26
votes
Why are some public benches made with arm rests that waste so much space?
I am not sure about this particular design. But in public places, the benches are designed to provide temporary comfort but discourage using them as a vagrant or homeless hang out, hence designed ...
- 22.1k
11
votes
Why are some public benches made with arm rests that waste so much space?
Benches are not usually engineered as such. They are being made by furniture designers, (landscape/interior) architects etc.
Now generally these professions put a lot of work into making their items ...
- 3,597
6
votes
Why don't public transport networks have more routes to each terminal?
Keep drawing combinations. You forgot Østerås to Vestli, Østerås to Bergkrystallen, and every other combination of possible origin and destination.
This breaks down in a hurry. By the time you ...
6
votes
Why don't public transport networks have more routes to each terminal?
The main reason is economics. Who is going to pay for all the additional lines? The other part to this is, will the additional lines have enough passengers to make them profitable and sustainable?
If ...
- 9,642
5
votes
Electricity generation via piezoelectric roads, stairways, is it plausible?
Q1: Yes.
Q2: Yes.
Q3: It depends but generally not much.
Q4: No.
Without getting into the technical details of how you recover the energy, consider it from a conservation of energy perspective.
...
- 766
4
votes
Why do water mains break in the winter?
Water main failures are greater in the winter months than in the spring or summer. As a water utility professional in northern Illinois we have around 120 failures each year with 20 + years of data. ...
- 41
4
votes
Why are some public benches made with arm rests that waste so much space?
In the bench that you show, the slats are supported and held in alignment by the end brackets. The armrests are supported by, and in line with, the legs. You could incorporate the end brackets into ...
4
votes
How are subsea HVDC cables laid without cutting internet cables
It seems like they are not buried in deep water so I guess the carefully arrange crossings to only occur there.
From this document, page 41:
The cables are buried in the seabed sediment up to depths ...
- 137
4
votes
Accepted
Why Not Refine Crude Oil At Source
Some places, like the North Slope of Alaska, are inhospitable to the construction of refineries. It is cheaper and more convenient in this case to transport the crude to a distant refinery via a ...
- 14.3k
3
votes
Effectiveness of LiDAR in manhole structures?
There's nothing like kicking the dirt. I would advise actively participating in a manhole inspection, at least once so you know what it like. Do an inspection with an experienced person. By doing so ...
- 9,642
3
votes
Why have they stopped having curbs on streets?
On the following roads, a curb is not desirable - highway without pedestrian traffic, rural highway (ease of pulling to the shoulder and not to restrict water flow to ditches), City streets designated ...
- 8,109
3
votes
How is the energy production of solar and wind compared with the prospect of nuclear fusion?
The reality of generating electricity from nuclear fusion on an industrial scale is still a very long ways off. It is speculative high cost, high risk venture, with a potential high payoff far off ...
3
votes
At what cold ambient air temperature will power lines fail?
Here are some pylons in Norilsk, Northern Siberia, where temperatures get down towards -50°C
(source)
It's all a question of design and engineering: pylon spacing, the range of max and min ...
- 3,751
3
votes
Why do we pave roads instead of making them from removable parts?
Other answers have well described a road is a lot more than just the surface layer and the vast majority of the cost is the planning and logistics involved rather than the actual materials.
Current ...
- 15.2k
2
votes
How can one reliably prevent pedestrian access to a parking garage, but allow vehicular access?
Pressure sensor that triggers alarm if something less than 1 ton but more than 10kg enters the garage.
Electrify the floor, anyone walking in will be fried without a Faraday's cage protection.
Fill ...
- 53
2
votes
How can one reliably prevent pedestrian access to a parking garage, but allow vehicular access?
Dual gates, with the outer one always closing before the inner one opens.
For extra security, a computer vision system could check that no people are present in the intermediate space before opening ...
- 1,943
2
votes
Accepted
How is the energy production of solar and wind compared with the prospect of nuclear fusion?
Fusion is widely extolled by advocates as being safe (but is that collective opinion justified)?
I would prefer to begin my discussion comparing fusion with renewable energy systems with an ...
2
votes
Accepted
Is there a way to reduce leaks and infrastructure damage when turning water on and off at the scale of city?
It is difficult to provide a useful answer to this question without additional information. For example, what is the system pressurization - operating psi/bars? Having installed ductile iron water ...
- 652
2
votes
Is there a way to reduce leaks and infrastructure damage when turning water on and off at the scale of city?
The problem with older and under-maintained (this is South Africa after all) systems is that the pipes get brittle, rusted and joints fragile and the network won't be able to handle the transient ...
- 638
2
votes
Why culmination points in tunnels?
Laterally circumnavigating problematic bedrock is not always possible or practical for the following reasons:
This can increase the length and cost of the tunnel
The problematic geologic zone may be ...
- 9,642
2
votes
Accepted
Why were so Many Older Bridges Built so Low to the Water?
Cost
It costs more to build a 23 mile bridge 20 feet (30 feet, 40 feet?) higher in the air.
When it was built, the Lake Ponchartrain Causeway wasn't blocking anything - there was zero freight traffic ...
- 6,534
2
votes
Why are some public benches made with arm rests that waste so much space?
Here is another thought. Have you had your arm on the armrest and someone walked by with a bag or otherwise just carelessly bumped into or smashed your arm?
It might be nice to have a little of the ...
- 121
1
vote
Accepted
Effectiveness of LiDAR in manhole structures?
I don't think you want LIDAR. From what I have seen (and my experience is limitd), LIDAR, when it is referred to as LIDAR at least, is only accurate to a few cm. You aren't going to see cable defects ...
- 5,237
1
vote
Why don't public transport networks have more routes to each terminal?
Given that the six parallel lines in the centre of town actually consist of only two tracks (one eastbound and one westbound) running through "the tunnel" (Oslo T-bane or Oslo Tunnelbane) and that ...
- 10.3k
1
vote
Why don't public transport networks have more routes to each terminal?
Best guess to the problem of adding more: Logistics and economics. First of all, never underestimate the cost of public construction project such as tunnel buldinn...
1
vote
Accepted
Oil refinery pipeline direct to gas stations
To begin with, gas/petrol filling stations may or may not be located at one site for a long period of time. Dealing with a disused pipeline for a closed station will be a problem. Continually ...
- 9,642
1
vote
How can one reliably prevent pedestrian access to a parking garage, but allow vehicular access?
Since cost is not an issue how about an armed guard. Not every problem is an engineering problem.
- 880
1
vote
How can one reliably prevent pedestrian access to a parking garage, but allow vehicular access?
You can install a passive solution like a Cattle Grid for people that would heavily discourage anyone from trying to walk on it.
But then you might have to deal with the idiots that might get stuck ...
- 1,109
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