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Monday, 20 May 2019 01:00cat

Types of reinforced concrete structures collapse

Written by  TheStructuralEngineer.info
Types of reinforced concrete structures collapse Types of reinforced concrete structures collapse

Many types of failure can trigger the collapse of a reinforced concrete building.

Any structure may experience a phenomenon known as structural failure or collapse. Structural failure is the total or partial loss of the structure's integrity and its load bearing capacity. Such an incident occurs when the material of the construction exceeds its strength limits and breaks or experiences excessive deformations.

When it comes to concrete buildings, the usual types of structural failure are the following:

  1. Crushing failure of columns: When reinforced concrete columns are subjected to intense loading conditions, both steel and concrete yield and the column fails. Earthquake loads that apply lateral stresses highly affect the solidity of the column which may get crushed and lose its bearing capacity. If the structure is isostatic the framework will behave like a mechanism.
  2. Shear cracking of columns: Reinforced concrete columns may undergo shear failure mostly caused by seismic forces. The cracks usually appear diagonally and may take a spiral shape when the structure experience twisting.
  3. Cracking of column-beam junction: The joint of a column and a beam usually experiences high bending and axial stresses which may lead to severe cracking reducing the strength of the junction.
  4. Short Column Effect: This phenomenon is related to the construction of infills walls attached to the columns. The interaction of the column with the wall leads to high stress concentration. The column is restricted by the wall and therefore, its lateral deformability (compared to its height) is highly increased. Consequently, a short column is much stiffer than other columns and accumulates higher shear stress that leads to diagonal cracking and failure.
  5. Infill Walls collapse: Infill walls that are connected with the building's framework may collapse. To prevent such failures, walls should be tightly jointed with the concrete beams and columns.
  6. Gable Frames failure: Gable frames are commonly used for large structures such as schools and cinema halls. They are prone to collapse and they do not present any residual strength.
  7. Reinforcing bars pull out: Reinforcing bars can be pulled out due to tensile stresses caused in the column when their anchor length inside the column is inadequate and they cannot fully reach their tensile strength.
  8. Articulated beams: Articulated beams are prone to sliding when large lateral stresses capable of exceeding frictional resistance, are applied.
  9. Sinking and tilting of the foundation: The foundation of a building may experience sinking or tilting during an earthquake. This is caused due to ground's response and is amplified in soft soils that experiences large deformations. In both cases, the superstructure will suffer critical damage which may lead to total collapse.

Source: Theconstructor.org

 

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