450
IBRACON Structures and Materials Journal • 2013 • vol. 6 • nº 3
Numerical analysis of two pile caps with sockets embedded, subject the eccentric compression load
This shows that the resistant capacity of the block cannot be de-
termined in function of the rupture of the compressed diagonal,
but by the puncturing effect of the bottom “slab”. It is interesting to
observe that, the puncturing effect will only occur if, and only if, the
force on the column is transmitted (almost all) to the bottom “slab”
and, this will only happen if the embed length is small, not being
possible the formation of the connection (or stanchion), being the
element rupture characterized by punching shear.
Figure [26] presents bends “reaction in the most solicited pile vs.
displacement in the middle of the pile cap span” for the models
numerically analyzed.
Figure [27] shows the distribution of the main stress of compres-
sions inside one of the numerically analyzed pile caps and Figure
[28] shows the panorama of cracking of the same pile cap pre-
sented in Figure [27], referring to the last force increment.
For the pile caps models with conformation of the sockets and col-
umn walls, with performance of normal force and moment in the
pile cap, factor ℓ
emb
is the main relevant factor, followed by factor h
s
.
Table [7] shows the results of the analysis of variance of the pile
caps models with conformation of the walls of the sockets and col-
Table 6 – Analysis of variance, ANOVA, blocks with smooth conformation and action
of compressive force eccentric
Pile
caps
Measure
the sides
of the
column
(cm)
Measure
the sides
of the
piles
(cm)
h
s
(cm)
e
(cm)
h
(cm)
F
u
(kN)
A
b,est
2
(cm )
Blévot
Blévot
Num.
Num.
F / F
blévot
num
ℓ
emb
(cm)
Ɵ
(graus)
L
ℓ
80hs30NM
e
L
ℓ
80hs20NM
e
L
ℓ
80hs10NM
e
L
ℓ
60hs30NM
e
L
ℓ
60hs20NM
e
L
ℓ
60hs10NM
e
L
ℓ
50hs30NM
e
L
ℓ
50hs20NM
e
L
ℓ
50hs10NM
e
20 x 20
20 x 20
20 x 20
20 x 30
20 x 30
20 x 30
20 x 40
20 x 40
20 x 40
20 x 20
25 x 25
30 x 30
20 x 20
25 x 25
30 x 30
20 x 20
25 x 25
30 x 30
30
20
10
30
20
10
30
20
10
2,44
3,00
2,84
2,90
4,35
5,96
3,59
4,01
4,44
120
110
100
100
100
80
90
80
70
3663
3415
3128
3128
2800
2428
2800
2428
2016
323,6
487,8
673
299,1
441,9
592,8
282,8
411,7
355,9
3663
3415
3128
3128
2800
2428
2800
2428
2016
269,6
365,8
639,4
299,1
397,7
497,9
207,3
288,2
177,9
1,27
1,17
1,28
1,18
1,22
1,91
1,24
1,96
3,16
80
80
80
60
60
60
50
50
50
54,0
51,3
48,4
48,4
45,0
41,2
45,0
41,2
36,9
Note: Num., value obtained by numerical simulation Blévot, value calculated using the criteria Blévot & Fremy [4] F , Rupture force applied in
u
the column, and eccentricity of the normal force, A , area of the strut near the column.
b,est
Figure 26 – Curve Force vs. displacement
in the middle of the span,
pile caps with smooth conformation,
normal force and moment
Figura 27 – Principal stress compression, pile cap
with smooth conformation, normal force
and moment
Lℓe60hs20NM
1...,95,96,97,98,99,100,101,102,103,104 106,107,108,109,110,111,112,113,114,115,...167