Influence of Buildings on Potential Liquefaction Damage

The potential for liquefaction below a building is often evaluated by treating the soil as if it were in the free field. A summary of available field case histories, shaking table model tests, and centrifuge model tests is presented; this clearly indicates that the excess pore pressure distribution near a building can be much different than in the free field. Modifications to the typical free‐field liquefaction analysis procedure to account for changes in the vertical stress, horizontal shear stresses, and overconsolidation ratio due to a structure are suggested. Soil‐structure interaction effects on the potential for liquefaction are also examined. Comparisions with free‐field conditions suggest that the potential for liquefaction damage may be greater or lesser beneath a building depending on the building type and soil density. Sands below short‐period, low‐rise structures appear to have higher potential for liquefaction than predicted by simplified methods while sands below tall, long‐period structures appear to have lower liquefaction potential than sands in the free field.