AS 5228.1 pdf download

AS 5228.1 pdf download.Cranes — Design calculation for rail wheels and associated trolley track supporting structure
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.4.1.3  Determining the useful rail width b For rails having a flat or slightly convex bearing surface, of total width, l, with rounded corners of radius, r, at each side (see Figure 1), the useful width, b, shall be calculated using Equation (4):For rails or wheels with a slightly convex bearing surface, the limiting pressure P L may be increased by 10 %. This allows for the improved contact of a rail to the rolling motion of the wheel. In the case of a flat, tapered or convex wheel running on the bottom flange of a beam, the useful width is calculated by Equation (5):where the wheel tread of width, w, and the corner radius r are to be taken according to Figure 2. The wheel diameter, D, shall be taken as the mean diameter on the projected width (w − r).The qualities of metal correspond to cast, forged or rolled steels, and spheroidal graphite cast iron. The hardening of the wheel tread at the depth of 0,01D may be taken into account when selecting the value of P L . In the case of rail wheels with tyres, consideration must obviously be given to the quality of the tyre, which shall be sufficiently thick not to roll itself out. 4.1.5  Determining coefficient c 1 The values of c 1 depend on the speed of rotation of the wheel and are given in Table 2.The formulae apply only to wheels whose diameters do not exceed 1,25 m. For larger diameters, experience shows that the permissible pressures between the rail and the wheel must be lowered. The use of wheels of greater diameter is not recommended. NOTE  The wheel selection method presented here is based on FEM 1.001-1988, Booklet 4, as revised in Booklet 9 in 1998. This method is based on the group classification of mechanisms (classes M1 to M8) that is equal to the classification of ISO 4301-1.
When determining the reference stresses according to ISO 8686-1 to ISO 8686-5 and in the fatigue stress verification, the local stresses shall be superimposed on the global stresses. Attention must be paid to the plus and minus signs. In the load combinations A, B and C (see Table 1) and in the fatigue strength verification (load combinations A), the local stresses in the plates and full penetration welds shall be multiplied by 0,75 before superimposing with the global stresses. In fatigue analysis, when coefficient 0,75 is used, the combined stresses shall be compared to the tension fatigue strength of the weld joint or the detail. The local stresses can be reduced by factor 0,75 because of the extra plastic bending capacity of the flange plate or extra plastic tension capacity of the web. In fatigue analysis the effect of the local stress can be reduced, because the fatigue strength in bending of a plate is typically 30 % to 60 % higher than in tension, for the same joint or detail. If the wheel loads, F, are not symmetrical, the local stresses are calculated with the maximum wheel load and the relevant distance, i. In addition to these flange bending stresses and the main stresses, torsion stresses from the resulting non-symmetrical load application point must be calculated in the girder cross section.