This construction method is designed for installing large-span arched steel structures in both industrial and civil building engineering projects. It is particularly well-suited for civil engineering works where the main structure consists of concrete frame beams and slabs, topped with a large-span arch steel structure.
Process Principle
The main arch is installed using segmented fabrication, transportation, and assembly to meet both design and transportation requirements. To maintain the overall spatial structure’s stability, the main arch installation must be coordinated with the installation of other structural beams. The installation sequence starts at the four main arch feet and proceeds upward, closing at the arch’s apex. Simultaneously, the tie rod supports between the main arch and the roof arch are installed promptly.
Construction Process and Key Points
1. Process Flow
Establish measurement control network and measurement control → Design main arch support frame → Main arch hoisting and installation → Unloading
2. Key Operation Points
Installing large-span steel arches involves several critical steps, such as selecting the appropriate sections and cranes, precise construction measurement and positioning, installing support structures, lifting and installing the steel arches, and unloading. Among these, the lifting and installation of the steel arches is the most crucial phase.
2.1 Establishing a Measurement Control Network and Measurement Control
1. Handover and Review of GPS Points
Based on GPS point data, a verification process is conducted to ensure point accuracy. The specific measurement steps include setting up a secondary control network aligned with the GPS point layout across the construction area. The accuracy of this network is calculated using the closed traverse observation method. If the GPS accuracy meets construction requirements, the points can be used; otherwise, adjustments must be made before proceeding. Additionally, benchmark points are re-examined following national second-level benchmark standards. Several fixed benchmark points are established in the construction zone, where joint measurements are performed to ensure accuracy.
A construction control network is then established, featuring axis control piles to create a unified layout (see figure below).
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