Cutting 100 feet into Manhattan Bedrock

GEODesign provided geotechnical, geostructural, geoenvironmental and related construction-period engineering support to John P. Picone (JPP) for construction of the Site P Station Entrance for the No. 7 Flushing Line Extension (Borough of Manhattan), for the MTA/NYCTA.

The Site P Station is located across from the Jacob Javits Center between 34th and 35th Streets and 10th and 11th Avenues.  The Station design and construction included deep soil and rock excavation to depths over 100 feet below ground surface, to connect the new Station entrance with the existing Amtrak tunnel and 34th Street Station Cavern. GEODesign designed support of excavation (SOE) systems in both soil and bedrock.

The SOE design to retain earth included tied-back soldier piles and lagging systems directly adjacent to existing structures, and interim structures to facilitate construction sequencing and concurrent construction activities. Unique aspects of the SOE soil work included requirements for phased excavation and concurrent detensioning of existing tie-back systems supporting site access to the Amtrak tunnel.

Rock support design required field mapping of rock structure and joint sets and related rock mechanics analyses to evaluate areas for design and installation of rock bolting and support systems for the conditions exposed by rock removal.  The designs included excavation sequencing requirements for the removal of rock and installation of reinforcement at the exposed rock faces adjacent to existing structures.

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