DIY Staircases
In message , Mike )
wrote: "N. Thornton" wrote in message om... Hate to be a harbinger of doom but if your BCO asks for strength calculations it becomes a serious headache. Ours said he would so we decided to buy one from a company that will do calcs if needed. Of course then he said he didn't need them from them. Why is this a headache? Sagulator makes calculating this easy, does it not? http://www.woodbin.com/calcs/sagulator.htm For a single piece of 2x5 pine, 110" long, 450kg will produce 0.5" deflection. The stair uses 2 pieces of 2x5, so real world deflcetion for 450kg closer to 0.25". Apply a 4 ton load to the stair, evenly distributed, and total deflection now 2.25". At 100kg a piece, 4 tons would represents 40 people on the stair. And thats 40x 220lb people! I reckon that should do. (They would have to be evenly distributed to even think of getting that many on there.) For the individual treads, lets say 8" x 36" x 1.25", with 2 people standing on a tread: deflection 0.13". All these deflections are well within breaking point of softwood. Am I missing something? NT |
N. Thornton wrote:
http://www.woodbin.com/calcs/sagulator.htm FX: cacophony of mouse clicks hitting "add bookmark" ;-) |
"N. Thornton" wrote in message om... In message , Mike ) wrote: "N. Thornton" wrote in message om... Hate to be a harbinger of doom but if your BCO asks for strength calculations it becomes a serious headache. Ours said he would so we decided to buy one from a company that will do calcs if needed. Of course then he said he didn't need them from them. Why is this a headache? Sagulator makes calculating this easy, does it not? http://www.woodbin.com/calcs/sagulator.htm Great link. Any more like this ? However I think you're underestimating the deviousness of most BCOs. They aren't interested in the calculations - in fact they don't understand them if presented with them - but want an easy life by stopping all these pesky DIYers doing anything. The myths surrounding Part P, which after all is no more onerous than Parts A through whatever, are probably spread by them. |
Andy Burns wrote:
N. Thornton wrote: http://www.woodbin.com/calcs/sagulator.htm FX: cacophony of mouse clicks hitting "add bookmark" ;-) Hmm, not wanting to **** on that particular firework, but having just done a side by side calculation against Superbeam, the web site seems to get the wrong answer. I did a calculation on a "shelf" (i.e. a joist) made from "Pine, Spruce", with a distributed total load of 240kg over its 4m length (i.e. 0.6kN/m) and a size of 200x50mm. The web site calculates just under 7mm deflection. Superbeam gets approaching double that. (all the sums done on the web site seem to be embedded in a few pages of (obfuscated) javascript. If one CBA, one could extract the logic and see what it is doing). -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
All times are GMT +1. The time now is 05:08 AM. |
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 DIYbanter