scholarly journals Effect of Web Openings on Flexural Behaviour of Underground Metro Station RC Beams under Static and Cyclic Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Ting-jin Liu ◽  
Si-wei Chen ◽  
Zi-hang Feng ◽  
Hong-yuan Liu
Keyword(s):  
Cyclic Loading ◽  
Rc Beams ◽  
Flexural Behaviour ◽  
Underground Engineering ◽  
Engineering Project ◽  
Metro Station ◽  
Web Openings ◽  
Web Opening ◽  
Static And Cyclic Loading ◽  
The Impact

This paper investigates the influence of multiple transverse web openings on the flexural behaviour of underground metro station reinforced concrete (RC) beams. This problem is outlined with an actual underground engineering project, in which the web opening used in the RC beams violates the current specifications. A total of five beams with different numbers of web openings are fabricated and tested under static and cyclic loading conditions, thereby simulating actual operations in unfavourable conditions. The results suggest that the existence of the openings decreases the loadbearing capacity, ductility, stiffness, and energy dissipation ability of the RC beams. Moreover, the results show that the corners of the openings are the weakest parts of the beams. However, additional reinforcements around the openings can partially mitigate the impact of the openings on the loadbearing and seismic performance of the RC beams. The laboratory experiments presented herein not only provide guidelines for the use of RC beams with web openings in actual engineering projects, especially underground projects where RC beams with web openings have seldom been investigated, but also shed light on improving the related design specifications.

Shear Capacity of RC Beams with Web Openings Strengthened with Multi Layers of CFRP

2014 ◽  
Vol 567 ◽  
pp. 494-498 ◽  
Author(s):  
Bashar S. Mohammed ◽  
Omar Alanni
Keyword(s):  
Reduction Factor ◽  
Shear Capacity ◽  
Fiber Reinforced Polymer ◽  
Rc Beam ◽  
Rc Beams ◽  
Web Openings ◽  
Web Opening ◽  
Reinforced Polymer ◽  
Eurocode 2 ◽  
Load Carrying

In some cases a cut-out web opening in a reinforced concrete (RC) beam is required to facilitate the passage of electrical and mechanical pipes and ducting from one side to another. The presence of cut-out web openings will lead to decreasing in the load carrying capacity of these RC beams. Therefore, strengthening the vicinity of these openings by using Carbon Fiber Reinforced Polymer (CFRP) will represent the best practical solution. In this study, thirteen RC beams with different sizes of cut-out web openings and with different layers of CFRP strengthening and also one solid RC beam (control) were prepared and tested to failure. The outcome of this experimental and analytical study showed that the modified Eurocode 2 model can reasonably be used in computing the shear forces of RC beams having the vicinity of their cut-out web openings strengthened with single/multi layers of CFRP. In addition, for safe design purposes, a reduction factor has been suggested as well.

Mitigating the impact of the static and cyclic loading on loose coastal saturated sands utilizing a waterproof and super-fast curing polymer

2021 ◽  
Vol 148 ◽  
pp. 106838
Author(s):  
Milad Banitalebi Dehkordi ◽  
Mohammadali Rowshanzamir ◽  
Sayyed Mahdi Hejazi ◽  
Naeim Pishehvarzad ◽  
Hamid Hashemolhosseini
Keyword(s):  
Cyclic Loading ◽  
Saturated Sands ◽  
Static And Cyclic Loading ◽  
The Impact

Flexural Performance of Strengthened RC Beams with CFRP Laminates Subjected to Cyclic Loading

2011 ◽  
Vol 471-472 ◽  
pp. 697-702 ◽  
Author(s):  
R. Hawileh ◽  
J.A. Abdalla ◽  
Adil K. Al-Tamimi
Keyword(s):  
Cyclic Loading ◽  
Failure Modes ◽  
Experimental Testing ◽  
Seismic Retrofitting ◽  
Bench Mark ◽  
Rc Beams ◽  
Cfrp Laminates ◽  
Cfrp Plate ◽  
External Strengthening ◽  
Static And Cyclic Loading

Seismic retrofitting of reinforced concrete (RC) beams by means of carbon fiber reinforced polymer (CFRP) composites is one of the state-of-the-art techniques that have been widely practiced lately. Such external strengthening schemes seem to enhance both stiffness and strength of RC beams when subjected to static and cyclic loading. Extensive research investigation has been carried out for beams subjected to monotonic static loading while limited research data is available for beams subjected to cyclic loadings. Therefore, this study is initiated and its aim is to present the results of full scale experimental testing of RC beams under four-point-bending loading and subjected to monotonic and cyclic loading histories up to failure of the specimens. An unstrengthened RC beam was tested monotonically to serve as a bench-mark. The remaining two externally strengthened RC beams with different anchorage schemes were tested under cyclic loading. The strengthening test matrix included beams bonded with a unidirectional CFRP plate that covers 90% of the beam's soffit length, with one or two unidirectional layers of CFRP wraps at anchorage locations along the beam's length. The anchorage locations were at the edges of the CFRP plate and at the middle of the beam's span. The results presented herein show an increase in the overall strength for the strengthened beams over the unstrengthened ones. The different failure modes and the resulting ductility of the tested specimens are also discussed. This study is considered to be the first part of an extensive program that aims to investigate the different parameters that govern the external strengthening techniques of RC beams when subjected to cyclic loading.

A review on the behaviour of reinforced concrete beams with fibre-reinforced polymer-strengthened web openings

2021 ◽  
pp. 136943322110463
Author(s):  
Xuefei Nie ◽  
Shishun Zhang ◽  
Zeyu Gao ◽  
Zhuo Zeng
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Web Openings ◽  
Web Opening ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Frp Strengthening ◽  
The Web

Web openings often need to be created in reinforced concrete (RC) beams for the passages of utility ducts and/or pipes. Such web openings reduce the cross-section area of the beam in the affected region, leading to decrease in its load-carrying capacity and stiffness. Therefore, a fibre-reinforced polymer (FRP)-strengthening system generally needs to be applied around the web opening to ensure the safety of the weakened beam. A number of studies have been conducted by researchers all over the world to examine the behaviour of RC beams with FRP-strengthened web opening/web openings, and plenty of useful findings have been generated. This article presents a critical literature review of existing relevant research from three aspects: experimental studies, numerical studies and theoretical studies. The effect of main factors, including the size, shape, location and number of the web opening, the shape and shear span ratio of the beam, the concrete strength, the loading scheme and the FRP-strengthening scheme, on the structural performance of RC beams with FRP-strengthened web opening/web openings have been thoroughly analysed and discussed. Finally, directions for future research based on the gaps which exist in existing studies are pointed out.

scholarly journals Fatigue Stress-Life Model of RC Beams Based on an Accelerated Fatigue Method

2019 ◽  
Vol 4 (2) ◽  
pp. 16
Author(s):  
Eljufout ◽  
Toutanji ◽  
Al-Qaralleh
Keyword(s):  
Cyclic Loading ◽  
Fatigue Testing ◽  
Three Dimensional ◽  
Rc Beam ◽  
Rc Beams ◽  
Testing Methods ◽  
Load Range ◽  
Fatigue Stress ◽  
Life Model ◽  
Prediction Band

Several standard fatigue testing methods are used to determine the fatigue stress-life prediction model (S-N curve) and the endurance limit of Reinforced Concrete (RC) beams, including the application of constant cyclic tension-tension loads at different stress or strain ranges. The standard fatigue testing methods are time-consuming and expensive to perform, as a large number of specimens is needed to obtain valid results. The purpose of this paper is to examine a fatigue stress-life predication model of RC beams that are developed with an accelerated fatigue approach. This approach is based on the hypothesis of linear accumulative damage of the Palmgren–Miner rule, whereby the applied cyclic load range is linearly increased with respect to the number of cycles until the specimen fails. A three-dimensional RC beam was modeled and validated using ANSYS software. Numerical simulations were performed for the RC beam under linearly increased cyclic loading with different initial loading conditions. A fatigue stress-life model was developed that was based on the analyzed data of three specimens. The accelerated fatigue approach has a higher rate of damage accumulations than the standard testing approach. All of the analyzed specimens failed due to an unstable cracking of concrete. The developed fatigue stress-life model fits the upper 95% prediction band of RC beams that were tested under constant amplitude cyclic loading.

Behaviour of RC beam repaired using alkali activated slag-based agent under static and cyclic loading

Structures ◽  
2021 ◽  
Vol 31 ◽  
pp. 761-768
Author(s):  
Sulaem Musaddiq Laskar ◽  
Ruhul Amin Mozumder ◽  
Aminul Islam Laskar
Keyword(s):  
Cyclic Loading ◽  
Rc Beam ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Static And Cyclic Loading ◽  
Alkali Activated
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