Research On The Key Technology In Construction Control Of Continuous Beam Bridge In High-speed Railway

As the rapid development of high-speed railways in China, the concrete bridge has wider application, especially the prestressed concrete continuous beam bridge which is the first choice for crossing the road and the river because of small deformation, smooth guide-way, simple maintenance, severe structural stiffness and well seismic performance.In order to satisfy the high speed driving with safety and stable of the trains, the unballasted track which is commonly-used instead of laying the sleeper or cement rail can reduce maintenance, decrease the dust and beautify the environment. Besides, the train speed can reach to over 200 kilometers per hour. Due to the fact that the rails are directly laid on the concrete beam surface that needs high smoothness, so the control on alignment and stress of the bridge requires more accurate concerning the construction control.In the construction process of prestressed concrete continuous beam bridges in high-speed railways, structural internal force and deformation are not only changed with the length increase of bridges, the demolition of temporary consolidation and the closure construction of bridges, but also influenced by many uncertain factors such as temporary load, construction scheme and surrounding temperature. Therefore, it is necessary to monitor and control the stress and deformation in construction process by effective measures as to guarantee the design requirements on quality and alignment of the completed bridge.Based on the characteristics of high alignment requirements about continuous beam bridges in high-speed railways, firstly, the development situation of high-speed railways and the control theory of continuous beam bridges construction control are proposed. Secondly, the key points are studied, including the settlement deformation of piers and abutments, loading test of cradle, the experiment of prestressed channel, the control instruction of camber, the smoothness control of beam surface and long-term deformation of bridge structure after completing the bridge. Last, gray system theory is applied in the Continuous Beam Bridge Crossing Chang-Cheng Expressway which belongs to beijing-shanghai high-speed railway. According to the practical experience and theoretical analysis, the conclusion is drawn that is used as the reference for construction control on continuous beam bridges in high-speed railway in the future.At last, based on a comprehensive summary of the main work about this thesis, several problems on this research topic demanding study further are brought forward.