Shear Strength Prediction of Reinforced Concrete Deep Beams Using Strut-and-Tie Model

2014 ◽  
Vol 931-932 ◽  
pp. 468-472
Author(s):  
Piyoros Tasenhod ◽  
Jaruek Teerawong

Shear strength prediction of simple deep reinforced concrete beams by method of strut-and-tie model is presented in this paper. The tested specimens were designed according to Appendix A of ACI 318-11 code with variations of shear span-to-effective depth ratios and ratios of horizontal and vertical crack-controlling reinforcement. Test results revealed that at the same shear span-to-effective depth ratio, the various crack-controlling reinforcements significantly influenced on strength reduction coefficients of strut and failure modes. When the shear span-to-effective depth ratios were increased, failure modes changed from splitting diagonal strut to flexural-shear failure. Based on the test results, the proposed model was compared with Appendix A of ACI 318-11code.

2014 ◽  
Vol 931-932 ◽  
pp. 473-477
Author(s):  
Prach Amornpinnyo ◽  
Jaruek Teerawong

This paper presents the test results on the shear behavior of reinforced concrete deep beams with six steel reinforcement configurations. They were designed in accordance with the method given in the ACI 318-11. The specimens were subjected to the single concentrated loading at mid-span. The horizontal to vertical reinforcement ratios and shear span-to-effective depth ratios were the variables studied. The shear span-to-effective depth ratios of the beam specimen were between 1.5 to 2.0. The strut-and-tie model was used for the analysis. The test results indicated that the first diagonal cracking load and the failure mode were controlled by the horizontal to vertical reinforcement ratios and the shear span-to-depth ratios. The tests consistently gave the strength values slightly less than those calculated by using the ACI model. A modified ACI model for strut-and-tie was thus proposed and was found to accurately fit the experimental results.


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.


2018 ◽  
Vol 21 (1) ◽  
pp. 86
Author(s):  
Ahmed Faleh Al-Bayati

This paper presents a simple strut and tie model to calculate the shear strength of reinforced concrete deep beams. The proposed model assumes that the shear strength is the algebraic sum of three strength components: concrete diagonal strut, vertical stirrups, and horizontal web reinforcements. The contribution of each strength components was calibrated with the test results of 305 deep beams compiled from previous studies with wide range of geometrical and material properties. The predictions of the proposed model were compared with those of the current codes of practice (ACI-318-14 and ASHTOO 2014) and those of existing model in the literature. Comparisons revealed that the proposed model provided better predictions than other models. The mean of predicted strength to test of the proposed model, the ACI-318-14 model, the ASHTOO 2014 model were 0.98, 0.79, and 0.75, respectively. The corresponding standard deviations were 0.17, 0.28, and 0.49, respectively.


2017 ◽  
Vol 12 (2) ◽  
pp. 39-45 ◽  
Author(s):  
Pavlo Vegera ◽  
Rostyslav Vashkevych ◽  
Roman Khmil ◽  
Zinoviy Blikharskyy

Abstract In this article, results of experimental testing of reinforced concrete beams without transverse shear reinforcement are given. Three prototypes for improved testing methods were tested. The testing variable parameter was the shear span to the effective depth ratio. In the result of the tests we noticed that bearing capacity of RC beams is increased with the decreasing shear span to the effective depth ratio. The design method according to current codes was applied to test samples and it showed a significant discrepancy results. Than we proposed the improved design method using the adjusted value of shear strength of concrete CRd,c. The results obtained by the improved design method showed satisfactory reproducibility.


2015 ◽  
Vol 764-765 ◽  
pp. 1080-1084
Author(s):  
Young Hak Lee ◽  
Hee Cheul Kim ◽  
Ha Eun Park ◽  
Nam Shik Ahn ◽  
Min Sook Kim

This paper deals with the application of Glass Fiber Reinforce Polymer (GFRP) to shear reinforcement for deep beam. Instead of steel stirrup, GFRP shear reinforcement was fabricated in the form of plate with openings and embedded in concrete. An experimental study was performed to evaluate the shear behavior of eight shear reinforced concrete deep beam. Shear test was conducted in which the shear span-to-depth ratio were 1.1, 1.3 and 1.6. Also, shear reinforcement area, and effective depth were considered as variables. Crack patterns, failure modes, and load-displacement were compared in order to evaluate shear strength of the specimens. The effects of these variables on the shear strength of the deep beam were examined. The test results in terms of the shear span-to-depth ratio showed that shear strength increased when the ratio decreased. Also, it showed that shear strength increased as the reinforcement area and the effective depth increased.


2012 ◽  
Vol 226-228 ◽  
pp. 1045-1048 ◽  
Author(s):  
Guo Lin Wang ◽  
Wen Sheng Ding

Two simply supported beams with a shear span to depth ratio of 2.2 were tested, one with straight prestresssing tendons and the other without for reference. The shear behavior and the prestressing effect are focused on. The test results showed that the prestressed concrete (PC) beam has a significant arch effect, and the prestressing could greatly increase both the cracking load and the shear strength. Besides, the Modified Strut-and-Tie Model (MSTM) and the sectional design method from China Code (GB10) and ACI318-08 have also been adopted for predictions. The comparisons indicates that the MSTM can not only well predict the shear strengths of PC beams with a small shear span to depth ratio, but also well account for the prestressing effect, while the sectional design method seems so conservative due to its not properly considering the shear mechanism of such beams. It can be concluded that the MSTM is capable of predicting the shear strength of PC beams with significant arch effect and thus can be employed in practical designs.


Author(s):  
Olaniyi Arowojolu ◽  
Ahmed Ibrahim ◽  
Abdullah Almakrab ◽  
Nicholas Saras ◽  
Richard Nielsen

AbstractThe shear span-to-effective depth ratio (a/d) is one of the factors governing the shear behavior of reinforced concrete (RC) beams, with or without shear reinforcement. In high-strength concrete (HSC), cracks may propagate between the aggregate particles and result in a brittle failure which is against the philosophy of most design guidelines. The experimental results of six HSC beams, with and without shear reinforcement, tested under four-point bending with a/d ranged from 2.0 to 3.0 are presented and compared with different model equations in design codes. The a/d ratio has higher influence on the shear strength of reinforced HSC beams without shear reinforcement than beams with shear reinforcement. Most of the shear resistance prediction models underestimate the concrete shear strength of the beams but overpredict shear resistance of beams with shear reinforcement. However, the fib Model code 2010 accurately predicted the shear resistance for all the beams within an appropriate level of approximation (LoA).


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