reinforcing open web joists
reinforcing open web joists
(OP)
This is probably too long but here goes. Some background...existing roof consisting of owsj joists spaced @5.5' spaning 42 ft. Arch needs to add 20psf DL to roof. I came up with two scenarios..1.reinforce existing owsj which is very labour intensive but cheap materials and option 2. add beams between exiting owsj, effectively reducing TA to 2.75'...very costly for materials cheaper labour. Each option turns out to be too expensive, does anybody have any other possible solutions or suggestions. There are a total of 35 beams/owsj to be considered.
thanks
thanks






RE: reinforcing open web joists
RE: reinforcing open web joists
RE: reinforcing open web joists
I think the three options presented (reinforce, add beams, add column/beam line) are your primary options short of my first sentence - why add the load?
Can the supporting beams hold the 20 psf additional load? Can the supporting columns and footings?
20 psf seems a bit much.
RE: reinforcing open web joists
Just discussed an option with a co-worker, he seems to think a plausible solution is to place a beam between every second joist. I can't seem to rationalize how this could possibly work?
RE: reinforcing open web joists
DaveAtkins
RE: reinforcing open web joists
Perhaps a different fire protection method would work better with the structural budget, which appears to be nil.
RE: reinforcing open web joists
It appears that possibly your fire protection engineer developed his 'most efficient' solution in a vacumn, without considering the impact of various options on other disciplines and parts of the building. And that this solution may not be the 'most efficient' when the total cost of the solution is calculated.
I would request that all fire protection options be explored in light of their total effect on the entire building (structure, mechanical, electrical, etc) and the various options (and associated total costs) be evaluated on that basis.
Then the client and other disciplines will have an idea of the total impact (Includings $$$'s) of each option and can make an informed decision on which way to procedd.
RE: reinforcing open web joists
RE: reinforcing open web joists
Surely this is better than trying to reinforce the structure. The current solution sounds like "let's find the heaviest way possible to achieve a fire separation and go from there." LOL, hyperbole that I learned from another esteemed eng-tips member!!
RE: reinforcing open web joists
lkjh345 stated it best! This may be the most "efficient" for the fire protection scheme but not for the overall project. The total cost of this must be taken into account for all systems! The architect needs to review other options.
RE: reinforcing open web joists
Tracy