It is evident that leaking from a leak drainage system negatively affects the development of corrosion processes on affected elements of the load-bearing structure. On the examined surfaces occurred due to leaking a significant increase of corrosion losses. The biggest differences in the experimentally measured corrosion characteristics after one year of exposure have been observed at the inner web of the bridge in Ostrava (values of annual corrosion losses on surface affected by leaking are 4.8 times higher when compared with the same type surface with favorable patina development, the average thickness of corrosion products on surface affected by leaking is 3.8 times higher). The minimum differences were identified on the bridge in Frydek-Mistek where due to leaking from a leak bridge expansion joint
This formula was determined using linear regression analysis. The relation between both quantities can be used for monitoring of patina development. The relation is valid only for the first year of surface exposure. In the longer term there is a stabilization of the thickness of corrosion products, corrosion losses, however, continue to increase. the blue points represent the series of observations, the red dotted line represents the linear regression line. The green curve (upper bound) and violet curve (lower bound) define the prediction interval with a probability of 95 %. The area between orange lines represents the 95% range of confidence interval. Measurement of corrosion products thickness using the portable thickness gauge are easily and quickly feasible and can serve as a simple and relatively fitting procedure to determine real values of the initial corrosion rates of weathering steels. The established dependence between both quantities can thus be used as one of the evaluation criteria of patina development on weathering steel structures.