The 14 th World Conference on Earthquake Engineering October 12-17, 2008, Beijing, China SEISMIC PERFORMANCE OF CLAY MASONRY VENEER H.O. Okail 1 , P.B. Shing 2 , R.E. Klingner 3 and W.M. McGinley 4 1 Graduate Research Assistant, Dept. of Structural Engineering, The University of California at San Diego, California, USA 2 Professor, Dept. of Structural Engineering, The University of California at San Diego, California, USA 3 Professor, Dept. of Structural Engineering, The University of Texas at Austin, Texas, USA 4 Professor, Dept. of Civil and Environmental Engineering, University of Louisville, Kentucky, USA Email: hokail@ucsd.edu, pshing@ucsd.edu, klingner@mail.utexas.edu, m.mcginley@louisville.edu ABSTRACT: This paper presents an experimental investigation of the out-of-plane seismic behavior of clay brick veneer over wood-stud walls. A series of shaking-table tests was performed on wall panels consisting of a clay brick wythe attached to a wood-stud frame with metal anchors. Different anchor types and spacings conforming to the current design standards in the US were used. Some walls had a window opening and some did not. The walls were tested to failure through shaking in the out-of-plane direction with increasing earthquake ground motion levels. This paper presents a summary of the experimental program and results, design implications, and an appraisal of the current code provisions. The test results indicate that the veneer walls could sustain ground motion levels considerably beyond the maximum considered earthquake. KEYWORDS: Seismic Performance, Shake Table, Brick Veneer, Veneer Anchors, Wood Frames. 1. INTRODUCTION Brick veneer is often found in low-rise residential and commercial constructions in many parts of the United States [1]. The system consists of a clay brick wythe backed by a wood-stud frame. The brick wall is connected to the backing through metal veneer anchors (also referred to as veneer ties) [2]. The ties span over an air gap (typically 25 or 50 mm), acting as a drainage cavity to allow the passage of the moisture out of the structure through weep holes located at the bottom brick course. A waterproof flashing is placed below the veneer wythe to prevent water permeation at the base [3]. As a non-structural component, a veneer is designed to support only its own weight and to transfer face loads, like wind- or earthquake-induced forces, to the backing system, which is normally part of the load-carrying system of the building [4]. Under earthquake loads, however, the veneer and the backing system will develop a composite action when the two are securely tied. The interaction of the two is influenced by their respective stiffness and inertial properties, and may result in significant tie forces. A veneer wall system can be subjected to both in-plane and out-of-plane loading. Veneer ties can be subjected to high demands of axial and shear forces depending on the direction of the earthquake excitation. Under a severe excitation, such systems can fail by fracture of the veneer at the mortar joints or by failure of the ties due to various causes. Under the auspices of the George E. Brown, Jr. Network for Earthquake Engineering Simulation Program (NEES) of the US National Science Foundation, a collaborative research project has been carried out to study the seismic performance of brick veneer and brick veneer anchors over wood-stud and masonry backing systems. This paper presents results from a study of the seismic performance of clay brick veneer backed by wood-stud walls. In this study, a set of experiments was conducted on single wall panels representative of typical sections of a one-story building. The walls were tested in their out-of-plane direction under increasing ground motion levels.