Analysis And Research For Critical Problems In The Construction Process Of Concrete Filled Steel-tube Tied-arch Bridge

In our country,concrete-filled steel tubular(CFST) arch bridges have become a new technology of the bridge construction in recent years.It has the merits of light dead weight,great strength,strong distortion resistant capacity and so on. It can preferably satisfy these requirements such as less materials, light erection weight, simple construction,and great bearing capacity.It is a kind of more ideal structure form for long-span arch bridges.The construction of CFST arch bridge with long span is always divided into many working procedures,which are completed step by step while construction process is long and complex.So,the simulation analysis on the construction and construction control of long span CFST arch bridge is essential.Based on the Construction Control of Xing-xian Bridge in the city of Suzhou,Two key techniques for construction control of Long span CFST Arch Bridge are analyzed and studied.The main contents of this paper are summarized as follow:In the installation process of tied-arc bridge cross beams,Different orders of installation will result in various influence to the internal forces of the arc rib,If the installation orders is not appropriate,The internal forces of the arc rib at the end of the installation will be much bigger than that in the process.In this paper,The Order Optimization Matrix Method is proposed,and an analysis program of cross beams installation optimal order is developed,The method is finally applied into the Xing-xian Bridge in the city of Suzhou,and ensured the construction process safe and go on well. The Order Optimization Matrix Method is simple and practical.It can be used in this problems which obey or approximately obey the Principle of superposition,Such as:tensioning oder for hangers,construction oder for cross beams,bridge deck,bridge floor paving,and so on.It is obvious that the proposed method is practical and can be widly used in the correlative engineering.In the tensioning process of hangers for tied-arc bridge,The latter hanger will have influence to the tensioning force of the former as a result of different tensioning orders of different hangers.If the hangers is tensioned directly according to the designing order,The final tensioning force in hangers is hardly content with the designing requirement.So it is a key and difficult problem to determine the initial tensioning force in hangers in the construction process of tied-arc bridge.Further more,if the hangers are protected by steel tube of certain thick,it will be very difficult to measure the tensioning force.In this paper,The initial tensioning force in hangers is optimized and calculated in combination with a concrete filled steel tube arch-tied bridge,Finally,a measuring method for tensioning force in semirigid hangers is proposed,The method is finally applied into the construction monitoring for Xing-xian Bridge in the city of Suzhou,And the result indicate that the measuring method is convenient and practical.It can provide some experiences to the correlative engineering.