AS 5228.1:2021 pdf Cranes — Design calculation for rail wheels and associated trolley track supporting structure

AS 5228.1:2021 pdf Cranes — Design calculation for rail wheels and associated trolley track supporting structure
1  Scope
This part of ISO 16881 gives the requirements for the selection of the size for iron or steel wheels and presents the formulae for the local stresses in crane structures due to the effects of the wheel loads.
2  Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 4301-1, Cranes and lifting appliances — Classification — Part 1: General
ISO 4306-1, Cranes — Vocabulary — Part 1: General
ISO 8686-1, Cranes — Design principles for loads and load combinations — Part 1: General
ISO 8686-2, Cranes — Design principles for loads and load combinations — Part 2: Mobile cranes
ISO 8686-3, Cranes — Design principles for loads and load combinations — Part 3: Tower cranes
ISO 8686-4, Cranes — Design principles for loads and load combinations — Part 4: Jib cranes
ISO 8686-5, Cranes — Design principles for loads and load combinations — Part 5: Overhead travelling and portal bridge cranes
3  Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4306-1 apply.
4  Requirements
4.1  Selection of rail wheels
4.1.1  Rail wheel size
To determine the size of a rail wheel, the following checks shall be made:
a) verify that the wheel is capable of withstanding the maximum load to which it will be subjected;
b) verify that the wheel will allow the appliance to perform its normal duty without abnormal wear.
These verifications are made by means of the following two equations:
The mean wheel load takes into account variations of the wheel loading, including, where applicable,
positional changes of the handled load in relation to the supporting wheels during a working cycle.
Equation (3) gives an approximate value of the resultant cubic mean loading.When the work process is well known, the cubic mean load can be calculated more accurately using the wheel loads resulting from the actual positions of the handled load. In this calculation, the maximum
lifted load shall be used, coefficient c 2 taking into account the variation of the load.
4.1.2  Determining the mean load
In order to determine the mean loads, the procedure is to consider the maximum and minimum loads withstood by the wheel in the loading cases considered, i.e. with the appliance in normal duty but omitting the dynamic coefficients ϕ when determining P mean . The values of P mean are determined by the Equation (3) in the load combinations A and B.
4.2  Determination of the class of mechanism of the travel wheel
The determination of the mechanism class (according to ISO 4301-1) of the rail wheel is made in general terms as follows.
a) The number of working cycles, C, is taken as the specified value or the upper limit of the
given U-class.
b) The average displacement of the travel motion, x m , is specified according to intended use.
c) The wheel load spectrum class number, L i , shall be taken as specified or to be calculated from a
given spectrum or description of work cycles.
d) Total travel distance is L = 2Cx m .
e) Running time T = L/v t , where v t is the normal travel speed of the motion (usually, the
maximum speed).
f) Operation time class number is calculated as Tj = 1 + Int [log (T/200,01 h)/log (2)].
4.3  Determination of local stresses due to wheel loads
The local stresses due to the wheel forces of a crab or a crane may be determined according to Annexes A and B. When the permissible stress method is used, the local stresses according to Annexes A and B, combined with the global stresses due to the rated loads, shall not exceed the permissible stresses. When the limit state method is used, the local stresses shall be calculated with the loads multiplied by the relevant partial load factors, γ p . These stresses, combined with the global stresses, shall not exceed the yield stress divided by the material factor, γ m . Factors γ p and γ m shall be taken according to the relevant part(s) of ISO 8686.