Punching shear strength of slab-column connections in flat plate system

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.

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Punching Shear Strength Characteristics of Flat Plate Panels Reinforced with Shearhead Collars: Experimental Investigation

Civil Engineering Journal ◽

10.28991/cej-2019-03091265 ◽

2019 ◽

Vol 5 (3) ◽

pp. 528 ◽

Cited By ~ 1

Author(s):

Maroua Mohammed Majeed ◽

Aamer Najim Abbas

Keyword(s):

Experimental Investigation ◽

Shear Strength ◽

Reinforced Concrete ◽

Flat Plate ◽

Energy Absorption ◽

Concrete Slab ◽

Shear Capacity ◽

Load Test ◽

Punching Shear ◽

Reference Specimen

This paper presents an experimental investigation on the punching shear strength of reinforced concrete flat plate slabs with shearhead collars. Eight reinforced concrete slab specimens were casted and tested under static load test, the load was applied at the center of slab by 100x100 mm steel column. The effect of the shapes, diameter and number of stiffeners has been discovered for shearheads through studying its effect on the load-deflection behavior, ultimate capacity, cracking load, failure mode, stiffness, ductility and energy absorption of tested specimens. The experimental results indicates that using square shearhead had achieved a slight increase in punching shear strength about 3% over that circular shearhead using the same surface area. Also, utilize 550 mm shearhead diameter will contribute to increase the punching shear strength about 14.5%. The increase in the number of stiffeners in specimen (CS4) had reduced the ultimate punching shear capacity by 20.3% over reference specimen. The first crack was decreased from 12.5kN to 7.5kN, when increases the number of stiffeners from one to two. The cracking load was increased with the increase of the diameter of circular shearhead from 10kN to 15Kn in specimens of 336mm and 550mm respectively. The specimen with 336mm diameter and 30mm height circular shearhead achieved 427 kN.m energy absorption, it is higher than the energy absorption of reference specimen by 2.6%. Also, using two stiffeners improved the energy absorption by 110.2% higher than the specimen with one stiffener.

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Effective Critical Section Evaluation of a Reinforced Concrete Flat-Plate Slab with Openings for its Punching Shear Strength Estimation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.764-765.1164 ◽

2015 ◽

Vol 764-765 ◽

pp. 1164-1169

Author(s):

Dae Jin Kim ◽

Jong Hwan Park ◽

Tae Hun Ha

Keyword(s):

Shear Strength ◽

Reinforced Concrete ◽

Flat Plate ◽

Numerical Algorithm ◽

Critical Section ◽

Direct Application ◽

Punching Shear ◽

Design Codes ◽

Critical Sections ◽

Section Evaluation

Most of current concrete design codes require that critical sections should be reduced in the presence of openings near columns to consider their effects on the punching shear strength of reinforced concrete flat-plate slabs. For example, ACI 318-11 stipulates that a part of the perimeter enclosed by two projection lines from the centroid of the column to the boundaries of the openings shall be considered ineffective. However, the direct application of this rule to practical cases may be rather complicated depending on the geometrical layout and shape of columns and openings. In this paper, simple mathematical formulations are proposed to evaluate the ineffective part of critical sections due to openings. This approach can be applied to the design of reinforced concrete flat-plate slabs based on ACI 318-11. A numerical algorithm is also developed to handle general cases where the ineffective parts of multiple openings overlap with each other.

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Failure analysis of columnslab connections with stud shear reinforcement

Canadian Journal of Civil Engineering ◽

10.1139/l03-058 ◽

2003 ◽

Vol 30 (5) ◽

pp. 934-944 ◽

Cited By ~ 7

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 columnslab connections. To increase the strength of a columnslab 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 columnslab 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, loaddeflection 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 columnslab connections with SSR.Key words: columnslab connection, concrete flat plate, punching shear, stud shear reinforcement, finite element analysis.

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Finite element analysis of the effect M/V ratios on punching shear strength of edge slabcolumn connections of flat plate structure

MATEC Web of Conferences ◽

10.1051/matecconf/201927601012 ◽

2019 ◽

Vol 276 ◽

pp. 01012

Author(s):

I Ketut Sudarsana ◽

I Gede Gegiranang Wiryadi ◽

I Gede Adi Susila

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Shear Strength ◽

Flat Plate ◽

Nonlinear Behavior ◽

Punching Shear ◽

Element Analysis ◽

Plate Structure ◽

Concrete Damage ◽

Good Agreement

The occurrence of unbalanced moment in edge slab-column connections of flat plate structure cannot be avoided and increase the slab shear stress around the column. This paper investigates the effect of M/V ratio on punching shear strength of edge column-slab connections using finite element analysis. The Concrete Damage Plasticity (CDP) and truss model in Abaqus were used to model the nonlinear behavior of concrete and reinforcement, respectively. Ten values of the M/V ratio were applied to a subassembly edge connection model which was part of a properly design of a 5 story flat plate structure. The shear strength prediction of ACI 318-14 code on the effect of unbalanced moment in edge column-slab connection was also studied. The analysis results show that the effect of unbalanced moment on shear strength is not significant for M/V ratio less than 0.3. However, for M/V ratio greater than 0.3, the shear strength is reduced in an exponential order. The ACI 318-14 code overestimates prediction on connection’s shear strength for the M/V ratio less than 0.3. The code predictions are in a good agreement with the analysis results for the edge connection with the M/V ratio greater than 0.3.

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