Research The Avail Of The Strength For Fangfan Double Curved Arch Bridge In Hubei By The Steel-box Method

With the continuum development of our country's economy, the capacity of the traffic transportation had greatly rised , and the capacity for the highway of the traffic transportation had greatly rised too. The burthen because of the highway and bridge become more and more serious . Added with the some aging or disrepair or restrict of originally design standard , the carrying capacity for today's status has become one of attention question for discussion problem of engineering field and academe.The double arch bridge is a bridge type that invented by our country's people . It is also a characteristic arched bridge type in China. In 1960s and 1970s, lots of arched bridges were built up in China. It ever played an important position on fastening the construction speed of highway and bridges and economic development in China. However, it was not perfected on design theory and construction, adding with the shortcoming for structure characteristic of the double arch bridge and the scarcity of stability in construct and the feebleness of the break_ cover for repelling the bending , as well as increment traffic maintenance in recent years, these double arch bridges built in 1960s and 1970s gradually exposure the shortcoming in structure and design, appearing disease and scathe in different degree.This thesis depict how the double arch bridge come into being and the development of the double arch bridge first. Then , explain the composing and characteristic of the double arch bridge . Next, tell of the actuality of the study on the carrying capacity . Based on these , gained the content of study on this thesis . the thesis analyze the different types of disease on the double arch bridge and the causations for the disease . At the same time , integrate the composing of the double arch bridge pertinencely analyse the situation of the disease for different parts and discuss the factors that influence the carrying capacity of the double arch bridge . Combined with the factors and the commonly principle and basic theory for strengthening bridge, rationality analyze the common method for strengthening bridge.This thesis take the Fangfan bridge built in Hubei province Dawu county as an example . Accomplish the detailed examine and reconnaissance to the appearance disease to the bridge , and mensurate the intensity of concrete to this double arch bridge . Mensurate and calculate and analyse the flexibility-degree , stress , coefficient of landscape orientation-distributing of the double arch bridge at the dead weight . Based on these , assess the carrying capacity of the bridge before it been strengthened, at the same time find out the mostly factors that influence the carrying capacity of the bridge . According as the mostly factors that influence the carrying capacity of the bridge and the theory and merit of the steel-box method to strengthen bridge , using the steel-box method to strengthen this bridge had been put forward and discourse upon its technics of construction . After the bridge had been strengthened , according to contrast and analyse the data before and after the bridge been strengthened, demonstrate that the carrying capacity of the bridge had a great increase and prove the fact avail using the steel-box method to strengthen bridge , moreover testify that the mostly factor be finded before that influence the carrying capacity of the old bridges is right, and hope this thesis can be an reference for the appraise and to strengthen of the same old type bridges .