Long term behavior of cable strayed bridges

In the design of a structure, one of the most difficult parameter to assess is how the initial condition of a structure will change with time. During its life span, a structure can be subjected to different loads, changes in geometric configuration and even changes in its mechanical properties. Among all factors that can affect the geometrical reconfiguration of a structure (i.e. settlements and overloads) creep is one of the most important given its inevitability and because of its persistent effects (normally estimated as ten thousand days). Due to the effect of creep, a structure tends to amplify its deformation under a given load condition over time, and the final deformation can even reach values five or six time grater than the initial ones. During the design, the fact that deformations grow with time can be a difficult condition especially for highly indeterminate structures like cable stayed bridges where the stresses are related to the geometric configuration of the structure itself. In concrete cable stayed bridges, in fact, the increase in the deformation of the deck and the pylons over time leads to a decrease in the initial tension in the stays with an obvious difficulty in the design phase of the structure. The first chapter of this thesis illustrates and explains one approximate method used to estimate the effect of creep on a concrete structure. The method proposed in this thesis is the "Age-Adjusted Effective Modulus Method". It was chosen among others because it is one of the most commonly used, and because it is highly accessible.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Scotti, Andrea, 1978-

Advisor dc:contributor.advisor

• Jerome J. Connor.

• Civil and Environmental Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/29408

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/29408