Based on the simulating results of simply - supported box girders ( 39 . 1m ) and continuous box girders ( 2 x 40m ) , the paper emphatically analyzes the full mechanical characteristics of psbget and the bend failure states of the right section . the influence of different areas and eccentricities of external tendons on ultimate bearing capacity and ductility is studied in detail . the differences of ultimate bearing capacity and the mechanical characteristics between the se Lin简支箱梁和2x40m连续箱梁为例，本文较全面地分析了预制节段拼装体外预应力混凝土箱梁全过程受力特性和正截面弯曲破坏形态；研究了不同预应力配筋面积和预应力筋重心高度对预制节段拼装体外预应力简支梁极限承载力和延性的影响，以及体外预应力节段简支梁与体外预应力、体内有粘结预应力整体简支梁极限承载力和受力特性的差异。
In the thesis , 3d finite element , models ( fem ) of the precast segmental box girders are established with contact elements , which may simulate the interactions between the joints . the influences of material nonlinearity of concrete and geometric nonlinearity of structure are also taken into account in the computed models 针对预制节段干接缝拼装梁存在接缝的特点，采用接触单元模拟接缝间的相互作用，解决了预制节段拼装梁建模的关键问题，并在计算模型中考虑了混凝土材料非线性和结构几何非线性的影响。
