A performance-based approach to retrofitting unreinforced masonry structures for seismic loads

The structural inadequacy of existing unreinforced masonry (URM) buildings to resist possible seismic loading is a serious problem in many parts of the United States, including the Northeast and Midwest. The fact that many of these buildings are deemed historic structures or house critical facilities, like firehouses, emphasizes the need for an effective retrofitting program. The Federal Emergency Management Agency published a performance-based design code FEMA 356 in 2000 to use for analyzing and retrofitting existing structures. This code includes procedures for URM buildings. This paper applies these performance-based analysis procedures to a URM shear wall and compares the results to a modified analysis proposed by researchers. The wall is then rehabilitated using two common retrofit methods and again analyzed using the code. Recommendations are made for practicing engineers when evaluating URM structures for seismic loads. Thesis Supervisor: Jerome J. Connor Title: Professor, Civil and Environmental Engineering TABLE OF CONTENTS

[1]  Luciano Galano,et al.  Performance Of Distributed Base Isolation System For Masonry Buildings , 2001 .

[2]  Nelson Lam,et al.  EXPERIMENTAL INVESTIGATION OF UNREINFORCED BRICK MASONRY WALLS IN FLEXURE , 2004 .

[3]  Pierino Lestuzzi,et al.  In-Plane Seismic Response of URM Walls Upgraded with FRP , 2005 .

[4]  Daniel P. Abrams,et al.  Effectiveness of rehabilitation on seismic behavior of masonry piers , 2007 .

[5]  P. Lestuzzi,et al.  STATIC CYCLIC RESPONSE OF MASONRY WALLS RETROFITTED WITH FIBER-REINFORCED POLYMERS , 2007 .

[6]  Roberto T. Leon,et al.  Analyses of a Two-Story Unreinforced Masonry Building , 2006 .

[7]  Michel Bruneau,et al.  Seismic Testing of Repaired Unreinforced Masonry Building having Flexible Diaphragm , 2004 .

[8]  Michel Bruneau,et al.  Analysis and Design of Low-Rise Masonry and Concrete Walls Retrofitted Using Steel Strips , 2000 .

[9]  Roberto T. Leon,et al.  Lateral Load Tests on a Two-Story Unreinforced Masonry Building , 2006 .

[10]  Robert G. Drysdale,et al.  Rehabilitation of Masonry Walls using Unobtrusive FRP Techniques for Enhanced Out-of-Plane Seismic Resistance , 2006 .

[11]  Robert G. Drysdale,et al.  Load-Displacement of Masonry Panels with Unbonded and Intermittently Bonded FRP. II: Analytical Study , 2007 .

[12]  M. Elgaaly,et al.  Behavior of Composite Unreinforced Masonry–Fiber-Reinforced Polymer Wall Assemblages Under In-Plane Loading , 2005 .

[13]  Roberto T. Leon,et al.  Recommendations for Seismic Evaluation and Retrofit of Low-Rise URM Structures , 2006 .

[14]  Ahmed Ghobarah,et al.  Out-of-Plane Strengthening of Unreinforced Masonry Walls with Openings , 2004 .