Recent content by Structural Eng 7

We have decided to provide WF compression struts to laterally brace the top chord at panel points and for erection and long term performance we are adding diagonal bracing between the top and bottom chord every few bays. We are also using a horizontal braced frame for lateral stability at the...

Gents, thanks for the replies. Yes this is a roof and bottom chord has bracing. Main issue we are getting kick back about is in regards to lifting the trusses into place. Mid depth bracing is my preferred system just having issues with figuring out if they can install all joists on ground and...

All, Looking for others opinions/solutions for an issue that has come through my office. We are designing 200’ long trusses with WF top and bottom chords. The issue coming up is the lateral stability of the top chord since the joists supported by the top chord bear on the top flange. Typically...

My thoughts were L/300 would suffice but wanted to check someone else's thoughts on the situation as this is my first crane structure design and it's been a 'doozy'. So essentially, if I have a 25' runway span, my deflection at the end of the runway could be 1" and the slope would still be in...

To Clarify... the 'L' I am referring to would be the crane runway span.

Hi All, I have a Crane Runway beam that is picked up at the end of the runway by a transverse beam. The transverse beam is actually cantilevered and I am wondering what the thought is on the allowable deflection of the cantilever. Does say L/600 still apply? or is there another process to go...

Well that's what I would think, but the product specs state a compressibility capacity of 1000psf, which I'm sure our floor slab does not have. Also we have seen cases where the void form has not broken down properly and heaving has occurred as a result. The specific brand of void form...

Thanks for the quick replies guys... The whole point of the decomposing is to create an air void to allow for soil expansion beneath the slab so that heaving does not occur ( it is supported on piles). We have thought about water, but are scared that if we dump too much beneath the slab, the...

Hey guys, My office has recently installed a structural slab over expansive soil using a cardboard void form. Our drawings strictly state not to place a ground poly sheet (so the cardboard will breakdown) and we didn't catch that the contractor did happen to place a ground poly sheet. The slab...