Application and Design of Segmental Precast Arches

The development of the arch was one of the most significant events in the history of structural design. Its value is apparent in the ability of the arch to transfer vertical loading into manageable compression loading. In the highway and industrial markets, arches have been developed as both precast and cast-in-place concrete structures used for bridges, tunnels, culverts and material containment igloos. A new technology called TechSpan^TM consists of segmental precast units forming a three-hinged arch structure. TechSpan utilizes the concept of a funicular curve. The term funicular is defined as "imitating a rope and its tension". This concept is used for the TechSpan design. This paper will discuss the analysis, design, and construction of TechSpan. The analysis involves use of a finite element soil-structural model, which allows flexibility in fitting various precast arch shapes to the needs of a project. Specific TechSpan projects will be discussed to demonstrate the relationship of analysis and design to the final construction of the arches.