| With the rapid development of traffic,more and more highways and railways cross each other.Due to the influence of terrain and environment,the swivel construction method is generally adopted for the bridge crossing the railway.It is a new trend to adopt swivel construction method for hybrid girder cable-stayed bridge.The future development space is huge.Construction control is very important for efficient and safe construction.The engineering of composite beam swivel cable-stayed bridge is huge and complex,and there are many factors affecting the construction.How to effectively carry out construction control is a hot research topic.In this paper,a single tower hybrid beam swivel cable-stayed bridge is taken as the engineering background,the construction control of the swivel cable-stayed bridge is carried out,and the monitoring results are analyzed.The main research contents of this paper are as follows:(1)Combined with the construction method and structural characteristics,Midas /Civil is used to establish a finite element model to simulate each construction stage.The numerical calculation and mechanical performance analysis of each construction stage are carried out by using the frontal analysis method.The cable force and unstressed length of the stay cable are obtained.The cable force includes the cable force and initial tension of the completed bridge.The initial tension and swivel cable force,the completed bridge cable force and the design cable force are compared and analyzed respectively.The pre camber of the main girder,the pre elevation value of the main tower and the internal force and displacement parameters of the main bridge in the main stage are obtained,and the construction control is carried out based on this.(2)The monitoring data are analyzed and compared with the theoretical calculation value.The swivel system meets the requirements.The results show that the support is safe in the linear monitoring of the main beam;the elevation change of the formwork is less than the limit value,and the pre camber setting is reasonable;the elevation change of the main beam is stable,and the elevation adjustment scheme of the main beam is formulated to ensure the smooth closure stage;the horizontal deviation value of the main tower is in the safe range.The stress of each control section of main girder,main tower and main pier is less than the limit value,which meets the requirements.For the cable force tracking and monitoring,the invalid situation in the process of cable tension is analyzed,and the cable force adjustment scheme is formulated to make the cable force of the completed bridge reach the ideal state.(3)The weighing test is very important for the composite beam swivel cablestayed bridge.Before the weighing test,the counterweight was calculated theoretically and the preliminary counterweight scheme was formulated.After the preliminary counterweight scheme was implemented,the numerical calculation was carried out according to the weighing results.The counterweight adjustment scheme was formulated with the rotation eccentricity as the control target,and the adjusted scheme was implemented well.In this paper,the finite element analysis software is used for modeling and calculation,and the calculated value is used as the basis for construction control.The comparison and analysis of the monitoring results are carried out,and the elevation adjustment scheme and cable force adjustment scheme are proposed to make the construction smooth.Finally,the relevant experimental research on the weighing before turning is carried out,and the counterweight adjustment scheme is proposed.The research content of this paper has certain reference significance for the construction control of composite beam swivel cable-stayed bridge in the future. |
