Nonductile reinforced concrete moment-resisting frames constructed twenty or more years ago have been indentified as one of the most pressing problems associated with mitigating hazards in the existing building inventory. During the past six years a variety of repair and strengthening techniques for reinforced concrete frames have been investigated and includes addition of structural walls, jacketing or enlarging columns and/or beams, and addition of steel bracing. This research program extends previous work conducted at the University of Texas. The program consists of frame tests as well as tests on critical details of strengthening procedures for nonductile moment-resisting frames. The project is divided into two major tasks: (1) Problems associated with addition of structural walls to nonductile frames, including improvement of column splice performance, study of interface flaws at top of wall, interface shear transfer tests (influence of axial load and dowels), and frame tests with infill walls; and (2) Addition of steel bracing systems to reinforced concrete frames including detailing of connections for continuity, systems with braces having high slenderness ratios, and systems with braces having low slenderness ratios. This is a collaborative research project between the University of Texas at Austin and H. J. Degenkolb Associates. This research project represents the participation by the University of Texas.
