Lehigh Wins $5M for Natural Hazards Engineering Research

NHERI Lehigh
The Real-Time Multidirectional testing facilities in Lehigh's ATLSS Research Center enable researchers to conduct experiments that mimic the demands on structures from earthquakes and other natural disasters.

Lehigh has received a highly competitive 5-year grant of $5 million to participate in a national initiative aimed at improving the resiliency and sustainability of the civil infrastructure to better withstand the effects of earthquakes and other natural hazards. The award is being made through National Science Foundation's (NSF) $40 million Natural Hazards Engineering Research Infrastructure (NHERI) program, which was launched in September.

The grant to Lehigh will be used to operate a shared-use NHERI Experimental Facility, and will be led by James Ricles, the Bruce G. Johnston Professor of Structural Engineering and principal investigator (PI), and Richard Sause, the Joseph T. Stuart Professor of Structural Engineering and co-PI.

The NHERI program will support the operation and maintenance of seven separate shared-use facilities, including Lehigh's Experimental Facility housed at the ATLSS (Advanced Technology for Large Structural Systems) Research Center, where research will be conducted to evaluate the performance of engineering designs and materials during earthquakes, hurricanes and other storms, tsunamis, landslides and other disasters. The grant also opens up ATLSS and the other NHERI Experimental Facilities to other NSF research, regardless of discipline.

Lehigh was selected because its ATLSS facilities will enable researchers to conduct real-time, large-scale and multidirectional structural experiments that mimic the demands on structures from natural disasters, said Ricles.

In the ATLSS Center, researchers have also gained extensive experience in performing other types of large-scale experiments that will help NHERI researchers evaluate and confirm the resiliency of structural designs to natural hazards:

  • Hybrid simulation (HS), which combines large-scale physical test models with computer-based numerical simulation models;

  • Geographically distributed hybrid simulation (DHS), in which the various components of a hybrid simulation are located at different sites while data is transmitted via the Internet and interpreted in real time;

  • Real-time hybrid earthquake simulation (RTHS), in which hybrid simulations are conducted at the actual time scale of physical events;

  • Geographically distributed RTHS tests;

  • Dynamic testing, in which researchers subject large-scale physical models at real-time rates through predefined load histories;

  • Quasi-static testing, which loads large-scale physical models at slow rates through predefined load histories.

The NHERI program follows NSF's George E. Brown Jr. Network for Earthquake Engineering Simulation (NEES) program, which supported earthquake engineering, innovation and education at 15 U.S. universities, including Lehigh, from 2004-2014.

NEES researchers advanced the state of the art in earthquake retrofitting, tsunami preparation, performance-based design and other areas, said NSF officials. The NHERI program will extend these advances to the protection of life and property during severe windstorms.

"NEES research enabled us to better understand and improve soil behavior and the seismic response of structures under earthquake loading through new high-performance construction materials, seismic-resistant structural systems, and ways to strengthen soils to prevent liquefaction," said NSF program director Joy Pauschke.

"Under NHERI, future discoveries will not only mitigate the impacts of earthquakes, but also will advance our ability to protect life and property from windstorms such as hurricanes and tornadoes."

RTHS EQ Building Piping System
This image shows a real-time hybrid simulation of the effects of a severe earthquake on a multi-story building and its piping system. The simulation was performed at Lehigh's NEES RTMD Seismic Simulation Facility. Experiments similar to this, but with added complexity to capture soil-foundation effects and demands from other natural hazards, will be performed at the Lehigh NHERI Experimental Facility.

Ricles and the team at the NHERI Lehigh Experimental Facility will be hosting a researcher's workshop on November 9 to demonstrate ATLSS's capabilities for those interested in utilizing the facility to conduct research related to resiliency to natural hazards. (Information and registration for the workshop can be found here.)

"Our goal with this workshop is to provide researchers the information they need to submit a successful proposal to the National Science Foundation," Ricles said. To do that, the workshop will consist of a series of demonstrations and hands-on experimentation including topics related to soil-structure interaction, advanced sensors with digital imaging, and performance of dampers placed in a multi-story building during an earthquake.

Workshop attendees will also be broken into groups and given engineering problems to solve that involve hands-on activity in various ATLSS labs. "For researchers, it should really help develop their proposals," Ricles said. "They obviously have a lot of knowledge, but actually seeing what the NHERI Lehigh Experimental Facility is capable of might open up new possibilities and ideas regarding the specific problems they're trying to solve. The workshop is a very unique opportunity in that respect."

The NSF's Engineering for Natural Hazards division (ENH) calls for proposals every February and September, so the timing of the workshop is ideal, Ricles said. But it's in January that NHERI funding officially begins at Lehigh, and Ricles and his colleagues are ready to hit the ground running.

Shamim Pakzad, associate professor of structural engineering, and Muhannad Suleiman, associate professor of geotechnical engineering, both have ongoing NSF projects that will make use of the infrastructure at ATLSS through NHERI. Additionally, a project led by Ricles and co-PI Spencer Quiel, assistant professor of structural engineering, will examine ways to engineer a building's cladding to not only protect its interior from exposure to the elements including water and sunlight, but also to improve the building's performance against multiple hazards, including earthquakes, high winds, and blast loads.

Ricles and Quiel received the $300K from NSF for this project before the NHERI funding became official. Now, they can use ATLSS's unique, large-scale experimental capabilities to conduct the earthquake and wind tests.

Lehigh's ATLSS Center, which was founded in 1986 with support from NSF, contains some of the largest structural testing facilities in the world. The NEES real-time multidirectional (RTMD) facility allows for hybrid seismic testing and, when combined with real-time numerical simulations, enables researchers to investigate the behavior of large-scale structural components during seismic events.

ATLSS researchers have designed some of the major innovations in earthquake engineering. These include braced frames with passive and semi-active dampers, in addition to self-centering steel, concrete, and timber structures that absorb seismic loads and minimizes earthquake damage to structures.

These advances have contributed to the goal of earthquake engineers in the last half-century, which is not only to eliminate loss of life during earthquakes but also to greatly minimize the property damage and structural "down time" caused by seismic events.

Through the NEES program, Lehigh researchers have also led the way in designing and conducting large-scale real-time hybrid simulation and geographically distributed hybrid simulation experiments.

In one hybrid simulation, researchers subjected a nine-story building to conditions equivalent to those of the Los Angeles-Northridge Earthquake of 1994. They concluded that the building, which was rendered unusable by the earthquake, would not have had to be condemned if it had been fitted with semi-actively controlled magnetorheological dampers.

In an experiment conducted simultaneously at Lehigh, the University of Illinois and Rensselaer Polytechnic Institute, researchers simulated the effects of the Northridge Earthquake on a freeway bridge structural system, including several of its columns and soil-foundation. The goal of that test, which was overseen by Ricles and Richard Sause, ATLSS director and co-principal investigator on the NHERI grant, was to obtain a "holistic" picture of the effect of an earthquake on an entire infrastructure system.

"One goal of the NHERI program is to apply the knowledge gained from conducting research on structural resiliency to earthquakes to the ability of the civil infrastructure to withstand the demand from severe windstorms and other natural hazards," said Ricles.

In addition to the field of structural engineering, researchers in other fields of engineering and science will benefit from the NHERI program, including geotechnical engineering, hydraulic engineering, lifecycle engineering, mechanical engineering, materials science and computer science.

"In order to successfully perform real-time hybrid simulations of complex systems," said Ricles, "high-fidelity algorithms are required to control laboratory equipment in real time while simultaneously performing high-speed computations associated with the numerical models.

"While Lehigh has developed and implemented state-of-the-art algorithms over the past decade to conduct hybrid simulations, we will need to continue to develop advanced algorithms using a multidisciplinary approach and high-performance computing. These algorithms will enable researchers to face the many challenges in developing solutions to improve the resiliency and sustainability of the civil infrastructure against different natural hazards."

And for more information, take this virtual tour of the Lehigh NHERI Experimental Facility:

Story by Kurt Pfitzer
Additional Reporting by John Gilpatrick



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