Ricardo O. Foschi

Modeling Hysteretic Behavior of Wood Shear Walls with a Protocol-Independent Nail Connection Algorithm

This paper presents an extension to an algorithm called HYST to develop the hysteresis characteristics of a nail connection. The paper also discusses the implementation of the algorithm in a finite-element model of a wood shear wall, called WALL2D, to study the hysteretic wall response. The HYST algorithm is a protocol-independent and mechanics-based procedure that considers the nail shank as steel beam elements and the wood embedment medium as compression-only spring elements smeared along the nail shank. By accounting for the stiffness degradation of the wood embedment medium under cyclic loading, HYST can fully address strength/stiffness degradation and the pinching effect in the hysteresis of typical nail connections. HYST was verified by the load-slip hystereses from nail connections tested with two different loading protocols. The WALL2D application model consists of linear elastic beam elements for framing members, orthotropic plate elements for sheathing panels, linear springs for framing connecti...

Seismic Reliability Analysis of Diagonal-Braced and Structural-Panel-Sheathed Wood Shear Walls

Reliability-based assessment of seismic performance of wood shear walls needs to consider many uncertainties arising from earthquake ground motions, material properties, carried mass, and analytical models. Using a response surface method with importance sampling, this paper presents a seismic reliability analysis on eight types of diagonal-braced and structural-panel-sheathed shear walls which are commonly used in modern post-and-beam wood buildings. A recently developed wood shear wall model was used to simulate the seismic response of the shear walls. The shear wall model parameters were calibrated and verified using a reversed cyclic test database. Peak wall drift was chosen as the performance criteria to estimate the failure probabilities of the walls with respect to two performance expectations. The results presented herein showed that the seismic reliability of the structural-panel-sheathed walls was higher than that of the diagonal-braced walls.

Modeling Load-Displacement Hysteresis Relationship of a Single-Shear Nail Connection

AbstractA finite element based single-shear nail-connection model has been developed based on an existing computer model which idealizes dowel-type wood connection as an elastoplastic beam surround...