There are four types of inspection for reinforced concrete structure namely: inventory, routine, detailed, and special inspections. Inventory inspection is carried out when a building becomes ready to be delivered, and it provides assurance that the concrete structure is structurally safe and fit for its designed use. So, it may identify actual and potential sources of trouble at the earliest possible stage.
Routine and detailed inspection is performed to record systematically and periodically the state of the structure. This enables one to know the time when defects occurred and to identify any significant structural changes like deformation and loss of camber. The outcomes detailed inspection can be used to specify suitable maintenance and repair technique to tackle the identified defects or deterioration.
The findings of special inspections, which is conducted when a structure suffered unusual loads such as in the case of earthquake, would provide necessary information on which decision would be made for carrying repairs, strengthening, replacement in the concrete structure.
Inspection need to be performed by engineers equipped with sufficient professional expertise and experience otherwise the results of the work may lead to collapse of buildings and more severely the loss of life. To sum up, inspection is the first step towards any maintenance programme.
Types of Reinforced Concrete Structure Inspections
1. Inventory Inspection
Inventory inspection is carried out when the construction of a structure is ended and it becomes ready to be delivered, when a change in configuration is applied, or when a structure is ready back to service after a major intervention. The results of inventory inspection is used as a baseline for other inspections that may be conducted in the future.
2. Routine Inspection
Routine inspection is the periodic and quick examination of the general conditions of concrete structure which is carried out by competent and qualified engineers.
Each inspection should be recorded accurately and properly. Primarily, the inspector carries out visual assessment, and may employ simple instrumental aids to specify the condition of the concrete structure.
The principal purpose of routine inspection is to discover all indications of deterioration or damage such as texture or color of concrete, exudation, cracks, spalling, delamination, leaching, rust streaks, deformation, loss of camber, and salt build-up.
3. Detailed Inspection
Detailed or comprehensive inspection is a more intensive, time consuming, and thorough inspection than the routine inspection. It is performed between certain number of routine inspection and is scheduled based on the importance of the structure.
The inspector should closely examine all the details of the structure such as structural, mechanical, environmental, durability, material, and electrical details.
If necessary, specialized tools, such as hammer sound testing or any other non-destructive test, would be used to accurately determine the state of the structure. The detailed inspection should be carried out by specially trained engineers who can plan comprehensive repairs.
4. Special Inspection
Special inspection of concrete structures is done in special conditions after the occurrence of unusual events. So, special inspection is need-based and is carried out as and when required. Special inspection may require supplementary testing and structural analysis and may require detailed involvement of a structural engineer.
The outcomes of this type of inspection should be enough to make a proper decision about the next action to be undertaken for the structure under considerations. Conditions in which special inspection is required may include but not limited to the following circumstances:
- When signs of weaknesses discovered during routine or detailed inspection or by any other observation.
- When the structure loading is to be increased due to revised or increased loading standard.
- Distressed concrete structures.
- When subsidence occurs in areas of mineral or coal extraction.
- When settlement of foundation takes place.
- When seismic activity takes place.
- In case of exceptional events for example flood, storm, fire, accidents, etc.