Design
D - 30
The short term allowable pull out load of a bolt is obtained
from the following formula. However, if the shear stress in
the bolt exceeds 44.1N/mm
2
(for SS400), bolt strength
verification must be carried out, and verification that the
allowable tensile stresses are not exceeded must also be
carried out.
Ta=6πL
2 .
p ...(a)
Here,
Ta : Foundation bolt allowable short term pull out load (N)
L : Embedded length of foundation bolt (mm)
However, 60 L 300
p : Correction factor for concrete design strength
FC : Concrete design characteristic strength (N/mm
2
)
(Normally 17.6N/mm
2
is used.)
For bolts positioned near the corner or edge of the
foundation, if the distance from the center of the bolt to the
edge is C L, then the bolt allowable short term pull out load
is given by either formula (b) or (c) below.
1) For L C+h
Ta=6π
.
C2
.
p ...(b)
2) For L>C+h
Ta=6π
.
(L
.
h)2
.
p ...(c)
Here,
C : Distance from the edge of the foundation to the center of
the bolt (mm)
However,
L C 4d and
h : Foundation height (mm)
Notes‚
1.It is desirable that L 6d. (d: Foundation bolt nominal
diameter)
2.In the above diagram is 4.5d for a JIS bolt.
3.If type 1 or type 2 lightweight concrete is used, allow 10%
margin.
Installation location: a) Solid foundations b) Upper surface of normal floor slab c) Bottom surface of normal ceiling slab, concrete wall surface
(Notes)
1.These are short term allowable pull out loads for bolts
embedded in as shown in the diagram above.
2.The concrete design characteristic strength is taken to be
FC=17.6N/mm
2
.
3.When the dimensions differ from the above diagram, or if
the concrete design characteristic strength differs, then
the pull out load may be calculated in accordance with the
formulae for bolts on a strong foundation, on the left.
However, the allowable pull out strength of one bolt may
not exceed 11,760N.
4.It is desirable that ‚L 6d. The parts indicated by "-" in the
above table are not desirable.
5.In the above diagram is 4.5d for a JIS bolt.
6.If type 1 or type 2 lightweight concrete is used, allow 10%
margin.
Notes
1.These are long term allowable pull out loads for bolts
embedded in as shown in the diagram above.
2.The concrete design characteristic strength is taken to be
FC=17.6N/mm
2
.
3.When the dimensions differ from the above diagram, or if
the concrete design characteristic strength differs, then the
pull out load may be calculated in accordance with the
formulae for bolts on a strong foundation, on the left, and
divide the result by 1.5 to obtain the allowable pull out
load. However, for foundation bolts provided in the bottom
surface of ceiling slabs and on the surface of the concrete
walls, the allowable pull out load may not exceed 7,840N
per bolt.
4.It is desirable that ‚L 6d. The parts indicated by "-" in the
above table are not desirable.
5.In the above diagram is 4.5d for a JIS bolt.
6.It is necessary to investigate the short term pull out
strength of normal supports due to an earthquake
provided in the bottom surface of ceiling slabs and on
concrete walls for supporting heavy objects. For this short
term pull out load, see Item b) short term pull out loads.
7.If type 1 or type 2 lightweight concrete is used, allow 10%
margin.
P= Min , 0.49 +
6
1
C 50mm
2
1
30
Fc
100
Fc
(1)Allowable pull out load of embedded J type and JA type bolts
Short term pull out load (N) Long term allowable pull out load (N)
Mortar finish
7. Center of gravity position and earthquake resistant design
To Next Page
Loading...
