Date: Tue, 28 Feb 1995 12:53:02 -0500 From: castill@nsf.gov (Clifford J. Astill) Subject: NSF Press Release 95-12 Content-Length: 6861 X-Lines: 135 Status: RO Organization: National Science Foundation Beth Gaston February 23, 1995 (703) 306-1070 NSF PR 95-12 MODERN BUILDINGS FARED WELL IN KOBE QUAKE, ACCORDING TO PRELIMINARY REPORT Most modern buildings -- and structures retrofitted with up-to-date engineering techniques -- fared well in the Kobe quake, the 6.8 January 17 temblor. Much of the damage occurred in traditionally built older homes and in areas near the coast where liquefaction of the soil caused instability in structures. At the time of the earthquake, a team scientists were in Osaka, 30 km east of Kobe, for a National Science Foundation-funded U.S. Japan Workshop on Urban Earthquake Hazard Reduction, co-sponsored by the Earthquake Engineering Research Institute and the Japan Institute of Social Safety Science. The workshop participants immediately undertook preliminary post-earthquake reconnaissance efforts funded by the National Science Foundation (NSF). The team recently issued a preliminary report describing their findings. "After a damaging earthquake, it is important to get researchers into the field to collect information and make observations as soon as possible because much of the data is perishable and will disappear when the recovery process commences," said William Anderson, head of the earthquake hazard mitigation program at NSF. "Because the U.S. group, comprised of researchers from such disciplines as earthquake engineering, seismology and the social sciences, was already in Osaka at the time of the earthquake, they were able to undertake the earliest possible investigation of that event and collect information that would later be unavailable to other investigators." The earthquake has killed more than 5,000 people and caused more than $200 billion in damage. More than 56,200 buildings were destroyed in the quake and subsequent fires. Preliminary assessment indicated the single most significant cause of damage is the proximity of affected cities to the fault rupture. In areas of heavy damage, the pattern indicates that a strong horizontal pulse, rather than the repeated shaking, caused the majority of the destruction. The most extensively and severely damaged structures were smaller commercial buildings (often with residences upstairs) constructed with limited engineering design and traditional homes. The smaller commercial and mixed occupancy buildings are typically framed with wood or light steel and have walls of stucco over wood slats. Many of these buildings have a large shop window in the front and lack interior walls, factors which weaken the first floor. Traditional homes, typically those built before the 1970s, have heavy tile roofs with tiles set in a thick clay and mud mortar, few partitions, and are not waterproofed which causes widespread dry rot and water damage. Little nailing is used; wood joinery is more common. Many casualties were found in damaged and collapsed traditional homes. The heavy tile roofs stressed the walls, which cracked, crumbled and often collapsed, triggering fires from broken gas pipes. The Kobe earthquake exposed more modern and engineered buildings to stronger forces than any previous earthquake. The preliminary report indicates more studies are needed to evaluate seismic codes, design practice and construction methods; and to make improvements based on the studies. The failure of transportation structures produced dramatic and frightening images flashed across the world following the quake. Perhaps the most memorable image was a bridge on the Hanshin expressway which "rolled over." Most of the damage to bridges occurred to older structures designed before modern earthquake engineering. The damage was typically column shear and structures that broke instead of bending. Other more modern structures suffered extensive damage due to liquefiable soils along the bay. The Akashi Suspension Bridge bore the brunt of the earthquake with essentially no damage -- an example of how engineering can prevent damage during earthquakes. Rail facilities were hard hit -- and more casualties and fatalities would have resulted if the quake had occurred during commute times. Railway structures failed because of shear failures in support structures, inadequate restraint between spans at critical joints, and large ground movements causing spans to fall off supports; also many cars rolled because of the ground movement. The Port of Kobe suffered extensive damage, mainly due to liquefaction. Modern design criteria are more stringent and liquefiable soils can now be identified and the effects mitigated. Had the port conformed to modern design standards, the damage would likely have still been severe -- but less than the damage that occurred. Electric power and telecommunications systems performed remarkably well during the earthquake, with little or no disruption to service. Water pipelines sustained severe damage, causing a general lack of service in Kobe, Ashiya and Nishinomiya. Some residents were informed to expect no water service for two months. The lack of water also inhibited firefighting efforts. It is expected that the sewer system suffered similar damage. The gas system sustained numerous breaks, which will interrupt service to residents for several months. The formal emergency response confirms the oft-repeated warning that citizens should be prepared to be on their own for 72 hours following a disaster. It takes time for response agencies to identify and locate problems and organize resources. The failure of transportation structures inhibited emergency response. Also of note: access to damaged buildings was not prohibited -- and people returned to cracked, crumbling and dangerous homes to seek shelter and to gather belongings, putting themselves again at risk. "Though unfortunate, large earthquakes are natural experiments that provide the opportunity to significantly advance knowledge in earthquake engineering and related fields. Thus for many years NSF has also supported quick-response post earthquake investigations to complement the analytical and laboratory research it funds," Anderson said. "EERI has long played a major role in such efforts through its NSF-funded Learning from Earthquakes Project." Copies of the preliminary report may be purchased for $15 prepaid from the Earthquake Engineering Research Institute, 499 Fourteenth Street., Suite 320, Oakland CA, 94612-1934; tel (510) 451-0905. California residents should add California sales tax of 8.25%; international orders should add $2.50 for shipping and handling. -end- For more information on NSF PR 95-12, contact Beth Gaston (egaston) via e-mail or at (703) 306-1070.