Key Construction Technologies for Large-Span Tubular Trusses

Key technologies for large-span tubular truss construction include segmented lifting and temporary support. For trusses with spans exceeding 30m, it is advisable to use ground assembly + multi-crane lifting (e.g., coordinated operation of 4 x 75t truck cranes), and set up lattice-type temporary supports to ensure the accuracy of segmented connections. The supports must be reliably welded to the embedded parts of the main structure. During prestressing construction, computer simulation should be used to simulate the tensioning sequence, controlling the synchronous tensioning of 21 steel strands, and using dual control technology (primarily tension, with elongation value verification) to ensure uniform stress distribution in 70m-span structures.

For node installation, full penetration intersection welds should be prioritized. When extending steel pipes, the longitudinal weld stagger distance should be ≥5 times the wall thickness and ≥200mm. Large-span structures (such as 48m auditorium trusses) should be divided into 4 lifting units, using a combination of 80t truck crane loose assembly + overall lifting process, and cambering (≤1/300 of the span) should be set to compensate for deflection. During concurrent construction, the progress of civil engineering, mechanical and electrical, and other disciplines should be coordinated, and a 0.5m safety clearance should be reserved to solve the problem of lifting in narrow spaces.