How to perform audit of old structures
There exist several types of public buildings with over 30 years lifespan. The stability of these buildings is decreased significantly owing to decay in materials.
On the basis of the yearly tests conducted on each public building, the weaker buildings having age over 30 years should be detected and the Assistant Executive Engineer level Officer of the related department should dispatch the list to the superior officer of the level.
Then, an inspection at the level of superintending Engineer/EE should be performed for all such building and an extensive structural audit should be carried out.
The related department should hand over the structural audit to an accredited Institution / agency and the details of which are provided below:
Usually, the Structural Audit should be performed with the following steps:
Step 1: The Architectural and Structural plans of the building are important. There should be detailed structural calculations along with assumptions for the structural design.
Step 2: When the Architectural plans and Structural plans do not exist, the similar should be arranged on the basis of site observations.
Step 3: A building should be examined thoroughly as follow :-
1. Any settlement in the building.
2. Cracks found in columns, beams and slabs.
3. Pictures of concrete disintegration and exposed steel reinforcements are useful.
4. Slight tapping with a hammer can disclose decay in concrete and wooden beams.
5. Erosion in reinforcement.
6. Status of Balconies – sagging, deflection, cracks.
7. Status of Architectural features.
8. Cracks in walls specifying swelling in R.C.C members or identification of erosion.
9. Leakages from terrace & Toilet blocks.
10. Leakages & dampness in walls which lead to cracks and corrosion.
11. Status of repairs & last repaired date.
12. What section of the structure was repaired?
13. Who was the Agency?
14. How much was incurred for repairs?
15. Are sanctioned Building plans available?
Step 4: Formulation of Audit Report:
Depending on the inspection on building, the Audit Report should be arranged.
Step 5: Tests Suggested:
It is vital that different types of tests are performed in the old buildings to get an idea about spreading of corrosion, distress and loss of strength in concrete & steel.
Step 6: Point out the major areas and repair them accordingly.