American Society of Civil Engineers


Evaluation of a Sprayable, Ductile Cement-Based Composite for the Seismic Retrofit of Unreinforced Masonry Infills


by Sarah L. Billington, (Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305-4020 E-mail: billington@stanford.edu), Marios A. Kyriakides, (Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305-4020), Ben Blackard, (Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, CO 80202-0428), Kaspar Willam, (Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, CO 80202-0428 E-mail: willam@colorado.edu), Andreas Stavridis, (Department of Structural Engineering, University of California, San Diego, CA 92093-0085), and P. Benson Shing, (Department of Structural Engineering, University of California, San Diego, CA 92093-0085 E-mail: pshing@ucsd.edu)
Section: Innovative Approaches to Rehabilitation 1, pp. 823-834, (doi:  http://dx.doi.org/10.1061/41084(364)75)

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Document type: Conference Proceeding Paper
Part of: Improving the Seismic Performance of Existing Buildings and Other Structures
Abstract: A new retrofit technique for unreinforced masonry infills in non-ductile reinforced concrete frame structures is being investigated. The proposed technique uses a thin layer of sprayable, ductile fiber-reinforced mortar material referred to as Engineered Cementitious Composites, or ECC. The aim of the retrofit is to hold the masonry wall together to delay infill and frame strength degradation and enhance system ductility. Proof-of-concept experiments on retrofitted masonry prisms and beams demonstrated large increases in strength and ductility. Quasi-static, in-plane, cyclic testing of small-scale frames with masonry infills including 3 retrofit designs demonstrated a 10x increase in ductility in one design relative to the unretrofitted system. Results were used to design a retrofit for a 2/3-scale, in-plane test, where a 2.6 x increase in ductility was achieved. Several finite element modeling approaches are under investigation for use in system predictions and further retrofit analyses.


ASCE Subject Headings:
Ductility
Cement
Seismic effects
Rehabilitation
Masonry
Fills