A kind of long-term loading and measurement synchronous test device of steel pipe concrete reinforced hybrid structure

Abstract

The application provides a kind of steel pipe concrete reinforced mixed structure long-term loading and measurement synchronous test device, including loading assembly, load measurement assembly, deformation measurement assembly, steel pipe concrete reinforced mixed structure.Loading assembly is mainly composed of loading plate, loading rod, nut, pre-tightening disc spring;Load measurement assembly is composed of force sensor;Deformation measurement assembly is mainly composed of measurement device;Steel pipe concrete reinforced mixed structure is a force structure.Through the invention of steel pipe concrete reinforced mixed structure long-term loading and measurement synchronous test device, the phased loading of internal steel pipe concrete and external reinforced concrete and the synchronous measurement of long-term internal force and deformation are realized, the key problem that internal force and deformation of internal steel pipe concrete and external reinforced concrete under phased construction condition cannot be accurately analyzed is solved, and reliable test results for further research on internal force redistribution law and deformation development law of such structure under long-term load are provided.

Description

Technical Field

[0001] This invention belongs to the field of structural engineering technology, specifically relating to a test device for simultaneous long-term loading and measurement of steel-concrete composite stiffened structures. Background Technology

[0002] Steel-concrete composite reinforced structures, as a novel type of engineering structure, possess numerous advantages such as high load-bearing capacity, good seismic performance, structural stability, and good corrosion resistance, and are widely used in bridge construction. However, under long-term loads, concrete, due to its inherent material properties, undergoes significant creep. For long-span arch bridges, concrete creep leads to a redistribution of internal forces, exerting a nonlinear influence on the structure's stress and deformation, which can pose safety hazards to the project.

[0003] For reinforced concrete-steel tubular structures, commonly used loading measurement devices, such as the loading device used by Wang Qingli et al. in "Device and Method for Studying the Performance of Reinforced Concrete-Steel Tube Axially Compressed Members under Load and Corrosion", can only apply a one-time load to the entire cross-section of the reinforced concrete-steel tubular structure. They cannot perform phased loading on the core reinforced concrete-steel tubular part and the outer reinforced concrete part of the reinforced concrete-steel tubular structure, which limits the study of the mechanical properties of the structure under phased construction conditions.

[0004] This invention provides a test device for long-term loading and simultaneous measurement of reinforced concrete-steel tube structures. This device enables phased loading of the internal steel tube concrete portion and the external reinforced concrete portion, and allows for long-term synchronous measurement of the internal forces and deformations of each part of the structure. It solves the problem of existing loading devices being unable to accurately distinguish the internal forces and deformations of the internal concrete and external reinforced concrete portions under phased construction conditions. This provides technical support for further research on the redistribution of internal forces and the development of deformation in such structures under long-term loads. Summary of the Invention

[0005] This invention proposes a test device for simultaneous long-term loading and measurement of reinforced concrete tubular (PCTB) structures. Previous loading devices often treated the PCTB structure as a single unit, rarely considering the phased construction and load-bearing characteristics of this type of structure, and failing to perform phased loading and measurement of the internal PCTB portion and the entire structure. This invention aims to solve the problems in existing loading and measurement technologies for PCTB structures by loading the internal PCTB portion and the entire structure in two phases, separately measuring the stress state of the internal PCTB portion and the outer reinforced concrete portion, performing independent stress analysis, and obtaining the creep characteristics of each concrete component, providing a basis for scientific calculation and analysis in practical engineering.

[0006] The technical solution of this invention is as follows:

[0007] A test device for long-term loading and measurement of a steel-concrete composite reinforced structure includes a loading component 10, a load measurement component 20, a deformation measurement component 30, and a steel-concrete composite reinforced structure 40.

[0008] The loading assembly 10 includes an upper loading plate 101, a lower loading plate 102, a spoke sensor pad 103, a spoke sensor nesting plate 104, a lower loading rod 105, an upper loading rod 106, a lower nut 107, a middle nut 108, an upper nut 109, a lower disc spring 110, a middle disc spring 111, and an upper disc spring 112. The upper loading rod 106 passes through the upper loading plate 101, and its end is fixed to the upper loading plate 101 by the cooperation of the upper nut 109 and the upper disc spring 112. The lower loading rod 105 passes through the spoke sensor nesting plate 104 and the lower loading plate 102 in sequence, and its end is fixed to the upper loading plate 101 by the cooperation of the lower nut 107 and the upper disc spring 112. The lower disc spring 110 is fixed to the lower loading plate 102, and the lower part is fixed to the spoke sensor nesting plate 104 by the middle nut 108 and the middle disc spring 111. The spoke sensor nesting plate 104 has a central hole, and one end of the spoke sensor pad 103 extends into the central hole of the spoke sensor nesting plate 104. A certain gap is left between the inner wall of the central hole of the spoke sensor nesting plate 104 and the outer wall of the spoke sensor pad 103, and the end of the spoke sensor nesting plate 104 and the surface of the spoke sensor pad 103 are on the same plane. The other end of the spoke sensor pad 103 is located on the lower loading plate 102.

[0009] At least four upper loading rods 106, four lower loading rods 105, four upper nuts 109, four lower nuts 107, four upper disc springs 112, and four lower disc springs 110, together with the upper loading plate 101, the spoke sensor pad 103, and the lower loading plate 102, form the internal steel-concrete composite loading structure of the steel-concrete composite stiffened hybrid structure 40; at least four upper loading rods 106, four lower loading rods 105, four upper nuts 109, four middle nuts 108, four upper disc springs 112, and four middle disc springs 111, together with the upper loading plate 101 and the spoke sensor nesting plate 104, form the external reinforced concrete loading structure of the steel-concrete composite stiffened hybrid structure 40; wherein, the upper loading rods 106, lower loading rods 105, upper nuts 109, upper disc springs 112, and upper loading plate 101 are shared parts with the internal steel-concrete composite loading structure of the steel-concrete composite stiffened hybrid structure 40;

[0010] The load measurement assembly 20 includes a tension sensor 21 and a spoke-type pressure sensor 22. The tension sensor 21 is connected to the lower loading rod 105 and the upper loading rod 106 at both ends, respectively, and is used to measure the load of the steel-concrete composite stiffened structure 40. The spoke-type pressure sensor 22 is installed on the spoke sensor pad 103 and is used to measure the load of the steel-concrete composite structure.

[0011] The deformation measurement assembly 30 includes a displacement gauge 31, a lower displacement gauge support 32, an upper displacement gauge support 33, a wire 34, and multiple strain gauges; at least two displacement gauges 31 and five strain gauges together form the deformation measurement system of the steel-concrete composite reinforced structure 40; the displacement gauge 31 is connected between the upper loading plate 101 and the lower loading plate 104 through the upper displacement gauge support 33 and the lower displacement gauge support 32, and the strain gauges are bonded to the interior and surface of the steel-concrete composite reinforced structure 40;

[0012] The steel-concrete composite reinforced structure 40 includes a steel pipe 41, concrete inside the steel pipe 42, concrete outside the steel pipe 43, longitudinal reinforcement 44, and stirrups 45. It serves as the loading and measurement object of the test device and is geometrically aligned and installed in the structural frame of the loading component 10. The steel pipe 41 and the concrete inside the steel pipe 42 constitute the steel-concrete composite structure, while the concrete outside the steel pipe 43, longitudinal reinforcement 44, and stirrups 45 constitute the outer reinforced concrete structure.

[0013] Furthermore, the cross-section of the spoke sensor pad 103 has the same shape and area as the cross-section of the steel-concrete composite pipe.

[0014] Furthermore, the spoke sensor pad 103 is provided with a threaded post and is connected to the threaded hole of the spoke-type pressure sensor 22 in the load measurement assembly 20.

[0015] Furthermore, the height of the spoke sensor pad 103 is adjusted by the lower nut 107 and the lower loading plate 102, so that the spoke sensor nesting plate 104 and the spoke sensor pad 103 remain on the same plane throughout the loading process.

[0016] Furthermore, during the pouring of the steel-concrete composite reinforced structure 40, the cross-section of the steel pipe 41 and the shape of the concrete 43 outside the steel pipe are not limited.

[0017] Furthermore, the strain gauges include a concrete strain gauge 35, a steel pipe transverse strain gauge 36, a steel pipe longitudinal strain gauge 37, a longitudinal reinforcement strain gauge 38, and a stirrup strain gauge 39.

[0018] A method for installing a test device that simultaneously performs long-term loading and measurement of a steel-concrete composite reinforced structure, the specific steps of which are as follows:

[0019] Step 1: As Figure 5 -① Weld steel pipe 41 at the geometric center of upper loading plate 101;

[0020] Step Two: As Figure 5 -② After welding, pour concrete 42 into the steel pipe from the other end of the steel pipe 41;

[0021] Step 3: As Figure 5 -③ Install the four sets of upper disc springs 112, upper nuts 109, and upper loading rods 106 sequentially to the openings at the four corners of the upper loading plate 101;

[0022] Step Four: As Figure 5 -④, connect one end of the tension sensor 21 to the other end of the upper loading rod 106, and connect the lower loading rod 105 to the other end of the tension sensor 21;

[0023] Step 5: As Figure 5 -⑤, attach the spoke sensor pad 103 to the other end of the steel pipe 41 and the concrete 42 inside the steel pipe, and put the spoke sensor nesting plate 104 onto the lower loading rod 105.

[0024] Step Six: As Figure 5 -⑥, install the middle disc spring 111 and the middle nut 108 on the lower loading rod 105 in sequence on the outside of the spoke sensor nesting plate 104, and firmly connect the spoke pressure sensor 22 to the spoke sensor pad 103.

[0025] Step Seven: As Figure 5 -⑦ Install the lower loading plate 102 onto the end of the lower loading rod 105, and install the lower disc spring 110 and the lower nut 107 on the outside of the lower loading plate 102 in sequence; flip the entire device so that the lower loading plate 102 is at the bottom and the upper loading plate 101 is at the top; attach the steel pipe transverse strain gauge 36 and the steel pipe longitudinal strain gauge 37 to the middle of the steel pipe 41, and fill the gap between the spoke sensor pad 103 and the spoke sensor nesting plate 104 with expanding foam 50;

[0026] Step 8: As Figure 5 -⑦ By adjusting the four middle nuts 108 and the lower nuts 107, the spoke sensor nesting plate 104 and the lower loading plate 102 are ensured to be horizontal, thereby ensuring that the bottom surface of the spoke pressure sensor 22 and the spoke sensor pad 103 are horizontal, so that the steel pipe concrete and the surrounding reinforced concrete are on the same plane; the constant axial load is applied by tightening the four upper nuts 109 diagonally in sequence to ensure that the loads of the four tension sensors 21 are the same, and the loading is stopped when the load value of the spoke pressure sensor 22 reaches the design load; during the long-term load holding process, the internal force of the steel pipe concrete is continuously measured by the spoke pressure sensor 22. When the internal force decreases due to concrete creep, the four upper nuts 109 are tightened in time to supplement the load;

[0027] Step Nine: As Figure 5 -⑧, fix the two ends of the longitudinal rib 44 to the upper loading plate 101 and the spoke sensor nesting plate 104 respectively along the direction of the steel pipe 41, and tie the stirrups 45 around the longitudinal rib 44.

[0028] Step 10: As Figure 5 -⑨, longitudinal reinforcement strain gauges 38 and stirrup strain gauges 39 are attached to the corresponding positions of longitudinal reinforcement 44 and stirrup 45 to measure the strain of the reinforcement; then, concrete 43 is poured around the steel pipe to form a steel-concrete reinforced hybrid structure 40. The displacement gauge 31 is installed between the upper loading plate 101 and the spoke sensor nesting plate 104 through the lower support 32, the upper support 33, and the wire 34 to measure the axial compression deformation of the steel-concrete reinforced hybrid structure 40; thus forming a test device for long-term loading and measurement of the steel-concrete reinforced hybrid structure.

[0029] Step 11: As Figure 5 -⑨ By adjusting the four middle nuts 108, the upper surface of the spoke sensor nesting plate 104 is made flush with the lower end surface of the concrete 42 inside the steel pipe. Loading is carried out by tightening the four upper nuts 109 diagonally in sequence to ensure that the load on the four tension sensors 21 is the same. Loading is stopped when the sum of the load values ​​of the four tension sensors 21 reaches the design load. During long-term load holding, if the internal force decreases due to concrete creep, the four upper nuts 109 are tightened in time to supplement the load.

[0030] The beneficial effects of this invention are as follows: It provides a method for manufacturing and installing a test device for long-term loading and measurement of a steel-concrete composite reinforced structure. By reasonably arranging the loading and measurement components, it is possible to apply loads to the steel-concrete composite part and the entire steel-concrete composite reinforced structure separately, and to independently measure the load and deformation of the steel-concrete composite part and the entire steel-concrete composite reinforced structure. It is possible to effectively analyze the load and deformation of the steel-concrete composite reinforced structure 40. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the loading assembly of the steel-concrete composite reinforced hybrid structure provided by the present invention;

[0032] Figure 2 This is a schematic diagram of the assembly of the load measurement component for the steel-concrete composite reinforced structure provided by the present invention.

[0033] Figure 3(a) is a schematic diagram of the assembly of the deformation measurement component of the steel-concrete composite stiffened hybrid structure provided by the present invention;

[0034] Figure 3(b) is a schematic diagram of the deformation measurement component of the steel-concrete composite stiffened structure provided by the present invention located inside the concrete outside the steel tube.

[0035] Figure 4 This is a schematic diagram of the steel-concrete composite reinforced structure component provided by the present invention;

[0036] Figure 5 This is a schematic diagram of the installation process of the test device provided by the present invention in the embodiment;

[0037] Figure 5 -① is a schematic diagram of the welding of steel pipes in the installation process of the test device provided by the present invention in the embodiment;

[0038] Figure 5 -② is a schematic diagram of the concrete pouring process inside the steel pipe during the installation process of the test device provided by the present invention in the embodiment;

[0039] Figure 5 -③ is a schematic diagram of the installation of the loading plate in the installation process of the test device provided by the present invention in the embodiment;

[0040] Figure 5 -④ is a schematic diagram of the installation of the tensile sensor in the installation process of the test device provided by the present invention in the embodiment;

[0041] Figure 5 -⑤ is a schematic diagram of the installation process of the wheel spoke sensor pad and wheel spoke sensor nesting plate in the installation process of the test device provided by the present invention in the embodiment;

[0042] Figure 5 -⑥ is a schematic diagram of the installation of the spoke-type pressure sensor in the installation process of the test device provided by the present invention in the embodiment;

[0043] Figure 5 -⑦ is a schematic diagram of the installation of the lower loading plate and the loading of the steel-concrete composite section in the installation process of the test device provided by the present invention in the embodiment;

[0044] Figure 5 -⑧ is a schematic diagram of the installation of the steel reinforcement cage in the installation process of the test device provided by the present invention in the embodiment;

[0045] Figure 5 -⑨ is a schematic diagram of the overall loading of the steel pipe concrete outside the steel pipe and the steel pipe concrete stiffening hybrid structure during the installation process of the test device provided by the present invention in the embodiment.

[0046] Figure 6 This is a graph showing the result data obtained using the experimental apparatus provided by the present invention in the embodiments;

[0047] Figure 6-(a) is a strain development data graph obtained by the test apparatus provided by the present invention in the embodiment;

[0048] Figure 6 -(b) is a diagram of the development data of internal forces of the structure obtained by the test device provided by the present invention in the embodiment.

[0049] In the diagram: 10 Loading assembly; 101 Upper loading plate; 102 Lower loading plate; 103 Wheel spoke sensor pad; 104 Wheel spoke sensor nesting plate; 105 Lower loading rod; 106 Upper loading rod; 107 Lower nut; 108 Middle nut; 109 Upper nut; 110 Lower disc spring; 111 Middle disc spring; 112 Upper disc spring; 20 Load measurement assembly; 21 Tension sensor; 22 Wheel spoke type pressure sensor; 30 Deformation measurement assembly; 31 Displacement gauge; 32 Displacement gauge lower support; 33 Displacement gauge upper support; 34 Wire; 35 Concrete longitudinal strain gauge; 36 Steel pipe transverse strain gauge; 37 Steel pipe longitudinal strain gauge; 38 Longitudinal reinforcement strain gauge; 39 Stirrup strain gauge; 40 Steel pipe reinforced concrete hybrid structure; 41 Steel pipe; 42 Concrete inside steel pipe; 43 Concrete outside steel pipe; 44 Longitudinal reinforcement; 45 Stirrup; 50 Foam. Detailed Implementation

[0050] The technical solutions of the present invention will be further described below with reference to the accompanying drawings in the embodiments of the present invention. Taking a large-span arch bridge with a steel-concrete composite stiffened frame and reinforced concrete outer shell as an example, in order to study the influence of construction loads on the mechanical properties of the structure, it is necessary to use the device of the present invention to conduct phased long-term load tests on the steel-concrete composite stiffened hybrid structural members. The following description uses this example.

[0051] Example

[0052] (1) Example Description

[0053] like Figure 1 The loading assembly 10 is disassembled into several sub-loading plates, sub-loading rods, sub-loading nuts, and sub-preload disc springs, allowing for separate processing and transportation, thus improving work efficiency. The loading assembly 10 is designed and assembled according to the geometry and load-bearing capacity of the steel-concrete reinforced composite structure 40. In this embodiment, for example... Figure 4 As shown, the steel tube of the reinforced concrete-filled steel tube structure 40 is a circular steel tube with a diameter D of 89 mm and a thickness t of 4.5 mm. The outer concrete is square with a side length B of 222 mm. The member has a uniform cross-section along its length, with a length L of 666 mm. The member is equipped with 12 longitudinal reinforcement bars 44 with a diameter of 8 mm, and 14 stirrups 45 with a diameter of 6 mm are evenly arranged along the longitudinal reinforcement bars 44. The concrete cover thickness of the member is 10 mm. The bearing capacity N of the member is calculated based on the strength of the concrete 42 inside the steel tube and the concrete 43 outside the steel tube. uThe load is 2241 kN. In this example, the long-term load ratios applied to the steel-concrete composite reinforced structural member in the two stages are respectively (N...). L1 =0.15, N L2 =0.2.

[0054] (2) Design and fabrication of experimental apparatus

[0055] Based on this component, a test device for simultaneous long-term loading and measurement of reinforced concrete tubular structures is designed: For example... Figure 1 As shown, the upper loading plate 101, lower loading plate 102, and spoke sensor nesting plate 104 are all squares with a side length of 465mm. A 38mm diameter circular hole is opened at each of the four corners of the square, 60mm from the edge. The spoke sensor pad 103 corresponds to the steel-concrete section and has a diameter of 89mm. The diameter of the opening at the geometric center of the spoke sensor nesting plate 104 is 91mm. The distance between the inner wall of the central hole of the spoke sensor nesting plate 104 and the outer wall of the spoke sensor pad 103 is 0-2mm. The lower loading rod 105 and upper loading rod 106 are 36mm diameter screws. The loading rods and the inner edges of the four corner openings of the loading plates are... The distance between the edges is 0-2mm, and nuts and disc springs matching the loading screw are used; the thickness of the upper loading plate 101, lower loading plate 102, spoke sensor pad 103, and spoke sensor nesting plate 104 is 30mm; the gap between the spoke sensor nesting plate 104 and the spoke sensor pad 103 is filled with expanding foam 50 before pouring the steel pipe outer concrete 43; as shown in Figures 3(a) and 3(b), the steel skeleton of the steel pipe outer concrete 43 consists of 12 longitudinal bars 44 with a diameter of 8mm and 14 stirrups 45 with a diameter of 6mm. The longitudinal bars 44 are connected to the loading plate by welding, and the stirrups 45 are tied to the outside of the longitudinal bars 44 by tie wire. The test device is manufactured according to the manufacturing steps of the test device for long-term loading and measurement synchronization of steel pipe concrete reinforced hybrid structure proposed in this patent.

[0056] (3) Fabricating a steel-concrete composite reinforced structure in the experimental apparatus of the invention.

[0057] like Figure 5As shown, steel pipe 41 is welded to upper loading plate 101, and concrete 42 is poured into the steel pipe with the other end of steel pipe 41 open upwards to form a steel pipe concrete module. After curing, the steel pipe concrete part of the specimen is loaded by loading component 10. After a period of time, lower loading plate 102, spoke sensor pad 103, and spoke sensor nesting plate 104 are installed in the corresponding positions by nuts and bolts, and foaming adhesive 50 is filled between spoke sensor pad 103 and spoke sensor nesting plate 104 to form steel pipe outer concrete 43. Upper and lower template modules; connecting the longitudinal reinforcement 44 between the upper loading plate 101 and the spoke sensor nesting plate 104, and binding the stirrups 45 around the longitudinal reinforcement 44 to form the steel reinforcement skeleton of the steel pipe concrete 43; welding the customized side template of the steel pipe concrete 43 between the upper loading plate 101 and the spoke sensor nesting plate 104 to form the template of the steel pipe concrete; placing the entire loading device horizontally, with the opening of the steel template of the steel pipe concrete 43 facing upward, and pouring the steel pipe concrete 43 to form a steel pipe concrete reinforced hybrid structure 40.

[0058] The method for fabricating a steel-concrete composite reinforced structure 40 in the device of the present invention, as described above, solves the problem of the staged long-term pouring process of first pouring the concrete 42 inside the steel pipe and then pouring the concrete 43 outside the steel pipe under load, which is impossible to realize in scientific research. This makes scientific research more in line with actual engineering and makes the research results more realistic and accurate.

[0059] (4) Stage loading of steel-concrete composite reinforced structure based on the experimental device of the invention

[0060] The steel-concrete composite reinforced structure is subjected to 40-stage loading: The steel-concrete composite structure with the concrete inside the steel pipe 42 poured is installed into the test device provided by this invention for long-term loading and measurement of the steel-concrete composite reinforced structure; the transverse strain gauge 36 and longitudinal strain gauge 37 of the steel pipe are attached to the surface of the middle position of the steel pipe 41; the four middle nuts 108 are adjusted to the same horizontal plane to ensure that the spoke sensor nesting plate 104 is horizontal; the displacement gauge 31 is installed between the upper loading plate 101 and the spoke sensor nesting plate 104 through the lower displacement gauge support 32, the upper displacement gauge support 33, and the pull wire 34; the four lower nuts 107 are adjusted to the same horizontal plane to ensure that the lower loading plate 102 is horizontal, thereby ensuring that the bottom surface of the spoke pressure sensor 22 is horizontal and the spoke sensor pad 103 is horizontal, thus ensuring that the steel-concrete composite structure is subjected to axial load; the loads of the tension sensor 21 and the spoke pressure sensor 22 are zeroed in the unloaded state; Figure 5-⑦ Tighten the four upper nuts 109 diagonally in sequence to ensure that the load on the four tension sensors 21 is the same. Stop loading when the load value of the spoke pressure sensor 22 reaches the design load. This completes the process of applying load to the steel-concrete composite section separately.

[0061] Level the four central nuts 108 and adjust the height of the spoke sensor nesting plate 104 so that the upper surface of the spoke sensor nesting plate 104 is flush with the lower end surface of the concrete 42 inside the steel pipe; weld the longitudinal reinforcement 44 between the upper loading plate 101 and the spoke sensor nesting plate 104, tie the stirrups 45 around the longitudinal reinforcement 44 to form a reinforcing cage for the concrete 43 outside the steel pipe, and fix the formwork for the concrete 43 outside the steel pipe at the designed position outside the reinforcing cage, pour the concrete 43 outside the steel pipe and cure it; Figure 5 -⑨ Load the load by tightening the four upper nuts 109 diagonally in sequence to ensure that the load on the four tension sensors 21 is the same. Stop loading when the sum of the load values ​​of the four tension sensors 21 reaches the design load. This completes the process of applying load to the steel-concrete composite stiffened structure 40 as a whole.

[0062] The measured results of creep and load on the component under two-stage long-term loading in this example are shown in the figure below. t1 represents the first stage where a long-term load is applied only to the steel-concrete composite section, and t2 represents the second stage where a long-term load is applied to the entire steel-concrete composite reinforced structure 40 after the outer concrete of the steel tube is poured. The test results show that the device of this invention can collect the creep deformation of the structure throughout the entire stress process and can simultaneously and independently collect the internal forces of the steel-concrete composite section and the outer reinforced concrete section.

[0063] The staged loading method for the steel-concrete composite reinforced structure 40 introduced above is used to solve the scientific problem of not being able to accurately distinguish the internal forces of the internal steel-concrete composite part and the external reinforced concrete part. It provides reliable experimental results for further research on the redistribution law of internal forces and deformation development law of this type of structure under long-term load.

Claims

1. A test device for simultaneous long-term loading and measurement of a steel-concrete composite reinforced structure, characterized in that, The test apparatus includes a loading component (10), a load measuring component (20), a deformation measuring component (30), and a steel-concrete composite reinforced structure (40). The loading assembly (10) includes an upper loading plate (101), a lower loading plate (102), a spoke sensor pad (103), a spoke sensor nesting plate (104), a lower loading rod (105), an upper loading rod (106), a lower nut (107), a middle nut (108), an upper nut (109), a lower disc spring (110), a middle disc spring (111), and an upper disc spring (112). The upper loading rod (106) passes through the upper loading plate (101), and its end is fixed to the upper loading plate (101) by the cooperation of the upper nut (109) and the upper disc spring (112). The lower loading rod (105) passes through the spoke sensor nesting plate (104) and the lower loading plate (102) in sequence, and its end is fixed to the upper loading plate (101) by the cooperation of the lower nut (109) and the upper disc spring (112). The nut (107) and the lower disc spring (110) are fixed to the lower loading plate (102) in cooperation. The lower part is fixed to the spoke sensor nesting plate (104) in cooperation with the middle nut (108) and the middle disc spring (111). The spoke sensor nesting plate (104) has a central hole. One end of the spoke sensor pad (103) extends into the central hole of the spoke sensor nesting plate (104). There is a certain gap between the inner wall of the central hole of the spoke sensor nesting plate (104) and the outer wall of the spoke sensor pad (103). The end of the spoke sensor nesting plate (104) and the surface of the spoke sensor pad (103) are on the same plane. The other end of the spoke sensor pad (103) is located on the lower loading plate (102). At least four upper loading rods (106), four lower loading rods (105), four upper nuts (109), four lower nuts (107), four upper disc springs (112), and four lower disc springs (110), together with the upper loading plate (101), the spoke sensor pad (103), and the lower loading plate (102), form the steel-concrete composite reinforcement structure (40) internal steel-concrete composite loading structure; at least four upper loading rods (106), four lower loading rods (105), and four upper nuts (109) form the steel-concrete composite reinforcement structure (40). The central nut (108), four upper disc springs (112), four central disc springs (111), together with the upper loading plate (101) and the spoke sensor nesting plate (104), form the outer reinforced concrete loading structure of the steel-concrete composite reinforced structure (40); among them, the upper loading rod (106), the lower loading rod (105), the upper nut (109), the upper disc spring (112), and the upper loading plate (101) are common parts with the loading structure of the steel-concrete composite reinforced structure (40) inside the steel-concrete composite reinforced structure (40); The load measurement assembly (20) includes a tension sensor (21) and a spoke-type pressure sensor (22). The tension sensor (21) is connected to the lower loading rod (105) and the upper loading rod (106) at both ends, respectively, and is used to measure the load of the steel-concrete composite stiffened structure (40). The spoke-type pressure sensor (22) is installed on the spoke sensor pad (103) and is used to measure the load of the steel-concrete composite structure. The deformation measurement component (30) includes a displacement gauge (31), a lower displacement gauge support (32), an upper displacement gauge support (33), a wire (34), and multiple strain gauges; at least two displacement gauges (31) and five strain gauges together form the deformation measurement system of the steel-concrete composite reinforced structure (40); the displacement gauge (31) is connected between the upper loading plate (101) and the lower loading plate (102) through the upper displacement gauge support (33) and the lower displacement gauge support (32), and the strain gauges are bonded to the interior and surface of the steel-concrete composite reinforced structure (40); The steel-concrete composite reinforced structure (40) includes a steel pipe (41), concrete inside the steel pipe (42), concrete outside the steel pipe (43), longitudinal reinforcement (44), and stirrups (45), which are the loading and measurement objects of the test device and are geometrically aligned and installed in the structural frame of the loading component (10); wherein the steel pipe (41) and the concrete inside the steel pipe (42) constitute the steel-concrete composite structure, and the concrete outside the steel pipe (43), longitudinal reinforcement (44), and stirrups (45) constitute the outer reinforced concrete.

2. The experimental apparatus for simultaneous long-term loading and measurement of steel-concrete composite reinforced structures according to claim 1, characterized in that, The cross-section of the spoke sensor pad (103) has the same shape and area as the cross-section of the steel-concrete composite pipe.

3. The experimental apparatus for simultaneous long-term loading and measurement of steel-concrete composite reinforced structures according to claim 1, characterized in that, The spoke sensor pad (103) is provided with a threaded post and is connected to the threaded hole of the spoke pressure sensor (22) in the load measurement assembly (20).

4. The experimental apparatus for simultaneous long-term loading and measurement of steel-concrete composite reinforced structures according to claim 1, characterized in that, The height of the spoke sensor pad (103) is adjusted by the lower nut (107) and the lower loading plate (102) to ensure that the spoke sensor nesting plate (104) and the spoke sensor pad (103) remain on the same plane throughout the loading process.

5. The experimental apparatus for simultaneous long-term loading and measurement of steel-concrete composite reinforced structures according to claim 1, characterized in that, The strain gauges include a concrete longitudinal strain gauge (35), a steel pipe transverse strain gauge (36), a steel pipe longitudinal strain gauge (37), a longitudinal reinforcement strain gauge (38), and a stirrup strain gauge (39).

6. A method for installing a test device for simultaneous long-term loading and measurement of a steel-concrete composite reinforced structure, characterized in that, The specific steps are as follows: Step 1: Weld steel pipe (41) at the geometric center of the upper loading plate (101); Step 2: After welding, pour concrete (42) into the steel pipe from the other end of the steel pipe (41). Step 3: Install the four sets of upper disc springs (112), upper nuts (109), and upper loading rods (106) into the corresponding openings at the four corners of the upper loading plate (101) in sequence; Step 4: Connect one end of the tension sensor (21) to the other end of the upper loading rod (106), and connect the lower loading rod (105) to the other end of the tension sensor (21). Step 5: Attach the spoke sensor pad (103) to the other end of the steel pipe (41) and the concrete (42) inside the steel pipe, and put the spoke sensor nesting plate (104) onto the lower loading rod (105); Step 6: Install the middle disc spring (111) and the middle nut (108) on the lower loading rod (105) in sequence on the outside of the spoke sensor nesting plate (104), and firmly connect the spoke pressure sensor (22) to the spoke sensor pad (103); Step 7: Install the lower loading plate (102) onto the end of the lower loading rod (105), and install the lower disc spring (110) and lower nut (107) on the outside of the lower loading plate (102) in sequence; flip the entire device so that the lower loading plate (102) is at the bottom and the upper loading plate (101) is at the top; attach the steel pipe transverse strain gauge (36) and steel pipe longitudinal strain gauge (37) to the middle of the steel pipe (41), and fill the gap between the spoke sensor pad (103) and the spoke sensor nesting plate (104) with expanding foam (50). Step 8: By adjusting the four middle nuts (108) and the lower nuts (107), ensure that the spoke sensor nesting plate (104) and the lower loading plate (102) are horizontal, thereby ensuring that the bottom surface of the spoke pressure sensor (22) and the spoke sensor pad (103) are horizontal, so that the steel pipe concrete and the outer reinforced concrete are on the same plane; the axial load is constant and is applied by tightening the four upper nuts (109) diagonally in sequence to ensure that the loads of the four tension sensors (21) are the same. When the load value of the spoke pressure sensor (22) reaches the design load, the loading is stopped; during the long-term load holding process, the internal force of the steel pipe concrete is continuously measured by the spoke pressure sensor (22). When the internal force decreases due to concrete creep, the four upper nuts (109) are tightened in time to supplement the load; Step 9: Fix both ends of the longitudinal rib (44) along the direction of the steel pipe (41) to the upper loading plate (101) and the spoke sensor nesting plate (104) respectively, and tie the stirrups (45) around the longitudinal rib (44); Step 10: Attach longitudinal reinforcement strain gauges (38) and stirrup strain gauges (39) to the corresponding positions of longitudinal reinforcement (44) and stirrups (45) to measure the strain of the reinforcement; then pour concrete (43) around the steel pipe to form a steel-concrete reinforced hybrid structure (40). Install the displacement gauge (31) between the upper loading plate (101) and the spoke sensor nesting plate (104) through the lower support (32), upper support (33), and pull wire (34) of the displacement gauge to measure the axial compression deformation of the steel-concrete reinforced hybrid structure (40); form a test device for long-term loading and measurement of the steel-concrete reinforced hybrid structure. Step 11: Adjust the four middle nuts (108) to make the upper surface of the spoke sensor nesting plate (104) flush with the lower end of the concrete (42) inside the steel pipe. Load the load by tightening the four upper nuts (109) diagonally in sequence to ensure that the load on the four tension sensors (21) is the same. Stop loading when the sum of the load values ​​of the four tension sensors (21) reaches the design load. If the internal force decreases due to concrete creep during long-term load holding, tighten the four upper nuts (109) in time to supplement the load.

Images