Adjustable Type Steel Arch Stability Analysis And Construction Process Control

The adjustable steel arch is a new type of steel arch,which combines the advantages of the beret steel arch and the 64 military beam steel arch.It has the advantages of less steel,good mechanical performance and strong adaptability.Therefore,it has been widely used in the construction of reinforced concrete arch bridge in recent years.In the process of design and construction of steel arch,stability is an important control factor,but at present,the stability of the adjustable steel arch is relatively less,and the stability control of the adjustable steel arch is lack in practical engineering.Therefore,in view of the fine-tuning steel arch,the stability problem is studied,and the stability control method in the actual construction process is discussed.Taking the Yang Gang River Bridge as the engineering background and taking the Midas/Civil software as the platform,the influence factors of the adjustable steel arch are studied.Through the study,the results are as follows:?Under the condition of changing the rigidity of various kinds of bar parts in the steel arch frame,compared with other members,the lower chord,transverse brace and parallel link have more obvious effects on the stability of the steel arch frame.? Considering the stability and economy,the horizontal connection of the upper chord of the steel arch and the horizontal chord connection of the lower chord are the best layout.? The lateral stability of steel arch is improved with the increase of the span ratio when the form of steel arch instability is external plane instability.? The cable wind cable can significantly improve the lateral stability of the steel arch,and for the study of the micro-adjustable steel arch,considering the symmetry,the cable wind cable should be arranged in the upper part of the steel arch.Considering the characteristics of actual engineering,the optimum angle of the cable's angle is from 30 degrees to 50 degrees,20 to 45 degrees.On the basis of elastic stability analysis,considering the geometric nonlinear prohlem of steel arch,nonlinear analysis on the stability of linear analysis results are relatively more conservative,nonlinear analysis is more realistic conclusion.At the same time,the greater the initial geometric defect of the structure,the worse its stability is.Finally,the stability control of the adjustable steel arch frame in the construction process of the Yang Gang River Bridge is carried out.The stability control of the steel arch is divided into two stages in the actual construction process,that is,the stage of the hoisting of the steel arch and the stage of concrete pouring.In the lifting stage,mainly consider the force stability between cable and arch section,to control the alignment.In the concrete pouring stage,it is mainly considered whether the stability of the steel arch frame under different load conditions meets the requirements of the standard,and controls and adjusts its pouring sequence and pouring mode.Through the construction stability control,Yang Gang river bridge successfully completed the main arch circle closure.