There may have been occasional incidents of severe deflection, but there has been no record of a concrete slab balcony collapsing due to live load in the author's observations during the last fifteen years. The balcony may collapse under its own weight if reinforcement is missing or misaligned. Concrete balconies are very strong when properly designed and built, but like any other building type they can fail if not constructed properly.
It is important to remember that concrete continues to shrink even after it has set, so over-sized reinforcing is required to produce a strong structure. If you are building your own home, then you should consider consulting an architect or engineer to ensure you include sufficient strength in the floor and roof slabs to be able to support your anticipated loads. Otherwise, you might be forced to pay for improvements that could have been avoided if only you had known how much force certain activities would put on your house.
Concrete structures are involved in many accidents every year. Slips, trips, and falls are the number one cause of injury from which to concrete structures suffer. This includes both new construction and remodels. People tend to forget that concrete remains a brittle material under stress and can easily break if not reinforced with caution.
The best way to avoid an accident is by including safety features into your design. This means ensuring that stairways are well lit, handrails are used, and floors are not waxed.
A building will collapse if too much weight is placed on a flawed framework. When a structure collapses as a result of a natural disaster or fire, it is sometimes possible to establish that architectural errors or poor construction were to blame. However, in most cases, the cause of the collapse can not be determined so easily.
The main types of collapse include:
Falling down: This occurs when an entire section of the building collapses due to excessive loading or damage from an earthquake. Even though this type of collapse may look like a violent event, it is actually a very slow process that can go unnoticed.
Destructive shaking: This happens when an extremely large and powerful force shakes a building violently enough to cause structural damage even after the force has stopped. An example would be a strong wind blowing against a roof that is not designed to support such weight.
Repairing or retrofitting: If a building uses old technology or techniques, then it may be necessary to replace some parts of the framework or upgrade certain procedures to avoid future problems with safety or stability. For example, window frames are now made out of steel instead of wood because wood gets wet when it rains and expands/contracts with changes in temperature, which can lead to cracks forming in the frame over time.
Excessive weight-building might collapse due to being compelled to bear too much weight. This is frequently caused by underestimating "live loads," or weight from items that are not part of the building's permanent construction. For example, a heavy snow load on top of an insulated roof can cause it to collapse.
The simplest way for a structure to collapse is with the loss of its underlying support. If the foundation cracks or crumbles, the structure will follow. In some cases, the structure may remain standing even if the foundation fails, but it is certainly possible for it to collapse as well.
Other factors may also lead to a structure's collapse include damage caused by an earthquake or similar event, excessive wind loading, etc. The key factor in all these cases is that the structure is being asked to do something it was never designed to carry. Whether it collapses or not depends on how strong it is really supposed to be used.
A building or structure will always try to return to its original state after being subjected to external forces. However, this returning process involves energy consumption and is therefore not free. Over time, this may have an adverse effect on the environment because greenhouse gases are produced as a result of this energy consumption.
As long as a structure remains upright and does not suffer any major damage, it is considered safe and usable.
The answer is that weight can undoubtedly cause a floor to collapse. Because many materials deteriorate with age, the older the structure, the less the floor can sustain. Weight limitations vary greatly even within the same floor. For example, a concrete floor in a building site may be able to support a load of 500 pounds, but not 1,000 pounds.
When a floor collapses under excessive weight, it's usually because the supporting walls are also collapsing. The exact cause of such damage may be difficult to determine, but it's probably due to poor construction practices or an outdated design. In any case, if you're asked to provide more weight than what the floor was designed for, avoid standing on it!
The best way to ensure that you don't cause the flooring in your home to collapse is to have it inspected by a professional structural engineer at least once during the lifetime of the building. He or she will be able to tell you how much weight it can safely accommodate before it becomes a problem. If the floor shows signs of stress, such as redness or swelling around its perimeter, this engineer should be contacted immediately so that any necessary repairs can be made before further damage occurs.
Overall, weight is one of those things that cannot be seen from outside a building, so check with a professional whenever possible.
The fires were judged to be the primary cause of the collapses, with sagging floors pulling inward on the surrounding columns, causing them to bow and ultimately buckle. A total progressive collapse was unavoidable as the upper portion of the structure began to slide downhill. There was no evidence of explosives, bombs, or terrorism.
What is unique about these buildings is that they collapsed straight down, instead of gradually like a house of cards, which is what we would expect from ordinary fires. The reason for this is unknown but may have something to do with the fact that both buildings collapsed on an angle, indicating that their cores had been completely destroyed by the fire.
The fires were so intense that they must have reached all the way to the inside of the building, destroying any possibility of recovery for those trapped inside.
These fires were not only high-intensity, but also remarkably fast-moving. Firefighters on the scene reported that there was no time to escape. Even those who made it out alive said that there was nothing they could do to save themselves or their colleagues.
All told, 1,455 people lost their lives in these two terrible events. They include 997 people from America and another 558 from elsewhere around the world.
These tragedies have been used by politicians to argue for more security at airports and other public places.