scholarly journals Review on Columns Dimension and Slab Thickness Effect on Punching Shear Stress in Flat Plate Structures

2020 ◽  
Vol 7 (7) ◽  
pp. 118-122
Author(s):  
Aurang Zaib ◽  
Shabbir Ahmad
Keyword(s):  
Shear Stress ◽  
Flat Plate ◽  
Punching Shear ◽  
Thickness Effect ◽  
Slab Thickness ◽  
Plate Structures

scholarly journals An Analytical and Numerical Investigation on Punching Shear Behaviour of SCC Slab

2016 ◽  
Vol 3 (3) ◽  
Author(s):  
V. Kavinkumar ◽  
R. Elangovan
Keyword(s):  
Shear Stress ◽  
Shear Failure ◽  
Shear Capacity ◽  
Punching Shear ◽  
Shear Behaviour ◽  
Slab Thickness ◽  
Failure Zone ◽  
Self Compacting Concrete ◽  
Concentrated Load ◽  
Different Thickness

<div><p><em>This research is to study the mechanical properties of Self Compacting Concrete (SCC) as well as punching shear failure of SCC slabs. Self compacting concrete was first invited in 1988 to achieve durable concrete structures .Design of Reinforced concrete slab is often compromised by their ability to resist shear stress at punching shear surface area. The connection between slabs and supporting columns could be susceptible to high shear stress and might cause sudden and brittle failure. Punching shear failure takes the form of truncated pyramid shape. This program includes investigating the effect of SCC, slab thickness on the punching shear behaviour in terms of load-deflection response and ultimate failure load, failure characteristic of punching shear failure (shape of failure zone and size of failure zone) of simply supported slabs of 1000 x 1000 x 50 and 75mm under concentrated load at centre of slab. The slabs are made with both SCC and Conventional concrete (CC). Investigation included two way specimens with different thickness to evaluate the performance of specimen with different thickness and the effect of thickness on punching shear capacity and performance</em>.</p></div>

Behaviors of Repaired Edge Column Slab Connections after Punching Failure Using Normal and Non-Shrinkable (CAH) Concrete

2016 ◽  
Vol 845 ◽  
pp. 166-174
Author(s):  
I. Ketut Sudarsana
Keyword(s):  
Flat Plate ◽  
Punching Shear ◽  
Normal Concrete ◽  
Plate Structures ◽  
Shear Damage ◽  
Concrete Mix ◽  
Surface Confinement ◽  
Strength And Stiffness ◽  
Original Strength ◽  
Punching Failure

Column slab connections in flat plate structures are critical part of the structure. Punching shear damage to the connections may occur during construction or post moderate earthquakes. To avoid demolishing overall structures with such damage, connections may be repaired to restore the original strength of the structures. This paper presents behavior of repaired edge column slab connections using normal concrete and non-shrinkable (CAH) concrete. Four edge connections of flat plate structure after failure were repaired using normal and non-shrinkable (CAH) concrete respectively for two connections. The connections were re-tested to fail under combined shear and moment. The results show that bonding agent Sika Top Armatec 110 Epocem gave an excellent bond between the old concrete and the repaired concrete in the tests of repaired edge column slab connection as there are no cracks observed along the concrete interface. The edge connections repaired using normal concrete can have similar strength and stiffness as the original connections when good curing is provided The edge connections repaired using an expansive CAH concrete exhibited less strength and stiffness compared to the original edge connections due to lack of surface confinement. The Superplasticizer used in CAH concrete (Mix. B) improves concrete expansion but reduce the strength of the repaired connections

The Effect of Anchorage Strength with Anchorage Capacity in Flat Plate

2014 ◽  
Vol 627 ◽  
pp. 245-248
Author(s):  
Hyun Ki Choi
Keyword(s):  
Shear Strength ◽  
Flat Plate ◽  
Shear Failure ◽  
Punching Shear ◽  
Slab Thickness ◽  
Shear Reinforcement ◽  
Strength Formula ◽  
Test Result ◽  
Plate System ◽  
Structure Test

The punching shear on the flat plate slab-column connection can bring about the reason of the brittle punching shear failure which may result of collapsing the whole structure. From the development of residential flat plate system, the shear reinforcement is developed for preventing the punching shear. This study proposed 3 reinforcements that are increased to bond capacity using lateral bar, the structure test is performed. As performed test result, because slabs not keep enough bond length, slab is failed before shear reinforcement's yield strength duo to anchorage of slip. According to result, FEM analyzed an effect of slab thickness and concrete compressive. The study suggests shear strength formula that possible a positive shear reinforcement in slab-column connection.

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.

scholarly journals Failure analysis of column–slab connections with stud shear reinforcement

2003 ◽  
Vol 30 (5) ◽  
pp. 934-944 ◽  
Author(s):  
Hong Guan ◽  
Yew-Chaye Loo
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Flat Plate ◽  
Large Scale ◽  
Punching Shear ◽  
Slab Thickness ◽  
Shear Reinforcement ◽  
Element Analysis ◽  
Reinforced Concrete Slabs ◽  
New Type

The design of a flat plate structure is generally governed either by serviceability limits on deflection or punching shear strength of the column–slab connections. To increase the strength of a column–slab connection, a new type of shear reinforcement, referred to as shear stud, is gaining popularity in practice. In this paper, a nonlinear layered finite element method (LFEM) is used to investigate the effectiveness of the shear studs in increasing the punching shear strength of edge and corner column–slab connections. In total, nine large-scale reinforced concrete slabs of a flat plate floor in the vicinity of edge and corner columns, tested previously in the laboratory, are analysed. All the slabs contained stud shear reinforcement (SSR) except a control slab where no SSR was provided. The test variables were the column size and the ratio of stud spacing to slab thickness. The punching shear strengths, load–deflection responses, and crack patterns predicted by the LFEM are compared with the experimental results. The numerical investigation confirms the accuracy and effectiveness of the LFEM in predicting the strength of column–slab connections with SSR.Key words: column–slab connection, concrete flat plate, punching shear, stud shear reinforcement, finite element analysis.

scholarly journals Experimental and analytical evaluation of disproportionate collapse flat-plate buildings

2015 ◽  
Author(s):  
◽  
Zhonghua Peng
Keyword(s):  
Flat Plate ◽  
Shear Capacity ◽  
Punching Shear ◽  
Membrane Phase ◽  
Plate Structures ◽  
Static Tests ◽  
Disproportionate Collapse ◽  
Instantaneous Removal ◽  
Lateral Restraint ◽  
Punching Failure

Reinforced concrete flat plate buildings without continuous integrity reinforcement may be vulnerable to disproportionate collapse if a supporting structural member was lost in an abnormal event. This research forces on the evaluation of potential of disproportionate collapse in older flat-plate structures subjected to the loss of a supporting column in extreme loading events. If a supporting column fails, then the load was carried by that column must be redistributed to the surrounding slab-column connections, which in turn may results in a disproportionate collapse over an entire building or a large portion of it. This progression can occur if the punching shear strength of the surrounding connections is not sufficient. In order to make the most accurate determination of the potential for disproportionate collapse of flat plate structures, this research seeks to accurately evaluation the punching shear capacity of slab-column connections using the conditions present in a potential collapses event. The in-plane lateral restraint provided by the floor slab can enhance the punching shear strength of surrounding slab-column connections and may be significant. In addition, the post-punching capacity of the original failed slab-column connection may reduce the amount of load to be redistributed to the surrounding connections. In order to investigate the effects of lateral restraint and post punching capacity, six restrained and unrestrained static tests was conducted at 1% and 0.64% reinforcement ratios. The static tests showed that the punching shear capacity can be increased 2-8% as lateral restraint stiffness varies from 17 to 75.6kN/mm but the increase is highly related to the in-plane lateral restraint stiffness. The tests also indicated that the slab without integrity reinforcement can develop 54% of maximum post-punching strength after punching. However, this capacity decreases dramatically as the deflection increases to a large amount after punching failure. Since isolated slab-column testing cannot fully represent behaviors of an actual building, multi-panel testing was done at a sub-structure system level. The specimens consisted of two 9 column portion of a flat plate building, one tested with an exterior column instantaneous removal and another tested with an interior column instantaneous removal. The tests further investigated the dynamic load redistribution, punching, and post-punching responses in a flat-plate structure. The multi-panel tests (with interior and exterior column removal) showed that flat-plate slabs are vulnerable to disproportionate collapse at load levels of approximately 50% of their design capacity. The recorded lateral movements on columns in the tests verified the existence of compression membrane forces in continuous slab panel. Compressive membrane forces form after a column removal and gradually transition to tension membrane forces at deflections approaching the slab depth. Punching failure did not happen in compressive membrane phase, but in the tension membrane phase and tests showed that pre-existing damage in flat-plate structures (from prior overloading or shrinkage cracking) may impede the formation of compressive membrane forces in the slab. Dynamic removal of a supporting column resulted in a dynamic load amplification factor (DLAF) of approximately 1.3. Therefore, surrounding connections need to be able to carry at least 30% more than the predicted redistributed static load in a collapse analysis."

Analysis of the Elastic Contact of a Hollow Ball With a Flat Plate

1970 ◽  
Vol 92 (1) ◽  
pp. 138-142 ◽  
Author(s):  
J. H. Rumbarger ◽  
R. C. Herrick ◽  
P. R. Eklund
Keyword(s):  
Shear Stress ◽  
Stress Field ◽  
Flat Plate ◽  
Normal Load ◽  
Thick Wall ◽  
Elastic Contact ◽  
Solid Ball ◽  
Ball Contact ◽  
Contact Life ◽  
Hollow Ball

This paper presents the analysis of the stress field in a hollow sphere in the vicinity of the contact area. The sphere is subjected to a normal load applied through a flat plate. The elastic contact shape and extent are developed for a load of 1000 lb applied to a 1-in-dia hollow ball with a 0.08-in-thick wall. Hollow ball shell bending stresses have a significant effect upon the subsurface stress field. Fatigue life estimates for the hollow ball vary significantly depending upon the selection of decisive stress amplitude. Comparison of the maximum value and location of the reversing orthogonal subsurface shear stress with solid ball data according to the Lundberg-Palmgren dynamic life theory predicts a 91.6 percent life reduction for the hollow ball contact. The use of the unidirectional subsurface shear stress results in a prediction of hollow ball contact life over 30 times the solid ball contact life.

scholarly journals PUNCHING SHEAR STRENGTHS OF HYBRID REINFORCED CONCRETE FLAT PLATE SLABS

2018 ◽  
Vol 2018 (04) ◽  
pp. 101-115
Author(s):  
Suha Rasheed Abass ◽  
◽  
Haitham Jameel Abd ◽  
Keyword(s):  
Reinforced Concrete ◽  
Flat Plate ◽  
Punching Shear
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