Handbook for Bridge Inspections - TSP2

This check may also prove necessary during Special Inspections
should there be any suspicion of screws having lost theirorigina l
tension.
Equipment
• Torque wrench
Purpose
Procedures
Equipment
7.4.2 Checking Rivets and Screws
To check whether rivets and/or screws are loose or have possibly
dropped out of place.
Loose screws or ri vets can cause cracks to appear in the surface
treatment at the cross-over point between screw/rivet head and the
basic material. By lightl y tapping on one side oflherivet wi th a
hammer whi le placing one's finger on the opposite side of the ri vet
at the cross-over point one can feel whether the ri vet is loose.
• Magnifying glass
• Torch
• Hammer
Figure 7.4-/: Checking a RiI'el
Equipment
Purpose
Procedures
Equi pment/Competence
7.4.3 Checking Welds
To carry out visual check for fau lts in the welding or whether
damage has been caused to the welding.
If material defects are suspected, X-ray or ultrasound checks
should be carried out in addition - see points 7.4.4 and 7.4.5.
• Magni fy ingglass
• Torch
• Tool for measuring the width of cracks
7.4.4 X-ray Check
To carry out X-ray inspections of welds and other steel elements to
check for material defects.
The X-ray fi lm should be used to document the results.
The inspection should be undertaken by a pe rson with the relevant
training and the necessary speciali st equipment.
Purpose
Procedures
7.4.5 Ultrasound Check
To ascertain with the use of ultrasound equipment whether there
are material defects in welds, or cracks in screws or ri vets.
Reference is made to Procedure No. 87. 1835
The measurements should be taken using a test sensor whi ch transmits
and receives ultrasound waves which actually work on a frequency
beyond the that of human hearing (approx. 16,000 Hz).