Computer Analysis of Buried Stormwater Chamber Structures

In the last two decades, stormwater chamber products have become popular in the United States and other countries for managing stormwater. These products are typically arch-shaped and light-weight for efficient transportation, handling, and field installation. Despite the popularization of the products, currently there is a lack of rational analysis/design methods for these structures. Also, with little effort to establish industry standards, these chambers come with various raw materials, wall designs, and cross-sectional shapes. In this paper, a software package was used to perform a series of two-dimensional numerical simulations of both single and multiple chamber systems installed in the ground. Based on the simulation results, several key issues related to stormwater chamber structure were discussed, such as the optimum cross-sectional geometry, failure modes, and chamber spacing. Computer simulation results were also viewed in light of observations made during recent field loading tests. Main conclusions reached in the study are that (1) the arch-shaped chamber structures, having either semicircular or elliptical cross-sectional shape, are capable of sustaining a high level of external loading by distributing the stresses to the surrounding soil columns; and (2) the foot region of the chamber appears to be critical and needs special attention.