Experimental Study And Finite Element Analysis Of Steel Frame With "X" CCA Walls

With the assembled building with steel-structure was promoted by the country,the assembled building with infilled steel frame was widely adopted in recent years.The material strength of assembled building with infilled frame had significant variability.The failure mode of assembled building with infilled frame was brittle failure and the seismic performance of it was difficultly predicted.The infill wall is only used as retaining component under the design process.The seismic calculation of steel frame structure doesn't include infill wall.But the mechanical performance of frame structure was affected with the infill wall in engineering practice.Moreover,infill wall appeared cracks under cyclic lateral loading.Therefore,in order to reduce the cracks of infill walls and improve the synergistic mechanical properties of steel frame with walls,it is necessary that the construction measures of infill walls were devised.Cellulose Fiber Cement Plates Autoclaved(CCA)walls are lightweight and high-strength walls.The cold-formed steel is skeleton of CCA walls.CCA are mounted on both sides of cold-formed steel.The CCA is filled with EPS lightweight concrete.In order to reduce the cracks of CCA walls and improve the synergistic mechanical properties of steel frame with CCA walls,a full-scale,one-bay and one-story steel frame with "X" CCA walls KJ-3X was designed.In order to study the failure characteristics of "X" CCA walls and the synergistic mechanical properties of steel frame with "X" CCA walls,full-scale,one-bay and one-story steel frame with "X" CCA walls KJ-3X and bare frame KJ-1 and steel frame with CCA walls KJ-2 was tested.Futhermore,the finite-element method analysis of three specimens were done.The results show that:(1)The CCA walls appear cracks when the drift angle is about 1/150.The "X" CCA walls appear cracks when the drift angle is about 1/100.The cracking of CCA walls is delayed by "X" constructional measures.In addition,"X" constructional measures can improve the stress concentrations of CCA walls.(2)Compared with bare frame,the initial stiffness of steel frame with CCA walls and steel frame with "X" CCA walls were improved.But stiffness degradation rate of steel frames with CCA walls and steel frame with "X" CCA walls was faster than bare frame due to cracked of CCA walls.(3)Compared with the conventional constructional measures,the initial stiffness of steel frame structure is reduced about 6% by "X" constructional measures.Moreover "X" constructional measures reduce stiffness descent speed of steel frame with CCA walls after the CCA walls appear cracks.(4)The failure characteristics of "X" CCA walls: initial,cracks of CCA walls mainly distributed in corner of CCA and CCA around the self-tapping screw;with the drift angle increased,CCA around the self-tapping screw was crushed.The cracks of assembly points of CCA extended;the final phase of experiment,the cracks of corner of CCA around loading point through.The top of CCA around unloading point was crushed.(5)The bearing capacity and hysteretic behavior of KJ-2 and KJ-3X were superior to KJ-1.Compared with the conventional configuration,"X" configuration had little effect on the bearing capacity and hysteretic behavior of steel frame with CCA walls.(6)The energy dissipation capacity of steel frame with CCA walls was improved due to CCA walls to be involved into the hysteretic energy dissipation of frame structure...