Analytical and numerical assessment of Egyptian code compared with international standards for the analysis of braced diaphragm wall

In urban areas where space and property are a major constraint when constructing a deep excavation, the use of a stable and effective retaining system is essential. The choice of the retaining system will depend on the site condition, the expected earth pressure and the existence of water. Diaphragm walls are commonly used as a retaining system that can withstand high values of earth pressure and also have good performance with water existence. The design output of retaining system depends mainly on soil parameters, site conditions and adapted design approach. There are well known two design approaches for geotechnical problems: working stress design approach WSD which adapts a global safety factor for all uncertaintiesassociated with geotechnical design, and limit state design approach LSD which accounts for uncertainties by applying partial safety factors for different variables that affects the design output. Different standards adapt different design approachesi.e., the Egyptian code of practice ECP 202 adapts WSD approach; EN 1997 along with BS8002 and AASHTO adapts LSD approach. This study aims to emphasize the influence of adapting different design approaches on design output results for a strutted diaphragm wall. Comparing the design output results between ECP 202, AASHTO, EN 1997 DA1-1, EN 1997 DA1-2, and BS 8002 it was found that AASHTO design output gave the most conservative results for embedment depth and straining actions on the retaining system, as it uses load and resistance factored design method LRFD. The ECP 202 gave a high estimate for embedment depth when compared to EN 1997 DA1-1, EN 1997 DA1-2, and BS 8002.