Experimental Study on Flexural Behavior of Reinforced Concrete Walls
Sergio Sunley*1, Koichi Kusunoki*2, Taiki Saito*3,
and Carlos Zavala*4
*1Universidad Centroamericana José Simeón Cañas (UCA), PO 01-168, San Salvador, El Salvador, Centro América
*2Yokohama National University, 79-5 Tokiwadai, Hodogaya ku, Yokohama City, Kanagawa 240-8501, Japan
*3Department of Architecture and Civil Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580, Japan
*4Faculty of Civil Engineering, CISMID, National University of Engineering (UNI), Av. Tupac Amaru, 1150 Rimac, Lima 25, Peru
Design codes prescribe equations for the ultimate state design of RC walls with flange walls as boundary elements. These codes consider part of the length of the flange wall as a width that will effectively resist lateral loads. However, wall damage and the accuracy of the effective width used in the calculations have not been sufficiently discussed. Therefore, a loading test is carried out at Yokohama National University on two 1/3 scale specimens in order to evaluate the strength, damage, energy dissipation, and behavior of RC structural walls in flexure. One specimen without flange walls and one with flange walls are tested. The strength and response of each specimen are described, and the prediction accuracy of the design flexural strengths given by design codes ACI, Eurocode, and AIJ are examined. Experimental strain data are used to describe the behavior of the flange wall in order to understand the mechanism and to confirm the accuracy of the effective width prescribed by the design codes in terms of tension and compression. The result of the experimental study reveals that design prescriptions given by ACI, Eurocode, and AIJ guidelines can conservatively estimate the flexural strength for RC walls without flanges, but they underestimate the flexural strength for flanged walls. This underestimation is due to a lack of knowledge of the mechanism that develops at the flange. It is not possible to determine a specific value for flexural effective width. However, according to the results of calculations, a portion larger than the width proposed by the aforementioned design codes serves to resist the stresses imposed by lateral loads. Therefore, it is confirmed that the flange width is underestimated by the design codes, and it increases with the imposed drift level. The stress distribution at the flange in the out-of-plane direction is found not to be uniform, a fact that is at odds with design assumptions.
-  S. Wood, J. Wight, and J. Moehle, “The 1985 Chile earthquake Observations on Earthquake Resistant construction in Vi��na del mar,” A Report to the National Science Foundation Research grants ECE 86-03789, ECE 86-03264 and ECE 86-06089, Department of civil engineering university of Illinois at Urbana Champaign, Urbana, Illinois, February 1987.
-  Architectural Institute of Japan, “Guidelines for Performance Evaluation of Earthquake Resistant Reinforced Concrete Buildings,” 2005.
-  American Concrete Institute, “Building Code Requirements for Structural Concrete and Commentary,” ACI 318-08, 2008.
-  European Committee for Standardization, “Eurocode 2: Design of Concrete Structures, Part 1: General Rules and Rules for Buildings,” EN 1992-1-1:2004 (E), Revised final draft, Brussels, Belgium, December 2003.
-  J. W. Wallace, “Evaluation of UBC-94 Provisions for Seismic Design of RC Structural Walls,” Earthquake Spectra, Vol.12, No.2, pp. 327-348, May 1996.
-  European Committee for Standardization, “Eurocode 8: Design of structures for earthquake resistance – Part 1: General Rules seismic actions and rules for buildings,” EN 1998-1:2004 (E), Brussels, Belgium, December 2003.
-  A. Shibata, “Dynamic Analysis of Earthquake Resistant Structures,” Tohoku University Press, Sendai, 2010.