4.0 UNDERTAKING THE INSPECTION

In order that the information provided by the inspection is of adequate quality the inspection must be detailed and thorough, and carried out in a systematic way. At each site the following routine should be carried out:-

• Establish safe working conditions
• Undertake general appraisal of the site
• Carry out detailed inspection

These will now be described in more detail.

4.1 Safety

On arrival at the site vehicles should be parked in a safe place - preferably off the road - and the signboards put in place. These should be sufficiently far back from the structure (say 100 metres) to give approaching traffic adequate warning that there are people working on the bridge.

In some cases there may be a need to establish positive traffic control before the inspection can be safely undertaken - for instance if working on ladders on a truss bridge deck.

Access to difficult areas should not be attempted without appropriate equipment. Please refer to Part 2: Procedures for the Inspection and Maintenance of Bridges for additional advice on safety.

4.2 General appraisal of site

Before starting the detailed inspection of the bridge components, the engineer should first check that it is the right structure. It is surprisingly easy to confuse similar looking bridges with one another.

Having established the identity of the bridge the details from the bridge inventory record should be checked. This will help in understanding the structural principles of the bridge - particularly in relation to how movement is accommodated - and will assist in completing the rest of the inspection forms. Some guidance on the different types of bridges is given in Appendix A.

It is essential at this stage to make sure of the orientation of the bridge, identify which way is north, and the direction of flow of the river.

4.3 The detailed inspection

After completing this preparatory work the detailed inspection of the bridge can start. Each part of the bridge must be inspected thoroughly and its condition recorded using the appropriate inspection report forms which are included in Appendix C. These provide a check list of items to be inspected as well as a standard method of reporting the findings. The condition rating system is explained in Section 5.2 and guidance on some of the defects to be found in bridges is given in Appendix B.

It is essential to fill in the forms at the time of inspection. They should never be filled in afterwards. Additional notes or sketches may be made on the backs of the forms if required.

Sketches should be made to illustrate the location of any defects which are identified. These sketches will be freehand but should be roughly to scale.

Although the inspection is essentially a visual exercise, it may sometimes be useful to take measurements. Examples of these are measurements of crack widths in concrete and of out-of-plumb dimensions in columns.

Occasionally it can be useful to collect samples of items such as broken concrete, corrosion products or paint flakes.

The condition of any previous maintenance or repair work should be carefully examined and reported. This is important as it provides guidance on the most effective materials and techniques to be used for future repair work.

It is important to record the weather conditions at the time of the inspection. Some defects such as leaking joints or defective drainage are much easier to identify in wet weather, whereas narrow cracks in most materials are easier to see when it is dry.

Photographs should be taken to supplement the completed forms as they provide a useful permanent record of the inspector’s observations. A general view will help to confirm the identity of the structure, and specific views should be taken of major defects.

Where the inspector identifies the need for maintenance or repair work to be carried out it is useful to make an estimate of the approximate quantity of work involved - for instance the volume of gabions required for abutment protection work - so that budget cost estimates can be prepared.

For Principal and Special Inspections the inspection and reporting format are increasingly detailed. Ratings are attributed to each element on the structure and reporting is comprehensive.