1. The fastener specifications need to be the same as the outer diameter of the steel pipe.
2. The tightening torque of fastener bolts should not be less than 40N.m and not more than 65N.m.
3. At the main node, the distance between the center line of fasteners such as large and small crossbars, scissor supports, and lateral supports should not be greater than 150 mm from the main node.
4. The opening of the fastener should face upward or inward.
5. The length of the end of the rod extending beyond the edge of the cover of the fastener is not less than 100mm.