On the key role of site inspections

Leonardo Todisco (Universidad Politécnica de Madrid)


The goals of inspections are basically:

  • to determine how is the condition of the Heritage;
  • to serve as a sound basis to undertake, if needed, new actions to ensure adequate performance of the structure (from the structural safety and users’ serviceability perspectives).

Principal inspections are merely visual. Neither samples are taken, nor lab tests are carried out; special access equipment might be necessary to inspect inaccessible points.

This activity should be carried out by engineers that:

  • know what to look at and how to interpret what they see;
  • have previous experience and can be supported by a catalogue of damages during inspection.

Sometimes, inspectors should also be able to understand why structures do not fall, or to detect malfunction of bearings and expansion joints and their consequences from a structural point of view and also functional problems that risk users life.

As general rule, the site inspection is based on the following procedure.
If it is the first inspection:

  • analysis of the information provided by the owner (old inventory or old non updated inspections, road or railway maps, original project or later works’ documentation);
  • GoogleEarth or StreetView available information;
  • Preparation of new forms.

If it is not the first inspection:

  • analysis of the last inspection (forms, photographs, notes, …);
  • preparation of updated forms.

In any case:

  • definition of points of access by car, on foot, by water, etc;
  • preparation of equipment (lantern, ladder, security equipment), camera, binoculars, crack meter, measuring tape or laser, catalogue of damages, etc;
  • preparation of the full list of necessary forms.

Once on site:

  • define the order of inspection throughout a general view;
  • inspection of the bottom part of the deck, starting at abutment 1, in zig-zag, examining all the previously defined components (abutment, piers, beams, slabs, arches or vaults from underneath);
  • inspection of bearing devices, drainage pipes and railing from outside the deck (or from piers and abutments);
  • inspection of the upper part: roadway, sidewalks, pavement, drainage, expansion joints, railing, etc;
  • inspection forms shall be fully filled in, explaining why some points were inaccessible, if they were.
  • enough number of photographs of good quality.

Once the visual inspection is completed:

  • collect the information required to evaluate the condition of the bridge;
  • inform the owner about the urgent situations that could endanger users;
  • undergo a control process by senior engineers;
  • repeat inspection if control was not successful.
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