ABSTRACT
Site specific traffic loads and dynamic amplifications are used in bridge assessment to eliminate built-in conservatism in design codes. The conservatism while acceptable at design stage can lead to costly measures of repairs, upgrades or traffic restrictions when applied to existing structures. Dynamic amplification factors obtained from an instrumented span of the Olifants river bridge on South African heavy-haul line are compared with factors provided for in design codes. The strain based dynamic amplifications factors up to 10% of static value are obtained for the operating speeds on South African Iron Ore line which are much higher than those provided for in the South African Railway Services loading code.
