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10 votes

Can steel be replaced with aluminum alloy in reinforced concrete?

A very important property of steel used in reinforced concrete is that it has similar coefficient of thermal expansion as concrete: Concrete: $14.5 \cdot 10^{-6} \frac{m}{m\,K}$ Steel: $12.0 \cdot ...
jpa's user avatar
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10 votes
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In a reinforced concrete detail drawing what does 'reinforcement to be GK 60' mean?

Check this book out; it seems to be talking about that particular grade of steel used for reinforcement. The choice of main bonded reinforcement is based on its high tensile strength and interaction ...
Manu G's user avatar
  • 367
9 votes
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Relative strength of wire mesh vs rebar for reinforcing a concrete slab

This is going to depend a great deal on what you want to achieve with the reinforcement. I'm not aware of any ultimate strength increase for using welded wire mesh allowed by Eurocode 2 or ACI318. I ...
atom44's user avatar
  • 2,641
7 votes

Can steel be replaced with aluminum alloy in reinforced concrete?

In short: you can't use aluminium to reinforce concrete. You shouldn't even embed uncoated aluminium in concrete. Quoting Corrosion of Non Ferrous Metals in Contact with Concrete, "Aluminium suffers ...
Pere's user avatar
  • 437
7 votes
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What's the name and purpose of this specific shape of hollows in a reinforced concrete slab?

It looks like a typical precast concrete "hollow-core" or "voided" slab. A quick Google image search reveals the variety of void shapes employed by manufacturers. The image on the left (from ...
CableStay's user avatar
  • 2,760
6 votes

Why would a column expand before accepting load through a narrow thunk?

The column top holds some narrow thunk and that thunk holds the driveway floor. I think we have some nomenclature that needs to be cleared up here. What I believe you're calling a "thunk" is ...
grfrazee's user avatar
  • 3,587
5 votes

Which one is preferable? Multiple layers of reinforcements or one layer of reinforcement?

On average, it's best to limit the number of layers of rebar. There are a few reasons for this. Firstly, the more layers you have, the more complex the construction of the beam becomes. The first ...
Wasabi's user avatar
  • 13.1k
4 votes
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Reinforcing beam and slab with correct steel bar structure

Model 1 is always better, but may need some modifications Whenever you have two reinforced concrete elements, you always need to facilitate the transfer of internal stresses between them. This is ...
Wasabi's user avatar
  • 13.1k
4 votes
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Is continuous beam design deemed "unsafe" by any code of practice/design practice for reinforced concrete building structures?

You question starts with (emphasis mine): Given that continuous beam predicts less deflection This is not correct. A continuous beam does not predict less deflection, a continuous beam results in ...
AndyT's user avatar
  • 3,143
4 votes

do prestressing tendons located in the compression zone contribute to compression reinforcement?

The short answer would be "yes", but there is a lot of things to be aware: First of all, you should check that the building code you are following allows you to do so. You should check adherence ...
Pere's user avatar
  • 437
4 votes
Accepted

What is the splice length for two reinforcement bars in tension of different diameter?

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 ...
Wasabi's user avatar
  • 13.1k
4 votes

Why is this structurally sound?

What you see is temporary support, only till the time the floors attain their design strength. Then all these will be removed. The rate of progress of the project must be faster than the time ...
kamran's user avatar
  • 22.4k
4 votes

Impact of having flexible electrical hose buried into the reinforced concrete slab

You haven't specified any material parameters, so for calculation purposes, I am going to assume a reinforcement yield strength of 500MPa and a cylinder compression strength for both concrete and ...
ingenørd's user avatar
  • 1,288
4 votes

How to build apartment floors/ceilings to not transfer sound?

There's a few ways that engineers quantify sound passing through ceiling/floors: Impact Insulation Class (IIC) Outdoor/Indoor Transmission Class (OITC) Sound Reduction Index (SRI) Sound Transmission ...
Michael Altfield's user avatar
3 votes

What are safe locations for openings in reinforced concrete beams?

This is the sort of thing that is best defined by each country's structural codes. I'm from Brazil, so I'm going to use the NBR 6118, our concrete code. That being said, the general gist behind all of ...
Wasabi's user avatar
  • 13.1k
3 votes
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Basic Hook development length using CSA A23.3 provisions

I'd agree, you cannot fit a horizontally oriented 5" 90° bar bend in an 8" thick wall if you want your rebar curtain to be located at the center-line of the wall. However, there is no reason that the ...
William S. Godfrey- S.E.'s user avatar
3 votes
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Are the design load values in this floor determination table (span chart) inclusive or exclusive of the given floor weight (inherent dead load)?

The load values in the table is described as the design load with no further qualifiers and that will generally mean the total load including all dead load and live load as well as safety factors. It ...
ingenørd's user avatar
  • 1,288
3 votes
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Why is there a row of circular holes in this concrete beam?

I've not seen them before but I think that they are surely penetrations to run wiring. They on top for reasons including close to the lid where wiring would be normally attached between the beams in ...
Ack's user avatar
  • 358
3 votes

What is this circular metal object embedded in spalled concrete?

It looks like a prestressed cable anchor.
Phil Sweet's user avatar
  • 4,755
3 votes

Can a nuclear reactor withstand a missile attack?

The design specifications between different plants might be different -- however I doubt there is in many (if any) a design specification that states "withstand impact of X kilotonnes TNT in ...
NMech's user avatar
  • 24.3k
2 votes

How to design a reinforced concrete ship keel?

You intend to submerge a rectangular concrete section in a fairly corrosive environment (ocean water). The section is 11.5" wide and 18" deep. During the 20 year life span of the boat, you anticipate ...
SlydeRule's user avatar
  • 1,226
2 votes

What are safe locations for openings in reinforced concrete beams?

Looking in ACI 318-14, Building Code Requirements for Structural Concrete, I find the following: Doing a word search for "opening" only shows specific results for openings in one-way and two-way ...
grfrazee's user avatar
  • 3,587
2 votes

Why do we use multiple reinforcing bars instead of one bar with a big diameter in reinforced concrete?

In addition to Wasabi's answer - which is great - large diameter bars need insane development length and lap length. A rule of thumb estimate for development and lap length is 40 diameters. For 20 mm ...
Pere's user avatar
  • 437
2 votes

Reasons for bending direction of rebars in beams

It sounds like you're inquiring about the development of rebar at RC beam-column connections. Based on my (largely academic) experience, you're likely looking at something similar to this: A key ...
CableStay's user avatar
  • 2,760
2 votes

Shear strength of reinforced concrete filled PVC pipe

A sketch would be helpful. But if my understanding of what you want to do is correct, you want to cover a 3 by 4 feet sump pit by light material which you could remove in case it is needed. The pvc ...
kamran's user avatar
  • 22.4k
2 votes

Why would a column expand before accepting load through a narrow thunk?

I find such a column hard to justify. As mentioned by @grfrazee and @ChrisJohns, what you are calling a "thunk" is usually called a bearing plate, and these are responsible for transmitting the force ...
Wasabi's user avatar
  • 13.1k
2 votes

Reinforced concrete design: will there be extra nominal moment on column in a frame structure?

You seem confused between how a structure behaves in real life and how it behaves in a structural analysis model. They key point you seem to be missing is that one must reflect the other. If, in real ...
AndyT's user avatar
  • 3,143
2 votes
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Reinforced concrete design: will there be extra nominal moment on column in a frame structure?

Just as there is conservation of energy and mass in the universe, so must you also think of "conservation of internal forces". I totally made this term up, it doesn't exist. What I mean by that is ...
Wasabi's user avatar
  • 13.1k
2 votes
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Punching Shear in Slab?

As has been mentioned in the comments, there is no specific combination of dimensions that mean that punching shear is not a problem. An Engineer may make a judgement that a check isn't required based ...
hazzey's user avatar
  • 10.7k

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