The Fenghua River Bridge is a major structure on the highway between Hengzhang and Guojiachi, which is to be built with a four-span prestress concrete (PC) box girder and symmetrical cantilever castings. In this paper...The Fenghua River Bridge is a major structure on the highway between Hengzhang and Guojiachi, which is to be built with a four-span prestress concrete (PC) box girder and symmetrical cantilever castings. In this paper, a finite element method (FEM) model is set up to study the effects of concrete differential aging time on the construction phases of the Fenghua River Bridge by calculating the vertical displacement of the folding segment of the middle span and the longitudinal bending moment of Pier 12#. In the model, the girders are classified into 150 changing sections based on the desgn scheme, and their construction is to be carried in 16 phases respectively to build 12 blocks connected by a side folding segment and a middle folding segment, covered with a second dead load and in completion for 20 years. It is found that the internal forces and deformations of the concrete structures at the aging time of 60 d are quite different from those of 0 d aging time while the behaviors of the structures of 120 d aging time is nearly the same as those of 60 d aging time― the differences are so small that can be neglected, suggesting that the creep develops obviously about one month after the cement is hardened and the development fades later on.展开更多
The electric power system is an ageing infrastructure and the need for making reinvestments is increasing. Strict economic regulation of the DSOs （distribution system operators）, forces them to search for more effic...The electric power system is an ageing infrastructure and the need for making reinvestments is increasing. Strict economic regulation of the DSOs （distribution system operators）, forces them to search for more efficient work processes and improved technical solutions. The main challenges for network companies today are implementing new technologies and become more efficient in every part of the asset management. The work processes must be optimized and the right projects must be prioritized for reinvestment. The purpose of this paper is to give insight into some of the challenges electric distribution companies are facing today. This paper is based on experiences from NTE Nett AS--an electric distribution company in the middle of Norway. The paper also describes some of the measures that have been done in NTE Nett and what people believe will be the situation in the future.展开更多
文摘The Fenghua River Bridge is a major structure on the highway between Hengzhang and Guojiachi, which is to be built with a four-span prestress concrete (PC) box girder and symmetrical cantilever castings. In this paper, a finite element method (FEM) model is set up to study the effects of concrete differential aging time on the construction phases of the Fenghua River Bridge by calculating the vertical displacement of the folding segment of the middle span and the longitudinal bending moment of Pier 12#. In the model, the girders are classified into 150 changing sections based on the desgn scheme, and their construction is to be carried in 16 phases respectively to build 12 blocks connected by a side folding segment and a middle folding segment, covered with a second dead load and in completion for 20 years. It is found that the internal forces and deformations of the concrete structures at the aging time of 60 d are quite different from those of 0 d aging time while the behaviors of the structures of 120 d aging time is nearly the same as those of 60 d aging time― the differences are so small that can be neglected, suggesting that the creep develops obviously about one month after the cement is hardened and the development fades later on.
文摘The electric power system is an ageing infrastructure and the need for making reinvestments is increasing. Strict economic regulation of the DSOs （distribution system operators）, forces them to search for more efficient work processes and improved technical solutions. The main challenges for network companies today are implementing new technologies and become more efficient in every part of the asset management. The work processes must be optimized and the right projects must be prioritized for reinvestment. The purpose of this paper is to give insight into some of the challenges electric distribution companies are facing today. This paper is based on experiences from NTE Nett AS--an electric distribution company in the middle of Norway. The paper also describes some of the measures that have been done in NTE Nett and what people believe will be the situation in the future.
