ACI Foundations CRC releases two research products

Farmington Hills, Mich. — The Concrete Research Council (CRC), a subsidiary of the ACI Foundation, announced two new research products: Interface Shear Transfer of Lightweight Aggregate Concretes with Different Lightweight Aggregates and Evaluation of Seismic Performance Factors and Pedestal Shear Strength in Elevated Water Storage Tanks. Both advance the knowledge and sustainable aspects of the concrete industry in conjunction with the efforts of select ACI technical committees.

Lesley Sneed of Missouri University of Science and Technology and principle investigator of Interface Shear Transfer of Lightweight Aggregate Concretes with Different Lightweight Aggregates tested applied shear force-slip relations, peak shear strength, and examined the current shear-friction design provisions in ACI 318 "Building Code Requirements for Structural Concrete," and the Precast/Prestressed Concrete Institute PCI Design Handbook. The findings from this research proposed revisions to the next edition of the ACI 318 code and PCI Design Handbook for shear-friction design provisions of a smooth interface condition. The result also submitted that for cold joint smooth interface conditions, the current formula found in ACI 318 and the PCI Design Handbook should be updated to allow for more accurate and economical designs.

“The research completed by this product will move the building code forward,” stated Lesley Sneed, FACI. “It demonstrates a needed next step in allowing for more efficient structural designs.” The project was supported by ACI-ASCE Joint Committee 445, Shear and Torsion, and was sponsored by the Precast/Prestressed Concrete Institute and the ACI Foundation’s Concrete Research Council.

Principle Investigator Reza Kianoush from Ryerson University led Evaluation of Seismic Performance Factors and Pedestal Shear Strength in Elevated Water Storage Tanks. The project evaluated the current code-recommended values for response modification factors along with pedestal shear strength for design of single-pedestal elevated concrete and composite steel-concrete water storage tanks. This project focused on two distinct research goals. The first was the investigation of the ACI 371E-08 equation for nominal shear strength of reinforced concrete pedestals and the effect of axial compression in enhancing the shear strength of the reinforced concrete pedestals. Second was the study of the effect of wall opening on the non-linear behavior of elevated water tanks.

The research was meant to:

• Propose response modification factors for seismic design of single pedestal elevated concrete and composite steel-concrete water storage tanks to include in ACI 371 and ACI 350.3 standards; and
• Quantify and include the effect of axial load in the current equation of nominal shear design of a pedestal.

“The information and data from this research will help to protect a valuable resource in areas with seismic activity,” stated Kianoush. “Updating the current design standards to better protect a water supply is an incredibly valuable endeavor.” This project was supported by ACI Committee 371, Elevated Tanks with Concrete Pedestals, and ACI Committee 350, Environmental Engineering Concrete Structures, and was sponsored by the ACI Foundation’s Concrete Research Council.