Abstract
Inspection and repairing of slabs of highway bridges suffering from deterioration are the most important tasks among road management works. In Japan, many road authorities have their own codes of practice for the inspection. However, criteria for the deterioration in these codes are set up empirically by visual inspection of some factors such as crack density, crack width or crack pattern. Therefore, it is required to establish a rational criterion. The authors have judged deflection of slabs to be the most useful index for deterioration of the slabs and proposed a rational evaluation method by the deflections. Furthermore, by finding a good correlation between the deflections of the slabs and the crack densities on the bottom surfaces of the slabs, a useful rating equation by the crack density is also proposed.
