Recent content by DaveAtkins

I just checked online - I guess gunpowder driven pins are still an option! Sounds dangerous to me[cannon]

Early in my career (almost 40 years ago), I think they were called POWDER driven fasteners, because I believe there was gunpowder involved.

I think you should use lu = 344 feet for the low roof parapet. I don't know of any literature or code that allows you to reduce the upwind length of roof due to interruption by a parapet.

I used to specify puddle welds, but now I always specify screws. Seem a little more foolproof to me.

Stiffener plates where necessary...it is difficult to be more precise without seeing a detail.

I think you need to get permission from the neighbor to install helical anchors. Alternatively, a soldier pile and lagging wall could work.

You do not need to provide 0.5% reinforcement for such a small pad. That reinforcement ratio is for an infinitely large slab with no control joints. You should design the pad for any loads imposed upon it. I typically create a 3D finite element model supported on springs.

If you can justify the load path, you are OK from a strength and stability point of view. However, the corners could open up and allow ground water to seep into the vault. This in turn could lead to sink holes forming at the ground surface.

Normally the walls in a below grade vault are two way slabs -- they span horizontally and vertically. Without corner bars, I think your walls have to span vertically, from base slab to top slab. Are there no dowels between the wall and the base slab?

And to answer your original question, I have always used the entire height of the stud, including the parapet, to determine the C&C wind load.

When it comes to connections, I do not follow ASCE 7 literally. If you do, you need to calcuate the effective area to an individual fastener which makes the wind load unreasonably high.

Agree with JAE.

If there is room at the edges of the base plate, you could use steel angles (5" vertical leg and 3" horizontal leg), with the vertical leg welded to the base plate and the horizontal leg connected to the pier with adhesive anchors.

If you use steel H-piles for your soldier piles, you could weld plates on each side of the web, creating a slot for the timber lagging to slide down inside. For the first excavation, the lagging would bear on the flanges. For the second excavation, the lagging would bear on the plates.

Yes.