If your project has you in a tight spot, GeoSonics/Vibra-Tech has the monitoring technology to provide you room to breathe.
INTECH Construction Inc., based in Philadelphia, was awarded the multimillion-dollar contract for the construction of the new, 100,000 square feet Curtis Institute of Music, located in the 1600 block of Locust Street in downtown Philadelphia. This site, occupied by the former Locust Club, was chosen due to the presence of the historic facades (circa 1855) in the neighborhood which were to be incorporated into the new building design.
In order to complete this project, the existing Locust Club, and two adjacent buildings to either side, had to be demolished while preserving the historic stone facades of all three buildings. The existing historic facade of the Locust Club and adjacent buildings were key design elements of the new Curtis Institute and needed to be stabilized and supported during demolition and underpinning. Since the entire block of buildings was continuous with party-walls between neighboring buildings, it was also necessary to support and protect these party-walls during demolition and underpinning. Another concern was that the final elevation for the foundation of the Curtis Institute would be 20 feet below the existing foundations for adjacent buildings. Finally, existing subway tunnels running underground and in front of the site needed to be protected during demolition and construction activities.
Prior to the start of demolition, inspection services for adjacent structures surrounding the site were provided. This service also included the inspection of approximately 100 linear feet of the Port Authority Transit Corporation (PATCO) subway tunnel running below ground and in front of the site. In addition to inspections, and at the request of the project owner, a floor level survey was conducted in a three-story building located directly behind the project site. This survey consisted of preparing a scaled floor plan for the entire three-story building and using a laser level to measure the elevation change from the center to the four corners of each room. The purpose of this survey was to document the levelness of the floors prior to and after heavy demolition.
Re:mote seismograph stations were installed in the basements of surrounding homes as well as on the adjacent wall of the PATCO tunnel closest to the demolition area to monitor vibration levels for concordance to the project vibration criteria. All Re:mote systems were programmed to record the peak vibration levels every 15 seconds and automatically send email notifications to the appropriate project personnel when vibration levels were above the project criteria.
In order to monitor the movement of the building facades and party-walls, GeoSonics/Vibra-Tech installed a series of biaxial tilt monitoring devices on both facades and party-walls at the second and fourth floor levels. These tilt monitors measure the vertical and horizontal movement of structures. All tilt monitors were wired to remote data logger locations where tilt monitoring data was recorded and stored every five minutes. Baseline readings of horizontal and vertical position were recorded to serve as a baseline for all subsequent data. Every hour, the data loggers were remotely polled for data collection. An email alarm notification was also in place to warn project personnel if movement at any time was detected which exceeded the design criteria for allowable movement.