Curved Truss Design for Arched Roof Truss

The optimization of wind load resistance of aluminum alloy curved roof trusses needs to be promoted in a coordinated manner from three aspects: structural design, aerodynamic shape and node reinforcement. The specific measures are as follows:

1. Aerodynamic shape and structural topology optimization

Refined design of arc curvature: By adjusting the arch height ratio (f/L) through CFD simulation, when the curvature radius R=1.5L, the wind pressure coefficient can be reduced from 1.2 to 0.8. The truss of a coastal gymnasium uses a 1:5 arc height ratio. Wind tunnel tests show that the negative pressure area is reduced by 30% and the equivalent wind load is reduced by 25%.

Additional guide components: Adding a 100mm×50mm aluminum alloy guide plate on the outside of the truss upper chord can move the separation vortex area back 2m, which reduced the amplitude of the pulsating wind load by 18% in a commercial dome. Installing curved edge banding at the eaves can eliminate the local negative pressure peak (from -1.5kPa to -1.0kPa).

2. Strengthening structural rigidity and node strength

Optimization of chord section: Using a box section (such as 200mm×150mm×8mm ) instead of an I-shaped section, the out-of-plane stiffness is increased by 40% . A dome truss in a typhoon area increased the chord moment of inertia from 0.012m⁴ to 0.018m⁴ , and the wind vibration displacement was reduced from 58mm to 32mm (meeting the L/400 limit).

Node rigid connection design: Use cast aluminum nodes (such as A356-T6) instead of bolt splicing, and the node rigidity is increased by 60%. After a certain airport dome truss was switched to cast aluminum nodes, the node rotation angle under wind load was reduced from 0.02rad to 0.008rad, avoiding overall instability caused by node deformation.

3. Wind vibration control and material selection upgrade

Tuned mass damper (TMD) configuration: A TMD with a mass of 0.5% of the structure (frequency 2.5 Hz) was installed in the mid-span of the truss. The amplitude of the wind-induced vibration response of a large-span dome (L=60m) was reduced from 120mm to 45mm, which is lower than the code limit (L/500=120mm).

Application of high-strength aluminum alloy: The main components use 7075-T6 aluminum alloy (σb=572MPa) instead of 6061-T6. The stress ratio of truss members in a coastal project was reduced from 0.85 to 0.62, and the safety factor against typhoons (level 17) was increased from 1.8 to 2.5.

4. Wind load calculation and measurement verification

Powerful Solutions For Aluminum circle truss

Refined analysis of dynamic wind loads: Considering the terrain roughness (Class B topography) and turbulence, the basic wind pressure of a commercial dome in a city is calculated as 0.55 kPa according to the Code for Loads on Building Structures GB 50009-2012. After adding the pulsating wind coefficient of 1.6, the design wind pressure reaches 1.2 kPa, which is 35% higher than the static calculation.

Pre-buried wind pressure monitoring system: wind pressure sensors are arranged on the upper chord of the truss. The measured data of a certain exhibition center shows that the maximum wind pressure during the typhoon is 1.05kPa, which deviates from the design value by less than 5%, verifying the effectiveness of the optimization scheme.

 

Project case: A tropical island tourist center adopted the above optimization measures (arc-height ratio 1:4.5 + cast aluminum nodes + 7075 profiles) and passed the test of a 17-level typhoon (wind speed 56m/s). The maximum displacement of the structure was 42mm (L/600), far below the specification limit, and there was no node damage or rod buckling. This type of optimization significantly improves the safety of aluminum alloy trusses in typhoon areas and coastal areas.

If you need high quality aluminum curved roof trusses , please contact Shizhan for more questions.