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: Design of Deep Pile Caps by Strut-and-Tie Models

Author(s): Perry Adebar and Luke (Zongyu) Zhou

Publication: Structural Journal

Volume: 93

Issue: 4

Appears on pages(s): 437-448

Keywords: building codes; caps (supports); deep beams; footings; piles; reinforced concrete; shear strength; structural design; strut-and-tie models; tests.

DOI: 10.14359/9703

Date: 7/1/1996

Abstract:
Comparisons with results from 48 pile cap tests demonstrate that the one-way shear design provisions of the present ACI Building Code are excessively conservative for deep pile caps, and that the traditional flexural design procedures for beams and two-way slabs are unconservative for pile caps. Flexural design can best be accomplished using a simple strut-and-tie model, and test results demonstrate that the longitudinal reinforcement should be concentrated over the piles as suggested by strut-and-tie models. A simple shear design procedure is proposed in which maximum bearing stress is considered the best indicator of shear strength for deep pile caps. The maximum bearing stress that can be applied without causing splitting of compression struts within pile caps depends on the amount of confinement, as well as the aspect ratio (height-to-width) of compression struts. The influence of confinement is more gradual than suggested by the ACI Code bearing strength provisions.