scholarly journals Verification of selected calculation methods regarding shear strength in beams without web reinforcement

2018 ◽  
Vol 219 ◽  
pp. 03015
Author(s):  
Marta Hirsz ◽  
Krystyna Nagrodzka-Godycka

The purpose of the article was to compare selected calculation methods regarding shear strength in reinforced concrete beams without web reinforcement. Several calculation methods were tested. This included codes: PN-EN 1992-1-1:2008, ACI 318-14 and fib Model Code for Concrete Structures 2010. The analysis also consists of authorial methods published in technical literature. Calculations of shear strengths were made based on experimental works found in literature. The shear strength ratios Vtest/Vcalc were chosen to be the yardstick of comparison, where Vtest is the experimental shear strength and Vcalc is the calculated shear strength. A wide range of variables including shear span/depth ratio, compressive strength of concrete, longitudinal steel percentage helped to verify the applicability of calculation methods. Although most of authorial techniques proved to be unstable, they succeeded to show that codes’ formulas for shear strength may still be improved. The presented article is a part of Authors’ long term research in the matter and a new chapter of their study now concerning beams without web reinforcement.

2019 ◽  
Vol 2 (2) ◽  
pp. 74-95
Author(s):  
Cindrawaty Lesmana

A wide range of machine learning techniques have been successfully applied to model different civilengineering systems. The application of support vector machine (SVM) to predict the ultimate shearstrengths of reinforced concrete (RC) beams with transverse reinforcements is investigated in thispaper. An SVM model is built trained and tested using the available test data of 175 RC beamscollected from the technical literature. The data used in the SVM model are arranged in a format ofnine input parameters that cover the cylinder concrete compressive strength, yield strength of thelongitudinal and transverse reinforcing bars, the shear-span-to-effective-depth ratio, the span-toeffective-depth ratio, beam’s cross-sectional dimensions, and the longitudinal and transversereinforcement ratios. The relative performance of the SVMs shear strength predicted results were alsocompared to ACI building code and artificial neural network (ANNs) on the same data sets.Furthermore, the SVM shows good performance and it is proved to be competitive with ANN modeland empirical solution from ACI-05.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1711
Author(s):  
Changyong Li ◽  
Na Liang ◽  
Minglei Zhao ◽  
Kunqi Yao ◽  
Jie Li ◽  
...  

This paper is the outcome of experiments on the shear performance of reinforced concrete beams with approved composite-recycled aggregates. The strength grade of composite-recycled aggregate concrete (CRAC) was between 30 MPa and 60 MPa. The shear span-to-depth ratio varied from 1 to 3. The adaptability of HRB400 rebar, with critical yield strength of 400 MPa, used as stirrups was also verified. As the composite technology overcame the shortcomings of recycled coarse aggregate, CRAC had similar mechanical properties with those of conventional concrete. Details on the shear behaviors of test beams under a four-point loading test are presented. The results indicated that the changes of CRAC strain, stirrup strain, and shear-crack width depended on the failure patterns, which are controlled by the shear-span to depth ratio. The stirrups yield at the failure of reinforced CRAC beams. The shear cracking resistance and the shear capacity of reinforced CRAC beams can be predicted by the statistical equations. Based on the design codes GB50010, ACI318-19, Model Code 2010 and DIN-1045-1-2008 for conventional reinforced concrete beams, the shear strengths provided by CRAC and stirrups are statistical analyzed. The rationality of the design equations is examined by the utilization level of shear strength provided by CRAC. The maximum shear-crack widths are extracted from the test data of reinforced CRAC beams at normal service state. Comparatively, by specifying the lower limit of shear strength provided by the CRAC with various shear-span to depth ratios, China code GB50010 gives a rational method for utilizing CRAC. Under the premise that the design of shear capacity would give considerations to meet the normal serviceability, the factored strength of HRB400 rebar should be 360 MPa for the calculation of shear strength provided by stirrups. The design methods in codes of GB50010, ACI318-19 and Model Code 2010 are conservative for the shear capacity of reinforced CRAC beams.


2016 ◽  
Vol 20 (4) ◽  
pp. 582-594 ◽  
Author(s):  
Chan-Yu Jeong ◽  
Hyeong-Gook Kim ◽  
Sang-Woo Kim ◽  
Kang-Seok Lee ◽  
Kil-Hee Kim

It is well known that shear stress at peak of reinforced concrete beams decreases with increasing effective depth. Thus, several existing design codes and models have included various forms of formulas considering the size effect on shear strength of reinforced concrete beams; however, past experimental researches show that tension reinforcement ratio is also associated with the shear strength of reinforced concrete beams. To examine the effect of tension reinforcement ratio and effective depth on shear strength of reinforced concrete beams, this study has conducted experiments in which the effective depth (150, 300, 500, and 780 mm) and tension reinforcement ratio (1%, 2%, and 3%) are employed as variables. Besides, a formula for the shear strength considering both variables is proposed based on data samples collected from the present experiment and previous research. The proposed formula gives predictions comparable to the results of existing shear tests. Furthermore, rational predictions are made for effective depth of beams, compressive strength of concrete, shear span-to-depth ratio, and even tension reinforcement ratio exceeding 3%.


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