Deformation Monitoring of Lotsane Bridge Using Geodetic Method

Civil engineering structures such as dams, bridges, tunnels, high rise buildings etc. are susceptible for deterioration over a period of time. Bridges in particular deteriorate after being constructed due to loading conditions, environmental changes, earth movement, material used during construction, age and widespread corrosion of steel. Bridge deformation monitoring is most important as it determines quantitative data, assesses the state of the structure and detects unsafe conditions at early stages and proposes necessary safety measures before can threaten the safety of vehicles, goods and human. Despite government’s efforts to construct roads and highways in most African countries, bridge deformation monitoring is not given priority and ultimately causes some bridges to collapse unexpectedly. In this paper we present a geodetic approach of bridge deformation monitoring of Lotsane bridge in Palapye, Botswana. The horizontal positions of reference and monitoring points were determined using Global Positioning System (GPS) while the height components were determined using precise leveling. The accuracy of the adjusted control points in x, y and z were 0.020m, 0.146m and 0.33m respectively. The final adjusted coordinates of the reference and monitoring points are presented and will be used for deformation monitoring of the bridge for the first epoch in 2020.