Mass timber is an attractive and sustainable alternative structural engineering material to concrete and steel. Despite successful midrise to high-rise timber building projects around the world, such buildings have not been implemented in regions with high seismicity due in part to a lack of research and development on appropriate ductile seismic load resisting systems for heavy timber construction. This paper describes experiments conducted to develop a resilient lateral force-resisting wall system that combines cross-laminated timber (CLT) panels with vertical posttensioning (PT) to provide postevent recentering. Supplemental mild steel U-shaped flexural plate (UFPs) are intended to yield under cyclic loading while the PT and CLT components remain undamaged until large interstory drifts are experienced by the wall. The experiments were designed to explore various limit states for self-centering CLT (SC-CLT) walls, including their dependence on design variables and their effect on performance, and to investigate strength and stiffness degradation at large interstory drifts. It was found that the SC-CLT walls were able to recenter even after large drift cycles and the crushing of the CLT material was the governing limit state for most specimens. A hierarchy of desirable limit states was identified consisting of UFP yielding, CLT splitting, PT yielding, and CLT crushing.

The majority of buildings and the vast majority of residential structures in North America are constructed using light-frame wood. Many of these structures are subjected to high winds along the eastern seaboard and gulf coast, and as a result routinely suffer damage resulting in financial losses. A relatively new paradigm in the field of earthquake engineering is performance-based design. This paper presents the concept of performance-based wind engineering for wood-frame buildings through the development and application of fragilities to form different owner/user performance expectations, namely, occupant comfort, continued occupancy, life safety, and structural integrity. The approach includes the development and application of fragility curves. An example analysis and design for a simple light-frame wood building for all four performance expectations is presented. The final design of the building needed to achieve the specified levels of structural performance are discussed for each performance expecta...

The costliest natural disaster in U.S. history was Hurricane Katrina, which made landfall on August 29, 2005 at 7:10 a.m. EDT (6:10 CDT, local time) in Plaquemines Parrish, La. Tragically, Katrina caused widespread damage and loss of life but also provided an opportunity to collect data on wood-frame construction which will be useful for design engineers and building code officials in order to design safer and stronger buildings in the future. The objective of this study was to gather and process perishable wind damage data on residential wood-frame structures in nonflooded regions of Mississippi that can be used by the research and design code development community to improve the performance of wood-frame structures to strong wind loading. This study consisted of 3 days of data acquisition of wind damage to wood-frame structures along the U.S. Gulf Coast and was funded by the National Science Foundation. A total of 27 case studies, ranging from entire subdivisions to individual wood-frame structures, wer...

A cross-laminated timber (CLT) panel is a heavy timber structural component fabricated by laminating layers of timber boards in an orthogonal pattern. This paper presents a study of the lateral-load response of self-centering (SC) posttensioned CLT structural walls (i.e., SC-CLT walls), which are constructed by posttensioning CLT wall panels to the foundation with vertical posttensioning steel bars. The bars pass through the CLT panels and are anchored to the CLT panels at the top of the wall and to the foundation at the bottom of the wall. Cyclic loading tests were conducted on a series of SC-CLT wall specimens with different configurations. Structural limit states of SC-CLT walls under lateral load are identified. Two types of analytical models are proposed to predict SC-CLT wall response, namely, a design-oriented analytical model based on simple mathematical expressions, and a fiber-element-based numerical model. Comparisons between the analytical and experimental results are made, which indicate that the simple mathematical expressions and the fiber-element-based numerical model provide accurate estimates of the lateral-load response of SC-CLT walls under cyclic loading.

Floods can be devastating to communities and result in fatalities and injuries, negatively impacting the economy, and quality of life. This paper presents a review of community resilience research with a focus on flood hazard including recent advances in flood risk quantification methods and trends to integrate socio-economic factors. The focus of this review was placed on flood risk components including hazard, exposure, and vulnerability to move the current research from deterministic to probabilistic approaches in order to propagate uncertainties through flood modeling, damage, loss, and recovery. Both short-term and long-term impacts of different flood resilience measures are included. The largest gap identified in flood risk research was the need for a standardized quantitative assessment tool or framework that could measure the impact of approaches to improve resilience at the community level. That tool should include the interactions between the different community systems (physical infrastructure, economic systems, and social systems).

This paper presents a simplified direct displacement design (DDD) procedure which was used to design the shear walls for a six-story woodframe structure. The building was tested in the final phase of a Network for Earthquake Engineering Simulation (NEES) project. Specifically, NEESWood Capstone Building was designed to meet four performance expectations: damage limitation, life safety, far-field collapse prevention (CP), and near-fault CP. The performance expectations are defined in terms of combinations of interstory drift limits and prescribed seismic hazard levels associated with predefined nonexceedance probabilities. To verify that design requirements were met, a series of nonlinear time-history analyses (NLTHAs) was performed using suits of both far-field and near-fault ground motion records. The distributions of interstory drifts obtained from the NLTHA confirm that the Capstone Building designed using DDD meets all four target performance expectations, thereby validating the DDD procedure. Additio...