Reliability of Load-Carrying Capacity of RC Deep Beams

2005 ◽  
Vol 17 (6) ◽  
pp. 955-962
Author(s):  
Ju-Hyun Cheon ◽  
Tae-Hoon Kim ◽  
Sang-Cheol Lee ◽  
Hyun-Mock Shin
2019 ◽  
Vol 12 (3) ◽  
Author(s):  
Ahmed Sagban Saadoon

This study  was carried out in order to explore the behaviour of RC deep beams strengthening with CFRP strips. Eight simply supported deep beams were fabricated and tested under four-points loading scenario. Three different orientations for CFRP strips were used for strengthening the RC deep beams ; vertical, horizontal and inclined. All of the tested  samples were of the same dimensions, concrete strength and steel reinforcement. A percentage increase in load carrying capacity of 48, 19 and 38% (with respect to the unstrengthened beam) was gained for beams strengthened with vertical, horizontal and inclined FRP strips, respectively. It was concluded that the strengthening with FRP strips of vertical fabric orientation is more efficient than strengthening with horizontal or inclined orientation since the vertical orientation gives the highest load carrying capacity, largest deflections at ultimate load and smallest crack width. On the other hand, applied the FRP strips in  a horizontal orientation   was  insufficient for the strengthening purposes.


2019 ◽  
Vol 9 (17) ◽  
pp. 3637
Author(s):  
Haitao Chen ◽  
Lai Wang ◽  
Jitao Zhong

The optimal strut-and-tie models (STMs) of two typical irregular concrete deep beams were constructed using evolutionary structural optimization and compared with those of previous studies. The reinforced concrete deep beam specimens were cast according to the reinforcement designs guided by different STMs. Eight irregular concrete deep beam specimens were experimentally investigated under stepped loading, and the differences in the amount of steel used, the load-carrying capacity, and the failure pattern of the different specimens were analyzed. The results show that the optimal STMs proposed in this study have significant advantages in terms of cost-effectiveness and can simultaneously ensure the load-carrying capacity, delay the crack propagation of irregular concrete deep beams, and reduce the amount of steel used in structural members. Therefore, they have an important engineering application value for the reinforcement design of irregular concrete deep beams.


Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 101 ◽  
Author(s):  
Piotr Smarzewski

The article presents the results of experimental- and analytical investigations of the behaviour and the load-carrying capacity of deep beams with openings (DBO) and without openings (DB) made of hybrid steel-polypropylene fibre-reinforced high-performance concrete (HFRHPC) subjected to three-point bending tests. Six deep beams 100 mm × 500 mm × 1000 mm were tested with a gradually increasing load until failure. All the specimens were tested in the same simply supported conditions. The research focused on the quantity and kind of concrete reinforcement. The deep beams with steel and polypropylene (PP) fibres were characterised by variously arranged steel bar reinforcement: vertically, horizontally, orthogonally and diagonally. The DB1, DBO1 deep beams were conventionally made with steel rod reinforcement but without fibres. The steel wire mesh reinforcement was replaced by fibre reinforcement of varying volume percentages in the remaining deep beams. The influence of the hybrid fibre content in the specimens was studied by marking the development and propagation of cracks, by recording the failure modes, and by monitoring the deflections at the bottom of the deep beam, at the mid-span and at the support. Three-dimensional measurements of strain and displacement of the deep beams without openings (DB) were performed by the non-contact optical 3D deformation measuring system ARAMIS. The experimental results were compared with the studied methods of predicting the shear strength of deep beams reinforced with hybrid fibre. The conducted study demonstrates that hybrid fibres as web reinforcement have a favourable impact on deep beam crack widths and raise the load carrying capacity of deep beams with openings.


2018 ◽  
Vol 12 (8) ◽  
pp. 179 ◽  
Author(s):  
Shereen K. H. Hassan ◽  
Mu`tasim S. Abdel-Jaber ◽  
Maha Alqam

Reinforced concrete structures that incorporates deep beams are generally susceptible to deterioration due to weathering effects and sulphur attacks, under-design in the detailing of concrete cover and/or reinforcement, and construction errors. In lieu of demolishing and replacing these structures, rehabilitation and strengthening using carbon fiber composites becomes a cost-effective viable alternative. Recent advances in research and innovation have introduced concrete repair and strengthening systems that are primarily based on fiber reinforced polymer composites. These systems have offered engineers the opportunity to provide additional stability to the structural elements in question and to restore the damaged portions back to their original load carrying capacity.  This paper investigates the effect of Carbon Fiber Reinforced Polymer (CFRP) composites in enhancing the flexural performance of damaged reinforced concrete deep beams. Two types of CFRP composites and epoxy were used in the experimental investigation carried out and as described by this paper: 1) high strength carbon fiber reinforced polymer (CFRP) plates, commercially known as MBrace Laminate, that are bonded using an epoxy resin specifically suited for the installation and used to strengthen existing structural members; and, 2) MBrace Fiber 230/4900, a 100% solids, low viscosity epoxy material that is used to encapsulate MBrace carbon, glass, and aramid fiber fabrics so that when it cures, it provides a high performance FRP sheet.Test samples were divided into four groups: A control group, and three rehabilitated test groups with CRFP fibers, where the main variable among them was the percent length of CRFP used along the bottom beam extreme surface between supports (i.e, for two of the groups reinforced with MBrace laminates), and the use of MBrace Fiber 230/4500 CRFP sheets on the 4th beam along its vertical sides as well as the bottom extreme face between supports. All beams had similar cross-sectional dimensions and reinforcement, and were designed to fail in flexure rather than shear. The results show that CFRP composites, both laminated and sheet type, have increased the load carrying capacity in comparison to the control specimen, where observations were recorded pertaining to the delayed formation of vertical flexural cracks at the section of maximum moment, and diagonal shear cracks at beam ends. The increase in the load carrying capacity varied among the three rehabilitated test group beams, with the 4th group showing the highest ultimate load carrying capacity when compared to the control specimen. 


2019 ◽  
Vol 5 (1) ◽  
pp. 209 ◽  
Author(s):  
Waleed A. Jasim ◽  
Abbas A. Allawi ◽  
Nazar Kamil Ali Oukaili

This paper presents an experimental and numerical study which was carried out to examine the influence of the size and the layout of the web openings on the load carrying capacity and the serviceability of reinforced concrete deep beams. Five full-scale simply supported reinforced concrete deep beams with two large web openings created in shear regions were tested up to failure. The shear span to overall depth ratio was (1.1). Square openings were located symmetrically relative to the midspan section either at the midpoint or at the interior boundaries of the shear span. Two different side dimensions for the square openings were considered, mainly, (200) mm and (230) mm. The strength results proved that the shear capacity of the deep beam is governed by the size and location of web openings. The experimental results indicated that the reduction of the shear capacity may reach (66%). ABAQUS finite element software program was used for simulation and analysis. Numerical analyses provided un-conservative estimates for deep beam load carrying capacity in the range between (5-21%). However, the maximum scatter of the finite element method predictions for first diagonal and first flexural cracking loads was not exceeding (17%). Also, at service load the numerical of midspan deflection was greater than the experimental values by (9-18%).


2014 ◽  
Vol 13 (3) ◽  
pp. 127-134
Author(s):  
Krystyna Nagrodzka-Godycka ◽  
Anna Knut ◽  
Kamila Zmuda-Baszczyn

The paper presents the results of experimental study carried out by authors on the deep beams with cantilever which was loaded throughout the depth. The main deep beam was directly simply supported on the one side. On the other side the deep beam was suspended in another deep member situated at right angles. All deep beams created a spatial arrangement. The tested deep beams were reinforced orthogonally. Crack patterns and the mode of the failure as well shear concrete were analyzed for their influence on load carrying capacity of the deep beams.


2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.


2005 ◽  
Vol 10 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Z. Kala

The load-carrying capacity of the member with imperfections under axial compression is analysed in the present paper. The study is divided into two parts: (i) in the first one, the input parameters are considered to be random numbers (with distribution of probability functions obtained from experimental results and/or tolerance standard), while (ii) in the other one, the input parameters are considered to be fuzzy numbers (with membership functions). The load-carrying capacity was calculated by geometrical nonlinear solution of a beam by means of the finite element method. In the case (ii), the membership function was determined by applying the fuzzy sets, whereas in the case (i), the distribution probability function of load-carrying capacity was determined. For (i) stochastic solution, the numerical simulation Monte Carlo method was applied, whereas for (ii) fuzzy solution, the method of the so-called α cuts was applied. The design load-carrying capacity was determined according to the EC3 and EN1990 standards. The results of the fuzzy, stochastic and deterministic analyses are compared in the concluding part of the paper.


2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.


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