摘要
本文通过３０片部分预应力混凝土（ＰＰＣ）约束箱梁（其中９片为无箍筋，２１片为有箍筋）的抗剪试验，分析了具有反弯点的箱梁斜截面抗裂特性；指出了箱形“框架效应”、两侧腹板受力不均和宽度尺寸偏差对第一条斜裂缝的产生、开展具有的明显影响；讨论了造成约束箱梁斜裂缝开裂剪力比简支梁降低的原因；指出现行《铁路桥规》（ＴＢＪ２─８５）中斜截面抗裂性计算公式对ＰＰＣ约束箱梁、连续箱梁是不安全的；提出了考虑平均预应力度和剪跨比ｍ影响的约束箱梁斜截面开裂剪力计算公式，其试验结果与计算值吻合较好。
Based on the test results of 30 PPC restrained box girders (9 without stirrupsand 21 with stirrups), the characteristics of diagonal cracking of box girders with inflexionpoints are analyzed. It's indicated that the initial inclined crack formation and propagationare affected by the“effect of the box frame”, unequal shear forces carried by two webs andthe manufacturing deviation of web widths.The reasons that why the diagonal crackingshear of restrained box birders is lower than that of simple T-beams are discussed.It is unsafe to predict the diagonal cracking shear of PPC restrained box girders by using the formulain the《Railway Bridge Design Code》 (TBJ2-85). The calculated value from formulae presented in this paper considering effects of the average degree of prestressing (λ) and shear-span ratio (m) agree well with test ones.
出处
《铁道学报》
EI
CSCD
北大核心
1994年第1期87-93,共7页
Journal of the China Railway Society
基金
铁道部建设司基于可靠性理论修改<铁路桥规>科研专题
关键词
约束箱梁
斜截面
抗裂性能
混凝土
restrained box girder,partially prestressed concrete,diagonal cracking behaviour, average degree of prestressing
