scholarly journals Effect of shear span-to-depth ratio on posttensioned concrete crane beams shear capacity

2020 ◽  
Vol 323 ◽  
pp. 01019
Author(s):  
Wit Derkowski ◽  
Rafał Walczak

The shear span-to-depth ratio has the most significant influence on the shear capacity of beams and determines their failure mode. The subject of the current project is the shear capacity of precast posttensioned concrete crane beams disassembled after more than fifty years of being used in an industrial plant. The paper gives the theoretical basis for the shear capacity of such elements as well as standard design models. The conducted tests showed that despite the low shear reinforcement ratio, the elements do not fail in a brittle mode but show a clear indication of prospective destruction. It was also confirmed that in the case of poorly shear-reinforced PC elements, a clear arch action can be distinguished with a low shear span-to-depth ratio, whereas in the case of a higher ratio there is a classical beam action.

2012 ◽  
Vol 41 ◽  
pp. 294-306 ◽  
Author(s):  
Giuseppe Campione ◽  
Giovanni Minafò
Keyword(s):  

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1218 ◽  
Author(s):  
Jun-Hong Zhang ◽  
Shu-Shan Li ◽  
Wei Xie ◽  
Yang-Dong Guo

This study aimed to investigate the shear capacity performance for eight deep beams with HTRB600 reinforced high strength concrete under concentrated load to enable a better understanding of the effects of shear span–depth ratio, longitudinal reinforcement ratio, vertical stirrup ratio and in order to improve design procedures. The dimension of eight test specimens is 1600 mm × 200 mm × 600 mm. The effective span to height ratio l0/h is 2.0, the shear span–depth ratio λ is 0.3, 0.6 and 0.9, respectively. In addition, the longitudinal reinforcement ratio ρs is set to 0.67%, 1.05%, 1.27%, and the vertical stirrup ratio is taken to be 0%, 0.25%, 0.33%, 0.5%. Through measuring the strain of steel bar, the strain of concrete and the deflection of mid-span, the characteristics of the full process of shear capacity, the failure mode and the load deflection deformation curve were examined. The test results showed that the failure mode of deep beams with small shear span–depth ratio is diagonal compression failure, which is influenced by the layout and quantity of web reinforcement. The diagonal compression failure could be classified into two forms: crushing-strut and diagonal splitting. With decreasing of shear span–depth ratio and increasing longitudinal reinforcement ratio, the shear capacity of deep beams increases obviously, while the influence of vertical web reinforcement ratio on shear capacity is negligible. Finally, the shear capacity of eight deep beams based on GB 50010-2010 is calculated and compared with the calculation results of ACI 318-14, EN 1992-1-1:2004 and CSA A23.3-04, which are based on strut-and-tie model. The obtained results in this paper show a very good agreement with GB50010-2010 and ACI 318-14, while the results of EN 1992-1-1:2004 and CSA A23.3-04 are approved to be conservative.


2012 ◽  
Vol 217-219 ◽  
pp. 2435-2439
Author(s):  
Ying Tao Li ◽  
Shi Yong Jiang ◽  
Bing Hong Li ◽  
Qian Hua Shi ◽  
Xian Qi Hu

An experimental program was carried out by the author to investigate the shear behavior of concrete beams reinforced with continuous FRP rectangular spirals, the main variables considered in the test were the shear reinforcement ratio and the shear span to depth ratio and the longitudinal reinforcement ratio. However, the experimental program is inadequate to gain insight into the shear behavior of the members. First, the quantities of test specimens were too small, only six beams were made and tested, the experimental database was so limited that the resultant analytical results and conclusions may not be sound enough. Second, not all the main factors that have influences on the shear behavior of the members have been treated as variables in the experimental program, such as the effective transverse compression stress and the concrete compression strength, the influences of these two factor on the shear behavior of the members were not clear yet through the experimental study. Considering the insufficient information provided by the experimental investigation, the parametric analysis of the shear behavior of the members was carried out, and a revised rotating-angle softened truss model for the shear analysis of the members was proposed as the analytical tool. Based on the proposed model, the influences of various factors on the shear capacity and shear failure modes of the members were discussed, related nonlinear analysis was carried out using the arithmetic of iteration and step approximation, and several FORTRAN codes were written accordingly. Through the experimental study and the parametric analysis, it is indicated that the shear capacity and the shear failure modes of the members are greatly influenced by three major factors, including the shear reinforcement ratio and the shear span to depth ratio and the effective transverse compression stress. The influences of the concrete compression strength and the longitudinal reinforcement ratio on the shear capacity are not noticeable comparatively. The shear capacity is little affected by the shear span to depth ratio in the case of the shear-tension failure, there is no noticeable correlation between longitudinal reinforcement ratio and the shear failure modes.


2019 ◽  
Vol 2 (1) ◽  
pp. p43 ◽  
Author(s):  
Hussain Naser Hussain ◽  
Qasim M. Shakir

In this study, the structural behavior and performance of the dapped end beams with composite section under effect of static and repeated loads was investigated by experimentally tested and included ten simply supported beams with dapped in one of ends. The parameters that have been taken into consideration represented by studying the effect of reparation longitudinal tensile reinforcement by steel sections, effect of repeated loads, different types of composite steel sections, and influence of increased the shear span to depth ratio (a/d) more than one on the composite dapped end region. The study focused on determining the first cracking load, ultimate strength (Pu), deflection at service and ultimate load, failure mode, load-deflection behavior, ductility ratios, and crack pattern at failure load. The results presented that using the composite I-section instead of normal section in dapped end beams developed the shear capacity for dapped end region and enhanced the first crack appearances about 33.33, and 39.42 % for shear span to depth ratio 1.0, and 1.5 respectively.


Author(s):  
Muhammad K. Kayani ◽  
Wasim Khaliq ◽  
Muhammad K. Shehzad

Major factors contributing to the shear behavior in reinforced concrete (RC) beams have been identified as compressive strength of concrete, shear span to effective depth ratio, and longitudinal reinforcement. Though significant, few of these factors are not fully incorporated in ACI code provisions for design of minimum shear reinforcement. To investigate the effect of these parameters, an analytical and experimental study was undertaken on the shear behavior of ordinary strength RC slender beams with moderate longitudinal reinforcement. The experimental program consisted of testing of eight simply supported RC slender beams subjected to two concentrated loads at a shear span to depth ratio (a/d) of 2.5 and equipped with varying shear reinforcement according to four different criteria. Ultimate shear strengths obtained in this experimental program are compared to the analytical shear strengths calculated according to existing as well as proposed equations. Test results exhibit that, the modified equation proposed in this work gives more accurate prediction of shear capacity of RC beams.


2021 ◽  
Vol 15 (57) ◽  
pp. 321-330
Author(s):  
Marta Słowik

The analysis of fracture processes which led to shear failure in reinforced concrete beams without transverse reinforcement was performed on the basis of test results from the author’s own experimental investigation and numerical simulations. The variable parameters during the experiment were a beam’s length and a shear span. It was observed that the character of failure in the beams depended on the beam’s length and the span-to-depth ratio. In slender beams characterized by the shear span-to-depth ratio 3.4 and 4.1, the formation of the critical diagonal crack caused a brittle, sudden failure and the shear capacity was low. In short beams, when the shear span-to-depth ratio was 1.8 and 2.3, the failure process had a more stable character with a slow developing of inclined cracks and the significantly higher load capacity was reached. The activation of various shear transfer mechanisms was examined with regard to the slenderness of the member and the transition between a beam action which took place in slender beams to an arch action which predominated in short beams was described.


2021 ◽  
pp. 136943322110093
Author(s):  
Zhenzhen Liu ◽  
Yiyan Lu ◽  
Shan Li ◽  
Jiancong Liao

A comprehensive study of the shear characteristics of steel fiber reinforced recycled concrete-filled steel tube (SRCFST) columns is conducted. 50 CFST stub columns are tested with the variables of steel tube diameter-thickness ratio ( D/t), shear span-to-depth ratio (λ), axial compression ratio ( n), and concrete mix. Two types of cements, three recycled aggregate percentages, three water-cement ratios, and three steel fiber contents are considered in design of concrete mixes. The experimental results show that SRCFST columns present the coincident shear behavior of the ordinary CFST columns. As λ is increased, shear resistance shows a downtrend, while the flexural strength presents an increasing trend. Imposing axial compression or thickening steel tube contributes to an adequate safety margin in plastic period. Based on the contributions superposition method, a predicted model of the shear capacity of SRCFST columns is proposed in consideration of shear-span ratio, axial compression, and self-stress.


2021 ◽  
Vol 6 (7) ◽  
pp. 97
Author(s):  
Stefanus Adi Kristiawan ◽  
Halwan Alfisa Saifullah ◽  
Agus Supriyadi

Deteriorated concrete cover, e.g., spalling or delamination, especially when it occurs at the web of a reinforced concrete (RC) beam within the shear span, can reduce the shear capacity of the beam. Patching of this deteriorated area may be the best option to recover the shear capacity of the beam affected. For this purpose, unsaturated polyester resin mortar (UPR mortar) has been formulated. This research aims to investigate the efficacy of UPR mortar in limiting the shear cracking and so restoring the shear capacity of the deteriorated RC beam. The investigation is carried out by an experimental and numerical study. Two types of beams with a size of 150 × 250 × 1000 mm were prepared. The first type of beams was assigned as a normal beam. The other was a beam with a cut off in the non-stirrup shear span, which was eventually patched with UPR mortar. Two reinforcement ratios were assigned for each type of beams. The results show that UPR mortar is effective to hamper the propagation of diagonal cracks leading to increase the shear failure load by 15–20% compared to the reference (normal) beam. The increase of shear strength with the use of UPR mortar is consistently confirmed at various reinforcement ratios.


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