scholarly journals Local Behavior of Lap-Spliced Deformed Rebars in Reinforced Concrete Beams

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7186
Author(s):  
Agha Syed Muhammad Gillani ◽  
Seung-Geon Lee ◽  
Soo-Hyung Lee ◽  
Hyerin Lee ◽  
Kee-Jeung Hong

Twelve full-scale reinforced concrete beams with two tension lap splices were constructed and tested under a four-point loading test. Half of these beams had shorter lap splices than that recommended by American Concrete Institute Building Code ACI 318-19; they failed by bond loss between steel and concrete at the lap splice region before rebar yielding. The other half of the beams were designed with a lap splice length slightly exceeding that recommended by ACI 318-19; they failed by rebar yielding and exhibited a ductile behavior. Several strain gauges were attached to the longitudinal bars in the lap splice region to study the local behavior of deformed bars during loading. The strain in a rebar was maximum at the loaded end of the lap splice and progressively decreased toward the unloaded end because the rebar at this end could not sustain any load. Stress flow discontinuity occurred at the loaded end and caused stress concentration. The effect of this concentration was investigated based on test results. The comparison of bond strengths calculated by existing equations and those of tested specimens indicated that the results agreed well.

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Constantin E. Chalioris ◽  
Constantin P. Papadopoulos ◽  
Constantin N. Pourzitidis ◽  
Dimitrios Fotis ◽  
Kosmas K. Sideris

This paper presents the findings of an experimental study on the application of a reinforced self-compacting concrete jacketing technique in damaged reinforced concrete beams. Test results of 12 specimens subjected to monotonic loading up to failure or under repeated loading steps prior to total failure are included. First, 6 beams were designed to be shear dominated, constructed by commonly used concrete, were initially tested, damaged, and failed in a brittle manner. Afterwards, the shear-damaged beams were retrofitted using a self-compacting concrete U-formed jacket that consisted of small diameter steel bars and U-formed stirrups in order to increase their shear resistance and potentially to alter their initially observed shear response to a more ductile one. The jacketed beams were retested under the same loading. Test results indicated that the application of reinforced self-compacting concrete jacketing in damaged reinforced concrete beams is a promising rehabilitation technique. All the jacketed beams showed enhanced overall structural response and 35% to 50% increased load bearing capacities. The ultimate shear load of the jacketed beams varied from 39.7 to 42.0 kN, whereas the capacity of the original beams was approximately 30% lower. Further, all the retrofitted specimens exhibited typical flexural response with high values of deflection ductility.


2011 ◽  
Vol 243-249 ◽  
pp. 1461-1465
Author(s):  
Chuan Min Zhang ◽  
Chao He Chen ◽  
Ye Fan Chen

The paper makes an analysis of the reinforced concrete beams with exterior FRP Shell in Finite Element, and compares it with the test results. The results show that, by means of this model, mechanical properties of reinforced concrete beams with exterior FRP shell can be predicted better. However, the larger the load, the larger deviation between calculated values and test values. Hence, if more accurate calculation is required, issues of contact interface between the reinforced concrete beams and the FRP shell should be taken into consideration.


2010 ◽  
Vol 37 (8) ◽  
pp. 1045-1056 ◽  
Author(s):  
Christopher Suffern ◽  
Ahmed El-Sayed ◽  
Khaled Soudki

This paper reports experimental data on the structural performance of disturbed regions in reinforced concrete beams with corrosion damage to the embedded steel stirrups. A total of 15 reinforced concrete beams were constructed and tested. The test beams were 350 mm deep, 125 mm wide, and 1850 mm long. The beams were tested in three-point bending under a simply supported span of 1500 mm. Nine beams had the embedded stirrups subjected to accelerated corrosion. The test variables were the corrosion damage level and the shear span-to-depth ratio. The test results indicated that the corroded beams exhibited reduced shear strength in comparison to the uncorroded control specimens. The shear strength reduction was up to 53%. Furthermore, the reduction in shear strength due to the corrosion was found to be greater at smaller shear span-to-depth ratios.


2011 ◽  
Vol 255-260 ◽  
pp. 504-508
Author(s):  
Li Song ◽  
Zhi Wu Yu

The behavior of materials under repeated loading has been examined, but extended studies are more and more needed especially for damaged reinforced structures such as bridges, where high-cycle fatigue phenomena and corrosion can be significant. In the present paper, a theoretical model based on fatigue performance of materials and stress analysis for cross-section is proposed in order to analyze the fatigue damage of corroded reinforced concrete beams under repeated loads. Further, fatigue life is predicted by applying this method, and the method is evaluated by test results.


2008 ◽  
Vol 385-387 ◽  
pp. 41-44 ◽  
Author(s):  
Shi Qi Cui ◽  
Jin Shan Wang ◽  
Zhao Zhen Pei ◽  
Zhi Liu

Reinforced concrete beams strengthened with externally bonded CFRP sheet and prestressed CFRP are analyzed in this paper. Crack developments and displacements with curvatures for different beams are analyzed. Test results show that prestressed CFRP are able to control the development of macro cracks in concrete and prestressed CFRP is an effective method to improve the toughness of concrete, reduce strengthening cost and meanwhile enhance bearing capacity of concrete beams.


2012 ◽  
Vol 517 ◽  
pp. 601-605
Author(s):  
Zhao Hua Du ◽  
Tong Hao ◽  
Li Xin Liu

This paper presents the test results of 6 reinforced concrete beams with recycled aggregates of construction waste under flexure, the beams were made of two strength grade concrete of and with different recycled aggregate replacement rate. The results indicate: the ultimate bearing capacity of recycled concrete beams with natural aggregate concrete beams are almost the same, and can meet the requirements of chinese code; The cracking resistance of the reinforced recycled concrete beams is slightly less than that of the beams with natural aggregates, the influence of recycled aggregate replacement rate to cracking resistance is not obvious. Recycled concrete beam crack load the calculated value is greater than the measured value, should carry out the theoretical value adjustment. Reinforced concrete beams is one of concrete structures, its the most common and most important component, Study of flexural property of reinforced concrete for recycled concrete structure component in the popularization and application to have the important significance [. This paper presents the test results of 6 reinforced concrete beams with recycled aggregates of construction waste under flexure, the beams were made of two strength grade concrete of C30 and C40 and with different recycled aggregate replacement rate of 0%, 50% and 70%. These results may be as a reference for the application of the concrete with recycled aggregates of construction waste in engineering [2,3,.


2016 ◽  
Vol 845 ◽  
pp. 132-139
Author(s):  
Mochamad Teguh ◽  
Novia Mahlisani

The limited lengths of reinforcing bars have been commonly found in the practical construction of most reinforced concrete structures. The required length of a bar may be longer than the available stock of steel length. For maintaining desired continuity of the reinforcement in almost all reinforced concrete structures, some reinforcing bars should be carefully spliced. In the case of long flexural beam, bar installers end up with two or even more pieces of steel that must be spliced together to accomplish the desired steel length. An experimental study was conducted to investigate flexural behavior of reinforced concrete beams utilizing a variety lap splices of reinforcing steel bars under two-point loading. Five variations of lap splices of reinforcing steel bars positioned at midspan of tensile reinforcement of the beam were investigated. Welded joints and overlapped splices were used to construct the variation of lap splices of reinforcing steel bars. The general trend in crack pattern, the load deflection characteristics and the mode of failure of flexural beams under two-point loading were also observed. The flexural strength comprising load-displacement response, flexural crack propagation, displacement ductility is briefly discussed in this paper.


2014 ◽  
Vol 936 ◽  
pp. 1438-1441
Author(s):  
Qing Yi Liu ◽  
Xiao Mei Liu

Three reinforcement materials with steel plate, epoxies resin sheet, and glass fiber sheet adhering to failed reinforced concrete beams (RC beams) were used to improve the bearing capacity of Reinforced Concrete beams in the paper. The test results shows all the three materials were proved satisfied with bearing capacity increasing request. Strengthening effects with steel plate and epoxies resin sheet were more obvious.


2001 ◽  
Vol 28 (2) ◽  
pp. 271-281 ◽  
Author(s):  
Christophe Deniaud ◽  
JJ Roger Cheng

This paper reviews the different shear design methods found in the literature for reinforced concrete beams strengthened externally with fibre reinforced polymer (FRP) sheets and compares the adequacy of each method by using the test results from the University of Alberta. The FRP shear design methods presented include the effective FRP strain and the bond mechanism criteria, the strut-and-tie model, the modified compression field theory, and a mechanical model based on the strip method with shear friction approach. Sixteen full-scale T-beam test results were used in the evaluation. Two web heights of 250 and 450 mm and two ready mix concrete batches of 29 and 44 MPa were used in the test specimens. Closed stirrups were used with three spacings: 200 mm, 400 mm, and no stirrups. Three types of FRP were used to strengthen externally the web of the T-beams: (i) uniaxial glass fibre, (ii) triaxial (0/60/–60) glass fibre, and (iii) uniaxial carbon fibre. The results showed that the mechanical model using the strip method with shear friction approach evaluates better the FRP shear contribution. The predicted capacities from this mechanical model are also found conservative and in excellent agreement with the test results.Key words: beams, carbon fibres, composite materials, fibre reinforced polymers, glass fibres, rehabilitation, reinforced concrete, shear strength, sheets, tests.


2012 ◽  
Vol 201-202 ◽  
pp. 304-307
Author(s):  
Li Yun Pan ◽  
Cheng Chen ◽  
Shun Bo Zhao ◽  
Chang Yong Li

Two large impaired reinforced concrete beams with pre-loading cracks were strengthened by the externally bonded steel frame composed with bottom steel plate and side hoop steel belts. The cyclic loading behaviors of these beams were tested to verify the effectiveness of this strengthening method specified in current Chinese design code. Based on the analyses of test results, the steel plate worked well with bonded concrete under normal service load, the hoop steel belts were necessary to prevent the peeling of bottom steel plate. The strengthened beams were effectively enhanced in flexural stiffness and ultimate resistance, and no new cracks appeared under the normal service load.


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