Experimental modeling of strip footing adjacent to non-yielding retaining wall

Abstract

A series of reduced-scale models were tested to assess the performance of non-yielding basement wall due to strip footing constructed adjacent to it. Construction design parameters such as strip footing width (B), its distance from non-yielding wall back (a), and footing embedment depth below the backfill surface (df) have been considered in this study. This paper presents results of five model tests that isolate effects of non-yielding wall on the strip ultimate footing bearing capacity. The opposite effect of the strip footing distance design parameters on the non-yielding wall responses is also investigated. Experimental results revealed that the strip footing load-carrying capacity increased, and the settlement decreased as its distance from the back of non-yielding wall increased. Furthermore, the vertically loaded strip footing imposed significant vertical and horizontal forces at the back of the non-yielding wall. Results also indicate that distance a > 4B between the footing and the back of the wall enabled the strip footing to mobilize ultimate load-carrying capacity comparable to both control strip footing test and value calculated with Terzaghi’s equation. Comparison of the measured and predicted lateral forces showed that using elastic theory method together with Jacky formula for at-rest lateral earth pressure coefficient led to about 23–35% underestimation of the measured lateral forces. However, including sand overconsolidation ratio, OCR = 2 resulted in an overestimation of the lateral forces by about 20–29% of the measured value. Finally, results of the experimental program are used to identify sources of conservativeness and non-conservativeness in the current design methodologies used to calculate lateral forces imposed on non-yielding walls due to adjacent strip footing and suggested necessary modifications.