Structural failure

The term collapse refers to the failure of the supporting structure of a building. Reason for the failure are forces that exceed the carrying capacity of the building material. Is not in danger of collapsing a building, it is considered stable. With the stability of buildings, employs structural analysis (study of the balance of power ).

History

Even as a man in ancient times began to build simple structures, he was confronted with this make possible stable and sustainable. However, it happened again and again that buildings could not withstand the stresses and collapsed.

Failure stages

Among the supporting structures of a building include walls, ceilings, foundations, beams, columns, beams, arches, arches and roofs. A structure often consists of many different support structures.

Failing one of these support structures, it does not necessarily lead to collapse, but the building structure is weakened. Visible or audible is the often corresponding with significant cracks in walls and ceilings, excessive deflections of components or by noise.

Pauses the excess load, other loads and effects are added or fall from more support structures collapse portions of the building or even the entire structural system of the building. Often, this process does not happen suddenly, but extends over several seconds to hours to go, so sometimes there is time to escape.

Collapse objects

One thinks at first only to buildings that can collapse, but also the support structures of bridges, tunnels, retaining walls and pits may fail in the course of their lifetime.

Effects

Buildings must be able to withstand many loads and impacts. Primarily, they carry their own weight. On components and structures below the surface act earth pressure and water pressure. These effects are also called permanent actions.

Weather charged the building with snow and wind loads and jamming due to temperature changes. Also payloads (people, furniture, vehicles) have an effect on the support system. These loads are called variable actions.

Both permanent and variable actions must be able to carry structures for the entire duration of its existence without any problems. Loads and effects that can be difficult to calculate, are actions due to earthquake, fire, impact of vehicles and ground subsidence.

Safety against failure

To prevent the collapse of buildings, must prevail in it static equilibrium. Only if the totality of the resisting forces equal to or (better ) is greater than the sum of the forces acting on it can be said with certainty that the structure is stable. This security is to create the task (construction) structural engineer. He can determine by careful calculation of whether a structure is stable or not. This is also called a stability proof. He is liable for such proof and can be prosecuted if people or objects come to harm in a collapse. To minimize the risk of calculation errors or was not aware of effects, so-called partial safety factors are included in the static calculation. These safety factors increase the security of some again by up to 50 %, so that in an emergency, a safety buffer is.

Positive effect on the stability of structures is the impact of the ongoing care and maintenance. If the major support structures regularly and fatigued or expired materials replaced early, the probability of a collapse is very low.

To reduce the risk of collapse due to earthquakes, one tries to design, for example, earthquake-proof buildings. A current example for this is the Taipei 101 in Taipei ( Taiwan). There you have tried to reduce the vibrations of the earthquake by having installed a steel ball in the upper part of the tower. This design principle reduces the effects of earthquakes on the building to such a low level that (almost ) no damage to the building.

Benefit

The collapse of buildings by gravity man takes advantage already for many years. Often it's just possible, buildings that are no longer needed, simply and quickly remove. Besides the classic wrecking ball be mentioned here is mainly in blasting, the target bearing structures in buildings damaged or completely destroyed to it bringing it to collapse.