Comparison of Internal and External Prestressing for Typical Highway Bridges

The paper presents an analytical comparison of the amount of prestressing required for two similar bridges, one with internal and the other with external prestressing. This comparison shows that bridges with external prestressing can become economically competitive for large girder depths. The detrimental effect of the smaller stress in the prestressing steel at the ultimate limit state is more than compensated by the thinner webs made possible by the absence of the ducts.