Two-dimensional analysis of the effect of fault rupture on buildings with shallow foundations

The behaviour of a building founded on a soil layer overlying a strike-slip fault in basement rock is studied to determine conditions under which rupture will be diverted around the structure. The problem is simplified by assuming the structure is long in the direction of the fault strike and by approximating increases in normal stress in the soil due to building weight by increases in mean stress. Closed-form expressions are obtained for work done on the soil-structure system by a unit offset on the fault, under alternative modes of failure. The main result is that rupture will be diverted around the structure provided bearing stresses are sufficiently great. Otherwise, with light structures, vertical rupture will occur in the soil, with the structure either slipping on its foundation or the foundation itself rupturing, depending upon its strength. These results are verified qualitatively by model tests.