| On highway engineering construction, there are many kinds of box girder construction methods, the method for cast-in-situ stents, there are a variety of support build-up method, using bailey truss and used in combination with high formwork erection method, there were many advantages.But bailey truss as a specific performance for the brace system is still not clear, based on the experiment monitoring, theoretical analysis, model validation aspects of comparison, on the premise of guarantee the project security, to explore the bailey truss elements and joint use of high formwork engineering, and construction of mechanical properties of the vertical rod, and the following conclusions.(1) In normal bridge construction, the bar on the bending moment is small, negligible.(2) Below the flange of each bar in axial compression state in general, the internal force is roughly within 5 k N, but complex loading, tension is seen at the beginning of the construction of the upper level, suggesting the bowls bowl with an upper limit pin of important role.(3) The web below each bar in axial compression state, with smooth construction internal force increases, the maximum internal force roughly between 15 to 25 k N.Slightly smaller than stay away from the pier pier near the point of axial force.(4) In the process of construction, pouring time to support the influence of the axial force is more noticeable, casting faster bridge at the end of the construction of a rack body in axial force fall back, and slower construction highway to fall back range is very small.(5) In the box girder casting, upright pole stability have larger safety reserves.At the same time, the template scaffold design theory is not yet mature, the template is not fully support the theoretical calculation results reflect a variety of complex factors in the construction practice of, result in construction practice is not fully on the basis of the theoretical analysis results, but still stay on the field experience validation phase.(6) In combination of stents, steel tube column section and steel pipe support of interface is liable to occur in engineering node failure, lead to the risk factors of local and overall collapse.Need to focus on observation in the construction, and USES the special construction measures.(7) When the Midas simulation, bailey truss of the actual beam deformation values are slightly larger than the handbook of equivalent beam deformation value, that is to say, in terms of the deflection deformation, the manual calculation method for partial unsafe.In actual construction design, it is recommended that the safety factor of more than 1.25.(8) The Midas simulation analysis of the stability of the support, the most unsafe mode can still guarantee the safety factor of 2.48, shows that combination of stent has good applicability in engineering. |
