The performance of a circular cofferdam braced with reinforced concrete ring beams is presented in this paper. The cofferdams were built using a continuous circular wall, made of interlocked sheet pile modular pieces, internally braced with ring beams. During concrete placement of the exposed ring beams, curing conditions were affected by temperatures below the freezing point of water which resulted in lower concrete strength and stiffness values than those estimated during the design phase. A numerical model is presented to study the influence on the performance of creep, shrinkage, temperature, and aging of concrete. Lateral wall displacements are computed with the model only as a result of coupled temperature and concrete time-dependent effects and studied individually with a parametric study. Those effects contributed about 17% of the total maximum measured lateral wall deformations. Creep effects had the largest contribution with about 8%, while aging of concrete and shrinkage contributed less than 5%.