology, relies on modular trailer technology to transport off-site assembled steel trusses to the bridge site and complete installation and construction. In terms of construction procedures, the linear construction between the steel truss bridge substructure and the steel trusses is converted into parallel construction; in terms of construction technology and method selection, the difficulty of assembling the steel trusses is minimized, assembly efficiency is improved, and the speed and safety of transporting the steel trusses are increased; in terms of construction site utilization, the land occupation is minimized, and existing roads are fully utilized as installation platforms. The above optimization can effectively shorten the overall construction period of the bridge and reduce the cost of temporary facilities. At the same time, because the traffic control time requirement is short and the number of times is small, the time of traffic impact is avoided to the greatest extent, reducing safety risks during construction.

[0156] In summary, the cross-city road steel truss bridge construction method based on modular trailer group technology of the present invention has the advantages of shortening the overall construction period, saving floor space, fast and orderly transportation, minimizing the impact of road traffic, and high safety and reliability.

[0157] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0158] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A construction method for a steel truss bridge across an urban road based on modular trailer group technology, characterized in that: The steps include: Step 1: Construction of the bridge substructure and installation of supports; the substructure includes pile foundations, caps and piers; Step 2: Site selection for steel truss assembly and transfer routes: Based on the steel truss assembly site selection principles, comprehensively consider and select the steel truss assembly area and the transfer route from the assembly area to the bridge location; Step 3: Processing of the transport path of the steel truss (1); leveling and hardening of the road of the transport path of the steel truss (1); Step 4: Design and construction of a steel truss (1) assembly platform; the steel truss assembly platform includes a base (3) and columns (2); the columns (2) are fixed on the base (3); Step 5: Steel truss assembly; Step 6: Transfer the steel truss (1) from the assembly area to the jacking area; Step 7: Lifting and loading of steel trusses: After lifting, the steel trusses are transported to the bridge installation location by the modular trailer group; Step 8: Installation of steel trusses: Install the steel trusses on the piers; Step 9: Complete the pouring of cast-in-place concrete slabs and the construction of bridge deck auxiliary structures.

2. The construction method of a steel truss bridge across a city road based on modular trailer technology according to claim 1 is characterized in that: In step 1, a building brick wall is selected as a permanent formwork to pour the foundation concrete.

3. The construction method of a steel truss bridge across a city road based on modular trailer technology according to claim 1 is characterized in that: In step 4, the column (2) is a steel structure column with dimensions of 1.2m×1.2m×1.5m in length, width and height.

4. The construction method of a steel truss bridge across a city road based on modular trailer technology according to claim 1 is characterized in that: In step 4, the foundation base (3) is a cast-in-place reinforced concrete foundation base, and the length, width and height dimensions of the foundation base are 2.5m×2.5m×1m.

5. The construction method of a steel truss bridge across a city road based on modular trailer technology according to claim 1 is characterized in that: In step 6, a modular trailer group is used to transport the steel trusses from the assembly area to the lifting area; and a heavy modular jack is used to lift the steel trusses.

6. The method for constructing a steel truss bridge across a city road based on modular trailer technology according to claim 5, wherein: The heavy-duty modular jack includes a power pack, a lifting base, a plug-in module box receiving box, a top bearing box, a lifting module box and a bottom stabilizing box.

7. The method for constructing a steel truss bridge across a city road based on modular trailer technology according to claim 5, wherein: The modular trailer group is 2 groups of 12-axle modular trailer groups.

8. The method for constructing a steel truss bridge across a city road based on modular trailer technology according to claim 1, wherein: In step 7, the modular trailer group is 4 groups of 12-axle modular trailer groups.

9. The method for constructing a steel truss bridge across a city road based on modular trailer technology according to claim 1, wherein: In step 8, during the installation of the steel trusses, an operation schedule is prepared in advance, and each step is performed strictly in accordance with the operation schedule.

10. The construction method of a steel truss bridge across a city road based on modular trailer technology according to claim 1 is characterized in that: In step 8, during the installation of the steel trusses, the steel trusses are unloaded in a stepwise manner with an increment of 20%.

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