Energy-dissipating polymer matrix composite-infill wall system for seismic retrofitting

Polymer matrix composite (PMC)-infill walls hold great promise for energy dissipation when used in retrofitting applications where seismic activity is a consideration. This paper presents the analysis, design, and testing of PMC-infill walls developed for seismic retrofitting applications. The PMC-infill wall system consists of two fiber-reinforced polymer laminates with an infill of vinyl sheet foam. At the interface between the laminates, viscoelastic honeycomb is used to dissipate energy and improve the damping characteristics of the structure. As part of this research, analytical and experimental studies were performed to explore the effectiveness of this seismic retrofitting strategy and to examine the behavior of the PMC-infill wall system when subjected to monotonic and cyclic loading. A steel frame retrofitted with a PMC-infill wall was monitored to assess the resultant enhancements to its seismic-energy resistance capacity. In testing the PMC-infill wall system in this research, a large-scale steel frame was used to avoid the typical uncertainties associated with scaling the dimensions. The optimal design for the stacking sequence of a PMC-infill wall panel was determined based on the performance and material cost using the finite-element analysis. Finally, the observed behavior of the PMC-infilled frame was assessed on the bases of stiffness, strength, modes of failure, and energy dissipation output. The experimental and analytical studies demonstrate that the introduction of a PMC-infill wall panel in a semirigidly connected steel frame produces significant enhancements to stiffness, strength, and energy dissipation.