Anthony J. Celebrezze Federal Building
This 32 story skyscraper has 1-million SF of space. The original curtain wall system needed replacement which entailed meeting the current ISC security design standards for windows. Also, a preliminary progressive collapse study performed for the building by others concluded that major structural retrofit of the steel column for was needed to meet GSA standards for progressive collapse. The security issues were compounded by a Department of Defense tenant who occupied over 25% of the building and planned to leave if the UFC standards were not met.
Hinman developed a replacement design for the curtain system to meet both ISC and UFC standards, taking advantage of the reduction of air-blast due to height and setback to public streets and adjacent properties. We also performed a non-linear dynamic analysis of the building to evaluate its performance to meet both the GSA and UFC standards to resist progressive collapse. This analysis concluded that the existing structural system was adequate to meet both sets of standards and that no retrofit was required. The GSA and UFC standards required extensive review and interpretation of the reference documents. The GSA was very interested in keeping their anchor Department of Defense tenant in the building but needed to also keep costs reasonable to get congressional funding for the retrofit approved. Our analysis was able to save millions of dollars in potential retrofit measures by means of our use of advanced analytical methods and understanding of historical construction methods used in the 1960’s.
Our analysis was able to save millions of dollars in potential retrofit measures by means of our use of advanced analytical methods and understanding of historical construction methods used in the 1960’s.
Following on from our previous studies, this project received ARRA in 2010 funding to implement the façade overclad project. Given the introduction of the new UFC progressive collapse requirements in 2009, Hinman was tasked with performing a new analysis to evaluate whether the existing structure would meet the new criteria.
This progressive collapse analysis was performed using a nonlinear dynamic analysis with the software LS-DYNA. The approach followed the Alternate Path method for Occupancy Category III compliant with the UFC requirements. In addition, the structure’s first floor perimeter columns were analyzed for Enhanced Local Resistance (ELR) per the UFC criteria. In adherence with the UFC, the progressive collapse analysis was run for various column loss scenarios. A total of 41 analyses were run in addition to a number of sensitivity analyses in order to understand the effects of analysis variables such as connection capacities and damping.
Hinman found that the new UFC progressive collapse document is more conservative that the previous version because it now refers to ASCE 41 criteria. Of particular note was the connection capacity calculation procedure for one of the four governing limit states presented in ASCE 41 which was found to be conservative and governing the building performance. Hinman researched several other documents including the Federal Emergency Management Agency document (FEMA 274) and FEMA 355D in an effort to justify increased connection strength.