Total Lateral Building Drift
Total Lateral Building Drift
(OP)
I have a concentrically braced frame, steel, stair tower, with approximate plan dimensions of 24'x9' and an approximate height of 50'. This is an industrial application, where the tower is being used to access a bridge between two tanks for general maintenance. What is an appropriate lateral drift for the total structure (i.e. not story drift or inter-story drift as I wouldn't think those are really applicable).
H/200? 300? 400? 500? 600? Is there really a limit at all since there will be no cladding on this?
Thanks!
H/200? 300? 400? 500? 600? Is there really a limit at all since there will be no cladding on this?
Thanks!






RE: Total Lateral Building Drift
RE: Total Lateral Building Drift
I've seen code stipulations of H/100 to H/600 for story and inter-story and H/400 to H/600 for cladding and materials. But haven't been able to find anything for human perception really.
RE: Total Lateral Building Drift
RE: Total Lateral Building Drift
RE: Total Lateral Building Drift
The cost/benefit has to be looked at. If it's a major concern of the customer, then I would use H/600. The wind speed you use is also a factor. An exterior tower of that type won't be used during a code-maximum speed of 120 mph. ASCE 7 commentary discusses this.
I would approach this from a different way. Set the max drift at 3/8" at a speed of 50 mph, then figure the structure from that. Nobody should be up there if the wind speed is greater than that. I would also research OSHA to see if they have any restrictions on working on heights at high winds.