Shear strength of prestressed concrete edge slab–column connections with and without shear stud reinforcement

1989 ◽  
Vol 16 (6) ◽  
pp. 807-819 ◽  
Author(s):  
Walter H. Dilger ◽  
Marwan Shatila
Keyword(s):  
Shear Strength ◽  
Key Words ◽  
Prestressed Concrete ◽  
Concrete Slab ◽  
Test Results ◽  
Shear Reinforcement ◽  
Flat Slabs ◽  
Unbonded Tendons ◽  
Reinforcement Design ◽  
Strength And Ductility

Results are reported of tests to failure on six full-scale unbonded post-tensioned prestressed concrete slab–edge column specimens. The objective is to study experimentally the strength and behaviour of this type of connections. The variables are quantity and distribution of stud shear reinforcement and length of overhang. The relevant design equations suggested by Dilger and Ghali as well as several models by others for predicting the strength of prestressed concrete slab–edge column connections are compared with test results. It is concluded that the ACI and CSA provisions for predicting the strength of such connections are conservative, and that the presence of stud shear reinforcement is a good means of increasing the strength and ductility of this type of connections. Key words: shear strength, flat slabs, prestressed concrete, unbonded tendons, shear reinforcement, design, ductility.

scholarly journals Punching Shear Strength of Reinforced Concrete Flat Plates with GFRP Vertical Grids

2021 ◽  
Vol 11 (6) ◽  
pp. 2736
Author(s):  
Min Sook Kim ◽  
Young Hak Lee
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Fiber Reinforced Polymer ◽  
Punching Shear ◽  
Test Results ◽  
Shear Reinforcement ◽  
Flat Plates ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Vertical Grids

In this study, the structural behavior of reinforced concrete flat plates shear reinforced with vertical grids made of a glass fiber reinforced polymer (GFRP) was experimentally evaluated. To examine the shear strength, experiments were performed on nine concrete slabs with different amounts and spacings of shear reinforcement. The test results indicated that the shear strength increased as the amount of shear reinforcement increased and as the spacing of the shear reinforcement decreased. The GFRP shear reinforcement changed the cracks and failure mode of the specimens from a brittle punching to flexure one. In addition, the experimental results are compared with a shear strength equation provided by different concrete design codes. This comparison demonstrates that all of the equations underestimate the shear strength of reinforced concrete flat plates shear reinforced with GFRP vertical grids. The shear strength of the equation by BS 8110 is able to calculate the punching shear strength reasonably for a concrete flat plate shear reinforced with GFRP vertical grids.

Effects of reinforcing elements on the behavior of weakly cemented sands

1988 ◽  
Vol 25 (2) ◽  
pp. 389-395 ◽  
Author(s):  
Loretta Li ◽  
Robert Mitchell
Keyword(s):  
Shear Strength ◽  
Key Words ◽  
Plane Strain ◽  
Failure Strain ◽  
Test Results ◽  
Cemented Sand ◽  
Mine Backfill ◽  
Unreinforced Material ◽  
Behavior Mining ◽  
Cement Mixture

Plane strain test results from weakly cemented sand samples with various types of reinforcement inclusions are reported. Mesh and anchored fibre types of reinforcements are shown to more than double the plane strain shear strength of a 33:1 sand–cement mixture. Other types of inclusions were not as effective, with some actually producing a strength decrease. All inclusions increased the ductility of this weakly cemented sand, allowing the material to absorb strains of 4–6% rather than the 0.5 – 1% of failure strain in the unreinforced material. The application of reinforcements to cemented tailings used for mine backfill is briefly discussed. Key words: reinforced backfill, cemented sand, behavior, mining.

Rehabilitation of reinforced concrete slab–column connections

2002 ◽  
Vol 29 (4) ◽  
pp. 602-611 ◽  
Author(s):  
Ehab F El-Salakawy ◽  
Maria Anna Polak ◽  
Khaled A Soudki
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Concrete Slab ◽  
Normal Weight ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Shear Reinforcement ◽  
Reinforced Concrete Slab ◽  
Normal Weight Concrete ◽  
Average Compressive Strength

The paper presents work on punching shear rehabilitation and strengthening of existing slab–column connections. Four full-scale specimens representing slab–column edge connections were built and tested to failure. Three slabs were then repaired and strengthened and tested again. In the originally tested slabs, which were chosen for repair, one slab had an opening in front of the column and contained shear reinforcement, one slab had an opening and no shear reinforcement, and one had no opening and no reinforcement. The dimensions of the slabs were 1540 × 1020 × 120 mm with square columns (250 × 250 mm). The openings in the specimens were square (150 × 150 mm) with the sides parallel to the sides of the column. The slabs were made using normal weight concrete (28-day average compressive strength of 32 MPa) and reinforced with a reinforcement ratio of 0.75%. The slabs were repaired by replacing old-damaged concrete with new concrete of the same properties. Strengthening was carried out using shear studs for the two slabs, which originally did not have shear reinforcement. The rehabilitation increased the punching shear strength (by 26–41%) and the ductility of the connections. All repaired specimens failed in flexure.Key words: concrete slabs, punching shear, rehabilitation, edge connections, openings, studs, repair.

Shear Strength of Concrete Wide Beams Shear Reinforced with GFRP Plates

2018 ◽  
Vol 26 (1) ◽  
pp. 111-118
Author(s):  
Min Sook Kim ◽  
Joowon Kang ◽  
Young Hak Lee
Keyword(s):  
Shear Strength ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Shear Reinforcement ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Shear Performance ◽  
Wide Beams ◽  
Better Than

This paper discusses the experimental results on the shear behavior of concrete wide beams reinforced with glass fiber reinforced polymer (GFRP) plates as shear reinforcement. In order to examine the shear performance, a total of six concrete wide beams were manufactured and tested. All the specimens were designed to have the same number of legs of shear reinforcement. The transverse spacing of shear reinforcement was considered as a variable to investigate the influence of transverse spacing of concrete wide beams. From the test results, it is observed that the shear strength increased when transverse spacing of the shear reinforcement decreased. In addition, an equation is proposed to predict the shear strength of concrete wide beams in order to consider the influence of transverse spacing of the shear reinforcement. The equation is based on the test results and modified ACI 318–14. It is verified that the proposed equation is considered to be better than ACI 318–14.

scholarly journals Experimental and numerical investigation of post-tensioned concrete flat slabs in fire

2016 ◽  
Vol 7 (1) ◽  
pp. 2-18 ◽  
Author(s):  
Ya Wei ◽  
Francis T.K. Au ◽  
Jing Li ◽  
Neil C.M. Tsang
Keyword(s):  
High Strength ◽  
Test Results ◽  
Self Compacting Concrete ◽  
Content Type ◽  
Moisture Contents ◽  
Flat Slabs ◽  
Unbonded Tendons ◽  
In Fire ◽  
Fire Conditions ◽  
Post Tensioned

Purpose This paper aims to understand the structural fire performance of two-way post-tensioned flat slabs, particularly their deformations and load-carrying mechanisms in fire, and to explore the behaviour of post-tensioned high-strength self-compacting concrete flat slabs with unbonded tendons in fire. Design/methodology/approach Four tests of post-tensioned high-strength self-compacting concrete flat slabs were conducted under fire conditions. Numerical modelling using the commercial package ABAQUS was conducted to help interpret the test results. Findings Two of the specimens with lower moisture contents demonstrated excellent fire resistance performance, while the others with slightly higher moisture contents experienced severe concrete spalling. Originality/value The test results were discussed in respect of thermal profiles, deflections, crack patterns and concrete spalling. The performance of post-tensioned high-strength self-compacting concrete flat slabs with unbonded tendons under fire conditions was better understood.

Punching shear provisions for reinforced and presfressed concrete flat slabs

1996 ◽  
Vol 23 (2) ◽  
pp. 502-510 ◽  
Author(s):  
N. J. Gardner
Keyword(s):  
Reinforced Concrete ◽  
Correction Factor ◽  
Prestressed Concrete ◽  
Shear Capacity ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Flat Slabs ◽  
Reinforced Concrete Slabs ◽  
Unbonded Tendons ◽  
Effective Depth

The validity of the CSA A23.3-94 code provisions for punching shear were compared with the punching shear results of 142 reinforced concrete flat slabs, 16 prestressed concrete flat slabs with unbonded tendons, and 17 flat slabs with unbonded prestressed and supplementary bonded reinforcement. The code prediction equations are not capable of direct verification against experimental results without using a correction factor. Using a justifiable correction factor, the CSA A23.3-94 provisions are appropriately conservative for reinforced concrete slabs but the scatter is large. However, it was concluded that the CSA A23.3-94 provisions are not conservative for prestressed concrete flat slabs. An equation is proposed to calculate the punching shear capacity of reinforced concrete and prestressed concrete slabs, which has a smaller coefficient of variation than the punching shear provisions of CSA A23.3-94, for symmetrically loaded interior columns. The critical section of the proposed method is the perimeter of the column, which is easier to justify than an arbitrary critical perimeter half the effective depth of slab from the column. Key words: reinforced concrete, prestressed concrete, flab slabs, punching shear.

Study on Prestressed Concrete Slabs with Lightweight Aggregate

2012 ◽  
Vol 450-451 ◽  
pp. 338-342
Author(s):  
Ming Jie Mao ◽  
Qiu Ning Yang
Keyword(s):  
Shear Strength ◽  
Prestressed Concrete ◽  
Lightweight Concrete ◽  
Concrete Slab ◽  
Lightweight Aggregate ◽  
Punching Shear ◽  
Lightweight Aggregate Concrete ◽  
Concrete Slabs ◽  
Low Permeability ◽  
Aggregate Concrete

A lightweight aggregate with low permeability was employed in the concrete slab; and the strength of the slab is mainly discussed. The purpose of present study is to evaluate experimentally the punching shear strength of lightweight concrete slab, and to propose the punching shear strength equation for the slab with lightweight aggregate concrete. The applicability of the proposed equation to the both reinforced concrete and pre-stressed concrete slabs with lightweight aggregate concrete.

Beams prestressed with unbonded tendons at ultimate

1996 ◽  
Vol 23 (6) ◽  
pp. 1220-1230 ◽  
Author(s):  
Marco Andrea Pisani ◽  
Emilio Nicoli
Keyword(s):  
Numerical Analysis ◽  
Key Words ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Experimental Tests ◽  
Safety Factors ◽  
Unbonded Tendons ◽  
External Tendons ◽  
Simplified Method ◽  
Good Agreement

This paper presents a numerical investigation on beams and slabs prestressed with either unbonded internal or external tendons. Twenty-three experimental tests (beams and slabs prestressed with unbonded internal tendons) were numerically simulated to verify the reliability of the numerical algorithm adopted. The good agreement established enables us to study the behaviour of these beams in depth and to compare it with the behaviour of similar beams prestressed with external tendons. The numerical analyses were then repeated after including the safety factors related to the materials. The outputs were then compared with the results adopted by making use of the simplified method suggested by Eurocode E.C.2 Part 1-5, to check the size of the error involved in the adoption of the latter. Key words: numerical analysis, unbonded internal tendons, external tendons, European Prestandard, prestressed concrete, beams, post-tensioned.

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