高速铁路大跨度低高度预应力混凝土连续梁设计研究

Research on Design of Long-span and Low Height Prestressed Concrete Continuous Beam of High-speed Railway

为降低铁路大跨度预应力混凝土连续梁高度,扩大其适用范围,提出主跨100 m低高度连续梁合理跨度配比及构造尺寸,计算结果均满足规范要求。通过与常用高速铁路主跨100 m连续梁对比分析,系统研究了跨度配合比、构造参数等对结构的影响,总结出大跨度低高度连续梁的优缺点及构造建议值。研究结果表明:(1)低高度连续梁在同等跨度下混凝土用量更省,每延米混凝土用量降低约20%,较传统连续梁更经济;(2)低高度连续梁由于梁高降低,主梁刚度略有降低,但工后徐变上拱值降低明显,减幅约60%;(3)对于主跨100 m低高度连续梁,建议配跨长度在70~80 m之间,且不宜小于60 m;(4)主跨100 m低高度连续梁墩顶梁高不宜小于6 m,建议取值范围6.0~6.5 m,跨中梁高不宜小于3.0 m,建议取值范围3.0~3.5 m。

In order To reduce the height of railway long span prestressed concrete continuous beams and expand their scope of application,this article proposes a reasonable span ratio and structural dimensions of a low height continuous beam with a main span of 100 m,and the calculation results meet the requirements of the specification.By comparing and analyzing the continuous beam with a main span of 100m in common high-speed railways,the effects of span mix ratio and structural parameters on the structure are systematically studied.The advantages and disadvantages of large span and low height continuous beams and the recommended construction values are summarized.The research results show that:(1)The concrete consumption of low height continuous beams is more economical compared to traditional continuous beams,with a reduction of about 20%per linear meter of concrete consumption with the same span;(2)Due to the decrease in beam height,the main beam stiffness of low height continuous beams has slightly decreased,but the creep camber value has significantly decreased after construction,with a reduction of about 60%;(3)For low height continuous beams with a main span of 100 m,it is recommended that the span length should be between 70 m and 80m,not less than 60 m;(4)The top beam height of a low height continuous beam pier with a main span of 100 m should not be less than 6m,and the recommended value range is 6.0 m to 6.5 m.The midspan beam height should not be less than 3.0 m,and the recommended value range is 3.0 m to 3.5 m.