A continuous pushing method for a large-span steel beam of a bridge approach without a guide beam

Abstract

The application discloses a kind of bridge approach no guide beam large-span steel beam continuous pushing method, traction point is arranged at the front end of steel beam, pushing jack is arranged on the main bridge tower, and pushing platform is erected on the side of approach bridge away from main bridge, slide beam and lateral limiting device are installed on the top of each pier of approach bridge between pushing platform and approach bridge, then each section steel beam is assembled on pushing platform section by section, traction point and pushing jack are connected using drag steel strand, steel beam pushing construction can be started, temporary cable-stayed tower is installed on the upper end of first-span steel beam, temporary cable-stayed tower is provided with cable-stayed cable anchored and connected with the front end of steel beam, counterweight is arranged at the rear of first-span steel beam, and wind-resistant cable is installed on the both sides of temporary cable-stayed tower on first-span steel beam.The application is reinforced by designing temporary cable-stayed tower on the upper end of first-span steel beam, and realizes no guide beam pushing construction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of bridge construction technology, and particularly relates to a method for continuous incremental launching of a large-span steel beam of an approach bridge without a launching nose. BACKGROUND

[0002] At present, the steel girder installation construction of a large-span combined I-beam steel bridge is mostly carried out by using the launching nose continuous incremental launching method, the bridge erecting machine whole-hole installation method, the support installation method, the large-section steel beam lifting installation method and the like. From the applicability comparison of the above commonly used construction methods under the conditions of mountainous areas, it can be seen that, for the construction of a fabricated combined girder steel bridge in a mountainous area with relatively inconvenient traffic organization conditions and terrain conditions, the launching nose incremental launching method and the bridge erecting machine whole-hole installation method both have good terrain applicability and construction period efficiency, but due to the specificity of the launching nose and the bridge erecting machine, the standardization degree of the construction method is relatively insufficient, and due to the rapid increase of the rental cost of the bridge erecting machine, the comprehensive economy and applicability of the launching nose incremental launching method are superior to those of the bridge erecting machine whole-hole installation method. However, the traditional launching nose incremental launching method has problems such as long construction period occupied by the installation and removal of the launching nose, non-universality of the launching nose, high safety risk of high-altitude operation and the like.

[0003] In view of the above, it is necessary to improve the existing incremental launching method. SUMMARY

[0004] The main purpose of the present application is to provide a method for continuous incremental launching of a large-span steel beam of an approach bridge without a launching nose, which reinforces the first-span steel beam by designing a temporary cable-stayed tower at the upper end of the first-span steel beam, and thus realizes the incremental launching construction without a launching nose, reduces the workload of high-altitude operation and reduces the operation risk of construction personnel.

[0005] Therefore, the method for continuous incremental launching of a large-span steel beam of an approach bridge without a launching nose provided by the present application is constructed by using the incremental launching method without a launching nose, the incremental launching direction is uphill, the traction point is arranged at the front end of the steel beam, the incremental launching jack is arranged on the main bridge tower, the incremental launching platform is arranged on the side of the approach bridge away from the main bridge, after the completion of the arrangement of the incremental launching platform, the slide beam and the lateral limiting device are arranged on the top of each pier of the approach bridge, the slide block is arranged on the slide beam, each section of the steel beam is assembled on the incremental launching platform, the traction point and the incremental launching jack are connected by using the pulling steel strand, and the incremental launching construction of the steel beam can be started.

[0006] In the method, the temporary cable-stayed tower is arranged at the upper end of the first-span steel beam, the cable-stayed cable anchored and connected with the front end of the steel beam is arranged on the temporary cable-stayed tower, the counterweight is arranged at the rear part of the first-span steel beam, and the wind-resistant cable is arranged on both sides of the temporary cable-stayed tower on the first-span steel beam, and the two ends of the wind-resistant cable are anchored and connected with the temporary cable-stayed tower and the first-span steel beam, respectively.

[0007] Specifically, the temporary cable-stayed tower is arranged symmetrically along the longitudinal center line of the first cross steel beam, and a plurality of the temporary cable-stayed towers are arranged on the front and rear sides of each of the temporary cable-stayed towers from top to bottom.

[0008] The cable (9) located on the front side is anchored and connected with the front end of the steel beam.

[0009] The cable (9) located on the rear side is anchored and connected with the rear end of the steel beam.

[0010] Specifically, the wind-resistant cables are arranged in groups along the longitudinal direction of the approach bridge, each group including two wind-resistant cables arranged in cross, one end of each of the two wind-resistant cables being connected with the two sides of the first cross steel beam, and the other end of each of the two wind-resistant cables being connected with the two outermost temporary cable-stayed towers on the first cross steel beam.

[0011] Specifically, a tower antenna is arranged on the approach bridge in a front-high and rear-low inclined manner, two ends of the tower antenna being fixedly connected with the jacking platform and the main bridge tower respectively, a suspension pulley being slidingly installed on the tower antenna, and a pulling steel strand being fixedly connected with the suspension pulley, the pulling steel strand being laid out through the laying-out frame on the jacking platform when the pulling steel strand is erected, and a driving mechanism driving the suspension pulley and the pulling steel strand to move towards the jacking jack, so as to realize the erection of the pulling steel strand.

[0012] Specifically, the driving mechanism includes a pulley traction cable, a first fixed pulley being arranged on the main bridge tower at a fixed position of the tower antenna, a second fixed pulley being arranged on the jacking platform at the fixed position of the tower antenna, one end of the pulley traction cable being wound on a first winch on the jacking jack fixed pier after passing through the first fixed pulley, the other end of the pulley traction cable being wound on a second winch on the jacking platform after passing through the second fixed pulley, forming a single-line reciprocating traction system, and the suspension pulley being fixedly connected with the pulley traction cable.

[0013] Specifically, an inter-column cable is connected between adjacent piers, after the steel beam is jacked to a certain pier, one end of the inter-column cable is anchored on the pier by using an anchor and a clamping piece, and the inter-column cable is tensioned at the next pier, so as to realize the self-balancing of the force between the piers during the jacking of the steel beam.

[0014] Specifically, after the steel beam is jacked into place, the beam lowering construction is performed, and a beam lowering jack is symmetrically arranged at each beam lowering support point.

[0015] Specifically, after jacking a certain distance, the sliding block needs to be reversed, and the reversing time of the sliding block on the jacking platform and the pier top of each pier is when the sliding block is about to slide out of the sliding beam, and at least two sliding blocks are ensured on each sliding beam to ensure the stability of the steel beam at the sliding block contact position.

[0016] Specifically, the steel beams of left and right spans are synchronously assembled and jacked, one set of counterforce support and two jacking jacks are arranged for each span.

[0017] Specifically, the slide beams on the jacking platform are arranged in a discrete manner, N slide beams are arranged along the longitudinal direction, and after the installation of the slide beams on the jacking platform, obvious beam segment assembling and positioning marks are set on the jacking platform at the slide beams by using paint, which are used for steel beam assembling and positioning.

[0018] Compared with the prior art, the embodiment has the following beneficial effects: the temporary cable-stayed tower is designed on the upper end of the first-span steel beam, the cable-stayed cable connected with the front end of the steel beam is arranged on the temporary cable-stayed tower, and the counterweight is arranged at the rear part of the first-span steel beam, so that the large cantilever part of the front part of the first-span steel beam has sufficient structural rigidity, and the wind-resistant cable is arranged on the first-span steel beam on both sides of the temporary cable-stayed tower, so that the jacking construction without the guide beam is achieved, the workload of high-altitude operation is greatly reduced, and the operation risk of the construction personnel is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0020] Figure 1 is a schematic view of the continuous jacking of the approach bridge large-span steel beam without the guide beam provided by the embodiment of the present application;

[0021] Figure 2 is a schematic view of the first-span steel beam structure provided by the embodiment of the present application;

[0022] Figure 3 is a schematic view of the erection of the drag steel strand provided by the embodiment of the present application;

[0023] Figure 4 is a schematic view of the jacking process of the steel beam in the engineering case provided by the embodiment of the present application;

[0024] 1, jacking jack; 2, bridge tower; 3, jacking platform; 4, pier; 5, slide beam; 6, sliding block; 7, drag steel strand; 8, temporary cable-stayed tower; 9, cable-stayed cable; 10, erection antenna; 11, suspension pulley; 12, first-span steel beam; 13, pulley traction cable; 14, first fixed pulley; 15, second fixed pulley; 16, first winch; 17, second winch; 18, inter-column cable; 19, beam lowering jack; 20, wind-resistant cable. DETAILED DESCRIPTION

[0025] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0026] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0027] In addition, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0028] Referring to Figures 1-3 A continuous pushing method for a large-span steel beam of a bridge approach without a guide beam, which adopts a pulling type pushing process without a guide beam, and the pushing direction is uphill. The traction point is arranged at the front end of the steel beam, the pushing jack 1 is arranged on the main bridge tower 2, the pushing platform 3 is arranged on the side away from the main bridge of the bridge approach, after the pushing platform 3 is arranged, the sliding beam 5 and the lateral limiting device are arranged on the pushing platform 3 and the top of each pier 4 of the bridge approach, and the sliding block 6 is arranged on the sliding beam, then each section of the steel beam is assembled on the pushing platform 3 in sections, the traction point and the pushing jack 1 are connected by the pulling steel strand 7, and the pushing construction of the steel beam can be started, wherein the temporary cable-stayed tower 8 is arranged at the upper end of the first-span steel beam 12, the cable-stayed cable 9 connected with the front end of the steel beam is arranged on the temporary cable-stayed tower 8, the counterweight is arranged at the rear part of the first-span steel beam 12, and the wind-resistant cable 20 is arranged on both sides of the temporary cable-stayed tower 8 on the first-span steel beam 12, and the two ends of the wind-resistant cable 20 are respectively anchored to the temporary cable-stayed tower 8 and the first-span steel beam 12.

[0029] The application ensures that the large cantilever part of the front part of the first-span steel beam 12 has sufficient structural rigidity by designing temporary cable-stayed towers 8 at the upper end of the first-span steel beam 12, pulling the front part of the first-span steel beam 12 by cable-stayed cables 9, and designing counterweights at the rear part of the first-span steel beam 12, and by installing wind-resistant cables 20 on the first-span steel beam 12 at both sides of the temporary cable-stayed towers 8, so as to achieve construction without guide beams, which not only reduces the workload of high-altitude operation, but also reduces the operation risk of construction personnel.

[0030] To further ensure the safety of the pushing, the temporary cable-stayed towers 8 are arranged in a center-symmetrical manner along the longitudinal center line of the first-span steel beam 12, a plurality of cable-stayed cables are arranged on the front and rear sides of each temporary cable-stayed tower 8 from top to bottom, the cable-stayed cables 9 on the front side are anchored and connected to the front end of the steel beam, the cable-stayed cables 9 on the rear side are anchored and connected to the rear end of the steel beam, the wind-resistant cables 20 are arranged in a plurality of groups along the longitudinal direction of the approach bridge, each group includes two wind-resistant cables 20 arranged in a cross manner, one end of the two wind-resistant cables 20 arranged in a cross manner is connected to the two sides of the first-span steel beam 12, respectively, and the other end is connected to the two outermost temporary cable-stayed towers 8 on the first-span steel beam 12, respectively.

[0031] The above-mentioned continuous pushing method of the large-span steel beam of the approach bridge without guide beams includes the following steps:

[0032] 1. Pushing platform erection

[0033] The pushing platform 3 is arranged at the position of the 3*40m cast-in-place box girder bridge span, and is in the form of pier top bracket+pier side steel pipe truss pier+bailey beam. When the steel beam is assembled and pushed, the 5mm steel plate is laid on the surface layer of the platform as a manual operation platform. When a car is needed, a 3.5m wide 2cm thick steel plate channel is separately laid at the pier axis as a car transportation channel. After the pushing construction is completed, the 5mm steel plate surface layer is removed, the 10cm*10cm square wood is used as a distribution beam, and the 12mm thick bamboo plywood is laid on the distribution beam as a cast-in-place box girder construction bottom mold.

[0034] 2. Cable-stayed tower erection

[0035] Referring to Figure 2, each of the left and right steel beams is provided with a group of cable-stayed tower, the cable-stayed tower uses steel pipe column short tower as support point support, the beam end uses steel strand cable-stayed cable to be tensioned and hung, the front end length is 53m, the rear end length is 42m, the height is 15m, the short tower uses Φ630 steel pipe, is arranged according to longitudinal 2 columns, transverse 4 rows, the tower height is 15m;The cable-stayed cable is arranged according to longitudinal 4 columns, transverse 4 rows, is respectively T1-T4, uses 5 bundles Φs / 15.2 steel strand, cross-sectional area Ap=695mm2, elastic modulus Ep=1.95×105MPa, tensile strength standard value fpk=1860MPa, and the initial tension control force is respectively: TI=230KN, T2=228KN, T3=235KN, T4=275KN. In order to strengthen the steel beam jacking wind resistance, 6 groups of wind cables 20 are arranged between the cable tower and the steel beam, the wind cable 20 uses 6×19+FC-1770MPa φ30mm steel wire rope, is arranged in cross, is respectively K1-K6, and the arrangement interval with the front end of the steel beam is respectively: K1=13m, K2=29m, K3=45m, K4=73m, K5=89m, K6=105m, uses saddle type rope clamp anchoring, and the recommended value of the initial fastening force of the wind cable 20 is: K1=12kN, K2=9kN, K3=4kN, K4=8kN, K5=12kN, K6=14kN.

[0036] In order to install the short tower cable, the cable anchorage point is arranged on the steel beam, the anchorage point is a triangular anchor box structure, is formed by welding 2cm thick steel plate, and the weld height is 16mm, is processed and manufactured with the steel beam in the steel beam manufacturing plant. The upper flange connected with the column needs to be treated with variable width, and the two sides are widened by 15cm, a total of 30cm. The cable tower anchoring end uses JYM15-5 P type anchor, the tensioning end uses YJM15-5 anchor, the cable-stayed short tower uses 13, 15 tower crane to be hoisted and erected, when erecting, the steel pipe is installed from bottom to top, and the flat link and the inclined brace are installed in time after a section of steel pipe column is erected. The flat link and the inclined brace are strictly prohibited to be lifted without being installed.

[0037] 3. Slide beam installation

[0038] The slide beams 5 on the pushing platform 3 are arranged in discrete form with a longitudinal spacing of 10 m, and 12 slides are arranged along the longitudinal direction. The slide beams 5 on the platform are used as assembling pedestals, and after the installation of the slide beams 5 on the platform, obvious beam segment assembling positioning marks are set on the platform at the slide by using paint, which are used for steel beam assembling positioning and are convenient for checking the assembling plane position. It is required that the elevation difference of all adjacent slides in the transverse direction is consistent with the design, and the vertical curve pushing requires that the slide is in an ideal circular curve. Moreover, all the slides must be adjusted to be parallel to the pushing track before installation, so that the surface contact between the steel beam, the sliding block 6 and the slide beam 5 is ensured during the pushing process. Therefore, the control requirements of the slide elevation and the levelness are quite high, and errors and large measurement errors are not allowed. The slide beams 5 are arranged in the form of discontinuous steel combination. Since the bridge has slopes in the transverse and longitudinal directions on the beam bottom, transverse and longitudinal slope adjusting pads need to be arranged respectively. After the pushing is completed, only the front and tail sections are used as temporary supports for the beam lowering and the beam lowering jack 19 switching support.

[0039] The stainless steel plate is laid on the top surface of the slide beam 5, the slide on the pier top uses 8 mm thick stainless steel belt, and the slide on the pushing platform 3 uses 5 mm stainless steel belt. The surface roughness of the continuous slide is less than Ra5μm. The following points should be noted when laying the stainless steel plate:

[0040] 1. The edge of the stainless steel top surface is treated by edge covering to avoid damaging the slide plate and to reduce the bulging phenomenon during the pushing process due to poor welding.

[0041] 2. Before laying the stainless steel plate on the top surface of the slide beam 5, the joint welds should be polished smooth to increase the flatness of the top surface of the slide beam 5.

[0042] 3. The stainless steel plate is continuously arranged with intermittent openings in the middle, the entire sliding surface should be kept continuous, the side welding uses intermittent continuous welding, and the welds at the top abutment should be continuously welded and polished smooth.

[0043] 4. If the friction and traction of the slide beam 5 cannot be completely balanced during the pushing process, it will be transmitted to the platform pipe pile and affect the stability of the platform. Therefore, the slide beam 5 is fixed to the cap beam on each pier top through the counter-anchor steel plate, and the slide on the pushing platform 3 is welded to the platform steel distribution beam.

[0044] 4. Installation of lateral limiting device

[0045] In order to prevent the steel beam from having a large axis deviation during the pushing process, a lateral limiting device is arranged on the slides on both sides of the steel beam. The device is composed of 2 cm Q235A steel plates, is inserted into a φ90 mm steel rod, and is limited by a φ110*5.3 mm PE pipe. The maximum limiting distance of one side is 10 cm. When the axis deviation of the steel beam reaches 5 cm, a jack can be used to correct the deviation by using the steel rod as a counterforce point.

[0046] 5. Design of sliding block

[0047] To ensure the smooth progress of the steel beam on the slide beam 5, the slide block 6 is placed between the slide beam 5 and the steel beam to allow the steel beam to move forward under the action of the pushing jack 1. The thickness of the slide block 6 is affected by the thickness of the splice plate of the steel beam bottom plate and needs to be selected according to the thickness of the splice plate and the height of the nut. According to the design drawing, when the thickness of the steel beam bottom plate is 32mm and 40mm, the P5 splice plate and the T2 filler plate are connected by M30 bolts, the thickness of the P5 plate is 24mm, the thickness of the T2 plate is 8mm, and the height of the M30 bolt nut is 18.6mm. That is, the total height difference of the bottom plate connection is 24+8+18.6=54.6mm, so the thickness of the slide block 6 should be greater than 54.6mm, and the thickness of the slide block 6 is 60mm in this project.

[0048] Because the MGE sliding slide has low friction coefficient and small difference between dynamic and static friction coefficients (K=0.06), it will not appear crawling phenomenon and run smoothly, so the slide block 6 is selected as MGE slide block 6, which has grooves on the surface and is coated with lubricant to reduce the friction coefficient. The size is 700x350x60mm, and the weight of a single block is about 24.99kg. During the pushing process of the steel beam, the plate must be fed in time, and it is necessary to ensure that there are always 2 groups (2 blocks per group) of slide blocks 6 on the slide beam 5. Before the steel beam is about to be pushed into place, the position of the slide block 6 is calculated to ensure that the front and rear slide blocks 6 fall on the front and rear slide beams 5 to facilitate the removal of the middle slide beam 5.

[0049] In addition, to prevent the slide block 6 from popping out when the end of the slide block 6 is separated from the slide when pushing, the end of the slide block 6 is designed as an arc to improve the problem of change of deflection pressure at the front end of the steel beam during pushing.

[0050] 6, installation of pushing jacks 1 and counterforce supports

[0051] Referring to Figure 1 DYSC350D-300 type pushing jacks 1 are arranged on the cross beam of the main bridge tower 2 on the side of the middle span, and the jacks are arranged on the counterforce supports to provide the pushing force for the steel beam to move forward. One set of supports and two jacks are arranged on each span, and two sets of supports and four jacks are arranged on the whole bridge.

[0052] The pushing jack 1 is a DYSC350D-300 type, with a rated pushing weight of 358.5t, and a structure of a through-core type, with a steel strand as a pushing cable. The wedge-shaped anchor at both ends of the pushing jack 1 has a one-way self-locking function. When the anchor is working (tight), the steel strand is automatically locked; when the anchor is not working (loose), the steel strand is released, and the steel strand can move up and down. One process of the hydraulic pushing process is one stroke of the pushing jack 1. When the pushing jack 1 repeats the cycle, the pushed object moves step by step forward. During the pushing process of the pushing jack 1, the top must be reserved with the steel strand. If too much steel strand is reserved, it will have a great influence on the operation of the steel strand during the pushing process and the locking and opening of the anchor of the pushing jack 1. Therefore, each pushing jack 1 must be configured with a guide frame in advance to facilitate the smooth guide of the reserved excess steel strand at the top. The excess steel strand can be freely guided backward and downward along the pushing platform 3. The guide frame is installed behind the hydraulic pushing device, and the guide direction of the guide frame is based on the principle of facilitating the installation of oil pipes, sensors and not affecting the free falling of the steel strand.

[0053] Because the steel strand is long, the steel strand is first placed on the assembly platform end, pulled to the pushing device end through the erection of a traction system, and then passed through the connecting anchor. The steel strand cannot be dislocated, knotted or twisted as a whole. The exposed section of each steel strand should be as flat as possible, and the upper end of the steel strand should be fixed by a clamp and an anchor piece.

[0054] In order to ensure the stability of the steel beam structure during the pushing process and the accuracy of the positioning of the pushing unit structure, the lifting points of the steel beam structure body always maintain synchronization (±20mm) during the lifting or lowering process. In view of the above construction difficulties, the following control measures are taken: the hydraulic pushing jacks 1 arranged at the oblique pulling points on the bridge tower 2 are connected in series and parallel on the pump of the hydraulic numerical control pump station. Each set of hydraulic numerical control pump station is provided with two pumps.

[0055] 7. Erection of the pulling steel strand

[0056] Referring to Figure 3 An erection antenna 10 is arranged on the approach bridge in a front-high and rear-low inclined manner. The two ends of the erection antenna 10 are fixedly connected with the pushing platform 3 and the main bridge tower 2 respectively. A hanging pulley 11 is slidingly installed on the erection antenna 10. The pulling steel strand 7 is fixedly connected with the hanging pulley 11. When the pulling steel strand 7 is erected, the pulling steel strand 7 is placed on the cable placing frame on the pushing platform 3. The driving mechanism drives the hanging pulley 11 and the pulling steel strand 7 to move towards the pushing jack 1, so as to realize the erection of the pulling steel strand 7.

[0057] Specifically, the driving mechanism includes a pulley traction cable 13, a first fixed pulley 14 is arranged on the main bridge tower 2 at the fixed position of the erecting antenna 10, a second fixed pulley 15 is arranged on the pushing platform 3 at the fixed position of the erecting antenna 10, one end of the pulley traction cable 13 is wound on a first winch 16 on the fixed pier of the pushing jack 1 after passing through the first fixed pulley 14, the other end is wound on a second winch 17 on the pushing platform 3 after passing through the second fixed pulley 15, forming a single-line reciprocating traction system, the suspension pulley 11 is fixedly connected with the pulley traction cable 13, the pulling steel strand 7 is arranged to erect the antenna 10, and the pulling steel strand 7 is suspended to avoid damage caused by rubbing with the pier column during erection.

[0058] The pulling steel strand 7 is pulled during erection, one at a time, the steel strand anchoring end adopts a JYM15-19 P-type fixed-end anchor (P-type anchor plate, extrusion sleeve and extrusion spring), the pushing and tensioning end adopts a YJM15-19 type anchor (working anchor plate and clamping piece), the antenna and the pulley traction cable 13 are all erected by artificial + tower crane connection transmission.

[0059] 8. Pier-to-pier cable 18 erection

[0060] Referring to Figure 1 , 6 to 13# piers are each provided with 2 bundles of 3φs15.2 1870MPa steel strand pier-to-pier cables 18, each with a tensioning force of 20kN, after the pushing beam reaches the Nth pier, the steel strand is anchored by a YM15-3 anchor and clamping piece, and the steel strand is tensioned at the N-1th pier tensioning end, so as to realize self-balancing of the force between the piers during steel beam pushing, and the pier-to-pier cable 18 is erected by the erecting antenna 10.

[0061] Specifically, after each pushing distance, the sliding block 6 needs to be reversed, and the reversing time of the sliding block 6 on the pushing platform 3 and each pier top of the pier 4 is when the sliding block 6 is about to slide out of the sliding beam 5, and at least 2 sliding blocks 6 are ensured on each sliding beam 5 to ensure the stability of the steel beam at the contact position of the sliding block 6, and the steel beams of the left and right spans are assembled and pushed synchronously, one set of counter-force support is arranged for each span, and 2 pushing jacks 1 are arranged.

[0062] The steel beam pushing process of the scheme will be described in detail below in combination with a specific engineering case

[0063] The pushing length of the bridge approach pushing construction is 480m, and 8 spans each with a length of 60m are pushed, that is, the pushing is divided into 8 pushing rounds, each round pushes 60m, and each pushing segment is taken as a construction step, and the subsequent steel beam segments are installed according to the step.

[0064] The prefabricated bridge deck component is prefabricated and stored in the bridge deck processing area, and is transported to the bridge deck by a cannon car for installation span by span after the pushing beam is completed.

[0065] Referring toFigure 4 In particular, the pushing process of the bridge includes the following steps:

[0066] Step one:

[0067] 1. The construction of the lower tower column of the 5# bridge tower is completed;

[0068] 2. The construction of the pier platform of the 6#-16# bridge pier is completed.

[0069] Step two:

[0070] 1. The pushing platform support is erected, and the pushing platform construction is completed;

[0071] 2. The corresponding load or trial lifting operation is performed;

[0072] 3. The sliding beam is installed on the pushing platform, and the sliding block is installed on the sliding beam;

[0073] 4. The pier top bracket, beam jacking jack, sliding beam, and lateral limiting device are installed on the top of the 6#-13# pier;

[0074] 5. The steel beam assembly gantry crane is installed;

[0075] Step three:

[0076] 1. The first 11 segments of the 5th and 6th spans are hoisted and spliced using the gantry crane;

[0077] 2. The cable-stayed tower, stay cable, and wind-resistant cable are installed on the top chord of the installed 5th and 6th span steel beams;

[0078] 3. Within the range of 60-120 meters behind the cable-stayed tower, the bridge deck slab is used for weighting in the direction of the abutment, with 2 blocks of bridge deck slab configured transversely every 10m.

[0079] Step four:

[0080] 1. One segment length (10.91m) is pushed forward;

[0081] 2. Check if the pushing system is operating normally;

[0082] 3. Check the beam body monitoring data.

[0083] Step five:

[0084] 1. After checking and confirming that there are no abnormal conditions, continue to push forward 2 segment lengths, splice 12 to 14 segments;

[0085] 2. Complete the counterweight

[0086] Step six:

[0087] 1. Push forward, and pause when the front end of the first segment is pushed to the center line position of the 12# pier;

[0088] 2, the completion of a cross-steel beam length, check the cable tower, cable system and check the beam monitoring data;

[0089] Step seven:

[0090] 1, continue to push, when the first segment front push to 11# pier center line position pause;

[0091] 2, the portal crane system forward to the 14 to 15 cross;

[0092] 3, 16 cross as a rod piece yard.

[0093] Step eight:

[0094] 1, continue to assemble the 15th to 18th segment;

[0095] Step nine:

[0096] 1, continue to push, when the first segment front push to 10# pier center line position pause;

[0097] Step ten:

[0098] 1, the assembly of step eight and step nine, the process of pushing;

[0099] 2, push to the right place.

[0100] Step eleven:

[0101] 1, install the beam support;

[0102] 2, remove the cable tower, cable, wind cable, pushing and sliding system (sliding beam and slider);

[0103] 3, the first multi-point synchronous beam;

[0104] 4, install 5-12 bridge deck and pouring wet joint;

[0105] 5, the second multi-point synchronous beam.

[0106] Any of the above technical solutions disclosed by the present application, unless otherwise stated, if it discloses a numerical range, the disclosed numerical range is a preferred numerical range, any person skilled in the art should understand: the preferred numerical range is only one of the many values that can be implemented, the technical effect is more obvious or representative. Because there are many values, it is impossible to enumerate, therefore, the present application discloses some values to illustrate the technical solutions of the present application, and the above-mentioned values should not constitute a limitation on the protection scope of the present application.

[0107] Meanwhile, if the present application discloses or involves mutually fixedly connected parts or structural members, unless otherwise stated, the fixed connection can be understood as: detachably fixed connection (for example, using bolt or screw connection), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, integrally formed by using casting process) (obviously, except for the cases where integral forming process cannot be used).

[0108] In addition, the terms used to represent the positional relationship or shape in any of the technical solutions disclosed in the present application include the approximate, similar or close state or shape, unless otherwise stated. Any component provided by the present application can be assembled from multiple individual components or manufactured as a single component by integral forming process.

[0109] The above embodiments are only examples for clearly illustrating the present application, and are not limitations on the embodiments. Based on the above description, other different forms of changes or variations can also be made by those skilled in the art. Here, it is neither necessary nor possible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for continuous jacking of large-span steel beams without guide beams for approach bridges, characterized in that: The construction process adopts the guide beam-less drag-type jacking method. The jacking direction is uphill. The traction point is set at the front end of the steel beam. The jacking jack (1) is set on the main bridge tower (2). The jacking platform (3) is erected on the side of the approach bridge away from the main bridge. After the jacking platform (3) is erected, the sliding beam (5) and the lateral limiting device are installed on the top of the jacking platform (3) and each pier (4) of the approach bridge. The slider (6) is installed on the sliding beam. Then, each segment of the steel beam is assembled on the jacking platform (3). The traction point and the jacking jack (1) are connected by the drag steel strand (7). The jacking construction of the steel beam can then begin. A temporary cable-stayed tower (8) is installed at the upper end of the first span steel beam (12). The temporary cable-stayed tower (8) is provided with cable stays (9) that are anchored to the front end of the steel beam. A counterweight is provided at the rear of the first span steel beam (12). At the same time, wind-resistant cables (20) are installed on both sides of the temporary cable-stayed tower (8) on the first span steel beam (12). The two ends of the wind-resistant cables (20) are anchored to the temporary cable-stayed tower (8) and the first span steel beam (12) respectively. An antenna (10) with a high front and low rear is erected above the approach bridge. The two ends of the antenna (10) are fixedly connected to the jacking platform (3) and the main bridge tower (2) respectively. A suspension pulley (11) is slidably installed on the antenna (10). The drag steel strand (7) is fixedly connected to the suspension pulley (11). When the drag steel strand (7) is erected, the drag steel strand (7) is released through the cable release frame on the jacking platform (3). The drive mechanism drives the suspension pulley (11) and the drag steel strand (7) to move toward the jacking jack (1) to realize the erection of the drag steel strand (7). The driving mechanism includes a pulley traction cable (13). A first fixed pulley (14) is provided on the main bridge tower (2) at the fixed position of the erected antenna (10). A second fixed pulley (15) is provided on the jacking platform (3) at the fixed position of the erected antenna (10). One end of the pulley traction cable (13) passes around the first fixed pulley (14) and is wound around the first winch (16) on the fixed pier of the jacking jack (1). The other end passes around the second fixed pulley (15) and is wound around the second winch (17) on the jacking platform (3), forming a single-line reciprocating traction system. The suspension pulley (11) is fixedly connected to the pulley traction cable (13).

2. The continuous jacking method for large-span steel beams without guide beams for approach bridges according to claim 1, characterized in that: Multiple temporary cable-stayed towers (8) are arranged symmetrically along the longitudinal centerline of the first span steel beam (12), and each temporary cable-stayed tower (8) has multiple stay cables installed from top to bottom on its front and rear sides; wherein, The cable (9) located on the front side is anchored to the front end of the steel beam; The cable (9) located on the rear side is anchored to the rear end of the steel beam.

3. The continuous jacking method for large-span steel beams without guide beams for approach bridges according to claim 2, characterized in that: The wind-resistant cables (20) are arranged in several groups along the longitudinal direction of the approach bridge. Each group includes two wind-resistant cables arranged in a cross pattern. One end of the two wind-resistant cables (20) arranged in a cross pattern is connected to both sides of the first span steel beam (12), and the other end is connected to the two outermost temporary cable-stayed towers (8) on the first span steel beam (12).

4. The continuous jacking method for large-span steel beams without guide beams for approach bridges according to claim 1, characterized in that: Inter-column cables (18) are connected between adjacent piers (4). After the steel beam is pushed to a certain pier (4), anchors and clamps are used to anchor one end of the inter-column cable (18) to the pier (4), and the inter-column cable (18) is tensioned at the next pier (4) to achieve self-balance of forces between piers (4) during the pushing of the steel beam.

5. The continuous jacking method for large-span steel beams without guide beams for approach bridges according to claim 1, characterized in that: After the steel beam is pushed into place, the beam is lowered. A beam lowering jack is symmetrically set at each beam lowering support point (19).

6. The continuous jacking method for large-span steel beams without guide beams for approach bridges according to claim 1, characterized in that: After each push is made a certain distance, the slider (6) needs to be replaced. The timing for replacing the slider (6) on the top of the jacking platform (3) and each pier (4) is when the slider (6) is about to slide out of the slide beam (5), and ensure that there are at least 2 sliders (6) on each slide beam (5) to ensure the stability of the steel beam at the contact point of the slider (6).

7. The continuous jacking method for large-span steel beams without guide beams for approach bridges according to claim 1, characterized in that: The left and right steel beams are assembled and pushed simultaneously, with one set of reaction support and two jacks installed for each beam (1).

8. The continuous jacking method for large-span steel beams without guide beams for approach bridges according to claim 1, characterized in that: The slide beams (5) on the jacking platform (3) are set in a discrete manner, with a total of N tracks along the longitudinal direction. After the slide beams (5) on the jacking platform (3) are installed, obvious beam segment assembly positioning marks are set on the jacking platform (3) at the slide beams (5) using paint for steel beam assembly positioning.

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