Cargo container research to improve buildings' ability to withstand tsunamis
Washington, Feb 6 : Researchers are working on methods to improve the designs of buildings in areas that are vulnerable to tsunamis, according to a report.
Ronald Riggs, a structural engineer at the University of Hawaii, first began thinking about the problem that emerge due to poor building structures as he examined damage to bridges and buildings following Hurricane Katrina.
He noticed the cargo containers and barges that had been flung onto land in areas such as Biloxi, Miss. On another scientific excursion to Samoa, he says he saw a shipping container "whacked against a meeting hall and there was no port anywhere nearby."
His colleagues and he proposed research to analyze several pieces of the puzzle with the help of the George E. Brown Jr. Network for Earthquake Engineering Simulation (NEES), a distributed laboratory with 14 sites across the country.
For Riggs, two NEES sites were needed. One is at Lehigh University in Bethlehem, which specializes in real-time multi-directional testing for earthquake simulation of large-scale structural systems, and the other is a wave flume longer than a football field at the Tsunami Research Facility at Oregon State University.
At the Lehigh site, they swung full-scale wooden poles and shipping containers through the air on a pendulum to determine the force of impact at various velocities, and at Oregon State, they ran similar tests at a 1:5 scale, but this time in its large flume wave to see if that made a difference.
According to the report, his basic assumptions held true, but there were two surprises.
First, when the speed of the projectile was the same, the water did not have a significant impact, and the second that the weight of the shipping container's contents also did not matter as much as he would have expected.
The container itself, which is roughly 20 feet long and weighs about 5,000 pounds empty, could weigh as much as 60,000 pounds when fully loaded. Yet, its load when striking a building was not significantly greater than that of the empty container.
According to Riggs, the reason is the same as for the water.
The next step for Riggs and his team is to use the preliminary findings to better define building guidelines and policy.