Questions tagged [civil-engineering]

Questions that fall into the problem domain of civil engineering or one of its sub-disciplines. Questions about buildings or other structures could usually use the "structural-engineering" tag also.

The civil engineering tag covers the design, construction and maintenance of the built environment; including bridges, infrastructure and tall structures.

Civil engineering is typically involved when projects are large in scale or affect a large area of land.

Use this tag when someone who has trained as a civil engineer is likely to be able to answer/ask your question. As with most disciplines, civil engineering encompasses a lot of specialisms and it may be necessary to further sub-categorize your question using additional tags.

Civil Engineering Sub-disciplines

Civil engineering is a very broad field. If your question is specific to any of the following disciplines, consider using the more specific tag instead of or in addition to this one:

  • Geotechnical Engineering
  • Structural Engineering
  • Transportation Engineering
  • Environmental Engineering
  • Water Resources Engineering

Engineering projects are often multi- and inter-disciplinary and the above list is not exhaustive.

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What is the lowest point below sealevel that we have built where a human can go?

According to google searches, the Jinping Underground Laboratories are the "deepest" building or buildings constructed, reaching 7900 feet (2400 metre) below the surface.... However, the surface in question is a mountain. While that does classify as…
Chris Gergler
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Why does this fence have a kink?

The image below shows a style of fence that I've seen frequently around train tracks. If you look closely, you will see that between the third and fifth horizontal wire from the top, the vertical wires have a kink in them where they run diagonally…
Yly
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Why exactly does a washer help distribute the stress around a bolt?

Usually the reason for having a washer under a bolt head is stated to be that it helps to evenly distribute the stress to the clamped material surface. But why is this? I would understand if the washer was significantly larger than the bolt head.…
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What is the purpose of these "steps" in rivers?

I have seen a number of structures within rivers, which resemble steps, and which allow the water to cascade down them instead of flowing naturally down the course of the river. Example 1: River Avon in Bath Example 2: River Seine in Paris (from…
March Ho
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Is there a method to determine the runoff for arid areas in developing countries?

Note: this question was totally rephrased and expanded on, addressing the comments and questions posed to the first version. The de-facto standard source for runoff calculations in South Africa is the "SANRAL Runoff Manual"…
SlydeRule
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Why does the Channel Tunnel enter the ground around 10 km from the coast?

I know that digging tunnels is always much more costly than building ways or train above ground. Why doesn't the Channel Tunnel start around the coastline? Why does it have an around 10 km long portion under land on the British side?
peterh
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What makes suspension bridges unsuitable for railways?

I recall reading in an old issue of Model Railroader an article about railroad bridges. In it, the author mentioned that you shouldn't have a model suspension bridge for a railroad track on your layout because no such arrangement would be…
Dave Coffman
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Why are earthfills fully covered in concrete where they join bridges?

Here's how a typical earthfill carrying a roadway joins a typical bridge Parts of the earthfill slopes are greenish - that's grass - and parts are whitish - that's concrete. The earthfill slope is fully covered in concrete where it joins the bridge…
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Does a roadway bridge experience more load when vehicles are parked or when they are moving?

Bridges are designed for the loads that come from the vehicles that are expected to cross them. This includes the weight the vehicle and any dynamic loads that may be introduced from movement of the vehicle. Dynamic loads may be from "bouncing" or…
hazzey
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How does a traffic light sense the proximity of vehicles?

Some traffic lights don't operate periodically but instead detect when a car is close by and then turns green. I have heard that they use a magnetic sensor embedded in the road to sense cars as they come near. Is this correct? Do they use other…
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How many train passes can railway tracks endure?

I know that the rubber on car and truck tires wear, and the road concrete wears out. I wondered: While steel is hard and elastic, it still causes friction (interaction between molecules) and therefore abrasion. Let's say we have on average 20-30…
Thorsten S.
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Why are truss bridges the way they are?

Just by taking a train ride across my home city I can see truss bridges like the one in above picture everywhere. There are numerous variations, but the most common design seems to be this. But why are they built specifically this way? I can…
S. Rotos
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How to design a house to be cooled passively?

I live in Louisiana these days, in an area that is known for its numerous antebellum plantation homes (circa early 1800s). While touring one of these homes it was clear that almost everything about the house was designed around keeping cool in the…
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How are passive houses made in very hot regions (like Saudi Arabia)?

I think, here is the main problem the difference between the internal and the external temperature. For example, in Saudi Arabia, in 50 C, a passive house needed probably much sophisticated planning as in Paris. Compared to the traditional cooling…
peterh
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Why is this bridge thickest above the support pillars instead of the mid-span where the bending stress is highest?

Why is a bridge designed like this? The depth of the section at pillars is more than the depth at middle. If I model this as a simply supported beam having load at mid span then the bending moment will be maximized at the middle and the area is…
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