Personell Hoist Wind Design
Personell Hoist Wind Design
(OP)
I'm designing the tiebacks for a Personell Hoist on the east coast. The building is 126ft to top of roof. The top of the hoist is 145ft. I calculated the wind force using ASCE 7-02, section 6.5.13 (Open buildings and other structures). My question is: How conservative should I be? I'm getting a wind force of 29 psf +/-. I started to design for both cars to be at the top of building, one above top floor and one at the floor below it creating the worst case surface area. I used the 50 yr wind speed which induces a huge load for the tie back. Is this too conservative? I decided to multiply the wind load by .75 because of low probability of both cars being at the top of the building during this event but it is still very high. Do I assume they lower the car during the 50 yr wind? If I do then what speed should I use? I'm starting with an existing drawing that notes an "in service" wind speed of 35 mph and a "Out service" wind speed of 115 mph. I placed a note on the drawings that the cars need to be lowered to the ground when the wind velocity is greater than the "in service" speed. 35 mph creates a very small load and not conservative enough.
Thanks for you help!
Thanks for you help!






RE: Personell Hoist Wind Design
I'd say you were on the right track with the huge load on the tieback.
RE: Personell Hoist Wind Design
This is exactly what caused a window washer's platform to fall off a Chicago skyscraper a few years back - on I think a Sunday morning. Unfortunately, it "flew" all the way to an intersection crushing a car and killing 2 or 3 women.
RE: Personell Hoist Wind Design
www.anchorengineer.com