Case Studies of Different Types of Failures in Reinforced Concrete Buildings:
Case 1: Failure of RCC Column Due to Corrosion of Reinforcement
Observation month : October, 2015 Site condition : Good quality soil, 1 km from sea coast Observation : Excessive rust in dowel rebars in columnCase 2: Failure of Building Due to Improper transfer of load
Observation month : November, 2015 Site condition : Good quality soil, No engineer consulted Observation : Poor workmanship (Improper transfer of load due to poor centering) Investigation : The centering was done by a normal mason and proper techniques were not used. Also due to congestion of rebars at beam column junction the mason avoids compaction which leads to honeycombing. Precaution to be taken : Centering has to be done by training centering masons and site supervision by engineers is necessary during foundation centering, casting and casting at every slab. Compaction needs to be done homogeneously at every stage of constructionCase 3: Failure of Reinforced Concrete Structure due to Poor concrete mix and water quality
Observation month : August, 2015 Site condition : Good quality soil, design by engineer ignored during construction Observation : Poor concrete mix and water quality Investigation : The water quality was not checked before use. After testing it was found that the concrete did not achieve the desired strength of 20 MPa due to poor quality of concrete mix and water. Precaution to be taken : The quality of all building material (cement, stone chips, sand and water) needs to be checked before mixing. Also the pH of water should be more than 6, i.e. not acidic. Any deviation from design should be approved by the structural engineer.Case 4: Failure of RCC Structure due to use of Beach Sand in Construction
Observation month : August, 2015 Site condition : Good quality soil, 1 km from sea coast Observation : Deep cracks in ground floor columns and concrete chipping all over the building Investigation : Beach sand (high salinity) was used for construction. Also ground water (without chemical testing done) was used in concrete. Precaution to be taken : The quality of building materials should follow the quality norm as mentioned in IS 456: 2008 Section 2. The detail is given in the chart.Fig: Deep cracks formed in RCC Column, Rebar gets exposed