29416 Graepel TH engl. neu:Inhalt - Friedrich Graepel AG

Load types
Preliminary remarks to the table
on the following pages
The metal profile gratings are dimensioned for the
elastic material region. In this, either dimensions
are taken considering the permissible stress of the
material or considering the permissible deflection.
The table values always consider the least
advantageous value.
The permissible deflection of the “metalprofile
grating” beam is L/200, where L is the support
width.
In the case that greater deflections are permitted,
then the deflection is to be calculated with the aid
of the areal moment of inertia of the individual
grating type according to the normal structural
calculations.
For gratings lying next to each other, the deflection
of the loaded individual gratings must be bolted
together. A bolt spacing of approximately 500 mm
recommended.
The following loads can occur.
a) vertikal on the surface of the grating effective
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uniformly distributed load in kN/m
b) effective vertical concentrated load in kN
effective over the whole grating width distributed
on a surface area of B x 0,2 m. Here the concentrated
load is to be placed in the most disadvantageous
position.
c) effective vertical lump load in kN acting on a
surface area of a 1x a 2. The sizes of the loads and
the long effective surface can be determined from
DIN 1055 sheet 3 or DIN 1072.
Uniformly distributed load
Only the unperforated area of the two sides is taken in
account. In the static cross section values for the long direction
of the grating.
Concentrated load
Lump load
Determination of the permissible uniformly
distributed load
Conversation of the replacement load Fq
from the table into an uniformly distributed
load Q:
10 6 xFq
Q =
whereaby:
B x L
Q = Distributed load for a grating [in kN/m 2 ]
Fq= Replacement load from table with reference
to the support width [in kN]
B = Grating width [in mm]
L = Support length [in mm]
Calculation example: (dimensions in mm)
Material: DD 11 Material thickness: S = 2.5
Edge height: H = 40 Support length: L = 1250
Table value: Fq = 2.52 kN
Grating width B = 240 mm
10 6 x2.52
Q =
240 x 1250
= 8.40 kN/m 2
Determination of the permissible
concentrated load
The value of the permissible concentrated load
with reference to the material, material thickness,
edge height and support width can be read directly
from the tables.
This assumes that the load surface acts over the
whole grating width B then the load values of the
table “lump load” must not be exceeded. Decisive
is the lower value.
Load increases
1. When placing the grating over serveral supports
(continuous beam), the permissible loads can be
increased according to normal structural calculations.
2. If the gratings are bolted together such that the
load only acts on the middle grating, then the
permissible load values from the table can be
doubled.
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