Date of Award
Doctor of Philosophy
Civil, Construction, and Environmental Engineering
Brent M. Phares
Bridges constructed with adjacent precast prestressed concrete box beams have been in service for many years and provide an economical solution for short and medium span bridges. A recurring problem with this type of bridge is the cracking in the longitudinal joints between adjacent beams, resulting in reflective cracks forming in the asphalt wearing surface or concrete deck. AASHTO (2014) states that the differential shrinkage due to differences in age, concrete mix, environmental conditions etc., have been observed to cause internal force effects that are difficult to predict at the design phase. The objective of this research is to develop an innovative design of the connection used in adjacent precast concrete box beam bridges to eliminate cracking and leakage in the longitudinal joints between adjacent boxes.
To meet the research goal, a comprehensive review of relevant specifications and technical literature from the past twenty years has been conducted to study the design and construction attributes influencing the long-term performance of the box beam bridge joint and identify the reasons that cause cracking in the joint between the adjacent box beams. A three step evaluation of joint was conducted on the material level, small scale level and full scale level. In each level of evaluation, both experimental and analytical evaluation were conducted. The results indicated that the innovative connection can create a crack-free joint without the utilization of a shear key nor transverse post-tensioning. Both experimental and analytical results indicate that the innovative joint showed good performance in resisting joint cracks in both the early-age and the long-term service life of the bridge. The “compression-dominate-joint” created by the expansive joint material combined with transverse reinforcing steel across the interface is expected to overcome the difficulties in predicting the early-age internal forces during the design phase stated by AASHTO (2014). To further investigate the performance of this joint detail, it is recommended that a field trial be completed. During this field trial, the bridge should be monitored and evaluated during early age concrete curing as well as for a period of at least two years following construction.
Liu, Zhengyu, "Evaluation of an innovative joint design for the adjacent box beam bridges" (2018). Graduate Theses and Dissertations. 16621.