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An algorithm is developed to incorporate seismic capacity design philosophy in a computer program for the optimal design of single column circular reinforced concrete bridge piers for seismic loading. The program designs the circular column as a single degree of freedom system under the combined effect of axial and lateral seismic loads over a broad range of axial load ratio, column height and design displacement ductility capacity. Flexural, confinement and shear reinforcement requirements are then assessed for the entire range of parameters and cost calculations performed. For a given column height, design displacement ductility and axial load level, results indicate the existence of an optimal column diameter and ductility level. As the column diameter is reduced, cost savings are effected by reduced volume of concrete, but tend to be offset by P-Δ effects, increased longitudinal reinforcement for flexure, and increased transverse reinforcement for confinement and shear. Based on common trends, solutions are provided for the most economical range of the axial load ratio and design displacement ductility capacity for a given column height.

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The concept of pre-stressed concrete appeared in the year 1888. In this present engineering technology, durable and sustainable bridges play an important role for the socio-economic development of the nation. Owners and designers have long recognized the low initial cost, low maintenance needs and long-life expectancy of pre-stressed concrete bridges. This is reflected in the increasing market share of pre-stressed concrete, which has grown from zero in 1950 to more than 55 percent today. This growth continues very rapidly, not only for bridges in the short span range, but also for long spans with excessive length which, here therefore, has been nearly the exclusive domain of structural steel. Many bridge designers are surprised to learn that precast, pre-stressed concrete bridges are usually lower in first cost than all other types of bridges coupled with savings in maintenance, precast bridges offer maximum economy. The precast pre-stressed bridge system has offered two principal advantages: it is economical and it provides minimum downtime for construction.