Designing a boathouse
Designing a boathouse
(OP)
So I'm designing a boathouse that has 8" diameter wood piles. The piles will be driven in at a 6 ton capacity. Assuming a fixed base, the piles will be very tall to support an upper story deck with a boat slip below. I'm concerned about the sway and want to check for the need for bracing. I can calculate the wind load easily but what load should I use for the impact from a boat on the side of one of the piles. I don't want a light bump to cause the entire structure to shake but I don't know what impact force to assume.






RE: Designing a boathouse
Ps = 220DWT^2(V/27), where
Ps = equivalent static force in kips
DWT = deadweight tonnage of the vessel
V= impact speed in ft/s
Wouldn't you be better off with a fender system to absorb the impact energy rather than putting the force into your piles?
RE: Designing a boathouse
P = 8.15 (DWT)^0.5*V
Either way, if I assume a 1 ton boat hitting at 1 ft./sec I get at least 8.15 kips of force. Seems pretty high to me.
www.idecharlotte.com
RE: Designing a boathouse
The piles are only partially fixed some distance below the mud line, and you've given no dimesnions, then canti. up to the water elev. which may vary; there may be some framing support or bracing at approx. this elev., at least in one wall line direction; then there may be some support or bracing under the upper deck depending upon how you frame it, in two directions. Then you train your skipper to kiss the dock, and live with some amount of movement up on the roof deck. Sorry, no answers, just some food for thought.
RE: Designing a boathouse
Blodgetts "Solutions to Design of Weldments" (a great little book)
has impact examples.
Kinetic energy=Potential energy
Kinetic energy=1/2mv^2
Potntial energy=1/2F(delta L), k=F/(delta L)
=F^2/2k
1/2mv^2=F^2/2k, solve for F, k=stiffeness of pile, fixed at base
and cantilevered.
RE: Designing a boathouse
Plus that stuff dhengr said too :)