Posted By Tony McIntosh Slightly puzzled, so if anyone knows the answer it would be greatly appreciated. It relates to a bridge plate we use. Assuming no distribution of load over the bridge plate, the safe working load is 4.91 tonnes. If the bridge plate is used to bridge a narrow gap, the area that actually has to take load is reduced, and therefore its load capacity is drastically increased. For use in our application (FLT driving over 22 inch gap) we have had an engineering company calculate the load limit to be 0.95 tonnes per square inch. Our FLTs exert 0.64 tonnes per square inch. So in the plates current application we have had it confirmed that we are using the plate within its capacity. However, we now have to display the rated capacity on the plate itself – which is where I’m now stumped. Can I put the capacity of it for our application?? Or do I have to put the plates capacity assuming no load, which is 4.91 tonnes? Our FLT fully laden comes in at 12.5 tonnes. If anything needs clarifying please ask. Thanks for you help

Posted By Richard Altoft Tony, I assume this is just a flat plate acting as a bridge capable of being analysed just like a beam or joist etc. If so would it be possible to either give it a reference number and a scale of SWL agaianst gap covered within a SSOW in effect or label it with a range of SWL based on configuration (gap) as you do with a sling agaainst its angle or a crane with load/radius. With a plate there will be a minimum end length that must be in contact with solid bearing surface at each end but other than that you can calculate SWL when spanning say 500mm, SWL when spanning 1000mm, SWL when spanning 1500mm etc. Am I on the right track!!! R

Posted By Richard Altoft To be honest I don't know - what I would say however is the information must make sense to the person needing that info such as a FLT driver so per square inch is not much use. How about axle load or wheel versus unsupported span length or "gap". Clearly only the weight over the gap is relevant which is why highway bridges are signed in axle load limits not total weight of lorry. You could try an enquiry pretending to buy a plate from a manufacturer and see what they are "sold by" as regards capacity and how they are labelled. With a scaffold board, taking a simple example, their capacity is given as X if supported at Y centres. R