Four types of cracks developed in reinforced concrete column are diagonal cracks, horizontal cracks, splitting cracks, corrosion cracks. The causes of cracks in columns can be incorrect design, faulty construction or overloading, corrosion of reinforcement, isolated settlement of foundations, creep and shrinkage.
Cracking in reinforced concrete column is a serious problem and it may lead to the loss of strength, stability, durability, and detrimentally influence aesthetics. Therefore, it is required to investigate different types of cracks that may initiate in columns in order to consider suitable means to restrict them.
Types of Cracks in Concrete Columns
1. Diagonal Cracks
Diagonal cracks in reinforced concrete columns develops and encompass the entire face of column anywhere along its height. The main cause of diagonal cracks in concrete columns is inadequate load carrying capacity of the columns; insufficient cross-section and inadequate reinforcement steel. Diagonal Cracks would influence structural soundness and hence it needs to be dealt with properly.
Fig. 1: Diagonal Cracks in Concrete Column
2. Horizontal Cracks
Horizontal crack in reinforced concrete column is observed to initiate mostly at the beam-column junction, and on column face where tensile stress is large. Columns with in adequate moment resistance capacity, insufficient reinforcements, or disposition of installed reinforcement are prone to horizontal cracking; due the effect of shear force and direct load and uniaxial bending.
Finally, horizontal cracks substantially reduce the shear strength of the column leading to a greatly increased risk of failure. So, it is required to be tackled as soon as possible.
Fig. 2: Horizontal Cracks in Concrete Column
3. Splitting Cracks
Splitting cracks in reinforced concrete column are short parallel vertical cracks with non-uniform width. Columns with Insufficient steel reinforcement, and low concrete quality are susceptible to experience such types of cracks. Splitting cracks in concrete columns initiated as a result of reaching its maximum load carrying capacity.
The ultimate Load carrying capacity of the column surpassed when concrete cross section is inadequate or reinforcement ratio is insufficient or combination thereof.
Fig. 3: Splitting Cracks in Concrete Column
4. Corrosion Cracks
Corrosion cracks in concrete columns are developed along the line of reinforcements. This type of cracks is commonly uniform in width and widen as the column is ageing.
Possible reinforcement corrosion and inadequate bond between concrete and steel bars are the cause of corrosion reinforcement in concrete columns. If such type of cracks is not tackled the corrosion of reinforcement would accelerate considerably.
Fig. 4: Corrosion or Bond Cracks in Concrete Column
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