Research On Inspection And Assessment Of Existing Medium And Mini-Sized Span Arch Bridge

A lot of stone arch bridges and two-way curved arch bridges were built in our country in 1960th-1970th, because economic condition and technique level were limited. The stone arch bridge can use local materials, the material source is extensive and the fabrication cost is low. The two-way curved arch bridges which constructed without arch falsework have advantages of prefabricate and assemble, accordingly, the timber is saved, the construction speed is accelerated, the use of labor and materials is reduced, and the national condition of our country at that time is also accorded with. Therefore, a lot of medium and mini-sized span arch bridges were built at that time. Because construction technology was relatively backward at that time, and the overload phenomenon is comparatively serious at present, so there are damages in various degree after operation for many years. In order to guarantee the operation safety and provide a reliable basis for maintenance and reinforcement, we must inspect and assess these kinds of bridges, and evaluate their load-carrying capacity.This paper mainly research into the detection techniques and assessment method of medium and mini-sized span arch bridge. The detection techniques include applying modern technology to inspect the appearance and material state which is aim to confirm the actual condition of the bridge and offer the reliable information for the following assessment work. Besides, various existing assessment methods are introduced, and several common assessment method are researched systematically. The assessment method which depends on the appearance is discussed first, and then the load-carrying capacity assessment method with analyzing and calculating, and the assessment method by load testing etc. are introduced as well. And the application of the assessment method for medium and mini-sized span arch bridge is studied deeply.Furthermore, the attenuation and cause of resistance of medium and mini-sized span arch bridges are studied to a certain degree, and then various influences including materials decay, structural innate defect and historical limitation of building period, etc. are probed into, thus the understanding of structural function changing and analysis of disease causes are strengthened in the assessment.Finally, this paper carries on systematic analyzes of detection and assessment with two assessment case of stone arch bridges and two-way curved arch bridges, the existing disease of bridges is analyzed by the inspect of appearance and material state, and their real load-carrying capacity are confirmed by modeling and calculating the structure through introducing the calculating coefficient and structural damage, and then the real technological state of the bridges are confirmed by two kinds of methods: assessment of synthetically appearance and analyze calculating method, therefore, a reliable basis for maintenance and strengthening is provided reliably.