Small Towns Adaptability Typical Bridge Type Study

Associated to the sub-project "Research of key technology of traffic and road construction in small town"(2003BA808A15-1) of the Tenth Five-Year Critical Research project "Key technology of infrastruction construction in small town ", the research of adaptable typical bridge in small town is carried out in this paper.Based on large quantity of investigation and study of bridges in small town and comprehensive collection of existing research documents in and beyond the country, the fundamental statement of bridges in small town is generalized in this paper. At the same time, the present main problems of bridges in small town are pointed out. According to the characteristic of small town, the factors such as regional differences, economy, function, safety, landscape and environmental protection that affect the selection of bridge type in small town are analyzed. Based on those factors, the adaptable bridges, the types of bridge pier and abutment as well as common types of affiliated facilities for small town are put forward.The paper chooses two kinds of typical bridge whose span is over 20m in small town as objects for research, such as reinforced concrete truss arch bridge and reinforced concrete rigid frame bridge. It studies their mechanical characteristics, structural features and construction methods. Moreover, parameter analysis of rise-to-span ratio of truss arch bridge with oblique tension link and span ratio of slant legged rigid frame bridge are carried out in four kinds of span which are 20m, 30m, 40m and 50m. The result shows that the inner force of all critical sections of both PC truss arch bridge and PC rigid frame bridge have uniform change tendency with the variation of parameters for those four kinds of spans.At last, Effective measures of maintenance and management of small town bridge for current common disease of several kinds of small town bridges are put forward.The research result in this paper paves way to the further study of small town bridge. It has great value for the promotion of small town bridge development.