Monitoring Method for the Self-Bearing Process During the Construction of Long-Span Steel Roof Structures with Ring Beams

Long-span steel roofs with spatial ring beams as their primary load-bearing elements are widely adopted in large stadiums and public facilities. Their construction involves complex stages—ring beam assembly, closure and staged falsework unloading—during which boundary conditions, internal forces and overall stiffness change considerably. This study proposes a stiffness monitoring method that evaluates the self-bearing process of such structures based on measured stress and displacement data. The method establishes a stiffness matrix for different construction stages and introduces an indicator of stiffness change rate to quantify stiffness evolution during unloading. To validate this approach, finite element method simulations were conducted, and their predictions were compared with monitoring data from the Shenzhen Stadium steel roof. The monitored and simulated stiffness variation trends show strong agreement, thereby validating the applicability of the proposed monitoring framework. The method enables real-time tracking of structural safety, supports optimisation of the unloading sequence and enhances our understanding of stiffness evolution during construction. Overall, this study presents a validated, data-driven framework for monitoring and optimising the self-bearing process of long-span steel roof structures, thereby improving both construction safety and service performance.