9810005 Hajjar This project presents a combined computational/experimental effort focusing on the seismic behavior of the interface between concrete walls and steel frame members in composite wall structural building systems. The work targets the development of comprehensive, nonlinear, static and dynamic analysis procedures for modeling composite wall building structures, including the behavior of the steel/concrete interface; and achieving a more through understanding of the composite cyclic interaction between RC walls and steel framing. Composite structural wall systems provide excellent strength and stiffness to withstand both service level drift and ultimate forces from seismic events. The objectives of the research include the development of a finite element formulation for the seismic analysis of composite reinforced concrete walls with surrounding steel framing, the quantification through experimental testing of the combined cyclic shear and tensil strength of headed hear studs and deformed bar anchors embedded in concrete panels, and the verification and calibration of the shear and axil strength interaction relations under monotonic and cyclic loading for connectors used in practice used in practice. A three-dimensional, nonlinear finite element to model to simulate the cyclic interaction at the steel/concrete wall interface will be formulates. A series of experiments will be designed to document the cyclic interaction along the interface between RC walls and surrounding steel framing. The analyses will feature a geometrically and materially nonlinear finite element formulation, using a new fiber-based finite element for the shear connectors and appropriate continuum elements for the concrete in the interface region, align with stress-space plasticity formulations for both the concrete and steel. The ultimate goals is the development of clear guidelines for: 1) incorporating the steel-concrete interface behavior in both linear and nonlinea r analyses of composite wall systems; and 2) detailing the steel frame-concrete panel connection to achieve desirable performance goals. This project is supported under the fourth year competition of NSF 94-154. ***
