Abstract: The Exhibition Hall 1 of the Phase I Area B Project of Shaoxing International Convention and Exhibition Center has a rhythmic staggered roof with a non-column span of 72 meters.The design and construction of the steel structure and metal roof system are difficult,and the construction period of the Exhibition Hall 1 is extremely tight which is required to be constructed and put into use in the same year.To solve the problems,the project makes full use of the characteristics of EPC mode.The design and construction subjects participate in the design scheme consultation,in which the priority payment requirements,site construction efficiency and inter-professional cohesion are regarded as the key points of design management.The design schemes of the main body and metal roof are finally implemented after study and comparation,and good results are obtained:
1) In view of the large-span special-shaped architectural form,a long-span steel structure scheme suitable for the rhymic staggeredplatformroof is innovatively put forward through the comparison of two form-finding schemes,one of which is the form-finding of roof substructure,and the other one is form-finding of main steel structure.The giant truss is arranged at the staggered platform to improve the overall stiffness and structural efficiency of the roof,through which the organic combination of roof modeling and reliable structure is realized.The analysis and verification show that the structural scheme has strong bearing capacity and excellent seismic performance.The structure greatly reduces the difficulty of design and construction of metal roofs,which is economical,reliable,and beautiful.It lays a good foundation for ensuring the construction period of the project,and can provide a useful reference for the selection of similar (rectangular tooth shaped roof) structure schemes.
2) In view of the slope finding scheme of the main steel structure,in order to further improve the construction efficiency of the roof system,a comparison of the three schemes of reverse installation of metal roof floor,forward installation of overhead floor and forward installation of direct laying floor is conducted,a metal roof system with "separated load-bearing structure of long-span bottom plate and purlin system" is innovatively proposed.The high-wave steel bearing plate leap over the steel structure divisions with a span of 4.5 meters,and is directly laid on the completion surface of the steel structure,which changes the operation mode of the traditional metal roof system.The supporting components of roof bottom plate are integrated into the main steel structure to reduce the aerial working process of roof system.The operation efficiency and construction safety of the metal roof system are greatly improved.The roof bottom plate is separated from the purlin system,and the weight of the structural layer is directly transferred to the main steel structure from the roof bottom plate,so as to improve the utilization rate of the main steel structure.The purlin system bears small force and saves steel,which only supports the roof plate.In addition to the roof purlin,no other parts penetrate the TPO waterproof layer to form a real "two waterproofs" and improve the waterproof effect of metal roof.
The project eventually takes 112 days to complete the construction of steel structure and metal roof system,which is nearly 4 months shorter than that of similar projects.At present,the project,which reflects the great advantages of the EPC mode,has successfully passed the acceptance of the main body and roof engineering,and has achieved the scheduled delivery and trial operation.The project reflects the great advantages of the EPC model.