Monotonic and fatigue assessment of steel-concrete composite beams strengthened with externally post-tensioned tendons

2018 ◽  
Author(s):  
◽  
Ayman Elzohairy
Keyword(s):  
Numerical Model ◽  
Composite Beam ◽  
Composite Beams ◽  
Fatigue Tests ◽  
Flexural Behavior ◽  
Bending Test ◽  
Steel Beam ◽  
Premature Failure ◽  
Post Tensioning ◽  
Post Tensioned

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The steel-concrete composite beam represents a structural system widely employed in both buildings and girder bridges. The coupling between steel beams and concrete flanges assures both economic and structural benefits because of quick construction of steel structures and large increase in stiffness due to the presence of concrete. Strengthening with external post-tensioning (PT) force is particularly effective and economical for long-span steel-concrete composite beams and has been employed with great success to increase the bending and shear resistance and correct excessive deflections. Applying external PT force to the steel-concrete composite beam is considered an active strengthening technique that can create permanent internal straining action in the beam which is opposite to the existing straining action due to the applied service loads. The most benefits of using this system of strengthening are an elastic performance to higher loads, higher ultimate capacity, and reduction in deformation under the applied loads. Under service loads, bridge superstructures are subjected to cyclic loads which may cause a premature failure due to fatigue. Therefore, fatigue testing is critical to evaluate existing design methods of steel-concrete composite beams. ... This research presents static and fatigue tests on four steel-concrete composite specimens to evaluate the effect of externally post-tensioned tendons on the ultimate strength and fatigue behavior of composite beams. Fatigue tests are conducted to a million cycles under a four-point bending test. In addition, final static tests are performed on fatigued specimens to evaluate the residual strength of the strengthened specimen. A numerical model is described to predict the fatigue response of the composite beam by considering the fatigue damage in the concrete flange. The accuracy of the developed numerical model is validated using the existing test data. The static test results indicate that the external post-tensioning force improves the flexural behavior of the strengthened specimen by increasing the beam capacity and reducing the tensile stress in the bottom flange of the steel beam. The fatigue results demonstrate that the external post-tensioning significantly decreases the strains in the shear connectors, concrete flange, and steel beam. The tendons demonstrated an excellent fatigue performance, with no indication of distress at the anchors.

Parametric study for post-tensioned composite beams with external tendons

2017 ◽  
Vol 20 (10) ◽  
pp. 1433-1450 ◽  
Author(s):  
Ayman El-Zohairy ◽  
Hani Salim
Keyword(s):  
Numerical Model ◽  
Test Data ◽  
Fatigue Cracks ◽  
Composite Beams ◽  
Flexural Behavior ◽  
Nonlinear Simulation ◽  
Shear Connection ◽  
Strengthened Beam ◽  
Post Tensioning ◽  
Post Tensioned

Strengthening of bridge superstructures composite beams with external post-tensioned tendons is a good technique for strengthening the existing structures. In this study, a numerical model is illustrated to study the nonlinear simulation of composite beams stiffened with externally post-tensioned tendons. The accuracy of the developed numerical model is validated using comparisons between the numerical and existing test data. The influence of various strengthening parameters is investigated, which include draped versus straight tendons, tendon length, the effect of post-tensioning on reinstating the flexural behavior of an overloaded beam, tendon eccentricity, and the degree of shear connection. A good agreement between the proposed model and the test data is obtained. The results demonstrate that at the same tendon eccentricity, the trapezoidal profile shows better behavior for the strengthened beams. However, more ductility is obtained when using the straight tendon profile. Applying post-tensioning through the beam of full length helps to reduce the creation of fatigue cracks, which always start at stress raisers, and subsequently increases the fatigue life of the composite beam. Also, the external post-tensioning effectively maintains the flexural behavior of the overloaded strengthened beam after unloading in comparison to the un-strengthened beam. It is observed that 80% degree of shear connection or higher is recommended to obtain the desired performance of the external post-tensioning force for strengthening composite beams.

Flexural behavior of functionally graded polymeric composite beams

2021 ◽  
pp. 152808372110003
Author(s):  
M Atta ◽  
A Abu-Sinna ◽  
S Mousa ◽  
HEM Sallam ◽  
AA Abd-Elhady
Keyword(s):  
Flexural Strength ◽  
Volume Fraction ◽  
Stress Gradient ◽  
Polymeric Composite ◽  
Composite Beams ◽  
Functionally Graded ◽  
Flexural Behavior ◽  
Bending Test ◽  
Polymeric Composite Material ◽  
Fiber Volume

The bending test is one of the most important tests that demonstrates the advantages of functional gradient (FGM) materials, thanks to the stress gradient across the specimen depth. In this research, the flexural response of functionally graded polymeric composite material (FGM) is investigated both experimentally and numerically. Fabricated by a hand lay-up manufacturing technique, the unidirectional glass fiber reinforced epoxy composite composed of ten layers is used in the present investigation. A 3-D finite element simulation is used to predict the flexural strength based on Hashin’s failure criterion. To produce ten layers of FGM beams with different patterns, the fiber volume fraction ( Vf%) ranges from 10% to 50%. A comparison between FGM beams and conventional composite beams having the same average Vf% is made. The experimental results show that the failure of the FGM beams under three points bending loading (3PB) test is initiated from the tensioned layers, and spread to the upper layer. The spreading is followed by delamination accompanied by shear failures. Finally, the FGM beams fail due to crushing in the compression zone. Furthermore, the delamination failure between the layers has a major effect on the rapidity of the final failure of the FGM beams. The present numerical results show that the gradient pattern of FGM beams is a critical parameter for improving their flexural behavior. Otherwise, Vf% of the outer layers of the FGM beams, i.e. Vf% = 30, 40, or 50%, is responsible for improving their flexural strength.

FINITE ELEMENT MODELING TO PREDICT FLEXURAL PERFORMANCE OF STEEL I-SECTION BEAM EXTERNALLY BONDED BY VARIOUS FRP FABRICS: A REVIEW .

2021 ◽  
Vol 10 (5) ◽  
pp. 83-88
Keyword(s):  
Fatigue Behavior ◽  
Steel Structure ◽  
Adhesive Bond ◽  
Cost Comparison ◽  
Flexural Behavior ◽  
Bending Test ◽  
Fiber Reinforced Polymers ◽  
Steel Beam ◽  
Bottom Flange ◽  
Frp Sheet

Use the fiber reinforced polymers fabric (FRP) in repair and strengthening of bridges, steel structure, etc. This article is review of literature available on flexural behavior of I-section steel beams with externally attached with FRP fabrics. It can be useful to decide which FRP sheet is best to use with steel beam to enhance flexural strength. Also this study comprises of cost comparison of Steel I beam strengthened by various FRP i.e. Basalt-FRP, Glass-FRP and Carbon-FRP. This can be achieved by bonding various FRP sheet at bottom flange, top flange & two faces of web to steel I section beam. It was studied through experimental, analytical, numerical investigation. Most of work is done on carbon-FRP fabric attached to steel beam as compared with Basalt-FRP. Some literature studied properties of FRP, adhesive bond, and fatigue behavior. In experimental method, four point bending test was performed and model were analyzed using FE analysis. From this review, Carbon-FRP gives better performance of Steel I beam as compared with other FRPs.

scholarly journals Flexural Behavior of Fiber-Reinforced Self-Stressing Concrete T-Shaped Composite Beams

2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Boxin Wang ◽  
Ruichang Fang ◽  
Qing Wang
Keyword(s):  
Composite Beam ◽  
Mechanical Analysis ◽  
Composite Beams ◽  
Experimental Results ◽  
Flexural Behavior ◽  
Fiber Reinforced ◽  
Beam Test ◽  
Test Beam ◽  
Bending Performance ◽  
Laminated Layer

Given the excellent crack resistance performance of steel fiber-reinforced self-stressing concrete (SFRSSC), the bending performance of some composite beams with SFRSSC laminated layers was studied. The experiment conducted in this study comprised a single-span composite beam test (including 3 test beams) and a two-span continuous composite beam test (including 2 test beams). All the test beams were T-shaped. The cracking load, yielding load, and ultimate load of all the test beams were recorded and comparatively analyzed. Experimental results showed that the cracking load of the test beam with an SFRSSC laminated layer is significantly increased. Mechanical analysis and numerical simulation of the test beams were conducted, and the obtained results agreed well with the experimental results. The composite beams under different working conditions were also numerically simulated. Through the simulation, reasonable ranges of precompressive stress and length of the SFRSSC laminated layer at intermediate support of continuous composite beam were obtained.

Research on Key Issues in Design of Outer-Plated Steel-Concrete Continuous Composite Beams

2012 ◽  
Vol 166-169 ◽  
pp. 414-419
Author(s):  
Li Hua Chen ◽  
Fei Xiao ◽  
Qi Liang Jin
Keyword(s):  
Composite Beam ◽  
Bending Moment ◽  
Longitudinal Shear ◽  
Structural Features ◽  
Composite Beams ◽  
Steel Beam ◽  
Negative Moment ◽  
Key Issues ◽  
Negative Bending ◽  
The Moment

Based on the theoretical analysis and testing results, some key issues in design of outer-plated steel-concrete continuous composite beams are discussed. The influence of the form of steel beam upper flange on the behavior of composite beam is analyzed. The requirements about longitudinal reinforcement strength in the concrete flange of the negative moment region are given. It is suggested that the moment-shear interaction should be neglected when calculating the flexural capacity of outer-plated steel-concrete composite beams under negative bending moment. The behavior of longitudinal shear resistance at the interface between the concrete flange and web of composite beam is studied, and the related calculating formula is put forward based on the structural features of the composite beam.

scholarly journals Numerical Modelling Of The Strengthening Process Of Steel-Concrete Composite Beams

2015 ◽  
Vol 19 (4) ◽  
pp. 99-110 ◽  
Author(s):  
Piotr Szewczyk ◽  
Maciej Szumigała
Keyword(s):  
Numerical Modelling ◽  
Bearing Capacity ◽  
Composite Beam ◽  
Steel Plate ◽  
Composite Beams ◽  
Steel Beam ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Main Assumption ◽  
The Cost

Abstract This paper presents the numerical modelling of strengthening a steel-concrete composite beam. The main assumption is that the strengthening is not the effect of the state of a failure of a structure, but it resulted from the need to increase the load-bearing capacity and stiffness of the structure (for example: due to a change in the use of the object). The expected solution is strengthening without the necessity to completely unload the structures (to reduce the scope of works, the cost of modernization and to shorten the time). The problem is presented on the example of a composite beam which was strengthened through welding a steel plate to the lower flange of the steel beam. The paper describes how energy parameters are used to evaluate the efficiency of structures’ strengthening and proposes an appropriate solution.

scholarly journals FLEXURAL TESTING OF WOOD-CONCRETE COMPOSITE BEAM MADE FROM KAMPER AND BANGKIRAI WOOD

2015 ◽  
Vol 2 (2) ◽  
Author(s):  
Fengky Satria Yoresta
Keyword(s):  
Composite Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Bending Test ◽  
Cinnamomum Camphora ◽  
Shear Cracks ◽  
Coarse Aggregates ◽  
Flexural Testing ◽  
Fine Aggregates

Certain wood has a tensile strength that almost equal with steel rebar in reinforced concrete beams. This research aims to understand the capacity and flexural behavior of concrete beams reinforced by wood (wood-concrete composite beam). Two different types of beams based on placement positions of wood layers are proposed in this study. Two kinds of wood used are consisted of Bangkirai (Shorea laevifolia) and Kamper (Cinnamomum camphora), meanwhile the concrete mix ratio for all beams is 1 cement : 2 fine aggregates : 3 coarse aggregates. Bending test is conducted by using one-point loading method. The results show that composite beam using Bangkirai wood is stronger than beams using Kamper wood. More thicker wood layer in tensile area will increase the flexural strength of beams. Crack patterns identified could be classified into flexural cracks, shear cracks, and split on wood layer Beberapa jenis kayu tertentu memiliki kekuatan tarik yang hampir sama dengan tulangan baja pada balok beton bertulang. Penelitian ini bertujuan memahami kapasitas dan perilaku lentur balok beton bertulang yang diperkuat menggunakan kayu (balok komposit beton-kayu). Dua tipe balok yang berbeda berdasarkan posisi penempatan kayu digunakan dalam penelitian ini. Dua jenis kayu yang digunakan adalah kayu Bangkirai (Shorea laevifolia) and Kamper (Cinnamomum camphora), sementara itu rasio campuran beton untuk semua balok menggunakan perbandingan 1 semen : 2 agregat halus : 3 agregat kasar. Pengujian lentur dilakukan menggunakan metode one-point loading. Hasil penelitian menunjukkan bahwa balok komposit dengan kayu Bangkirai lebih kuat dibandingkan balok dengan kayu Kamper. Semakin tebal lapisan kayu yang berada di daerah tarik akan meningkatkan kekuatan lentur balok. Pola kerusakan yang teridentifikasi dapat diklasifikasikan menjadi retak lentur, retak geser, dan pecah pada kayu

scholarly journals An Investigation of Crack Propagation in Steel Fiber-Reinforced Composite Beams

2018 ◽  
Author(s):  
Adam Soto ◽  
Fariborz M. Tehrani
Keyword(s):  
Composite Beam ◽  
Peak Load ◽  
Experimental Studies ◽  
Fiber Reinforcement ◽  
Composite Beams ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Premature Failure ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite

This paper investigates the cracking phenomena of fiber-reinforced concrete in steel and concrete composite beam systems. Various parameters contribute to the crack development and weakening of the composite system, while the concrete slab is bonded to the steel beam. The weakening can result from the longitudinal shear stress that causes cracking from shear connectors, cracking from tensile forces, crushing due to compressive forces and also cracking from concrete shrinkage. These cracks can contribute to premature failure of the composite beam. This paper investigates fiber reinforcement as a solution to decrease the amount of cracking in composite beams. The presented methodology includes experimental studies to evaluate cracking characteristics and strength of fiber-reinforced composite beams. Parameters of the study included spacing between studs, application of welded wire reinforcement, and fiber reinforcement. Results indicate the effectiveness of fiber-reinforcement in reducing crack widths and number of cracks, even though, spacing between studs and presence of welded wire were essential in crack control. Further, fiber-reinforced specimens showed higher compressive and tensile strength by 30% and 70% respectively. The deflection at the peak load also showed a 23% decrease for the specimen with hybrid fiber-wire reinforcement in comparison with the specimen reinforced with welded wire only.

scholarly journals Flexural Design and Analysis of Composite Beams with Inverted-T Steel Girder with Ultrahigh Performance Concrete Slab

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Wonchang Choi ◽  
Youngcheol Choi ◽  
Sung-Won Yoo
Keyword(s):  
Composite Beam ◽  
Steel Fiber ◽  
Concrete Slab ◽  
Composite Beams ◽  
Flexural Behavior ◽  
Slab Thickness ◽  
Horizontal Shear ◽  
Steel Girder ◽  
Beam Combining ◽  
Ductile Behavior

This study intends to improve the efficiency of the composite beam combining a slab made of steel fiber-reinforced ultrahigh performance concrete (UHPC) and a steel girder without top flange. To that goal, the experiment is conducted on 24 composite beams fabricated with varying compressive strength of UHPC, steel fiber content, stud spacing, and slab thickness to evaluate the behavior of the studs and the flexural behavior of the composite beam combining the UHPC slab and the inverted-T steel girder. The experimental results show the test members developed sufficient ductile behavior with respect to the slip limit of 6 mm stipulated in Eurocode-4 and regardless of the considered test variables. The experimental ultimate horizontal shear force is seen to be clearly larger than the static strengths of the stud predicted by Eurocode-4 and AASHTO-LRFD. Improved design formulae for the composite beam shall be derived to reflect the UHPC slab thickness.

scholarly journals Numerical analysis of the effect of partial interaction in the evaluation of the effective width of composite beams

2018 ◽  
Vol 11 (4) ◽  
pp. 757-778
Author(s):  
A. R. SILVA ◽  
L. E. S. DIAS
Keyword(s):  
Composite Beam ◽  
Concrete Slab ◽  
Composite Beams ◽  
Interface Element ◽  
Steel Beam ◽  
Real Problem ◽  
Effective Width ◽  
Plate Element ◽  
Technical Standards ◽  
Partial Interaction

Abstract Most of the engineering problems involving structural elements of steel-concrete composite beam type are approximations of the structural problem involving concrete plates connected by connectors to steel beams. Technical standards allow the replacement of the concrete plate element by a beam element by adopting a reduction in the width of the plate element known as effective width. The effective width is obtained, in most technical norms, taking into account only the parameters of beam span length and distance between adjacent beams. Numerical and experimental works found in the literature show that this effective width depends on several other parameters, such as the width and thickness of the concrete slab, and the type of loading. The objective of this work is to verify the influence of the partial interaction in the evaluation of the effective width of composite beams formed by a concrete slab connected to a steel beam with deformable connection, being used in numerical simulation three types of finite elements: a plate element for nonlinear analysis of the concrete slab; a bar element for non-linear analysis of beams with cross-section defined by a polygon; and an interface element which connects the plate and beam elements, simulating the deformation effect of the shear connectors. In the studied examples, it was found that the reduction of the shear connection stiffness at the interface between the concrete slab and the steel beam leads to a decrease in the shear lag effect and, consequently, makes the effective width of the concrete slab closer to the its real width. In another example, curves are constructed to define the effective width of a composite beam with medium stiffness. Considering maximum stresses and maximum displacements, these curves are obtained by forcing the equivalence of the approximate model with the model closest to the real problem.

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