Experimental investigation into the seismic behavior of nuclear power plant shear wall structures

Nuclear power plant structures are designed to resist large earthquakes. However, as new data are obtained on earthquake activity throughout the United States, plant design earthquake levels have increased. The U.S. Nuclear Regulatory Commission is sponsoring an analytical-experimental research program to obtain information on the strucutral response of nuclear power plant shear wall strucutres subjected to earthquake motions within and beyond their design basis. Using different size scale models constructed with microconcrete and prototypical concrete this research has demonstrated consistent results for measured values of stiffness at load levels within the design basis. Furthermore, the values are well below the theoretical stiffnesses calculated from an uncracked cross-section strength-of-materials approach. Current program emphasis is to assess the credibility of previous experimental work by beginning to resolve the 'stiffness difference' issue. (orig.)