广州地铁14号线全刚构桥梁设计关键技术

根据广州地铁14号线高架线桥梁景观和绿色建造的总体设计目标,全线标准段采用4×40m无支座单薄壁墩连续刚构桥、预制节段拼装施工的绿色建造技术。为适应温度及收缩徐变作用,桥梁根据桥高调整联长及跨度。设计研究确定分离边墩连续刚构桥梁刚度标准、节段拼装桥梁强度验算方法;通过先简支再连续后固结的成桥工序,释放预应力二次力对边墩的作用。斜跨路段采用大跨度曲线Y形刚构桥,有效降低大跨度桥梁梁高;薄壁边墩后固结,改善梁端刚度。上部结构Y形三角刚架区采用满堂支架或钢管支架施工,通过控制支架刚度,避免施工阶段次内力锁定在斜腿刚构内,保证初始线型满足设计要求。

Key Technology of the Full-rigid Frame Bridge for Guangzhou Metro Line 14

According to the overall design goals of the bridge landscape and green construction of the elevated line of Guangzhou Metro Line 14, a continuous rigid frame bridge with a span of 4 × 40 m is designed, with non-load-bearing single thin-wall piers along the entire length and a large-span Y-type rigid frame bridge. A segmental assembling method is adopted to construct the environmentally sustainable technology. In order to compensate for the effect of temperature, shrinkage, and creep, the length and span of the bridge can be adjusted. The rigidity standard and design method of the segmental concrete bridge are pre-determined according to research. The effect of the pre-stressed secondary force on the side pier is released by the bridge-forming process, which is simply supported and then consolidated. The large-span curve Y-type rigid frame bridge is adopted in the inclined span section, such that the beam height of the large-span bridge is effectively reduced; after the thin-wall side pier is fixed, the rigidity of the beam end is improved. The Y-shaped triangular rigid frame area of the upper structure is constructed using a full-hall bracket or steel pipe support, the rigidity of the bracket is controlled, and the secondary internal force of the construction stage is prevented from being locked in the inclined leg rigid frame, such that the initial line type meets the design requirement.