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论文类型：期刊论文

发表时间：2012-02-25

发表刊物：STRUCTURAL ENGINEERING AND MECHANICS

收录刊物：SCIE、EI、Scopus

卷号：41

期号：4

页面范围：495-508

ISSN号：1225-4568

关键字：lightweight aggregate (LWA) concrete; Unified Twin-Shear Strength (UTSS) theory; multi-axial strength criterion; ultimate strength envelope; tensile and compressive meridians

摘要：The strength theory of concrete is significant to structure design and nonlinear finite element analysis of concrete structures because concrete utilized in engineering is usually subject to the action of multi-axial stress. Experimental results have revealed that lightweight aggregate (LWA) concrete exhibits plastic flow plateau under high compressive stress and most of the lightweight aggregates are crushed at this stage. For the purpose of safety, therefore, in the practical application the strength of LWA concrete at the plastic flow plateau stage should be regarded as the ultimate strength under multi-axial compressive stress state. With consideration of the strength criterion, the ultimate strength surface of LWA concrete under multi-axial stress intersects with the hydrostatic stress axis at two different points, which is completely different from that of the normal weight concrete as that the ultimate strength surface is open-ended. As a result, the strength criteria aimed at normal weight concrete do not fit LWA concrete. In the present paper, a multi-axial strength criterion for LWA concrete is proposed based on the Unified Twin-Shear Strength (UTSS) theory developed by Prof Yu (Yu et al. 1992), which takes into account the above strength characteristics of LWA under high compressive stress level. In this strength criterion model, the tensile and compressive meridians as well as the ultimate strength envelopes in deviatoric plane under different hydrostatic stress are established just in terms of a few characteristic stress states, i.e., the uniaxial tensile strength f(t), the uniaxial compressive strength f(c), and the equibiaxial compressive f(bc). The developed model was confirmed to agree well with experimental data under different stress ratios of LWA concrete.