Shear strength of steel fibre reinforced concrete beams with stirrups

Data-driven shear strength prediction of steel fiber reinforced concrete beams using machine learning approach

Even though the structural behavior steel fiber reinforced concrete (SFRC) has been extensively researched, structural applications are still limited. One barrier to its implementation is the lack of mechanical models that describe the behaviour of SFRC members failing in shear. This paper reviews the effect of steel fibers on the different mechanisms of shear transfer and combines the observations from the literature regarding the parameters that affect the shear capacity of SFRC. Additionally, a selection of currently available expressions for the shear capacity of SFRC is presented. This paper reviews the current state-of-the-art on the shear capacity of SFRC elements without shear reinforcement, shows the lacks in our current understanding on the shear behaviour of SFRC elements without shear reinforcement, and outlines the steps necessary to address these lacks. The presented work aims to be a framework for (experimental) efforts addressing the shear capacity of SFRC members without shear reinforcement.

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How do steel fibers improve the shear capacity of reinforced concrete beams without stirrups

This study is focussed on the performance evaluation of built-up cold-formed steel (CFS) columns under monotonically increasing axial compression loading. Five test specimens of built-up columns were fabricated using four CFS angle sections connected by single lacing systems. Width-to-thickness ratios and slenderness ratios of chord and lacing elements, and height of columns were varied in the test specimens. Column strengths, axial load vs. displacement response, mode of failure, and deformed configurations were the main parameters evaluated in the experimental investigation. In addition, a numerical study was conducted to predict the behaviour of laced built-up CFS columns using a finite element software ABAQUS. The developed numerical models were validated using the test results. Test results were used to develop the column strength curves for built-up laced CFS columns. Finally, the results of this study were compared with the design strength predictions by North American Standards and European Standards for CFS sections.

Behaviour of laced built-up cold-formed steel columns: Experimental investigation and numerical validation

In this study, twelve reinforced concrete (RC) T-beams were tested to failure under two-point flexural loading to investigate the influence of shear span-to-effective depth (a/d) ratio on their ultimate resistance and failure modes. All test specimens had exactly same cross-section and longitudinal steel ratio without any transverse stirrups along their lengths. The percentage of steel fibers used in the concrete mix ranged from 0 to 1.5 %, whereas the values of a/d ratio were varied as 1.6, 2.5 and 3.0 for each case. Steel fiber reinforced concrete (SFRC) specimens exhibited the higher ultimate resistance, displacement ductility and flexural toughness as compared to the RC beams without steel fibers for all values of a/d ratio. The diagonal-tension (shear) mode of failure is noticed in the RC specimen for the a/d ratio of 3.0, whereas the flexural mode of failure is noticed for the SFRC specimen with 1 % steel fibers for the a/d ratio of 1.6. The flexural strengths of SFRC specimens as noted in the experiments are compared with the theoretical values predicted using the ultimate design approach.

Experimental study on shear-span to effective-depth ratio of steel fiber reinforced concrete T-beams

Monotonic behavior of large-scale SFRC beams without stirrups

Legendre wavelet collocation method for fractional optimal control problems with fractional Bolza cost

Collocation method for solving nonlinear fractional optimal control problems by using Hermite scaling function with error estimates

Limiting values of slenderness ratio for circular braces of concentrically braced frames

Cold-formed steel members are used as structural members in a wide range of applications because of their simpler fabrications and high strength-to-weight ratios. Though high width-to-thickness ratio of such sections make them vulnerable to local buckling under compressive stresses, past studies have shown that these members possess inelastic reserve strengths at the ultimate stage under flexural loading. This study explore the influence of width-to-thickness ratio, lip lengths and depth-to-width (aspect) ratio on the ultimate flexural strengths of cold-formed channel sections bending about their minor axes. Finite element (FE) analyses have been conducted on 216 numbers of channel sections with varying geometric properties to investigate their ultimate resistance and mode of failure under flexural loading. The ultimate flexural strengths of these sections are theoretically predicted using the current code provisions and are compared with the exact values obtained from FE analyses. An experimental investigation has also been performed on five specimens of channel sections with and without lips to validate the FE analyses results. Based on the analysis and experimental results, the limiting values of lip lengths, aspect ratios, and width-to-thickness ratios of channel sections are discussed.

Nitin Kumar

Papers

Monotonic behavior of large-scale SFRC beams without stirrups

Legendre wavelet collocation method for fractional optimal control problems with fractional Bolza cost

Collocation method for solving nonlinear fractional optimal control problems by using Hermite scaling function with error estimates

Limiting values of slenderness ratio for circular braces of concentrically braced frames

Optimization of lip length and aspect ratio of thin channel sections under minor axes bending