38

They are called bollards. Their function is to provide safety for pedestrians from traffic, distracted drivers who may encroach into the sidewalk, or runaway cars e.g a driver who inadvertently leaves his/her car in neutral without the emergency brake set. Many municipalities require them and have codes and specifications defining their dimensions and ...


30

This is to make sure they know what the foundation is made of. For all they knew there may have been an old tunnel underneath that would have collapsed when the new building is put on top. London is built on top of an old marsh, this type of soil is very prone to sinking and uneven settling, digging down and reinforcing the foundation alleviates that. It ...


28

They are called Bollards. But these aren't defensive as suggested. Look closer. There's no curb. This is a new style of store (from the architecture) and curbs have been eliminated for ADA reasons (benefit of wheelchairs). As such, there is literally nothing to prevent a car from drifting forward and hitting the building; it's not even clear where you ...


21

There are a few reasons why the footprint of large buildings are excavated and replaced. All of the old building must be removed - Typically, older buildings will have been built with weaker materials or less stringent building standards than are currently used. Depending on the age of the existing structure, complete plans may not even exist. This means ...


12

I do not know, I've never been there and I have no other information other than what is in your question. However, ... I'd say that best guess, until somebody who knows more presents, is your suggestion of now-unused telephone booths. On the wall are two plates. These are at the same height in each case and consistent with connecting a telephone. Other ...


9

Bollards and other defensive oriented structures significantly predate the 2016 Nice attacks. They have been in place at the construction of many buildings in the US and across the world for decades including government and multi-national corporation buildings. You probably just never noticed them. It is my opinion that you see more of the type above due ...


8

It makes me wonder why some sort of counterweight system isn't used instead. I'd guess it's because residential garages are normally a bit limited on space and the counterweights need somewhere to go. Torsion springs are nice because they take up relatively little room on the ceiling of the garage, as opposed to counterweights, which would need space to ...


8

The weight of the gold would be about 52,110,000kg, over 900 meters square of floor area. This is about 82.4psi of floor pressure, or, under standard gravity, 57.9kN/m^2 live load. This is only an order of magnitude greater than typical industrial (storage, assembly) buildings that accept 7.5kN/m^2 across the floor surface. The total weight of the gold is ...


8

xkcd has a fantastic description of how lightning works. This video is also quite good (especially as of 0:56, but the rest is worth watching as well) since it shows lightning in super slow motion, so you can see it "searching" for a path down to earth. The important thing here is to learn that lightning searches for a path in steps. Xkcd mentions 60-meter ...


7

Mainly cost difference. And also, a fan is sufficient for the job. The problem being solved is thermal stratification. That's caused by a lack of vertical mixing; the warm air rises to the top, the cold air sinks. Normally, there's quite a bit of movement in the first two metres or so from the ground - thermal stratification starts when the ceiling gets to ...


6

Think about the pressures. With the pump above the supply line, the pressure at the input of the pump will be lower than the supply. At roughly 2 PSI per foot, you're down about 18 PSI. Since air pressure is about 15 PSI, the system will at least work as long as the supply pressure is over 3 PSI, but that's still not a good situation. If the "supply" is ...


6

As @SamFarjamirad states it's best to consult a knowledgeable construction engineer where you live, or in your region, because such people would know the building codes & construction practices for your region. A column or pillar for a two storey house may not be necessary if the load bearing walls are designed & built properly. This may include ...


5

Seems like to me the reason is a counterweight provides a constant offset to the door weight and that weight changes as the door is brought back to horizontal. I suppose there would be a way to design a variable counterweight mechanism but that would end up more complicated(costly) than the springs.


5

Unity Equation The Unity Equation is a very standard method of analyzing a section under combined loads. Even though the masonry code doesn't specifically call it out in the reinforced pages, it would be hard to argue that it wasn't a reasonable assumption. $$\frac{f_b^1}{F_b^1}+\frac{f_b^2}{F_b^2}\le1$$ The equation could even be $\le\frac{4}{3}$ if stress ...


5

If one side of foundation has soil packed more loosely than the other side, the foundation may cause the ground to sink, and building may crumble. Even if it has a steel-reinforced concrete foundation, the building may tip sideways, causing uneven floors, or wood to shift and split, even if concrete remains in same shape. In my area we have a lot of caves, ...


5

"Swimming" would be about impossible. IF the gold conveyed buoyancy as water does, which it wouldn't, - at full density you'd "float" with about 5% immersed. If mean density due to packing was about 50% then you'd "float at about 10% immersed. However, if you dug/burrowed/dived (ouch) a hole and coins then piled in on top of you the mechanisms that cause ...


5

Sounds like you have covered your bases. The only thing I can recommend is gathering data and considering some scenerios to evaluate that data against. I am not an HVAC guy but can give you the 1000ft engineering perspective. Any of these trends would be helpful in debuggig the situation: Relative humidity and temperature at a discharge of the HVAC system ...


5

That wall has not been designed to be load bearing by a structural engineer. As you say, it only has a single header (top beam) rather than a double, and the verticals aren't cut accurately enough. What worries me... is that you say this was an attic conversion. Attic conversions are sometimes done by people who don't understand what they're doing and don't ...


5

The elevator control system stores various bits of information in a logical fashion. The system will be optimised to maximise the utility of the lift. This generally means moving the maximum number of people to their desired destinations in the minimum time. The logic is smart. If someone on the tenth floor presses the ▾ button the elevator will run ...


4

CFD I ran this situation through a couple of simple 2D CFD models. As you can see from the pictures below, one way to keep debris from gathering in this area is to increase the velocity of wind in the corner. To do this, you need to place an obstacle that will direct the wind into the corner. Original Situation: Obstacle Added: Even with this, there will ...


4

(1) What is implied by "Underground water level varies from 5-6m" for the construction? Typically this means that the groundwater table starts between 5m and 6m below grade. In other words, if you dig over 5m into the soil, you will likely hit the water table and have water in your excavation. Construction sites use water mitigation strategies to deal ...


4

In the 1940's and 50's, dynamic system controllers were invented which used air pressure to work. It was possible in fact to design and build not only analog control mechanisms but also binary logic devices that ran on compressed air and which could perform simple switching functions. These devices were less expensive and more durable than electronic logic ...


4

What is the technical term for this? Bending downwards is called sagging. (Technically "sagging" isn't moving downwards; it's bending in a shape that looks like the mouth on a smiley face). One thing you'll see with concrete structures is creep. This is where under constant load, the deflection increases over time. Is this a problem or not? Why? Sagging ...


4

They are to prevent "smash and rob". A situation where someone steals a vehicle and drives through a store front to rob the store. Usually an accomplice drives a second vehicle to escape.


4

structural ceramic does have some applications in things like engine parts, but its cost and manufacturing difficulty makes it a less ideal choice for something as large as a building foundation The thing about concrete is that you can mix it with water, and pour it into a space to make a foundation. Ceramics have to be kiln fired at 1300 + C for hours. It'...


4

One of the foundational principles of structural engineering is obviously safety. And one of the foundational aspects of safety is the ability to show warning signs prior to any accidents. In the case of structural engineering, that means designing structures to crack or sway or groan or what-have-you prior to collapse. In fact, when designing beams, one of ...


4

New homes are inspected by local authorities to comply with local building requlations. As Mike says, give them a call. The National Electrical Code (NEC) are standardized guidelines for electrical construction created by the National Fire Protection Association (NFPA). The NEC are guidelines, not laws. The NEC is adopted into law by states and local ...


3

I’ll be installing a custom counterweight for my new garage door – it requires some clever engineering to make it work since a residential garage door doesn’t have a fixed weight: its track bends right above the door opening, and the part that is in the horizontal raceway provides no vertical load to the counterweight. So, as the door opens, it gets lighter ...


3

The paths of lightning can not be predicted with certainty, so it becomes a question of probability. I'd say that your rods are quite unlikely to be hit by lightning, considering that you are 3 floors down from the top, and there appear to be other metal structure between you and the sky. I'm assuming the railings in your picture are metal. If lightning ...


3

Yes, this is permissible NFPA 13 7.1.3 explicitly permits this: 7.1.3 Auxiliary Systems. A wet pipe system shall be permitted to supply an auxiliary dry pipe, preaction, or deluge system, provided the water supply is adequate.


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