Moment and shear transfer between columns and concrete slabs

1990 ◽  
Vol 17 (4) ◽  
pp. 621-628
Author(s):  
Amin Ghali ◽  
Adel A. Elgabry
Keyword(s):  
Shear Strength ◽  
Structural Design ◽  
American Concrete Institute ◽  
Punching Shear ◽  
Vertical Shear ◽  
Concrete Slabs ◽  
Finite Element Analyses ◽  
Shear Transfer ◽  
Flat Slabs ◽  
Punching Failure

Gravity and horizontal forces cause the transfer of vertical shear and moments between concrete flat slabs and their supporting columns. These forces can cause punching failure. Design equations for safety against punching given in the Canadian Standards Association and the American Concrete Institute codes are critically reviewed. It is shown that the equations give in some cases incorrect stresses which do not satisfy equilibrium. A modification is suggested which makes the equations applicable to all cases. The paper also discusses the codes' approach of sharing the resistance to transferred moment between resistances by flexure and by eccentricity of shear, using the coefficient γv. Comparisons are made with the result of finite element analyses. It is concluded that the code equations, with the suggested modification, are adequate, provided that appropriate values are used for the coefficient γv. Key words: columns, connections, flat concrete plates, moments, punching shear, reinforced concrete, shear strength, slabs, structural design.

Critical shear crack theory-based punching shear model for FRP-reinforced concrete slabs

2020 ◽  
pp. 136943322097814
Author(s):  
Xing-lang Fan ◽  
Sheng-jie Gu ◽  
Xi Wu ◽  
Jia-fei Jiang
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Shear Crack ◽  
Concrete Strength ◽  
Weight Ratio ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Crack Theory ◽  
Reinforced Concrete Slabs ◽  
Rc Slabs

Owing to their high strength-to-weight ratio, superior corrosion resistance, and convenience in manufacture, fiber-reinforced polymer (FRP) bars can be used as a good alternative to steel bars to solve the durability issue in reinforced concrete (RC) structures, especially for seawater sea-sand concrete. In this paper, a theoretical model for predicting the punching shear strength of FRP-RC slabs is developed. In this model, the punching shear strength is determined by the intersection of capacity and demanding curve of FRP-RC slabs. The capacity curve is employed based on critical shear crack theory, while the demand curve is derived with the help of a simplified tri-linear moment-curvature relationship. After the validity of the proposed model is verified with experimental data collected from the literature, the effects of concrete strength, loading area, FRP reinforcement ratio, and effective depth of concrete slabs are evaluated quantitatively.

Punching shear strength of reinforced concrete slabs with plastic void formers

2017 ◽  
Vol 145 ◽  
pp. 518-527 ◽  
Author(s):  
Juozas Valivonis ◽  
Tomas Skuturna ◽  
Mykolas Daugevičius ◽  
Arnoldas Šneideris
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Reinforced Concrete Slabs

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.

Punching Shear Strength Model for Reinforced Concrete Flat Slabs with Openings

2021 ◽  
Vol 147 (7) ◽  
Author(s):  
Marília G. Marques ◽  
Elyson A. P. Liberati ◽  
Ronaldo B. Gomes ◽  
Alessandra L. Carvalho ◽  
Leandro M. Trautwein
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Punching Shear ◽  
Strength Model ◽  
Flat Slabs

scholarly journals Evaluation of punching shear strength of flat slabs supported on rectangular columns

2018 ◽  
Vol 33 ◽  
pp. 02007 ◽  
Author(s):  
Valery Filatov
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Slab ◽  
Structural Parameters ◽  
Experimental Studies ◽  
Punching Shear ◽  
Design Solution ◽  
Concrete Slabs ◽  
Reinforced Concrete Slabs ◽  
Rectangular Columns

The article presents the methodology and results of an analytical study of structural parameters influence on the value of punching force for the joint of columns and flat reinforced concrete slab. This design solution is typical for monolithic reinforced concrete girderless frames, which have a wide application in the construction of high-rise buildings. As the results of earlier studies show the punching shear strength of slabs at rectangular columns can be lower than at square columns with a similar length of the control perimeter. The influence of two structural parameters on the punching strength of the plate is investigated - the ratio of the side of the column cross-section to the effective depth of slab C/d and the ratio of the sides of the rectangular column Cmax/Cmin. According to the results of the study, graphs of reduction the control perimeter depending on the structural parameters are presented for columns square and rectangular cross-sections. Comparison of results obtained by proposed approach and MC2010 simplified method are shown, that proposed approach gives a more conservative estimate of the influence of the structural parameters. A significant influence of the considered structural parameters on punching shear strength of reinforced concrete slabs is confirmed by the results of experimental studies. The results of the study confirm the necessity of taking into account the considered structural parameters when calculating the punching shear strength of flat reinforced concrete slabs and further development of code design methods.

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