CREEP EFFECTS AND STRESS ADJUSTMENTS IN CABLE-STAYED BRIDGES WITH CONCRETE DECK

Risultato della ricerca: Paper

Abstract

In construction stages of cable-stayed bridges with prestressed concrete deck, the influence of creep on stresses and strains is very important in order to foresee the final patterns of internal forces and displacements. In cantilever construction, the concrete deck can be considered, in each stage, as a continuous beam resting on elastic restraints, which modify with successive additions of new segments, until the last one has been assembled. In these stages stress relaxation in concrete occurs as well as vertical displacements increase. Ehen structure has been closed by inserting midspan segment, stress redistribution begins, due to creep. Deformation and internal force development in construction and service life modify stay stresses such as deck and pylon final profiles. It is necessary to prevent undesirable deformed shape of deck and pylon and to control the final stress pattern of deck and stays. The requested final geometry of the bridge is reached by adjusting stay axial forces during construction. A study is presented in which, by taking into account creep effects, the optimization in terms of deck and pylon deformed shape can be achieved through a sequence of stay force adjustments during construction stages. The presented analysis is based on the theory of aging linear viscoelasticity in order to give a useful tool for the conceptual design of cable-stayed bridges with concrete deck. The proposed procedure allows engineers to design by reducing and avoiding creep effects instead of calculating them with refined models since the first design step.
Lingua originaleEnglish
Stato di pubblicazionePublished - 2010

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Cable stayed bridges
Bridge decks
Creep
Concretes
Prestressed concrete
Viscoelasticity
Aging of materials
Engineers
Geometry

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title = "CREEP EFFECTS AND STRESS ADJUSTMENTS IN CABLE-STAYED BRIDGES WITH CONCRETE DECK",
abstract = "In construction stages of cable-stayed bridges with prestressed concrete deck, the influence of creep on stresses and strains is very important in order to foresee the final patterns of internal forces and displacements. In cantilever construction, the concrete deck can be considered, in each stage, as a continuous beam resting on elastic restraints, which modify with successive additions of new segments, until the last one has been assembled. In these stages stress relaxation in concrete occurs as well as vertical displacements increase. Ehen structure has been closed by inserting midspan segment, stress redistribution begins, due to creep. Deformation and internal force development in construction and service life modify stay stresses such as deck and pylon final profiles. It is necessary to prevent undesirable deformed shape of deck and pylon and to control the final stress pattern of deck and stays. The requested final geometry of the bridge is reached by adjusting stay axial forces during construction. A study is presented in which, by taking into account creep effects, the optimization in terms of deck and pylon deformed shape can be achieved through a sequence of stay force adjustments during construction stages. The presented analysis is based on the theory of aging linear viscoelasticity in order to give a useful tool for the conceptual design of cable-stayed bridges with concrete deck. The proposed procedure allows engineers to design by reducing and avoiding creep effects instead of calculating them with refined models since the first design step.",
keywords = "bridges, creep, staged construction",
author = "Piercarlo Margiotta and Granata, {Michele Fabio}",
year = "2010",
language = "English",

}

TY - CONF

T1 - CREEP EFFECTS AND STRESS ADJUSTMENTS IN CABLE-STAYED BRIDGES WITH CONCRETE DECK

AU - Margiotta, Piercarlo

AU - Granata, Michele Fabio

PY - 2010

Y1 - 2010

N2 - In construction stages of cable-stayed bridges with prestressed concrete deck, the influence of creep on stresses and strains is very important in order to foresee the final patterns of internal forces and displacements. In cantilever construction, the concrete deck can be considered, in each stage, as a continuous beam resting on elastic restraints, which modify with successive additions of new segments, until the last one has been assembled. In these stages stress relaxation in concrete occurs as well as vertical displacements increase. Ehen structure has been closed by inserting midspan segment, stress redistribution begins, due to creep. Deformation and internal force development in construction and service life modify stay stresses such as deck and pylon final profiles. It is necessary to prevent undesirable deformed shape of deck and pylon and to control the final stress pattern of deck and stays. The requested final geometry of the bridge is reached by adjusting stay axial forces during construction. A study is presented in which, by taking into account creep effects, the optimization in terms of deck and pylon deformed shape can be achieved through a sequence of stay force adjustments during construction stages. The presented analysis is based on the theory of aging linear viscoelasticity in order to give a useful tool for the conceptual design of cable-stayed bridges with concrete deck. The proposed procedure allows engineers to design by reducing and avoiding creep effects instead of calculating them with refined models since the first design step.

AB - In construction stages of cable-stayed bridges with prestressed concrete deck, the influence of creep on stresses and strains is very important in order to foresee the final patterns of internal forces and displacements. In cantilever construction, the concrete deck can be considered, in each stage, as a continuous beam resting on elastic restraints, which modify with successive additions of new segments, until the last one has been assembled. In these stages stress relaxation in concrete occurs as well as vertical displacements increase. Ehen structure has been closed by inserting midspan segment, stress redistribution begins, due to creep. Deformation and internal force development in construction and service life modify stay stresses such as deck and pylon final profiles. It is necessary to prevent undesirable deformed shape of deck and pylon and to control the final stress pattern of deck and stays. The requested final geometry of the bridge is reached by adjusting stay axial forces during construction. A study is presented in which, by taking into account creep effects, the optimization in terms of deck and pylon deformed shape can be achieved through a sequence of stay force adjustments during construction stages. The presented analysis is based on the theory of aging linear viscoelasticity in order to give a useful tool for the conceptual design of cable-stayed bridges with concrete deck. The proposed procedure allows engineers to design by reducing and avoiding creep effects instead of calculating them with refined models since the first design step.

KW - bridges, creep, staged construction

UR - http://hdl.handle.net/10447/56355

M3 - Paper

ER -