Analysis of suspended bridges for isolated communities

Sammanfattning: Light suspended bridges are often used to connect villages or trail systems in geographical areas with lacking infrastructure and demanding topology. Different international non-profit organizations in collaboration with local promoters are building these bridges with the purpose of connecting isolated communities with health care and education. The design and construction of these bridges has by and large relied on engineering judgment and design conservatism coupled with past experiences of similar construction projects. An interest to engage in the designing of similar bridges has been shown from staff at the Division of Structural Engineering at the Faculty of Engineering of Lund University. This master thesis aims therefore to provide more sophisticated models of suspended bridges as material for future work. Suspended bridges are suitable to use for long spans, both due to low construction cost and to efficient material usage. They can also most often be built without advanced tools or machinery. The bridges studied in this thesis are intended for pedestrians and animals which result in a very slim design. Recommendations mainly from the development organization Helvetas will be compared to the Eurocode to investigate if these creates overly conservative designs. These comparisons will be made with both hand calculations, the finite element software Brigade/Plus and data from existing bridges. Vibrations and sways due to wind can be a major problem for light suspended bridges. Due to their small dead load in combination with a low lateral stiffness, the sways and vibrations can be very large in comparison with more common pedestrian bridges. This could lead to temporary inoperability or in worst case structural failure. With the models made in Brigade/Plus, wind effects can be analyzed and suitable measures or restrictions can be proposed.