Construction method of temporary supporting system during pier replacement of existing bridge

Abstract

The invention belongs to the technical field of bridge construction, and relates to a construction method of a temporary supporting system during pier replacement of an existing bridge. The method comprises the steps that a construction area near an original pier is hardened and leveled; construction of a foundation platform is conducted on the ground on the two longitudinal sides of the original pier, and a plurality of supporting bases are pre-buried in the foundation platform; two sets of steel pipe supports are arranged below bridge spans on the two longitudinal sides of an original pier respectively, and each set of steel pipe support comprises a front row of steel pipe frames and a rear row of steel pipe frames. A set of jacking system is mounted at the top of each front row of steel pipe frames, and the top surface of the jacking system is in compression joint with the bottom surface of the T-shaped beam so as to jack a bridge span, temporarily support the bridge span after jacking and fall the bridge span after pier replacement; a set of emergency jacking system is mounted at the top of each row of steel pipe frames, and a safety gap is reserved between the top surface of the emergency jacking system and the bottom surface of the T-shaped beam. A stable and reliable temporary supporting system can be provided for pier replacement of the existing bridge, the construction safety during pier replacement is ensured, and the construction difficulty of the temporary supporting system is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge construction, and in particular relates to a construction method of a temporary support system when replacing piers of an existing bridge. Background Art

[0002] With the construction and development of highway bridges, existing bridges may need to be replaced for maintenance, renovation, or to avoid new bridges. Figure 1 , Figure 2 As shown, existing bridges generally include an upper structure, a lower structure and a support 3; the upper structure is also called a span 1, and many spans 1 are composed of multiple T-beams 11; the lower structure includes piers 2 and foundations, wherein many piers 2 are double-column frame piers, including two oppositely arranged piers 21, a cap beam 22 connected to the top ends of the two piers 21, and at least one tie beam 23 connected between the two piers 21, and a plurality of support pads 24 are provided on the top surface of the cap beam 22; a plurality of supports 3 are installed one by one on the support pads 24, and the supports 3 are force transmission devices at the support points of the span 1 and the piers 2.

[0003] When replacing piers, a temporary support system is usually set up near the original pier 2 of the existing bridge, and the temporary support system is used to lift the ends of the front and rear spans 1 above the original pier 2, so that the front and rear spans 1 are separated from the original pier 2, and the lifted span 1 is temporarily supported. Then the original pier 2 is demolished, and new piers are built after demolition, and the front and rear spans 1 are placed on the new piers by using the temporary support system to realize the pier replacement construction of the existing bridge. It can be seen that the temporary support system will directly affect the construction safety of the existing bridge when replacing piers. In addition, when constructing the temporary support system, it may face limitations such as large clearance under the existing bridge and narrow site, making it difficult to support large hoisting equipment for hoisting operations during construction, resulting in the construction of the temporary support system being more difficult, the construction difficulty is greater, and the construction safety is poor. Summary of the invention

[0004] In view of the deficiencies existing in the related art, the present invention provides a construction method for a temporary support system when replacing piers of an existing bridge.

[0005] The present invention provides a construction method of a temporary support system when replacing piers of an existing bridge, comprising the following steps:

[0006] Construction site preparation: Harden and level the construction area near the original piers of the existing bridge;

[0007] Temporary support foundation construction: construct the foundation cap on the ground on both sides of the original bridge pier, and embed multiple support seats in the top surface of the foundation cap;

[0008] Installation of steel pipe brackets: A set of steel pipe brackets is respectively installed under the bridge spans on both sides of the original bridge piers in the longitudinal direction. Each set of steel pipe brackets includes a front row of steel pipe brackets close to the original bridge piers and a rear row of steel pipe brackets far away from the original bridge piers. The front and rear rows of steel pipe brackets are connected to each other and their bottoms are connected to the support seat;

[0009] Installation of jacking system: A jacking system is installed on the top of each of the two front steel pipe racks. The top surfaces of the two jacking systems are respectively pressed against the bottom surfaces of the T-beams of the bridge spans above them, and are used for jacking the bridge spans, temporary support after jacking, and falling back after pier replacement.

[0010] Installation of emergency jacking support system: One set of emergency jacking support system is installed on the top of each of the two rear steel pipe racks, and a safety gap is reserved between the top surface of the two sets of emergency jacking support systems and the bottom surface of the T-beam of the bridge span above them.

[0011] In some of the embodiments, the temporary support foundation construction steps include, first, measuring and placing the plane positions of multiple pile foundations on the ground on both sides of the original bridge pier in the longitudinal direction, and constructing the pile foundation; then excavating the foundation pit, erecting the pedestal formwork, tying the pedestal reinforcement, and pouring the foundation pedestal. When pouring the foundation pedestal, multiple support seats are pre-buried in the top surface of the foundation pedestal; each support seat is evenly provided with multiple bolts, and the top ends of the bolts protrude from the top surface of the foundation pedestal.

[0012] In some of the embodiments, the pile foundation is a rock-embedded pile, and the depth of the pile foundation embedded in the bedrock is not less than 3 times the pile diameter of the pile foundation.

[0013] In some of the embodiments, each row of steel pipe racks includes a plurality of steel pipe columns arranged at intervals laterally; the jacking system includes a first crossbeam, a first pad beam and a plurality of jacks; the first crossbeam is connected to the top surfaces of all steel pipe columns of the front row of steel pipe racks; a plurality of jacks are arranged laterally on the top surface of the first crossbeam, wherein a jack is correspondingly provided under the web of each T-beam of the bridge span, and a further jack is provided in addition to the two outermost jacks; the first pad beam is crimped onto the top surfaces of all the jacks; a plurality of first pad blocks are arranged laterally on the top surface of the first pad beam, and the first pad blocks are used to be crimped to the bottom surface of the T-beam of the bridge span above it.

[0014] In some of the embodiments, a limit block is protruded from the top surface at both ends of each first cushion beam, and the two limit blocks are respectively abutted against the horseshoe outer side surfaces of the T-beams at both ends of the bridge span above the first cushion beam.

[0015] In some of the embodiments, the emergency support system includes a second cross beam, a second cushion beam and a plurality of support blocks. The second cross beam is connected to the top surfaces of all steel pipe columns of the rear row of steel pipe racks. A plurality of support blocks are transversely arranged on the top surface of the second cross beam. The second cushion beam is crimped on the top surfaces of all support blocks. A plurality of second cushion blocks are transversely arranged on the top surface of the second cushion beam. A safety gap is reserved between the second cushion block and the bottom surface of the T-beam of the bridge span above it.

[0016] In some of the embodiments, a safety gap of 15 mm to 20 mm is reserved between the top surface of each emergency supporting system and the bottom surface of the T-beam of the bridge span above it.

[0017] In some of the embodiments, each steel pipe column includes a plurality of vertically connected steel pipe segments; parallel joints and diagonal braces are connected between each two adjacent steel pipe segments in the transverse direction and the longitudinal direction of the front and rear rows of steel pipe racks.

[0018] In some of the embodiments, when installing the steel pipe support, the jacking system and the emergency jacking system, the following steps are also included:

[0019] A crane is set up near the original bridge pier under the bridge, and the steel pipe column is installed in sections by the crane. After the steel pipe sections at the same height are installed, the parallel joints and diagonal braces between two adjacent steel pipe sections in the horizontal and vertical directions are installed immediately until the installation of the steel pipe bracket within the crane's lifting height range is completed;

[0020] A hoisting system is arranged on the bridge span, and the hoisting system includes a traveling frame and a hoisting frame; the traveling frame spans across the existing bridge deck and can move back and forth in the longitudinal direction, and two hoisting winches are arranged laterally on the traveling frame; the hoisting frame is arranged laterally below the bridge span, and its two lateral ends are respectively connected to the two hoisting winches by lifting ropes, and an electric gantry vehicle that can move back and forth laterally along the hoisting frame is connected below the hoisting frame; the remaining steel pipe segments are installed by cooperating with the crane under the bridge and the hoisting system on the bridge, thereby completing the installation of the steel pipe bracket that exceeds the hoisting height range of the crane, and then the first crossbeam, the first cushion beam, the second crossbeam and the second cushion beam on the steel pipe bracket are installed.

[0021] Based on the above technical scheme, the construction method of the temporary support system when replacing piers of an existing bridge in the embodiment of the present invention can provide a stable and reliable temporary support system for replacing piers of an existing bridge, ensure the construction safety when replacing piers of an existing bridge, and reduce the construction difficulty of the temporary support system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 This is the cross-sectional elevation of the existing bridge;

[0024] Figure 2 This is the longitudinal elevation of the existing bridge;

[0025] Figure 3 It is a flow chart of the construction method of the temporary support system when replacing piers of an existing bridge according to the present invention;

[0026] Figure 4 A plan view of a temporary support foundation in the present invention;

[0027] Figure 5 It is a horizontal elevation view of the temporary support foundation in the present invention;

[0028] Figure 6 It is a horizontal and vertical relationship diagram of the temporary support system in the present invention and the existing bridge;

[0029] Figure 7 It is a longitudinal elevation relationship diagram of the temporary support system in the present invention and the existing bridge;

[0030] Figure 8 It is a planar relationship diagram of the temporary support system and the original bridge pier in the present invention;

[0031] Fig. 9 It is a horizontal and vertical relationship diagram of the jacking system in the present invention and the existing bridge;

[0032] Fig.10 A longitudinal elevation diagram showing the relationship between the jacking system of the present invention and the existing bridge;

[0033] Fig.11 A plan view showing the relationship between the jacking system of the present invention and the existing bridge;

[0034] Fig.12 It is a horizontal and vertical relationship diagram of the hoisting system of the present invention and the existing bridge;

[0035] Fig.13 It is a longitudinal elevation relationship diagram of the hoisting system in the present invention and the existing bridge.

[0036] In the figure: 1, bridge span; 11, T-beam; 2, bridge pier; 21, pier column; 22, cap beam; 23, tie beam; 24, bearing pad stone; 3, bearing; 4, temporary support system; 41, temporary support foundation; 411, pile foundation; 412, foundation pedestal; 413, support seat; 414, bolt; 42, steel pipe bracket; 421, front steel pipe rack; 422, rear steel pipe rack; 423, steel pipe column; 4231, steel pipe segment; 424, flat joint; 425, inclined Supporting parts; 43. Lifting system; 431. First cross beam; 432. First cushion beam; 433. Jack; 434. First cushion block; 435. Limiting block; 44. Emergency jacking system; 441. Second cross beam; 442. Second cushion beam; 443. Second cushion block; 444. Support block; 5. Hoisting system; 51. Traveling frame; 52. Hoisting frame; 53. Hoisting winch; 54. Electric gantry; 55. Lifting rope; 56. Traveling track; 57. Traveling trolley. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be understood that the terms "center", "lateral", "longitudinal", "up", "down", "top", "bottom", "inside", "outside", "left", "right", "front", "back", "vertical", "horizontal", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] The terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] refer to Figure 1-Figure 13 As shown, the present invention provides a construction method for a temporary support system when replacing piers of an existing bridge, including the steps of preparing a construction site, constructing a temporary support foundation 41, installing a steel pipe support 42, installing a jacking system 43, and installing an emergency jacking system 44.

[0042] The construction site preparation steps include building a temporary access road according to the site layout diagram, pouring plain concrete in the construction area near the original pier 2 of the existing bridge to harden and level it, so as to provide conditions for the entry of construction machinery and materials in the next step; clarifying the site elevation of the area where the temporary support system 4 is located, and taking measures to drain the site.

[0043] The construction steps of the temporary support foundation 41 include constructing a foundation pedestal 412 on the ground on both longitudinal sides of the original pier 2 of the existing bridge, and the foundation pedestals 412 on both sides can be connected as one, and multiple support seats 413 are pre-buried in the top surface of the foundation pedestal 412.

[0044] The installation steps of the steel pipe support 42 include: setting a set of steel pipe supports 42 respectively under the bridge span 1 on both sides of the original bridge pier 2 in the longitudinal direction, each set of steel pipe supports 42 includes a front row of steel pipe frames 421 close to the original bridge pier 2 and a rear row of steel pipe frames 422 away from the original bridge pier 2, that is, the front and rear rows of steel pipe frames are arranged longitudinally; the front and rear rows of steel pipe frames are connected to each other and their bottoms are installed on the foundation pedestal 412, specifically, the bottoms of the front and rear rows of steel pipe frames are connected to the support seat 413.

[0045] The installation steps of the jacking system 43 include installing a jacking system 43 on the top of the two front steel pipe racks 421, and the top surfaces of the two jacking systems 43 are respectively pressed against the bottom surfaces of the T-beams 11 of the bridge spans 1 above them; the two jacking systems 43 are used to jack up the ends of the two bridge spans 1 on both sides of the longitudinal direction of the original bridge piers 2, temporarily support them after jacking, and lower them after replacing the piers.

[0046] The installation steps of the emergency jacking system 44 include installing one set of emergency jacking system 44 on the top of the two rear steel pipe racks 422, respectively, and reserving a safety gap between the top surfaces of the two emergency jacking systems 44 and the bottom surfaces of the T beams 11 of the upper span 1. It is further explained that when the existing bridge pier replacement construction is carried out normally, the emergency jacking system 44 does not contact the span 1. If the jacking system 43 on the front steel pipe rack 421 fails unexpectedly and the temporary support fails and the span 1 drops, the emergency jacking system 44 on the rear steel pipe rack 422 can quickly participate in the support to avoid the risk of possible collapse of the bridge and ensure the safety of construction.

[0047] The above-mentioned schematic embodiment, through the construction of the foundation pedestal 412 and the support seat 413, can provide a solid and stable installation foundation for the steel pipe support 42, and realize a stable connection between the steel pipe support 42 and the temporary support foundation 41; through the setting of the jacking system 43 on the front steel pipe frame 421, it is possible to realize the jacking, temporary support and fall back of the front and rear spans 1 above the original pier 2; through the setting of the emergency jacking system 44 on the rear steel pipe frame 422, it is possible to realize the emergency support reserve for the span 1; therefore, this schematic embodiment can provide a stable and reliable temporary support system 4 for replacing piers of existing bridges, and ensure the construction safety when replacing piers of existing bridges.

[0048] refer to Figure 3-Figure 8 As shown, in some embodiments, the construction steps of the temporary support foundation 41 include, first, according to the existing bridge centerline and the plane layout of the temporary support foundation 41, a measurement control network is established on the construction ground on both sides of the original bridge pier 2 in the longitudinal direction, and the plane positions of multiple pile foundations 411 of the temporary support foundation 41 are measured and placed on the construction ground according to the control network, and the pile foundations 411 are staggered. After the construction of the pile foundation 411 is completed, the foundation pit is excavated, the head of the pile foundation 411 is chiseled off, the foundation formwork is supported, the foundation steel bars are tied, and the foundation foundation 412 is poured in layers. When pouring the foundation foundation 412, multiple support seats 413 are pre-buried in the top surface of the foundation foundation 412; the construction process of the pile foundation 411 and the foundation foundation 412 is well known to those skilled in the art, and will not be expanded or elaborated here. Furthermore, a plurality of bolts 414 are evenly arranged on each support seat 413, the top of the bolt 414 protrudes from the top surface of the foundation pedestal 412, and the bottom of the bolt 414 is buried in the foundation pedestal 412; the plurality of support seats 413 are connected to the steel pipe bracket 42 through the bolts 414. This exemplary embodiment refines the construction steps of the temporary support foundation 41, improves the bearing capacity of the construction ground, and improves the installation stability of the steel pipe bracket 42, thereby enabling the temporary support system 4 to provide stable and safe temporary support for the bridge span 1.

[0049] In some embodiments, the pile foundation 411 is a rock-embedded pile, and the depth of the pile foundation 411 embedded in the bedrock is not less than 3 times the pile diameter of the pile foundation 411, thereby ensuring the structural strength of the foundation pedestal 412 and further ensuring the installation strength and stability of the steel pipe support 42 thereon.

[0050] refer to Figure 6-Figure 11As shown, in some embodiments, each row of steel pipe racks includes a plurality of steel pipe columns 423 arranged at intervals in a transverse direction; the steel pipe columns 423 are connected to the support seats 413 pre-buried on the temporary support foundation 41 in a one-to-one correspondence. The jacking system 43 includes a first crossbeam 431, a first cushion beam 432 and a plurality of jacks 433; the first crossbeam 431 is connected to the top surfaces of all steel pipe columns 423 of the front row of steel pipe racks 421; a plurality of jacks 433 are arranged transversely on the top surface of the first crossbeam 431, wherein a jack 433 is correspondingly arranged under the web of each T-beam 11 of the span 1, and because the span 1 also has a relatively high anti-collision wall structure on both sides of the span 1, a jack 433 is also arranged at a preset transverse distance in addition to the two jacks 433 corresponding to the webs of the two outermost T-beams 11 of the span 1; the first cushion beam 432 is crimped onto the top surfaces of all the jacks 433; a plurality of first cushion blocks 434 are arranged transversely on the top surface of the first cushion beam 432, and the first cushion blocks 434 are used to be crimped to the bottom surface of the T-beam 11 of the span 1 above it. When performing the lifting step of the bridge span 1, the jack 433 is started to lift it upward, which can push the first cushion beam 432 and the first cushion block 434 thereon to move upward, thereby lifting the bridge span 1; when performing the lowering step of the bridge span 1, the jack 433 is started to lower it, and the first cushion beam 432 and the first cushion block 434 thereon are lowered accordingly, thereby lowering the lifted bridge span 1. This exemplary embodiment refines the arrangement of the lifting system 43 to ensure that the lifting system 43 can smoothly lift and lower the bridge span 1.

[0051] refer to Fig. 9 As shown, in some embodiments, a stopper 435 is protruded on the top surface of each transverse end of each first cushion beam 432, and the two stopper blocks 435 are respectively abutted against the horseshoe outer side surfaces of the T beams 11 at the transverse ends of the bridge span above the first cushion beam 432. In this exemplary embodiment, by setting the stopper blocks 435 on the first cushion beam 432 of the two sets of steel pipe brackets 42, it is ensured that the ends of the two spans 1 on both sides of the original bridge pier 2 will not move laterally relative to the first cushion beam 432 during the entire period from being lifted to falling back, and it is ensured that the two spans 1 above the original bridge pier 2 will not move laterally due to non-active correction during the entire pier replacement construction, and it is ensured that the existing bridge as a whole will not suffer secondary damage due to lifting.

[0052] refer to Figure 6-Figure 11As shown, in some embodiments, the emergency support system 44 includes a second cross beam 441, a second cushion beam 442 and a plurality of support blocks 444; the second cross beam 441 is connected to the top surface of all steel pipe columns 423 of the rear steel pipe frame 422; a plurality of support blocks 444 are arranged transversely on the top surface of the second cross beam 441; the second cushion beam 442 is crimped on the top surfaces of all support blocks 444, and a plurality of second cushion blocks 443 are arranged transversely on the top surface of the second cushion beam 442, and a safety gap is reserved between the second cushion block 443 and the bottom surface of the T beam 11 of the bridge span 1 above it; when the existing bridge pier replacement construction is carried out normally, the second cushion block 443 is in a virtual connection state without contacting the bridge span 1. Reference Fig.10 As shown, in some embodiments, the safety gap L reserved between the top surface of each emergency support system 44 and the bottom surface of the T beam 11 of the bridge span 1 above it is 15mm-20mm. This exemplary embodiment refines the arrangement of the emergency support system 44 to ensure that the emergency support system 44 can play an emergency support reserve role for the bridge span 1.

[0053] refer to Figure 6-Figure 11 As shown, in some embodiments, each steel pipe column 423 includes a plurality of steel pipe segments 4231 connected vertically; that is, the steel pipe column 423 is processed in sections according to a preset height, and flanges are provided at both ends of the steel pipe segments 4231 for connection. The steel pipe segments 4231 adjacent to each other in the transverse direction and in the longitudinal direction of the front and rear rows of steel pipe racks are connected with parallel joints 424 and diagonal braces 425, and the connection forms include but are not limited to welding or bolt connection, thereby connecting the front and rear rows of steel pipe racks into a whole, realizing the integrity of the steel pipe bracket 42, and thus ensuring the structural strength and stability of the steel pipe bracket 42. Furthermore, an operating platform is set up at the position where the steel pipe bracket 42 needs to be operated by personnel, and a ladder or stairs are set up to facilitate the passage of personnel up and down.

[0054] refer to Figure 6-Figure 13 As shown, in some embodiments, when installing the steel pipe support 42, the jacking system 43 and the emergency jacking system 44, the following steps are also included:

[0055] A crane is set up near the original bridge pier 2 under the bridge, and the steel pipe column 423 is installed in sections by the crane. After the installation of the steel pipe segments 4231 at the same height is completed, the parallel joints 424 and the diagonal braces 425 between the adjacent steel pipe segments 4231 in the horizontal direction and the vertical direction are immediately installed until the installation of the steel pipe bracket 42 within the crane hoisting height range is completed; further, the steel pipe segments 4231 are bolted with flange high-strength bolts, and the verticality and overall plane position of the steel pipe column 423 are checked every time a steel pipe segment 4231 is installed;

[0056] A hoisting system 5 is arranged on the bridge span 1, and the hoisting system 5 includes a traveling frame 51 and a hoisting frame 52 in a truss structure; the traveling frame 51 spans across the existing bridge deck and can move back and forth in the longitudinal direction. Specifically, a traveling track 56 extending longitudinally is arranged on both sides of the existing bridge deck in the transverse direction, and a traveling trolley 57 is installed on the traveling track 56. The traveling frame 51 is carried on the traveling trolley 57, and the traveling trolley 57 moves along the traveling track 56 to drive the traveling frame 51 to move back and forth in the longitudinal direction; two hoisting winches 53 are arranged in the transverse direction on the traveling frame 51; the hoisting frame 52 is arranged in the transverse direction below the bridge span 1, and its transverse ends are respectively connected to the two hoisting winches 53 by hanging ropes 55, and an electric truss car 54 that can move back and forth in the transverse direction along the hoisting frame 52 is connected below the hoisting frame 52, and the electric truss car 54 is used to hoist the parts to be installed; it can be seen that the longitudinal position of the parts to be installed can be adjusted by moving the traveling frame 51 The hoisting winch 53 can be used to adjust the lifting height of the parts to be installed, and the movement of the electric gantry 54 can be used to adjust the lateral position of the parts to be installed; further, the remaining steel pipe segments 4231 are installed by the cooperation of the crane under the bridge and the hoisting system 5 on the bridge, that is, the steel pipe segments 4231 are first lifted to a certain height by the crane and then transferred to the electric gantry 54, and then the hoisting system 5 completes the installation of the steel pipe bracket 42 that exceeds the lifting height range of the crane; after the installation of the steel pipe bracket 42 is completed, the first crossbeam 431, the first cushion beam 432, the second crossbeam 441 and the second cushion beam 442 thereon are installed; it should be noted that due to the large sizes of the first crossbeam 431, the first cushion beam 432, the second crossbeam 441 and the second cushion beam 442, they are first assembled into a whole under the bridge, and then the crane under the bridge and the hoisting system 5 on the bridge cooperate with each other to hoist them into place one by one.

[0057] It can be understood that after the first pad beam 432 and the second pad beam 442 are installed, the exact height difference between the first pad beam 432 and the second pad beam 442 and the bottom surface of the T beam 11 is measured immediately, and the first pad block 434 is made according to the line shape of the T beam 11 and supported between the first pad beam 432 and the bottom surface of the T beam 11, and the second pad block 443 is made and installed on the second pad beam 442; when the line shape of the T beam 11 is a diagonal line, the first pad block 434 and the second pad block 443 are wedge-shaped pads.

[0058] It is further explained that stress and strain observation points need to be set at the stress characteristic parts of the steel pipe support 42, and the strain gauges need to be connected to the computer terminal; the stress and deformation of the temporary support system 4 are monitored throughout the construction process to ensure construction safety.

[0059] The above-mentioned schematic embodiment realizes the convenient installation of the steel pipe support 42 and the jacking system 43 and the emergency jacking system 44 thereof through the setting and coordination of the crane under the bridge and the hoisting system 5 on the bridge. It is not restricted by the large clearance under the existing bridge or the narrow site, significantly reduces the construction difficulty of the temporary support system 4, and ensures the construction safety.

[0060] In summary, the construction method of the temporary support system when replacing piers of an existing bridge of the present invention can provide a stable and reliable temporary support system for replacing piers of an existing bridge, ensure the construction safety when replacing piers of an existing bridge, and reduce the construction difficulty of the temporary support system.

[0061] Finally, it should be noted that: the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0062] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A construction method for a temporary support system when replacing piers of an existing bridge, characterized in that: The following steps are involved: Construction site preparation: Harden and level the construction area near the original piers of the existing bridge; Temporary support foundation construction: construct foundation caps on the ground on both sides of the original bridge piers in the longitudinal direction, and embed multiple support seats in the top surface of the foundation caps; Installation of steel pipe brackets: A set of steel pipe brackets is respectively installed under the bridge spans on both sides of the original bridge piers in the longitudinal direction. Each set of the steel pipe brackets includes a front row of steel pipe brackets close to the original bridge piers and a rear row of steel pipe brackets far away from the original bridge piers. The front and rear rows of the steel pipe brackets are connected to each other and their bottoms are connected to the support seat. Installation of jacking system: A jacking system is installed on the top of each of the two front-row steel pipe racks. The top surfaces of the two jacking systems are respectively pressed against the bottom surfaces of the T-beams of the bridge spans above them, so as to be used for jacking the bridge spans, temporary support after jacking, and falling back after pier replacement; Installation of emergency top support system: one set of emergency top support system is installed on the top of each of the two rear steel pipe racks, and a safety gap is reserved between the top surfaces of the two sets of emergency top support systems and the bottom surfaces of the T-beams of the bridge spans above them.

2. The construction method of the temporary support system when replacing piers of an existing bridge according to claim 1 is characterized in that: The construction steps of the temporary support foundation include: first, measuring and placing the plane positions of multiple pile foundations on the ground on both sides of the original bridge pier in the longitudinal direction, and constructing the pile foundations; then excavating the foundation pit, erecting the pedestal formwork, tying the pedestal steel bars, and pouring the foundation pedestal. When pouring the foundation pedestal, multiple support seats are pre-buried in the top surface of the foundation pedestal; each support seat is evenly provided with multiple bolts, and the top ends of the bolts protrude from the top surface of the foundation pedestal.

3. The construction method of a temporary support system when replacing piers of an existing bridge according to claim 2 is characterized in that: The pile foundation is a rock-embedded pile, and the depth of the pile foundation embedded in the bedrock is not less than 3 times the pile diameter of the pile foundation.

4. The construction method of a temporary support system when replacing piers of an existing bridge according to claim 1 is characterized in that: Each row of the steel pipe racks includes a plurality of steel pipe columns arranged at intervals transversely; the jacking system includes a first crossbeam, a first cushion beam and a plurality of jacks; the first crossbeam is connected to the top surfaces of all the steel pipe columns of the front row of steel pipe racks; a plurality of jacks are transversely arranged on the top surface of the first crossbeam, wherein a jack is correspondingly provided under the web of each T-beam of the bridge span, and a further jack is provided in addition to the two outermost jacks; the first cushion beam is crimped onto the top surfaces of all the jacks; a plurality of first cushion blocks are transversely arranged on the top surface of the first cushion beam, and the first cushion blocks are used to be crimped onto the bottom surface of the T-beam of the bridge span above it.

5. The construction method of a temporary support system when replacing piers of an existing bridge according to claim 4 is characterized in that: A limit block is protruded on the top surface at both ends of each of the first cushion beams, and the two limit blocks are respectively abutted against the horseshoe outer side surfaces of the T-beams at both ends of the bridge span above the first cushion beam.

6. The construction method of a temporary support system when replacing piers of an existing bridge according to claim 4 is characterized in that: The emergency support system includes a second crossbeam, a second cushion beam and multiple support blocks. The second crossbeam is connected to the top surfaces of all steel pipe columns of the rear steel pipe rack. Multiple support blocks are transversely arranged on the top surface of the second crossbeam. The second cushion beam is crimped on the top surfaces of all support blocks. Multiple second cushion blocks are transversely arranged on the top surface of the second cushion beam. A safety gap is reserved between the second cushion block and the bottom surface of the T-beam of the bridge span above it.

7. The construction method of a temporary support system when replacing piers of an existing bridge according to claim 1 or 6, characterized in that: A safety gap of 15 mm to 20 mm is reserved between the top surface of each emergency support system and the bottom surface of the T-beam of the bridge span above it.

8. The construction method of a temporary support system when replacing piers of an existing bridge according to claim 6 is characterized in that: Each of the steel pipe columns comprises a plurality of vertically connected steel pipe segments; parallel joints and diagonal bracing members are connected between the steel pipe segments adjacent to each other in the transverse direction and in the longitudinal direction of the front and rear rows of steel pipe racks.

9. The construction method of a temporary support system when replacing piers of an existing bridge according to claim 8, characterized in that: When installing the steel pipe support, the jacking system and the emergency jacking system, the following steps are also included: A crane is set up near the original bridge pier under the bridge, and the steel pipe column is installed in sections by using the crane. After the installation of the steel pipe sections at the same height is completed, the flat joints and diagonal braces between the adjacent steel pipe sections in the horizontal direction and the vertical direction are immediately installed until the installation of the steel pipe bracket within the crane hoisting height range is completed; A hoisting system is arranged on the bridge span, and the hoisting system includes a traveling frame and a hoisting frame; the traveling frame spans across the existing bridge deck and can move back and forth in the longitudinal direction, and two hoisting winches are arranged transversely on the traveling frame; the hoisting frame is arranged transversely below the bridge span, and its two transverse ends are respectively connected to the two hoisting winches by lifting ropes, and an electric gantry vehicle that can move back and forth transversely along the hoisting frame is connected below the hoisting frame; the remaining steel pipe segments are installed by cooperating with the crane under the bridge and the hoisting system on the bridge, thereby completing the installation of the steel pipe bracket that exceeds the crane hoisting height range, and then the first crossbeam, the first cushion beam, the second crossbeam and the second cushion beam on the steel pipe bracket are installed.

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