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Steel Construction Published the List of Highly Influential Articles of 2020
2023 Vol. 38, No. 8
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2023, 38(8): 1-13.
doi: 10.13206/j.gjgS23021502
Abstract
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Abstract:
In order to explore the analysis method and applicability of prefabricated modular steel frame structures, the multi-scale finite element model is established in the ABAQUS finite element software to analyze static and dynamic characteristic. The static characteristic of beam element, solid element and multi-scale joint calculation models are compared and analyzed. The differences of beam element, solid element and multi-scale frame calculation model are compared from two aspects of internal force analysis and model analysis of modular structure. In addition, the multi-scale model is applied to the dynamic elastic-plastic time history analysis of the modular steel frame structure, and the dynamic response differences between the beam element and the multi-scale frame 6 to 12-story model are compared and analyzed. The results show that internal multi-point constraint method in ABAQUS can achieve the connection between beam element and solid element; the calculation accuracy of the multi-scale model is in good agreement with that of the solid element. Comparing the two models, the multi-scale calculation model can increase the calculation efficiency by about 40%; the dynamic modal analysis shows that the natural frequencies of the multi-scale model and the solid element are basically the same, which verifies the reliability of the multi-scale model calculation results; when the number of modular structure floors exceeds 10, the calculation accuracy of the beam element calculation model is greatly reduced, while the calculation accuracy of the multi-scale calculation model is stable.
In order to explore the analysis method and applicability of prefabricated modular steel frame structures, the multi-scale finite element model is established in the ABAQUS finite element software to analyze static and dynamic characteristic. The static characteristic of beam element, solid element and multi-scale joint calculation models are compared and analyzed. The differences of beam element, solid element and multi-scale frame calculation model are compared from two aspects of internal force analysis and model analysis of modular structure. In addition, the multi-scale model is applied to the dynamic elastic-plastic time history analysis of the modular steel frame structure, and the dynamic response differences between the beam element and the multi-scale frame 6 to 12-story model are compared and analyzed. The results show that internal multi-point constraint method in ABAQUS can achieve the connection between beam element and solid element; the calculation accuracy of the multi-scale model is in good agreement with that of the solid element. Comparing the two models, the multi-scale calculation model can increase the calculation efficiency by about 40%; the dynamic modal analysis shows that the natural frequencies of the multi-scale model and the solid element are basically the same, which verifies the reliability of the multi-scale model calculation results; when the number of modular structure floors exceeds 10, the calculation accuracy of the beam element calculation model is greatly reduced, while the calculation accuracy of the multi-scale calculation model is stable.
2023, 38(8): 14-21.
doi: 10.13206/j.gjgS23041202
Abstract:
Steel tubular-corrugated steel plate confined concrete composite column has been applied in actual project due to its good mechanical properties and fast construction speed. In order to study the axial compression behavior of steel tubular-corrugated steel plate confined concrete composite column, the FE model was established and nonlinear finite element analysis was carried out by using ABAQUS finite element software based on the six completed groups of axial compression tests. Combined with the results of axial compression tests, the reliability and applicability of the FE model were proved from the failure mode of specimens and load-displacement curves of corrugated steel plate. Based on the verified FE model, a large number of parametric analyses were proceeded, which included concrete strength, diameter-width ratio, yield strength of corrugated steel plate and thickness of corrugated steel plate, the influence of different parameters on the bearing capacity, initial stiffness, strength index and ductility of steel tubular-corrugated steel plate confined concrete composite column were explored. The simulation results showed that increasing the material strength would improve the bearing capacity of the specimen, but had little effect on the strength index. Increasing the diameter to width ratio can effectively improve the ultimate bearing capacity, strength index and ductility of the specimen, but the corresponding steel ratio of the specimen will also increase. Increasing the thickness of corrugated steel plate will not improve the bearing capacity of the specimen, but will obviously improve the ductility. Finally, the stability performance of steel tubular-corrugated steel plate confined concrete composite column was analyzed. Based on the comprehensive consideration of the cross-section and material properties of the composite column, the calculation method of slenderness ratio was proposed. By introducing the initial imperfection, the FE models of steel tubular-corrugated steel plate confined concrete composite column with different slenderness ratios were established. The influence of different slenderness ratios on its mechanical mechanism and bearing capacity was studied and the calculation methods of national codes were introduced to compare with the simulation results. The comparison results showed that the design value of the ultimate bearing capacity of steel tubular-corrugated steel plate confined concrete composite column was too large in the existing codes, which could not accurately predict the bearing capacity of the composite column. Thus, the calculation formula of stability coefficient and axial compression capacity of steel tubular-corrugated steel plate confined concrete composite column was modified based on FE simulation results.
Steel tubular-corrugated steel plate confined concrete composite column has been applied in actual project due to its good mechanical properties and fast construction speed. In order to study the axial compression behavior of steel tubular-corrugated steel plate confined concrete composite column, the FE model was established and nonlinear finite element analysis was carried out by using ABAQUS finite element software based on the six completed groups of axial compression tests. Combined with the results of axial compression tests, the reliability and applicability of the FE model were proved from the failure mode of specimens and load-displacement curves of corrugated steel plate. Based on the verified FE model, a large number of parametric analyses were proceeded, which included concrete strength, diameter-width ratio, yield strength of corrugated steel plate and thickness of corrugated steel plate, the influence of different parameters on the bearing capacity, initial stiffness, strength index and ductility of steel tubular-corrugated steel plate confined concrete composite column were explored. The simulation results showed that increasing the material strength would improve the bearing capacity of the specimen, but had little effect on the strength index. Increasing the diameter to width ratio can effectively improve the ultimate bearing capacity, strength index and ductility of the specimen, but the corresponding steel ratio of the specimen will also increase. Increasing the thickness of corrugated steel plate will not improve the bearing capacity of the specimen, but will obviously improve the ductility. Finally, the stability performance of steel tubular-corrugated steel plate confined concrete composite column was analyzed. Based on the comprehensive consideration of the cross-section and material properties of the composite column, the calculation method of slenderness ratio was proposed. By introducing the initial imperfection, the FE models of steel tubular-corrugated steel plate confined concrete composite column with different slenderness ratios were established. The influence of different slenderness ratios on its mechanical mechanism and bearing capacity was studied and the calculation methods of national codes were introduced to compare with the simulation results. The comparison results showed that the design value of the ultimate bearing capacity of steel tubular-corrugated steel plate confined concrete composite column was too large in the existing codes, which could not accurately predict the bearing capacity of the composite column. Thus, the calculation formula of stability coefficient and axial compression capacity of steel tubular-corrugated steel plate confined concrete composite column was modified based on FE simulation results.
2023, 38(8): 22-33.
doi: 10.13206/j.gjgS23031901
Abstract:
In order to study the ultimate bearing capacity and failure mode of single side high strength bolt connection of steel pipe bundle, the monotone drawing test and finite element numerical simulation of single side high strength bolt connection of steel pipe bundle were carried out, and the influence of end plate thickness and steel pipe bundle thickness on the connection bearing capacity and failure mode was analyzed. Based on the test results and finite element parametric analysis results, the theoretical formula of initial tensile stiffness for single side high strength bolt connection of steel pipe bundle is derived. Firstly, by changing the thickness of the end plate, the thickness of the steel tube bundle and the type of the bolt, 5 steel tube bundle single side high strength bolt connection specimens were designed and made for the monotonic drawing test. Moreover, in order to make the test results biased to the safety, specimens were without filling concrete, and the beneficial effect of concrete was not considered. Secondly, the finite element numerical simulation is carried out on the single side high strength bolt connection of the steel pipe bundle, and the finite element simulation results are compared with the test results to verify the correctness of the finite element modeling method, and the same modeling method is used to carry out parametric analysis on the single side high strength bolt connection of the steel pipe bundle. The influence of tube bundle thickness and end plate thickness on mechanical properties of single side high strength bolt connection of tube bundle was further investigated. Finally, according to the test results and finite element parametric analysis results, the initial tensile stiffness formula of steel pipe bundle single side high strength bolt connection was derived by component method. The theoretical data was compared with the finite element simulation results to verify the accuracy of the formula. The results show that the failure mode of single side high strength bolt connection of steel pipe bundle is as follows: steel pipe bundle bulging, plastic deformation of bolt hole, bending of the outer sleeve of single side high strength bolt leading to the removal of single side high strength bolt, which is different from the failure mode that bolt hole of ordinary high strength bolt connection of steel pipe bundle is broken. Increasing the thickness of steel pipe bundle can significantly improve the bearing capacity and initial tensile stiffness of single side high strength bolt connection of steel pipe bundle. Although the bearing capacity and plastic deformation capacity of single side high strength bolt connection are lower than those of ordinary high strength bolt connection, there is no need to reserve installation hand holes during installation, so as to avoid the adverse effects of welding construction on the mechanical properties of cold-formed thin-wall steel. The finite element numerical simulation results are consistent with the experimental results, which proves that the finite element modeling method is reliable, and the parametric analysis results further show that the mechanical properties of steel pipe bundle single side high strength bolt are mainly controlled by the thickness of steel pipe bundle, but are less affected by the thickness of end plate. The theoretical stiffness derived from the initial tensile stiffness formula of steel tube bundle single side high strength bolt connection by component method is in good agreement with the finite element parameter analysis results, which proves that the initial tensile stiffness formula of steel tube bundle single side high strength bolt connection has good reliability.
In order to study the ultimate bearing capacity and failure mode of single side high strength bolt connection of steel pipe bundle, the monotone drawing test and finite element numerical simulation of single side high strength bolt connection of steel pipe bundle were carried out, and the influence of end plate thickness and steel pipe bundle thickness on the connection bearing capacity and failure mode was analyzed. Based on the test results and finite element parametric analysis results, the theoretical formula of initial tensile stiffness for single side high strength bolt connection of steel pipe bundle is derived. Firstly, by changing the thickness of the end plate, the thickness of the steel tube bundle and the type of the bolt, 5 steel tube bundle single side high strength bolt connection specimens were designed and made for the monotonic drawing test. Moreover, in order to make the test results biased to the safety, specimens were without filling concrete, and the beneficial effect of concrete was not considered. Secondly, the finite element numerical simulation is carried out on the single side high strength bolt connection of the steel pipe bundle, and the finite element simulation results are compared with the test results to verify the correctness of the finite element modeling method, and the same modeling method is used to carry out parametric analysis on the single side high strength bolt connection of the steel pipe bundle. The influence of tube bundle thickness and end plate thickness on mechanical properties of single side high strength bolt connection of tube bundle was further investigated. Finally, according to the test results and finite element parametric analysis results, the initial tensile stiffness formula of steel pipe bundle single side high strength bolt connection was derived by component method. The theoretical data was compared with the finite element simulation results to verify the accuracy of the formula. The results show that the failure mode of single side high strength bolt connection of steel pipe bundle is as follows: steel pipe bundle bulging, plastic deformation of bolt hole, bending of the outer sleeve of single side high strength bolt leading to the removal of single side high strength bolt, which is different from the failure mode that bolt hole of ordinary high strength bolt connection of steel pipe bundle is broken. Increasing the thickness of steel pipe bundle can significantly improve the bearing capacity and initial tensile stiffness of single side high strength bolt connection of steel pipe bundle. Although the bearing capacity and plastic deformation capacity of single side high strength bolt connection are lower than those of ordinary high strength bolt connection, there is no need to reserve installation hand holes during installation, so as to avoid the adverse effects of welding construction on the mechanical properties of cold-formed thin-wall steel. The finite element numerical simulation results are consistent with the experimental results, which proves that the finite element modeling method is reliable, and the parametric analysis results further show that the mechanical properties of steel pipe bundle single side high strength bolt are mainly controlled by the thickness of steel pipe bundle, but are less affected by the thickness of end plate. The theoretical stiffness derived from the initial tensile stiffness formula of steel tube bundle single side high strength bolt connection by component method is in good agreement with the finite element parameter analysis results, which proves that the initial tensile stiffness formula of steel tube bundle single side high strength bolt connection has good reliability.
2023, 38(8): 34-41.
doi: 10.13206/j.gjgS22112601
Abstract:
Compared with concrete stairs, steel stairs with light deadweight, large span, high bearing capacity, good overall stiffness and other characteristics are easy to install and low cost, and are widely used in various commercial and office buildings. However, the design methods of some structures with large span and irregular shape are not specified in the existing domestic standard drawings. Aiming at the complicated calculation problems caused by the irregular shape and large span of the steel structure spiral staircase at the sunken square of a business center in Jinan, this paper proposes four different structural design schemes of box girder, beam, atlas plate and box step. The finite element analysis software SAP 2000 is used to establish the overall model of the steel spiral staircase, and the static analysis and modal analysis are carried out for the four schemes. The cross-section design of the spiral staircase component is compeleted, and the comfort degree of each scheme is analyzed by using three different pedestrian excitation load cases. The four schemes are compared from the aspects of structural stiffness, component strength and overall comfort of stairs. The mechanical properties of stairs with different structural forms and the same shape are studied. The advantages and disadvantages of each structural design scheme are obtained, and the final design scheme is determined. The analysis results show that the four schemes can meet the design requirements in terms of deformation, strength and comfort. The maximum displacement of the four schemes occurs in the middle of the spiral staircase, and the deflection of scheme 2 is the largest, which indicates that sealing the bottom of the staircase to form a box shaped closed section of the stair treads can effectively increase the stiffness of the stairs. There is a large stress concentration at the turning point where the rest platform is connected to the ladder. By considering the nonlinearity of the material, the nonlinear analysis of the staircase shows that the stress concentration has little influence on the strength of the staircase. For the area of stress concentration, the steel box girder can be thickened from 16 mm to 20 mm thick.The focus of comfort research is to control the structural acceleration under dynamic load. When the natural frequency meets the requirements, the acceleration response will still be too large. Therefore, for comfort problems of complex structure, time history analysis should be adopted, combined with their accelerations in stable state for comprehensive evaluation. The design results of the four schemes are compared, and the box step stair is determined as the final design scheme after comprehensive consideration of the mechanical characteristics, overall aesthetic degree, construction convenience, stair cost, etc.
Compared with concrete stairs, steel stairs with light deadweight, large span, high bearing capacity, good overall stiffness and other characteristics are easy to install and low cost, and are widely used in various commercial and office buildings. However, the design methods of some structures with large span and irregular shape are not specified in the existing domestic standard drawings. Aiming at the complicated calculation problems caused by the irregular shape and large span of the steel structure spiral staircase at the sunken square of a business center in Jinan, this paper proposes four different structural design schemes of box girder, beam, atlas plate and box step. The finite element analysis software SAP 2000 is used to establish the overall model of the steel spiral staircase, and the static analysis and modal analysis are carried out for the four schemes. The cross-section design of the spiral staircase component is compeleted, and the comfort degree of each scheme is analyzed by using three different pedestrian excitation load cases. The four schemes are compared from the aspects of structural stiffness, component strength and overall comfort of stairs. The mechanical properties of stairs with different structural forms and the same shape are studied. The advantages and disadvantages of each structural design scheme are obtained, and the final design scheme is determined. The analysis results show that the four schemes can meet the design requirements in terms of deformation, strength and comfort. The maximum displacement of the four schemes occurs in the middle of the spiral staircase, and the deflection of scheme 2 is the largest, which indicates that sealing the bottom of the staircase to form a box shaped closed section of the stair treads can effectively increase the stiffness of the stairs. There is a large stress concentration at the turning point where the rest platform is connected to the ladder. By considering the nonlinearity of the material, the nonlinear analysis of the staircase shows that the stress concentration has little influence on the strength of the staircase. For the area of stress concentration, the steel box girder can be thickened from 16 mm to 20 mm thick.The focus of comfort research is to control the structural acceleration under dynamic load. When the natural frequency meets the requirements, the acceleration response will still be too large. Therefore, for comfort problems of complex structure, time history analysis should be adopted, combined with their accelerations in stable state for comprehensive evaluation. The design results of the four schemes are compared, and the box step stair is determined as the final design scheme after comprehensive consideration of the mechanical characteristics, overall aesthetic degree, construction convenience, stair cost, etc.
2023, 38(8): 42-45.
doi: 10.13206/j.gjgS23080120
Abstract:
Hierarchy of a structure is introduced, the force-displacement relation of a lower level is the constitutive relation of the upper level. In plate-like space truss, the compression-shortening relation of a chord is the constitutive relation of its compressed region when it is simplified as a plate. The compressed bars are of brittle nature, similar to concrete in a slab, while tension chord is similar to the tensile reinforcement. For brittle failure, the required reliability index is 3.7, greater than 3.2 for ductile failure, this implies that an addition safety factor is required for compression chords. For seismic design, brittle failure is prevented by capacity design technique, which is realized by strong column factor and strong joint factors in design check. This demands that a strong chord factor is necessary to achieve a ductile space truss. The paper proposes the value for this strong compression factor.
Hierarchy of a structure is introduced, the force-displacement relation of a lower level is the constitutive relation of the upper level. In plate-like space truss, the compression-shortening relation of a chord is the constitutive relation of its compressed region when it is simplified as a plate. The compressed bars are of brittle nature, similar to concrete in a slab, while tension chord is similar to the tensile reinforcement. For brittle failure, the required reliability index is 3.7, greater than 3.2 for ductile failure, this implies that an addition safety factor is required for compression chords. For seismic design, brittle failure is prevented by capacity design technique, which is realized by strong column factor and strong joint factors in design check. This demands that a strong chord factor is necessary to achieve a ductile space truss. The paper proposes the value for this strong compression factor.
