Dock broke - question about aluminum trusses or other aluminum DIY solutions

[Pricestavern]

DickR - what is the frame of your crank-up made of? I too have a crank-up (20') but the frame is made of a single, welded aluminum box girder-like structure. The one shown in the video is sectional. I think that would make a difference in its rigidity, no?

[DickR]

The dock frame is welded aluminum. The top chord is 2x4 all around. Perhaps 16-18" below that is a 2x2 chord. The two are connected vertically with pairs of 2x2 pieces on each side, where the legs go. There are four pairs of 4x6 PT wood legs out over the 30 length, or a bit short of eight feet apart. The pairs of vertical 2x2 pieces have a small gap between them, and the bolts holding the legs strapped to the frame pass between the pair. A piece of peel & stick rubber roofing membrane keeps the PT wood separated from the aluminum.

Across the 6' width are 2x2 cross members, except 2x4 at the two ends. There also is 2x2 cross-bracing. The lifting ladder is rectangular, made of 2x4 sides and 2x2 "rungs." This is 24 ft long. It sets down over the lateral members and cross-bracing and, with the two sides of the dock, helps support the deck sections.

In the first pic, you can see the two whip mounting plates, one near the outer corner, the other 10' in. The second pic shows the frame mounted on the header bar assembly, which was welded up in place for the set of boulders at the shore. In that second pic, that's not the lake bottom under the header bar. It's a lot of rock debris from drilling into the boulders for the expansion bolts and from chiseling out a place at the top of one boulder to make room for the header bar. The ice was well over a foot below that dirt, right down to the lake bottom.

[sluggo]

Dick You didn't mention that we cut and lap all of our joints before the process of the mig and tig welding and we also cross brace and gusset the joints so the dock can handle pretty much anything you put on it ! Thanks for posting your pics its great to see are dock work from Center Harbor Dock and Pier on the forum....

[sluggo]

quality of the welds when finished ....

[sluggo]

This is a crank up we built this year to replace an old wooden seasonal to add in a finished product to the thread.

[TiltonBB]

The longer dock is 47 feet and required a boom to lift it. The boom collapses for summer and is stored underneath the decking.

The wider dock was actually two separate pieces that were bolted together permanently after they were placed in the water.

When the dock is raised for the winter make sure you attach lines to the shore from the outer end. The lines are to prevent the dock from swinging side to side when it is windy. That will break welds or otherwise put a lot of stress on the dock.

After a lot of years of lifting the decking, recently I have been using a hand truck (two wheeler) to remove and replace the decking. It sure beats carrying them!



k.