Effects of Initial Imperfection of Bolted End-plate Connections in the Reliability of Steel Portal Frames

Abstract

The majority of industrial buildings in China are steel portal frame constructions. An increasingly large number of industrial buildings are being built in coastal areas subject to Typhoon. The high strength bolted end-plate connection is main type of the connections used widely in industrial construction. There are two kinds of end-plate connections in steel portal frames: flush and extend end-plate connections. The main initial imperfection of bolted end-plate connection lies in which the thickness of end-plate and column flange can’t meet the code provisions based on a field investigation. Considering the effect of initial imperfection, the actual behavior of end-plate connections in steel portal frames is seldom fully rigid. The true behavior of the connections is usually semi-rigid. Neglecting the real behavior of connections in the analysis may lead to unrealistic predictions of the response and reliability of steel portal frames. This paper considers the effects of semi-rigid behavior of the connections in the finite element analysis and reliability analysis of steel portal frames. Assuming that the loads and the resistance of members are random variables, then the Monte Carlo simulation technique is used to estimate the failure probability of steel portal frame system. The results confirm that the thickness of end-plate has a significant effect on safety of steel portal frame.