Assessment Of Existing Foundations For Building Upgrade Projects

Building owners are often faced with the question of whether to demolish and rebuild to gain extra floor space, or to assess if existing buildings can support additional levels. Aside from the adequacy of the superstructure, consideration must be given to the capacity of the existing foundation system to cater for the increased loading. Douglas Partners (DP) has employed a range of portable equipment for use in often congested basements and poor access areas, to investigate and develop a geotechnical model for such sites.

Where no records exist, or where the assessment of the existing pile foundation is required for QA purposes, low-strain pile testing techniques may be used to determine pile lengths. The geotechnical model and existing foundation details are subsequently combined to assess the capacity and expected settlement performance of the existing foundation system. In most cases, increased confidence in parameters and advances in foundation analysis and design methods has permitted extra floors to be added, thus realising a large capital benefit for the owner of the building.