Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Long-term effect analysis of prestressed concrete box-girder bridge widening
Research highlights ► A revised method of shrinkage and creep was presented. ► A prestressed concrete box-girder bridge widening was analyzed. ► Bridge widening should be performed 6 months after widening.
Abstract To make an analysis of long-term effect of prestressed concrete box-girder bridge widening, a revised method of shrinkage and creep is presented by incremental method on base of energy principle. Continuous change of stress aroused by concrete shrinkage and Young’s modulus of concrete over each time interval is considered, and creep effect due to constrained shrinkage strain is also taken into account. A calculating program was compiled according to this method, which was validated by test results. Then an example of prestressed concrete box-girder bridge widening was analyzed by use of this program. According to calculated results, longitudinal tensile stress at the flange of the new girder can reach 2.84MPa due to shrinkage and creep effects of new box girder after 10years, which may lead to crack of concrete. It is suggested that bridge widening should be performed 6months after new girder is cast. Compared with new box girder not widened which is in service independently, the total prestressing loss of the widened new box girder decreases 31–35% 10years after bridge widening. However, prestressing loss of the old box girder aroused by shrinkage and creep of the new box girder can be neglected.
Long-term effect analysis of prestressed concrete box-girder bridge widening
Research highlights ► A revised method of shrinkage and creep was presented. ► A prestressed concrete box-girder bridge widening was analyzed. ► Bridge widening should be performed 6 months after widening.
Abstract To make an analysis of long-term effect of prestressed concrete box-girder bridge widening, a revised method of shrinkage and creep is presented by incremental method on base of energy principle. Continuous change of stress aroused by concrete shrinkage and Young’s modulus of concrete over each time interval is considered, and creep effect due to constrained shrinkage strain is also taken into account. A calculating program was compiled according to this method, which was validated by test results. Then an example of prestressed concrete box-girder bridge widening was analyzed by use of this program. According to calculated results, longitudinal tensile stress at the flange of the new girder can reach 2.84MPa due to shrinkage and creep effects of new box girder after 10years, which may lead to crack of concrete. It is suggested that bridge widening should be performed 6months after new girder is cast. Compared with new box girder not widened which is in service independently, the total prestressing loss of the widened new box girder decreases 31–35% 10years after bridge widening. However, prestressing loss of the old box girder aroused by shrinkage and creep of the new box girder can be neglected.
Long-term effect analysis of prestressed concrete box-girder bridge widening
Wen, Qing-Jie (Autor:in)
Construction and Building Materials ; 25 ; 1580-1586
17.09.2010
7 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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