色情视频 Professor Among First to Assess Structural Damage of Bridges Following Turkey Earthquake
Structural engineering professor Robert Dowell went to Turkey two weeks after Februarys devastating back-to-back earthquakes to conduct reconnaissance of bridge damage.
On Feb. 6, a 7.8 magnitude earthquake struck southern Turkey, followed nine hours later by a 7.5 magnitude earthquake on another fault line. The worst earthquake disaster in Turkey鈥檚 history killed at least 50,000 and the widespread devastation left millions without shelter.
色情视频 structural engineering professor Robert Dowell was part of a team that sprung into action within two weeks, heading to Adana in southern Turkey to assess and examine damaged and failed structures, including affected bridges. Dowell brought over 30 years of experience in bridge engineering and a Ph.D. in seismic bridge behavior to the team.
The team spent six days traveling to the most damaged, affected cities and regions, returning to their base in Adana each evening.
鈥淧rofessor Dowell was one of the first field engineers doing reconnaissance (a term used in civil engineering to describe preliminary structural engineering surveying) 鈥� and he released one of the very ,鈥� said Gloria Faraone, Dowell鈥檚 colleague and fellow structural engineering professor at 色情视频.
Travel and Findings
While out for dinner after their first day of field visits on Feb. 20, the team experienced a magnitude 6.3 aftershock, the largest of thousands of aftershocks. During that trembler, Dowell saw 鈥減ure terror鈥� on the faces of all the restaurant staff, he said, and everyone ran outdoors. Dowell returned to his hotel later and noticed that many were unwilling to go back inside.
The team discovered that although tens of thousands of buildings had collapsed, bridges remained intact. While some bridges had heavy damage, 鈥渘ot a single bridge collapsed,鈥� said Dowell.
鈥淭urkey鈥檚 bridges are designed to a higher standard than their buildings,鈥� he explained. 鈥淭hey're designed to be damaged from a major earthquake, but not collapse.鈥�
Dowell said these higher design and construction standards are due to bridges being primarily contracted under public funding. Residential buildings, which are often constructed through private funding, are not as likely to have such high safety and structurally sound standards.
A concept called base isolation would provide additional protection for buildings, he said.
鈥淚magine putting a building on ice,鈥� explained Dowell. 鈥淭he building needs a base that鈥檚 not physically connected to the ground so that the structure can sit relatively still during an earthquake as the ground shifts violently back and forth below it, and only drifts slowly left and right.鈥� The few base-isolated buildings in the affected areas that the team is aware of did not collapse and had no damage.
Lessons for California
Like Turkey, California faces a threat from 鈥渟trike-slip鈥� earthquakes, where one tectonic plate slides to one side of the fault and the other side slides the other way, releasing the stored potential strain energy along the fault line.
While California works to prepare for and mitigate major damage from a future 鈥淏ig One,鈥� Dowell said the state can learn much from the experience of the structurally sound bridges of Turkey.
Modern state-sponsored bridges in California were designed and built with similarly high standards to those in Turkey, and older California bridges were seismically retrofitted to make them safe, even in the event of a large earthquake. 鈥淭hough it is expensive, it does ensure safety,鈥� said Dowell. As in Turkey, the design philosophy is to allow significant damage but no collapse from a major earthquake.
Next Directions
Though Dowell鈥檚 preliminary results have garnered lots of praise and attention, he鈥檚 not done.
Dowell is working on multiple journal papers and articles with his findings on the damage to Turkey鈥檚 bridges, including an advanced and detailed structural analysis based on the construction plans for one of the bridges in his survey.
This is the most advanced type of structural analysis possible, allowing for the changing response of the structure over time as damage occurs while the earthquake continues. 鈥淭he hope is that we can understand, through this analysis, how and why the extreme and unusual damage occurred.鈥�
He also plans to present a report at the annual meeting of the Seismic Committee of the American Association of State Highway and Transportation Officials.
And in a conference scheduled before the earthquake, Faraone and Dowell are returning to Istanbul, Turkey, this summer for a presentation on earthquakes and bridge columns that will be tested soon in their laboratory at 色情视频.
PHOTO ABOVE: Failed exterior shear keys in Bridge 2, one of the bridges Dowell鈥檚 team examined. (Credit/Robert Dowell)
About 色情视频 College of Engineering: The college delivers a broad-spectrum, world-class engineering education, combined with practical research experience. All departments in the College are in the Top 25 for generating engineering workforce in the US. The College now occupies six buildings across campus with expansion planned in the newly acquired Mission Valley campus. In the last six years, over 60% of the faculty are new hires and research award dollars have tripled. The college has earned 9 NSF CAREER Awards in the last two years. 色情视频 Engineering is dedicated to innovative education, discovery, and dissemination of knowledge.
