Papers by Keyword: Reinforced Concrete Beam

Abstract: This experimental study has been conducted on the efficiency of epoxy-bonded hemp fiber reinforced polymer (FRP) composites in flexural strengthening of reinforced concrete (RC) beams. A total of five RC beams were cast and tested up to failure. The test parameters included fiber thickness and strengthening configuration. The experimental results show the capability of hemp FRP composites to increase the loading capacity in flexure of RC beams compared with the un-strengthened beam. The enhancement of ultimate load becomes more significant as the fiber thickness is increased. The effectiveness of strengthened beams in U-wrapped scheme is found greater than strengthened beams in bottom-only scheme. Based on results, it indicates that hemp FRP has a potential to considerably increase the strength and stiffness of the original RC beam.

Abstract: This paper presents an experimental study on the strengthening of scaled reinforced concrete (RC) deep beam using hemp fiber reinforced polymer (HFRP) composite. HFRP is the composite material which compose of hemp fiber bonding with epoxy resin. The major benefit of using hemp fiber is that their low price, high toughness, and hemp is natural fiber product which that can be found locally. In this study 2 different fiber orientation has been apply to scaled deep beam and also different in thickness (fiber layer). Three scaled deep beam were strengthened using HFRP composite, remaining one beam was tested as control (unstrengthen) beam. The test result show that HFRP composite are effective to enhance ultimate load capacity for RC beam. The HFRP composite applied in U-Shape was result into higher ultimate load compare with the sample that applied with both side strengthen method

Abstract: Oil palm clinker is formed by burning of oil palm kernel shell and fibrous materials in boiler furnace. The clinker is no longer a bio-material that has changed to inert material likes the crushed brick. Large quantities oil palm clinkers have become a waste and caused disposal problem. It requires extra costs for handling, transportation and finding out suitable the dumping site. Research has been conducted to explore the potentiality usage of oil palm clinker as fine and coarse lightweight aggregates at Universiti Pertanian Malaysia. Mixtures of oil palm clinker concretes were designed, prepared and tested. Mechanical properties of a good mixture of tensile strength, compressive strength, modulus of elasticity, creep and shrinkage were satisfied the standard engineering codes of practices. Oil palm clicker concrete was found lighter than conventional concrete, which usually weighs between 2240 and 2400 kg m^-3. The means of compressive and tensile strengths were found 30.79 and 3.34 N mm^-2 respectively. In addition, the mean of modulus of elasticity was 13.024 kNmm^-2. Therefore, oil palm clinker aggregate and concrete are recommended to be used in lightweight reinforced concrete structures.

Abstract: Oil palm clinker is made from waste burning of oil palm shell and the fibrous material in oil palm mill. The clinker has changed into permanent state, which is no longer a bio-material after undergone high temperature burning process. Large quantities of various sizes of oil palm clinker wastes have become disposal constraints. It requires extra costs for handling, transporting and searching out the suitable dumping sites. Study was found that the clinker is lightweight and satisfactorily achieved compressive strength to make lightweight concrete structure. Several lightweight oil palm clinker concrete beams were designed and tested according to British standard Code of Practices. The results shows the provision can be conservatively used to design the lightweight oil palm clinker concrete beam reinforced with deformed bar. Experimental loads were found higher than the design loads for all the tested beams. Therefore, the equation used to calculate ultimate load is safe and satisfactory.

Abstract: An experimental investigation on laboratory simulation of reinforced concrete beams submerged in sea water was carried out. The research aimed to analyze the beam flexural behavior cause by submersion effect in the marine environment and simulation pool. Flexural testing was conducted by using two point loading up to beams ruptured. Total 18 reinforced concrete beams of 10 cm x 12 cm x 60 cm in dimension with GFRP-S bonded on the bottom side. Nine beams were submerged in the marine environment and 9 beams were submerged in the simulation pool. Exposure period is 1, 3 and 6 months after 28 days cured in fresh water. The result indicate that the ultimate load and bonding capacity of beam specimens submersed in the marine environment were relatively lower than the specimens submersed in simulation pool. Based on this experimental study, submerging of specimens in simulation pool (Pp) could be used to predict specimens submersed in marine (Ps) by using equation

Abstract: When reinforced concrete (RC) beams are found deficient in flexure, and fails in shear capacity after shear strengthening, the need to use new technique for flexure strengthening become important. Over the years, there are many experimental studies had been carried out with this technique of strengthening, and finding from other researchers have proved to be effective and successful. In this study, the behavior of flexure in RC beams strengthened with carbon fiber reinforced polymer (CFRP) were investigated. ANSYS11 software package of finite element method was use to simulate two models of RC beams with different parametric study such as (i) effect of grade of concrete, (ii) number of layers of CFRP strips, (iii) effect of steel stirrups and CFRP strips and (iv) longitudinal reinforcement yield stress. The results show that for beams strengthened with CFRP has increased in capacity load up to 32.8%. In general, good agreement between the FE solution and the available experimental results has been obtained.

Abstract: Inner transverse prestressed bars were used to enhance the shear capacity of concrete beams in this paper, which can be used in transformer beams to reduce the sectional size. Two transversely prestressed one ordinary concrete beams were tested and calculated by finite element method, and the following conclusions can be drawn: (a)The shear capacity of transversely prestressed concrete beam increase rapidly with the increase of the prestressing force level, which means that prestressing force level has a great influence on the shear capacity of transversely prestressed concrete beam. (b) The transverse prestressing bars can efficiently enhance the anti-crack performance of the reinforced concrete beams.

Abstract: First, a fire test on concrete beams was carried out. Then after the static test of simply supported beam, the phenomena of simply supported beamsbefore and after fire were compared in order to determine the damage degree ofmechanical property. Finally, the width reduction method was proposed tocalculate the stiffness of beam after fire. And the formula applied toengineering practice was also deduced. The comparison of calculation resultsand experimental results was in a good agreement.

Abstract: This paper deducing the analytical solution of temperature stress of reinforced concrete beams strengthened under the principle of compatibility of deformation. And we also analyze the influencing factors, such as elasticity modulus, thickness, coefficient of thermal expansion, the height of test beam, concrete mark and so on. The research shows that the elasticity modulus and thickness of the carbon fiber are the major influencing factors of temperature stress, the coefficient of thermal expansion and the height of test beam are the second influencing factors, and the influence of concrete mark is very tiny.

Abstract: Side-strengthened reinforced concrete or precast prestressed concrete beam for inadequate seismic performance is proposed in this paper. The factors are simulated by ABAQUS software for the impact of seismic performance, which are difference of material strength grade, initial load and the order of prestressing and pretightening. The strengthening technology can improve the seismic performance of side-strengthened beam. The meterials with different strength grades which used for beams give full play to their role. The initial load has little effect on the seismic performance. The way of prestressing after pretightening plays a favorable effect for the seismic performance. The simulation results can accurately reflect the impact of these factors on the side-strengthened beam.