Numerical and Experimental Investigations of the Seismic Response of Light-Frame Wood Structures

Download or read book Numerical and Experimental Investigations of the Seismic Response of Light-Frame Wood Structures written by Ioannis Christovasilis and published by . This book was released on 2011 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: In support of the performance-based seismic design procedures for light-frame wood structures, developed within the NSF-funded NEESWood Project, a dual study with experimental and analytical components was conducted. In the context of the experimental investigation, a full-scale, two-story, light-frame wood townhouse building was tested on the twin relocatable tri-axial shake tables operating in unison, at the University at Buffalo UB-NEES site. The test structure performed well under the Design (DE) and Maximum (MCE) levels of shaking and the experimental results demonstrated the beneficial effect of wall-finishes on improving its seismic response. The analytical task focused on the development, implementation and validation of a novel numerical framework, suitable for nonlinear inelastic, static and dynamic two-dimensional (2D) analysis of light-frame wood structures.^The 2D building model is based on a sub-structuring approach that considers each floor diaphragm as rigid body with three kinematic, and potentially dynamic, degrees-of-freedom and a sub-structure model is developed for each individual single-story wall assembly that interacts with the adjacent diaphragms and generates the resisting quasi-static internal forces. The 2D shear wall model takes explicit consideration of all sheathing-to-framing connections and offers the option to simulate deformations in the framing members and contact/separation phenomena between framing members and diaphragms, as well as any anchoring equipment (i.e. anchor bolts, holdown devices), typically installed in light-frame shear walls to develop a vertical load path that resists overturning moments.^Corotational descriptions are used to solve for displacement fields that satisfy the equilibrium equations in the deformed configuration, accounting for geometric nonlinearity (large rotations - small deformations) and P-Delta effects. These attributes result in a nonlinear element capable of capturing the lateral response of shear walls up to their complete failure and, thus, the side-sway collapse of the structure. To validate the proposed numerical framework, a number of simulation examples are presented, based on existing experimental results from pseudo-static tests of single- and two-story full-scale shear wall specimens, as well as unidirectional shake-table tests of a symmetric single-story full-scale structure.