“Computational Civil Engineering - "Intersections" International Journal

218 R. Scînteie, C. Ionescu2. ANALYSIS OF CONDITION INDEX I STA significant sample of 1795 condition reports is used. All reports were collectedafter last change in inspection regulations, so respecting the same rules. Forobtaining the correct results data must be consistent and the measurement systemcoherent. The total condition index I ST and the time from construction or lastrehabilitation/reconstruction were considered. The values are presented in Figure1.Figure 1. Values of the technical condition indexand preliminary regression curveReviewing available data one can see that they are on a very large time interval(111 years). On the available sample a polynomial regression analysis wasperformed for the entire period. The 6 th degree equation and the resulted curve arealso presented into Figure 1.This shape presents the inconveniences that make it useless because it does notsatisfy some physical considerations. The curve must be descendant for the entirelength (condition cannot improve by itself). It must also start from the maximalpossible value (at the beginning, the bridge should be in perfect condition, at leastin theory).Another aspect, that must be considered, is the very long period of time. It is veryprobable that this situation to be the result of lack of records for the moment of themoment of the reconstruction, rehabilitation or capital reparation. To eliminatepossible perturbations due to incompleteness, truncation of data was considered.Truncation reduces the applicability domain of the obtained equations and values,but one must not forget that the normal life length for a bridge is 50 years,according to regulations, and for some components it is even lower (25 years forthe deck). Also, according to present regulations, some works are mandatory to beperformed (maintenance, small repairing etc.) and which are not always recorded.