EVALUATION OF CRACKS OF HATHAWAY PRECAST CONCRETE SEGMENTAL BOX GIRDER BRIDGE

摘要

The Hathaway Bridge, an eastbound and westbound bridge pair, is located in Panama City, Florida, USA. Each ofrnthe pair consists of a single box precast concrete segmental girder with a deck width of 24,4 m (80 ft). The lengthsrnof the eastbound and westbound bridges are 1031,43 m (3384 ft) and 1162,93 m (3815 ft) respectively. To date,rnthese are the largest single-cell precast segments without internal struts fabricated in the USA. Unfortunately,rnduring construction many web cracks developed in the external anchorage areas. The purpose of this investigationrnis to identify the main causes of the cracks and to provide some design recommendations for large precast concreternsegmental box girders. First, a brief description of the bridge is given. Then, analytical models for the bridge, posttensionrnforces, and construction forces are presented. The analytical results show that the external longitudinal posttensionrnforces can cause a significant high tensile stress in the inside face of the web around the anchorages. Therninformation presented in this paper can assist bridge engineers in the design of concrete segmental box girderrnbridges.