Construction And Control For Superstructure's Demolition Of Reinforced Concrete Multiple Arch Bridge

The demolition of bridge is different with the building of bridge. Different bridges in accordance with their own characteristics and environmental factors might select suitable different demolition methods. At present domestic studies of demolition construction methods and demolition construction control for bridge are not systematic and perfect. In this thesis, based on the Liuzhou Jinglan Bridge's demolition project, demolition method and construction monitoring of a reinforced concrete multiple arch bridge are studied.The main methods for bridge demolition are blasting and mechanical removal. The Jinglan Bridge studied in this thesis, in need of retaining the substructure, must be demolished by machinery. Several demolition plans are established according to the structural behavior of a multiple arch bridge, and the better plan of construction is selected after contrasting and analyzing.The load-carrying capacity of bridge will decrease after many years' operation, and uncertain factors which influence demolition negatively may increase, thus construction monitoring in dismantling process is essential. For the multiple arch bridge mentioned, change of horizontal thrust at piers' top may bring the potential risk. According to the selected construction plan, stress and displacement are simulated using finite element software in each dismantling construction stage. Data collection, parameter adjustment and comparative analysis between measured and theoretical data make up a construction monitoring alarm system to ensure the smooth construction progress of demolition.Not only stress and displacement should be controlled, but arch's stability must be considered to make sure that bucking will not happen in demolition of the arch bridge. The thesis has carried on the simulation analysis regarding this.With the lapse of time, more and more bridges have to be demolished and rebuilt. Therefore the demolition of bridge is a new subject which bridge engineer must begin to study. This thesis carried on the research and implementation of multiple arch bridge's demolition construction control, and provided the technical support for superstructure's smooth demolition of the Jinglan Bridge. Research achievement may provide some useful references for similar structure's demolition in the future.