The longevity of a large number of reinforced concrete bridge piers has been compromised as a result of Alkali-Silica Reaction (ASR) and Delayed Ettringite Formation (DEF). These structures need to be assessed for strength and performance to ensure their general load capacity and safety. It is shown that present code-based methods of analysis, whether they be the sectional method or strut-and-tie methods, are unable to discriminate between these concrete elements without and with the effects of ASR/DEF. A Compatibility Strut-and-Tie Modeling (C-STM) technique is therefore used. Prestress forces are applied at certain truss nodes to mimic the swelling effects of ASR/DEF damage to the concrete. The computational C-STM approach is verified against several large-scale experimental tests. It is observed that the C-STM predicts the overall force-deformation behavior of the structure without and with ASR/DEF effects with good accuracy. © 2013 American Society of Civil Engineers.