Reinforced concrete (RC) slabs are characterized by reduced construction time, versatility, and easier space partitioning. Their structural behavior is not straightforward and, specifically, punching shear strength is a current research topic. In this study an experimental database of 113 RC slabs without shear reinforcement under punching loads was compiled using data available in the literature. A sensitivity analysis of the parameters involved in the punching shear strength assessment was conducted, which highlighted the importance of the flexural reinforcement that are not typically considered for punching shear strength. After a discussion of the current international standards, a new proposed model for punching shear strength and rotation of RC slabs without shear reinforcement was discussed. It was based on a simplified load-rotation curve and new failure criteria that takes into account the flexural reinforcement effects. This experimental database was used to validate the approaches of the current international standards as well as the new proposed model. The latter proved to be a potentially useful design tool.
. [J]. Frontiers of Structural and Civil Engineering, 2020, 14(5): 1196-1214.
Luisa PANI, Flavio STOCHINO. Punching of reinforced concrete slab without shear reinforcement: Standard models and new proposal. Front. Struct. Civ. Eng., 2020, 14(5): 1196-1214.
High strength concrete; proposal for a new failure criterion.
I
[11]
2005
10
Low flexural reinforcement ratio r, variations of slabs dimensions and maximum aggregate size. Crack development, comparison between the ACI 318, EC2, and CSCT models.
D
[12]
2000
6
Scale effect; comparison between ACI 318 and Canadian standard model.
Recycled concrete; concrete compressive strength fc.
I
[15]
2012
6
Recycled concrete; concrete compressive strength fc.
I
[16]
2013
12
Flexural reinforcement ratio r.
I
[17]
2012
5
Experimental test for validation of Muttoni model.
D
[18]
2015
8
Recycled concrete; concrete compressive strength fc.
I
[19]
2015
4
High strength concrete; concrete compressive strength fc; flexural reinforcement ratio r, comparison between ACI 318, EC2, and MC10 models.
I
[20]
1996
18
High strength concrete; concrete compressive strength fc; flexural reinforcement ratio r; comparison between ACI 318, EC2, MC90, and BS8110.
D
Tab.1
symbol
parameters
n
xmin
xmax
h
thickness (mm)
113
50
550
148
h/L
thickness/span
113
0.05
0.31
0.09
r
flexural reinforcement ratio
113
0.15%
3.7%
1.1%
r′/r
top/bottom reinforcement ratio
56
0.11
1
0.53
a/L
load surface size/span
113
0.05
0.28
0.13
dg
maximum aggregate size (mm)
113
4.0
38.1
18.3
dg/h
maximum aggregate size/thickness
113
0.02
0.4
0.16
fc
concrete compressive cylindrical strength (MPa)
113
12.8
130
50
fy
steel yielding strength (MPa)
113
303
709
504
Tab.2
Fig.5
Fig.6
Fig.7
Fig.8
Fig.9
Fig.10
Fig.11
Fig.12
Fig.13
Fig.14
Fig.15
Fig.16
Fig.17
item
model
average
min.
max.
CoV
Vpunch,exp/Vpunch,theo
MC10
1.27
0.78
1.77
0.16
ACI 318
1.27
0.59
2.00
0.26
EC2
1.17
0.74
1.71
0.18
ypunch,exp/ypunch,theo
MC10
1.27
0.41
6.81
0.64
Tab.3
Fig.18
Fig.19
Fig.20
Fig.21
Fig.22
item
model
average
min.
max.
CoV
Vpunch,exp/Vpunch,theo
MC10
1.27
0.78
1.77
0.16
ACI 318
1.27
0.59
2.00
0.26
EC2
1.17
0.74
1.71
0.18
new proposal
1.06
0.66
1.46
0.16
new proposal with dg
1.10
0.62
1.64
0.21
ypunch,exp/ypunch,theo
MC10
1.27
0.41
6.81
0.64
new proposal
1.29
0.38
8.68
0.87
new proposal with dg
1.27
0.48
7.82
0.75
Tab.4
Fig.23
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