A Multi-Vibration Table-Based Vehicle-Mounted Deformation Difference Simulation Test Device and Method for Bridge Splice Joints

Abstract

The present invention relates to the technical field of concrete model test devices, and in particular to a bridge joint vehicle-mounted deformation difference simulation test device and method based on multiple vibration tables. In the simulation method of the present invention, a simulation test of the wet joint construction of the new and old bridges is carried out by combining a prefabricated test beam and a plurality of vibration table groups; at the same time, in the plurality of vibration tables, a plurality of first vibration tables respectively use time-history curve data collected at different positions of the old bridge for vibration simulation; this method is closer to the actual vibration mode of the old bridge, and at the same time, the influence of simultaneous vibration of different displacements on the deformation difference of the post-casting strip is taken into account, so that the entire simulation process is closer to the actual process, and the final data is more meaningful for reference, and the improvement strategy for the wet joint construction of the new and old bridges made for the cracks at the position of the post-casting strip and the maximum bearing capacity data is more effective.

Description

Technical Field

[0001] The invention relates to the technical field of concrete model test devices, and in particular to a bridge joint vehicle-mounted deformation difference simulation test device and method based on multiple vibration tables. Background Art

[0002] With the continuous development of my country's economy, the original road and bridge traffic conditions can no longer meet the increasing traffic demand, and the widening and splicing projects of old bridges are gradually increasing. In order to reduce the impact of such projects on people's livelihood and economy during the construction process, the rapid widening construction process without interrupting traffic is the first choice and also an important challenge. Due to the non-interruption of traffic, the old bridge section will be stimulated to vibrate and deform under the load of traffic, while the new bridge section will not vibrate during the construction process. Therefore, the deformation difference caused by this traffic load will have a certain impact on the quality of the splicing joint. Researchers at home and abroad have done some numerical calculations and experimental simulations on such engineering phenomena, and through simulation tests, a series of parameter studies have been conducted on the influence of vehicle-borne vibration and the performance of concrete in the splicing joint.

[0003] At present, there are no corresponding test standards and regulated test devices. In previous studies, in order to simulate the traffic load on the old bridge, two sections of precast beams or slabs are generally prefabricated as the new and old bridge sections. The middle post-cast section is fixed to the prefabricated section. The vibration simulation is performed by installing an actuator on the top of the test component and a spring on the bottom. There are also vibration simulations through a vibration table. In the existing test schemes and devices, the device reciprocates by controlling force loading or displacement loading to simulate the vibration state of the bridge. Generally, loading simulation is performed in the form of fixed displacement, which is inconsistent with the actual situation. In actual situations, the vibration law of the bridge is not stable, and the test generally does not consider the influence of the vibration condition on the deformation difference due to the change of the longitudinal position of the bridge. The existing specimen device cannot well restore the vibration condition of the real bridge, and the obtained simulation data is inconsistent with the test data during the actual construction process, and cannot be used as a theoretical basis for the wet joint construction plan of the real bridge. Summary of the invention

[0004] The purpose of the present invention is to provide a bridge joint vehicle-borne deformation difference simulation test device and a corresponding test method that are closer to actual engineering conditions in response to the technical defects existing in previous experimental research processes, so as to solve the problem that the simulation test of vehicle-borne deformation difference in existing bridge splicing projects is not close enough to the actual situation, and the technical defect that in existing tests, the study of plate-shaped specimens and the influence of the longitudinal force of the bridge on the deformation difference are ignored, resulting in the simulation data being not of reference value.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A bridge joint vehicle-mounted deformation difference simulation test device based on multiple vibration tables comprises a detachably connected prefabricated test beam and a plurality of groups of vibration tables; the prefabricated test beam is divided into a first precast section, a postcast section and a second precast section in sequence along its width direction; each group of vibration tables comprises a first vibration table and a second vibration table, respectively, the first vibration table is arranged below the first precast section, and the second vibration table is arranged below the second precast section; two adjacent groups of vibration tables are arranged at intervals.

[0007] The present invention summarizes the crack size, deformation, bearing capacity and other properties of bridge joints in a large number of old bridge widening and splicing projects, proposes a study on the influence of vehicle-borne vibration on the performance of concrete in joints, and simulates the influence of different construction processes on the deformation of concrete in joints under traffic loads of old bridges, thereby evaluating the construction effect of new bridges and making more reasonable suggestions for splicing projects.

[0008] The present invention provides an improved vehicle-mounted deformation difference simulation test device, which is based on the vibration process of an actual bridge. The vibration law is not stable, and the change in vibration due to position change along the length of the bridge is not taken into account, and the influence on the deformation difference is further produced; the vibration simulation scheme of the bridge is independently carried out at different displacement points and used as the theoretical basis for the construction of traffic bridges. This method does not accurately guide the actual bridge joint engineering. The technical scheme of the present invention proposes a method of combining multiple groups of vibration tables with prefabricated test beams and slabs; and inputs corresponding time-history curve data to multiple vibration tables on one side of the simulated old bridge; to realize the study of the influence of the increase of the elastic modulus of the post-casting section on the deformation difference; the vibration at different positions on a certain length of the old bridge is analyzed as a whole to study the deformation difference of the joint, so that the test data is closer to the actual change law of the bridge, the data is more representative, and it is more instructive for the adjustment of the construction plan of the joint.

[0009] As a preferred technical solution of the present invention, the post-casting section is provided with a support formwork, and a plurality of strain gauges for signal collection are pasted on the exposed steel bars in the support formwork. The other end of the strain gauge is connected to the signal collection device.

[0010] As a preferred technical solution of the present invention, the supporting formwork includes a base plate and relatively arranged side plates; it also includes contour reinforcement strips, the contour reinforcement strips include first reinforcement strips and second reinforcement strips, the first reinforcement strips and the second reinforcement strips are vertically and horizontally laid on the base plate, the first reinforcement strip is a long side strip, the second reinforcement strip is a short side strip, and the second reinforcement strip is detachably connected to the first reinforcement strip; it also includes third reinforcement strips, the third reinforcement strips are arranged on the side plates, the third reinforcement strips are spaced apart along the width direction of the side plates, and the third reinforcement strips are detachably connected to the first reinforcement strips.

[0011] As a preferred technical solution of the present invention, the prefabricated test beam and slab are prepared according to the following method:

[0012] Step S1: constructing a beam-slab mold, wherein the beam-slab mold is a rectangular shell, and three rectangular sub-areas are divided in the same direction in the rectangular shell, and the three rectangular sub-areas are respectively a first pre-casting area, a post-casting area, and a second pre-casting area, and the three rectangular sub-areas are independent of each other, and the three rectangular sub-areas respectively correspond to the first pre-casting section, the post-casting section, and the second pre-casting section of the test beam-slab, and the post-casting area and the pre-casting areas adjacent to both ends are provided with partition plates, and the template corresponding to each rectangular sub-area is detachably connected to the template of the adjacent area; the templates corresponding to adjacent rectangular sub-areas are detachably connected; a steel cage is provided in the beam-slab mold, and the size of the steel cage is adapted to the rectangular shell;

[0013] Step S2: pouring concrete in the first and second pre-casting areas, and after the concrete in the first and second pre-casting areas is finally set, removing the formwork corresponding to the first and second pre-casting areas; thus, the prefabricated test beam and slab are obtained.

[0014] As a preferred technical solution of the present invention, in the side panel, the two panels corresponding to the post-casting area are respectively made of transparent materials. The template of transparent material can enable the experimenter to clearly observe the changing state of concrete in the post-casting area during the simulation test of the post-casting area.

[0015] As a preferred technical solution of the present invention, a simulation method of a bridge joint vehicle-mounted deformation difference simulation test device based on a multi-vibration table comprises the following steps:

[0016] Step 1: Collect data on the old bridge to be widened;

[0017] Step 2: Adjust the simulation test device; the first pre-cast section is used to simulate the old bridge side, the second pre-cast section is used to simulate the new bridge side; the post-cast section is used to simulate the wet joint; pour concrete into the post-cast section, and after the concrete pouring is completed, immediately turn on the first vibration table to collect the steel bar strain gauge reading; when the concrete in the post-cast section reaches final setting, turn off the first vibration table and unload the test beam and slab;

[0018] Step 3: demoulding the post-cast section of the test beam and slab, and then observing the crack position, shape and length of the test beam and slab, and measuring the crack width with a crack width gauge.

[0019] In the above simulation method, a combination of prefabricated test beams and multiple groups of vibration tables was used to conduct a simulation test on the construction of wet joints between the new and old bridges. At the same time, in the multiple groups of vibration tables, multiple first vibration tables respectively collected time-history curve data at different positions of the old bridge for vibration simulation. This method is closer to the actual vibration mode of the old bridge. At the same time, the influence of simultaneous vibrations of different displacements on the deformation difference of the post-casting section is taken into account, making the entire simulation process closer to the real process. The final data is more meaningful for reference, and the improvement strategy for the construction of wet joints between the new and old bridges based on the cracks at the post-casting section and the maximum bearing capacity data is more effective.

[0020] As a preferred embodiment of the present invention, in step 1, a plurality of laser displacement meters are installed under the target old bridge to be widened to collect bridge vibration curves under different vehicle conditions; the laser displacement meters are installed in a certain span of the target bridge, and a plurality of the laser displacement meters are arranged at intervals to record the vibration time history curve of 1±0.2h as the original input data information of the simulation test.

[0021] After analysis, it is found that the amplitude is the largest at the mid-span and two adjacent eighth points. Further preferably, during the simulation test, the arrangement of the vibration table is set corresponding to the interval with the largest amplitude during the data collection process.

[0022] As a preferred embodiment of the present invention, the beam and slab formwork is a rectangular shell, which is respectively formed by splicing a bottom plate, a top plate, a first side plate and a second side plate. The first side plate is a side perpendicular to the post-casting area, and the second side plate is a side parallel to the post-casting area. The first side plate on each side includes three independently arranged plates according to the division of the first casting area and the post-casting area, and the three independent plates correspond to two first casting areas and one post-casting area respectively; the bottom plate also includes three independently arranged plates, and the three independently arranged plates correspond to the first casting area and the post-casting area one by one respectively; the second side plates arranged relatively to each other correspond to the side faces of the first casting area.

[0023] As a preferred embodiment of the present invention, the prefabricated test beam and slab is 10-15m long and 1.5-1.7m wide, and the width of the post-cast section of the test beam and slab is 500mm.

[0024] As a preferred solution of the present invention, the distance between adjacent first vibration tables is 5m.

[0025] As a preferred embodiment of the present invention, in step 2, in the simulation test device, a plurality of laser displacement meters are arranged below the post-casting section to monitor the deformation difference data of the post-casting section during the operation of the first vibration table.

[0026] As a preferred embodiment of the present invention, step 4 is also included: carrying out a bearing capacity test on the test beam and slab, loading until the specimen is destroyed, observing the cracking and destruction process of the side, top and bottom surfaces of the post-cast section of the test beam and slab, and recording data on the cracking conditions of specific cracks through a comprehensive crack tester.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0028] The simulation test of the wet joint construction of the new and old bridges was carried out by combining prefabricated test beams and multiple groups of vibration tables. At the same time, among the multiple groups of vibration tables, multiple first vibration tables respectively collected time-history curve data at different positions of the old bridge for vibration simulation. This method is closer to the actual vibration mode of the old bridge. At the same time, the influence of simultaneous vibration of different displacements on the deformation difference of the post-casting section is taken into account, making the entire simulation process closer to the real process. The final data is more meaningful for reference, and the improvement strategy for the wet joint construction of the new and old bridges made according to the cracks at the post-casting section and the maximum bearing capacity data is more effective. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a three-dimensional schematic diagram of the arrangement of the test piece and the vibration table of the simulation test of the present invention;

[0030] Figure 2 It is a front view cross-sectional structural schematic diagram of the arrangement of the test piece and the vibration table of the simulation test of the present invention;

[0031] Figure 3 It is a front cross-sectional view of a bridge joint vehicle-mounted deformation difference simulation test specimen (beam-slab mold) of the present invention;

[0032] Figure 4 It is a top view of a cross-sectional view of a bridge joint vehicle-mounted deformation difference simulation test specimen (beam-slab mold) of the present invention;

[0033] Figure 5 It is a side cross-sectional schematic diagram of a bridge joint vehicle-mounted deformation difference simulation test specimen (beam and slab) of the present invention;

[0034] Figure 6 It is a schematic diagram of real bridge data collection of the present invention;

[0035] Figure 7 It is a top view of the three-dimensional structure of the prefabricated beam slab in the present invention;

[0036] Figure 8 It is a bottom-up three-dimensional structural schematic diagram of the prefabricated beam slab in the present invention;

[0037] Fig. 9 It is a comparison diagram of the deformation difference along the long side of the test piece of the present invention and the test piece of the prior art;

[0038] Icons: 1-first vibration table; 2-second vibration table; 3-first pre-cast section; 4-post-cast section, 5-second pre-cast section, 61-bottom plate, 62-first side plate, 63-second side plate, 8-first steel bar, 9-stirrups, 10-laser displacement meter, 11 splicing side, 13-third reinforcement bar, 15-first reinforcement bar, 16-second reinforcement bar. DETAILED DESCRIPTION

[0039] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] Example 1

[0042] A bridge joint deformation difference simulation test device based on multiple vibration tables, comprising a detachably connected prefabricated test beam and three groups of vibration tables; the prefabricated test beam is divided into a first precast section 3, a postcast section 4 and a second precast section 5 in sequence along its width direction; each group of vibration tables comprises a first vibration table 1 and a second vibration table 2, respectively, the first vibration table 1 is arranged below the first precast section 3, and the second vibration table 2 is arranged below the second precast section 5; two adjacent groups of vibration tables are arranged at intervals.

[0043] Specifically, the post-casting section 4 is provided with a support formwork, and a plurality of strain gauges for signal collection are pasted on the exposed steel bars in the support formwork. The other end of the strain gauge is connected to the signal collection device.

[0044] The supporting formwork includes a base plate 61 and oppositely arranged side plates; it also includes contour reinforcement strips, the contour reinforcement strips include a first reinforcement strip 15 and a second reinforcement strip 16, the first reinforcement strip 15 and the second reinforcement strip 16 are laid vertically and horizontally on the base plate 61, the first reinforcement strip 15 is a long side strip, the second reinforcement strip 16 is a short side strip, and the second reinforcement strip 16 is detachably connected to the first reinforcement strip 15; it also includes a third reinforcement strip 13, the third reinforcement strip 13 is arranged on the side plates, the third reinforcement strip 13 is spaced apart along the width direction of the side plates, and the third reinforcement strip 13 is detachably connected to the first reinforcement strip 15.

[0045] Specifically, Figure 3-4 , Figure 7-8 The beam and slab mold is shown; the prefabricated test beam and slab are prepared according to the following method:

[0046] Step S1: constructing a beam-slab mold, the beam-slab mold is a rectangular shell, three rectangular sub-areas are divided in the same direction in the rectangular shell, the three rectangular sub-areas are the first pre-casting area, the post-casting area and the second pre-casting area in turn, the three rectangular sub-areas are independent of each other, the three rectangular sub-areas correspond to the first pre-casting section 3, the post-casting section 4 and the second pre-casting section 5 of the test beam-slab respectively, the post-casting area and the pre-casting areas adjacent to both ends are provided with partition plates, the template corresponding to each rectangular sub-area is detachably connected to the template of the adjacent area; the templates corresponding to adjacent rectangular sub-areas are detachably connected; a steel cage is provided in the beam-slab mold, and the size of the steel cage is adapted to the rectangular shell;

[0047] The rectangular shell is respectively formed by splicing a bottom plate 61, a first side plate 62 and a second side plate 63. The first side plate 62 is a side perpendicular to the post-casting area, and the second side plate 63 is a side parallel to the post-casting area. The first side plate 62 on each side includes three independently arranged plates according to the division of the first casting area and the post-casting area, and the three independent plates correspond to two first casting areas and one post-casting area respectively; the bottom plate 61 also includes three independently arranged plates, and the three independently arranged plates correspond to the first casting area and the post-casting area respectively; the second side plates 63 arranged opposite to each other all correspond to the side faces of the first casting area.

[0048] Step S2: pouring concrete in the first and second pre-casting areas, and after the concrete in the first and second pre-casting areas is finally set, removing the formwork corresponding to the first and second pre-casting areas; thus, the prefabricated test beam and slab are obtained.

[0049] Example 2

[0050] This embodiment takes a bridge to be widened as a research object, and carries out a detailed practice process of a bridge joint vehicle-borne deformation difference simulation method based on a multi-vibration table; specifically, the following steps are included:

[0051] Step 1: Collect data on the target old bridge to be widened; install several laser displacement meters 10 under the target bridge to collect bridge vibration curves under different vehicle conditions; specifically, select a section of the bridge span and set multiple laser displacement meters 10 at intervals, and set different speed limits or retain different numbers of lanes for different road condition variables. During the morning and evening peak hours, record the vibration time history curve for about 1 hour; after data analysis, it is found that the amplitude is the largest at the mid-span of the bridge span and at two adjacent eighth points. During the simulation test, the layout of the vibration table is set corresponding to the interval with the largest amplitude; the specific data collection method is as follows: Figure 6 As shown, 11 is the side of the old bridge to be spliced, and a laser displacement meter 10 is arranged below.

[0052] Step 2: Adjust the simulation test device; the first pre-cast section is used to simulate the old bridge side, the second pre-cast section is used to simulate the new bridge side; the post-cast section is used to simulate the wet joint; pour concrete into the post-cast section, and after the concrete pouring is completed, immediately turn on the first vibration table to collect the steel bar strain gauge reading; when the concrete in the post-cast section reaches final setting, turn off the first vibration table and unload the test beam and slab;

[0053] Specifically, Figure 4-5 As shown, the steel cage includes a first steel bar 8 and a stirrup 9. The steel bars in the post-casting area are polished, and a strain gauge is pasted on the polished steel bars; the other end of the strain gauge is connected to the signal acquisition device; the steel bars in the middle post-casting area are polished, and the selected positions are the interface of the first cast and the post-cast concrete, the quarter point and the half point. The polished surface is parallel to the plane on the specimen and faces directly upward. The width is slightly larger than the width of the steel bar strain gauge, which is about 5 to 8 mm, and the length is controlled at about 1.5 cm, providing enough pasting space for the strain gauge and the fixed terminal. At room temperature, 502 water is applied to the back of the strain gauge and the back of the fixed terminal, and it can be pasted successfully by pressing on the polished plane for about 20 seconds. After the 502 glue is completely solidified, the strain gauge and the terminal are applied with 705 glue to protect them from moisture erosion in the concrete. The general concrete strain gauge is connected with a 15-30 cm wire, which is not long enough compared with the depth of the specimen, so a 30 cm long wire needs to be connected in advance. Connect the steel bar strain gauges through the acquisition box and additional wires, and use computer software to record and analyze the stress and strain data collected during vibration;

[0054] Step 3: demoulding the post-cast section of the test beam and slab, and then observing the crack position, shape and length of the test beam and slab, and measuring the crack width with a crack width gauge.

[0055] In this embodiment, the time curves of these three points in the simulation specimen are selected for input. The length of the specimen must be greater than the distance between two adjacent eighth points (10 meters), the total length is 15 meters, the width of the middle post-casting section is 50 cm, the width of the first-casting sections at both ends is 60 cm, the total horizontal length is 1.7 meters, and the height is 250 mm.

[0056] In the first side plate 62, the two plates corresponding to the post-casting area are made of transparent materials. The template of transparent material can enable the experimenter to clearly observe the changing state of concrete in the post-casting area during the simulation test of the post-casting area. On the bottom plate 61 and the top surface located in the post-casting area, at least three first reinforcing strips 15 are arranged along the length direction thereof, and a plurality of second reinforcing strips 16 are arranged at intervals perpendicular to the direction of the first reinforcing strips 15. On the first side plate 61 located in the post-casting section 4, at least two third reinforcing strips 13 are arranged along the width direction thereof, and the positions of the third reinforcing strips 13 correspond to the positions of the first reinforcing strips 15 one by one. The first reinforcing strips 15, the second reinforcing strips 16 and the third reinforcing strips 13 are fixed to each other by screws.

[0057] Three sets of vibration tables are set at intervals along the length of the precast beams and slabs. Figure 1-2 As shown, each group of vibration tables includes a first vibration table 1 and a second vibration table 2, wherein the first vibration table 1 is arranged at the bottom of the first precasting area 3 of the precast beam slab, and the second vibration table 2 is arranged at the bottom of the second precasting area 5 of the precast beam slab; a plurality of laser displacement meters 10 are arranged at intervals at the bottom of the post-casting area of ​​the precast beam slab; the first vibration table 1 is fixed to the first precasting section 3 by screws; the second vibration table 2 is fixed to the second precasting section 5 by screws;

[0058] Pour concrete into the post-casting section 4. After the concrete pouring is completed, all the first vibration tables 1 are immediately turned on. The first vibration tables 1 collect corresponding strain data through the signal acquisition device and deformation data of different positions in the post-casting area through the laser displacement meter 10. For the first vibration tables 1 on the same side, the vibration time-history curves of the corresponding positions are input respectively. Multiple test pieces can be synchronously set to input vibration time-history curves at different speeds respectively. The speed limit in this embodiment is 60km / h (in addition, 80km / h and 100km / h precast beam and slab simulation tests can be set). When the concrete in the post-casting area reaches final setting, all the first vibration tables 1 are turned off. During vibration, the post-casting section 4 is poured, and the vibration time is 24 hours. The vertical displacement changes of the vibrating side and the non-vibrating side at the vibration table position are monitored through multiple laser displacement meters 10 set on both sides of the post-casting section. At the same time, the cracking of the concrete can be observed through the transparent acrylic side panels. In this embodiment, a total of six laser displacement meters 10 are set at the bottom of the post-casting area of ​​each beam and slab, three close to the splicing side of the old bridge and three close to the splicing side of the new bridge;

[0059] The concrete was cured for 28 days. After the formwork was removed, the specimen was placed on a loading table for moment loading until the specimen was damaged. The loading curve was recorded and compared with the data collected by the steel bar strain gauge during the period. After the specimen was damaged, the crack condition was observed with a comprehensive crack tester, and the effect of vibration on the mechanical properties of concrete under different traffic conditions was analyzed and compared.

[0060] The above-mentioned embodiment 1 is a simulation test of different precast beams under different speed limits; this embodiment can also carry out a simulation test of vibration time history curve data under different numbers of traffic lanes. Specifically, the number of lanes is one lane and two lanes, one lane is open for the lane close to the splicing side, and the other two lanes are closed; the two lanes are the adjacent first lane and second lane close to the splicing side, which are open, and the third lane is closed.

[0061] Comparative Example 1

[0062] This comparative example uses a bridge to be widened as the same as Example 2 as the research object, and carries out a detailed practice process of the vehicle-borne deformation difference simulation method of the bridge joint based on a single vibration table; specifically, it includes the following steps:

[0063] Step 1: Collect data on the target old bridge to be widened; install several laser displacement meters under the target bridge to collect bridge vibration curves under different vehicle conditions; specifically, select a section of the bridge span and set multiple laser displacement meters 10 at intervals, and set different speed limits or reserve different numbers of lanes for the bridge to perform different road condition variables, and record the vibration time history curve for about 1 hour during the morning and evening peak hours; after data analysis, it is found that the amplitude is the largest at the mid-span of the bridge span. During the simulation test, the vibration at the mid-span position is taken for vibration simulation; the specific data collection method is as follows: Figure 6 As shown, 11 is the side of the old bridge to be spliced, and a laser displacement meter 10 is arranged below.

[0064] Step 2: Adjust the simulation test device; the first pre-cast section is used to simulate the old bridge side, the second pre-cast section is used to simulate the new bridge side; the post-cast section is used to simulate the wet joint; pour concrete into the post-cast section, and after the concrete pouring is completed, immediately turn on the first vibration table to collect the steel bar strain gauge reading; when the concrete in the post-cast section reaches final setting, turn off the first vibration table and unload the test beam and slab;

[0065] Specifically, Figure 4-5As shown, the steel cage includes a first steel bar 8 and a stirrup 9. The steel bars in the post-casting area are polished, and a strain gauge is pasted on the polished steel bars; the other end of the strain gauge is connected to the signal acquisition device; the steel bars in the middle post-casting area are polished, and the selected positions are the interface of the first cast and the post-cast concrete, the quarter point and the half point. The polished surface is parallel to the plane on the specimen and faces directly upward. The width is slightly larger than the width of the steel bar strain gauge, which is about 5 to 8 mm, and the length is controlled at about 1.5 cm, providing enough pasting space for the strain gauge and the fixed terminal. At room temperature, 502 water is applied to the back of the strain gauge and the back of the fixed terminal, and it can be pasted successfully by pressing on the polished plane for about 20 seconds. After the 502 glue is completely solidified, the strain gauge and the terminal are applied with 705 glue to protect them from moisture erosion in the concrete. The general concrete strain gauge is connected with a 15-30 cm wire, which is not long enough compared with the depth of the specimen, so a 30 cm long wire needs to be connected in advance. Connect the steel bar strain gauges through the acquisition box and additional wires, and use computer software to record and analyze the stress and strain data collected during vibration;

[0066] Step 3: demoulding the post-cast section of the test beam and slab, and then observing the crack position, shape and length of the test beam and slab, and measuring the crack width with a crack width gauge.

[0067] In this embodiment, only the time history curve with the maximum amplitude is selected for input in the simulation specimen, and only one large vibration table is used to provide the same vibration power in the longitudinal direction. The specimen is 6 meters long, the width of the middle post-casting section is 50 cm, the width of the pre-casting sections at both ends is 60 cm, the total horizontal length is 1.7 meters, and the height is 250 mm.

[0068] like Fig. 9 The deflection distribution diagrams obtained by performing the experiments according to Example 2 and Comparative Example 1 are shown. It can be clearly seen from the figure that in Example 2, the relative deformation difference in the middle of the component is larger, while the relative deformation difference at both ends is smaller. In Comparative Example 1, the relative deformation difference of the entire component is consistent. In comparison, the simulation method in Example 2 can more effectively simulate the actual vehicle-bridge coupling vibration state, thereby obtaining more accurate experimental conclusions.

[0069] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A simulation method for a bridge joint vehicle-mounted deformation difference simulation test device based on a multi-vibration table, characterized in that: The steps include: Step 1: Data collection is performed on the target old bridge to be widened; a plurality of laser displacement meters are installed under the target old bridge to be widened to collect bridge vibration curves under different vehicle conditions; the laser displacement meters are installed in a certain span of the target bridge, and a plurality of the laser displacement meters are arranged at intervals to record the vibration time history curve of 1±0.2h as the original input data information of the simulation test; Step 2: Adjust the simulation test device; the simulation test device comprises a detachably connected precast test beam and a plurality of vibration tables; the precast test beam is divided into a first precast section (3), a postcast section (4) and a second precast section (5) in sequence along its width direction; each group of vibration tables comprises a first vibration table (1) and a second vibration table (2), the first vibration table (1) being arranged below the first precast section (3), and the second vibration table (2) being arranged below the second precast section (5); two adjacent groups of vibration tables are arranged at intervals along the length direction of the precast test beam; in the simulation test device, a plurality of laser displacement meters are arranged below the postcast section (4) to monitor the deformation difference data of the position of the postcast section (4) during the operation of the first vibration table (1); The first precast section (3) is used to simulate the old bridge side, and the second precast section (5) is used to simulate the new bridge side; the postcast section (4) is used to simulate the wet joint; concrete is poured into the postcast section (4), and after the concrete pouring is completed, the first vibration table (1) is immediately turned on to collect the steel bar strain gauge reading; when the concrete in the postcast section (4) reaches final setting, the first vibration table (1) is turned off, and the test beam and slab are unloaded; the precast test beam and slab is 10-15m long, and the postcast section (4) of the test beam and slab is 500-550mm wide; the distance between adjacent first vibration tables (1) is 5-5.5m, and the first vibration table (1) arranged at the end is 2.2-2.5m away from the end of the precast test beam and slab; Step 3: demoulding the post-casting section (4) of the test beam and slab, and then observing the position, shape and length of the cracks in the test beam and slab, and measuring the crack width with a crack width meter.

2. The simulation method according to claim 1, characterized in that: The method also includes step 4: conducting a bearing capacity test on the test beam and slab, loading until the test piece is destroyed, observing the cracking and destruction process of the side, top and bottom surfaces of the post-cast section (4) of the test beam and slab, and recording data on the cracking conditions of specific cracks using a comprehensive crack tester.

3. The simulation method according to claim 1, characterized in that: The post-casting section (4) is provided with a support formwork, and a plurality of strain gauges for signal collection are pasted to the exposed steel bars in the support formwork.

4. The simulation method according to claim 3, characterized in that: The supporting formwork comprises a bottom plate (61) and side plates (62) arranged opposite to each other; the bottom plate (61) and the side plates (62) are detachably connected; The invention comprises a contour reinforcement strip, wherein the contour reinforcement strip comprises a first reinforcement strip (15) and a second reinforcement strip (16), wherein the first reinforcement strip (15) and the second reinforcement strip (16) are laid vertically and horizontally on the bottom plate (61), wherein the first reinforcement strip (15) is a long side strip, and the second reinforcement strip (16) is a short side strip, and the second reinforcement strip (16) is detachably connected to the first reinforcement strip (15); It also comprises a third reinforcement strip (13), the third reinforcement strip (13) being arranged on the side panel, the third reinforcement strip (13) being arranged at intervals along the width direction of the side panel, and the third reinforcement strip (13) being detachably connected to the first reinforcement strip (15).

5. The simulation method according to claim 4, characterized in that: The side plate (62) is made of a transparent material.

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