Carbon nanotubes and their application to very long span bridges

[摘要] Spanning long distances in bridge construction relies mainly on the structure;;s efficiency and materials used. Whereas structural design for high rise building is fast-expanding, the overall design of long span bridges has not progressed significantly, and the increase in span chiefly depends of new materials. Carbon nanotubes, with their extraordinary Young;;s modulus and tensile strength far exceeding steel, allow the production of ultra-strong cables which can be used for cable- based structures like suspension bridges. However, since nanoscopic elements are used to produce kilometer-long cables, it is difficult to calculate their real strength, taking into account physical and production defects. This thesis provides the background necessary to understand the complexities involved in creating a kilometer-long cable made of carbon nanotubes. It also presents a computer program that computes the theoretical tensile strength of such a cable for a given set of assumptions about nanotubes. Scenarios varying the mechanical properties (tensile strength and Young;;s modulus) are applied to a cable-stayed and a suspension bridge, and it is shown than spans longer than five kilometers could be realized with such technology.

[发布机构] Massachusetts Institute of Technology