Estimation of Construction Year of Medium to Long Road Bridges in Zambia using Satellite Imagery

Abstract

<p>Using the age of the road bridges as one of the inputs, deterministic and probabilistic deterioration models are used to determine the deterioration rates and predict the future physical condition of these structures. This study attempts to estimate the year of construction of 27 road bridges in Zambia. The Technique assumes that the normalized difference water index 2 (NDWI_2) at the target bridge point (TBP) shows detectable differences before and after the construction of a road bridge. Landsat 5 Thematic Mapper in conjunction with Landsat 7 Enhanced Thematic Mapper Plus was used in the Google Earth Engine. Sequential t-test analysis of the regime shift method was applied with a cutoff length &#119897;&#119897;&#119897;&#119897; = 2 to &#119897;&#119897;&#119897;&#119897; = 12, and significance level &#120572;&#120572;&#120572;&#120572; = 0,05, to interpret the estimated year of construction from NDWI_2. The results confirm that it is possible to accurately estimate the year of construction of road bridges in Zambia using this method.</p>