摘要
针对低回缩预应力钢绞线体系应用于箱梁腹板的应力场计算设计了矩形薄板试验,对预应力即时损失以及矩形薄板各截面竖向预压应力场进行了测试。根据箱梁腹板在竖向预应力作用下的受力特点,利用竖向局部荷载作用下弹性力学平面应力问题的解析解,用多项式拟合得出应力扩散角、应力均匀度和名义应力度之间的计算公式。预应力损失测试结果表明,这种低回缩预应力钢绞线锚具的预应力即时损失值低于5%,从而证明了该体系应用于短索能有效地提高预应力效率,若应用于箱梁腹板能提高箱梁的抗剪可靠性。弹性理论计算结果与矩形薄板试验测得的竖向预应力作用下的应力场吻合较好,当扩散角α小于26.5°时,能保证各截面处于较高的应力水平和应力均匀度,表明了低回预应力钢绞线锚具应用于腹板竖向预应力时具有优越性。
For calculation of stress field when low retracting prestress stranded tendons system applied in web of box beam, a rectangular plate was fabricated to test the instantaneous prestress loss and vertical prestress fields of different cross-sections of rectangular plate were measured. According to the loading characteristics of web under vertical prestress, the stress of web was solved by the numerical computations based on the theory of the plane stress of elasticity under local vertical load, and the calculation formulas among the dispersion angle of stress, the uniformity of stress and nominal stress was derived by polynomial fitting accordingly. The result of the prestress loss test confirms that （1） the instantaneous prestress loss of the low retracting prestress stranded tendons anchorage is lower than 5%, which demonstrates that the new system used for short tendons can improve the prestress efficiency, and it also can enhance the anti-shearing capacity of box beam if it is used for the web of box girder.The calculation result based on the elastic theory is in good agreement with that of the experimental test on the stress field of rectangular thin ,plate prestressed with vertical tendons. The stress level and the evenness of each crosssection can be remained in favorite status when the dispersion angle is smaller than 26.5°, which proves that there is a fine prospect for the application of low retracting prestressed anchorage in vertical prestress system of web.
出处
《公路交通科技》
CAS
CSCD
北大核心
2009年第9期91-96,共6页
Journal of Highway and Transportation Research and Development
基金
广东省交通厅科技项目(200815)
关键词
桥梁工程
低回缩钢绞线锚具
矩形薄板试验
竖向预压应力场
扩散角
预应力损失
bridge engineering
low retracting prestressed anchorage
test of rectangular plate
vertical prestress field
dispersion angle
prestress loss
