The wall was put to test recently by engineers at the UC San Diego Englekirk Structural Engineering Center, which has the largest outdoor shake table in the United States. During the first series of tests, led by Dawn Cheng, a UCSD engineering alumna and now a civil engineering professor at UC Davis, researchers investigated the seismic response of a semi-gravity reinforced concrete cantilever wall.
California has thousands of miles of these types of retaining walls on highways, roads, bridges and oceanside bluffs that have withstood earthquakes in the past. However, the seismic design of these walls has not been extensively developed. The outcome of this research, funded by Caltrans, will ensure that future retaining wall systems are designed to a higher performance standard and existing systems are upgraded and retrofitted to offer satisfactory performance to provide a safe and mobile transportation system in California.
Retaining walls – mostly made of concrete and steel – are normally used to support traffic loads and to create more of an abrupt change in elevation than a slope typically can. The main objective is trying to come up with a better understanding by observing how these structures behave and what kind of failure we can expect during an earthquake and to obtain some of the performance data so we can come up with better analytical models and design guideline methodologies,” Cheng said. “We also want to look at the behavior of the structure when the soil is interacting with the system under earthquake shaking.”
“A lot of the sound walls are connected to the retailing walls. The design of that is critical because you are handling a bigger structure. The behavior is different,” she said. “A lot of the retaining walls are supporting the sound walls in the field on the highways and overpasses. The performance under a dynamic earthquake is different when you have a sound wall on top because of the additional mass that changes the weight and stiffness of the system. In an earthquake you have to take that into account during the design process.”
This project is unique, Cheng said, because it is the first comprehensive system level earthquake simulation test of a full-scale interactive soil-retaining wall structure supporting a sound wall.
“UC San Diego has one of largest and most unique testing facilities in the world,” she said. “The Englekirk Center has all the state-of-the-art testing facilities and there is a lot of technical support. The other reason this site was unique is because it has a large Caltrans funded laminar soil box and a soil pit on the site. UCSD is also the place where I did my Ph.D. research".
The research performed by Cheng and her colleagues will give Caltrans the opportunity to check its current retaining wall designs and input any necessary changes, according to Kathryn Griswell, ERS Specialist for Caltrans’ Office of Design & Technical Services. “This is a brand new modification and it’s time to find out how it behaves under an earthquake,” Griswell said. “These types of walls rarely fall down and cause hazards or loss of lives or other safety issues. Normally what we have to deal with are maintenance issues and costly repairs from earthquakes, so we’re looking to modify the designs whenever necessary to keep costs down.”
Andrea Siedsma | EurekAlert!
Flexible protection for "smart" building and façade components
30.11.2016 | Fraunhofer-Institut für Silicatforschung ISC
Healthy living without damp and mold
16.11.2016 | Fraunhofer-Gesellschaft
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy