Aerodynamic stability of slender suspension bridges
This thesis studies the aerodynamic stability of a proposed suspension bridge crossing the Sognefjord. Such a bridge will require a main span of approximately 3700 m, almost double the span length of the current record holder. For such a long span and slender suspension bridge its aerodynamic properties are highly important.
A comparison of the aerodynamic stability limits using three different configurations of a so-called vented or dual box girder has been done. The only difference in each configuration is the center-to-center distance between the individual box girders. The design of the individual girders and the cable system is kept constant.
A modal approach to solving the equation of motion has been employed where the eigenfrequencies and eigenmodes have been computed using a computer program called ALVSAT. The numerical calculations of stability limits as well as dynamic response have been done using self-written MATLAB scripts based on well-established theory of bridge aerodynamics. Aerodynamic derivatives from wind tunnel tests have been obtained from a report on the similar cross section of the proposed Brusymfonien bridge.
The results obtained show an increasing critical mean wind velocity with increasing the center-to-center widths between the box sections. For the widest dual box girder, no stability limits were found. The response results confirm the stability limits and indicate a stabilization effect of the dual box girders at wind velocities below the point of modal coupling.
Place, publisher, year, edition, pages
Institutt for konstruksjonsteknikk , 2013. , 128 p.
IdentifiersURN: urn:nbn:no:ntnu:diva-22274Local ID: ntnudaim:9340OAI: oai:DiVA.org:ntnu-22274DiVA: diva2:648729
Strømmen, Einar Norleif, ProfessorBerntsen, KristianIsaksen, Bjørn