How it Works

TechSpan® Tunnels

 Shape Calculator for TechSpan® precast arch solutions

TechSpan® is a three pin, two piece precast concrete arch that enables the designer to create the most structurally efficient custom made shape to suit any particular clearance or loading condition.   Our precast arch technology, known as TechSpan®, is a result of decades of research, development and experience. Building on this wealth of experience, we present a platform dedicated to help you find your bespoke precast concrete arch solution: Visit to download our catalogue and create your customized arch profile. 


TechSpan® Arch SystemInstalling TechSpan® Arch Panels


TechSpan® - Arch DesignTechSpan® - How it Works

The genius of a TechSpan® arch is best understood when considering the funicular curve. The term funicular is defined as “imitating a rope and its tension”. As ‘rope’ cannot support compression or bending load, it takes its entire load in tension. However if the “rope” could be turned into concrete and then inverted, it will create the most structurally efficient profile and would then be able to support its load in pure compression.


Funicular curves have infinite variations, but in each one the bending moment and tensile stresses at any point are theoretically zero for any given set of load conditions. Techspan® arch design follows this same mathematical approach to create a custom made structurally efficient profile to suit each unique set of geometry and loading conditions.

TechSpan® is always designed for the most economical use of concrete and reinforcing steel to minimise the quantity of materials needed for manufacturing and transport.


Added advantages include the reduction of carbon emissions and transportation costs, and an increase in the ease/speed of erection, durability, and design life.

TechSpan® Roadway Tunnel

One of the main advantages of Techspan® is the ease and rapid speed of construction. Once the initial four units are in place, only one crane is needed from thereon as each arch unit is supported by the arch unit previously placed. A concrete crown beam is then installed at the top of the arch structure, effectively locking the structure together as a robust concrete tunnel.

TechSpan® tunnels can be rapidly installed without disturbance to live traffic or rail corridors.

Installing TechSpan® Arch Panels for a Railway TunnelInstalling TechSpan® Arch Panels