Design And Experimental Analysis Of Flexible Jig Frame For Steel Structure Bridge

The fabrication of steel structure bridge includes prefabrication in factory and welding assembly of fabricated components on installation site.So,jig frame is vitally needed process equipment during prefabricated operation.At present,there are many defects in the traditional frame built in the factory.firstly,the high building cost.For building a jig frame,laying the foundation,cutting and welding steel is needed,which cost a lot on manpower and material.Secondly,a lot of waste.After bridge body welding,jig frame will be removed and nonreusable.Thirdly,long time consuming.It takes at least a month or more from design,foundation fixing,cutting,welding,measuring,adjusting and removing.Fourthly,environmental pollution.The building and removing of jig frame will produce much soot and harmful gases.Aim at the defects of jig frame,this paper presents a concept of flexible jig frame,which can change the length,width,height of the three directions of jig frame's size,and perform advantages such as easy to install and disassemble,and the parts can be reused.Flexibility is mainly reflected in the height can be adjusted by Screw Lifter,and the width can be adjusted by changing the spacing between the two rail beams,and the length be adjusted by increasing the length of the track beam and the number of trolley.The flexible jig frame performs the same function with no defect,and can completely replace the rigid jig frame for steel structure bridge manufacturing.The paper puts forward two design schemes of the flexible jig frame and then selects a more flexible design through comparative analyses.The flexible equipment system consists of support device and traction device.The support device mainly comprises lifter,main beam,vehicle,track,track beam and rail clamp,and the traction device mainly comprises steel wire rope,pulley and winding device.In order to verify the stability of the flexible jig frame,a model was designed and studied by scale.Through the linear static strength analysis and model experiment analysis of different load and flexible adjustment of the system model.It is proved that flexible jig frame scheme has good stability.Supporting steel bridges to reach the stiffness requirements.