Temporary Bracing

by Don Friedman on February 14, 2012

We are currently working on combining two brownstones to create one very large single family residential home on the Upper West Side. The buildings have landmarked facades which we will preserve while creating a new steel framed building within the existing facade. The existing party wall dividing the two lots will be removed to create one 36ft x 60ft floor plate.

The project will involve extensive excavation to deepen the existing cellar level, as a result underpinning will be required at the adjacent properties and at the existing front facade. To brace the adjacent properties and the facade to remain Old Structures has designed a steel bracing system which spans across the entire site, party wall to party wall. This bracing specifically avoided the typical raker and wailer detail. By bracing clear across the site we allow full access to foundation equipment and crews on this cramped site.

After completing the required masonry repairs to the party walls at each side of the project the bracing was installed. At the front tie arms reach out from the bracing and grab the brick masonry facade at the first four levels. At the upper floor ties to the existing wood mansard roof framing are provided.

With the bracing complete the floors and center party wall were then removed from the top down. As the new permanent structural steel frame for the proposed building is erected the temporary bracing will be removed floor by floor, following the new construction. The final structure will tie to the front facade and side walls, providing permanent stability. The project is currently beginning excavation and underpinning work.

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