Tension stiffening approach for deformation assessment of flexural reinforced concrete members under compressive axial load

Abstract

The deformation characteristics of cracked reinforced concrete beams are largely dependent on the tension stiffening effect. As one of the serviceability analysis approaches, the employment of a concrete tensile stress block that reflects the flexural tension stiffening behavior is useful for evaluation of beam deflections. In many practical applications, however, beams have to withstand a small degree of axial compression. There has been little research on axial load effects on tension stiffening, and tensile stress block for beams subject to compressive axial load has not been developed. In this study, finite element method is employed to analyze beams under different levels of compressive axial load. The numerical results reveal that the tensile stress block is considerably influenced by the presence of axial load. Using the tension stress fields obtained, values of stress block parameters under different levels of axial load are determined. Adequacy of the proposed model was verified using the test data reported in the literature.

An experimental assessment of corrosion damage and bending capacity reduction of singly reinforced concrete beams subjected to accelerated corrosion

“…In a cracked RC member, this effect is explained by the contribution of the concrete in-between the cracks to carrying tensile stresses. As a result, the RC member behaves stiffer than a bare rebar and shows the formation of multiple closely spaced cracks [22,23]. A study on corroded beams, done by Castel et al [24,25], has indicated that the coupling effect of cross-section loss and bond deterioration contributes to the overall bending stiffness and capacity of the beam.…”

Investigating the Flexural Behavior of a Two-Span High-Performance Concrete Beam Using Experimentally Derived Stress Block Parameters

“…Designing HPC beams to withstand flexure can be a challenging task, as most standard codes and methods used for NSC cannot be applied to HSC. , To study the flexural behavior of higher-strength concretes, researchers have put forward stress block parameters and verified their experimental results, proposing substantial changes to current codes. − Stress block parameters have also been proposed for special types of concretes, such as geopolymer concrete (GPC). , However, it is unclear whether these parameters can be applied to HPC. While the ultimate strain of concrete recommended by the American code 441-R96 is 0.003, other codes such as EC-2, Canadian code, and IS Code limit it to 0.0035.…”

Strengthening of beams or slabs using temperature induction

“…Then, active steering of constraint moments using temperature induction is presented. The focus is set on nonlinear materials such as cracked RC, which require a realistic estimation of stiffness distribution to set the temperature gradient 27,28 . Finally, the method is experimentally verified on a two‐span RC girder strengthened at its internal support.…”