Damage to Two Apartment Buildings Due to Moisture Variation of Expansive Soil

Abstract

The purpose of this paper is to describe the cause of distress to buildings H and J at the Calavo Woods Condominiums. The damage resulted in a lawsuit, during which the writer presented expert testimony for one of the cross-defendants. It was observed that the greatest amount of damage occurs at the area of the maximum angular distortion of the foundation. The damage at this area, classified as severe, included interior wall-board cracks, distortion of window and door frames, floors sloping noticeably, and walls leaning or bulging noticeably. The results of subsurface exploration revealed shallow expansive fill overlying natural red-brown expansive clay. The soil is classified as a highly expansive clay of high plasticity. The foundation displacement and severe damage was caused by differences in moisture content of the red-brown clay. On one side of the foundation, added moisture caused the clay to expand and the foundation to heave, while on the other side of the foundation, where the clay was drier, perhaps even shrinkage of the clay caused settlement of the foundation. The main lesson learned from this case history is the mistake in putting planter areas directly adjacent to the perimeter of the foundation.