Seismic Behavior of a Stone Curtain Wall System With Undercut Bolt Anchorage Under Various Loading Protocols

Abstract

This paper presents full-scale experimental tests on the seismic behavior of a stone curtain wall system with undercut bolt anchorage (SCWS-UBA). Experimental set-ups were developed to test full-scale stone curtain wall systems subjected to three loading protocols: quasi-static in-plane loading, dynamic in-plane loading, and dynamic coupled in-plane and out-of-plane loading. In all three tests, the SCWS-UBA failed due to connector disengagement, followed by fracture of silicone sealant and transom-to-mullion connection welds and, finally, the falling out of stone panels. The SCWS-UBA specimens exhibited a large displacement capacity with an ultimate falling-out drift exceeding 3.0% in all tests. The drift ratio at connector disengagement was almost identical for both quasi-static and dynamic in-plane loading scenarios, indicating that in-plane accelerations had a minimal impact on stone curtain wall failure. In addition, disengagement of the connector was dependent on the horizontal edge distance and vertical overlap depth between the connector and the L-shaped steel angle. Simplified formulas for calculating the horizontal and vertical displacement of the connector were then developed. Based on these, seismic design recommendations were proposed for the overlap depth and edge distance between the connector and L-shaped steel angle, thereby preventing the falling out of stone panels.