|
Descripción
|
|
|---|---|
| Bridge aerodynamics has attracted the interest of wind engineers for a long time. This interest rose after the Tacoma Narrows disaster, when a four-month-old bridge collapsed under a wind condition of only 20 m/s. Several dynamic effects generated by wind in bridges were described and studied, namely, vortex induced vibration, flutter, galloping and buffeting. In the second half of the twentieth century, improvements in construction techniques lead to longer and lighter bridges. Due to this, natural frequencies of bridges dropped to frequencies around a few Hertz. Dynamic effects were more likely to appear in these bridges. Many effort has been done to understand better all the effects that wind can create on a bridge. However, some relevant studies have been left aside. One of the main parameters that play a significant role is the barriers. This thesis tries to give a deeper insight on the influence of the barriers in the different aspects. Even though the aerodynamics of any bridge sections is conditioned by many other aspects than just the barriers, such as the bridge section, mass, natural frequencies, etc., some ideas are extracted to design barriers so that they increase the stability of the bridge. Several different barriers have been tested over different bridge sections. In the literature, porosity is pointed out as one of the most relevant design parameters. Throughout the thesis barriers with different porosities have been tested on different bridge sections. For the tests, three different wind tunnels have been used, two in the Instituto Universitario de Microgravedad Ignacio da Riva, in the Universidad Polit¿ecnica de Madrid and another in the Centro Interuniversitario di Aerodinamica delle Costruzioni e Ingegneria del Vento, in the Universit degli Studi di Firenze. As the influence of the barriers is not only important in the aeroelastic behavior of the bridge, in some of the configurations other tests have been performed, such as static loads generated on the bridge or on the users of the bridge (in this case, on a train), or flow condition created in the deck by the shear layer shed by the upper part of the barrier. This thesis is divided in 4 chapters. In the first chapter an introduction to fluid-bridge interaction is presented and the state of the art in the topic is summarized and the objectives of the thesis are described. In chapter 2, the results of a set of tests on a high speed train bridge are displayed and analyzed. In chapter 3 the configuration of a flat plate with barriers is studied. Finally, in chapter 4 the main conclusions of the thesis are drawn, and proposes future work to improve the current knowledge about the influence of the barriers in the stability is proposed. | |
|
Internacional
|
Si |
|
ISBN
|
|
|
Tipo de Tesis
|
Doctoral |
|
Calificación
|
Sobresaliente cum laude |
|
Fecha
|
16/12/2016 |