loading for helipad on building

huangyhg

loading for helipad on building
does anyone know anything regarding this or any references which can guide me as to what i should anticipate for loading from a helipad on a building. i know i should account for the weight of the helicopter, but also i imagine there should be both upward and downward wind forces plus some additional dynamic loading from landing... including possible "rough" landings.
i'm hoping theres just a psf value for both downforce and uplift...
thanks!
tyler

well, a quick yahoo search revealed many useful links.  you should try that.
here are a few:
thanks! the 5390-2b.pdf is really useful!
do a google search on this forum and you will find this question has been posted previously.
in the third link on page 12 i noticed that in the interior circle of the landing pad the weight limit of the pad structure is to be posted.  to me that implies that the design load should be the weight of the choopper that could be expected to land there.  that will take some coordination with the client.
in addition, i would not use less than 25% impact and 10% lateral load during landing - similar to crane loads.
mike mccann
mmc engineering
didn't even know you could do that... i'll be using that more in the future instead of just posting first. sorry bout that!
so basically what i am doing is i have this existing building that was grossly overdesigned in anticipation of heavy mechanical loading and roof garden areas that were never placed and now they are considering possibly placing a helipad instead...
they want to know if its possible to do without any structural changes.  i don't think it's going to fly-no pun intended , but i thought i'd take a look into it.
the existing structure might be able to support the static loads, but i'm really more concerned about deflection problems and those pesky impact and dynamic loads...
thanks!
tyler
to avoid the impact loads, just don't allow the chopper to set down...
mike mccann
mmc engineering
the total load will remain constant with the concentrated load able to load any fraction of the pad.  helicopters are usually relatively light, (less than 15 kips for the big single rotor ones).
we did one similar to yours about two years ago. we built a steel and aluminum frame on top of an existing old steel framed building. we accounted for 1.5 times the weight of the helicopter applied as point load, line load and as a pressure. remember, the wind pressure generated at landing and take-off is only slightly greater than that needed to counteract the weight of the helicopter.