The L-shaped and T-shaped section columns are commonly found in the corners and the edges of the buildings. Compared with the conventional rectangular column, these kinds of columns have advantages of optimizing the structure strength and making better use of the living space. Particularly in Taiwanese street houses, L- and T-shaped columns can be constructed on the first floor to provide a better seismic resistance and prevent the soft-story mechanism along the weak direction of the building.
In this study, ten specimens including four L-shaped columns and six T-shaped columns were tested under combined axial and cyclic loading. An innovative method was proposed to retrofit the conventional rectangular columns into L- and T-shaped columns. The seismic performance of the columns was investigated in term of failure mechanism, crack patterns, hysteric response, strain of reinforcement, energy dissipation and displacement composition. The test results featured that the L- and T-shaped column possessed a good seismic capacity with an adequate lateral strength and significant ductility. The shear behavior of L- and T-shaped column were also studied by the shear failure of three specimens.
An evaluation of the lateral strength of L- and T-shaped monolithic and retrofitted columns was conducted using the current design code. The results highlighted that the code P-M interaction analysis method could satisfactorily estimate the nominal moment and maximum probable moment could be conservatively estimated by 1.3 times of the nominal moment.
A pushover analysis was proposed. The analytical results were well matched with test results in term of initial stiffness and maximum lateral force; however, the drifts estimation was not very accurate, especially for the shear critical columns.

ABSTRACT
ACKNOWLEDGEMENT
TABLE OF CONTENTS
LIST OF FIGURES
LIST OF TABLES
LIST OF NOTATIONS
Chapter 1. INTRODUCTION
1.1 Background
1.2 Objectives and Scope
1.3 Outline 17
Chapter 2. LITERATURE REVIEW
2.1 Material modelling
2.2 Pushover analysis
2.3 Shear reinforcement requirements
2.4 Shear strength calculation
2.5 Review previous research
Chapter 3. EXPERIMENTAL PROGRAM
3.1 Specimens design
3.2 Specimens preparation
3.3 Materials
3.4 Retrofitting methodology
3.5 Test setup
Chapter 4. TEST RESULTS
4.1 Test observations
4.2 Compare test results
4.3 Strain gauges reading
4.4 Energy dissipation and displacement composition
4.5 Analysis
Chapter 5. CONCLUSIONS
REFERENCES
APPENDIX A – CRACK PATTERNS
APPENDIX B – STRAIN READING
APPENDIX C – RESULTS OF TENSILE STRENGTH TEST

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