Belt Conveyor Truss Design
Belt Conveyor Truss Design
(OP)
I had this post in the materials handling forum but did not get any response so I thought I would try it here. I have been asked to design some standard truss parallel chord frames, with allowable spans for particular belt widths. The trusses are to carry limestone and coal, and are to be designed to support all the bells and whistles, (walkways, hoods, idlers, pull-stops, and electrical). My question is as follows. Normally I have engineered conveyors for a specific application. This means that the TPH and the pulley resultant loads are known. For the standard truss designs these properties are not known. I have found a previous engineers calcs for similar work and all that he did was design the truss for a uniform moment of 1/8 wl^2, due to the distributed load. This was before computers were widly used in design offices. While I would agree that would give you the worst case chord force, I am not sure that the loadings are really ideal. He used a surcharged belt with 20psf on the walkway, but of course had no way to account for the compression in the truss due to the conveyor drives. Is this a good way to design the truss, since the likelyhood of a surcharged belt and a 20psf walkway load all happening at once is somewhat unlikely? If not what would you recommend? Thanks in advance for your help.






RE: Belt Conveyor Truss Design
RE: Belt Conveyor Truss Design
The rock will be minus 2", thus no impact loading for the rock is required, assuming that this is a typical span, and not being loaded somewhere in the span. Any impacts due to startup or variances in the drive would again be unknown.
RE: Belt Conveyor Truss Design
Also the 20psf live load for the walkway sounds light by today's standards, you will probably find numbers more like 60 psf. Sometimes these walkways are used for more than foot traffic - the conveyor breaks down, mechanics have to haul heavy tools & repair parts over the walkway.
RE: Belt Conveyor Truss Design
RE: Belt Conveyor Truss Design
RE: Belt Conveyor Truss Design
Therefore the intermediate trusses are typically designed for a combination of gravity loads (self weight of steelwork, idlers, belt, piping; cabling; normal material load; flooded material load; walkway load) and wind loads.
An exception to this is a Stockpile Feed Conveyor where there is no head-end structure (final truss span is cantilevered) and the belt tensions must be taken through the trusses to the take-up tower.
I expect that the standard trusses you are designing would not see belt tensions at all.
RE: Belt Conveyor Truss Design