Inspection, rating and other data are extracted from the National Bridge Inventory to trace the market growth and assess the performance of prestressed concrete bridges built during the last 40 years. Comparisons are made among prestressed concrete, reinforced concrete, steel and timber bridges based on structure age, span length, average daily traffic and "structural deficiency" as defined by the Federal Highway Administration. Since their introduction in 1950, prestressed concrete bridges have captured 50 percent of the bridge market. The two most common prestressed concrete bridge types, stringer and multiple box, dominate most regions of the United States. Early prestressed concrete bridges are still in service 40 years later and, based on the NBI data, generally are performing very well. At comparable ages and spans, smaller percentages of prestressed concrete bridges are classified "structurally deficient" than steel or timber bridges. The prestressed concrete advantage is especially noticeable for short spans and for low volume roads, a category in which significant numbers of new steel and timber bridges are rated structurally deficient. The rate at which structural deficiency percentages increase with age also is lower for prestressed concrete than for steel or timber. The NBI data support the excellent reputation that prestressed concrete as acquired among bridge owners.
