【摘要】 为了消除"折点"效应,改善折线配筋先张梁弯起器部位钢绞线的应力状态,选用优选半径R=600 mm为导向半径,采用导向构件与支撑心轴的组合构件代替原导向辊,设计并研制了构造简洁、拼装灵活的新型折线配筋先张梁弯起器。为了研究新型弯起器对钢绞线力学性能的改善作用,采用试验方法,研究了采用不同导向半径R及不同弯折角度θ时,弯起器对钢绞线极限强度、延性性能的影响规律,并深入分析了试验现象与影响规律的产生机理。试验结果表明:随着R的增大钢绞线强度与延性性能的折减效应呈对数曲线趋势减小,当R≥100 mm时,R与θ的变化对钢绞线力学性能的影响较小;说明弯起器导向半径R在满足结构尺寸与构造要求前提下应尽量取大值,受限时也不宜小于100 mm,从而验证了新型弯起器的科学性。更多还原

【Abstract】 In order to eliminate the harmful effects of inflection point and improve the stress state at the bending component of steel strand of polyline pretensioned beam(PPSCB),a new bending component of PPSCB,whose structure is simple and easy to assemble,is developed.The new bending component is based on the roller bending component,the roller is replaced by a combined member constituted by a guiding device and two mandrels,and the optimized radius R=600 mm.The experiment is designed to study the influence of the new bending component on the mechanical property of steel strands.The regularity and the mechanism of the ultimate strength and ductility of steel strands affected by the radius R and the bending angle θ is analyzed.The result shows that(1) with the increase of R,the reduction effect of the ultimate strength and ductility of steel strands decrease which conforms to the rule of logarithmic function;(2) when R≥100 mm,the mechanical property of steel strand is less affected by the variation of R and θ.It indicates that the radius of the bending component should be as large as possible when the dimensions of bend component meet the structure and configuration requirement,and it should not less than 100 mm when the size is limited.Thus the scientific nature of the new bending component is confirmed.更多还原