Experimental and Numerical Investigation of Reverse Fault Rupture Interaction with Steel Frame Structures

During large earthquakes, a soil deposit overlaying an active fault is suspected to experience quasi static differential settlement produced by propagation of bedrock fault rupturing. Such differential surface dislocations can cause severe damage to engineering framed structures. Although there is partly extensive literature in this field, in most previous studies, super structures are not considered in the analysis directly. This paper investigates the interaction of a frame structure located on top of a soil sediment with a reverse fault rupturing. For this purpose, a series of reduced scale 1 g box tests with a steel frame structure were conducted. Then, the same related numerical models were calibrated and validated using physical modeling results. To compare different structural system behavior against surface fault rupture, two types of steel framed structure including moment resisting frame and concentric braced moment resisting frame were selected in the numerical analysis. A brief sensitivity analysis on structure position relative to fault outcrop is performed using numerical Finite Element (F.E.) method for both types of structural systems. Different responses for sediment and structure are considered. The results show that deformation mechanism of structural elements in these two systems are basically different. Based upon the results of this research, the moment frame is suspected to have more severe structural damage or even complete destruction.