ABSTRACT
The load testing of bridges can be of enormous benefit to engineers in aiding
their understanding of the behaviour of bridges at both the serviceability
and the ultimate limit states under the action of live loads. After a bridge has
been constructed it is quite usual to carry out a live load test to measure the
response of the structure by the use of appropriate strain and displacement
devices. This will confirm (or otherwise) the assumptions made in the orig-
inal analysis regarding load distribution, stress levels and deflections. In
France and Switzerland it is common practice to load test all new bridges with
a static load (DLþ LL) equivalent to 80% of the maximum design life bending moments (Markey, 1991; Favre, Hassan, & Markey, 1992). A good example of
this was the recent test carried out on the new Pont de Normandie cable-
stayed bridge at Le Havre (New Civil Engineer, 1995) when 80 lorries
weighing 15 tonnes each were positioned on the deck and on the approach
spans. The measured midspan deflection values were close to those predicted.