Assessment and analysis of the condition of bridges

The Road Administration and larger municipalities use the BMS (Bridge Management System) methodology to manage the road facilities they own (bridges and viaducts), which is suitable for network-level analysis of bridges. The methodology includes a visual inspection of facilities and data analysis with BMS software.

As a rule, bridge inspections are carried out in the period from April to October, when the weather conditions are suitable and the high water has receded. During the inspection, the following is carried out:

• control measurements of the dimensions of bridges (if necessary)
• assessment of element damage extent and element condition levels
• photography of bridge elements – side views, top views and defects

During inspections, bridges are assessed by element (beams, columns, handrails, etc.). Each unit of the bridge element is given a grade according to its condition level (on a 4-point scale, where condition 1 indicates the condition of the element and condition 4 the worst condition).

Modern bridge fragment: Vasco da Gama Bridge (Ponte Vasco da Gama), Lisbon

The BMS methodology is mainly intended for network-level analysis of bridges, and less attention has been paid to the possibilities of detailed analysis of individual bridges, i.e. for economic analyzes – whether to repair, rebuild or replace the bridge.

The Condition Index (SI) is used to compare the condition of different bridges, which shows the physical condition of the bridge on a scale of 0-100% (the index does not take into account the limitations of the dimensions and load capacity of the bridge). The SI is calculated based on the condition data of the elements collected during the bridge inspection. According to SI, it is possible to monitor the change in the condition of the entire bridge network in different years and to compare the condition of different bridges.