DeSimone Consulting Engineers, Chicago
The construction industry is in the midst of a tall concrete building boom unlike anything that has occurred in the last several decades. This presentation will discuss contemporary post-tensioning practices used in these tall concrete buildings. Included will be examples of several buildings designed by the author, as well as buildings designed by others. Issues discussed will include lateral design, the use of post-tensioning to increase building stiffness and control drift, two-way verses one-way slab systems, creative uses of post-tensioning to significantly increase slab spans in office and residential towers, the use of high-strength rebar to reduce congestion, and other topics of interest.
Case studies underlining the advantages of post-tensioned applications in various parts of the buildings from below grade level, to super long flat plate spans, and long cantilevers will be presented. Relatively thin flat plates in the order of 8 to 8.5 inches thick and spanning 40 to 45 feet were found beneficial in providing unobstructed views in residential applications and mitigating parking and layout conflicts. Additionally, case studies will examine the design and cost benefits of post-tensioning in adaptive re-use applications. Furthermore, the application of post-tensioning in floor plates to resist lateral wind forces will be presented as well.
The target audience includes design professionals from engineers to architects and contractors, university faculty members, and code enforcement officials. One of the key goals of this presentation is to increase awareness of the innovative and versatile use of post-tensioning in tall building design.