Partial Material Strength Reduction Factors: for ACI 318?

ABOUT THE INTERNATIONAL CONCRETE ABSTRACTS PORTAL

  • The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal

  


Title: Partial Material Strength Reduction Factors: for ACI 318?

Author(s): Tong Zhang and F. Michael Bartlett

Publication: Structural Journal

Volume: 116

Issue: 3

Appears on pages(s): 159-169

Keywords: beams; columns; design strength; moment; partial material strength reduction factors; reinforced concrete; reliability; slabs

Date: 5/1/2019

Abstract:
The strength reduction factors, , defined in ACI 318-14 for different structural actions and elements lead to inconsistent results. This study proposes partial material strength reduction factors for concrete, c, and reinforcing steel, s, that yield similar design strengths and more consistent reliability indexes. Two structural actions are investigated: moment, and combined moment and axial force. The first-order, second-moment method is used to compute reliability indexes for moment, and Monte Carlo simulation is used for combined moment and axial force. The recommended partial material strength reduction factors are s of 0.90 for slabs, beams, and both tied and spirally reinforced columns, and c of 0.60 for slabs, beams, and tied columns or 0.70 for spirally reinforced columns.