scholarly journals Shear Cap Size Selection Method Based on Parametric Analysis of ACI-318 Code and Eurocode 2 Standard

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4938
Author(s):  
Maciej Grabski ◽  
Andrzej Ambroziak
Keyword(s):  
Parametric Analysis ◽  
Load Capacity ◽  
Selection Method ◽  
Shear Capacity ◽  
Punching Shear ◽  
Transverse Reinforcement ◽  
Shear Load ◽  
Reinforced Concrete Structure ◽  
Practical Application ◽  
Eurocode 2

The scope of the paper is to propose a method for determining the size of shear caps in a slab–column-connections-reinforced concrete structure. Usually, shear heads are used to enhance slab–column connection, especially when the transverse reinforcement does not give the required punching shear load capacity. The dimensions of the shear head should provide the punching shear resistance of the connection inside and outside the enhanced region. The process of selecting the size of the shear head is iterative. The parametric analysis of the ACI 318 code and EC2 standard has the objective of indicating which control perimeter (inside or outside the shear head) has a decisive impact on the punching shear capacity of the connection. Based on the analysis, the authors propose methods for selecting the dimensions of the shear head with practical application examples. The paper is intended to provide scientists, civil engineers, and designers with guidelines to design the process of the slab–column connections with the shear caps.

scholarly journals Experimental investigations of punching shear concrete slabs with different types of transverse reinforcement

2014 ◽  
Vol 13 (3) ◽  
pp. 193-200
Author(s):  
Tadeusz Urban ◽  
Łukasz Krawczyk ◽  
Michał Gołdyn
Keyword(s):  
Load Capacity ◽  
Punching Shear ◽  
Experimental Program ◽  
Experimental Investigations ◽  
Concrete Slabs ◽  
Transverse Reinforcement ◽  
Shear Load ◽  
Test Results ◽  
Different Types ◽  
Flexural Reinforcement

The results of support zone thick concrete slabs experimental investigation are presented in the paper. The experimental program consisted of 4 square reinforced concrete flat models to 1:2 scale made of the same concrete with the same dimensions and the same flexural reinforcement. The aim of tests was proved the influence of different transverse reinforcement types on punching shear load capacity. One of the models was a comparative slab made without transverse reinforcement. In the other slabs three types of transverse reinforcement were used: typical stirrups enclosing flexure reinforcement, stirrups situated between flexure reinforcement and ladders. The test results show a few percent difference in load capacity between models with transverse reinforcement, the most effective were typical stirrups enclosing the main reinforcement.

scholarly journals The analysis of the effectiveness of different types of punching shear reinforcement not fully anchored

2013 ◽  
Vol 12 (1) ◽  
pp. 195-202
Author(s):  
Tadeusz Urban ◽  
Michał Gołdyn ◽  
Łukasz Krawczyk
Keyword(s):  
Load Capacity ◽  
Point Of View ◽  
Experimental Results ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Flat Plates ◽  
Eurocode 2 ◽  
Different Types

The paper discusses the issue of load capacity of flat plates with transverse reinforcement situated between the longitudinal reinforcement. Using this types of reinforcement is much more convenient from the installation point of view, however, it does not guarantee complete embedment, as efficient as traditional stirrups that comprise longitudinal reinforcement in compression and the tension zone. The transverse rods do not comprise the main reinforcement, so their slide out of the concrete slabs or cracks parallel to the plane of the longitudinal reinforcement and delamination of the slab can occur. The different types of transverse reinforcement were presented: system consisting of  ready-made bolts, reinforcement baskets or ladders. Experimental results of plates with  these types of reinforcement are presented. The analysis of effectiveness of reinforcement anchorage indicates that transverse bolts can be used to increase the punching shear load capacity of the plates. The resulting capacity was only of about 20% lower than result elements with complete embedment Experimental results were similar to the theoretical capacity resulting from the consideration by Eurocode 2.

scholarly journals Contribution of Transverse Reinforcement Configuration on Concrete Shear Capacity of RC Column

2020 ◽  
Vol 8 (3) ◽  
pp. 127-136
Author(s):  
Taufiq Saidi ◽  
Rudiansyah Putra ◽  
Zahra Amalia ◽  
Munawir Munawir
Keyword(s):  
Axial Load ◽  
Shear Failure ◽  
Shear Capacity ◽  
Transverse Reinforcement ◽  
Shear Load ◽  
Test Results ◽  
Rc Column ◽  
Proper Design ◽  
Compressive Axial Load ◽  
Reinforcement Configuration

Proper design of transverse reinforcement in the RC column is needed to maintain its ability to deform under axial and shear load safely. Even though mandatory building codes for transverse support of the RC column exist, shear failure was still found in the last high earthquake in Pidie, Aceh, in 2016. Therefore, as an attempt to improve RC column strength and elasticity, the effect of transverse reinforcement configuration was evaluated experimentally to a column subjected to an axial and shear load. The experiment was conducted by using four-column specimens with a cross-section 200 x 200 mm. Four types of transverse reinforcement configurations were applied in each column. The test was carried out by loading an axial load always and shear load gradually until its failure. The test results show that the configuration of transverse reinforcement has a significant effect of maintaining column stiffness, which was subjected to compressive axial load and shear load. Furthermore, the arrangement of transverse reinforcement influences the compressive strength significantly and enhance the concrete shear capacity of a column due to its confinement effect.

scholarly journals Theoretical prediction of punching shear capacity of flat slabs without shear reinforcement strengthened by concrete topping

2021 ◽  
Vol 1203 (2) ◽  
pp. 022108
Author(s):  
Daniel Čereš ◽  
Katarína Gajdošová
Keyword(s):  
Shear Resistance ◽  
Design Guidelines ◽  
Shear Capacity ◽  
Reinforcement Ratio ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Model Code ◽  
Flat Slabs ◽  
Eurocode 2 ◽  
Model Code 2010

Abstract The main reasons for strengthening flat slabs are the change of the use of a building, increase in the value of loads, degradation of the concrete cover layer, or insufficient reinforcement. This paper is focused on the assessment of punching shear capacity of the strengthened flat slabs without shear reinforcement. One of the possibilities how to enhance punching shear capacity is the addition of reinforced concrete topping. The main goal of this paper is to compare the possibilities for calculation of the increase in the punching shear capacity by investigation of the influence of different thicknesses of concrete toppings and different reinforcement ratio. A reference specimen is represented by a fragment of a flat slab with the thickness of h = 200 mm supported by circular column with the diameter of 250 mm. Three different thicknesses (50 mm, 100 mm, 150 mm) of concrete toppings were considered together with three different reinforcement ratios for each thickness of concrete overlay. Theoretical predictions of the punching shear resistance of flat slabs were evaluated by design guidelines according to the relevant standards: Eurocode 2 (EN 1992-1-1), Model Code 2010 and draft of the second generation of Eurocode 2 (prEN 1992-1-1). The differences in the influence of reinforcement ratio are significant. In Model Code 2010 the reinforcement ratio in concrete topping was considered in equation of moment of resistance. This is unlike in both of the mentioned Eurocodes, where the reinforcement ratio was assumed as a geometric average value of the original reinforcement ratio in the slab before strengthening and of the reinforcement ratio of concrete topping. All the predicted theoretical calculations are based on the perfect connection and bond between the original and new layer of concrete. These predictions should be verified by experimental investigation, which is going to be prepared shortly. By the additional increase in the thickness of concrete topping or in the amount of added reinforcement the attention should be payed to the limitation of the punching shear resistance by the value of the maximum punching shear resistance in the compression concrete strut.

scholarly journals Punching shear resistance of reinforced concrete footings: evaluation of design codes

2018 ◽  
Vol 11 (2) ◽  
pp. 432-454
Author(s):  
D. F. A. SANTOS ◽  
A. F. LIMA NETO ◽  
M. P. FERREIRA
Keyword(s):  
Reinforced Concrete ◽  
Progressive Collapse ◽  
Shear Resistance ◽  
Test System ◽  
Shear Capacity ◽  
Experimental Results ◽  
Punching Shear ◽  
Complex Method ◽  
Shear Design ◽  
Eurocode 2

Abstract Punching is a possible failure mode for slender footings and it may lead a structure to ruin through progressive collapse. Although footing present different geometric characteristics, their punching shear design is based on the empirical methods used for flat slabs. This paper uses experimental results from 216 tests to evaluate the performance of design code recommendations presented by ACI 318 (2014), ABNT NBR 6118 (2014) and Eurocode 2 (2010) to estimate the punching shear resistance of reinforced concrete footings. Great dispersion between theoretical and experimental results was observed, being evident that the test system affects the punching shear capacity of footings. The more complex method proposed by Eurocode 2 resulted in a better correlation with experimental results.

scholarly journals Strengthening flat slabs without shear reinforcement against punching shear by concrete overlay

2021 ◽  
Vol 1209 (1) ◽  
pp. 012056
Author(s):  
D Čereš ◽  
K Gajdošová
Keyword(s):  
Parametric Study ◽  
Shear Crack ◽  
Shear Resistance ◽  
Shear Capacity ◽  
Reinforcement Ratio ◽  
Punching Shear ◽  
Flat Slab ◽  
Model Code ◽  
Eurocode 2 ◽  
Model Code 2010

Abstract Research in this paper presents a theoretical study of increasing in punching shear capacity of the strengthened flat slab by concrete overlay. The parametric study is based on comparison of three different relevant standards design models and presents results how Eurocode 2 (EN 1992-1-1), Model Code 2010 and draft of second generation of Eurocode 2 (prEN 1992-1-1) take into account strengthening by concrete overlay. A reference specimen is represented by a fragment of a flat slab supported by circular column. Influence of concrete toppings depends on thickness and also on reinforcement ratio. In Eurocode 2 and new generation of Eurocode 2 the increase of punching shear resistance of the slab with concrete topping can be taken into account only by reinforcement ratio and thickness of the slab considering the perfect connection and bond between the original slab and new layer of concrete overlay. Model Code 2010 is based on Critical shear crack theory and the reinforcement ratio in concrete topping was considered in equation of moment of resistance and punching shear resistance is calculated by considering the rotation and deformation of the slab. Estimation of results by parametric study are compared by non-linear model from Atena software.

Punching shear behaviour of geopolymer concrete two-way slabs reinforced by FRP bars under monotonic and cyclic loadings

2022 ◽  
pp. 136943322110523
Author(s):  
Sarwar Hasan Mohmmad ◽  
Mehmet Eren Gülşan ◽  
Abdulkadir Çevik
Keyword(s):  
Cyclic Loading ◽  
Failure Modes ◽  
Load Capacity ◽  
Concrete Strength ◽  
Shear Capacity ◽  
Punching Shear ◽  
Shear Behaviour ◽  
Geopolymer Concrete ◽  
Steel Bars ◽  
Frp Bars

This study examines the punching shear and deflection performance of 16 Geopolymer concrete (GC) two-way slabs subjected to monotonic and cyclic loading by considering the reinforcement material, percentage of reinforcement, type of concrete and the concrete grade. The tested specimens indicated that the crack patterns at the failure and failure modes were almost similar regardless of the type of reinforcement or their ratio. Moreover, the slabs reinforced by fibre-reinforced polymer (FRP) bars exhibited a lower punching capacity than those strengthened by steel bars, even for similar reinforcement ratios. In addition, the results showed that upon increasing the concrete strength and reinforcement ratio, a higher punching shear capacity and lower deflections were obtained under cyclic and monotonic loading. In addition, the punching shear performance of GC slabs was found to be better than that of ordinary concrete (OC), even though both were reinforced by the basalt FRP (BFRP) bar. However, the ultimate load capacity of the slabs was reduced as a result of cyclic loading according to the capacity of the same specimen, resulting from static loading. However, the reduction is very low for slabs reinforced with FRP slabs. Further, the slabs reinforced by FRP had a better fatigue performance compared with slabs reinforced by steel bars with respect to cyclic loading. The results of the tests were also used to evaluate the accuracy of the available punching shear capacity equations.

scholarly journals Investigation of longitudinal reinforcement contribution in shear punching of reinforced concrete flat slabs without transverse reinforcement

2019 ◽  
Vol 279 ◽  
pp. 02005
Author(s):  
Vladimir Alekhin ◽  
Alexander Budarin ◽  
Maxim Pletnev ◽  
Liubov Avdonina
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Load Capacity ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Factors Affecting ◽  
Codes Of Practice ◽  
Reinforced Concrete Slabs

The shear punching of the reinforced concrete slabs is a complex process occurring when considerable force is concentrated on the relatively small area of a column-slab connection. An incorrect assessment of load capacity of slab under the punching shear may lead to an accident. One of the most significant factors affecting the slab capacity is longitudinal reinforcement. In this article much attention is given to the analysis of the longitudinal rebar impact on the maximum loading capacity of reinforced concrete slabs without transverse reinforcement affected by punching shear force using the finite element method. The results obtained via the finite element simulation are compared with laboratory tests and manual calculations carried-out using various methods represented in different national building Codes of practice.

scholarly journals Effect of Shape, Number, and Location of Openings on Punching Shear Capacity of Flat Slabs

Buildings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 484
Author(s):  
Ekkachai Yooprasertchai ◽  
Yonlada Tiawilai ◽  
Theerawee Wittayawanitchai ◽  
Jiranuwat Angsumalee ◽  
Panuwat Joyklad ◽  
...  
Keyword(s):  
Shear Strength ◽  
Standard Deviation ◽  
Experimental Evidence ◽  
Shear Capacity ◽  
Experimental Results ◽  
Punching Shear ◽  
Minimal Impact ◽  
Flat Slabs ◽  
Analytical Results ◽  
Eurocode 2

Experimental evidence have proved that punching shear capacity of flat slabs deteriorate with the presence of openings located within the critical perimeter around columns. It is understood that this deterioration varies inversely with the distance of openings from column’s face. However, effect of the shape of openings on punching shear capacity is not well known. This study presents experimental results of 14 flat specimens to investigate the effects of the number (2 and 4), shape (circular, square, and rectangular), and location (1 and 4 times of slab’s thickness from column’s face) of openings on punching shear strength. It was found that circular openings had least influence on punching capacity followed by square and rectangular openings, respectively. Further, placing openings at a distance of four times the slab’s thickness from column’s face had minimal impact on punching capacity. Further, increasing the number of openings from 2 to 4 substantially reduced the punching capacity. An effort was made to predict the punching capacities of all specimens using the descriptive equations of ACI 318-19 and Eurocode 2. Mean of the ratio of experimental to analytical results and standard deviation of ACI equations were found to be more accurate than those of Eurocode 2 predictions.

scholarly journals Evaluation of punching shear capacity of two-way RC slabs without transverse reinforcement according to different provisions

2021 ◽  
Vol 15 (3) ◽  
pp. 171-184
Author(s):  
Tran Xuan Vinh ◽  
Nguyen Trung Hieu ◽  
Pham Xuan Dat ◽  
Nguyen Manh Hung
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Shear Capacity ◽  
Punching Shear ◽  
Test Results ◽  
Flat Slabs ◽  
Comparison Results ◽  
Eurocode 2 ◽  
Effective Depth ◽  
Rc Slabs

Currently, RC flat slabs are being used commonly because of their advantages. Punching shear failure is one of the governing failure modes of RC flat slabs without column capital and drop panels. In this paper, the provisions for predicting the punching shear capacity of two-way reinforced concrete (RC) flat slabs without shear reinforcement including ACI 318-19, Eurocode 2 and TCVN 5574:2018 provisions are reviewed by mean of considering the influences of the main parameters (effective depth, compressive strength of concrete, loaded area, reinforcement ratio). A total of 169 test results collected from the literature were used to compare with the provisions. The aim of this study was to evaluate the level of applicability of predicting the punching shear capacity of two-way RC flat slabs according to these provisions. The comparison results indicated that the Eurocode 2 provision provides the most accurate prediction of punching shear capacity of two-way RC flat slabs.

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