Title: Shear Strength Prediction of Deep CFFT Beams

Author(s): I. Ahmad, Z. Zhu, A. Mirmiran, and A. Fam

Publication: Symposium Paper

Volume: 230

Issue:

Appears on pages(s): 1085-1102

Keywords: concrete; deep beam; FRP; shear; strut-and-tie model

DOI: 10.14359/14882

Date: 10/1/2005

Abstract:
Despite significant theoretical advances in the use of concrete-filled fiberreinforced polymer (FRP) tubes (CFFT), research on their shear behavior has been fewand limited. Current method of shear analysis of CFFT beams relies on Bernoulli beamtheory, which utilizes the basic assumption of linear strain distribution across thedepth. Most recently, the use of modified compression field theory was suggested toimprove the shear analysis of CFFT beams. The approach, however, is not applicable tothe disturbed or D-regions of a beam, such as those in a deep CFFT beam. Therefore,this study adopted the strut-and-tie model to predict the shear strength of deep CFFTbeams. The model is validated against test results for a CFFT beam with a shear-span-to-depth ratio of 1. A parametric study is then carried out to assess the shear criticalityof CFFT beams. The study showed that shear failure would only be critical for beamswith shear span less than their depth. High strength concrete was also found toimprove capacity of CFFT beams. However, a judicious selection of concrete strengthand fiber architecture with different proportions of shear and flexural capacities of thetube could help optimize the use of materials.