Cases of faulty cracking and danger in buildings:
Sometimes cracks appear in the buildings, sometimes dangerous and sometimes dangerous. As a simplification we will refer to the most important cases of cracking in the buildings and what observations should be made to ensure the structural safety of the building.
1 – horizontal cracks in the horizontal elements: This crack occurs in the areas of convergence between bridges and walls of the block and the cause of cracking is the expansion and contraction and the difference between the elastic factor between the materials and cracks are shown on both sides of the room is not dangerous but flawed ..
2 – Vertical cracks in the vertical elements: occurs in the areas of convergence of columns in the blocks are cracks flawed but not dangerous as well.
Abstract: horizontal cracks in the horizontal elements and vertical cracks in the vertical elements appear on both sides of the room
And are narrow cracks (1 – 2 mm) defective and non-dangerous .. It is processed by removing the layer of Zlika (telepathy)
And laying a layer of reinforcing iron for the clay (chicken nets) and the re-implementation of armed clay.
3 – diagonal cracks at an angle 45: They are cracks are dangerous and often have many forms:
(1 – 2 mm). These cracks are caused by the lack of the length of the upper part of the door or it does not exist at all. This leads to the cracking of the clay and the block sometimes under the door blows. Successive .. and are cracks are not dangerous.
This cracking is handled by executing an armed chandelier above the door and carrying out arming chicken nets for the clay.
B – Slit cracks next to the lower openings of the windows: dangerous cracks caused by the presence of differential landing in one or more building rules .. This crack requires the consultation of a specialist engineer and expert, especially if the length of the crack is large.
C. Two sloping slabs starting from the angle of the upper column at the middle of the lower bridge at a 45 angle from both ends of the wall:
A very dangerous fracture caused by a weakness in the Salafi bridge or the ground chinag, and the Chinag is often broken.
A complete study is underway to strengthen the building scientifically.
D – two slits are sloping starting from the corner of the lower column middle of the upper bridge:
This is due to a differential landing in one of the bases (the place of cracking) and is usually accompanied by a crack in the edges of the lower windows.
4 – horizontal cracks in the columns: a very serious crack caused by the collapse of the base completely led to pull the column down the column is reinforced by metal bracelets or other ways.
5 – Vertical cracks in the bridges: It occurs either at the end and is dangerous due to exceeding the shear forces of the permissible or in the middle and is more dangerous due to exceeding the torque of the permissible: This crack starts from the bottom in the form of hair growing steadily until the middle of the height of the bridge .. You can never ignore it and ask for a specialist engineer.

General Notes :
Sudden collapses in buildings occur as a result of poor concrete.
Iron deficiency causes many warnings before collapse due to iron susceptibility to elongation before breakage
While the concrete collapses under pressure without elongation and without any early warning.
Many collapses occur due to the caves or the existence of layers of lime living under the buildings, which are heavily affected by groundwater.
These collapses have nothing to do with the rigidity of the building. If the soil is weak, it must be reinforced and reinforced, or foundation methods such as deep mats or pegs should be used.