University of Alabama (UA) researchers are leading an effort to develop taller, sturdier wood-framed buildings in earthquake-prone areas.
Dr. Thang Dao, UA assistant professor of civil, construction and environmental engineering, hopes to combine two methods of constructing tall wood buildings to yield a new system that could lead to wood-framed buildings of eight to 12 stories that withstand earthquakes better than current methods, which top out at seven stories.
The research team, which also includes Dr. Sriram Aaleti, UA assistant professor of civil, construction and environmental engineering, and Dr. John van de Lindt, professor of civil and environmental engineering at Colorado State University, will study how to combine the traditional light wood frame system (LiFS) of construction with the emerging method of cross-laminated timber (CLT), an engineered wood panel typically comprising layers of wood glued at intersecting angles. CLT is strong and it can resist lateral forces that are created during an earthquake.
In the proposed system, the CLT panel anchored with unbonded post-tensioning will be combined with the LiFS. While the unbonded post-tensioning in the CLT will self-center the system, the connections in the light-frame wood should provide a way to dissipate the energy created during an earthquake. The system will be designed to ensure that a building’s main structural parts remain elastic and undamaged during an earthquake.
“The endeavor of this research project is to understand the mechanistic and statistical properties of all sub-components of the CLT-LiFS system and form a fundamental understanding of how to combine these two types of systems into an optimal hybrid system,” Dao says.
The research project, sponsored by the National Science Foundation, will use equipment in the Large Scale Structures Lab at UA to mimic earthquakes on partially built structures connected to computer simulations that give feedback on how the entire building would perform.
According to Dao, the research is motivated by population growth and urban densification, which have necessitated taller, sustainable buildings that perform better in moderate to large earthquakes. “It is critical that such buildings have minimal interruption to allow people to remain in their residences and community following an [earthquake],” he says.