Nannis & Associates, Inc. has extensive experience in renovation and rehabilitation work. In the past 20 years, we have been involved in more than 67 major renovations and rehabilitations throughout the Southeast U.S. and in many historic districts such as Charleston, SC, Greenville, SC, Columbus, GA, Savannah, GA and Atlanta, GA. As a precondition to renovation or rehabilitation of any structure, one must establish the structural integrity of the frame, its components and its foundation. A building, over time, is subjected to deterioration induced by pollution, wind, temperature variations, rains, and other natural forces, but it also can be greatly affected by changes in the constructed environment surrounding it and by additions to its own structure. In evaluating the integrity of the structure, Nannis & Associates may be required to perform the following:
- Study the history of the structure.
- Perform a condition survey to identify defects such as excessive deflections, cracking, fracture, spalls, or corrosion of metals.
- Establish or verify with field measurements “as-built” conditions which may vary from that shown on any existing drawings (if available).
- Establish strength of building materials by reviewing construction documents supplemented by laboratory tests.
- Calculate the present structural capacity of the structural frame, its components and its foundation.
- In the event questions or doubts still persist regarding the strength and load-carrying capacity, perform a full-scale load test of elements or an entire structural section.
- Study and design the repair of all existing defects and/or the upgrading to the current building code / occupancy.
It is quite common when working with a major renovation and/or new construction in a historic area to perform pre & post construction surveys. This entails conducting structural surveys and documenting existing conditions of adjacent buildings both prior to and after the completion of the construction project to protect the owner from claims and losses. For example, prior to the construction of the Charleston Federal Courthouse Annex (corner of Broad and Meeting), Nannis and Associates performed pre construction surveys on all existing buildings and residential homes within 500 feet radius around the proposed new addition. This was done to evaluate the possible damage of these structures that would be caused by the vibrations of the pile driving operation. To reduce the possibility of damage to other historic buildings such as St. Michaels Church, Nannis and Associates recommended the use of auger cast piles (caissons) to be installed by the slurry method (a technique never used in the Charleston area). This method negated the vibration of pile driving thus minimized possible damage to adjacent structures. Also, the Courthouse Annex was analyzed and designed for High Seismic activity.