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Title: Experimental Study of Drilled-Shaft Footings Under Uniaxial Flexural Compression Designed with Different Column Reinforcement Anchorages

Author(s): Yi

Publication: Web Session

Volume: ws_S22_Yi.pdf

Issue:

Appears on pages(s):

Keywords:

DOI:

Date: 3/28/2022

Abstract:
This study is a part of comprehensive research to improve strut-and-tie modeling and design guidelines for drilled shaft footings. This experimental study compares the anchorage behavior of the column reinforcement of different anchorage types embedded in the drilled shaft footing subjected to uniaxial flexural compression inducing tension in one side of the column and non-uniform compression in drilled shafts. The corresponding 3D strut-and-tie model has vertical ties at the column reinforcement locations. The column ties are connected with smeared nodes of which nodal geometry cannot be clearly defined; therefore, the extended nodal zone concept is not applicable for the anchorage check of the column reinforcement. In addition to this ambiguity, a lack of experimental research conducted for drilled shaft footings under uniaxial flexural compression leads to using 90-degree hooks to anchor the column reinforcing bars within drilled shaft footings in practice without any research basis. In this study, large-scale tests on four drilled shaft footing specimens were conducted to investigate the effects of different anchorage types of the column reinforcement (straight, headed, and two 90-degree hooked reinforcement with different orientations) on the anchorage behavior of the column reinforcement. The test results showed that the properly-oriented hooked reinforcement considering the internal force flow of the strut-and-tie model developed a relatively uniform stress distribution throughout its length than the other anchorage types.