The Influence Of Openings On The Hysteretic Behavior Of Partially Restrained Steel Frame With RC Infill Walls

Partially restrained steel frame with RC infill walls(PSRCW)is composed of RC infill walls,partially restrained steel frames and shear connectors.The Partially restrained connections have good rotation ability to avoid brittle fracture.The steel frame can be used as boundary members to resist all the vertical loads and most overturning moments.RC infilled walls can bear most of the horizontal loads,which significantly increases the structure’s lateral stiffness.PSRCW structure combines the advantages of steel frame and RC shear wall to make up for their shortcomings,improve the structure’s ductility and energy dissipation capacity,and effectively reduce the lateral displacement of the structure.With the gradual improvement of people’s requirements for the structure-function,it is inevitable to use the reinforced concrete shear wall structure with openings.The influence of openings on the hysteretic behavior of partially restrained steel frames filled with RC wall structures is not clear.The research work carried out in this paper is of great significance to improve the design method of partially restrained steel frames with RC infill walls and promote the engineering application of this kind of structure.In this paper,experimental study and finite element simulation are used to study the PSRCW structure with openings.(1)In this paper,four one-bay,two-story test specimens on one-third scale are designed and tested under the horizontal low reversed cyclic loading.The two specimens are cast-in-place,the door and window openings are arranged in the middle of the wall,the other two are prefabricated,and the door and window openings are eccentric.Based on the experimental study,the influence of opening type,opening location,assembly mode on failure mode,hysteretic performance,horizontal bearing capacity,lateral stiffness,strength degradation law,deformation capacity,and energy dissipation capacity of partially restrained steel frame with RC infill walls are studied.(2)In this paper,the local performance of partially restrained steel frame with RC infill walls with openings are studied by means of experiments,which mainly include the shear deformation ability of the infill wall with openings,the performance of partially restrained connections,the performance of shear connectors,the laws of interface slip,the laws of interface separation,and the internal force distribution law of PSRCW structure with openings,etc.(3)Based on the finite element method,12 series of 30 PSRCW specimens were established.The lateral bearing capacity,lateral stiffness degradation,internal force distribution relationship,and failure mode of the PSRCW were analyzed.The influence of design parameters such as the door opening size,door opening location,window opening size,window opening location,opening rate,floor number,infilled wall thick Ness,axial compression ratio,steel column section area,concrete strength grade,and height span ratio was studied.Give relevant conclusions based on the above research.In order to systematically study the out-of-plane performance of partially-restrained steel frame with RC infill walls,the base specimen of partially-restrained steel frame with RC infill walls was designed,and 11 series of 27 models are derived,including floor number,steel column section,height span ratio,axial compression ratio,number of steel beam stiffeners,wall thick Ness,concrete strength,joint type,opening position and opening rate.The finite element analysis is carried out by using ABAQUS program,and the influence of relevant design parameters on the out-of-plane bearing capacity,out-of-plane stiffness,the distribution of out-of-plane force,and failure mode of partially-restrained steel frame with RC infill walls is studied.The results show that: the main influencing factors of out-of-plane bearing capacity and out-of-plane stiffness of partially-restrained steel frame with RC infill walls are the number of floors,section size of steel column,axial compression ratio,and number of steel beam stiffeners;the main influencing factors of internal force distribution are the number of floors,height span ratio,number of steel beam stiffeners,the thick Ness of infilled wall,opening rate and opening position;The failure mode of partially restrained steel frame with RC infill wall structure changes with the change of floor number,height span ratio or the number of steel beam stiffeners.The research results can provide a basis for further research and engineering design.