scholarly journals Flexural Behavior of Normal and Lightweight Concrete Composite Beams

2021 ◽  
Vol 7 (3) ◽  
pp. 549-559
Author(s):  
Syahrul Syahrul ◽  
M. W. Tjaronge ◽  
Rudy Djamaluddin ◽  
A. A. Amiruddin
Keyword(s):  
Composite Beam ◽  
Lightweight Concrete ◽  
Concrete Beams ◽  
Composite Beams ◽  
Flexural Behavior ◽  
Flexural Capacity ◽  
Normal Concrete ◽  
Moment Capacity ◽  
Steel Bar ◽  
Foamed Concrete

This paper presents an experimental study of the behavior of Normal Concrete Beams (NCB) and composite beams with lightweight foamed concrete (CB), reinforced with steel bar measuring 2 f 8 mm in the compressive section and 2 D 16 mm in the tensile section, shear steel bar f 8 mm. The sample consisted of two normal concrete beams (NCB) and two composite beams with lightweight foamed concrete (CB). The main variables in this study are the type of concrete, the type of steel bar and the flexural behavior. The beam samples were tested by two-point loading, failure mode and crack width were observed. The results showed that the flexural process of normal concrete blocks (NCB) and composite beams with lightweight foamed concrete (CB) was almost the same. There is no slip failure at the combined interface, the flexural capacity of the composite beam with lightweight foamed concrete can be calculated based on the statics analysis and plane-section assumptions. To calculate the ultimate capacity of a composite beam with lightweight foamed concrete is to convert a section consisting of more than one fc' to an equivalent section consisting of one fc'. Furthermore, it is validated by calculating the theoretical moment capacity and comparing the theoretical moment capacity of the experimental results. The results of the flexural test, composite beam with lightweight foamed concrete (CB) showed ductile deflection behavior, diagonal crack patterns, and low flexural capacity of the beam (NCB). Doi: 10.28991/cej-2021-03091673 Full Text: PDF

scholarly journals Flexural Behavior of Damaged Lightweight Reinforced Concrete Beams Strengthened by CFRP

2021 ◽  
Vol 9 (ICRIE) ◽  
Author(s):  
Ali I. Salahaldin ◽  
◽  
Muyasser M. Jomaa’h ◽  
Dlovan M. Naser ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beam ◽  
Lightweight Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Load Carrying Capacity ◽  
Normal Concrete ◽  
Load Carrying

One of the most common methods of strengthening, rehabilitation, or repairing of structural lightweight concrete (LWC) elements is the external carbon fiber reinforced polymer (CFRP) strips. This paper presents an experimental study on the flexural behavior of reinforced concrete beams which comprise lightweight aggregate concrete, in different proportions, strengthened by CFRP sheets. The experimental program included six specimens with a 1500mm effective span. Two of the specimens were normal concrete beams. Another two samples were lightweight beams with a 50% aggregate replacement with pumice. The last two specimens were lightweight concrete beams with a 75% aggregate replacement with pumice. These beams were casted and tested twice under a two-point load application, once before strengthening and the other after that. The experimental results show that full strengthening of the beams along with their entire length, increase in load-carrying capacity by 75%, 113%, and 107% for normal concrete beam, (50% aggregate replacement) LWC beam, and (75% aggregate replacement) LWC beam respectively. While the middle-third strengthening of the beams shows an increase in load-carrying capacity by 64%, 72%, and 57% for normal concrete beam, (50% aggregate replacement) LWC aggregate beam, and (75% aggregate replacement) LWC beam respectively. The strength of the two types of LWC beams was almost the same and it is about 85% of the concrete beam with normal weight.

scholarly journals Experimental Study on Timber−Lightweight Concrete Composite Beams with Ductile Bolt Connectors

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2632
Author(s):  
Yafeng Hu ◽  
Yang Wei ◽  
Si Chen ◽  
Yadong Yan ◽  
Weiyao Zhang
Keyword(s):  
Composite Beam ◽  
Lightweight Concrete ◽  
Experimental Testing ◽  
Composite Beams ◽  
Strengthening Effect ◽  
Bending Performance ◽  
Maximum Deformation ◽  
Bending Failure ◽  
Push Out ◽  
Timber Beams

A timber–lightweight−concrete (TLC) composite beam connected with a ductile connector in which the ductile connector is made of a stainless−steel bolt anchored with nuts at both ends was proposed. The push−out results and bending performance of the TLC composite specimens were investigated by experimental testing. The push−out results of the shear specimens show that shear–slip curves exhibit good ductility and that their failure can be attributed to bolt buckling accompanied by lightweight concrete cracking. Through the bending tests of ten TLC composite beams and two contrast (pure timber) beams, the effects of different bolt diameters on the strengthening effect of the TLC composite beams were studied. The results show that the TLC composite beams and contrast timber beams break on the timber fiber at the lowest edge of the TLC composite beam, and the failure mode is attributed to bending failure, whereas the bolt connectors and lightweight concrete have no obvious breakage; moreover, the ductile bolt connectors show a good connection performance until the TLC composite beams fail. The ultimate bearing capacities of the TLC composite beams increase 2.03–3.5 times compared to those of the contrast beams, while the mid-span maximum deformation decrease nearly doubled.

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.

scholarly journals Flexural Behavior of Rubberized Reinforced Concrete Beams

2018 ◽  
Vol 7 (4.20) ◽  
pp. 316 ◽  
Author(s):  
Adel A. Al-Azzawi ◽  
Dalia Shakir ◽  
Noora Saad
Keyword(s):  
Ultimate Load ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Fiber Content ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Rubberized Concrete ◽  
Normal Concrete ◽  
Rubber Material ◽  
Rubber Waste

In Iraq, the use of rubber waste material in concrete is an interesting topic due to its availability in large volumes. Researches of applications of rubber waste in concrete have been increased since 2003. Many studies carried out to investigate the performance of concrete using different ratios of rubber as a replacement to fine or coarse aggregate. In this research, rubber wastes from scrapped tires have been added as fiber to concrete mix with presence of 0.5% superplasticizer. The flexural behavior of concrete beams, mechanical properties of concrete and workability of concrete mixes have been studied. Rubber fibers ranging from (2-4) mm were added in percentages of 0.5% and 1%) of the cement weight. The results have demonstrated that the addition of rubber material as fibers in natural aggregate concrete enhances its ductility, compressive strength and tensile strength compared to the normal concrete. The effect of rubber fiber content is found to be significant on the behavior of tested beams. If the fiber content increased from 0 to 0.5% the cracking load increased by 60 % and ultimate load increased by 21%. For rubberized concrete, if the fiber content increased from 0.5 to 1.0%, the cracking load decreased 7% and ultimate load increased by 4%.   

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.

Experimental study on the flexural behavior of steel tube slab composite beams and key parameters optimization

2019 ◽  
Vol 22 (11) ◽  
pp. 2476-2489 ◽  
Author(s):  
Pengjiao Jia ◽  
Wen Zhao ◽  
Yongping Guan ◽  
Jiachao Dong ◽  
Qinghe Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Composite Beams ◽  
Steel Tube ◽  
Design Guidelines ◽  
Reinforcement Ratio ◽  
Flexural Behavior ◽  
Flexural Capacity ◽  
Design Elements ◽  
Steel Bolts

This work presents an experimental study on the flexural behavior of steel tube slab composite beams subjected to pure bending. The main design elements considered in the work are the flange thickness, reinforcement ratio of high strength bolts, spacing between the tubes, and transverse patterns of the tube connections. Based on nine flexural experiments on simply supported steel tube slab specimens, the failure process and crack development in steel tube slab specimens, and their load–deflection curves are investigated. The results of the laboratory tests show that the welding of the bottom flange significantly improves the flexural capacity of the steel tube slab structure. In addition, a lower concrete’s compressive strength improves the ductility of the steel tube slab specimens. Moreover, the flexural capacities predicted from the design guidelines are in good agreement with the experimental test results. Finally, based on the numerical simulations using the ABAQUS software, a numerical model is established to further investigate the effect of the additional parameters on the flexural capacity of steel tube slab structures. The numerical results suggested that the diameter of the steel bolts and the reinforcement ratio have a limited effect on the flexural bearing capacity of the steel tube slab beams, and the ultimate bearing capacity increases linearly along with increase in the diameter of the steel bolts and the reinforcement ratio in a certain range.

scholarly journals Research on the Efficiency of Composite Beam Application in Multi-Storey Buildings

2020 ◽  
Vol 12 (20) ◽  
pp. 8328 ◽  
Author(s):  
Tomas Kinderis ◽  
Mindaugas Daukšys ◽  
Jūratė Mockienė
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Composite Beam ◽  
Concrete Beams ◽  
Residential Building ◽  
Reinforced Concrete Beam ◽  
Composite Beams ◽  
Reinforced Concrete Beams ◽  
Assessment Criteria ◽  
Floor Structure

Over the past decade, several types of composite slim floor constructions have been used in multi-storey buildings in Lithuania. In order to study the efficiency of composite beam application in steel-framed multi-storey buildings, Thorbeam (A1), Deltabeam (A2), slim floor beam (A3) and asymmetric slim floor beam (A4) were chosen and evaluated according to nine assessment criteria (beam cost (K1), initial preparation on site (K2), installation time (K3), complexity of installation technology (K4), labour costs (K5), fire resistance (K6), load bearing capacity (K7), beam versatility (K8), and availability of beams (K9)). First, the significance of the rating criteria was selected and the order of the ranking criteria was obtained (K1˃K7˃K3˃K6˃K4˃K5˃K2˃K8˃K9) by means of a survey questionnaire. Second, the beams were ranked according to the points given by the questionnaire respondents as follows: 160 points were given to A2, 144 points to A1, 129 points to A4, and 111 points to A3. Deltabeam is considered to be the most rational alternative of the four beams compared. Calculations done using the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) analysis method revealed that composite beam A2 was the best slim floor structure alternative for an eight-storey high-rise commercial residential building frame, A1 ranked second, A4 ranked third, and A3 ranked fourth. In addition, the four composite beams were compared to a reinforced concrete beam (A5) according to three assessment criteria (beam cost including installation (C1), beam self-weight (C2) and fire resistance (C3)). Deltabeam was found to be efficient for use as a slim floor structure in a multi-story building due to having the lowest cost, including installation, and self-weight, and the highest fire resistance compared to other composite beams studied. Although Deltabeams are 1.4 times more expensive than reinforced concrete beams, including installation costs, they save about 2.5% of the building’s height compared to reinforced concrete beams.

Experimental study on the flexural behavior of flat steel-concrete composite beam

2020 ◽  
Author(s):  
Xianlei Cao ◽  
Chao Cheng ◽  
Min Wang ◽  
Wen Zhong ◽  
Zhengyi Kong ◽  
...  
Keyword(s):  
Composite Beam ◽  
Design Theory ◽  
Shear Fracture ◽  
Rapid Development ◽  
Flexural Behavior ◽  
Flexural Stiffness ◽  
Moment Capacity ◽  
New Type ◽  
Flat Steel ◽  
Ductility Capacity

In this study, a new type of composite beam named flat steel-concrete composite beam is suggested for the rapid development of assembly structure. The experiment of seven flat steel-concrete composite beams and one traditional steel-concrete composite beam are performed to investigate their flexural behaviors. The failure mode of bending-shear fracture for the flat steel-concrete composite beam is found while the traditional steel-concrete composite beam fails by compression-bending fracture. The plane cross-section assumption is applicable to the flat steel-concrete composite beam. Compared with the traditional steel-concrete composite beam, the flat steel-concrete composite beam exhibits higher flexural stiffness, higher moment capacity, and higher ductility capacity. Based on the design theory of the traditional steel-concrete composite beam, simplified models for estimating the flexural stiffness and ultimate moment capacity of the flat steel-concrete composite beam are proposed, and they agree well with test data.

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

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