Sources: Precast/Prestressed Concrete Institute, Chicago; CP staff
The American Society of Civil Engineers has presented the Charles Pankow Award for Innovation to PCI, whose “Seismic Design Methodology for Precast Concrete Diaphragms” project addresses engineering obstacles—rooted in structural member-to-member or member-to-shear wall connections—to precast concrete solutions in high seismic zone markets.
“This project was successfully completed because of exceptional collaboration between academia and industry,” says PCI Vice President, Technical Services Roger Becker, P.E. “Its completion and codification of the results means that engineering professionals can now use precast concrete diaphragms with confidence in any seismic zone. PCI is committed to conducting leading edge research that benefits our members, the precast concrete industry, and the built environment as a whole.”
Jointly funded by PCI, the National Science Foundation, Network for Earthquake Engineering Simulation, and Charles Pankow Foundation, the project represents a comprehensive seismic design methodology for precast concrete diaphragms connecting horizontal members to each other or shear walls. The research behind Diaphragm Seismic Design Methodology (DSDM) integrates finite element analyses of a diaphragm with full-scale reinforcing detail experiments and shaking table system tests. Findings resulted in the adoption of a revised force demand and resistance methodology for precast concrete diaphragms in 2015 NEHRP and ASCE/SEI 7-16.
DSDM is performance-based and possesses key features that address these aspects of behavior:
- Diaphragm seismic design forces more accurately reflecting the actual inertial forces that develop during strong shaking;
- Rational methods of determining diaphragm internal forces;
- Inelastic deformation capacity requirements for the diaphragm reinforcement;
- Protection of potentially non-ductile elements in the precast concrete diaphragm though the use of capacity design concepts; and,
- Explicit inclusion of diaphragm flexibility in drift limits checks.
Named for the California design-build contractor who advanced precast and cast-in-place concrete practice, the Charles Pankow Award for Innovation was established by the ASCE-affiliated Civil Engineering Research Foundation in 1996. It recognizes organizations working collaboratively to advance the design and construction business, and was instituted as an ASCE award in 2008.