First Responders for the Built Environment

The presentation, through case studies, talks about emergency response services for structural issues encountered during construction of new design projects. Among other examples is an eleven story precast parking structure. The contractor observed significant diagonal faulted cracking of L-beams (supporting double-tee sections) near bearing locations, few days after pouring topping slab. In addition, inverted-tee girders were observed to be supported on cracked corbels at other locations. A quick turn around was required to mitigate any immediate life safety hazard posed by the structural distresses and buy time for thorough investigation, non-destructive testing, analyses, and repair design. Another example is a seven story precast parking structure. The structure was under construction and reportedly erected out of plumb. Poor concrete placing practices and poor weld detailing led to widespread cracking in multiple structural elements throughout the structure. A thorough condition appraisal of the entire structure, qualitative repair design and construction monitoring program were employed to tackle the observed distresses.

Presentation Learning Objectives:

1. Introduction to emergency response services in a forensic restoration project
2. A brief discussion on the qualitative and quantitative approach to mitigating immediate life safety hazard posed by structural distresses
3. Case studies that discuss the approach taken to tackle distresses in new construction, including:
   1. codes and standards referred;
   2. design assumptions made;
   3. field testing conducted;
   4. qualitative and quantitative analyses performed
4. The necessity of providing repair construction monitoring to evaluate conformance with construction documents