Transient Thermal Behavior of Composite Bridges

Analytical and experimental investigations into the transient thermal behavior of continuous composite steel beam‐reinforced concrete slab highway bridges are reported. Temperatures and deformations were measured during transient cooling of a 0.354 scale model of a three‐span continuous bridge. The model bridge was 53 ft 1‐1/4 in. (16.2 m) long. Slab dimensions were 10 ft 6‐3/4 in. (3.2 m) wide by 2‐7/16 in. (62 mm) thick. It was supported on four $\mathrm{W10}\times 15(\mathrm{W254}\times 6.8)$ continuous steel beams. A numerical procedure is presented for the solution of transient temperatures in composite slab‐steel beam highway bridges. The two‐dimensional finite element analysis predict the temperature distributions of the cross section to $\pm 0.5°F(\pm 0.3°C)\text{.}$ A linear temperature rectangular finite element is used. Statistical analyses indicate a better than 0.99 probability of correlation between the predicted and measured temperatures. The temperature history of the model bridge requires 462 time steps of 10 seconds each to cover the total cooling period. A finite element thermoelastic analysis is used to compute strains, stresses and deflections. The method is applicable to other systems of composite construction.