| Simply-supported-structure continuous bridge with quickly construction speed,finished beam producted by template in a high quality and driving comfort,which has been widly used in the medium and small span beam bridge in mountainous area hignway currentely.As we all know,the live load is much bigger than dead load in the medium and small span beam bridge,under the cation of prestress,which easily lead to the excessive amount of creeping camber with a wavy deck.The creeping of concrete on the arch has the effect of two aspects,on the one hand,cause the loss of prestress to reduce the arch;on the other hand make the section strain of component concrete increase to magnify the arch.Generally speaking, the latter is the main, although the prestress is decreasing, and the arch is growing.The oversize arch of the deck will significantly reduce the driving comfort.The experts at home and abroad made more research on the effect of ride comfort in railway,but less research on road.With the increase of our country highway mileage, the trend of private car’popularization and the higher proportion of the national travel by car,the driving comfort will be catching more and more attention.In the mountainous area highway of route length, the propotion of bridge is high and most of them are small and medium span prestressed concrete bridge,so its driving comfort research will get more attention.This paper carry out the analysis and calculation of concrete creep effect on the Simply-supported-structure continuous beam bridge, it; the analysis and calculation of vehicle-bridge interaction of vibration, the evaluation of high-speed driving comfort, the limits of concrete creep arch, through both way of design and construction are put forward to control the creep camber and the structural design method by considering driving comfort for the series research, content is systemic. Firstly, it gives the creep formula of Simply-supported-structure continuous beam bridge creep in theory, through the calc ulation of simply supported continuous beam bridge creep effect on project case,it is concluded that concrete creep deformation is mainly produced in the precast beam phase, the creep deformation complete about 70% ~ 80% percent of overall creep deformation which including early and later creep deformation. Secondly,it introduces the numerical method for solving the dynamic response and the vehicle-bridge coupling vibration equations are established,Newmark method is proposed to solve the dynamic response equation which greatly simplifies the calculat-ion and the numerical results accuracy can satisfy the requirement of engineering practice. With mean-square value of vibration acceleration as the driving comfort evaluation index, it received limitation of creeping arch under the number of different span,imparity of span and the different driving speed. Finally,in order to improve the wavy deck which formed by the excessive amount of creeping camber, for the newly built bridge, partial prestressed and fining design should be advocated, besides,which can reduce the prestressing degree and optimize the layout of prestress-steel; For the problem of bridge, within the scope of the common span and across combined, the improving method of control the midspan least pavement thickness and increase the pier top pavement thickness can be used.To sum up, this article has important theoretical and practical value to prevent the driving comfort of Simply-supported-structure continuous beam bridge and reducing maintenance cost... |
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