Title: Experimental Validation of Strut-and-Tie Method for Complex Regions

Author(s): Daniel Kuchma, Sukit Yindeesuk, Thomas Nagle, Jason Hart, and Heui Hwang Lee

Publication: Structural Journal

Volume: 105

Issue: 5

Appears on pages(s): 578-589

Keywords: design; detailing; strut-and-tie; validation

DOI: 10.14359/19941

Date: 9/1/2008

Abstract:
The strut-and-tie model (STM) of ACI 318-02 introduced new Code provisions for the design of regions in concrete structures that are subjected to complex states of stress. These provisions assume that the structure is sufficiently ductile to support the load in the manner envisioned by the designer. This assumption and the associated ACI Code provisions have only been properly validated by tests on structures with a few truss members, such as by tests on deep beams. This paper presents the results from three sets of STM validation experiments on more complex D-regions in which each region was designed by multiple strut-and-tie models that had up to 37 members and were statically indeterminate. Whereas the results indicate that the use of the STM approach and ACI 318-02 provisions lead to conservative designs, the examination reveals potential concerns over service level performance and the applicability of the STM for the design of very complex D-regions.