Bridge Inspection is of prime importance in any maintenance system since any sign of distress detected in early stages can be repair with minimum cost. All type of remedial and preventive maintenance including minor repair and replacement of bridge components should be planned at periodical interval without disturbing traffic on bridges.
According to Raina following categories of inspection are generally adopted for pre-stress concrete bridges.
Routine Bridge Inspection:-
In this type general inspection are undertaken frequently by highway maintenance engineers having practical knowledge of highway structure, through not necessarily expert in design, detailing and construction aspects. This type of inspection is required to identify minor deficiencies which could lead to accidents or maintenance problems or major repairs at a future date.pe of inspection is further
Such routine inspections are normally undertaken at intervals of one or two months.
Detailed Bridge Inspection
This type of inspection is further divided into general and major categories depending upon the frequency and intensity of inspection respectively.
General Bridge Inspection
This type of inspection is planned annually and it should cover all the structural elements of the bridges. It is mainly a visual inspection assisted by standard instrumental aids, invariably followed by a detailed written report.
Major bridge Inspection
This type of inspection is comprehensive involving detailed examination of all structural elements. This process may involve setting up of special access facilities (such as inspection platforms to examine set of deck slab and beam, articulation location and bearing at supports etc) when ever required depending upon the importance of structure, this is type of inspection is conducted at intervals of 2-3 years or may be at smaller intervals for importance (e.g. bridges located in coastal area, marine location and abnormal windzone)
Special Bridge Inspection
Emergency or special are planned under extraordinary loading situation such as earthquake high intensity/abnormal loading, floods, etc. these inspection should be exhausted including testing of structural elements (e.g. Non Destructive testing using ultrasonic pulse techniques to detect internal micro cracks and excessive deflections using dial gauges etc) the test results are examined in the light of structural analysis.
For this type of inspection, experiment bridges engineer should be involved in the investigation team. Special inspections are time such that the most critical evaluation of the performance of the structure is obtained, e.g. structural elements such as foundation, bridges parts and protective works are inspected before during and after floods.