concretemounting
I'm planning a wooden table with concrete legs. I will use a U-shape or O-Shape for the legs.
Should i use screws to attach the legs to the slab or is there a better way?
I thought of placing a metal angle in the concrete but i dont know if its the perfect plan to prevent the table from wobbling (if thats the right word)
EDIT:
i didn't use the concrete legs idea and made a table with steel legs.
As long as the wood that you use to construct your bed frame is strong enough in its own right to be used as a bed frame you should have no problems supporting the frame from both ends by bolting into the concrete wall.
Bolts that are 1/2" in diameter should be plenty strong in shear to support a bed frame mounted in this manner. Three or four equally spaced bolts per end would give you an even distribution of support for the frame at each of the concrete walls. If you can penetrate the walls by two to three inches and install good quality anchors there should be no problems with the bolts staying tight and in place. Using a drop-in internally threaded anchor type should provide you the ability to use standard threaded bolts that can then be removed easily with the anchor staying in place in the wall. If you look at the RM-12 type you'll need 5/8 inch holes in the wall that are a minimum of 2" deep. This type of anchor also includes the need of a setting tool to expand the anchor into the concrete before installing the threaded bolts. The RM-12 offers a 3/4" thread depth.
For best application of the bed frame it would be recommended to build it to fit to the shape of the walls so that the end pieces can be solidly bolted up to the wall. If you elect to stay with the rectangular frame and then I would recommend that backer be placed behind the end piece where each bolt is located. Obviously a wedge piece, as you surmised, would be the best as a full length backer. If you do go with just backer blocks or the wedge one way to get a nice look would be to add an additional facer trim board as shown below. If the gap out of square across the width of the bed is only 1" you will never notice it once you get a matress and bedding up on the deck.
I put tie-downs in my driveway to guy down my boat canopy during the summer. I dug 2 foot holes, crisscrossed rebar diagonally into the ground, poured concrete, and sunk heavy duty eye-bolts with alternating nuts and washers into the concrete. I will be doing something similar this summer with posts, sinking them into concrete, with rebar through them.
Best Answer
With out any design sketch, a good way to bond wood to concrete is using
threaded anchorsorthreaded insertsThe difficult part is placing these inside the concrete column, to be level and not get dirty from concrete.
So using a fairly large size, so its easier to clean later, and easier to screw into.
Basically you would then insert a metal shaft in the wooden part and use a long screw that goes throught the wooden shaft freely but its head will clam the shaft.. and when you screw it into the concrete threaded anchor you essentially pull the wood tightly to the concrete pillar..
I could not find a diagram that illustrates this but this picture depicts the concept
So imagine the top of the screw, the part of your wooden table.. and the bottom part the concrete pillar, but using the threaded insert, instead of that bolt in the picture.
I have seen this used in building public park benches, with wooden planks fastened to concrete pillars... it is highly durable and very vandal proof.
But you might consider putting in three studs per column.. Three, in a triangle shape.. as this helps stabilize heavy objects. Or four in a SQUARE shape.. Using 1 you will need some sort of cross member or brace.. 2 is almost useless as you still need cross members or braces.