Comparative evaluation of building responses to an adjacent braced excavation

Abstract

Construction data from a large braced excavation are evaluated in comparison to several methods of predicting the response of buildings to excavation-induced ground movements. The project included an excavation of up to about 20 m depth, over 650 m long, and 20 m wide made through generally competent glacial overburden. Excavation support was achieved using a braced soldier-pile and lagging wall system. A detailed instrumentation program was undertaken by the owner to monitor contractor compliance with ground and structure movement criteria. Data from 46 structures, with damage ranging from negligible to moderate categories, are presented, with four cases presented in detail. A modified approach to estimating potential damage categorization is provided and compared to case histories. Good agreement is demonstrated between actual and estimated damage categories.Key words: building damage, excavations, cracking, angular distortion, settlement.