Section: 11 CARGO OPERATIONS - Univan

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Univan Ship Management Limited Issue 1 REV 0 Page 5/7 FLEET OPERATION MANUAL Date 01.01.2005 CARGO PLANNING 11.3.5 Consideration of Uniform and axle load in Cargo planning Copyrights: Univan Ship Management Limited, Hong Kong. All rights reserved Any unauthorized reproduction of this manual, in any form is prohibited SECTION 11.3 One of the important factors while planning loading of a Pure Car Carrier is to check whether uniform load and axle loads of the cargo being loaded are within permissible limits. This is very important when you are loading loaded trucks or Mafi-trailers. Well some time you may load the loaded trucks particularly to East African ports and the correct weight of the loaded truck is not known. Please insist on the local agent to give the correct weights of the cargo in loaded trucks. So that vessels stability and uniform and axle loads for the particular cargo can accurately be calculated. 11.3.5.1 Uniform Load The uniform load or spread load may be defined as the load exerted by the cargo on the deck plating per square metre. The permissible uniform load is the load which the particular deck can be able to withstand per square metre without any possibility of danger. Need less to say for any cargo loaded the uniform load should be always less than maximum permissible uniform load. Generally the decks of a Ro-Ro Cargo Carriers are designed for very low permissible uniform load. The range vary from 0.2 MT/ M 2 to 1 MT/ M 2. . Example No: 1 Let us assume you are loading a mafi trailer of dimension 60’ x 10’ the weight of the cargo with Mafi is 50 MT. If permissible uniform load of that deck is 0.7 MT/ M 2 then please check if this cargo can be loaded or not Solution: The area occupied by the Mafi in Square feet = 60 x 10 = 600 Sft The area occupied in Square metres = 600 x .3048 x .3048 = 55.74 Sm The allowable load can be taken up by the deck plating = 55.74 x 0.7 =39.01 MT But the weight of the cargo is 50 Mt, which is much more than allowable. Hence this cargo can not be loaded. 11.3.5.2 Axle load The axle load is the load on the axle of the vehicle. It is also called shaft load. The permissible axle load is the maximum allowable load on the axle of the vehicle loaded on that deck. As eventually the load on the axle is being transmitted on to the deck underneath the tires. Axle load / 2W: Means the load on the axle basis 2 wheels per axle. Axle load / 4W: Means the load on the axle basis 4 wheels per axle. When ever the axle load is given basis 2W(cars), The total load of the vehicle is assumed to be equally shared by both front and rear wheels. And when it is given on the basis 4W (Trucks), the axle weight is shared in such a way that 4 rear wheels will take up complete load + additionally 60% of the axle load will be taken up by the front wheels.
Univan Ship Management Limited Issue 1 REV 0 Page 6/7 FLEET OPERATION MANUAL Date 01.01.2005 CARGO PLANNING Case: 1 2MT/2W 1MT Front wheels 1 MT Rear wheels Case: 2 2MT/4W 1MT Front wheels 1MT Rear wheels Case: 3 10MT/4W 6 MT Front wheels 10 MT Copyrights: Univan Ship Management Limited, Hong Kong. All rights reserved Any unauthorized reproduction of this manual, in any form is prohibited Rear wheels Case: 3 10MT/4W 6 MT Front wheels 10 MT 10 MT Rear wheels Picture No: 10, Axle load distribution Let us take a few examples to grasp the concept completely. SECTION 11.3 Total = 1 + 1= 2 MT Total = 1+ 1 = 2 MT Total = 10+ 6 = 16MT Total = 10+10+ 6 = 26MT Example: 2 Let us assume the maximum allowable axle load for a deck is 7.5/2W MT. We are loading a truck of 18 MT weight and is having 6 wheels. Please advise if this truck can be loaded or not. Solution: Now since the truck is 6 wheels and this means the 2 front wheels and 4 rear wheels. So the total axle load which is possible = 7.5 + 7.5 + 60% of 7.5 = 15 + 4.5 = 19.5 MT Which is more than the total weight of the truck, hence this truck may be loaded.
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Section: 11 CARGO OPERATIONS - Univan

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