Dec 102006
 
Authors: Emily Lance

An 1,800 square foot, 40-ton home in Buffalo, N.Y., violently shook, the victim of a simulated 6.7 magnitude earthquake.

The three-bedroom, two-bathroom home was the largest wood structure ever to be tested for how it would fare during an earthquake – and CSU researchers have now begun a six-month data-analyzing process.

The test, performed at the University of Buffalo structural engineering and earthquake engineering laboratory, featured full-scale ground motions in three directions (triaxial motions), a feature most earthquake tests lack.

The simulation was similar to the 1994 Los Angeles-area quake.

Sensors were installed inside the house to gather information about how each component of the building behaves. They’re connected by cyber grid, allowing data to be viewed by the public within five months.

This four-year, five-university NEESWood project is designed to provide engineers with data about how to improve performance of wood frame structures during earthquakes.

Two students and one professor do tests and designs for larger wood structures that can survive earthquakes and improve earthquake monitoring from the University of Buffalo, Texas A&M, Cornell University and Rensselear Polytechnic Institute (RPI).

John van de Lindt, associate professor in civil engineering, is the lead supervisor in the CSU NEESWood project.

“The final product is to develop a new design concept,” van de Lindt said.

The main goal was to get a baseline for computer modeling, taking a step closer to the ultimate goal of the four-year project to reduce annual financial loss for wood frame structures and enable taller structures during an earthquake.

The NEESWood project is funded by Congress, and CSU received more than $1.24 million for the study.

To use the money more efficiently, the team is working on a software project to simulate the potential movement of a building during an earthquake without the use of a very costly shake table test.

SAPWood, a software program designed to model the behavior of a wood frame structure, can simulate a non-linear, three-dimensional view of the building as it moves.

Shiling Pei, graduate research assistant, is one of the primary SAPWood software developers on the project.

“To simulate the action of a two-story building is not fundamentally different than that of a six story building,” Pei said.

CSU has been conducting tests on the university’s shake table, an earthquake simulator made from pieces of steel set on beams with hydraulic actuators below them moving horizontally to simulate the movement of an earthquake.

A metal structure attached to the ceiling can be set on top of a two-story structure to model a third floor.

Van de Lindt describes using the shake table as similar to using an amp with an electric guitar. About 10 to 20 gauges are used to tune and tweak the action of the table.

Hongyan Liu, graduate research assistant in structural analysis and design, will be taught how to operate the shake table in the spring.

Lui is researching the comparison on the “effects of the base insulation with a building that has none,” which is an additional study for the NEESWood project.

Future tasks also include a 2007 spring test on a wood frame during a hurricane and the 2009 NEESWood project culmination of a six-story building test in Miki City, Japan, on the world’s largest shake table.

Staff writer Emily Lance can be reached at campus@collegian.com.

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