Case Study - MNRR Jump Span Temporary Support of Excavation for Proposed Foundation Installation-Video

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Video Summary

The presentation describes the temporary support of excavation (SOE) designed for the Metro-North Railroad bridge replacement over Atlantic Street in Stamford, Connecticut. The existing low-clearance bridge carried five tracks and heavy commuter traffic, which had to continue throughout construction. “Jump spans” temporarily bridged the excavation so trains could keep running while new foundations were installed.<br /><br />Design challenges included restricted headroom, closely spaced tracks, train surcharge and braking forces, and nine-day track outages. The team replaced the original drilled soldier-pile concept with micropile soldier piles anchored into bedrock, welded bracing for construction flexibility, and custom “top hats” to transfer jump-span loads to the piles.<br /><br />Careful construction and excavation staging was essential: crews installed each jump span during an outage, then advanced across the tracks while limiting excavation near active work areas. The project highlighted the need to coordinate design, railway requirements, safety, and construction sequencing.

Keywords

temporary support of excavation

Metro-North Railroad bridge replacement

jump spans

micropile soldier piles

construction staging