ANALYSIS OF REINFORCED CONCRETE HOLLOW （分析钢筋混凝土空心）.PDFVIP

th The 14 World Conference on Earthquake Engineering October 12-17, 2008, Beijing, China ANALYSIS OF REINFORCED CONCRETE HOLLOW PIERS BEHAVIOR: BENEFITS OF FRP CONFINEMENT. 1 2 3 4 G.P. Lignola , A. Prota , G. Manfredi and E. Cosenza 1 Assistant Professor, Dept. of Structural Engineering , University of Naples “Federico II”, Naples, Italy 2 Assistant Professor, Dept. of Structural Engineering , University of Naples “Federico II”, Naples, Italy 3 Professor, Dept. of Structural Engineering , University of Naples “Federico II”, Naples, Italy 4 Professor, Dept. of Structural Engineering , University of Naples “Federico II”, Naples, Italy Email: glignola@unina.it, aprota@unina.it, gamanfre@unina.it, cosenza@unina.it ABSTRACT : Reliable stress-strain behavior of concrete is necessary particularly when a member is subjected to combined bending and axial load and confinement effects should be accounted for. A unified theory for confinement of circular hollow sections is proposed herein, that can be extended to the case of solid and noncircular sections. The main aim of the model is to trace step-by-step the evolution of the three dimensional stresses in confined concrete and confining devices (i.e. FRP externally bonded jackets). The iterative model is able to estimate confinement effectiveness and to plot stress-strain relationships, which are different in the case of solid and hollow sections. Through the proposed improved model, a simplified closed form solution has been also derived to directly determine ultimate confined concrete properties and stress