TM 5-809-1/AFM 88-3, Chap. 15
CHAPTER 3
DETERMINATION OF FLOOR SLAB REQUIREMENTS
3-1. Vehicular loads.
the drive axle of a forklift truck is normally 87 to 94
percent of the total gross weight of the loaded
The following traffic data are required to determine
vehicle.
the floor slab thickness requirements:
-- Types of vehicles
For tracked vehicles, the gross weight is evenly
-- Traffic volume by vehicle type
divided between two tracks, and the severity of the
-- Wheel loads, including the maximum
load can easily be expressed in terms of gross
single-axle and tandem-axle loading for
weight. For moving live loads, axle loading is far
trucks, forklift trucks, and tracked
more important than the number of load repetitions.
vehicles
Full-scale experiments have shown that changes as
-- The average daily volume of traffic
little as 10 percent in the magnitude of axle loading
(ADV) which, in turn, determines the
are equivalent to changes of 300 to 400 percent in
total traffic volume anticipated during the
the number of load repetitions.
design life of the floor slab.
For floor slabs, the magnitude of the axle load is of
3-2. Traffic distribution.
far greater importance than the gross weight. Axle
spacings generally are large enough so that there is
To aid in evaluating traffic for the purposes of floor
little or no interaction between axles. Forklift truck
slab design, typical forklift trucks have been divided
traffic is expressed in terms of maximum axle load.
into six categories as follows:
Under maximum load conditions, weight carried by
Forklift Truck
Forklift Truck
Maximum Load
Category
Maximum Axle Load, kips
Capacity, kips
I
5 to 10
2 to 4
II
10 to 15
4 to 6
III
15 to 25
6 to 10
IV
25 to 36
10 to 16
V
36 to 43
16 to 20
VI
43 to 120
20 to 52
When forklift trucks have axle loads less than 5 kips
considering each axle as one forklift truck axle of
and the stationary live loads are less than 400
approximate weight. For example, a three-axle truck
pounds per square foot, the floor slab should be
with axle loads of 6, 14, and 14 kips will be
designed in accordance with TM 5-809-2/AFM 88-
considered as three forklift truck axles, one in
3, Chap. 2. Vehicles other than forklift trucks such
Category I and two in Category II. Tracked vehicles
as conventional trucks shall be evaluated by
are categorized as follows:
Forklift
Truck
Tracked Vehicles
Category
Maximum Bross Weight, kips
I
less than 40
II
40 to 60
III
60 to 90
IV
90 to 120
Categories for tracked vehicles may be substituted for the same category for forklift trucks.
3-1
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