No 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 %).

A few examinations have endeavored to assess a definitive shear quality of a fiber fortified polymer (FRP)- strengthened solid shallow shafts. Be that as it may, need data announced for examining the solid profound pillars strengthened with FRP bars. The majority of these investigations don't think about the blend of the rigidity of both FRP support and cement. This examination builds up a basic swagger adequacy factor model to evaluate the referenced issue. Two sorts of disappointment modes; concrete part and pulverizing disappointment modes were examined. Protection from corner to corner part is chiefly given by the longitudinal FRP support, steel shear fortification, and cement rigidity. The proposed model has been confirmed utilizing an aggregate of 45 databases gathered from writing. Results show that the proposed model can evaluate a definitive shear quality. Structure of trial (DOE) programming was used to examine the impact of different parameter esteems on a definitive shear quality limit. The outcomes demonstrate that the shear range to powerful profundity proportion has the most astounding impact contrasted and alternate parameters.

This paper shows how the inclination angle affects the stiffness and strength of RC columns. Experimental work of two scaled-down vertical columns with a length of 1000 and 1250mm was achieved to provide data for subsequent validation of analytical and numerical finite element solutions. The analytical solution is based on current design assumptions while the numerical solution adopts a sophisticated FE simulation with three-dimensional elements for the concrete mass and link element for the rebars. The rebars are assumed to be fully bonded in the FE model. Hooke’s law and Damaged Plasticity models are respectively used to simulate the elastic and inelastic behavior of the concrete, whereas the elastic perfectly plastic model is proposed for the rebars’ behavior. Subsequently, the validated FE model is used to investigate the response of two inclined columns with a length of 1000mm and 1250mm. Three inclination angles of 5°, 7.5° and 10° are considered for each length. FE results indicate that column inclination reduces its axial stiffness and strength. A strength reduction ratio of about 0.8% up to 3.4% is noted for inclination angles of 5° to 10°. It is also noted that the longer column is more sensitive to the inclination angles.

This paper studies the effect of mean wind velocity on tall building. Wind velocity, wind profile and wind pressure have been considered as a deterministic phenomenon. Wind velocity has been modelled as a half-sinusoidal wave. Three exposures have been studied B, C, and D. Wind pressure was evaluated by equation that joined wind pressure with mean wind velocity, air density, and drag coefficient. Variations of dynamic load factor for building tip displacement and building base shear were studied for different building heights, different mode shapes, different terrain exposures, and different aspect ratios of building plan. SAP software, has been used in modelling and dynamic analysis for all case studies. Results For different building heights considered maximum dynamic load factor (DLF) occurs in height range from 100-150m because fundamental building frequency is so close as to dominate wind frequency. Effects of higher modes become insignificant for height greater than 175m. Effect of three different terrain exposures B, C, and D on DLF for tips displacement and building base shear have been insignificant effect on response of tip displacement and building base shear. . Finally, effect of aspect ratio  for different building heights with dynamic load factor (DLF) for tips displacement and for building base shear have  approaching 2, fundamental building frequency is so closed to dominate wind frequency.