Effect Of Reinforcement Ratio On Punching Shear Strength Of Reactive Powder Concrete Slab Reinforced With CFRP Bars

2017 ◽  
pp. 1
Author(s):  
Abdul Muttalib I. Said ◽  
Samir M. Chasib
Keyword(s):  
Shear Strength ◽  
Concrete Slab ◽  
Reinforcement Ratio ◽  
Punching Shear ◽  
Reactive Powder Concrete ◽  
Reactive Powder

scholarly journals Effect of Hospital Effluents and Sludge Wastewater on Foundations Produced from Different Types of Concrete

2019 ◽  
Vol 5 (4) ◽  
pp. 819-831 ◽  
Author(s):  
Aamer Najim Abbas ◽  
Lubna M. Abd ◽  
Muhannd W. Majeed
Keyword(s):  
Shear Strength ◽  
Fresh Water ◽  
Domestic Wastewater ◽  
Punching Shear ◽  
Reactive Powder Concrete ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Hospital Effluents ◽  
Normal Strength ◽  
Reactive Powder

In last decades, there is an insufficiency of fresh water and construction works are increasing day by day consuming large amount of fresh water. Therefore research is processing on to employ the treated domestic wastewater in the preparation and curing of concrete. In this investigation, the concrete slab specimens casted with normal strength concrete and modified reactive powder concrete. The concrete specimens cast by using fresh water, wastewater, and hospital effluents water. The specimens cured in all water types for 28days and 56 days. At 28days curing with wastewater, a decrease in punching shear strength was observed from 24 kN in case of curing with fresh water to 21 kN and 20 kN in case of curing with wastewater and hospital effluents water respectively. Highest strength is exhibited by 56 days curing age, it was recorded about 32 kN, 24 kN and 23 kN punching shear strength of specimens cured with fresh water, wastewater and hospital effluents water respectively. The excess quantity of bicarbonates in treated domestic wastewater as curing water results a decrease in compressive strength of concrete specimens. Appearance of first crack was also affected significantly by using wastewater and hospital effluents water as curing water; 7.5 kN, 6.5 kN and 6 kN were the first crack loads of normal strength concrete panels cured with fresh water, wastewater and hospital effluents water, and 11 kN, 10 kN and 7.5 kN were the first crack loads of modified reactive powder concrete cured with fresh water, wastewater and hospital effluents water.

scholarly journals Mechanical Testing of Composite Steel and Reactive Powder Concrete Structural Element

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3954
Author(s):  
Jan Bujnak ◽  
Peter Michalek ◽  
Frantisek Bahleda ◽  
Stefania Grzeszczyk ◽  
Aneta Matuszek-Chmurowska ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Composite Structures ◽  
Numerical Models ◽  
Concrete Slab ◽  
Initial Study ◽  
Cementitious Materials ◽  
Mechanical Tests ◽  
Reactive Powder Concrete ◽  
Structural Element ◽  
Reactive Powder

Reactive powder concrete (RPC), typically with higher compressive strength, is particularly attractive to structural engineers to apply them in infrastructures for enhancing their resistance under severe environments and loads. The main objective of the initial study presented in the paper was to investigate the behavior of two types of these new cementitious materials differing in the nature of microfibers. The RPC mixes were reinforced with steel and then with basalt microfibers. To evaluate the structural performance of developed unconventional materials, properties were investigated experimentally and compared with the control normal concrete mix. Mechanical tests indicated that dispersing fine fibers for making RPC, a mean compressive strength of 198.3 MPa and flexural strength 52.6 MPa or 23.2 MPa, respectively, were developed after 28 days of standard curing at ambient temperatures. In composite structures consisting of steel girders and a concrete slab, it is necessary to prevent the relative slip at the steel and concrete interface using shear connectors. The very high RPC strength enabled a material saving, weight-reduced application of precast construction, and particularly effective joint to steel beams. The investigation of such shear connection efficiency, in the case of the higher strength concrete deck, using standard push-out test specimens was executed. Finite element numerical models were developed. The outputs of the studies are presented in the paper.

Punching Shear Behavior of Flat Slabs Utilizing Reactive Powder Concrete with and without Flexural Reinforcement

2021 ◽  
Vol 26 (1) ◽  
pp. 04020060
Author(s):  
Mohammed M. Kadhum ◽  
Salah M. Harbi ◽  
Shahad S. Khamees ◽  
Mustafa S. Abdulraheem ◽  
Ehsan Noroozinejad Farsangi
Keyword(s):  
Shear Behavior ◽  
Punching Shear ◽  
Reactive Powder Concrete ◽  
Flat Slabs ◽  
Flexural Reinforcement ◽  
Reactive Powder

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.

scholarly journals Performance of Self-Compacted Reactive Powder Concrete Slab Under Harmonic Dynamic Loading

2019 ◽  
Vol 26 (1) ◽  
pp. 89-99
Author(s):  
Mohammad Makki Abbass Bilal ◽  
Mohamad Adnan Mohamad
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Loading ◽  
Static Loading ◽  
Concrete Slab ◽  
Reactive Powder Concrete ◽  
Concrete Slabs ◽  
Dynamic Resistance ◽  
Structural Element ◽  
Reinforced Concrete Slabs ◽  
Reactive Powder

Many types of loading the structure must sustain in addition to dead and live loads according to the function of structural element type that must be taken in analysis.  Dynamic resistance to loading of reinforced concrete slabs using self-compact reactive powder concrete, with different boundary conditions at the sides in addition of static loading was studied. The reinforced concrete slabs were designed under static load according to ACI-318R-2014 and then the adequacy was checked under harmonic dynamic loading. The static loading consists of dead load and residential live load considering according to ASCE-07-2010. Modeling analysis was performed to determine the eigenvalues and eigenvectors values and then frequency response analyses of the slab by finite elements method that adopted for analysis. The results indicated that in case of self-compacted reactive powder concrete rather than normal concrete gave deflection less and also there was a different result of deflection according the type of slab boundary condition supports.

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

2019 ◽  
Vol 5 (3) ◽  
pp. 528 ◽  
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.

scholarly journals Strengthening of Reinforced Concrete Slab-Column Connections with Carbon Fiber Reinforced Polymer Laminates

2019 ◽  
Vol 10 (1) ◽  
pp. 265 ◽  
Author(s):  
Cheng-Chih Chen ◽  
Shun-Long Chen
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Concrete Slab ◽  
Fiber Reinforced Polymer ◽  
Punching Shear ◽  
Carbon Fiber Reinforced Polymer ◽  
Cfrp Laminates ◽  
Reinforced Polymer

This study presents the structural behavior and punching shear strength of the concrete slab-column connections strengthened with carbon fiber reinforced polymer (CFRP) laminates. The variables considered for the twelve specimens included the compressive strength of the concrete, the ratio of the tensile steel reinforcement, and the amount of the CFRP laminates. Square concrete slabs were simply supported along four edges. During the test, monotonically concentrated load was applied to the stub column located at the center of the slab. The punching shear strength, stiffness, and mode of failure were investigated. Test results demonstrated that increasing the compressive strength of concrete, ratio of the steel reinforcement, and amount of the CFRP laminates led to an increase in the punching shear strength of the slabs. Moreover, the CFRP laminates were effective in appreciably increasing the punching shear strength of the slab-column connections. An analytical approach was conducted to calculate the punching shear strength of the slab-column connections strengthened with CFRP laminates. Based on the theory of reinforced concrete members, the application of the CFRP laminates increased the flexural strength of the slab and resulted in an increase of the effective depth of the slab section. Consequently, the punching shear strength was increased. The results of the analytical calculation revealed that the analytical work accurately predicted the experimental punching shear strength.

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