A pseudo-dynamic test device and method for assembling a beam-slab-column joint of an underground station structure

Abstract

The application discloses an assembly underground station structure beam slab column joint pseudo-dynamic test device and method, belongs to the field of assembled underground structure seismic resistance technology, and comprises a test specimen model, a counterforce wall, a transverse actuating mechanism, a hinged support, a clamping support and a longitudinal actuating mechanism, the test specimen model is composed of multiple prefabricated components; the counterforce wall comprises vertically arranged counterforce wall vertical walls and horizontally arranged counterforce wall bases; the transverse actuating mechanism is fixedly arranged on the inner side of the counterforce wall vertical wall and connected with the top end of the prefabricated upper column, is used for transmitting reciprocating load to simulate transverse seismic action; the hinged support is fixedly connected on the counterforce wall base; the clamping support is fixedly connected with the test specimen model and is used for simulating earth pressure applied to the test specimen model on both sides of the station structure; the longitudinal actuating mechanism is fixedly connected on the counterforce frame, the longitudinal actuating mechanism acts on the top end of the prefabricated upper column and applies axial compression to simulate top earth pressure and road surface load. The application can intuitively simulate the seismic damage process and the form of the large underground structure joint.

Description

Technical Field

[0001] This invention relates to the field of seismic resistance technology for prefabricated underground structures, and in particular to a pseudo-dynamic test device and method for beam-slab-column joints of prefabricated underground station structures, used to simulate the dynamic response and failure mode of joints under seismic loading. Background Technology

[0002] Prefabricated buildings are characterized by high efficiency, environmental friendliness, and convenience. The construction method of joint assembly can greatly shorten the on-site construction period, and the modular design can effectively improve the reuse rate of formwork, resulting in high economic benefits. Prefabricated underground structures are gradually being promoted due to their high efficiency and environmental friendliness. Numerous prefabricated joint tests have shown that prefabricated structures can achieve seismic performance that is basically equivalent to cast-in-place structures through reasonable joint assembly design. However, the existing prefabricated joint test methods are mainly for above-ground structures and do not consider the stress characteristics of underground structures (such as earth pressure, truncation constraints, etc.).

[0003] Existing underground structural mechanics tests are usually model tests of the entire structure, including two model test methods: shaking table under normal gravity and centrifuge shaking table under hypergravity. The above two model test methods have the following two problems in actual operation: both require complex model test design of soil-underground structure interaction system, and have limitations such as the inability to unify the similarity ratio, difficulty in preparing model foundations and small model structure size. They cannot intuitively and realistically reproduce the failure process, collapse mode and other node damage evolution processes of underground structures. Summary of the Invention

[0004] Technical problem to be solved: In view of the fact that the existing node test methods in the background technology are mainly for above-ground structures and do not consider the stress characteristics of underground structures (such as earth pressure, truncation constraints, etc.), and that traditional shaking table tests have problems such as inconsistent similarity ratios and complex model preparation, this invention provides a pseudo-dynamic test device and method for assembling beam-slab-column joints of underground station structures, which can intuitively simulate the seismic failure process and morphology of large underground structure joints.

[0005] Technical solution: The present invention provides a pseudo-dynamic testing device for beam-slab-column joints of an assembled underground station structure, comprising: The specimen model consists of multiple precast components, including precast floor slabs, precast lower columns, precast longitudinal beams, and precast upper columns; The reaction wall includes a vertically arranged reaction wall vertical wall and a horizontally arranged reaction wall base at the bottom of the reaction wall vertical wall, wherein the reaction wall vertical wall and the reaction wall base are integrally formed; A lateral actuation mechanism is fixedly installed horizontally along the axial direction on the inner side of the reaction wall vertical wall and connected to the top of the prefabricated upper column. It is used to transmit reciprocating loads to simulate lateral seismic action. A hinged support, which is fixedly connected to the reaction wall base; A clamping bracket is fixedly connected to the specimen model and is used to simulate the soil pressure exerted on the specimen model by both sides of the station structure. A longitudinal actuation mechanism is fixedly connected to a reaction frame on the reaction wall base. The lower end of the longitudinal actuation mechanism acts on the top of the precast upper column and applies axial pressure to simulate the top soil pressure and road load.

[0006] Preferably, the lateral actuation mechanism includes a lateral actuation mechanism base that is axially and horizontally fixed inside the vertical wall of the reaction wall. A lateral servo actuator is hinged to the lateral actuation mechanism base. The power output end of the lateral servo actuator is connected to a ring clamp, which is correspondingly fitted onto the top of the precast upper column.

[0007] Preferably, the longitudinal actuation mechanism includes a longitudinal actuation mechanism base fixedly connected to the reaction frame, and a longitudinal servo actuator is provided at the lower end of the longitudinal actuation mechanism base. The power output end of the longitudinal servo actuator is connected to the top of the precast upper column.

[0008] Preferably, the top of the precast lower column has a pre-reserved extended longitudinal reinforcement bar, the extended length of which is not less than 0.9m; the bottom of the precast upper column has a built-in grouting sleeve, which is used to align and connect with the extended longitudinal reinforcement bar of the precast lower column.

[0009] Preferably, the precast longitudinal beam has a circular cavity isolated by a steel corrugated pipe in the center, and the circular cavity is used for the outward longitudinal reinforcement of the precast lower column to pass through.

[0010] Preferably, the top of the precast longitudinal beam is provided with multiple U-shaped lap bars along the beam body direction, and the precast floor slab is provided with connecting steel bars on the corresponding side of the precast longitudinal beam and is connected to the precast longitudinal beam through U-shaped lap bars. After the precast longitudinal beam and the precast floor slab are spliced ​​together, an open cavity is formed at the top for subsequent concrete pouring.

[0011] Preferably, the clamping bracket includes two I-beams and two struts respectively installed at both ends and sides of the precast floor slab; the lower end of the I-beam is provided with a sliding support fixedly connected to the reaction wall base, and the sliding support is used to limit the spatial height position of the precast floor slab.

[0012] This invention also discloses a pseudo-dynamic test method for beam-slab-column joints of an assembled underground station structure, which uses the aforementioned pseudo-dynamic test device and includes the following loading steps: Step 1: Install the hinged support and sliding support on the reaction wall base accordingly, and hoist the specimen model and fix it to the hinged support; Step 2: Install and fix the lateral actuation mechanism, longitudinal actuation mechanism, clamping bracket, and specimen model respectively; Step 3: Apply reciprocating loads to simulate earthquake action through the lateral actuation mechanism, adjust the axial pressure and strut preload through the longitudinal actuation mechanism, record the test data and analyze the node failure process.

[0013] Compared with the prior art, the present invention has at least the following outstanding advantages: 1. The pseudo-dynamic testing equipment and method of this invention simulates the earth pressure transmitted laterally from the station structure by fixing the clamping bracket to the specimen model. It simulates the earth pressure and road load transmitted from the upper part of the station structure by applying axial compression to the top of the precast upper column. It simulates the seismic response of the node under lateral seismic action by applying reciprocating load to the side of the top of the precast upper column. By simulating actual constraint conditions, it conforms to the stress characteristics of underground structures and improves the accuracy of test data. At the same time, the graded loading system can be compared with the seismic performance level classification of underground station structures based on inter-story drift angle (IDR). 2. The pseudo-dynamic test equipment and method of the present invention can avoid the defect that the similarity ratio of the soil-structure dynamic interaction system cannot be unified, and the key node is less affected by the size effect compared with the overall model test, making it easier to observe the structural damage evolution process. 3. A graded loading system is adopted, which is directly linked to the seismic performance level, to guide engineering practice. Attached Figure Description

[0014] Figure 1 This is a front view of the structure of the pseudo-dynamic experimental device of the present invention; Figure 2 for Figure 1 Top view of the structure of the simulated dynamic experimental device; Figure 3 This is a diagram illustrating the loading process of the method of the present invention; Figure 4 for Figure 1 Front view of the prototype model structure; Figure 5 for Figure 4 Schematic diagram of precast floor slab structure; Figure 6 for Figure 4 Schematic diagram of prefabricated lower column structure; Figure 7 for Figure 4 Schematic diagram of the precast longitudinal beam structure; Figure 8 for Figure 4 Schematic diagram of prefabricated upper column structure; Figure 9 for Figure 4 Assembly flowchart of pilot specimen model.

[0015] Reference numerals in the attached drawings: 1. Vertical wall of the reaction wall; 2. Base of the reaction wall; 3. Positioning slot; 4. Lateral actuation mechanism; 41. Base of the lateral actuation mechanism; 42. Lateral servo actuator; 5. First connecting bolt; 6. Fixing bolt of the hinge support; 7. Hinge support; 8. Specimen model; 81. Precast floor slab; 811. Connecting steel bar; 82. Precast lower column; 821. Longitudinal reinforcement; 83. Precast longitudinal beam; 831. Circular cavity; 832. U-shaped lap joint; 84. Precast upper column; 841. Grouting sleeve; 9. I-beam; 10. Support rod; 11. Sliding support; 12. Longitudinal actuation mechanism; 121. Base of the longitudinal actuation mechanism; 122. Longitudinal servo actuator; 13. Ring clamp; 14. Reaction frame. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the accompanying drawings. Figures 1-9 The technical solutions of the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0017] Example 1: As Figures 1-2 As shown, the present invention discloses a pseudo-dynamic test device for assembling beam-slab-column joints of an underground station structure. The pseudo-dynamic test device includes a specimen model 8, a reaction wall, a lateral actuation mechanism 4, a hinge support 7, a clamping bracket, and a longitudinal actuation mechanism 12.

[0018] like Figures 4-9 As shown, the specimen model 8 consists of multiple precast components, including a precast floor slab 81, a precast lower column 82, a precast longitudinal beam 83, and a precast upper column 84; the top of the precast lower column 82 has a pre-reserved extended longitudinal reinforcement 821, the extended length of which is not less than 0.9m; the bottom of the precast upper column 84 has a built-in grouting sleeve 841, which is used to align and connect with the extended longitudinal reinforcement 821 of the precast lower column 82; the precast longitudinal beam 83 has a circular cavity 831 isolated by a steel corrugated pipe in the center, through which the extended longitudinal reinforcement 821 of the precast lower column 82 passes. The top of the precast longitudinal beam 83 is provided with multiple U-shaped lap bars 832 along the beam body direction. The precast floor slab 81 includes two pieces arranged correspondingly on both sides of the precast longitudinal beam 83. The precast floor slab 81 and the precast longitudinal beam 83 are provided with connecting steel bars 811 on the corresponding side and are connected to the precast longitudinal beam 83 through U-shaped lap bars 832. After the precast longitudinal beam 83 and the precast floor slab 81 are spliced ​​together, an open cavity is formed at the top for subsequent concrete pouring.

[0019] like Figure 1As shown, the reaction wall includes a vertically arranged reaction wall 1 and a horizontally arranged reaction wall base 2 at the bottom of the reaction wall 1. The reaction wall 1 and the reaction wall base 2 are integrally formed. A set of positioning slots 3 are evenly opened on the reaction wall 1. The transverse actuation mechanism 4 is fixedly connected to the positioning slots 3 of the reaction wall 1 through the first connecting bolt 5.

[0020] like Figures 1-2 As shown, the lateral actuation mechanism 4 includes a lateral actuation mechanism base 41 that is axially and horizontally fixed inside the reaction wall vertical wall 1. A lateral servo actuator 42 is hinged on the lateral actuation mechanism base 41. The power output end of the lateral servo actuator 42 is connected to a ring clamp 13, which is correspondingly fitted on the top of the precast upper column 84. The lateral actuation mechanism 4 is used to transmit reciprocating loads to simulate lateral seismic action.

[0021] like Figure 1 As shown, the hinge support 7 is fixedly connected to the reaction wall base 2 by the hinge support fixing bolt 6, and the precast lower column 82 of the test specimen model 8 for assembling the beam-slab-column joint of the underground station structure is installed on the hinge support 7.

[0022] like Figures 1-2 As shown, the clamping bracket includes two I-beams 9 and two struts 10 respectively installed at both ends and sides of the precast floor slab 81; the lower end of the I-beams 9 is provided with a sliding support 11 fixedly connected to the reaction wall base 2, and the sliding support 11 is used to limit the spatial height position of the precast floor slab 81; the clamping bracket is fixedly connected to the specimen model 8 and is used to simulate the soil pressure applied to the specimen model 8 by both sides of the station structure.

[0023] like Figure 1 As shown, a reaction frame 14 is fixedly connected to the reaction wall base 2. The longitudinal actuation mechanism 12 includes a longitudinal actuation mechanism base 121 fixedly connected to the reaction frame 14. A longitudinal servo actuator 122 is provided at the lower end of the longitudinal actuation mechanism base 121. The power output end of the longitudinal servo actuator 122 is connected to the top of the precast upper column 84. The lower end of the longitudinal actuation mechanism 12 acts on the top of the precast upper column 84 and applies axial pressure to simulate the top soil pressure and road load.

[0024] The pseudo-dynamic testing equipment of the present invention simulates the earth pressure transmitted laterally from the station structure by fixing the clamping bracket to the specimen model 8. It simulates the earth pressure and road load transmitted from the upper part of the station structure by applying axial compression to the top of the precast upper column 84. It simulates the seismic response of the node under lateral seismic action by applying reciprocating load to the top side of the precast upper column 84. By simulating actual constraint conditions, it conforms to the stress characteristics of underground structures and improves the accuracy of test data.

[0025] Example 2: This invention also discloses a pseudo-dynamic test method for beam-slab-column joints of an assembled underground station structure, using the aforementioned pseudo-dynamic test device, including the following loading steps: (I) Installation of specimen model 8: Install the hinge support 7 and the sliding support 11 on the reaction wall base 2, hoist the specimen model 8 and fix it to the hinge support 7 and the sliding support 11; according to the installation position of the specimen model 8, install and fix the transverse actuation mechanism 4, the longitudinal actuation mechanism 12, the clamping bracket and the specimen model 8 respectively; specifically, support the lower end of the precast lower column 82 of the specimen model 8 on the hinge support 7, connect the two I-beams 9 and the two brackets 10 of the clamping bracket to the four sides of the precast floor slab 81 and the precast longitudinal beam 83 and fix them, and then fix the two I-beams 9 to the corresponding sliding support 11.

[0026] (II) Simulated dynamic test of specimen model 8: Connect the transverse actuation mechanism 4 and the longitudinal actuation mechanism 12 to the external power supply, and adjust the power accordingly according to the earthquake intensity to be simulated. The reciprocating load applied by the transverse actuation mechanism 4 is used to simulate the vibration of specimen model 8. The axial pressure of the longitudinal actuation mechanism 12 and the preload of the clamping rod 10 can be adjusted as needed to simulate different pre-earthquake stress states of specimen model 8. The simulation test data is recorded and compared, and the earthquake failure process and collapse mode of specimen model 8 can be observed intuitively.

[0027] Embodiment 2 of this invention compares the graded loading system with the seismic performance level classification of underground station structures based on inter-story drift ratio (IDR) (as shown in Table 1); the lateral actuation mechanism 4 adopts a dynamic loading system (as shown in Table 1). Figure 3 (as shown in Table 2).

[0028] Table 1 IDR Comparison Table: .

[0029] Table 2. Dynamic loading regime of lateral actuation mechanism 4: .

[0030] The method of this invention uses a graded loading system and compares it with the seismic performance level classification of underground station structures based on inter-story drift angle (IDR). This avoids the defect that the similarity ratio of the soil-structure dynamic interaction system cannot be unified. Moreover, the method of extracting key nodes is less affected by size effects than the overall model test, and it is easier to observe the evolution of structural damage.

[0031] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A pseudo-dynamic testing device for assembling beam-slab-column joints of an underground station structure, characterized in that, include: The specimen model (8) is composed of multiple precast components, including precast floor slabs (81), precast lower columns (82), precast longitudinal beams (83) and precast upper columns (84). The reaction wall includes a vertically arranged reaction wall (1) and a horizontally arranged reaction wall base (2) at the bottom of the reaction wall (1). The reaction wall (1) and the reaction wall base (2) are integrally formed. The transverse actuation mechanism (4) is fixedly installed horizontally along the axial direction on the inner side of the reaction wall vertical wall (1) and connected to the top of the precast upper column (84) to transmit reciprocating loads to simulate transverse seismic action. Hinged support (7), which is fixedly connected to the reaction wall base (2); The clamping bracket is fixedly connected to the specimen model (8) and is used to simulate the soil pressure applied to the specimen model (8) by both sides of the station structure. The clamping bracket includes two I-beams (9) and two scaffolds (10) respectively installed at both ends and sides of the precast floor slab (81). The lower end of the I-beams (9) is provided with a sliding support (11) fixedly connected to the reaction wall base (2). The sliding support (11) is used to limit the spatial height position of the precast floor slab (81). The longitudinal actuation mechanism (12) is fixedly connected to the reaction frame (14) on the reaction wall base (2). The lower end of the longitudinal actuation mechanism (12) acts on the top of the precast upper column (84) and applies axial pressure to simulate the top soil pressure and road load.

2. The pseudo-dynamic test device for beam-slab-column joints of an assembled underground station structure according to claim 1, characterized in that, The lateral actuation mechanism (4) includes a lateral actuation mechanism base (41) fixedly installed axially on the inner side of the reaction wall vertical wall (1). A lateral servo actuator (42) is hinged on the lateral actuation mechanism base (41). The power output end of the lateral servo actuator (42) is connected to a ring clamp (13). The ring clamp (13) is fitted onto the top of the precast upper column (84).

3. The pseudo-dynamic test device for beam-slab-column joints of an assembled underground station structure according to claim 1, characterized in that, The longitudinal actuation mechanism (12) includes a longitudinal actuation mechanism base (121) fixedly connected to the reaction frame (14). A longitudinal servo actuator (122) is provided at the lower end of the longitudinal actuation mechanism base (121). The power output end of the longitudinal servo actuator (122) is connected to the top of the precast upper column (84).

4. The pseudo-dynamic test device for beam-slab-column joints of an assembled underground station structure according to claim 1, characterized in that, The precast lower column (82) has an extended longitudinal bar (821) at the top, and the extended length of the longitudinal bar (821) is not less than 0.9m; the precast upper column (84) has a built-in grouting sleeve (841) at the bottom, and the grouting sleeve (841) is used to align and connect with the extended longitudinal bar (821) of the precast lower column (82).

5. The pseudo-dynamic test device for beam-slab-column joints of an assembled underground station structure according to claim 4, characterized in that, The precast longitudinal beam (83) has a circular cavity (831) in the center separated by a steel corrugated pipe, and the circular cavity (831) is used for the outward longitudinal reinforcement (821) of the precast lower column (82) to pass through.

6. The pseudo-dynamic test device for beam-slab-column joints of an assembled underground station structure according to claim 5, characterized in that, The top of the precast longitudinal beam (83) is provided with multiple U-shaped lap bars (832) along the beam body direction. The precast floor slab (81) is provided with connecting steel bars (811) on the side corresponding to the precast longitudinal beam (83) and is connected to the precast longitudinal beam (83) through U-shaped lap bars (832). After the precast longitudinal beam (83) and the precast floor slab (81) are spliced ​​together, an upper open cavity is formed for post-poured concrete.

7. A pseudo-dynamic test method for beam-slab-column joints of an assembled underground station structure, characterized in that, The pseudo-dynamic testing device as described in any one of claims 1 to 6 includes the following loading steps: Step 1: Install the hinge support (7) and sliding support (11) on the reaction wall base (2) respectively, and hoist the specimen model (8) and fix it with the hinge support (7); Step 2: Install and fix the transverse actuation mechanism (4), the longitudinal actuation mechanism (12), the clamping bracket, and the specimen model (8) respectively; Step 3: Apply reciprocating load to simulate earthquake action through the transverse actuation mechanism (4), adjust the axial pressure and the preload of the strut (10) through the longitudinal actuation mechanism (12), record the test data and analyze the node failure process.

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