This chapter deals with the methodology for diagnostic load testing. All aspects of diagnostic load testing that are shared with other load testing methods have been discussed in Part II. In this chapter, the particularities of diagnostic load testing of new and existing bridges are discussed. These elements include loading procedures, monitoring behavior during the test, reviewing test data, calibrating analytical models, and evaluating the test results.@en

A large number of existing bridges in Europe and North-America are reaching the end of their devised service life. Therefore, it is necessary to improve the methods of assessment for existing bridges. One method, suitable for existing reinforced concrete slab bridges, is the Modified Bond Model. This method, however, currently only takes the effect of torsion for loads close to the edge into account in a simplified manner. In this study, finite element models are created of a slabs with two supports, three concentrated (pre-stressing) loads and a distributed load, representing a truck wheel print. The load is varied along the longitu-dinal and transverse directions of the slab to find the bending moments (mx and my) and torsional moments (mxy). The results is an expression for the effect of torsion in slabs, which can be used with the Modified Bond Model for assessment and design of slab bridges@en