Abstract. This paper presents results of an experimental study for concrete column filled poly vinyl chloride (PVC) tubes confined by plain socket with 5.8 & 6.8 mm thicknesses, 102 mm diameter and 100 mm depth. The total of five concrete filled columns using PVC tubes (CFT PVC) was tested to investigate the columns' behaviour. The column is 700 mm height, 100 mm external diameter and 3.5 mm tube thickness with different thickness of plain socket. The results presented include maximum axial load, plain socket confinement effect, the mode of failure, and lateral PVC strain. The axial load enhancement of PVC-concrete columns confined using plain socket shows an increment of 21.3% up to 55.2% and axial strain from 21% to 40% compared with displacement for control composite columns at 192 kN ultimate load.

Abstract. This paper presents results of an experimental study for the shear strengthening of reinforced concrete (RC) deep beam using near surface mounted (NSM) carbon fiber reinforced polymer (CFRP) anchor bars. To ensure shear failure, five RC deep beam specimens were cast with nominal shear reinforcement. Shear strengthening of the RC deep beams was conducted by inserting 5 mm diameter by 450 mm length of CFRP bars as anchors with spacing of 100 mm and 150 mm centre to centre from the support of the beam. All RC beams were simply supported and subjected to a four-point bending test with shear span to effective depth ratio of 0.864. The results presented include the ultimate load, CFRP contribution to shear, modes of failure and the load-deflection profile. The shear enhancement of the RC deep beams shows an increment of 17.3% up to 25.5% with decreasing mid-span deflection from 6.4% to 15.1%. In addition, using this technique also increases its flexural beam resistance under the same conditions.

In this study, the Performance Based Design PBD method, which has been used only in seismic design by several codes, has been expanded to be applied to structures exposed to blast loads.The plastic hinge models used in PBD, which currently available for earthquake loads do not represent real behavior under the blast load. An analytical approach was proposed to represent the plastic behavior of flexural response under blast loads. The proposed model considers the following essential phenomena: concrete cover crushing, concrete core crushing, bar buckling in compression reinforcement, strain hardening in tensile reinforcement and softening in reinforcement bar. The proposed analytical approach has been validated with two experimental results of columns applied to blast loads and reasonable results has been seen KEYWORDS: Performance Based Design PBD, plastic hinge, concrete cover crushing, concrete core crushing, bar buckling, blast loads, nonlinear dynamic analysis. ASCE 41-13 PLASTIC HINGE MODEL VALIDATION UNDER BLAST LOADSASCE 41-13, 2013 assumed that the nonlinear load-deformation relation is based on experimental evidence or taken from specified tables showing deformation limits. The typical ASCE 41-13 load-deformation relation is shown in Fig. 1, where deformations are expressed using terms, such as strain, curvature, rotation or elongation. Generally, the typical plastic hinge model is described by Modeling Parameters MPs and Acceptance Criteria (Ghannoum. W. M., 2014). The parameters (a) and (b), which can be found from ASCE 41-13 refer to post-yield deformation or plastic deformation. When the load-deformation relation is used to express the flexural response, it is given as moment-rotation relation for the plastic hinge at a section.

This paper presents experimental results of four prismatic concrete reinforced beam and strengthened by NSM (Near surface mounted) FRP (Fiber Reinforced Polymer) reinforced technique, with additional roots planted in the concrete. The strengthening technique causes load capacity of beams to increase from (6%-8%).A decrease in mid-span deflection was also observed from (4%-5%).Using this technique gave increasing in flexural beam resistant under the same conditions and this increasing was also noted in shear beam resistant.

This paper is devoted to investigate the behavior of prestressed concrete beams under pure torsion using a non-linear three-dimensional finite element model. The 20-noded isoparametric brick elements have been used to model the concrete. The reinforcing bars are idealized as axial members embedded within the concrete element and perfect bond between the concrete and the reinforcement has been assumed to occur. The behavior of concrete in compression is simulated by an elasto-plastic work hardening model followed by a perfect plastic response, which is terminated at the onset of crushing. On the other hand the behavior in tension is simulated by implementing a smeared crack model in connection with using a tension-stiffening model that account for the retained post-cracking stresses, and a shear retention model that modifies the shear modulus of rigidity as the crack widens. Also a model to simulate the reduction in the concrete compressive strength in presence of tensile transverse straining has been implemented in this study. Two types of prestressed concrete beams under torsion have been analyzed and the finite element solutions were compared with the experimental data. Several parametric studies have been carried out  to investigate the effect some important material parameters. In general, good agreement between the finite element solutions and the experimental results was obtained.