The Study Of The Force Characteristics And Construction Control Of Ultra-high Continuous Rigid-frame Bridge

With the implementation of the western development strategy and considerable investment in national highway transportation infrastructure,the highway transportation industry has entering a new era of fast development.Southwest China is famous for its mountainous topography,so it is of great importance to develop long-span bridges with high piers during high-grade highway construction.The huge difference in elevation between mountains provides a large development potential for long-span continuous rigid frame bridges with ultra-high piers.However,comparing with the low pier continuous rigid frame bridges,the ultra-high pier and long-span continuous rigid frame bridges often have more complex and critical problems in structure stabilization,stress and construction control which are caused by pier height and other factors.In this paper,Ma River Bridge has been studied and analyzed and results achieved are as follows:1.The effect of asymmetry of pier height on stress and deformation caused by temperature,live road,shrinkage and creep,and permanent load of ultra-high continuous rigid frame bridges is analyzed.Varying patterns of girder's inner force,stress distribution of bridge pier and the displacement of pier crow with different combinations of pier height are presented.2.Aimed at the issue of the stabilization of ultra-high continuous rigid-frame bridge,this paper has discussed the influence of pier height change on the stability of bridge construction under different conditions of tallest bare pier status,longest cantilever status and accomplished bridge status.3.The influence of collar beams between the double-shaft and thin-wall high piers on structural stability is analyzed.This paper also made a theoretical analysis on dismantling timing of the collar beams between the double-shaft and thin-wall high piers of Ma River Bridge.Results showed that it is reasonable to dismantle the collar beams between the double-shaft and thin-wall high piers before the side span is locked.4.Based on the temperature effect theory,analysis of the influence of temperature effect on structural deformation under the condition of tallest bare pier and longest cantilever has been made.Vertical control measures in the process of main pier construction and control measures to reduce the influence of temperature in the process of main beam construction have been presented,which has provided the measure and theoretical basis for the construction control in Ma River Bridge.Results showed that the measure worked positively.