# Tag Info

13

As grfrazee said, you won't know for sure until you do a finite element analysis. I was intrigued by this question as a colleague and I got into a discussion about this. While we both agreed the diagonal bracing would be better at resisting deflection, we wondered by what factor it would be better. We were really curious so we settled the debate and did a ...

13

Assuming the joints are welded, for the top gate to deform as you draw it the vertical bars will have to bend into an "S" shape. The flexibility in bending will be proportional to the cube of the length, if everything else is the same. The stiffness of the three sections of the top gate will be proportional to $1/1^3 = 1$, $1/0.6^3 = 4.6$, and \$1/0.4^3 = ...

8

While you've described your problem pretty well, I don't think you're going to find a satisfactory answer without having to run a fairly complex finite element analysis on both structures. The first gate structure will behave similarly to a Vierendeel truss since you have all of the pieces essentially moment-connected. The second gate structure will likely ...

6

It depends what you mean by bearing capacity. Plastic deformation increases yield strength at the expense of ductility. Also possibly toughness and fatigue durability if strained too much. Metals virtually always exhibit increased yield strength when strained plastically below their strain recovery temperatures. The phenomenon is referred to as strain ...

5

Per ACI 318 13.2, two-way slabs are designed based on "column strips" and "middle strips". To paraphrase the code: A Column strip is a design strip with a width on each side of a column centerline equal to 0.25L1 or 0.25L2, whichever is less. Column strip includes beams if any. L1 and L1 are the span lengths in the two slab directions. A Middle strip ...

4

The use of the smaller diameter is theoretically correct. What is a splice? It is when tension force in a rebar is transferred to the concrete via adhesion and then to another rebar. Since concrete is very weak against tension, large lap lengths are required such that the stress at any point in the concrete is not excessive. However, once the splice is over,...

4

Bamboo in its natural shape is very prone to splitting. Having any kind of hole will reduce its high bending strength resistance significantly. In addition, bamboo culm does not have a constant cross-section in the longitudinal direction, makes it harder to create a reliable bond. J.F. Correal "Bamboo design and construction" has few suggestions for bamboo ...

3

Disclaimer - No contract exists between us. This post is provided as information and opinion only and does not form "advice" in any way. Although I am a Chartered Civil Engineer I have zero professional experience with masonry. My views here should be treated as those of a keen DIYer (which I also am). I suspect it'll probably be ok without any lateral ...

2

The natural way to stabilize it is to pressurize it. The normal atmospheric pressure is ~ 100 kPa. To do that a gigantic air-tight liner should be inserted within the lava tube. It would be a little larger than cavern on order to transfer pressure loads to rock walls and sealing. A tricky equilibrium must be designed between gravitational induced rock ...

2

There are really two aspects to this: Will increasing roll stiffness improve handling to an extent which offsets any increase in weight by adding extra chassis members ? If yes, what is the best strategy for improving the stiffness of the chassis? The issue here is that this is a fairly simple ladder chassis so we are really looking at creating some sort ...

2

I am not sure which guidance manual you are looking at, but it must in turn be referring to EN1992-1-1 section 9.2.1.1. This section defines the minimum amount of reinforcement in a beam or slab in order for the beam or slab to be considered reinforced concrete. And it does indeed use the value of 0.13% (with adjustments for concrete and steel grade). So it ...

2

The fact that design of concrete slabs or beams uses straight reinforcing bars running orthogonally doesn't have much to do with the geometry of slab, beam or a deck, etc. It has to do with the fact that straight bars can take large amount of tensile stress and with their counterpart compressive concrete take large moments, without any tendency to peel ...

2

It depends on the type of the joint: The smooth dowel is used in an "expansion/contraction joint" to allow for free (lateral) movement due to thermal expansion/contraction of the concrete on either side of the joint. A smooth dowel has less surface for bonding, and no rib (small deformation around the bar) to restrict the movement. Sometimes ...

1

Depends on how wide your wall is. But there are pumps with small flexible hoses of 20 feet long. You can use a 20 foot pipe or handle and reach the spray nuzzle to the right space. Here is a link to one manufacturer, concrete pump.

1

No, the zip tie and conduit won't cause the pipe to develop an internal restriction. Even squeezing the outer cover will not compress the inner sleeve... There are metal pipe clamps that will compress the inner but they have serious leverage that you won't get from a nylon zip tie.

1

I would recommend a temporary shoring of the wall by attaching a vertical 3" x 6" board to the wall near the location of new column. This board will be attached to the wall by 5x 1/4 inch anchor bolts, and will be laterally braced by a few diagonal 2x4" braces which are secured to the ground. later this board shall be removed with the anchors, and any holes ...

1

The overall stiffness of the frame is determined by the stiffness of the side beams augmented primarily by the three tubular cross members. An interesting academic exercise would be to evaluate how changing the diameter of the cross members affects the overall stiffness.

1

Bringing rebar to full plastic behaviour and then releasing doesn't make it any less strong. It may make it stronger through work hardening. If you don't repeat this too often, you won't introduce fatigue. You might recognise this or similar diagrams from your book. The allowable stresses for rebar allow for them to be fully bent to various ...

1

This question has no clear answer in its current form. The strip method is a lower bound approach (meaning that you approach the optimum solution from the safe side) based on beam analogy. So in theory (given endless ductility, etc.) you could arrange your strips in any way you want and you would always end up with a safe (but possibly horrible in all other ...

Only top voted, non community-wiki answers of a minimum length are eligible