Accelerated Design/Build of the SEPTA Crum Creek Viaduct

摘要

The Crum Creek Viaduct Replacement Project is a unique accelerated bridge design/build project that replaced a bridge on an existing alignment. The design/build approach to replace the 121-year old rail viaduct bridge on the busy Media-Elwyn Regional Line in Delaware County over the Crum Creek waterway was accomplished for the Southeastern Pennsylvania Transit Authority (SEPTA). The new steel girder bridge has five spans and is 735’ long with a maximum span length of 157’. A Bridge Monitoring System was installed on the existing structure to monitor movements of the existing bridge as well as the stability of the steep slopes during construction. The Design/Build Team provided innovative solutions to designing and delivering the new bridge on-time with a fast-paced schedule, which only permitted a eleven-week rail shut down to allow completion of existing bridge demolition, superstructure and deck erection, rail work, catenary electric transmission, and signal system installation. During the eleven-week shutdown, work was performed on a 24-hour a day, 7-day a week schedule. The aggressive project schedule required daily coordination between the owner, contractor and designer to ensure permitting, design and site access remained on schedule. The new bridge girders were assembled on one side of the existing bridge, including the precast deck and were supported by new straddle bents built under the existing bridge while the existing bridge remained in full operation. The lateral slide Accelerated Bridge Construction technique was used to move the new bridge into place. Dramatic video shows how it was all accomplished.