<P>The Crum Creek Viaduct Replacement Project is a unique design-build (D-B) project that replaced a bridge on an existing alignment using accelerated bridge construction (ABC) techniques.The D-B approach to replace the 121-year-old rail viaduct on the Media-Elwyn Regional Rail Line over Crum Creek was executed for the Southeastern Pennsylvania Transit Authority (SEPTA). The team of Walsh Construction and FIGG Bridge Engineers Inc. provided innovative solutions to designing and delivering the new bridge on time with a fast-paced schedule. The aggressive schedule required daily coordination between the owner, contractor and designer to ensure permitting, design and site access remained on schedule. The unique challenges the D-B team faced to meet the SEPTA included: an aggressive schedule, complex ABC designs and innovative construction techniques which coupled to successfully accomplish the project.</P>
<P>The existing Crum Creek Viaduct, which spans one of four deep valleys along the Media/Elwyn Regional Rail line between Philadelphia and Elwyn, was built in the 1890s. By the early 2000s after decades of monitoring and repairs, conditions dictated that speed restrictions be imposed, freight be restricted from the inbound track and weight restrictions be placed on all freight on the line. By 2013, facing a lack of adequate capital funding and the need to replace the viaduct, SEPTA started evaluating alternative service plans on the line.In November 2013, however, transportation funding was provided after Pennsylvania Act 89 was signed into law. SEPTA moved quickly on the replacement of the Crum Creek Viaduct. To achieve a fast replacement of the structure, the D-B contracting method was selected.</P>
<P>After completing a thorough project review and preliminary design study, SEPTA released a request for proposal (RFP) with a preliminary design concept featuring the following critical requirements:oThe new bridge must be designed and constructed to exactly match the new alignment;oThe new bridge must be designed and constructed to have minimal effects on the existing viaduct while in service.</P>
