STEELWORK - Conveyors, Handling and Stacking Plants.

Many industrial processes need bulk or continuous handling of materials with a typical sequence as follows:

(1) loading from bulk delivery or direct from mining or quarrying work
(2) transportation from bulk loading area to short-term storage  (stacking or holding areas)
(3) reclaim from short-term storage and transport to process plant.

Structural steelwork for the industrial plant which is utilized in these operations is effectively part of a piece of working machinery (Fig. 3.3). Design and construction standards must recognize the dynamic nature of the loadings and particularly must cater for out-of-balance running, overload conditions and plant fault or machinery failure conditions, any of which can cause stresses and deflections significantly higher than those resulting from normal operation. Most designers would adopt slightly lower factors of safety on loading for these conditions, but decisions need to be based on engineering judgement as to the relative frequency and duration of these types of loadings. The plant designer may well be unaware  that such design decisions can be made for the steelwork and frequently will provide single maximum loading parameters that could incorporate a combination of all such possible events rather than a separate tabulation; the structural steelwork designer who takes the trouble to understand the operation of the plant can therefore ask for the appropriate information and use it to the best advantage.

Typical details of conveyor support
Fig. 3.3 Typical details of conveyor support

A further feature of this type of steelwork is the requirement  for frequent  relocation of the loading area and hence the transportation equipment. Practical experience suggests that precise advance planning for specific future relocation is rarely feasible, so attention should be directed to both design and detailing so that future moves can cause the least disruption.

Foundation levels can be set at constant heights; or, if variations have to occur, then modular steps above or below a standard height should be adopted.The route should utilize standard plan angles between straight sections, and uniform vertical sloping sections between horizontal runs. Common base plate details and foundation bolt details can be utilized, even where this may be uneconomic for the initial layout installation. Some consideration should be given to allowing the supporting structure to be broken down into conveniently handled sections  rather than into individual elements; the break-down joints can be permanently identified, for example, by painting in different colours.

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