1 Associate Professor, Department of Architecture, National Cheng Kung University, Tainan, Taiwan, yhtu@mail.ncku.edu.tw
2 Master of Science, Department of Architecture, National Cheng Kung University, Taiwan
3 PhD Candidate, Department of Architecture, National Cheng Kung University, Taiwan
ABSTRACT
An analytical model for the seismic behavior of confined masonry (CM) wing-walls is proposed in this paper. CM wing-walls are the panel segments between openings and RC tie-columns. Based on the experimental results for seven full-scale CM wing-walls tested by the authors, the model describes a bilinear relationship of the load-displacement envelope curve. This paper focuses on the elastic section defined by the cracking load and displacement in the envelope curve and presents the rationale in setting up the analytical factors. The cracking load is estimated with the diagonal tension strength according to FEMA 356. The cracking displacement is estimated by considering CM wing-walls as diagonal compression struts. The compression strut analogy indicates that CM walls are subjected to additional axial compression induced by the lateral loading. Since axial stress plays an important part in the diagonal tension strength estimation, this paper proposes a method to derive the additional axial force from the lateral load. The distribution of lateral force between the masonry wall and tie-column is also examined, so the contribution of tie-columns can be included in the strength estimation. The proposed model has been validated with the experimental data. The model shows a conservative estimation for both cracking load and displacement, but the comparison with experimental load-displacement curves indicates a good fit.
KEYWORDS: confined masonry, seismic behavior, lateral strength, load-displacement relationship
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