0

Bridge inspection:

Inspection and readiness of an Inventory are as a matter of first importance model of any maintenance work. Various inspection types are there for bridge rehabilitation work. Bridge Inspection is significant for checking the physical condition and for the arranging of any maintenance exercises. Without legitimate inspection and assortment of precise information, assessment of the requirements of the structures and arranging of maintenance exercises will be ineffectual. Customary inspection of the bridge, approach viaducts, retaining walls, roads and others are significant structures are fundamental for the safety and serviceability of the equivalent after development. During the inspection, it ought to be the point of the Inspection Engineer to decide the reason for the deterioration.

Inspection of existing structure
inspection-of-existing-structure

Bridge Inspection Objectives:

The design lifetime of bridge or flyover is around hundred years and needs to provide service for enormous traffic volume, in this way, keeping up serviceability and subsequently retaining its level of reliability during the lifetime deserves high priority from techno-economic considerations. Absence of ordinary maintenance of the Bridge or Flyover may prompt deterioration preferably prior over its designed life. Concrete structures are exposed to many types of environmental influence; in this way, it is of fundamental significance to prevent their deterioration. The aftereffects all things considered and maintenance work are to be precisely and fully recorded; including zero defects with the goal that a complete history is promptly accessible for all occasions.

Inspection Engineer Duty:

Every part of works shall be inspected in a series either by a) visual inspection or by b) mechanical assessment or both as per the need and availability of equipment/instruments and accessibility. The visual inspection has more weightage as it is likely to assess the overall integrity and structural safety within this. Hence, careful visual inspection is a pre-requisite for proper maintenance as this can explain much hidden severe deterioration. Various types of inspection, persons engaged and their duties are mentioned below to elaborate the inspection exercises:

  • To provide a promise that the structure is structurally safe and fit for its operation as per the design specification. This associate to the constant deterioration of the bridge with time or to an accidental incident such as impact, flood or overloading.
  • Recognizing potential causes of trouble at the earliest possible stage and propose corrective and preventive measures.
  • To record symmetrically and principally the vital information on which decision can be taken for taking out maintenance, that is repairs, strengthening or replacement of the structure.
  • Providing feed-back data to designers and managers of bridges on those points which are likely to arise maintenance problems and to which required attention is best given during design and construction stages.  

Bridge inspection Tools:

Clip Boards

Torchlight

Straight edge

Camera

Chalks and markers

Screwdrivers

Plump bob,

Binocular

Thermometer

Helmet

Spirit level

Pliers

Inspection mirror

Safety belt

Magnifying Glass

Torque wrench

Pocket knife

Scrapper and paper

Chipping hammer

Feeler gauge

Wire brush

Crack meter

Chisel

Calliper

Note: Tools mentioned above should generally be adequate for different types of Inspection, but in addition, NDT tests may be required in case of Special Inspection.

Inspection Types:

Based on the importance of structure and contribution to the whole project as well as the safety of traffic movement, the whole inspection procedure shall be divided into three categories. Following are the inspection types

                (a) Routine Inspection 

                (b) Principal Inspection 

                (c) Special Inspection 

Routine Inspection of Bridge:

The routine inspection will be carried out by Inspector once in two months. Primarily, the routine inspection may be carried out once in two months for first three years and after that routine inspection for works may be carried out once in three months as per the number of distress happened and approval of higher authorities. The report of the routine inspection will initially depend on the visual examination of the structure using conventional methods and standard inspection tools. Under routine inspection, the deficiencies which may lead to an accident or cause huge maintenance and repair cost, if not attended, would be reported.

Report: 

Observations of Routine Inspection should be recorded in an Inspection Register in a standard format to be developed by the organization. 

Follow up Action:

If any important or major distress noticed during a routine inspection, the matter should be reported to the senior level engineer and detailed inspection should be carried out.

Principal Inspection:

The Principal inspection would involve a more intensive and detailed examination of elements of the structure. The first inspection shall be carried out just after completion of the project. After that, the principal inspection will be carried out at six months interval for the first two years and once in a year for the remaining period or as decided by the Chief Maintenance Manager. It will be primarily close visual assessment supplemented by standard instrumented aids. The inspection shall be carried out by Executive Maintenance Manager or Specialist Agencies along with Inspector/ Maintenance Manager against a comprehensive checklist. The frequency of the Principal inspections will be reduced in case routine inspection reveals any distress. The Principal inspection shall be stressed, especially in the following:

Report:

Detailed Inspection: Reports of detailed inspection should be accurate and factual. Where there is any uncertainty about the condition of any components or the structure as a whole, it should be clearly stated in the report. Should be sufficiently complete to accurately assess the structural load carrying capacity or with other related information based on which detailed analysis of its capacity may be carried out. It should also provide sufficient information for programming of any maintenance or other work if required.

Follow up Action:

As per the findings of the detailed inspection and test reports, the decision should be taken regarding the further line of action in consultation with the design consultants, if necessary, including instructions as to whether a special inspection is called for.

Special Inspection:

This shall be undertaken in the event of unusual occurrences such as accidents, passages of unusually heavy loads, severe earthquakes, flood and major weaknesses noticed during routine or principal inspections, unusual settlement of foundations and substantial changes of the traffic pattern. When other bridges of a similar design and constructed almost at the same time are showing some distresses the bridge in question shall be subjected to special inspections. Such inspections shall require a good deal of supplementary testing and also the input of the design organizations or experts if necessary. This inspection shall be carried out as when required.

Report: 

Observations of Special inspection in case of distresses should be recorded on a separate register called “Special Inspection Register”. As regards the Special Inspections, which are to be done immediately in case of accidents and severe earthquakes of intensity more than that for which it has been designed, etc., observations should be recorded as a separate note.

Follow up Action:

Observations of Special inspection in case of distresses should be recorded on a separate register called “Special Inspection Register”. As regards the Special Inspections, which are to be done immediately in case of accidents and severe earthquakes of intensity more than that for which it has been designed, etc., observations should be recorded as a separate note.

Bridge Inspection Photographs
Bridge-Inspection

Locations to be Specially Looked for Defects:

  • General condition
  • The bottom slab in box girder
  • Drainage spouts
  • Top and bottom of the deck slab
  • Box girder webs
  • Joints in segmental construction
  • Support point of bearings
  • Girder Diaphragms
  • Expansion joints
  • Top and bottom flange of the girder
  • Junction of girders and diaphragm
  • Elastomeric/POT-PTFE Bearings

Maintenance of structures generally gets neglected because of a misconception that once constructed it does not need any substantial maintenance particularly in the first couple of decades after construction, but concrete is a heterogeneous material, and its durability depends mainly on quality control during production, workmanship and condition of exposure. So, To keep the structure in good condition, it has to be inspected regularly and maintained in a well-planned manner.

0
Summary
Inspection Types for Structure - Objectives and Guidelines
Article Name
Inspection Types for Structure - Objectives and Guidelines
Description
Inspection and preparation of an Inventory is the first and foremost criterion of any maintenance work. Bridge Inspection is important for checking the physical condition and for the planning of any maintenance activities. Without proper inspection and collection of accurate data, assessment of the conditions of the structures and planning of maintenance activities shall be ineffective.
Author
Publisher Name
Construction Civil
Publisher Logo

WhiteHelmet

ConstructionCivil is a learning platform for all the Civil Engineers and Civil Engineering Students throughout the world. I have started this Website to educate and keep people notified by forming a trusted source of knowledge, everything related to Civil/Construction Engineering.
Subscribe
Notify of
guest
0 Comments
Inline Feedbacks
View all comments