The Behavior of Hybrid Fiber-Reinforced Concrete Elements: A New Stress-Strain Model Using an Evolutionary Approach

Abstract

Several stress-strain models were used to predict the strengths of steel fiber reinforced concrete, which are distinctive of the material. However, insufficient research has been done on the influence of hybrid fiber combinations (comprising two or more distinct fibers) on the characteristics of concrete. For this reason, the researchers conducted an experimental program to determine the stress-strain relationship of 30 concrete samples reinforced with two distinct fibers (a hybrid of polyvinyl alcohol and steel fibers), with compressive strengths ranging from 40 to 120 MPa. A total of 80 % of the experimental results were used to develop a new empirical stress-strain model, which was accomplished through the application of the particle swarm optimization (PSO) tech-nique. It was discovered in this investigation that the new stress-strain model predictions are consistent with the remaining 20% of the experimental stress-strain curves obtained. Case studies of hybrid–fiber–reinforced concrete constructions were investigated in order to better understand the behavior of such elements. The data revealed that the proposed model has the highest absolute relative error (ARE) frequencies (ARE10 % and the lowest absolute relative error (ARE > 15 %) frequencies (ARE > 15 %).

The Combined Strengthening Effect of CFRP Wrapping and NSM CFRP Laminates on the Flexural Behavior of Post-Tensioning Concrete Girders Subjected to Partially Strand Damage

“…However, when the applied load exceeds the crack load, the sub-reference girders exhibit a significantly higher rate of stiffness degradation as a result of the reduction in the pre-stress force, and thus an increase in the rate of crack development, increasing deflection. Meanwhile, the flexuralstrengthening CFRP NSM laminates demonstrated their effectiveness in delaying the development of cracks and postponing the degradation of the strengthened girders' stiffness [16,17]. As a result, for the same level of applied load, the strengthened girders showed lesser deflection than the reference girders.…”

Improved Shear Strength Prediction Model of Steel Fiber Reinforced Concrete Beams by Adopting Gene Expression Programming

“…Over the past decade, structural engineering has seen a significant increase in the use of GEP. Many authors have used GEP to create models for estimating structural component capacities [ 19 , 20 , 21 ]. Recently, RC beam-column joints have been successfully predicted using GEP [ 6 ], especially when the design code formulations are unavailable.…”

“…Shahnewaz and Alam [ 18 ] have identified various influencing parameters, which are incorporated in a genetic algorithm-based equation for steel fiber reinforced (SFRC) concrete beams. Although all these artificial intelligence models show satisfactory accuracy, the database employed to generate these modes is relatively small [ 19 , 20 , 21 ]. One other important issue that remains with these models is that they do not consider the mechanical properties of steel fibers.…”

Flexural Strengthening of Prestressed Girders with Partially Damaged Strands Using Enhancement of Carbon Fiber Laminates by End Sheet Anchorages

“…The stiffness of the reference girders decreases slightly and the strengthened girders did not significantly differ from the damaged reference girders of the same group. When the applied load exceeded the cracking load, the damaged members exhibited a relatively high rate of stiffness deterioration [8] due to the absence of a portion of the pre-stressing force, which increases the development rate of crack and displacement. Likewise, the flexural-strengthening CFRP EB of the laminates exhibited their ability to postpone the fracture formation and deterioration of the stiffness of the strengthened girders [9], and the girders strengthened with laminates and anchors were observed to be superior to the girders strengthened with laminates only.…”