scholarly journals Flexural Behaviour of RC Beams Strengthened with Prestressed CFRP NSM Tendon Using New Prestressing System

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Woo-tai Jung ◽  
Jong-sup Park ◽  
Jae-yoon Kang ◽  
Moon-seoung Keum ◽  
Young-hwan Park
Keyword(s):  
Maximum Load ◽  
Experimental Results ◽  
Rc Beams ◽  
Failure Model ◽  
Anchor Plate ◽  
Flexural Behaviour ◽  
Bond Failure ◽  
Existing Structures ◽  
Effective Depth ◽  
Section Analysis

CFRP has been used mainly for strengthening of existing structures in civil engineering area. Prestressed strengthening is being studied to solve the bond failure model featuring EBR and NSMR methods. The largest disadvantage of the prestressing system is that the system cannot be removed until the filler is cured. This problem lowers the turning rate of the equipment and makes it limited to experiment, which stresses the necessity of a new prestressing system. Therefore, the present study applies a new prestressing system which reliefs the need to wait until the curing of the filler after jacking to the prestressing of NSMR and examines the effect of the prestressing size and location of the anchorage on the strengthened behaviour. The experimental results show that the crack and yield loads increase with higher level of prestress, while the ductility tends to reduce, and the anchor plate should be installed within the effective depth ds to minimize the occurrence of shear-induced diagonal cracks. The comparison of the experimental results and results by section analysis shows that the section analysis could predict the maximum load of the specimens strengthened by prestressed NSMR within an error between 4% and 6%.

Experimental Investigation on the Shear Behaviour of Concrete Beams Reinforced with GFRP Reinforcement Bars

2012 ◽  
Vol 626 ◽  
pp. 559-563 ◽  
Author(s):  
Azlina Abdul Hamid Noor ◽  
Ibrahim Azmi ◽  
Thamrin Rendy ◽  
Abdul Hamid Hanizah
Keyword(s):  
Concrete Beams ◽  
Experimental Results ◽  
Fiber Reinforced Polymer ◽  
Shear Behaviour ◽  
Rc Beams ◽  
Shear Cracks ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Effective Depth ◽  
Gfrp Reinforcement

This paper presents the experimental results of shear behaviour on concrete beams longitudinally reinforced with glass fiber-reinforced polymer (GFRP) reinforcement bars. Totally sixteen concrete beams were tested under static load. Half of the tested beams were longitudinally reinforced with GFRP reinforcement bars, while, the other half were reinforced with conventional steel reinforcement bars. The beams were prepared with varying test variables, such as shear span-to-effective depth ratios (a/d), amount and types of longitudinal reinforcement bars and stirrup spacing. The experimental results show that the ratios of a/d and stirrup spacing significantly influence the ultimate capacities of the beams. Moreover, more closely spaced diagonal shear cracks were resulted in GFRP reinforced concrete (RC) beams compared to steel RC beams.

Experimental Study of Ductile Fracture for Non-Aligned Multiple Flaws in a Plate

2009 ◽  
Author(s):  
Katsumasa Miyazaki ◽  
Kunio Hasegawa ◽  
Koichi Saito ◽  
Bostjan Bezensek
Keyword(s):  
Experimental Study ◽  
Ductile Fracture ◽  
Estimation Procedure ◽  
Maximum Load ◽  
Experimental Results ◽  
Collapse Load ◽  
Plate Specimen ◽  
Fracture Tests ◽  
Almost All

The fitness-for-service code requires the characterization of non-aligned multiple flaws for the flaw evaluation, which is performed using a flaw proximity rule. Worldwide almost all codes provide own proximity rule, often with unclear technical bases of the application of proximity rule to ductile fracture. To clarify the appropriate proximity rule for non-aligned multiple flaws in fully plastic fracture, fracture tests on flat plate specimen with non-aligned multiple through wall flaws were conducted at ambient temperature. The emphasis of this study was put on the flaw alignment rule, which determines whether non-aligned flaws are treated as independent or aligned onto the same plane for the purpose of flaw evaluations. The effects of the flaw separation and flaw size on the maximum load were investigated. The experimental results were compared with the estimations of the collapse load using the alignment rules in the ASME Section XI, BS7910 and API 579-1 codes. A new estimation procedure specific to the fully plastic fracture was proposed and compared with the comparison with the experimental results.

Comparison of flexural capacity of different hollow slab beams with/without pavement layer reinforced by steel plates

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Long Liu ◽  
Lifeng Wang ◽  
Ziwang Xiao
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Steel Plate ◽  
Plate Thickness ◽  
Experimental Results ◽  
Nonlinear Material ◽  
Finite Element Models ◽  
Rc Beams ◽  
Flexural Capacity ◽  
Content Type

PurposeReinforcement of reinforced concrete (RC) beams in-service have always been an important research field, anchoring steel plate in the bottom of the beams is a kind of common reinforcement methods. In actual engineering, the contribution of pavement layer to the bearing capacity of RC beams is often ignored, which underestimates the bearing capacity and stiffness of RC beams to a certain extent. The purpose of this paper is to study the effect of pavement layer on the RC beams before and after reinforcement.Design/methodology/approachFirst, static load experiments are carried out on three in-service RC hollow slab beams, meanwhile, nonlinear finite element models are built to study the bearing capacity of them. The nonlinear material and shear slip effect of studs are considered in the models. Second, the finite element models are verified, and the numerical simulation results are in good agreement with the experimental results. Last, the finite element models are adopted to carry out the research on the influence of different steel plate thicknesses on the flexural bearing capacity and ductility.FindingsThe experimental results showed that pavement layers increase the flexural capacity of hollow slab beams by 16.7%, and contribute to increasing stiffness. Ductility ratio of SPRCB3 and PRCB2 was 30% and 24% lower than that of RCB1, respectively. The results showed that when the steel plate thickness was 1 mm–6 mm, the bearing capacity of the hollow slab beam increased gradually from 2158.0 kN.m to 2656.6 kN.m. As the steel plate thickness continuously increased to 8 mm, the ultimate bearing capacity increased to 2681.0 kN.m. The increased thickness did not cause difference to the bearing capacity, because of concrete crushing at the upper edge.Originality/valueIn this paper, based on the experimental study, the bearing capacity of hollow beam strengthened by steel plate with different thickness is extrapolated by finite element simulation, and its influence on ductility is discussed. This method not only guarantees the accuracy of the bearing capacity evaluation, but also does not require a large number of samples, and has certain economy. The research results provide a basis for the reinforcement design of similar bridges.

Effects of Fibres on the Flexural Behaviour of Sound and Damaged RC Beams

2020 ◽  
pp. 423-432
Author(s):  
Raúl L. Zerbino ◽  
María C. Torrijos ◽  
Graciela M. Giaccio ◽  
Antonio Conforti
Keyword(s):  
Rc Beams ◽  
Flexural Behaviour

scholarly journals Torsional Strengthening of Low-Strength RC Beams with Post-Tensioned Metal Straps: An Experimental Investigation

2020 ◽  
Vol 17 (12) ◽  
pp. 1399-1411
Author(s):  
Monthian SETKIT ◽  
Thanongsak IMJAI ◽  
Udomvit CHAISAKULKIET ◽  
Reyes GARCIA ◽  
Komsan DANGYEM ◽  
...  
Keyword(s):  
Failure Modes ◽  
Beam Current ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Control Beam ◽  
Torque Capacity ◽  
Low Strength ◽  
Conservative Values ◽  
Post Tensioned

This article investigates the behaviour of low-strength reinforced concrete beams under pure torsion with and without strengthening. Four beams were cast and tested in torsion: i) a control beam without vertical reinforcement, ii) two beams with internal stirrups designed for shear and torsion demands using different stirrup spacing (50 and 100 mm), and iii) a beam having steel stirrups with a spacing of 100 mm strengthened using high ductile post-tensioned metal straps (PTMS). The main objective of the PTMS strengthening solution was to investigate the enhancement of torsional strength confined along the beam. The failure modes, torsional capacities, rotation, and strengthening performance in torsion are discussed in in this study. The experimental results indicate that the PTMS improved the cracking torque capacity by up to 15 % compared to the control beam. Moreover, the PTMS also increased the ultimate torque by up to 19 % compared to the unstrengthened beam. Current code equations to predict the torsional capacity of RC beams are also compared with the experimental results. It is found that the predictions obtained by current ACI equation gives a good agreement and yield in general conservative values compared to the experimental ones.

Nonlinear FEM Analysis of Experimentally Tested Flat Slabs with Openings

2019 ◽  
Vol 292 ◽  
pp. 191-196 ◽  
Author(s):  
Tomáš Augustín ◽  
Ľudovít Fillo ◽  
Jaroslav Halvonik
Keyword(s):  
Model Calibration ◽  
Fem Analysis ◽  
Linear Analysis ◽  
Experimental Results ◽  
Nonlinear Fem ◽  
Flat Slabs ◽  
The World ◽  
The Face ◽  
Effective Depth ◽  
Reference Specimens

Experimental programs focused on the issues related to the flat slabs still attract the attention of the scientists around the world. At the Central Laboratories of STU in Bratislava, together 8 fragments of the flat slabs were tested, focusing on the influence of the openings on the punching resistance. The two reference specimens were without openings and the others had two symmetrically placed openings. The openings were moved from the face of the column in multiples of the effective depth (0d, 1d, 2d). For the assessment of the tests, the models introduced in the relevant standards and codes were applied. The experimental results were also used for NFEM model calibration. The paper will deal with comparison of the theoretical and experimental results as well as with non-linear analysis that was performed in the ATENA FEM program, with the goal to obtain the most realistic behaviour of the flat slabs with openings. The material properties used in the analysis were obtained from the laboratory tests.

scholarly journals Performance of Notched Connectors for CLT-Concrete Composite Floors

Buildings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 122
Author(s):  
Minh Van Thai ◽  
Sylvain Ménard ◽  
Sidi Mohammed Elachachi ◽  
Philippe Galimard
Keyword(s):  
Element Model ◽  
Maximum Load ◽  
Edge Length ◽  
Experimental Results ◽  
Notch Depth ◽  
Long Span ◽  
Brittle Rupture ◽  
Screw Length ◽  
Floor Systems ◽  
And Behavior

CLT-concrete composite floor systems are a solution for timber buildings with a long-span floor. It yields a reduction of carbon footprint and even eco-friendly structure at the end of its service life. This study will evaluate the structural performance of notched connectors in the CLT-concrete composite floor, comprised of the serviceability stiffness, maximum load, and behavior at failure. The parameters of the test plan are the loaded edge length, the notch depth, the concrete thickness, and the screw length. Other secondary variables are also assessed, such as different loading sequences, speed of test, and timber moisture content. Experimental results prove that the performance of the connector depends significantly but not linearly on the notch depth and the length of the loaded edge. The connector with a deeper notch and a shorter heel will be stiffer and more robust, but it also tends to have a brittle rupture. The test results also help validate a solution for deconstructable connector systems. A nonlinear finite element model of the connector is built and validated versus the experimental results. It yields reasonably good predictions in terms of resistance and can capture the load-slip relationship.

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