Lateral loading for a marina dock 1

[Jc67roch]

Does anyone have a suggested lateral loading for a marina dock with slips (smaller, recreational boats - not commercial) on an inland freshwater lake? I have read numerous references that seem to get into the details of boat sizes, wind speed, and calculating wave heights. But it seems a marina structure would host a wide range of boat sizes. Is there a good general assumed pounds per linear foot lateral load on a dock from private-sized (non-commerial) vessels for design purposes?

 

[MTNClimber]

Not really. You should involve a local waterfront engineer, as this is their specialty. Environmental and vessel/mooring loading will depend on many factors that a local Waterfront engineer should be able to help you with.

 

[msquared48]

There is a NAFAC manual that covers that for wave action. As for wind, look to the size and exposure of the moored vessel.

Mike McCann, PE, SE (WA, HI)

 

[STrctPono]

I have never designed a pier on a lake before, only in the ocean but you might find some of the information useful from the following documents:

UFC-4-152-07 Design: Small Craft Berthing Facilities
UFC-4-159-03 Design: Moorings
UFC-4-152-01 Design: Piers and Wharves

If you are in a seismic zone, you may also want to utilize:

ASCE 61-14 Seismic Design of Piers and Wharves. It is technically not applicable to public piers but the governing agency may still approve it.

I would venture to believe that since it is a lake, you aren't going to get significant size waves so wave loading probably won't control your lateral. Maybe seismic if you are in a high seismic zone and your dock is heavy. If aluminum or wood dock then probably not since it's light. I think your berthing and mooring loads will probably govern. The berthing loads are pretty straight forward. You need to know things like ship weight and make some assumptions for things such as berthing velocity. The mooring loads are quite a bit more involved and rely on wind speed information and mooring line configuration. There is no pseudo static load that I know of that you can use to apply to the dock to simulate these. We normally employ the use of an ocean engineer to help us with these calculations and provide us the loads.

 

[Settingsun]

As usual, it depends and you haven't given much info. I'm not even sure if you mean fixed or floating. Only general comments can be made.

You seem to have an idea of the maximum boat size. Get the client to confirm and base loads on that. For proper mooring in design conditions, the boat shouldn't overhang the finger too far. The design boat might therefore be 1.3 to 1.5 times the finger length.

Marinas are generally located to be sheltered from waves. If that's the case, a general robustness load of 2 kN/m should cover incidental wave loading.

What size of mooring cleats are required? That can give a hint on what mooring loads to design for.

 

[BUGGAR]

Put some (sacrificial) piling with warning signs/lights outboard of the structure to keep big boats away

 

[DaveAtkins]

I have designed both floating and fixed piers. As I recall, boat impact on the tip of the pier usually governs. There are formulas for converting kinetic energy into lateral force.

You should also check wind load on moored vessels (within reason--you need not check for the magnitude of wind loads we use on buildings), and for impact from ice floes if appropriate.

DaveAtkins