Using Viscoelastic Material to Reduce the Dynamic Response of Woodframe Structures

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Abstract The objective of the proposed research is to develop an advanced panel system for improving the seismic performance of wood frame structures using thin laminates of viscoelastic (VE) damping materials. The VE will be integrated into the lateral load resisting system of the structure material between the wall frame and the sheathing and/or finishing material. It is anticipated that the final panel system will utilize little to no fasteners to connect the sheathing and drywall to the stud frame and provide increased durability at significant cost savings. VE material is self-adhesive and comes in rolls (similar to tape). The material is readily available, very flexible, easy to apply, and can be layered. The results of one preliminary full-scale test of one thin layer (0.005") of the material applied to a wall show that significant improvements can be realized without affecting the overall wall dimensions. Innovative applications of viscoelastic sheet material may potentially have a profound impact on the design, construction and rehabilitation of wood frame structures. The proposed research program will test and evaluate the application of viscoelastic material in wood frame structures, typical of residential housing, for improving the seismic performance and durability of the structure. An experimental program has been proposed to evaluate the application of VE material to wood frame construction at the connection/component level. A non-linear finite element model will be used to conduct parametric studies to optimize the placement of the VE material within the wall. The model can account for the supplemental damping and stiffness of the VE material and will be used to predict the full-scale wall behavior. Baseline full-scale tests (static and cyclic) will be conducted on conventional walls with and without drywall. Based on the connection and analytical work, an optimal design will be determined and full-scale wall tests will be conducted on walls with and without drywall and compared to the analytical results. The research proposed reduces the risk of life, injury, and property destruction and improves durability by developing a state-of-the-art shearwall panel system. Wood frame structures continue to experience significant structural and non-structural damage during moderate to large earthquakes. In many cases the structure may remain standing after the disaster, only for there to be serious non-structural damage that renders the residence uninhabitable. Having just high ductility is no longer satisfactory; today's structures must be engineered and designed to perform better and to insure more than just life safety. Increasing the energy dissipation capacity of the primary lateral load resisting system of the structure would significantly reduce the risk to loss of life, injury and non-structural damage during seismic events. The concept proposed makes use of existing materials and incorporates them into the structure in such as way as to not disrupt the design of the wood frame shear wall and simplifies the construction process.