Research On Control Indicator Of Displacement Error On Bearing Replacement Of Girder Bridge

With the rapid development of the traffic construction of China,and the growth of bridge operation time and traffic volume,more and more bridges have varying degrees of disease damage.In the bridge structure,the support is the key component between the superstructure and the substructure of the bridge,and plays a connecting role.But because of the poor quality of the bearing itself,the quality of construction and installation,impact loads and increasing the aging of rubber bearing disease caused by the bridge structure adversely affected,the need for adequate attention,to replace the bearing to not work properly.Bridge synchronous jacking bearing replacement technology is widely used in support replacement construction.Because of its convenient prefabrication and easy standardization construction,girder bridge is widely used in small and medium span bridges,and the bearing diseases are prominent.For the common girder bridge(such as hollow plate beam,T beam,composite girder,continuous girder),with prefabricated transverse connection beam bridge and continuous girder bridge belongs to statically indeterminate structure,bridge jacking process is equivalent to a statically indeterminate structure imposed forced displacement,make the structure produce the additional force.In the actual jacking construction,the method of "lateral synchronization and longitudinal pier by pier" is often adopted.For continuous beam bridge or continuous girder bridge with continuous deck structure,the total displacement of single pier synchronous jacking is studied.There is a synchronous displacement error phenomenon due to the construction technology,equipment precision,jack position,pad stone elevation and other reasons in the synchronous lifting,the impact on the internal force and the safety of the bridge structure,and also need to drop beam elevation error control index of synchronous displacement error control index.The replacement of short duration,sometimes asked not to interrupt the traffic construction of small operating space,in order to ensure the safety in the process of lifting structure and bridge bearing replacement to maintain the original stress state of bridge synchronous lift displacement control index has significance in theory and practical engineering major.According to the structural characteristics of common girder bridge,analytical method and finite element method basic principle,according to the common bridge standard through the finite element software to simulate lifting conditions,analysis of beam bridge bearing replacement and jacking beam falling under the condition of the stress nephogram,analysis of prefabricated bridges during lifting of the hinge joints,the diaphragm,for the weak position of continuous deck,continuous box girder bridge pier roof box girder for weak position,according to the weak position of the maximum tensile stress of concrete and reinforced concrete crack width calculation of single pier Jacking Bridge in the process of synchronous lifting of total displacement,synchronous lifting error when the permissible value of displacement error occurs and the falling beam elevation error allowable control index.Due to the influence of construction error,external environment and bridge disease,the actual control error of bridge jacking displacement error is different from the theoretical calculation value.In the actual lifting construction process,take the grade of the lifting way,according to each level of Jack lift monitoring,lifting displacement monitoring and the weak position of stress changes and bridge cracks,the measured data and the theoretical data are compared.According to the analysis of structural parameter sensitivity,considering the structural parameters of the top lift get the amount,and the monitoring of the weak position change of stress data,give the theory the reasonable control index of safety coefficient,real-time monitoring of displacement after the amendment of the control index of practical jacking construction process.During the construction monitoring of the replacement of the actual engineering bearings,the construction is monitored by means of displacement and stress double control.According to the theoretical analysis of the theory of displacement error control index in actual bridge jacking process,theory of control index is corrected by the reasonable safety factor,control index obtained in the actual construction safety monitoring.It provides theoretical control index and correction method for construction monitoring of bridge jacking up and replacing pedestal.