Structural Engineers and Building Envelope Consultants


Herb Alpert Educational Village

James Turrell at the Guggenheim

Microsoft Store Times Square


Umbilic Torus

New World Symphony

University of Rochester

West 23rd Street Triplex



© Copyright Gilsanz Murray Steficek 2013
News 41

April 3, 2013
David Hoy presenting at the 2013 Architectural Engineering
Institute (AEI) Conference

April 3 - 5, 2013  |  Penn State, University Park, PA
Sponsored by Dept of Architectural Engineering of Pennsylvania State University and the Architectural Engineering Institute of ASCE     

“Leveling Wood Floors by Jacking”
GMS monitored and analyzed the jacking up of existing deflected wood floor framing within a four story brownstone structure.  The wood floor framing had longstanding deflections of 2” maximum at each floor, which the Owner desired to remove as part of a gut rehab. GMS could not definitively quantify the effect of removing these deflections on the state of stress in the existing floor framing via calculations alone, because of the known but unpredictable tendency of wood to relax elastically over time. To monitor the floors and move them back to level, a Contractor installed temporary posts and framing under each floor level, and two hydraulic jacks (each with a pressure gauge) provided were underneath the lowest floor. The jacks were then extended in small increments, several times a week, raising all four floors gradually.   Gauge readings were taken before and after each increment of jacking.  The readings allowed stress levels in the framing and temporary shoring to be monitored over time. The results of the monitoring and analysis confirmed that the jacked floor members did partly relax over time, and that the floor could safely be jacked back to level. Gauge readings also allowed design of supplemental permanent strengthening to keep the floors in their level final position.

David Hoy

David Hoy, PE