Construction structure and method for cantilever erection of upper main pier of high mountain and valley steel truss beam

Abstract

This invention relates to the field of civil engineering technology, and in particular to a construction structure and method for cantilever erection of main piers for steel truss girders in high mountain canyons. Regarding the construction structure, the abutment top is fixed with a three-dimensional jack and abutment pre-height pad; the top of the side span assembly support is fixed with an assembly support pre-height pad; the side span temporary pier top support structure includes a side span temporary pier, with a side span temporary pier pre-height pad fixed on top; the side pier top support structure includes a side pier, with a side pier three-dimensional jack and side pier pre-height pad fixed on top; the secondary side span super-high pier top support structure includes a secondary side span super-high pier, with a pad and hydraulic jack fixed on top; the main pier top support structure includes the main pier, with a main pier three-dimensional jack and main pier pre-height pad fixed on top. The technical solution of this application rationally plans the arrangement of permanent and temporary pier tops. This avoids the need for beam lowering construction at each permanent and temporary pier, greatly shortening the cantilever erection period and reducing the safety risks associated with beam lowering.

Description

Technical Field

[0001] This invention relates to the field of civil engineering technology, and in particular to a construction structure and method for cantilever erection of a main pier using a steel truss beam in a high mountain canyon. Background Technology

[0002] When constructing steel bridges in high mountains and canyons using the cantilever erection method with scaffolding, the elevation of the steel truss beam is consistent with the design elevation during the erection process. When erecting to the permanent pier, the beam is lowered through the rear support to reduce end deflection and complete the pier construction.

[0003] The conventional method of lowering beams onto piers is theoretically applicable to all cantilever erection projects. However, in actual working conditions, this method is affected by the size of the supports and the span of the cantilever. Each time a beam is lowered, a support point must be found behind the erection direction. During beam lowering, the original support point may need to be shimmed or even the support removed. Since the erection must ensure that the tensile stress of the lower chord of the steel truss meets the bearing capacity requirements, the pre-lowering method (supports and shimming installed later) is not feasible. The construction of the pier from the side pier to the main pier requires at least three processes of shimming removal, beam lowering, and shimming re-shimming. At the same time, due to the relatively small height of the supports, the end deflection reduction effect caused by lowering beams onto piers is greatly affected by the actual construction; the height difference space required for beam lowering may be greater than the support height; the resulting additional jacking and re-increasing of shimming height will prolong the construction period and increase safety risks. Summary of the Invention

[0004] The present invention aims to provide a construction structure and method for cantilever erection of steel truss beams for main piers in high mountain canyons, in order to solve the aforementioned technical problems of cumbersome construction and high safety risks in existing technologies.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A construction structure for cantilever erection of a steel truss girder on a main pier in a high mountain canyon includes an abutment support structure, a side span assembly support pier support structure, a side span temporary pier support structure, a side pier support structure, a secondary side span ultra-high pier support structure, and a main pier support structure, arranged sequentially along the slope towards the middle of the canyon.

[0007] in,

[0008] The abutment support structure includes a fixedly installed three-dimensional abutment jack and a pre-height pad for the abutment.

[0009] The side span assembly support pier top support structure includes a fixedly installed assembly support pre-height pad;

[0010] The temporary pier support structure for the side span includes a fixedly installed pre-height pad for the temporary pier in the side span.

[0011] The side pier support structure includes a fixedly installed three-dimensional jack for the side pier and a pre-height pad for the side pier.

[0012] The secondary side span ultra-high pier top support structure includes a fixedly installed pad and hydraulic jack;

[0013] The main pier support structure includes a fixed three-dimensional jack for the main pier and a pre-height pad for the main pier.

[0014] Preferably, the abutment top support structure further includes abutment; the abutment top is provided as a fixed foundation for the abutment three-dimensional jack and the abutment pre-height pad;

[0015] The side span assembly support pier top support structure also includes a side span assembly support; the pre-height pad of the assembly support is fixed on the top of the side span assembly support;

[0016] The temporary pier top support structure of the side span also includes a temporary pier of the side span; the temporary pier of the side span is pre-heightened and fixed to the top of the temporary pier of the side span;

[0017] The side pier top support structure also includes a side pier; the top of the side pier is set as a fixed foundation for the side pier three-dimensional jack and the side pier pre-height pad;

[0018] The secondary side span ultra-high pier top support structure also includes the secondary side span ultra-high pier; the top of the secondary side span ultra-high pier is set as a fixed foundation for the pad and hydraulic jack;

[0019] The main pier top support structure also includes the main pier; the top of the main pier is set as a fixed foundation for the main pier three-dimensional jack and the main pier pre-height pad.

[0020] Preferably, the pad is an elastic-plastic pad.

[0021] Preferably, the abutment top is also fixed with abutment support.

[0022] Preferably, the top of the side pier is also fixed with a side pier support.

[0023] Preferably, the top of the main pier is also fixed with a main pier support.

[0024] On the other hand, the technical solution adopted by the present invention is as follows:

[0025] A construction method for cantilever erection of a steel truss girder on a main pier in a high mountain canyon includes the following steps:

[0026] S1. Calculate the deflection of the steel truss beam under the working conditions of the upper pier, the upper super-high pier, and the upper main pier, and select the height of each level of the pre-height pad at the top of each pier.

[0027] S2. Arrange a three-dimensional jack and a pre-height pad of the first level on the top of the abutment;

[0028] The first-level height pre-height pads for the assembly support are arranged on top of the side span assembly support;

[0029] The first level of height of the temporary pier top of the side span is arranged as a pre-height pad for the temporary pier of the side span;

[0030] Three-dimensional jacks are installed on the top of the side piers;

[0031] The steel truss girder is erected from the abutment to the side pier;

[0032] S3. The side pier is lifted by three-dimensional jacks, and the first level of side pier pre-height pads are placed on the top of the side pier.

[0033] S4. The steel truss beam is erected from the side pier to the super high pier of the secondary side span; hydraulic jacks are used for jacking, and the first level of padding is placed on the top of the super high pier of the secondary side span.

[0034] S5. The bridge abutment three-dimensional jacks and the side pier three-dimensional jacks are used for lifting. The bridge abutment top is equipped with a bridge abutment support and the second-level bridge abutment pre-elevation pad. The side pier top is equipped with a side pier support and the second-level bridge abutment pre-elevation pad.

[0035] S6. The steel truss girder is erected from the secondary side span super high pier to the main pier, and the main pier three-dimensional jacks are arranged on the top of the main pier.

[0036] S7. The main pier is lifted by three-dimensional jacks, and the main pier support is arranged on the top of the main pier; the main pier is lifted by three-dimensional jacks, and the first-level height of the main pier pre-height pad is arranged on the top of the main pier.

[0037] S8. Unload the three-dimensional jacks on the abutment, the side piers, and the main pier. Remove the pre-height pads on the top of the abutment, the side piers, and the main pier.

[0038] Preferably, in S1, finite element software is used to establish different working conditions, apply loads to calculate the internal forces and deformations of the structure, and perform stress analysis calculations.

[0039] Preferably, in S4, the pad is set as an elastic-plastic pad.

[0040] Preferably, S8 includes the following steps:

[0041] S81, unloading with three-dimensional jacks on the abutment, unloading with three-dimensional jacks on the side pier, unloading the second-level height of the abutment pre-height pad on the top of the abutment, and unloading the second-level height of the side pier pre-height pad on the top of the side pier.

[0042] S82, unloading of the three-dimensional jacks on the abutments, unloading of the three-dimensional jacks on the side piers, unloading of the three-dimensional jacks on the main piers, removal of the pre-height pads on the abutments, removal of the pre-height pads on the side piers, removal of the pre-height pads on the main piers.

[0043] The beneficial effects of this invention are:

[0044] The technical solution of this application reduces the deflection at the ends of the steel beams by gradually jacking up (two jackings) and pre-raising the beams on the permanent piers, effectively reducing the amount of padding work and beam lowering construction, resulting in high construction efficiency and improved safety of the upper piers. The deflection at the ends of the steel truss beams is statistically analyzed for each upper pier condition from the abutment to the main pier. The solution rationally plans the arrangement of the permanent and temporary pier tops. This avoids beam lowering construction on each permanent and temporary pier, resulting in high construction efficiency and significantly shortening the cantilever erection period and reducing the safety risks associated with beam lowering. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the construction structure of the cantilevered erection of the main pier of the steel truss beam in a high mountain canyon according to one embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the arrangement of the bridge abutment top in one embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram showing the arrangement of the pier top of the side span assembly support in one embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the arrangement of the temporary pier tops in one embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of the arrangement of the top of the side pier in one embodiment of the present invention;

[0050] Figure 6 This is a schematic diagram of the arrangement of the super high pier top of the secondary side span in one embodiment of the present invention;

[0051] Figure 7 This is a schematic diagram of the arrangement of the top of the main pier in one embodiment of the present invention;

[0052] Figure 8 This is a schematic diagram of the construction method for cantilever erection of the main pier of a steel truss beam in a high mountain canyon, according to one embodiment of the present invention.

[0053] Figure label:

[0054] 1-Abutment top support structure; 11-Abutment pre-height pad; 12-Abutment three-dimensional jack; 13-Abutment support; 2-Side span assembly support pier top support structure; 21-Assembly support pre-height pad; 3-Side span temporary pier top support structure; 31-Side span temporary pier pre-height pad; 4-Side pier top support structure; 41-Side pier pre-height pad; 42-Side pier three-dimensional jack; 43-Side pier support; 5-Ultra-high pier top support structure; 51-Elastic-plastic pad; 52-Hydraulic jack; 6-Main pier top support structure; 61-Main pier pre-height pad; 62-Main pier three-dimensional jack; 63-Main pier support. Detailed Implementation

[0055] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0056] Please refer to the accompanying drawings. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the disclosed technical content. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0057] Example 1

[0058] Please see Figures 1-7 This invention provides a construction structure for cantilevered erection of a main pier on a steel truss girder in a high mountain canyon. The structure includes, sequentially arranged along the slope towards the center of the canyon, an abutment support structure 1, a side span assembly support pier support structure 2, a side span temporary pier support structure 3, a side pier support structure 4, a secondary side span ultra-high pier support structure 5, and a main pier support structure 6. The abutment support structure 1 includes an abutment, with a three-dimensional jack 12 and a pre-height pad 11 fixed to the top of the abutment. The abutment top serves as a foundation for the three-dimensional jack and the pre-height pad. The side span assembly support pier support structure 2 includes a side span assembly support, with a pre-height pad 21 fixed to the top of the side span assembly support. The side span temporary pier support structure 3 includes a side span temporary pier, with a pre-height pad 31 fixed to the top of the temporary pier. The side pier top support structure 4 includes a side pier, and the top of the side pier is fixed with a three-dimensional jack 42 and a pre-height pad 41; the top of the side pier is set as the fixed foundation for the three-dimensional jack and the pre-height pad.

[0059] The secondary side span super-high pier top support structure 5 includes a secondary side span super-high pier, and a fixed support pad and hydraulic jack 52 are fixed on the top of the secondary side span super-high pier; the top of the secondary side span super-high pier serves as the fixed foundation for the support pad and hydraulic jack. The main pier top support structure 6 includes a main pier, and a main pier three-dimensional jack 62 and a main pier pre-height support pad 61 are fixed on the top of the main pier. The top of the main pier serves as the fixed foundation for the main pier three-dimensional jack and the main pier pre-height support pad.

[0060] The construction structure of the main pier for the cantilever erection of the steel truss girder in this high mountain canyon has been further improved in the following ways:

[0061] A bridge abutment support 13 is also fixed to the top of the abutment. A side pier support 43 is also fixed to the top of the side pier. A main pier support 63 is also fixed to the top of the main pier. The pad is an elastic-plastic pad 51.

[0062] During construction, the bridge abutment top is arranged, including the bridge abutment pre-elevation pad 11, the bridge abutment three-dimensional jack 12, and the bridge abutment support 13.

[0063] The arrangement of the side span assembly support pier top includes the side span assembly support pre-height pad 21.

[0064] Arrange the top of the temporary piers on the side spans; including the pre-height padding of the temporary piers on the side spans 31.

[0065] Arrange the top of the side pier; including the side pier pre-height pad 41, the side pier three-dimensional jack 42 and the side pier support 43.

[0066] Arrange the super-high pier top of the secondary side span; including elasto-plastic pad 51 and hydraulic jack 52.

[0067] Arrange the main pier top; including the main pier pre-height pad 61, the main pier three-dimensional jack 62 and the main pier support 63.

[0068] In the above scheme, the pre-elevation pad is a pad composed of steel sections and steel plates. The pre-elevation pad is used to offset the downward deflection of the front end of the steel beam, so that the pad can be used without lifting when erecting it to the side pier or main pier.

[0069] Example 2

[0070] Please see Figures 1-7 This invention provides a construction method for the construction structure of a steel truss beam cantilever erection of the main pier in a high mountain canyon, including the arrangement of the bridge abutment top, the arrangement of the side span assembly support pier top, the arrangement of the side span temporary pier top, the arrangement of the side pier top, the arrangement of the secondary side span ultra-high pier top, and the arrangement of the main pier top.

[0071] The bridge abutment top arrangement includes a bridge abutment pre-height pad 11, a bridge abutment three-dimensional jack 12, and a bridge abutment support 13. In one embodiment, the bridge abutment three-dimensional jack 12 is composed of a hydraulic jack 52 and a limiting device. The limiting device is a small component welded from steel plates and placed under the jack; it acts as a reaction force to achieve limiting.

[0072] The side span assembly support pier top arrangement includes the assembly support pre-height pad 21.

[0073] The arrangement of the temporary pier top in the side span includes the pre-height padding 31 for the temporary pier in the side span.

[0074] The side pier top arrangement includes a side pier pre-height pad 41, a side pier three-dimensional jack 42, and a side pier support 43. Preferably, the side pier three-dimensional jack 42 is a hydraulic jack 52 with a limiting device. The limiting device is a small component formed by welding steel plates and placed under the jack.

[0075] The ultra-high pier top arrangement includes an elastic-plastic support pad 51 and a hydraulic jack 52. Preferably, the hydraulic jack 52 has a lifting force of not less than 100t. In addition, the elastic-plastic support pad 51 can be a prefabricated bridge bearing.

[0076] The main pier top arrangement includes a main pier pre-height pad 61, a main pier three-dimensional jack 62, and a main pier support 63.

[0077] In the above technical solution, the side length of the pre-height lifting pad is not less than the highest pre-height value. The pre-height lifting pad will have a larger supporting area and a better lifting effect.

[0078] Example 3

[0079] Please see Figures 1-7 This invention provides a construction method for cantilever erection of upper main piers for steel truss beams in high mountain canyons, comprising the following steps:

[0080] S1. Calculate the deflection of the steel truss beam under the working conditions of the upper pier, the upper super-high pier, and the upper main pier, and select the height of each level of the pre-height pad at the top of each pier.

[0081] S2. Arrange a three-dimensional jack 12 and a pre-height pad 11 of the first level on the top of the abutment;

[0082] The first-level height pre-height pad 21 of the assembly support is arranged on the top of the side span assembly support;

[0083] The first-level height of the temporary pier top of the side span is arranged with a pre-height pad 31 for the temporary pier top of the side span;

[0084] 42 three-dimensional jacks are installed on the top of the side pier;

[0085] The steel truss girder is erected from the abutment to the side pier;

[0086] S3, the three-dimensional jacks 42 on the side pier are used for lifting, and the first-level height side pier pre-elevation pads 41 are arranged on the top of the side pier;

[0087] S4. The steel truss beam is erected from the side pier to the super high pier of the secondary side span; 52 hydraulic jacks are used for jacking, and the first level of padding is arranged on the top of the super high pier of the secondary side span.

[0088] S5, 12 three-dimensional jacks for the abutment, 42 three-dimensional jacks for the side pier for lifting, 13 abutment supports and 11 pre-height pads for the second-level abutment on the abutment top, 43 side pier supports and 11 pre-height pads for the second-level abutment on the side pier top.

[0089] S6. The steel truss girder is erected from the secondary side span super high pier to the main pier, and 62 three-dimensional jacks are arranged on the top of the main pier.

[0090] S7. The main pier is lifted by three-dimensional jack 62, and the main pier support 63 is arranged on the top of the main pier; the main pier is lifted by three-dimensional jack 62, and the first-level height main pier pre-elevation pad 61 is arranged on the top of the main pier.

[0091] S8. Unload the 12-stage 3D jacks on the abutment, unload the 42-stage 3D jacks on the side pier, and unload the 62-stage 3D jacks on the main pier. Remove the pre-height pads on the abutment top, the side pier top, and the main pier top.

[0092] In one approach, in S1, finite element software is used to establish different working conditions, apply loads, calculate the internal forces and deformations of the structure, and perform stress analysis calculations.

[0093] Preferably, in S4, the pad is set as an elastic-plastic pad 51.

[0094] In the above technical solution, S8 removes the pre-high-pressure pad in several stages, specifically including the following steps:

[0095] S81, the three-dimensional jack 12 of the abutment is unloaded, the three-dimensional jack 42 of the side pier is unloaded, the abutment pre-elevation pad 11 of the second level height is unloaded on the top of the abutment, and the side pier pre-elevation pad 41 of the second level height is unloaded on the top of the side pier.

[0096] S82, unload the 12-stage 3D jacks on the abutment, unload the 42-stage 3D jacks on the side pier, unload the 62-stage 3D jacks on the main pier, remove the pre-height pads on the abutment top, remove the pre-height pads on the side pier top, and remove the pre-height pads on the main pier top.

[0097] Based on detailed construction step calculations (see Examples 4 and 5), this invention statistically analyzes the deflection of the steel truss girder ends for each pier condition from the abutment to the main pier. The scheme rationally plans the arrangement of permanent and temporary pier tops: (1) Except for the main pier, all other permanent piers (abutments and side piers) are supported first and pre-height pads are set to avoid repeated work of pad removal, support removal and reinstallation when the beam is lowered to the pier, thus shortening the construction period; (2) The main pier is the final condition. Only the main pier position adopts the method of post-support installation and three-dimensional jack lifting to reduce the pad height of all subsequent temporary and permanent piers, thus reducing the safety risks caused by excessive pad height; (3) The pre-height pads are set with graded heights. The adjustment of the graded heights is set as a necessary correction construction for the steel truss girder when the permanent pier is lowered, thus shortening the construction period.

[0098] The above plan can avoid the construction of beam lowering at each permanent pier and temporary pier, greatly shortening the cantilever erection period and reducing the safety risks associated with beam lowering.

[0099] Example 4

[0100] Please see Figures 1-8 This invention provides a construction method for cantilever erection of the upper main pier of a steel truss girder in a high mountain canyon, which is implemented according to the following steps:

[0101] Calculate the downward deflection S4, S5, and S6 of the steel truss girder under the conditions of the upper pier, the upper super-high pier, and the upper main pier. In the calculation and analysis, the vertical downward deformation of the steel truss girder ends is different for the three conditions and is represented by S4, S5, and S6 respectively.

[0102] Based on S4 and S5, the first-level height H1 of the bridge abutment pre-elevation pad 11, the first-level height H1 of the side span assembly support pre-elevation pad 21, the first-level height H1 of the side span temporary pier pre-elevation pad 31, and the first-level height H1 of the side pier pre-elevation pad 41 are selected. Among them, S4 <S5

[0103] Based on S5, the first-level height H5 of the elasto-plastic support pad 51 for the ultra-high pier is selected, and the top height V5 of the elasto-plastic support pad 51 is selected. The corresponding node design elevation V0 is V5. Wherein, V5 = V0 - (S5 + 10) / 1000.

[0104] Based on S6 and the height W6 of the main pier support 63, the second-level height H2 of the abutment pre-elevation pad 11 and the second-level height H2 of the side pier pre-elevation pad 41 are selected. Among them, H2+W6>S6.

[0105] Now we will begin the formal construction process:

[0106] The steel truss girder is erected from the abutment to the side pier. The abutment is equipped with abutment bearings 13 and abutment three-dimensional jacks 12. The abutment pre-height pads 11 with a first-level height H1 are arranged on the upper part of the abutment bearings 13. The pre-height pads 21 with a first-level height H1 are arranged on the top of the side span assembly support. The pre-height pads 31 with a first-level height H1 are arranged on the top of the side span temporary pier. The side pier bearings 43 and side pier three-dimensional jacks 42 are arranged on the top of the side pier.

[0107] Subsequently, the three-dimensional jack 42 of the side pier was used to lift the pier, and the first-level height H1 side pier pre-height pad 41 was placed on the top of the side pier.

[0108] The steel truss beam is erected from the side pier to the super high pier. The super high pier is lifted by hydraulic jack 52 and the first level of elastic-plastic pad 51 with a height of H5 is arranged.

[0109] Subsequently, the three-dimensional jacks 12 for the abutment and 42 for the side pier were used for jacking. The abutment pre-elevation pads 11 with a second height of H2 were placed on the top of the abutment and the side piers.

[0110] The steel truss girder is erected from the super high pier to the main pier, and 62 three-dimensional jacks are arranged on the top of the main pier. ​

[0111] Next, the main pier was lifted by the three-dimensional jack 62, and the main pier support 63 was installed on the top of the main pier.

[0112] The main pier is lifted by 62 three-dimensional jacks, and the first-level height H1 main pier pre-height pad 61 is arranged on the top of the main pier.

[0113] Finally, the three-dimensional jacks 12 on the abutment are unloaded, the three-dimensional jacks 42 on the side piers are unloaded, the abutment pre-height pads 11 with a first-level height H1 are placed on the top of the abutment, and the side pier pre-height pads 41 with a first-level height are placed on the side piers.

[0114] Unload 12 three-dimensional jacks for the abutment, unload 42 three-dimensional jacks for the side pier, unload 62 three-dimensional jacks for the main pier, remove 11 pre-height pads for the abutment, remove 41 pre-height pads for the side pier, and remove 61 pre-height pads for the main pier.

[0115] The construction of the upper main pier is now complete.

[0116] Based on detailed construction step calculations (see Examples 4 and 5), this invention reduces the deflection of the steel beam ends by gradually lifting (two lifting operations) and pre-raising on the permanent pier, effectively reducing the amount of padding work and beam lowering construction, and improving the safety of the upper pier.

[0117] Example 5

[0118] Please see Figures 1-8 This invention provides a specific application of a construction method for cantilever erection of a main pier using a steel truss beam in a high mountain canyon, according to... Figure 8 The process shown is as follows.

[0119] The calculated deflections of the steel truss beams for the upper pier, upper super-high pier, and upper main pier conditions are 87mm, 270mm, and 785mm, respectively.

[0120] Based on the downward deflection of 87mm at the end of the upper pier and 270mm at the end of the upper super-high pier, the first level of the pre-height pad 11 for the abutment is selected as 300mm. The first level of the pre-height pad on the top of the side span assembly support is also selected as 300mm. The first level of the pre-height pad on the top of the temporary pier in the side span is also selected as 300mm. The first level of the pre-height pad on the top of the side pier is also selected as 300mm. It can be seen that 87mm < 270mm < 300mm.

[0121] Based on a height of 270mm, the first-level height of the elastomeric support pad 51 for the ultra-high pier is selected as 440mm. The top height of the elastomeric support pad 51 is 603.49m, corresponding to a node design elevation of 603.75m at 603.49m. 603.49m = 603.75m - 260mm.

[0122] Based on the 785mm height and the 800mm height of the main pier support 63, the second-level height of the abutment pre-height pad 11 is selected as 500mm, the second-level height of the side span assembly support pre-height pad 21 is 500mm, the second-level height of the side span temporary pier pre-height pad 31 is 500mm, and the second-level height of the side pier pre-height pad 41 is 500mm. It can be seen that H2 + W6 > S6.

[0123] The steel truss girder is erected from the abutment to the side pier. Abutment bearings 13 and three-dimensional jacks 12 are arranged on the top of the abutment. A pre-height pad 11 with a first-level height of 300mm is arranged on the upper part of the abutment bearings 13. A pre-height pad 21 with a first-level height of 300mm is arranged on the top of the side span assembly support. A pre-height pad 31 with a first-level height of 300mm is arranged on the top of the side span temporary pier. A side pier bearing 43 and three-dimensional jacks 42 are arranged on the top of the side pier.

[0124] The 42 three-dimensional jacks on the side pier are used for lifting, and the first-level side pier pre-height pad 41 with a height of 300mm is placed on the top of the side pier.

[0125] The steel truss beam is erected from the side pier to the super high pier. The super high pier is lifted by hydraulic jack 52 and a first-level 440mm elastic-plastic pad 51 is placed.

[0126] 12 three-dimensional jacks for the abutment and 42 three-dimensional jacks for the side piers are used for jacking. 11 abutment pre-elevation pads with a second-level height of 500mm are placed on the top of the abutment and 11500mm abutment pre-elevation pads with a second-level height are placed on the top of the side piers.

[0127] The steel truss girder is erected from the super high pier to the main pier, and 62 three-dimensional jacks are arranged on the top of the main pier.

[0128] The main pier is lifted by jack 62 three-dimensional jacks, and the main pier support 63 is arranged on the top of the main pier. The main pier is lifted by jack 62 three-dimensional jacks, and the first-level main pier pre-height pad 61 with a height of 300mm is arranged on the top of the main pier.

[0129] Unload the three-dimensional jack 12 on the abutment and the three-dimensional jack 42 on the side pier. Arrange the first-level abutment pre-elevation pad 11 with a height of 300mm on the top of the abutment and the first-level side pier pre-elevation pad 41 on the side pier.

[0130] Unload 12 three-dimensional jacks for the abutment, unload 42 three-dimensional jacks for the side pier, unload 62 three-dimensional jacks for the main pier, remove 11 pre-height pads for the abutment, remove 41 pre-height pads for the side pier, and remove 61 pre-height pads for the main pier.

[0131] With this, the construction of the upper main pier is complete.

[0132] By employing the technical solution of this invention, during the erection process, because the steel truss girder is in a properly pre-elevated state, except for the main pier, the deflection at the ends of the steel truss girder is less than the pre-elevation value. Therefore, there is no need for subsequent girder lowering or jacking up the pier, directly reducing the construction period of each permanent or temporary pier by 5 days and reducing the cost of jacks for each permanent or temporary pier by at least 20,000 yuan. At the same time, based on calculations and taking advantage of the relatively high height of the main pier support 63, the pre-elevation measure for the main pier is not adopted. This avoids the need for jacking up the main pier and also avoids the risk of overturning due to excessive jacking.

[0133] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A construction method for cantilever erection of a steel truss girder on a main pier in a high mountain canyon, characterized in that, Includes the following steps: S1. Calculate the deflection of the steel truss beam under the working conditions of the upper pier, the upper super-high pier, and the upper main pier, and select the height of each level of the pre-height pad at the top of each pier. S2. Arrange a three-dimensional jack and a pre-height pad of the first level on the top of the abutment; The first-level height pre-height pads for the assembly support are arranged on top of the side span assembly support; The first level of height of the temporary pier top of the side span is arranged as a pre-height pad for the temporary pier of the side span; Three-dimensional jacks are installed on the top of the side piers; The steel truss girder is erected from the abutment to the side pier; S3. The side pier is lifted by three-dimensional jacks, and the first level of side pier pre-height pads are placed on the top of the side pier. S4. The steel truss beam is erected from the side pier to the super high pier of the secondary side span; hydraulic jacks are used for jacking, and the first level of padding is placed on the top of the super high pier of the secondary side span. S5. The bridge abutment three-dimensional jacks and the side pier three-dimensional jacks are used for lifting. The bridge abutment top is equipped with a bridge abutment support and the second-level bridge abutment pre-elevation pad. The side pier top is equipped with a side pier support and the second-level bridge abutment pre-elevation pad. S6. The steel truss girder is erected from the secondary side span super high pier to the main pier, and the main pier three-dimensional jacks are arranged on the top of the main pier. S7. The main pier is lifted by three-dimensional jacks, and the main pier support is arranged on the top of the main pier; the main pier is lifted by three-dimensional jacks, and the first-level height of the main pier pre-height pad is arranged on the top of the main pier. S8. Unload the three-dimensional jacks on the abutment, the side piers, and the main pier. Remove the pre-height pads on the top of the abutment, the side piers, and the main pier.

2. The construction method according to claim 1, characterized in that, In S1, finite element software is used to establish different working conditions, apply loads to calculate the internal forces and deformations of the structure, and perform stress analysis calculations.

3. The construction method according to claim 1, characterized in that, In S4, the pad is set to an elastic-plastic pad.

4. The construction method according to claim 1, characterized in that, S8 includes the following steps: S81, unloading with three-dimensional jacks on the abutment, unloading with three-dimensional jacks on the side pier, unloading the second-level height of the abutment pre-height pad on the top of the abutment, and unloading the second-level height of the side pier pre-height pad on the top of the side pier. S82, unloading of the three-dimensional jacks on the abutments, unloading of the three-dimensional jacks on the side piers, unloading of the three-dimensional jacks on the main piers, removal of the pre-height pads on the abutments, removal of the pre-height pads on the side piers, removal of the pre-height pads on the main piers.

5. The construction method according to claim 1, characterized in that, The construction method employs the following construction structure: It includes the bridge abutment support structure, the side span assembly support pier support structure, the side span temporary pier support structure, the side pier support structure, the secondary side span ultra-high pier support structure, and the main pier support structure, which are arranged sequentially along the slope towards the middle of the canyon. in, The abutment support structure includes a fixedly installed three-dimensional abutment jack and a pre-height pad for the abutment. The side span assembly support pier top support structure includes a fixedly installed assembly support pre-height pad; The temporary pier support structure for the side span includes a fixedly installed pre-height pad for the temporary pier in the side span. The side pier support structure includes a fixedly installed three-dimensional jack for the side pier and a pre-height pad for the side pier. The secondary side span ultra-high pier top support structure includes a fixedly installed pad and hydraulic jack; The main pier support structure includes a fixed three-dimensional jack for the main pier and a pre-height pad for the main pier.

6. The construction method according to claim 5, characterized in that, The abutment support structure also includes the abutment; the abutment top is set as a fixed foundation for the abutment three-dimensional jack and the abutment pre-height pad. The side span assembly support pier top support structure also includes a side span assembly support; the pre-height pad of the assembly support is fixed on the top of the side span assembly support; The temporary pier top support structure of the side span also includes a temporary pier of the side span; the temporary pier of the side span is pre-heightened and fixed to the top of the temporary pier of the side span; The side pier top support structure also includes a side pier; the top of the side pier is set as a fixed foundation for the side pier three-dimensional jack and the side pier pre-height pad; The secondary side span ultra-high pier top support structure also includes the secondary side span ultra-high pier; the top of the secondary side span ultra-high pier is set as a fixed foundation for the pad and hydraulic jack; The main pier top support structure also includes the main pier; the top of the main pier is set as a fixed foundation for the main pier three-dimensional jack and the main pier pre-height pad.

7. The construction method according to claim 6, characterized in that, The forming pad is configured as an elastic-plastic forming pad.

8. The construction method according to claim 6, characterized in that, The abutment is also fixed with abutment supports.

9. The construction method according to claim 6, characterized in that, The top of the pier is also fixed with a pier support.

10. The construction method according to claim 6, characterized in that, The main pier is also fixed with a main pier support.

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