Mountain Torrent Damage Mechanism And Risk Assessment Of Highway Bridges In Qinba Mountain

Qinba Mountain is located in the central and western regions in China, where rainfallis rich, and geological disasters always occur. Highway bridges are often damaged bymountain torrents, landslides, collapse and mudslides. Highway bridges in mountainous areaalways the arch bridges and girder bridges with medium or small span, and how to make thesetypical mountainous bridges prevent from mountain torrents and formulate the correspondingmaintenance management measures become to key aspect to ensure the bridge safety. In orderto improve the anti-mountain torrents resistance of highway bridges, it is of great significanceto survey the mountain bridge disaster kinds, highway bridge failure mechanism of mountaintorrents, maintenance measures and so on.In this paper, a typical highway masonry arch bridge is selected of Qinba mountains,through the analysis of the natural environment of Qinba mountains, and combining with thehighway bridges damage accident of mountain torrent disaster, damage mechanism andmaintenance strategy are studied, the main research work are as following:(1) Summarizes the types and characteristics of highway bridges in mountain area,reviews the mountainous bridges damaged accidents by mountain torrents, and brieflyanalyzes the cause of the damaged accidents; studies the research progress of mountainousbridges of mountain torrents in China and other countries;(2) Analyzes the landform, climate features, hydrological characteristics, vegetativecover and soil characteristics of Qinba Mountain Area; briefly introduces the mountaintorrents and other geological disasters and the threat to highway bridges; studies the highwaybridge damage types of mountain torrent and the main influence factors;(3) Conducts the research on damage failure mechanism of highway bridges due tomountain torrent in Qinba Mountains area, studies the mechanical performance of the bridgewhen the mountain torrent occurs; based on a typical mountainous area highway bridge, thestructure forces of the bridge in mountain torrents is calculated, the safety condition and theinfluence factors are evaluated;(4)In order to study the damage risk of mountain torrent and other concurrent disasters,highway bridge damage risk evaluation model of Qinba Mountains area is established,through the expert investigation method to calculate different risk factors, uses analytichierarchy process (AHP) and fuzzy mathematics theory (FMT) to assess the damage risk ofmountain torrent, and the risk index is calculated;(5) Based on the research results, combines with the climate and geology characteristics, preventive maintenance and regularly maintenance strategies for highwaybridges in mountainous area are given, which provides technical support for highway bridgessafety operation in Qinba Mountain Area, and provides the references for highway bridgemaintenance in other areas.