Abstract
In Urayasu City, where about 85% of the city area liquefied during the 2011 Great East Japan Earthquake, water pipes were seriously damaged due to liquefaction. Joints of water pipes were pulled out at many sites. Shaking continued at a long predominant period for a long time after the occurrence of liquefaction during the earthquake. So, the long-period shaking of liquefied ground, which was a kind of sloshing must cause large cyclic compressional and tensile strain to the water pipes in horizontal direction near some boundaries, resulting in the disconnection of the pipe joints. Then seismic response analyses were carried out to demonstrate the concentration of horizontal tensile strain at 5 areas in Urayasu City under four levels of shear modulus by considering the effect of liquefaction. Analyzed results showed large tensile strain induced near the site where the water pipes were pulled out.
