Janson's Truss Bridge system (PSB) is a bridge intended for permanent use and was particularly developed for rural areas where infrastructure and transport facilities are limited, for emergencies (floods, earthquakes) and for peacekeeping operations.
The external appearance, combined with the high quality structure, makes this bridge system an increasingly popular option for permanent solutions in developing countries.
The bridge is practical in design, requiring only a limited number of components. The components required can be carried by light vehicles, be handled manually and are fully containerisable. Complete erection by hand, without the availability of cranes, is an important feature of the Janson Truss Bridge system. Assembly of the bridge may be carried out using unskilled labour under the supervision of an experienced engineer. The bridge can be erected using the standard cantilever launch methods or lifted using a crane. Single or multi-span bridges can be assembled using standard equipment.
Janson's Truss Bridge is a modular system with longitudinal trusses built up using standard interchangeable components in modular lengths (bays) of 4.0 or 6.0 metres.
All components are bolted together using standard fasteners. During manufacturing, welding is kept to a minimum ensuring a high fatigue life. The trusses can be configured in different configurations to form girders whose strength is tailored to suit the span and loading of the individual bridge.
The transoms carrying the traffic decks are positioned between the longitudinal trusses and are available in various widths, in increments of 0.25 metres. Standard deck units are available in different capacity types and are bolted directly to the transoms.