DYNAMIC ASSESSMENT OF BRIDGE LOAD-CARRYING CAPACITIES .1.

A one-fifth model reinforced-concrete beam-slab bridge deck was tested to destruction, and the vibrational response to ambient excitation wa s measured at different stages of cracking and spalling. Observations showed that the neutral axis remained close to the lower flange of the T-beam throughout the loading range. A method capable of assessing th e load-carrying capacity as well as the structural condition of a T-be am slab bridge deck has been developed. This requires prior informatio n on the geometric dimensions and fundamental modal frequency of the s tructure, and two methods are discussed and proposed for assessment. T he results of a parametric study of the effect of different boundary c onditions on the fundamental modal frequency are presented in this pap er. Different potential sources of error in this process are discussed and the manner of implementing the method is presented.