Wind-resistant safety analysis of light-weight steel portal frame structures

In order to investigate the wind-resistant safety conditions of light-weight steel portal frame structures,the wind pressures on the surface of a light-weight steel industrial building located at the southeast coastal area of China were measured by means of the wind-tunnel test technique.The wind loads under two most unfavorable wind directions obtained from the measured data and the loads determined from the load code for building structures and the technical specification for steel gable frame structures were applied to the unfavorable frame of the building.The nonlinear load-capacity analyses were then performed using the refined plate/shell element based finite element method,and the wind-resistant safety factors and ultimate-state failure modes of the frame were thereafter found.Analysis and comparison of the obtained wind-resistant safety factors under different load cases,indicate that the degrees of safety redundancy of the frame in consideration under the wind load determined from the steel gable frame specification and the extreme wind load from the wind tunnel test are relatively low,and the wind resistant design in accordance with the load code wind loading(no gust factor included)would probably lead the frame to an unsafe condition.A simple and effective beam-column connection enhancement measure is proposed thereafter,by which the safety level of the frame could be considerably improved and the sensibility to initial imperfections could be reduced.