The Use of Multi-Criteria Parameters for Bridge Maintenance Prioritization and Maintenance Categorization Options in Tanzania

Abstract

A bridge is a structure across physical obstacles like valleys, rivers, seas, oceans, lakes, roads and railways. Its components get damaged when exposed to harsh conditions resulting from various causes which reduce its lifetime. Maintenance is necessary to prolong its remaining service life once they get damaged. Successful maintenance depends on various factors including the availability of funds and the effectiveness of condition assessment and other damaging factors. Many developing countries face a scarcity of financial resources to restore the functions of bridges at network levels. In order to have a better planning of the financial resources, it is important to devise a methodology for prioritization of bridge maintenance at the network level. This research used parameter ratings to determine the Bridge Prioritization Index (BPI) derived from selected parameters affecting bridge performance. The parameters considered for this study are bridge defects, earthquakes, traffic actions and scouring potential. The prioritization indices were determined from four bridges which are Kikwete, Mvomero, Unkuku and Nyahua. The bridge ratings from bridge condition indices were determined to be 2 for Unkuku and Mvomero bridges and 1 for Kikwete and Nyahua bridges. Scour ratings from scour indices were determined to be 4 for Unkuku, Nyahua and Mvomero bridges and 3 for the Kikwete bridge. Seismic ratings from seismic indices were determined to be 1 for all four bridges and Traffic ratings from traffic indices were determined to be 3 for Unkuku and Nyahua bridges and 2 for Mvomero and Kikwete bridges. Bridge prioritization indices (BPI) determined indicate that Unkuku bridge has higher priorities in maintenance than other bridges having a BPI of 2.19, followed by Mvomero with a BPI of 2.08, Nyahua bridge with a BPI of 1.67 and lastly the Kikwete bridge with a BPI of 1.41. Based on the obtained BPI, the maintenance action required was proposed to be preventive maintenance for Unkuku, Nyahua and Mvomero bridges and routine maintenance for the Kikwete bridge. Further studies are proposed to include the earthquake amplitude in bridge maintenance prioritization.