A method for constructing an assembled steel pipe concrete column foot joint seismic performance analysis model

Abstract

The application discloses a construction method of an assembled steel pipe concrete column foot joint seismic performance analysis model, which comprises the following steps: step one: the steel pipe concrete column foot joint is decomposed into a fiber beam unit part, a macro unit part and a connecting part; the fiber beam part comprises a steel pipe concrete column and a reinforced rib bottom plate, the macro unit part comprises ground anchoring bolts, a shear element and a compression concrete foundation; and the connecting part comprises a rigid connection for describing the offset distance of the column and the bottom plate and a fixed connection of the foundation and the ground; step two: macro spring units are used to model the connecting components; step three: the model of the anchoring bolts in the column foot connecting joint domain is endowed; step four: the model of the shear element in the column foot connecting joint domain is endowed; and step five: the model of the compression side concrete foundation in the column foot connecting joint domain is endowed. The method can accurately simulate the loading and unloading performance of the assembled steel pipe concrete column foot and the "idling" phenomenon after unloading, and can reasonably and efficiently evaluate the seismic performance of the steel pipe concrete column foot.

Description

Technical Field

[0001] This invention relates to the technical field of building engineering, specifically a method for constructing a seismic performance analysis model for prefabricated steel-concrete composite column base joints. Background Technology

[0002] my country's construction industry is primarily based on on-site construction. This traditional production method suffers from low industrialization, extensive design and construction, unstable building quality, low construction efficiency, high labor demand, significant material waste and construction waste, and substantial resource and energy consumption. It fails to meet the requirements of sustainable development through energy conservation and environmental protection. With the acceleration of my country's "building industrialization and housing industrialization" process, the trend of housing industrialization is becoming increasingly apparent. A revolution is underway in construction production methods, namely the gradual expansion of new prefabricated building construction. The application of new prefabricated reinforced concrete structures has once again become a research hotspot. As a crucial component connecting the upper main structure and the lower foundation, the column base joint's mechanical properties directly affect the overall frame's mechanical performance. Therefore, accurately defining the seismic performance of the column base is particularly important.

[0003] During the design process, accurately simulating the loading and unloading performance of this type of prefabricated steel-concrete composite column base and the "idling" phenomenon after unloading, and reasonably and efficiently evaluating the seismic performance of the steel-concrete composite column base, can provide a foundation and basis for further nonlinear time history analysis of frames composed of such prefabricated joints. Therefore, it is necessary to design a seismic performance analysis model for prefabricated steel-concrete composite column base joints. Summary of the Invention

[0004] The purpose of this invention is to provide a method for constructing a seismic performance analysis model for prefabricated steel-concrete composite column base joints. This seismic performance analysis model can accurately simulate the loading and unloading performance of prefabricated steel-concrete composite column bases and the phenomenon of "idling" after unloading, and reasonably and efficiently evaluate the seismic performance of steel-concrete composite column bases.

[0005] To achieve the objectives of this invention, the following technical solution is adopted.

[0006] A method for constructing a seismic performance analysis model for prefabricated steel-concrete composite column base joints includes the following steps: Step 1: Decompose the concrete-tube steel column base joint into three regions: fiber beam element part, macro element part, and connection part; the fiber beam part includes the concrete-tube steel column and the reinforced ribbed base plate; the macro element part includes the ground anchor bolts, shear members, and the compressed concrete foundation; the connection part includes the rigid connection describing the offset distance between the column and the base plate, and the fixed connection between the foundation and the ground.

[0007] Step 2: Model each connecting component using macro spring elements.

[0008] Step 3: Assign the model to the anchor bolts in the column base connection node domain.

[0009] Step 4: Assign the model to the shear member in the column base connection node domain.

[0010] Step 5: Assign a model to the concrete foundation on the compression side of the column base connection node domain.

[0011] A further preferred approach is to model each connecting component using macroscopic spring elements, including compression-only foundation concrete elements, anchor bolt tension elements, and lateral shear elements. All of these elements are zero-length spring elements, meaning that the two nodes of each element are located at the same position.

[0012] Further preferred: The model of the anchor bolt in the column base connection node domain is given as follows: In the column base connection node domain, the anchor bolt is used as a component to connect the base plate and the concrete foundation. The force-displacement curve relationship of the anchor bolt under cyclic load is simulated. The defined values ​​of each point of the skeleton curve are obtained from the tensile test of the anchor bolt.

[0013] Further optimized: The model of the shear member in the column base connection node domain is defined by the shear member through zero-length spring element, simulating the force-displacement curve relationship of the shear member under cyclic load, wherein the defined values ​​of each point of the skeleton curve are derived from the shear member through experiments.

[0014] Further optimized: The model of the concrete foundation on the compression side of the column base connection node domain is assigned as a spring model of the concrete foundation on the compression side, simulating only the uniaxial material under compression. In order to characterize the response of the spring-simulated concrete under compression, only two parameters are needed, namely stiffness Kc and strength Fc. The compressive strength and compressive stiffness of the concrete on the compression side are obtained according to European standard 3 "Design of steel structures - Part 1-8: Design of joints" (EN1993-1-8:2005). In this model, after the base plate yields, the spring-simulated concrete can only be activated by compression when the screw spring returns to zero displacement.

[0015] This seismic performance analysis model accurately simulates the loading and unloading performance of prefabricated steel-concrete composite column bases and the "free-spinning" phenomenon after unloading, providing a reasonable and efficient assessment of the seismic performance of steel-concrete composite column bases. Compared to previous efficient analysis models that simulate the rotation (bending) capacity of column base nodes by setting a nonlinear rotation spring at the column base, this model requires prior knowledge of the node's hysteresis curve model (specific resistance rotation curve). If different node configurations are included, repeated calculations are needed under different parameter conditions, and different mechanical constitutive curves must be assigned to the rotation spring. For example, the mechanical properties and failure modes of the column base will change under different axial forces. The efficient analysis model proposed in this paper can directly predict the mechanical properties and failure modes of specimens under different parameter conditions, unaffected by node type or load conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the test specimen; Figure 2 yes Figure 1 A schematic diagram of the fiber cross-section and macroscopic spring unit in the model; Figure 3 It is a model based on fiber beam elements and macroscopic elements; Figure 4 This is a schematic diagram of the macroscopic unit model of the prefabricated steel-concrete composite column base node; Figure 5 This is a schematic diagram of the second macroscopic unit model of the prefabricated steel-concrete composite column base node; Figure 6 It is the force-displacement curve relationship of the anchor bolt under cyclic loading; Figure 7 It is the force-displacement curve relationship of a shear member under cyclic loading; Figure 8 It is the pressure-displacement relationship of the concrete foundation on the compression side; Figure 9 Comparison of finite element model of column base node with experimental force-displacement curve Figure 1 ; Figure 10 Comparison of finite element model of column base node with experimental force-displacement curve Figure 2 ; Figure 11 Comparison of finite element model of column base node with experimental force-displacement curve Figure 3 ; Figure 12 Comparison of finite element model of column base node with experimental force-displacement curve Figure 4 ; Figure 13 Comparison of finite element model of column base node with experimental force-displacement curve Figure 5 ; Figure 4 and Figure 5 This section describes the component connection between the column base plate and the concrete foundation for different types of anchor bolt arrangements. The macroscopic unit includes only compression foundation concrete units, anchor bolt tension units, and lateral shear units. All of these units are zero-length spring units, meaning that the two nodes of the unit are located at the same position. Figure 6 The defined values ​​of each point on the medium skeleton curve are derived from the tensile test of the anchor bolt. Figure 7 The numerical values ​​for each point on the mid-frame curve are derived from shear member derivation experiments. (Utilizing...) Figure 8 The uniaxial material simulation shown only, under compression, requires only two parameters to characterize the response of spring-simulated concrete under compression: stiffness Kc and strength Fc. Figures 9 to 13The comparison between the experimental data and simulation results shows that the hysteresis curve and the skeleton curve fit well. This indicates that the proposed simulation method can effectively simulate the initial stiffness, flexural bearing capacity, and accurately capture the displacement corresponding to the failure point of this type of column base under cyclic loading. Detailed Implementation

[0017] To make the technical solution and advantages of this application clearer, the technical solution of the construction method for the seismic performance analysis model of prefabricated steel-concrete composite column base joint is described clearly and completely below with reference to the embodiments and accompanying drawings.

[0018] Example

[0019] A method for constructing a seismic performance analysis model for prefabricated steel-concrete composite column base joints includes the following steps: Step 1: Decompose the concrete-tube steel column base joint into three regions: fiber beam element part, macro element part, and connection part; the fiber beam part includes the concrete-tube steel column and the reinforced ribbed base plate, such as... Figure 1 Sections AA, BB, and CC are shown; the macroscopic unit includes ground anchor bolts, shear members, and compressed concrete foundations; the connection part includes rigid connections describing the offset distance between the column and the base plate, and fixed connections between the foundation and the ground, such as... Figure 3 The nodes a, b, a1, and b1 shown are connected to node c with rigid arms, and the rigidlink beam command is executed.

[0020] Step 2: Model each connecting component using macro spring elements.

[0021] Step 3: Assign the model to the anchor bolts in the column base connection node domain.

[0022] Step 4: Assign the model to the shear member in the column base connection node domain.

[0023] Step 5: Assign a model to the concrete foundation on the compression side of the column base connection node domain.

[0024] The connecting components are modeled using macroscopic spring elements, including compression-only foundation concrete elements, anchor bolt tension elements, and lateral shear elements. All of these elements are zero-length spring elements, meaning that the two nodes of the element are located at the same position. Figure 4 and Figure 5 The diagram illustrates the component connections between the column base plate and the concrete foundation using different types of anchor bolt arrangements.

[0025] The model for anchor bolts in the column base connection node domain is defined as follows: In the column base connection node domain, the anchor bolt acts as a component connecting the base plate to the concrete foundation, utilizing... Figure 6The model shown simulates the force-displacement curve relationship of an anchor bolt under cyclic loading, where the defined values ​​of each point on the skeleton curve are obtained from the tensile test of the anchor bolt.

[0026] The shear member model in the column base connection node domain is defined using zero-length spring elements, utilizing... Figure 7 The model simulates the force-displacement curve relationship of a shear member under cyclic loading, wherein the defined values ​​of each point on the skeleton curve are derived from the shear member derivation test.

[0027] The model of the column base connection node domain on the compression side of the concrete foundation is assigned as a spring model of the compression side concrete foundation, utilizing... Figure 8 The uniaxial material simulation shown only requires two parameters to characterize the spring-simulated concrete response under compression: stiffness Kc and strength Fc. The compressive strength and compressive stiffness of the concrete on the compression side are obtained according to European standard 3 "Design of steel structures - Part 1-8: Design of joints" (EN1993-1-8:2005). In this model, after the base plate yields, the spring-simulated concrete can only be activated by compression when the screw spring returns to zero displacement.

[0028] like Figures 9-13 As shown, the comparison between experimental data and simulation results reveals a good fit between the hysteresis curve and the skeleton curve. This indicates that the proposed simulation method can effectively simulate the initial stiffness, flexural bearing capacity, and accurately capture the displacement corresponding to the failure point of this type of column base under cyclic loading. Comparing the experimental data and the simulated hysteresis curves, the column base node analysis model proposed in this invention can effectively simulate the loading and unloading performance of this type of prefabricated steel-concrete composite column base and the "idling" phenomenon after unloading. These are crucial for the reasonable evaluation of the seismic performance of steel-concrete composite column bases. Secondly, compared to the refined finite element model, the proposed method is at least three orders of magnitude faster in computation time, significantly improving efficiency, and significantly reducing the required computer storage space and RAM.

[0029] The above description is not intended to limit this application, nor is this application limited to the examples described above. Any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of this application should fall within the protection scope of this application.

Claims

1. A method for constructing a seismic performance analysis model for prefabricated steel-concrete composite column base joints, characterized in that: Includes the following steps: Step 1: Decompose the steel-concrete composite column base node into three regions: fiber beam element part, macro element part, and connection part; the fiber beam part includes the steel-concrete composite column and the reinforced ribbed base plate; the macro element part includes the ground anchor bolts, shear members, and the compressed concrete foundation; the connection part includes the rigid connection describing the offset distance between the column and the base plate and the fixed connection between the foundation and the ground. Step 2: Model each connecting component using macroscopic spring elements; Step 3: Assign the model to the anchor bolts in the column base connection node domain; Step 4: Assign the model to the shear member in the column base connection node domain; Step 5: Assign a model to the concrete foundation on the compression side of the column base connection node domain; The macroscopic spring elements are used to model each connecting component, including the compression-only foundation concrete element, the anchor bolt tension element, and the lateral shear element. The model of the anchor bolt in the column base connection node domain is given as follows: In the column base connection node domain, the anchor bolt is used as a component to connect the base plate and the concrete foundation. The force-displacement curve relationship of the anchor bolt under cyclic load is simulated. The defined values ​​of each point of the skeleton curve are obtained from the tensile test of the anchor bolt. The model of the shear member in the column base connection node domain is defined by the shear member through zero-length spring element, and the force-displacement curve relationship of the shear member under cyclic load is simulated. The defined values ​​of each point of the skeleton curve are derived from the shear member test. The model of the concrete foundation on the compression side of the column base connection node domain is assigned as a spring model of the concrete foundation on the compression side, simulating only the uniaxial material under compression. To characterize the response of the spring-simulated concrete under compression, only two parameters are needed: stiffness Kc and strength Fc. The compressive strength and compressive stiffness of the concrete on the compression side are obtained according to European standard 3 "Design of steel structures - Part 1-8: Design of joints" (EN 1993-1-8:2005). After the base plate yields, the spring-simulated concrete can only be activated by compression when the screw spring returns to zero displacement.

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