Structural Design of Airport Terminal Building (Part 2)

3.3.2 Internal force and deformation analysis

The maximum combined stress ratio of the truss roof is 0.89, the maximum vertical displacement of the cantilever end in the load standard combination is 158mm, the relative deflection-span ratio is 1/126, the mid-span deflection is 55mm, and the relative deflection-span ratio is 1/272. Under the action of wind load in all directions, the maximum displacement of the column top is 20mm, and the maximum interstory displacement angle is 1/650. Under the action of earthquakes in all directions, the maximum displacement of the column top is 15mm, and the maximum interstory displacement angle is 1/666. The maximum combined stress ratio of space frame-roof is 0.86, the maximum vertical displacement of the cantilever end in the load standard combination is 155mm, the relative deflection-span ratio is 1/129, the mid-span deflection is 51mm, and the relative deflection-span ratio is 1/294. Under the action of wind load in all directions, the maximum displacement of the column top is 14mm, and the maximum interstory displacement angle is 1/928. Under the action of earthquakes in all directions, the maximum displacement of the column top is 12mm, and the maximum interstory displacement angle is 1/833. After comparative analysis, it can be seen that the stress ratio, deflection-span ratio, interstory displacement angle and other performance indicators of the space frame and truss all meet the requirements of the code, but the deflection of the truss and the displacement of the top of the column are larger than that of the space frame, which is different from the space of the space frame. Relatively strong.

4. Material comparison

The truss adopts rectangular steel pipes, material Q355, and the number is 7645. The minimum member is square steel 90×6.0, rectangular steel 1000×400×28×16, and the total weight is 1312895kg. The net frame adopts 16945kg, the material is Q355, and the number is 16945. The minimum specification is φ60×4, and the maximum specification is φ560×10. The total weight of the poles is 689504Kg. About 861880kg. The weight of the truss is 451015kg heavier than the net frame, and the steel price is 4000 yuan/ton, and the cost of the net frame structure is about 1.8 million.

5. Construction Feasibility Comparison

In terms of construction, the space frame structure has better advantages than the truss structure. The truss structure requires high-altitude welding, and the quality requirements for the welds are relatively high. Relatively speaking, the workload is relatively large, and the safety requirements for personnel are relatively high. The falling of welding slag also poses safety hazards to the entry and exit of vehicles and personnel. The construction period long. The space frame structure can be welded on the ground, and does not require on-site construction and high-altitude operations. Finally, the overall hoisting method can effectively reduce the safety hazards of on-site construction and shorten the construction period.

6. Comprehensive comparison and suggestions

An optimal structural scheme should consider the comprehensive advantages, which should be convenient for construction and installation, cost saving, and reduce maintenance costs in the future. More importantly, it should save the construction period and improve the completion rate and efficiency. Compared with the scheme of space frame and truss, it is recommended that the roof of the terminal building adopt the space frame scheme. First of all, the overall weight of the truss is relatively high, and the construction is complicated. The rods of the truss need to be cut in advance according to the shape of the weld seam of each rod to be welded, and the cutting process is complicated. Secondly, the rigidity distribution of the truss structure is not uniform, and the lateral stiffness is small. It is necessary to set up supports to resist the longitudinal lateral force. High structural rigidity, good spatial integrity and good seismic performance. Finally, the truss structure transmits force in a plane, the internal force is uneven everywhere, and the specifications of the rods are inconsistent, so standardized production cannot be realized. The internal force distribution of the space frame structure is relatively uniform, and the space frame structure has been standardized in its rods, bolt balls, welding balls, cone heads, high-strength bolts, etc., which can save the construction period.                    

7. Conclusion

• For the two schemes of space frameand truss, it is recommended that the roof of the airport terminal building adopt the space frame
• The torsion-based vibration mode of the network frame appears the third-order vibration mode, which shows that the space frame is more rigid than the truss, and the torsional rigidity is greater.
• Compared with the truss, the spaceframe consumes less material and is more economical.

(4) The space frame rods can be produced in a standardized manner, and the construction is simple. The high-altitude bulk method and the overall hoisting method can be used, which is convenient for construction and saves the construction period. The truss requires on-site high-altitude operations, and the quality of the welds is high, and the construction period is long .