I'm engineering a deck that is designed independent of the building with cables in the "X" formation designed as tension only cables for the lateral system. The cables are attached to plates that are bolted to wood posts and wood beams. I designed the lateral system with an R of 1.5. Table...
I have a client that drove about 50 10" diameter piles along their water front property and now want to build a two story boathouse on it. They were driven 6-8' into the soil with a 4500lb drop hammer. They stick above the soil about 15 feet, than there is a dock and above the dock is a two...
We have a 12" thick wood framed wall which structurally only needs to be a 2x6 wall but due to desired insulation values the architect is wanting them as 12 inches thick. The contractor does not want to pour a 12" thick concrete wall, rather he wants to do an 8" ICF wall with 2" of insulation...
For some thermal break issues the contractor wants to install a 1" thick layer of insulation on top of metal purlins and than screw down the 1.5" 20g metal deck on top of the insulation. This is for a large tilt up concrete building with steel girders every 20' and metal purlins spanning the...
I am looking for some assistance on slab / foundation joints for use in a water tank.
The tank wall has 12” cast-in-place concrete walls with an ID of 30’. I currently show a thickened continuous ftg that is 6’-6” wide x 1’-0” thk transitioning at a 3H to 1 V slope to a 6” slab (all poured at...
The quick question: when do cracks in a cmu wall become a structural concern? Most posts I viewed deal with the cause of the cracks. Once that cause has been determined and fixed than when is the building structurally in jeopardy? I'm not thinking about minor shrinkage cracks but larger...
I've searched many previous threads on this subject but unable to find a solution. I want to put a bolt through a CMU wall (a grouted and an ungrouted case) and a plate and nut on the outside face. It is to hold a cable that will be in tension. Does anyone know how to put a capacity to this...
I inspected a PEMB that had large (8'x8'x2') footings at each column. Columns were spaced 25' apart on gridlines that are 50' apart. The contractor poured the footings monolithically with the 5" slab on grade (#4 @18" ocew). Control joints were 15' square grids. I'm told that cracks began...
I have a client who has a 9' long channel and needs it to be 12'. It will act as a beam with a uniform load and be pinned on each end. For now he plans on welding a splice plate to connect the two channels (a 3' piece and a 9' piece) on one side of the web and on the top of the top flange and...
I have a large underground concrete tank that is designed to be water tight. The water table could be above the lid resulting in extremely high bouyancy forces. To help get an idea the tank has about 3,000 ft^3 of volume - I would need a 7' thick x 20' x 12' concrete deadman to anchor it too...
I've got another engineer who has stated that hairpins are not allowed per the code. I wasn't able to get a clarification nor have I found anything that validates this comment but the client wants some proof of my design (using hairpins) before he accepts it. To clarify - my client has used...
I've looked in the MDG and other masonry books and can't find a solid answer, maybe someone can help. Can cmu shear walls be non-stacking from floor to floor? All the examples and books I've read show a multi story cmu building with openings that stack from floor to floor, what happens if the...
I'm just wondering what other engineers do for footing design when the governing factor is the allowable bearing pressure. Do you include the weight of the soil that bears directly above the footing or do you ignore it? My company includes it and has included it for years but we did a survey...
I have some large steel columns sitting on short (3' tall) piers that are roughly 2" larger than the base plate (in all directions). They have lateral/vertical/uplift forces. I'm trying to determine wether or not the anchor bolts will break out or fail per Appendix D in the ACI. What impact do...
I've been doing a lot of steel buildings lately where the prefab steel column sits on a pier (short column). ACI 10.9.1 says I need .01Ag of steel. Well my client is saying that his other engineer specifies half the reinforcement that I do. Is there some provision I'm not seeing or is the...
I have a large W shape as my beam with 6X14 timbers (rafters) every 2' on both sides of the beam, each timber has a 6k reaction. The owners want to place these rafters on the bottom flange of the beam. I've never done that, all I've ever seen is the rafters or joists bearing on top of the beam...
In a cantilevered concrete retaining wall what are some standard practices that any of you take for including the influence of either a 90 degree bend in the wall or a counterfort. I have typically used a 1 to 1 ratio but think that may be unconservative. I was wondering what other engineers...
In a laterally restrained wall what boundary condition should be applied to the base between the wall and footing? If assumed to be fixed (as a retaining wall) then how does it get built to create this fixity? Would a double mat of reinforcement be required or a monolithic pour which is seemly...
