Optimization of a flat slab with different type of punching reinforcement

2021 ◽  
Vol 16 (1) ◽  
pp. 52-57
Author(s):  
Petra Bujňáková ◽  
Jakub Mečár
Keyword(s):  
Shear Failure ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Flat Slab ◽  
Flat Slabs ◽  
Extreme Load ◽  
New Construction ◽  
New Type ◽  
Shear Reinforcements ◽  
Conventional Type

AbstractSeveral types of punching shear reinforcements are available for increase of the maximum resistance against punching shear failure of flat slabs. Conventional punching shear reinforcement in form of stirrups or double headed studs are in use for decades. They are well known due to their simplicity and good performance. A new type of punching reinforcement has been developed for the case, where the flat slab exposed to extreme load and resistance of conventional type of punching shear reinforcement is not sufficient. Another designs point out that new construction system can reduce the amount of CO2. This paper presents some results of parametric study focused on design of the flat slab using different types of punching shear reinforcement and considering the concrete consumption.

scholarly journals A Comparative Study of Flat Slabs Using Different Shear Reinforcement Parameters

2018 ◽  
Vol 7 (2.20) ◽  
pp. 321
Author(s):  
N Girish ◽  
N Lingeshwaran
Keyword(s):  
Reinforced Concrete ◽  
Brittle Failure ◽  
Shear Failure ◽  
Crack Pattern ◽  
Steel Plates ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Flat Slab ◽  
Flat Slabs ◽  
Four Corners

Punching shear failure is a brittle failure and it is one of the most important types of failure to be considered while designing a reinforced concrete flat slab. This paper aims to study the performance of reinforced concrete flat slabs equipped with different punching shear reinforcement parameters. Three flat slab specimens were cast where two specimens contain punching shear reinforcement in the form of shear stirrups and structural shearbands. The test specimens have length and width of 1000mm and thickness of 185mm for the slabs. The slabs are connected to a column at the center with length and breadth of 300mm and a depth of 700mm. The test specimens were supported by steel plates with length and breadth of 150mm and a thickness of 25mm at the four corners of the slab. The test specimens are loaded on the column face at the top. The deflection, strain and crack pattern were observed and recorded.   

A Method to Predict the Punching Shear Strength of Flat Slabs with Shear Reinforcement Using a Strut-and-Tie Model

2017 ◽  
Vol 738 ◽  
pp. 25-35
Author(s):  
Lukáš Lyčka ◽  
Petr Štěpánek
Keyword(s):  
Shear Failure ◽  
Complex Problem ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Model Code ◽  
Strut And Tie ◽  
Flat Slabs ◽  
Model Code 2010 ◽  
Strut And Tie Model ◽  
Critical Aspects

The use of flat slabs in constructions due to its many functional and economic advantages is wide-spread. Behavior of flat slabs in shear and flexure is a fairly complex problem. Therefore, the punching shear failure belongs to one of the most critical aspects in the design of concrete buildings.The purpose of this paper is to describe a framework of the proposed method for predicting the punching shear of flat slabs with shear reinforcement. Most of the current codes in force are mainly based on empirical formulation. The proposed method is based on a strut-and-tie model and therefore could be considered as an analytical approach. For the purpose of demonstrating the effectiveness of the proposed method, the method is compared with some of the main methods currently in use, such as Eurocode EC2, ACI 318 and Model Code 2010. The comparison consists of results of more than 90 experiments on flat slabs with shear reinforcement, gathered from publications from all around the world.

scholarly journals PERILAKU PUNCHING SHEAR PADA HUBUNGAN KOLOM BULAT DENGAN FLAT SLAB AKIBAT BEBAN TEKAN AKSIAL

2019 ◽  
Vol 1 (1) ◽  
pp. 1-14
Author(s):  
Muhammad Zardi
Keyword(s):  
Concrete Strength ◽  
Load Condition ◽  
Maximum Load ◽  
Shear Capacity ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Eccentric Load ◽  
Flat Slab ◽  
Circular Column ◽  
Flat Slabs

The aim of the tests was to investigate the influence of concrete strength, the eccentricity of the column and the use of shear reinforcement in flat slabs on punching shear. The research specimens are 8 units of flat slabs. Flat slab size 1400 x 1400 mm2 with thickness of 120 mm. Flat slabs were connected with circular column with dimension 225 mm  of diameter and 200 mm of height. Flat slabs were made in to 2 variations of concrete strength, e.i. 30 MPa and 60 MPa, 2 variations of shear reinforcement, e.i. without shear reinforcement and with shear reinforcement and 2 variations of eccentricity that, e.i. without eccentricity and with eccentricity. Each treatment has 1 specimen. Each specimen has 6 cylinder specimens. Cylinder specimens used as a concrete strength control for main specimen (flat slab). The tests showed that the concrete strength had a strong influence on punching shear strength. This is shown by capacity increase of 42.78%; 54.00%; 46.59% and 0.02%. The value is ratio between the maximum load of the specimens with 60 MPa and 30 MPa at the same eccentricity and the same shear reinforcement. The eccentricity of column reduce the capacity of punching shear. This is shown by 3 specimens decrease in capacity of 3.70%; 36.75% and 7.30%. Only 1 specimen that increase in capacity of 9.27%. The value is ratio between the maximum load of the specimens with 40 mm eccentricity and 0 mm eccentricity at the same compressive strenght and the same shear reinforcement. The use of shear reinforcement does not always increase the punching shear capacity. There are 2 observations that increased capacity (52.07% and 65.37% at the centric load) and 2 observations decreased capacity (0.12% and 4.92% at the eccentric load). The value is ratio between the maximum load on the specimens using shear reinforcement with the specimens that do not use shear reinforcement at the same compressive strenght and the same eccentricity.The use of shear reinforcement increase punching shear capacity of flat slab at the centric load condition. The use of shear reinforcement decrease punching shear capacity of flat slab at the eccentric load condition.

scholarly journals New Methods to Resisting Punching Shear Stress in Reinforced Concrete Flat Slabs

2018 ◽  
Vol 8 (02) ◽  
Author(s):  
Fatma M. Eid ◽  
Tayel Magdy ◽  
Ebada Ahmed
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Shear Capacity ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Reinforcement System ◽  
Strength Concrete ◽  
Flat Slabs ◽  
The Difference ◽  
Compact Strength

Punching shear failure is a major problem encountered in the design of reinforced concrete flat slabs. The utilization of shear reinforcement via shear studs or other means has become a choice for improving the punching shear capacity. In this study, a new alternative of reinforcement modalities were tested and demonstrated the effect of self-compact concrete on the punching shear capacity, beside that compared between the difference codes to identify the suitable one for determining the position of critical section of punching shear. Nevertheless, in this investigation, the proposed reinforcement system is examined for interior columns only. An experimental work consisting of six specimens: five of them were cast with normal reinforced concrete and one was cast with self-compact strength concrete. The obtained results indicate that the proposed shear reinforcement system has a positive effect in the enhancement of the punching shear capacity of interior slab–column connection of self-compact strength concrete.

An Experimental Study on Shear Reinforcement Methods of Interior Flat Plate-Column Connections

2008 ◽  
Vol 385-387 ◽  
pp. 857-860
Author(s):  
Hyun Ki Choi ◽  
J.S. Kim ◽  
E.S. Jin ◽  
Chang Sik Choi
Keyword(s):  
Experimental Study ◽  
Flat Plate ◽  
Shear Failure ◽  
Shear Capacity ◽  
Punching Shear ◽  
Vertical Shear ◽  
Shear Reinforcement ◽  
Plate Structures ◽  
Shear Reinforcements ◽  
Plate Column

This research is an experimental study on full-scale interior slab-column connections of flat-plate. Three types of shear reinforcements were proposed to prevent brittle punching shear failure that could result in collapse of whole flat plate structures. A series of four flat plate specimens including a specimen without shear reinforcement and three specimens with the reinforcements was tested. The dimension of the slabs was 2620*2725*180mm and the specimens had a 600*800mm square column at the center of the slabs. The slabs were tested up to failure using monotonic vertical shear forces. The presences of the shear reinforcements substantially increased punching shear capacity and ductility of the interior slab-column connections.

Review of the Punching Shear Behavior of Concrete Flat Slabs in Ambient and Elevated Temperature

2013 ◽  
Vol 4 (4) ◽  
pp. 259-280 ◽  
Author(s):  
Mehrafarid Ghoreishi ◽  
Ashutosh Bagchi ◽  
Mohamed Sultan
Keyword(s):  
Elevated Temperature ◽  
Shear Failure ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Punching Shear ◽  
Ambient Conditions ◽  
Flat Slab ◽  
Flat Slabs ◽  
Analytical Studies ◽  
In Fire

There are a number of benefits associated with two-way concrete flat slab construction for office buildings, parking garages and apartments - for example, reduced formwork, prompt erection, flexibility of partitions, and minimal increase in story heights. However, concrete flat slabs could be quite vulnerable to punching shear failure in the event of a fire. The objective of the present article is to provide a state of the art review of the existing research and the issues associated with concrete flat slabs in fire and elevated temperature. There are a number of experimental and analytical studies on the punching shear behavior of concrete flat slabs in ambient conditions, available in the literature. Based on these studies, it is found that punching shear capacity in ambient condition is affected by many factors, which may not remain constant during a fire exposure. Only a limited number of studies on concrete flat slabs for punching shear failure in fire are available. This paper reviews the available experimental and analytical studies, standards and codes to address the research gap in estimating of punching shear strength of concrete flat slab-column connections without shear reinforcement.

A Study on Shear Reinforcement of Exterior Joints for Flat Plate

2008 ◽  
Vol 385-387 ◽  
pp. 865-868 ◽  
Author(s):  
Hyun Ki Choi ◽  
S.W. Beck ◽  
Y.S. Baik ◽  
Chang Sik Choi
Keyword(s):  
Shear Failure ◽  
Punching Shear ◽  
Control Specimen ◽  
Test Results ◽  
Shear Reinforcement ◽  
Apartment Building ◽  
Gravity Load ◽  
Low Levels ◽  
Shear Reinforcements ◽  
Strength And Ductility

The purpose of this research was to study the response of slab-column connections containing various types of shear reinforcement when subjected to the combination of gravitational and lateral cyclic loads. The three test specimens were full-scale representations of exterior slabcolumn connections of a prototype apartment building in Korea. The control specimen had no shear reinforcements, while the other specimens had CS-Bar and SS-Bar as shear reinforcements. The control specimen failed due to the punching shear around the slab-column connection at 4.0% drift. None of the specimens with shear reinforcement experienced punching shear failure up to 4.4% drift. The two types of slab shear reinforcements proved to be equally effective in resisting punching shear failure of these connections subjected to relatively low levels of gravity load. The presence of shear reinforcements significantly increased the lateral load ductility of the connections. The test results showed that the strength and ductility of the specimens with SS-Bar and CS-Bar were improved by 23% and 15% compared to the specimen without shear reinforcements.

scholarly journals Performance of Shear Reinforcement against Punching Shear Loads

2019 ◽  
Vol 9 (2) ◽  
pp. 841-850
Keyword(s):  
Numerical Study ◽  
Shear Capacity ◽  
Punching Shear ◽  
Slab Thickness ◽  
Test Results ◽  
Shear Reinforcement ◽  
Concentrated Load ◽  
Flat Slab ◽  
Flat Slabs ◽  
Strength Formula

This research targets to maximize the ductility and strength of the reinforced concrete flat slabs. However, to be efficient, the shear reinforcement must be anchored well in the tension and compression zones of the slab. The test results on the slab-column connection models which provided with shear reinforcement are introduced in this study. The benefits of using shear reinforcement are to reduce the slab thickness, and to minimize both the cost and the total weight of the structure. Twelve flat slab specimens have been tested to study the effect of different types of steel RFT on the punching shear of the flat slab. The experimental parameters include no shear reinforcement which study the advantage of using tension RFT ONLY against punching shear, no shear reinforcement which study the advantage of using compression RFT against punching shear, shear RFT (Vertical Stirrups) which study the effect of using shear RFT with constant distribution 0.5d, and a new distribution of shear stirrups which study the effect of using new different width & spacing of vertical stirrups. The twelve specimens were loaded with concentrated load at the mid span until failure. The general behavior of the deformation of the tested slab specimens was examined and recorded (cracking, deflection, and strain in both steel and concrete). A comparison established between the experimental and the numericaltheoretical results obtained from applying the punching shear strength formula given in design codes, and finite element modeling analysis; ABAQUS 2017 software package was used for this analysis. A total of six building codes were examined with regard to their provisions concerning the punching shear. A comparison had been made between the research test results and the codes equations to improve the methods of the analysis about the flat slabs. This study aimed to improve the punching shear capacity of flat slab which leads to more accurate results compared with the codes predictions. To achieve this aim, an experimental and numerical study was carried out for this investigation.

The Maximum Punching Capacity of Flat Slabs

2017 ◽  
Vol 259 ◽  
pp. 232-237
Author(s):  
Lucia Majtánová ◽  
Jaroslav Halvonik ◽  
Ján Hanzel
Keyword(s):  
Experimental Tests ◽  
Shear Resistance ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Flat Slab ◽  
Flat Slabs ◽  
Punching Failure

Two ways how to determine maximum punching resistance of flat slabs with shear reinforcement are currently used. The first way is verification of the concrete strut capacity at the column periphery defined as VRd,max. The second limit is defined as kmax multiple of the punching shear resistance without shear reinforcement VRd,c. The values of kmax are proposed usually in between 1.4 and 2.0. Results of the experimental tests are presented in the paper that were focused on above mentioned limits, whether failure of the struts can precede any other form of punching failure that is limited by kmax*VRd,c. Two experimental slab samples reinforced with high amount of shear reinforcement that increased punching capacity above capacity of the concrete struts were tested together with two slab samples cast without shear reinforcement. Comparison has shown that punching resistance of flat slab with shear reinforcement has been 1.7 times higher than resistance without shear reinforcement. While some standards allow for use kmax value of 1.9 in this case. This indicates that limits based only on the kmax factors may overestimate actual maximum punching shear resistance.

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