Bridge infrastructures of most countries in the world are currently getting older and resource allocations are often limited. Hence, many researchers have pointed out that there is an urgent need to study their condition assessment to minimize bridge failures and reduce maintenance costs. They further express that present visual and deterministic assessment methods are not precise enough to count for many uncertainties of bridges. This book, therefore, introduces a condition assessment and maintenance strategy of bridges and bridge systems using reliability concept which is a branch of classical probability theory. The book includes an introduction to the reliability concept, reliability formulations of maintenance problems and case studies. This study should help bridge engineers and experts working on bridge maintenance and further academics and graduate students who are interested in bridge engineering and probabilistic approach.