Rehabilitation and Strengthening of Steel Road Bridges

Experiences from rehabilitation of highway steel bridges are described. Fatigue cracks in orthotropic plates and in connections of cross beams and stiffeners, have been detected on three steel road bridges. The main cause of the damage is the more severe loading of bridges than was envisaged during their design due to increased traffic and higher axle loads. Other causes include inadmissible simplification of statical systems, inadequate fatigue design of structural details and fabrication defects. Repair of cracked members and strengthening of the bridges are discussed.