狭窄地形条件下旧路加宽改造方案研究

Study on Road Widening and Reconstruction Scheme under Narrow Terrain Conditions

在公路改扩建工程中,建设方案必须充分考虑周边地形限制、既有建筑物的结构等因素的影响。地形受限采用路基加宽方案不易实施时,往往采用桥梁方案进行横向加宽。以山西省内某改扩建工程为背景,通过既有道路现状调查、桥梁上部和下部结构形式及施工方法的对比分析,确定了在现有狭窄地形条件下,采用半路半桥的拓宽设计方式。为保证桥下净空及右侧既有堤坝的安全,采用非对称预应力混凝土悬臂盖梁和大悬臂预应力混凝土盖梁设计方案进行对比研究。通过对加宽方式选择及悬臂预应力混凝土盖梁设计思路、计算方法的阐述,验证了该设计思路的合理性,更确保了施工的安全性,可为同类改扩建工程桥梁方案的设计分析提供相关经验。

In highway reconstruction and expansion projects,the construction scheme must fully consider the influence of surrounding terrain restrictions,the structure of existing buildings,and other factors.When the subgrade widening scheme is not easy to implement because of terrain restrictions,the bridge scheme is usually used for transverse widening.Based on a reconstruction and expansion project in Shanxi Province,through the investigation of existing road status,and comparative analysis of the forms and construction methods of bridge superstructure and substructure,the half-road half-bridge widening design is determined to be adopted under current narrow terrain condition.To ensure the clearance under the bridge and the safety of the existing dam on the right side,two schemes,the asymmetric prestressed concrete cantilever girder,and large cantilever prestressed concrete bent cap,are compared and analyzed.Based on the widening scheme selection and the statement of the design concept and calculation method of the cantilever prestressed concrete bent cap,the reasonability of this scheme is verified,and the construction safety is ensured.This paper can provide relevant experience for the design and analysis of bridge schemes for similar reconstruction and expansion projects.