TechSpan®

Optimized design procedure

TechSpan® precast arch culverts provide the ideal solution for short span bridging with precast concrete segments that offer rapid and safe installation, without the need for scaffolding. TechSpan® provides a long service life structure with superior seismic qualities and low maintenance requirements. Advanced design procedures and fabrication capabilities allow for the use of these precast arch structures in high-load applications usually not suitable for traditional systems. 

When designing the state-of-the-art design methods accurately define the radius of curvature of the arch to minimize tensile stresses and to ensure maximum strength. Our unique precasting methods produce structures that can handle any geometric design or clearance box. Our economical way of using concrete and reinforcing steel provides maximum safety at the lowest possible cost with long service life.

RECo engineers conduct a custom finite element model (FEM) analysis design to accurately define the optimum radius of curvature for an arch based on the project specific span length, soil coverage and construction sequencing requirements. This design produces the most efficient and economical sections. Even though the TechSpan® solution is sophisticated in terms of design, it is simple for planners and builders to incorporate into their projects. These structures are designed to accommodate high fills, heavy live loads, as well as alternating loading conditions imposed during both installation and in service conditions.

Optimized manufacturing processes

We use our unique flexible formwork and quality-controlled casting process to produce finished elements that comply with a wide variety of geometric and material quality specifications.

Our design and material supply package often includes materials required to construct the necessary retaining structures for wing walls and head walls, and also other precast solutions including footings, copings, and barriers.

Optimized installation procedures

Speed of installation of TechSpan® precast concrete arches greatly reduces the overall construction costs. Requiring only a narrow footprint to build, TechSpan® installation is simple, rapid and efficient requiring only a small work crew, light tools and conventional equipment. Erection rates of 10 to 20 linear meters of TechSpan® arch per day are easily possible with only a single crane with an operator and a small work crew. 

The TechSpan® precast concrete tunnels solution eliminates the need for intensive onsite formwork, scaffolding, joints, or bearings. Installation on existing roadways, railways, waterways, and conveyance systems is possible without disruption to the ongoing activity. The proof of the effectiveness of TechSpan® is a successful experience: since 1989 over 1500 installations of custom designed TechSpan® structures have been placed in service for highways, railroads, industry, and other uses in the world.

TechSpan® precast arch culverts construction starts with the installation of cast-in-place or precast footings on both sides. The arch units are set along the footing keyway in a staggered pattern. After the third unit is set, the arches are self-supported during the remainder of construction. Geotextile or geomembrane is applied to the joints as designed. The crown beam is cast along the top of the arch. MSE headwalls or wing walls are then installed as design guidelines and specifications. 

We have created precast collars specially for TechSpan® and these collars cover the outer edge of arches creating a uniform aesthetic look.

Advantages of TechSpan® precast concrete arches

• Finite element model design provides for the development of the optimal shape based on loading conditions.
• Precast segmental arch units simplify shipping, delivery and installation.
• Self-supporting unit design and installation procedure minimizes heavy equipment usage and bracing requirements.
• Capable of supporting large surcharges in excess of 30 meters.