What are the steps needed to make concrete buildings with infill walls safer in earthquakes? Researchers and engineers from the United States, Pakistan and Nepal met in Kathmandu July 2010 to discuss options.
These buildings have a reinforced concrete frame, often lacking earthquake-resistant ductile details, and unreinforced masonry walls. Low construction cost, made possible by readily available materials and simple building practices, makes frames-with-infill one of the world’s most common building types. Regrettably, they greatly increase global earthquake risk, and caused tens of thousands of deaths during this past decade’s major earthquakes.
Participants visit a framed infill building under construction in suburban Kathmandu.
Meeting participants sought to harness the positive aspects of this very popular structural system while also improving global earthquake safety. Infill walls provide useful engineering properties – strength, stiffness and damping – that engineers can mobilize to improve seismic performance. Participants postulated that with appropriate guidance, engineers and builders could make relatively modest changes to their current practices to create what new or retrofitted buildings that intentionally make beneficial use of infill walls to achieve earthquake safety benefits. They termed this adapted building type "framed infill."
Participants identified specific products and dissemination mechanisms that would have a positive impact on infill buildings’ earthquake safety, as well as a comprehensive set of research activities needed to generate those products. Eighteen people participated, including representatives from GeoHazards International, University of California Berkeley, Stanford University, Tipping Mar + Associates, NSET-Nepal, Tribhuvan University, Kathmandu and NED University of Engineering and Technology, Karachi.
Residential/commercial mixed-use infilled frame buildings such as this one being built in Kathmandu are very common in many areas of the world.
Participants intend to pursue future collaborative research to improve the behavior of these buildings through the “framed infill network”, an international, virtual network of earthquake engineering researchers and professionals. The Pakistan-US Science and Technology Cooperation Program will provide seed funding for the network.
The meeting was funded by the National Science Foundation under Grant No. OISE-1038198, with supplemental assistance provided by the Pakistan-US Science and Technology Cooperation Program, which is funded by the US Agency for International Development. NSET-Nepal, a Kathmandu-based earthquake safety organization and long-standing GeoHazards International partner, graciously hosted the meetings.
Follow the progress of the Framed Infill Network at www.framedinfill.org.