Evaluation of Fire Effects on Precast, Prestressed Concrete Members

Exposure of concrete members to high temperatures can affect the structural performance of concrete and embedded reinforcement in numerous ways including changes in material properties, loss of strength, and relaxation of prestressing forces in pre-stressed concrete members. The assessment of concrete members exposed to high temperatures follows both testing and analytical methods. A typical evaluation may include non-destructive testing, destructive testing, evaluation of fire intensity, determination of temperature profiles, and assessment of residual strength and prestressing losses. This paper includes the authors' experience with the assessment of prestressed double-tee beams in parking garages that have been exposed to fire and high temperatures. The authors discuss both general information associated with the evaluation process (and review of relevant, published literature) as well as considerations specific to the presented case studies. These include consideration of effects of high temperatures on localized components of the double-tees, as well as potential remedial repairs.