A beam string type foundation pit steel trestle

Abstract

The present application relates to a kind of string beam type foundation pit steel trestle, including column support system, string beam system and bridge deck system, column support system includes column, column pile and support connecting piece, column is provided with intercolumnar support mechanism, intercolumnar support mechanism includes horizontal bracing and scissor brace, string beam system includes upper chord compression bar, steel web bar, steel pull rod, connecting pin and anchoring box, upper chord compression bar is provided with outer extension end plate, bridge deck system includes bearing beam, distribution beam, bridge deck panel and guardrail, bearing beam is provided with second head plate, bearing beam is assembled in upper chord compression bar, distribution beam is assembled in bearing beam, bridge deck panel is assembled in distribution beam, bridge deck panel is welded and laid with patterned non-slip steel plate;The present application applies prestress to steel pull rod in string beam, so that the main force component of steel trestle becomes compression-bending component, with the characteristics of high bearing capacity, small deformation and strong structural stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of foundation pit trestle, and particularly relates to a beam string type foundation pit steel trestle. BACKGROUND

[0002] The foundation pit trestle is a temporary structure composed of beams, plates, columns, column piles, connecting rods and the like, which is used as a transportation channel or a working platform in a foundation pit engineering, can be divided into reinforced concrete trestles, steel trestles and combined trestles according to materials, and can be divided into horizontal trestles and inclined trestles according to vertical arrangement, and there is no relevant industry standard for the foundation pit trestle used in civil construction engineering at present. The foundation pit trestle used in civil construction engineering at present usually adopts a reinforced concrete trestle or a steel trestle. The steel trestle is usually assembled from profile steels into a Bailey frame, a truss beam (Bailey beam) is assembled from the Bailey frame, and the Bailey frames are usually connected by a window frame and fixedly spliced by bolts to form a temporary steel trestle. The reinforced concrete trestle has long construction time, high cost and cannot be recycled. The Bailey beam type trestle has high material consumption, and the Bailey truss has poor bending resistance and bending stiffness in two directions of the cross section, and has the problem of overall lateral instability. When the span is large, special attention should be paid to the overall stability. Therefore, the beam string type foundation pit steel trestle is provided. SUMMARY

[0003] The application aims to provide a beam string type foundation pit steel trestle to solve the problems in the background art.

[0004] To achieve the above technical purposes, the technical scheme adopted by the application is as follows.

[0005] A beam string type foundation pit steel trestle, comprising a column support system, a beam string system and a bridge deck system.

[0006] The column support system comprises columns, column piles and support connecting pieces, the columns are inserted into the inner sides of the column piles, the column piles are assembled with a foundation bottom plate, the columns are provided with water stop steel plates at the foundation bottom plates, the support connecting pieces are arranged at the upper ends of the columns, column-to-column support mechanisms are arranged in the horizontal planes of the columns, the column-to-column support mechanisms comprise horizontal braces and scissors braces, end plates are fixedly arranged at the ends of the horizontal braces and the scissors braces, and the horizontal braces and the scissors braces are fixedly connected with the rectangular patch plates through bolts.

[0007] The beam string system comprises upper chord compression bars, steel web bars, steel pull bars, connecting pins and anchor boxes, both ends of each of the upper chord compression bars are fixedly provided with an outward extending end plate, two outward extending end plates between adjacent upper chord compression bars are fixedly connected through bolts, the end upper chord compression bar is fixedly connected with the anchor box through the outward extending end plate, the lower flange of the upper chord compression bar is fixedly connected with the steel web bar through a bolt, a plurality of steel pull bars are sequentially connected end to end, the lower end of the steel web bar and the adjacent steel pull bar are provided with the connecting pin, the steel pull bars at both ends are respectively assembled and connected with the anchor boxes at both sides, and the outermost anchor box is fixedly assembled with an end support.

[0008] The bridge deck system comprises load bearing beams, distribution beams, bridge deck plates and guardrails, both ends of each of the load bearing beams are fixedly provided with a second end plate, the load bearing beams are fixedly assembled on the upper chord compression bars, a plurality of the distribution beams are uniformly assembled on the upper ends of the load bearing beams, the bridge deck plates are assembled on the upper ends of the distribution beams, a patterned anti-skid steel plate is welded on the upper end of each of the bridge deck plates, the patterned anti-skid steel plate is provided with a circular drainage hole, and the guardrails are assembled on the upper sides of the distribution beams.

[0009] Preferably, the column is a lattice column, and the column comprises four angle steels and four rectangular infill plates.

[0010] Preferably, the support connecting piece comprises a square pressure bearing steel plate, two rectangular connecting plates and a first pin shaft, two corbels are fixedly arranged between the square pressure bearing steel plate and the four angle steels, the two rectangular connecting plates are welded on the upper end of the square pressure bearing steel plate, a circular hole is arranged in the middle of each of the two rectangular connecting plates, and the first pin shaft is assembled in the circular hole.

[0011] Preferably, the lower end of the steel web bar is fixedly provided with a connecting rod, the upper end of the steel web bar is fixedly provided with a flush end plate, the flush end plate is connected with the lower flange of the upper chord compression bar through a bolt, the upper end of the connecting rod is fixedly provided with two flush end plates, the flush end plates at the upper end of the connecting rod are fixedly connected with the steel web bar through bolts, the lower end of the steel web bar is provided with a first end plate, two first ear plates are fixedly arranged on the side edges of the first end plate, U-shaped connecting heads and O-shaped connecting heads are respectively fixedly arranged at the two ends of the steel pull bar, and a second pin shaft is arranged between the U-shaped connecting heads, the O-shaped connecting heads and the two first ear plates of adjacent steel pull bars.

[0012] Preferably, the outermost two ends of the steel pull rod are provided with anchors, the outermost two steel pull rod sleeves are provided with steel sleeves, one side of the anchoring box is fixedly provided with a first connecting plate, a stiffening plate is fixedly arranged between the first connecting plate and the anchoring box, three second ear plates are fixedly arranged on one side of the anchoring box, the three second ear plates and the first connecting plate are respectively located on the two outer sides of the anchoring box, and a third pin shaft matched with the second ear plates is arranged between adjacent anchoring boxes.

[0013] Preferably, the upper flange of the upper chord compression rod is fixedly provided with a first U-shaped fastener through a bolt, and the upper chord compression rod is fixedly connected with the load-bearing beam through the first U-shaped fastener.

[0014] Preferably, the bridge deck is provided with a second connecting plate at both ends and in the middle, the upper end of the load-bearing beam is fixedly provided with a second U-shaped fastener, the bridge deck, the load-bearing beam and the distribution beam are fixedly connected through the second connecting plate and the second U-shaped fastener, and the transverse connection and the longitudinal connection between adjacent bridge decks are fixedly connected through bolts.

[0015] Preferably, the guardrail comprises horizontal rods, vertical rods, foot plates and protective nets, a plurality of the horizontal rods and a plurality of the vertical rods are fixedly and perpendicularly connected with each other, the foot plates and the protective nets are assembled inside the frame formed between the horizontal rods and the vertical rods, and the upper flange of the distribution beam is provided with a sleeve on one side, and the sleeve is insertedly connected with the vertical rods.

[0016] The advantages of the present application are that the present application can design steel trestles with different spans by different arrangement of the steel web members and the steel pull rods and by applying prestress to the steel pull rods, can be combined with different lengths according to the site conditions, and has the advantages of simple system, clear stress, high bearing capacity, small deformation, strong stability, large span, clean and fast assembly, and recyclability, compared with the concrete trestle, has the unique advantages of saving construction time and cost and recyclability, and compared with the bailey beam trestle, has the advantages of simple system, saving construction period, saving materials, large bearing capacity and more stable structure by applying prestress. BRIEF DESCRIPTION OF DRAWINGS

[0017] The present application can be further illustrated by the non-limiting examples shown in the accompanying drawings.

[0018] Figure 1 Fig. 1 is a perspective view of the structure of the present application;

[0019] Figure 2 Fig. 2 is a top view of the structure of the present application;

[0020] Figure 3A structural front view of a beam string type foundation pit steel trestle according to the present application;

[0021] Figure 4 A structural side view of a beam string type foundation pit steel trestle according to the present application;

[0022] Figure 5 A structural schematic view of a central column support system and a column-to-column support mechanism according to the present application;

[0023] Figure 6 A structural schematic view of an anchoring box and an end support according to the present application;

[0024] Figure 7 A structural schematic view of a beam string system according to the present application;

[0025] Figure 8 A structural schematic view of an upper chord compression strut according to the present application;

[0026] Figure 9 A structural schematic view of a steel web member and a steel tension member according to the present application;

[0027] Figure 10 A structural schematic view of a steel tension member according to the present application;

[0028] Figure 11 A structural schematic view of a steel web member and a steel tension member according to the present application;

[0029] Figure 12 A structural schematic view of a steel tension member and an anchoring box according to the present application;

[0030] Figure 13 A structural schematic view of an upper chord compression strut and a load bearing beam according to the present application;

[0031] Figure 14 A structural schematic view of a load bearing beam and a distribution beam according to the present application;

[0032] Figure 15 A structural schematic view of a bridge deck according to the present application;

[0033] Figure 16 A structural schematic view of a bridge deck and a protective fence according to the present application;

[0034] Main component symbols are explained as follows:

[0035] The column 11, the angle steel 111, the rectangular patch 112, the water stop steel plate 113, the column pile 12, the foundation bottom plate 121, the support connecting piece 13, the square bearing steel plate 131, the bracket plate 132, the rectangular connecting plate 133, the first pin shaft 134, the end support 14, the limiting plate 141, the gravel 142, the roadbed box 143, the support pile 144, the horizontal support 15, the scissors support 151, the upper chord compression rod 21, the overhanging end plate 211, the steel web rod 22, the flush end plate 221, the first end plate 222, the first lug plate 223, the steel pull rod 23, the U-shaped connector 231, the O-shaped connector 232, the anchor 233, the steel sleeve 234, the connecting pin 24, the second pin shaft 241, the anchoring box 25, the first connecting plate 251, the stiffener plate 252, the second lug plate 253, the third pin shaft 254, the connecting rod 26, the bearing beam 31, the second end plate 311, the first U-shaped fastener 312, the distribution beam 32, the sleeve 321, the second U-shaped fastener 322, the bridge deck 33, the patterned non-slip steel plate 331, the circular drainage hole 332, the second connecting plate 333, the guardrail 34, the horizontal rod 341, the vertical rod 342, the footboard 343, and the protective net 344. DETAILED DESCRIPTION

[0036] In order for those skilled in the art to better understand the present application, the technical solutions of the present application are further described below in conjunction with the drawings and examples. EMBODIMENT

[0037] The present application is a kind of string beam type foundation pit steel trestle, including column support system, string beam system and bridge deck system.

[0038] As shown in Figure 4 , 5 , the column support system includes column 11, column pile 12 and support connecting piece 13, column 11 is inserted into the inside of column pile 12, column pile 12 is mainly used to bear the steel trestle load transmitted through column 11, and bored pile is used to facilitate the insertion of column 11, column 11 is a lattice column, which includes four angle steels 111 and four rectangular patch 112, the four angle steels 111 and the four rectangular patch 112 are welded at equal intervals to form a square column, column pile 12 is assembled with foundation bottom plate 121, column 11 at the position of foundation bottom plate 121 is provided with water stop steel plate 113, support connecting piece 13 is arranged at the upper end of column 11, support connecting piece 13 includes a square bearing steel plate 131, two rectangular connecting plates 133 and a first pin shaft 134, two bracket plates 132 are fixedly arranged between the square bearing steel plate 131 and the four angle steels 111, two rectangular connecting plates 133 are welded on the upper end of the square bearing steel plate 131, and round holes are formed in the middle of the two rectangular connecting plates 133, and the first pin shaft 134 is assembled in the round holes;

[0039] As shown in Figure 5As shown, the transverse plane of the column 11 is provided with an inter-column support mechanism, which includes a horizontal brace 15 and a scissor brace 151, and end plates 152 are fixedly arranged at the ends of the horizontal brace 15 and the scissor brace 151, and the horizontal brace 15 and the scissor brace 151 are fixedly connected with the rectangular patch plate 112 through bolts, wherein the horizontal brace 15 is an I-shaped steel, and the scissor brace 151 is a channel steel, so as to ensure the stability of the column 11 in the transverse plane;

[0040] As shown in the drawings, Figures 7-12 The beam string system includes upper chord compression bars 21, steel web bars 22, steel pull rods 23, connecting pins 24 and anchoring boxes 25, wherein the upper chord compression bars 21, the steel web bars 22, the steel pull rods 23, the connecting pins 24 and the anchoring boxes 25 integrally form a broken line arch-shaped beam string system in the vertical plane, which is used to bear the vertical load in the vertical plane transmitted to the upper chord compression bars 21 by the bridge deck system through the distribution beams 32 and the load-bearing beams 31, and the outer end plates 211 are fixedly arranged at the two ends of the upper chord compression bars 21, wherein as shown in the drawings, Figure 8 When the single H-shaped steel used for the upper chord compression bars 21 cannot meet the bearing capacity, double-spliced H-shaped steels can be formed by welding or bolting; the upper chord compression bars 21 are compression-bending members mainly bearing the load of the beam string system, and the material thereof is large-section narrow-flange HN-shaped steel, wherein in order to facilitate transportation and lifting installation, the outer end plates 211 are arranged at the two ends thereof, and the upper chord compression bars 21 are large-section H-shaped steels with fixed lengths of 4, 5 or 6 m, and the two outer end plates 211 between adjacent upper chord compression bars 21 are fixedly connected through bolts, wherein the connection position of the outer end plates 211 should avoid the nodes of the steel web bars 22 and the load-bearing beams 31; the end upper chord compression bars 21 are fixedly connected with the anchoring boxes 25 through the outer end plates 211, and the lower flanges of the upper chord compression bars 21 are fixedly connected with the steel web bars 22 through bolts; the steel web bars 22 are lower chord compression members of the beam string system, and the material thereof is middle-flange HM-shaped steel; the steel pull rods 23 are sequentially connected head to tail, and the connecting pins 24 are arranged between the lower ends of the steel web bars 22 and the adjacent steel pull rods 23; and the steel pull rods 23 at the two sides are respectively assembled with the anchoring boxes 25 at the two sides; wherein the vertical span ratio of the beam string system is 1 / 10-1 / 12;

[0041] As shown in the drawings, Figure 6As shown, the outermost anchoring box 25 is fixedly assembled with the end support 14, which is fixedly installed on the reinforced concrete crown beam on the top of the support pile 144, which is the foundation support of the foundation pit. After the anchoring box 25 is arranged on the end support 14, the reinforced concrete limiting plate 141 is poured on the concrete crown beam to limit the displacement of the anchoring box 25. After the entire steel trestle is laid and the steel pull rod 23 at both ends of the steel trestle is prestressed for the second time, the sandstone 142 is used for compacted backfilling at the gap of the end support 14 and the construction slope, and then the roadbed box 143 is laid, wherein the surface elevation of the roadbed box 143 is the same as that of the bridge deck 33, so as to ensure that the steel trestle is consistent with the site elevation outside the foundation pit; wherein the thickness of the limiting plate 141 made of reinforced concrete is preferably greater than 300mm, and the reinforcement is not less than Φ20@100. After pouring the concrete crown beam of the support column 144, the reinforcement is reserved, and then the formwork is poured to pour the reinforced concrete limiting plate 141;

[0042] As shown in Figures 9-11 The lower end of the steel web 22 is fixedly provided with a connecting rod 26, the material of the connecting rod 26 is a small-section I-shaped steel, the upper end of the steel web 22 is fixedly provided with a flush end plate 221, the flush end plate 221 is connected with the lower flange of the upper chord compression rod 21 through bolts, two flush end plates 221 are fixedly arranged at the upper end of the connecting rod 26, the flush end plate 221 at the upper end of the connecting rod 26 is fixedly connected with the steel web 22 through bolts, the lower end of the steel web 22 is provided with a first end plate 222, two first ear plates 223 are fixedly arranged at the side of the first end plate 222, U-shaped connectors 231 and O-shaped connectors 232 are fixedly arranged at both ends of the steel pull rod 23 respectively, a second pin shaft 241 is arranged between the U-shaped connectors 231 and the O-shaped connectors 232 of the adjacent steel pull rod 23 and the two first ear plates 223, the steel pull rod 23 as the lower chord tension member of the cable-stayed beam system is composed of a circular solid rod, a U-shaped connector 231 and an O-shaped connector 232, which is connected with the steel web 22 through the second pin shaft 241 to form a lower chord tension member in the form of a broken line;

[0043] As shown in Figure 12As shown, the end of the outermost two steel pull rods 23 is provided with an anchor 233, and the outermost two steel pull rods 23 is sleeved with a steel sleeve 234; the anchoring box 25 is a rectangular coverless box structure welded by steel plates with equal thickness, a circular hole is formed on one side of the bottom plate for the steel pull rod 23 to pass through, the end steel pull rod 23 passes through the top of the anchoring box 25 at a certain angle and leaves a certain anchoring distance, so as to facilitate the installation of the anchor 233, and the self-compacting concrete is poured after the inside of the anchoring box 25 is smeared with a concrete release agent, the end steel pull rod 23 is prestressed after the concrete reaches the design strength, and then the anchoring is locked through the anchor 233; a first connecting plate 251 is fixed on one side of the anchoring box 25, a stiffener plate 252 is fixed between the first connecting plate 251 and the anchoring box 25, three second ear plates 253 are fixed on one side of the anchoring box 25, the three second ear plates 253 are respectively located on the two outer sides of the anchoring box 25 parallel to the first connecting plate 251, a third pin shaft 254 matched with the second ear plates 253 is arranged between the adjacent anchoring boxes 25, when installing, the outermost steel pull rod 23 is sleeved with the steel sleeve 234 and passes through the anchoring box 25, and the self-compacting concrete is poured in the anchoring box 25, when the steel pull rod 23 is prestressed, the steel pull rod 23 is tensioned and locked for anchoring through the anchor 233, the prestress value of the steel pull rod 23 should match the prestress value when the elastic support point method is calculated, and preferably 60%-75% of the axial force design value of the steel pull rod 23, and the prestress of the steel pull rod 23 should be applied in multiple stages, and through repeated adjustment, the prestressed axial force of each component reaches the design requirement;

[0044] As shown in the figure, Figures 13-14 The bridge deck system includes a load-bearing beam 31, a distribution beam 32, a bridge deck 33, and a guardrail 34, the load-bearing beam 31 is fixedly provided with a second end plate 311 at both ends, the load-bearing beam 31 is fixedly assembled on the upper chord compression rod 21, the load-bearing beam 31 is a transverse stress member for transmitting the stress of the steel trestle system to the upper chord compression rod 21, which is composed of double-spliced welded small-section I-beams, the upper flange of the upper chord compression rod 21 is fixedly provided with a first U-shaped fastener 312 through bolts, the upper chord compression rod 21 is fixedly connected with the load-bearing beam 31 through the first U-shaped fastener 312, a plurality of distribution beams 32 are uniformly assembled on the upper end of the load-bearing beam 31, the distribution beam 32 is used for transmitting the bridge deck 33 to the load-bearing beam 31, and the length thereof should be the center distance of the load-bearing beam 31, that is, the longitudinal connection should be on the center line of the load-bearing beam 31, and the distribution beam 32 is made of medium and small-section I-beams;

[0045] As shown in the figure, Figures 15-16As shown, the bridge deck 33 is assembled on the upper end of the distribution beam 32, the bridge deck 33 is composed of small cross-section I-beams and connecting steels, wherein the I-beams are arranged at equal intervals, the adjacent I-beams are fixedly connected by welding through the connecting steels, the upper end of the bridge deck 33 is welded and laid with the patterned anti-skid steel plate 331, the patterned anti-skid steel plate 331 is provided with the circular drainage hole 332, the guardrail 34 is assembled on the upper side of the distribution beam 32, the bridge deck 33 is provided with the second connecting plate 333 at both ends and the middle part, the upper end of the bearing beam 31 is fixedly provided with the second U-shaped fastener 322, the bridge deck 33, the bearing beam 31 and the distribution beam 32 are fixedly connected through the second connecting plate 333 and the second U-shaped fastener 322, the transverse connection and the longitudinal connection between the adjacent bridge decks 33 are fixedly connected through bolts; the guardrail 34 comprises horizontal rods 341, vertical rods 342, foot plates 343 and protective nets 344, the horizontal rods 341 and the vertical rods 342 are fixedly and perpendicularly connected with each other, the foot plates 343 and the protective nets 344 are assembled inside the frame formed between the horizontal rods 341 and the vertical rods 342, the upper flange of the distribution beam 32 is provided with the sleeve 321, the sleeve 321 is insertedly connected with the vertical rod 342;

[0046] When the steel trestle is constructed and installed:

[0047] ①, the construction of the stand column pile 12 is simultaneously performed with the construction of the engineering pile, the water stop steel plate 113 is welded on the lower side of the stand column 11 and then vertically inserted into the stand column pile 12, the insertion depth needs to meet the design requirements and be less than 3000mm from the base pit surface, then the base pit is excavated to the depth of the support pile 144 crown beam, the end support 14 of the reinforced concrete is constructed, and the support connecting piece 13 is welded on the upper end of the stand column 11;

[0048] ②, the installation of the beam string system should be sequentially performed from the end of one side of the steel trestle to the other end of the steel trestle according to the interval of the stand column 11, when the installation is performed, the beam string system should be installed in parallel and symmetrically according to the center distance of the steel trestle, when the installation is performed, the anchoring box 25 is first installed on the end support 14, the side first connecting plate 251 of the anchoring box 25 is bolted with the outer extension end plate 211 of the end of the upper chord compression rod 21, then the anchoring box 25 on the other side of the upper chord compression rod 21 is installed on the support connecting piece 13 of the stand column 11, and the upper chord compression rod 21 is sequentially installed to the end support 14 at the other side of the steel trestle;

[0049] ③, locally excavate earthwork between two parallel upper chord compression bars 21, the earthwork excavation range and depth should meet the construction requirements of installing steel web bars 22, steel pull rods 23 and connecting rods 26, when installing, the steel web bars 22 are fixed and installed on the lower flanges of the upper chord compression bars 21 through the flat end plates 221 at the upper end by bolts, the lower ends of the steel web bars 22 are connected with the U-shaped connectors 231 and O-shaped connectors 232 of the steel pull rods 23 on both sides through the second pin shafts 241, then the connecting rods 26 are fixed and installed on the upper side of the first end plate 222 at the lower end of the steel web bars 22 by bolts, the steel pull rods 23 at the ends are sleeved with steel sleeves 234, the steel pull rods 23 at the ends are inserted into the anchoring boxes 25, and then self-compacting concrete is poured in the anchoring boxes 25 after applying concrete release agent on the inner side of the anchoring boxes 25;

[0050] ④, install the steel web bars 22, steel pull rods 23 and connecting rods 26 to the other end of the steel trestle according to the step ③ between the columns 11;

[0051] ⑤, after the self-compacting concrete reaches the design strength, the steel pull rods 23 are first stressed by 20% to 40% of the final applied prestress, at this time the steel pull rods 23 are tensioned and locked by anchorage devices 233;

[0052] ⑥, the load-bearing beams 31 arranged at equal intervals are connected with the upper chord compression bars 21 through two parallel first U-shaped fasteners 312 on the upper flanges of the upper chord compression bars 21, the standard parts of the distribution beams 32 and bridge deck slabs 33 are connected through second U-shaped fasteners 322 on the load-bearing beams 31, and the transverse and longitudinal standard parts of the bridge deck slabs 33 are connected by bolt fixation;

[0053] ⑦, the steel pull rods 23 at the ends of the steel trestle are second stressed by 60% to 75% of the final applied prestress, and the steel pull rods are tensioned and locked by anchorage devices 233;

[0054] ⑧, the guardrails 34 are installed again, after the installation is completed, the roadbed boxes 143 are laid on the gap at the end supports 14 and the construction slope, and the roadbed boxes 143 are compacted and backfilled with gravel 142, the surface of the roadbed boxes 143 is at the same level as the surface of the bridge deck slabs 33, and the level of the steel trestle is ensured to be consistent with the level of the site outside the foundation pit;

[0055] ⑨, after the steel trestle is installed, the earthwork is excavated to the bottom level of the foundation pit, and during the excavation process, the horizontal supports 15 and scissors braces 151 in the assembly support are installed according to the excavation depth;

[0056] During the use of the steel trestle, the axial force of the steel pull rods should be monitored, and compensation should be made according to the prestress loss;

[0057] The steel trestle is dismantled and recycled according to the following construction sequence:

[0058] The steel trestle is dismantled and recycled according to the following construction sequence: the steel trestle is dismantled from one end to the other end according to the column spacing;

[0059] 1) After the footboard 343 and the protective net 344 are removed, the horizontal rod 341 and the vertical rod 342 are removed, and then the standard parts of the bridge deck 33, the distribution beam 32 and the bearing beam 31 are removed in sequence;

[0060] 2) A support frame is set up between the upper chord compression rod 21 and the lower floor which has been constructed to ensure the stability of the components during the segmented dismantling of the upper chord compression rod 21;

[0061] 3) After the prestress of the end steel tension rod 23 is released, the connecting rod 26, the steel tension rod 23, the steel web rod 22, the upper chord compression rod 21 and the anchoring box 25 are removed, and then the high-grade self-compacting concrete in the anchoring box 25 is removed;

[0062] 4) After the support connecting piece 13 of the column 11 is cut off, the columns 11 between the floors are cut off respectively;

[0063] 5) Finally, the components of the bridge deck system and the beam string structure system are recycled.

[0064] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought of the present application should be covered by the claims of the present application.

Claims

1. A beam string type foundation pit steel trestle, characterized by: Including column support system, beam string system and bridge deck system; The column support system includes a column, a column pile and a support connector, the column is inserted into the inner side of the column pile, the column pile is equipped with a foundation base plate, the column is provided with a water stop steel plate at the foundation base plate, the support connector is provided at the upper end of the column, and an inter-column support mechanism is provided in the transverse plane of the column. The column is a lattice column, and the column includes four angle steels and four rectangular gusset plates. The four angle steels and the four rectangular gusset plates are welded at equal intervals to form a square column; The inter-column support mechanism includes a horizontal brace and a scissors brace, and the ends of the horizontal brace and the scissors brace are fixed with end plates, and the horizontal brace and the scissors brace are fixedly connected to the rectangular plate by bolts; The tension beam system includes an upper chord compression rod, a steel web rod, a steel tension rod, a connecting pin and an anchor box, both ends of several upper chord compression rods are fixed with an extended end plate, the two extended end plates between adjacent upper chord compression rods are fixedly connected by bolts, the upper chord compression rod at the end is fixedly connected to the anchor box through the extended end plate, the lower flange of the upper chord compression rod is fixedly connected to the steel web rod by bolts, several steel tension rods are connected head to tail in sequence, the connecting pin is provided between the lower end of the steel web rod and the adjacent steel tension rod, the steel tension rods at both ends are respectively assembled and connected with the anchor boxes on both sides, and the outermost anchor box is fixedly assembled with an end support; The bridge deck system includes a load-bearing beam, a distribution beam, a bridge deck and a guardrail. A second head plate is fixed at both ends of the load-bearing beam. The load-bearing beam is fixedly assembled on the upper chord pressure rod. Several distribution beams are evenly assembled on the upper end of the load-bearing beam. The bridge deck is assembled on the upper ends of several distribution beams. The upper end of the bridge deck is welded and paved with a patterned anti-slip steel plate. The patterned anti-slip steel plate is provided with a circular drainage hole. The guardrail is assembled on the upper side of the distribution beam.

2. The beam string type foundation pit steel trestle according to claim 1, characterized in that: The support connecting part includes a square pressure-bearing steel plate, two rectangular connecting plates and a first pin shaft. Two corbel plates are fixed between the square pressure-bearing steel plate and the four angle steels. The two rectangular connecting plates are welded to the upper end of the square pressure-bearing steel plate. A circular hole is opened in the middle of the two rectangular connecting plates, and the first pin shaft is assembled in the circular hole.

3. The beam string type foundation pit steel trestle according to claim 1, characterized in that: The lower end of the steel web is fixed with a connecting rod, and the upper end of the steel web is fixed with a flush end plate, and the flush end plate is connected to the lower flange of the upper chord compression rod by bolts. The upper end of the connecting rod is fixed with two flush end plates, and the flush end plate at the upper end of the connecting rod is fixedly connected to the steel web by bolts. The lower end of the steel web is provided with two first ear plates fixed on the side of the first head plate, and U-shaped connectors and O-shaped connectors are fixed at both ends of the steel pull rod respectively, and a second pin shaft is provided between the U-shaped connectors and O-shaped connectors of adjacent steel pull rods and the two first ear plates.

4. The beam string type foundation pit steel trestle according to claim 1, characterized in that: The two outermost ends of the steel pull rods are provided with anchors, and the two outermost steel pull rod sleeves are provided with steel sleeves. A first connecting plate is fixedly provided on one side of the anchor box, and a stiffening plate is fixedly provided between the first connecting plate and the anchor box. Three second ear plates are fixedly provided on one side of the anchor box, and the three second ear plates and the first connecting plate are respectively located on two outer sides parallel to the anchor box, and a third pin shaft matching several second ear plates is provided between adjacent anchor boxes.

5. The beam string type foundation pit steel trestle according to claim 1, characterized in that: The upper flange of the upper chord compression rod is fixed with a first U-shaped fastener by means of bolts, and the upper chord compression rod is fixedly connected to the load-bearing beam by means of the first U-shaped fastener.

6. The beam string type foundation pit steel trestle according to claim 1, characterized in that: A second connecting plate is provided at both ends and the middle of the bridge deck, and a second U-shaped fastener is fixed to the upper end of the load-bearing beam. The bridge deck, the load-bearing beam and the distribution beam are fixedly connected by the second connecting plate and the second U-shaped fastener, and the transverse and longitudinal connections between adjacent bridge decks are fixed by bolts.

7. The beam string type foundation pit steel trestle according to claim 1, characterized in that: The guardrail includes horizontal rods, vertical rods, footboards and protective nets. Several of the horizontal rods and several of the vertical rods are vertically fixedly connected to each other. The footboards and the protective nets are assembled on the inner side of the frame formed between the horizontal rods and the vertical rods. A sleeve is provided on one side of the upper flange of the distribution beam, and the sleeve is plugged into the vertical rods.

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