Experimental Investigation on Stress Distribution in Florida Bulb-Tee Concrete Girders

The appearance of longitudinal cracking and spalling in the web section near the end block of Florida bulb-tee concrete girders have raised some concerns regarding possible problems which may be inherent in the design and construction procedures of the girders. Several factors believed to cause the stress buildup and the cracking were investigated in this study. Results showed that stress accumulation started at the end of the transition section where the web width gradually reduced to 178 mm (7 in.). A wedging effect due to out-of-plane stresses was the most critical factor causing stress buildups in the transition zone. The effect of grout pressure was more severe in ducts with oval cross sections than in round ones.