Reaction device for vertical uplift static load test of cast-in-place concrete pile

Abstract

The present invention provides a reaction force device for a vertical pull-out static load test of a concrete bored pile, comprising a chassis, a steel partition, a steel anchor, a top plate, fine-rolled threaded steel, and a fine-rolled connector; the chassis comprises two parallel chassis cross beams and two chassis connecting beams fixed vertically into a square; the steel anchor is used to lock the reserved steel bars on the top of the bored pile one by one on the top surface of the adjacent steel partitions; the top plate comprises two top plate cross beams and two top plate connecting beams fixed vertically into a square, a number of top plate steel partitions, and a top plate reaction beam, the two ends of the several top plate steel partitions are respectively fixed under the two cross beams of the top plate, and the reaction beam is vertically fixed to the lower end of the middle part of the several steel partitions of the top plate; the chassis and the top plate are connected by fine-rolled threaded steel, and the fine-rolled connector is provided at both ends of the fine-rolled threaded steel. This device adopts a detachable assembly connection and is provided with lifting ears for easy lifting and transportation; it is quick to assemble and disassemble at the construction site test site, and no welding is required throughout the process, which can greatly improve the detection efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of engineering test and detection devices, in particular to a reaction force device for a vertical pull-out static load test of a concrete cast-in-place pile. Background Art

[0002] As urban high-rise buildings have grown taller and deeper in recent years, it has become very common to design basements with 1-3 floors. In order to resist the buoyancy of groundwater, the use of pull-out piles under the basement floor has become increasingly widespread.

[0003] At present, when domestic testing units conduct vertical pull-out static load tests on cast-in-place concrete piles, the reaction devices mostly use the reaction-reinforced steel pier welding method: a reaction main beam is erected above the piers on both sides of the pull-out test pile, a jack is placed in the middle of the beam top, and the reaction-reinforced steel pier is placed on the jack. Before the test, several extended steel bars of about 3m in length (with the same diameter as the longitudinal bars of the pile body) are cut, one end of the extended steel bar is overlapped and welded to each steel bar at the top of the pile, and the other end is welded one by one to the outer side of the steel pier above the jack. After the test, the two ends of the extended steel bar are burned and cut from the side of the steel pier and the top of the pile one by one to remove them. When the next pile is tested, the above steps are repeated.

[0004] This test method has two obvious disadvantages: First, due to the obstruction of the reaction beam above the pile top, there are 2-4 reserved steel bars at the lower end of the main beam, which cannot be extended and welded to the side of the reaction steel pier above the beam top. The longitudinal reinforcement of the cast-in-place pile cannot fully exert its pull-out force, especially when the design reinforcement reserve is limited. It cannot meet the test specification requirement of a maximum load of 2 times the design characteristic value of the pull-out force. Second, this method requires the construction unit to cooperate with welding, which consumes a lot of manpower and material resources, wasting time and materials. In addition, due to welding quality problems, individual steel bars often become unwelded during the test loading process, resulting in test failure. The test must be restarted after repair welding. The welding slag is difficult to remove after cutting, and the installation and disassembly preparation time is too long. The test efficiency is very low, which is often criticized by the client and the construction party.

[0005] Now some testing units have made some improvements to the above test methods:

[0006] One method involves using several parallel, evenly spaced steel partitions fixed to a short reaction beam. These are placed on jacks instead of reaction-ribbed steel piers, and steel anchors are used to lock the extended steel bars to the top of the steel partitions. While this method effectively reduces the welding workload at the top of the connecting bars, welding is still required to connect the pile top bars to the extended bars. Furthermore, the 2-4 reserved steel bars under the main beam cannot be extended due to obstruction by the main beam, and the longitudinal reinforcement of the cast-in-place piles still cannot fully exert its pull-out resistance.

[0007] Another method is to place a horizontal beam parallel to each of the two piers on the pile side, and place four jacks of the same type at equidistant ends of the two beams. Hoist two main beams across the two sides of the test pile and place them on the four jacks respectively. Surround the extended steel bars at the top of the pile in the middle, and then hoist several steel partitions through the gaps between the extended steel bars. The ends of the steel partitions are placed on the two main beams respectively, and use several steel anchors to lock each extended steel bar one by one on the top surface of each steel partition. The four jacks work in parallel and synchronously to apply static pull-out load to the test pile. Although this method effectively solves the problem that the 2-4 steel bars under the beam cannot be connected to bear the force in the above two methods, it still takes a long time to weld the connection between the pile top steel bar and the extended steel bar, and the test requires more equipment resources. In addition to adding a main beam, the stability of the four jacks working in parallel and synchronously will also decrease accordingly. If a problem occurs with one of the jacks during the test, the test will be terminated. Summary of the Invention

[0008] In view of the shortcomings of the above-mentioned traditional pull-out test technology, the purpose of the present invention is to provide a reaction force device for vertical pull-out static load test of concrete bored piles, which is easy to lift and transport, does not require welding throughout the process, and can be quickly assembled and disassembled at the construction site test site. It can not only ensure that the reserved steel bars on the pile top are fully stressed, but also reduce equipment requirements, shorten the test installation preparation time, and greatly improve the efficiency of the detection work.

[0009] In order to solve the problems of traditional test technology, the present invention adopts the following technical solutions:

[0010] The present invention provides a reaction force device for a vertical pull-out static load test of a concrete bored pile, comprising a chassis, a steel partition, a steel anchor, a top plate, fine-rolled threaded steel bars, and a fine-rolled connector; the chassis and the top plate are fixedly connected by the fine-rolled threaded steel bars and the fine-rolled connector;

[0011] The chassis includes two chassis cross beams and two chassis connecting beams, which are fixedly connected to form a square frame. Adjustment screws are provided at the four corners of the chassis cross beams to adjust the level of the chassis. The bottom end of the adjustment screw is integrally provided with a round pedestal seat, and the round pedestal seat is provided with a hexagonal nut.

[0012] Several of the steel partitions are hoisted in parallel through the reserved steel bar gaps on the top of the cast-in-place piles, and their two ends are respectively placed on the two crossbeams of the chassis;

[0013] The steel bar anchor is used to lock the reserved steel bars at the top of the cast-in-place piles one by one on the top surface of the adjacent steel partitions;

[0014] The top plate includes two top plate cross beams and two top plate connecting beams, a plurality of top plate steel partitions and a top plate reaction beam. The ends of the cross beams and the connecting beams are fixedly connected to form a square frame with the same size as the bottom plate. The ends of the plurality of top plate steel partitions are fixedly arranged at equal distances below the top plate cross beams. The top plate reaction main beam is fixed in the middle of the bottom surface of each steel partition and is perpendicular to the steel partition.

[0015] The chassis crossbeam and the top plate crossbeam are provided with slots for the finished rolled threaded steel bars to pass through, and the two ends of the plurality of finished rolled threaded steel bars pass through the slots of the chassis and top plate crossbeams respectively;

[0016] The chassis and top plate are passed through the slots of the top plate and chassis crossbeams by a number of the said fine-rolled threaded steel bars, and are evenly and symmetrically arranged vertically between the gaps of the chassis and top plate steel partitions. The two ends of the fine-rolled threaded steel bars are respectively tightened and fixed on the outer pads of the slots with fine-rolled connectors.

[0017] Preferably, a fixing nut is provided on the adjusting screw and the fixing nut is located at the lower end of the chassis crossbeam, and a pin hole is provided on the upper portion of the adjusting screw.

[0018] Preferably, the chassis steel partition includes an edge steel partition and a middle steel partition, and a pin is provided at the bottom of each end of the edge steel partition and the middle steel partition, and a lifting ear is provided at the top of each end; a triangular support plate is provided at each end of the edge steel partition.

[0019] The beneficial effects of the present invention are that the top and bottom plates are connected by a detachable assembly and equipped with lifting lugs, making them easy to lift and transport. This eliminates the need for welding and allows for quick assembly and disassembly at the construction site. This ensures that the reserved reinforcement at the pile top is fully stressed, reduces equipment requirements, shortens test installation preparation time, and significantly improves testing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A schematic structural diagram of a reaction force device for a vertical static load test of a bored concrete pile provided by an embodiment of the present invention;

[0022] Figure 2 Schematic diagram of the chassis structure;

[0023] Figure 3 Schematic diagram of the structure of the top plate;

[0024] Figure 4 It is a structural diagram of the edge steel partition;

[0025] Figure 5 It is a structural diagram of the middle steel partition;

[0026] Figure 6It is a structural diagram of the finish-rolled rebar;

[0027] Figure 7 Schematic diagram of the structure of the adjusting screw;

[0028] Figure 8 A partial view of the reaction force device for a vertical static load test of a cast-in-place concrete pile in use provided by an embodiment of the present invention;

[0029] Figure 9 It is a structural diagram of a steel bar lock;

[0030] Figure 10 A view of the use status of the reaction force device for the vertical pull-out static load test of cast-in-place concrete piles provided in an embodiment of the present invention.

[0031] Explanation of the accompanying numbers: 1-chassis, 2-chassis steel partition, 3-top plate, 4-fine-rolled threaded steel, 5-fine-rolled connector, 6-chassis crossbeam, 7-chassis connecting beam, 8-adjusting screw, 9-round base, 10-top plate connecting beam, 11-top plate crossbeam, 12-top plate steel partition, 13-top plate reaction beam, 14-fixing nut, 15-edge steel partition, 16-middle steel partition, 17-pin, 18-lifting ear, 19-triangular support plate, 20-pin hole, 21-pile top, 22-steel bar lock, 23-reaction main beam, 24-jack, 25-reserved steel bar at the top of the pile. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 efforts are within the scope of protection of the present invention.

[0033] like Figures 1 to 10 As shown, the reaction force device for the vertical pullout static load test of the concrete bored pile includes a base plate 1, a steel partition plate 2, a top plate 3, a finely rolled threaded steel bar 4, and a finely rolled connector 5; the base plate 1 and the top plate 3 are connected by the finely rolled threaded steel bar 4, and the finely rolled connector 5 is provided at both ends of the finely rolled threaded steel bar 4;

[0034] The chassis 1 includes two parallel chassis crossbeams 6 and two chassis connecting beams 7 fixed between the chassis crossbeams 6. Adjustment screws 8 are provided at both ends of the chassis crossbeams 6. The bottom ends of the adjustment screws 8 are integrally provided with a round table seat 9. A plurality of steel partitions 2 are arranged in parallel and their ends are mounted on the chassis crossbeams 6.

[0035] The top plate 3 includes two top plate connecting beams 10, two top plate cross beams 11, a plurality of top plate steel partitions 12 and a top plate reaction beam 13. The two top plate cross beams 11 and the top plate connecting beams 10 are welded into a square frame. The two ends of the top plate steel partitions 12 are fixed to the bottom of the top plate cross beams 11. The top plate reaction main beam 13 is fixed to the bottom end of the middle part of the top plate steel partition 12 and is perpendicular to the steel partition 12.

[0036] The two ends of the finished rolled threaded steel bar 4 pass through the chassis cross beam 6 and the top plate cross beam 11 respectively. The chassis cross beam 6 and the top plate cross beam 11 are provided with slots for the finished rolled threaded steel bar to pass through.

[0037] Preferably, a fixing nut 14 is provided on the adjusting screw 8 and the fixing nut 14 is located at the lower end of the chassis crossbeam 6 , and a pin hole 20 is provided on the upper portion of the adjusting screw.

[0038] Preferably, the chassis steel partition 2 includes an edge steel partition 15 and a middle steel partition 16. A pin 17 is provided at the bottom of each end of the edge steel partition 15 and the middle steel partition 16, and a lifting ear 18 is provided at the top of each end; a triangular support plate 19 is provided at each end of the edge steel partition 15.

[0039] The method of using the device is as follows: first, hoist the chassis 1 and place it around the pile top 21, adjust the center of the chassis 1 to coincide with the center of the pile top 21, then adjust the adjusting bolts 8 until the chassis 1 is horizontal, hoist several chassis steel partitions 2 parallel and symmetrically through the gaps between the reserved steel bars at the pile top, use the steel bar lock 22 to lock the reserved steel bars 25 at the top of the steel partitions one by one, then hoist the reaction main beam 23 and the jack 24, and then hoist the top plate 3 onto the jack 24, with the projection of the top plate crossbeam coinciding with the chassis crossbeam, finally use high-quality rolled threaded steel bars to vertically penetrate the corresponding slots of the top plate 3 and the chassis 1 respectively, and use high-quality rolled connectors 5 at both ends of the high-quality rolled threaded steel bars 4 to fix the top plate 3 and the chassis 1 into a whole, and complete the installation by rotating and adjusting the high-quality rolled connectors 5 at both ends of the high-quality rolled threaded steel bars so that the top plate 3 and the chassis 1 are fixed parallel to each other.

[0040] The full welding-free process first solves the time-consuming and labor-intensive problem of welding extended steel bars before the test and cutting the steel bars to clean the welding slag after the test. Secondly, it solves the problem that the 2-4 steel bars under the beam of the traditional detection method are blocked by the main beam and cannot be connected to bear the force. It also solves the problem of the large number of jacks required and the stability of the test system in the improved detection method mentioned in the background technology.

[0041] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. The reaction force device for vertical pull-out static load test of concrete bored piles is characterized by: It includes a chassis, a steel partition, a steel anchor, a top plate, a precision-rolled threaded steel bar and a precision-rolled connector; the chassis and the top plate are connected by the precision-rolled threaded steel bar, and the precision-rolled connector is provided at both ends of the precision-rolled threaded steel bar; The chassis includes two chassis cross beams and two chassis connecting beams, which are fixedly connected to form a square frame. Adjustment screws are provided at the four corners of the chassis to adjust the level of the chassis. The bottom end of the adjustment screw is integrally provided with a round pedestal seat, and the round pedestal seat is provided with a hexagonal nut. Several chassis steel partitions are hoisted in parallel on the top of the cast-in-place piles to reserve gaps between the steel bars, and their two ends are placed on the two crossbeams of the chassis respectively; The steel bar anchor is used to lock the reserved steel bars at the top of the cast-in-place piles one by one on the top surface of the adjacent chassis steel partitions; The top plate includes two top plate cross beams and two top plate connecting beams, a plurality of top plate steel partitions and a top plate reaction beam. The ends of the two top plate cross beams and the two top plate connecting beams are fixedly connected to form a square frame with the same size as the bottom plate. The ends of the plurality of top plate steel partitions are fixedly arranged at equal distances below the top plate cross beams. The top plate reaction beam is fixed to the bottom end of the middle of the plurality of top plate steel partitions and is perpendicular to the top plate steel partitions. The chassis crossbeam and the top plate crossbeam are provided with slots for the finished rolled threaded steel bars to pass through, and the two ends of the plurality of finished rolled threaded steel bars pass through the slots of the chassis and top plate crossbeams respectively, and the finished rolled threaded steel bars are evenly and vertically arranged between the chassis and top plate steel partitions respectively; The chassis and top plate are respectively tightened and fixed on the outer side pads of the chassis and top plate cross beam slots by a number of the said fine-rolled threaded steel bars and fine-rolled connectors; the said chassis steel partition includes two side steel partitions and a number of middle steel partitions, and the bottom of both ends of the said side steel partition and the middle steel partition are each provided with a pin for positioning, and a lifting ear is respectively provided at the top of both ends for easy lifting; a triangular support plate is respectively provided at both ends of the said side steel partition to play a supporting and stabilizing role.

2. The reaction force device for vertical pull-out static load test of cast-in-place concrete piles according to claim 1, characterized in that: A fixing nut is provided on the adjusting screw and is located at the lower end of the chassis connecting beam. A pin hole is provided on the upper portion of the adjusting screw.

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