Principle And Engineering Application Of Erecting Main Cable Of Suspension Bridge Based On Scale Cable Strand Method

The existing domestic suspension bridge main cable erection method is the layer spacing control method,which has apparent disadvantages.For example,construction efficiency is constrained by the construction environment,low cable adjustment efficiency at night,etc.With the increasing demand for building suspension bridges in complex construction environments,such as high altitude areas or cross-sea areas,the disadvantages of this method are infinitely magnified.So there is an urgent need for a main cable erection method that can be applied to various construction environments and has good construction accuracy.This master dissertation proposes an improved prefabricated parallel wire strand main cable erection method,the scale cable strand method.And then,the dissertation explains the erection principle of this method,discusses its construction accuracy when used in actual projects,and proposes the general process of constructing the scale cable strand method.The main research contents,methods,and conclusions of this dissertation are as follows:(1)Based on the calculation theory of the linear suspension line of the suspension bridge and the principle of the non-stress state,this dissertation elaborates the focus of the scale cable strand method and erection steps.And using the C++ language,the calculation procedures of the spacing control method and scale cable strand method of main cable erection are prepared.Comparing with the actual measured data of the background project verifies the correctness of the calculation procedures.Because the existing research data can match the change law,which is about the span height difference of the cable strand and the amount of the cable strand.It also proves that the accuracy of the calculation results can meet the actual engineering requirements and provide support for the subsequent calculation of the reliability of the cable strand erection.(2)Based on the Monte Carlo method of reliability theory,calculating the reliability of single cable strand erection using C++ programming language,the results show that: the method error has little influence on the reliability of the stranded cable to be erected by the scale cable strand method which is almost negligible;under the result of manufacturing error and measurement error,the reliability of the single strand erected by the two main cable erection methods increases with the increase of control accuracy,and has the same trend of change;however,under the same absolute control accuracy,the reliability of the single strand erected by the scale cable strand method is more excellent than that of the layer spacing control method,no matter which error is used.(3)This dissertation discusses the parameters sensitivity of each single strand erection influence factors.The results showed that: regardless of the span and the control accuracy,the manufacturing error has a pronounced impact on the reliability of the erection of various types of cables.And the temperature measurement error has the most significant effect on the measurement errors.This law is the same for the two main cable erection methods.However,under the same parameter variation,regardless of which error,the reliability of the single strand erected by the scale cable strand method is more excellent than that of the layer spacing control method.(4)Based on the two main cable erection methods,this dissertation discusses the distribution of non-stress lengths and the reliability of the main cable line shape in the erection of each layer of cable strands.And during this analysis,the relative drape,relative temperature,and longitudinal inhomogeneous temperature field errors are considered.The results show that:under the action of error factors,using the scale cable strands method,the non-stress length of each layer can still ensure the same distribution.So the error generated by the erection of each layer will not be propagated with the erection process.While the layer spacing control method,the non-stress length error of each layer of cable strands erected with the main cable is accumulated.So the reliability of the main cable line shape of the scale cable strands is more excellent than that of the layer spacing control method.(5)Based on the background of an actual large-span suspension bridge project,this dissertation discusses the complete construction process of the scale cable strand method.The location of the scale cable saddle in the tower and anchorage arrangement and the structural structure,size design,and application scope of the scale cable saddle are given in this dissertation.Using ABAQUS verifies its strength and stiffness to meet the engineering requirements to provide a reference for writing the construction plan of the scale cable strand method for subsequent suspension bridges.