Precast Prestressed Long‐Span Bridges

Precast prestressed concrete can be a strong, durable, and aesthetically pleasing material for use in long‐span bridges. If erected using the proper techniques and care, such bridges meet society's demands very well. Specifically, prestressed concrete allows for stronger bridges at lower construction and maintenance costs. With this objective as motivation, prestressed concrete design and construction has rapidly spread through the United States. Of the construction techniques available, two methods dominate: segmental cantilever construction and cable‐stayed construction. These two techniques are the primary focus herein. In addition to the construction technique, the erection method and section type must be considered in the design process. In the United States, I‐sections, box sections, T‐sections, hollow‐core, and channel sections are commonly used for highway bridge design. Care must also be taken to insure that a prestressed concrete bridge is an economical one when compared to reinforced concrete and steel plate girder bridges. Ultimately, it is the job of the engineer to consider each facet of a design, so that, in addition to performing as intended, the structure is safe and economical.