Behavior of Glass Fiber–Reinforced Polymer Reinforced Concrete Continuous T-Beams

Abstract

In this study, a total of twelve beams continuous over two spans of 2,800 mm each were constructed and tested to failure. The beams were divided into two series. Series 1 included six T-beams under symmetrical loading, while Series 2 dealt with six rectangular beams under unsymmetrical loading conditions. In Series 1, the test variables included material type, assumed percentage of moment redistribution, spacing of lateral reinforcement in flange, arrangement of shear reinforcement, and serviceability requirements. In Series 2, three different loading cases were considered, I) loading both spans equally, II) loading both spans maintaining a load ratio of 1.5 and III) loading one span only. Under the loading case II, the parameters of reinforcing material type, assumed percentage of moment redistribution and serviceability requirements were investigated.The test results of both series showed that moment redistribution from the hogging to the sagging moment region took place in GFRP-RC beams which were designed for an assumed percentage of moment redistribution. In Series 1, the decrease of the stirrups spacing from 0.24d to 0.18d enhanced the moment redistribution percentage. Also, decreasing the spacing of lateral reinforcement in the flange from 450 to 150 mm improved the moment redistribution through enhancing the stiffness of the sagging moment region. In Series 2, the unsymmetrical loading conditions (loading case II and III) reduced the moment redistribution by reducing flexural stiffness in the heavily loaded span due to extensive cracking. Regarding serviceability in both series, the GFRP-RC beam designed for the same service moment calculated from the reference steel-RC beam, was able to meet the serviceability requirements for most types of the structural applications.ii ACKNOWLEDGEMENT

Simulation of dynamic mechanical and viscoelastic behavior in polymer/clay nanocomposites

“…By using Equations (2) and (3), the storage and loss moduli are expressed as Equations (4) and (5), respectively. The ratio of loss modulus to storage modulus is defined as loss factor (Tanδ).…”

“…Besides, the storage modulus of abovementioned nanocomposite was higher than those of pure polypropylene and polypropylene/glass composite. [5] Karipal et al added the nanoclay to epoxy/glass composite and observed that the tensile and flexural strengths and moduli increased. [6] Poly(butylene terephthalate) (PBT) is an important engineering thermoplastic, which due to its distinctive properties comprising high crystallization rate, excellent strength and stiffness, good creep and fatigue resistances, good thermal stability and electrical properties, is widely used in numerous applications.…”

Flexural Response of RC beams cast with normal and steel fibre concrete internally reinforced with various types of FRP bars

“…Due to FRP advantages compared to steel bars (high strength to weight ratio and durability), the use of FRP instead of steel as internal reinforcement for concrete elements has become increasingly common, especially in North America, as a means to avoid steel corrosion problems. Flexural behaviour of RC beams reinforced with FRP bars is investigated in previous researches [1][2][3][4][5][6][7][8][9][10]. Flexural ductility of RC elements with steel bars is calculated as the ratio of ultimate displacement to displacement at steel yield, while in the case of RC elements reinforced with FRP bars it can be calculated in a number of ways [11][12][13].…”

Flexural Response and Moment Redistribution of RC Continuous T-Beams Strengthened With FRP or Steel Bars

“…In the case where the failure of strengthened members is due to the NSM system failure, two different types of rupture are possible, the failure is due to the pull-out of the rods inducing almost splitting of the resin and concrete surrounding the groove or the peeling-off of the concrete covering the groove from the end of the rod [6]. Although many in situ RC beams are of continuous construction, there has been very little research into the behaviour of such beams [7][8][9][10][11]. However, moment redistribution in such elements was reported in previous studies [12][13][14][15][16][17][18][19].…”

“…Although many in situ RC beams are of continuous construction, there has been very little research into the behaviour of such beams [7][8][9][10][11]. However, moment redistribution in such elements was reported in previous studies [12][13][14][15][16][17][18][19]. The observed moment redistribution was attributed to the relatively low modulus of elasticity of the FRP bars, compared to that of steel bars, the plasticity of concrete at high-load levels and the different bond characteristics of the FRP bars, in addition to the difference in the flexural stiffness between the critical sections.…”