"Afflictions" and "Remedies" of Wooden Arch Lounge Bridges

Investigation and Intervention of the Damage to the National Protected Site Shunde Bridge

Abstract

Wooden arch lounge bridges in Zhejiang and Fujian provinces represent a unique heritage in the history of world bridge engineering. Their preservation faces ongoing challenges from both natural and anthropogenic factors. Focusing on the Shunde Bridge, part of the Chuzhou Lounge Bridges in Longquan City, Zhejiang Province-a national key cultural heritage protection unit-this paper addresses its structural safety crisis. Through comprehensive literature review, on-site investigation, and 3D laser scanning technology, a systematic survey and diagnosis of the bridge’s damages were conducted. The results reveal major deteriorations, including severe decay and insect infestation of key structural members of the wooden arch (e.g., three-joint seedlings), overall tilting and tenon dislocation of the lounge timber frame, and persistent leakage due to roofing system damage. Based on an analysis of the causes-natural aging, biological erosion, and limitations of prior interventions-and adhering to the principles of authenticity, integrity, and minimal intervention in cultural heritage conservation, this paper argues that partial repairs are insufficient to ensure the safety and value preservation of the heritage structure in its current state. Consequently, a systematic conservation and restoration design centered on "complete dismantling and major repair" is proposed. This study aims to provide a direct basis for eliminating fundamental safety risks to Shunde Bridge, while also offering a referential case for the holistic conservation practice of similar wooden heritage structures-from refined diagnosis to scientific intervention.