Wooden Bridges: UNIDO's Prefabricated Modular System

At a glance..

The United a Nations Industrial Development Organization (UNIDO) has developed, through a project in Kenya financed by the United Nations Development Programme (UNDP), a unique bridge system suitable for developing countries with or without forest resources. The bridges are fully engineered; the cost is estimated to be less than one-half that of reinforced-concrete bridges.

The details..

'Wooden Bridges: UNIDO's Prefabricated Modular System' is a comprehensive guide on how to build fully-engineered timber structures that are ideal for use as secondary or access roads. This book details the unique bridge system developed by the United Nations Industrial Development Organization (UNIDO) through a project in Kenya financed by the United Nations Development Programme (UNDP). These wooden bridges can span up to 30 meters, carry up to 40 tonnes live load, and are estimated to cost less than one-half that of reinforced-concrete bridges.

The basic element of this bridge system is a triangular, three-meter long timber panel with mild-steel plate inned and spot-welded at the joints. Panels and steel tension chords completed at workshops await transport to the bridge site where they will be assembled into cross-braced trusses using various tripod, cable, and winch arrangements. Once abutments have been built these standardized components can be erected in just days.

This book outlines all aspects of constructing these wooden bridges from selecting appropriate species of wood based on strength requirements; preservative treatments such as copper-chrome-arsenic or creosote; galvanized nuts & bolts; welding rods; plug nails & bolts which should also be galvanized when used in tropical areas etc., right down to quality control measures necessary for safety during construction.

Overall 'Wooden Bridges: UNIDO's Prefabricated Modular System' offers an innovative solution towards providing safe transportation infrastructure across rivers even in developing countries without forest resources.