Damage and Residual Seismic Performance Evaluation of Reinforced Concrete Shear Walls


Abstract eng:
A shear wall is an effective earthquake resistant element in a reinforced concrete structure with its high stiffness and shear strength. Therefore, shear walls are widely used for reinforced concrete building structures in Japan. Once an earthquake occurs, initial damage such as cracks tends to appear in shear walls because of higher stiffness. In general, cracks are observed from the early stage of lateral loading in a experiment of reinforce concrete structures thus cracks in concrete do not directly correspond to deterioration of seismic performance if sufficient reinforcement are provided. However, ordinary people such as building owners and users generally considered cracks as damage and decrease of structural performance. Therefore, it is important to correlate damage level with deterioration rate of performance in reinforced concrete structures and develop a methodology to evaluate residual seismic capacity in order to explain clearly damage level to ordinary people. Guideline for post-EQ Damage Evaluation is published in Japan and a damage evaluation method is proposed[1]. In the Guideline, damage levels of structural elements are classified into five classes (I,II,III,IV,V). Seismic capacity reduction factor for each damage class are given by which residual seismic performance can be calculated. However, most of previous experimental data used in the Guideline are derived from loading test of structural elements of frame structure without shear walls such as beams and columns. From these back ground, static loading tests of shear walls are conducted in this paper. Five shear wall specimens are tested. The test parameter is damage level (damage class) of shear walls. Namely, different levels of damage was induced to four specimens(I,II,III,IV) by “pre-loading”. Meanwhile, one specimen is tested without pre-loading. Degradation in lateral strengths, ductility, stiffness and energy dissipation capacity of damaged shear walls are focused on as main parameter for residual seismic performance, and studied through comparison with undamaged specimen. Damage situation such as crack width and bar yielding is observed during the test and relation with their residual seismic performance is investigated. From experiment result, it was found that damage level in shear wall does not strongly influence the performance at the ultimate state, such as maximum shear force, deformation and energy dissipation capacities. On the other hand, in the state of the deformation experienced in preloading, the stiffness degraded. FEM analysis evaluated well the performance such as shear strength and ultimate deformation for not only undamaged but also damaged specimens except equivalent stiffness during pre-loading range in heavily damaged specimens that has experienced large deformation such as 6/1000rad.

Contributors:
Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
Rights:
Text je chráněný podle autorského zákona č. 121/2000 Sb.



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 Record created 2017-01-18, last modified 2017-01-18


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