Study On Construction And Installation Technology Of Three Storey Double Abdominal Double Folded Beam For Two Reheat Tower Boilers

With the development of thermal power unit to high parameter and large capacity,its design requirement for boiler steel structure is more and more high,especially for the large plate and beam in boiler steel structure,and the design size and weight are bigger and bigger.At present,the secondary reheat tower boiler steel structure slab of the domestic power plant 1000 MW unit is designed with three layers of double beams,the laminated beam is an n-shaped structure,the length is divided into three sections;middle and lower beam for long "I" type structure.The three stack beams are connected by high-strength bolts.Then the ends flange is connected to the 200 mm thick end plate.The large plate beams are supported by the 200 mm end plates on both sides and transmit the force to the main steel frame of the boiler.There are many connections between the large plate and beam,and all bolts need to be connected in all directions of the three-dimensional surface.The bonding surface requires close contact,and the connection way is complex,which brings severe test to production and manufacturing.This paper studies the establishment of a complete,unified reference system,identifies the baseline before the stacking beam combination,and manufactures them in strict accordance with the benchmarks,ensuring the perforation rate and the friction surface requirements of each connection node of the large plate beam.According to the characteristics of large and heavy weight of large slab and beam,the horizontal combination and horizontal welding are used to discard the welding way of the traditional "T" fillet weld "ship form",which improves the work efficiency and greatly reduces the safety risk.The hole of the superposed face between the large plate and beam overlapped with the factory matching drilling way,which effectively eliminates the influence of the inconsistent welding deformation and can produce at the same time,which greatly shortens the production cycle.The welding of butt weld of large plate and beam with large thickness is made by flame cutting method.The "X" groove is made,which achieves the same quality requirement as mechanical processing "U" groove,and shortens the construction period and reduces the production cost.Under the condition of "U" groove without mechanical processing,it provides a new idea for butt weld of large plate.In order to realize the overturn of the large plate beam,the overturn frame of the large plate beam is designed and manufactured.The turnover rack has the advantages of simple structure,convenient operation,high working efficiency and low safety risk.It can turn over the steel structure big plate beam with different weight and length,and achieve sustainable utilization.Through this process to solve the boiler frame girder of large size and high quality single,high precision,thick plate,poor weldability,the component is difficult to turn over,the bolt hole group,deformation is not easy to correct,reduce construction cost and safety risk,improve the accuracy and efficiency of construction installation in Huaneng Laiwu power plant boiler steel stoplog three layer double web project.