城市地下枢纽综合体大跨钢-混组合结构关键技术研究——以深圳市岗厦北枢纽为例

Research on Key Technologies for Long-Span Steel-Concrete Composite Structures in Urban Underground Hub Complexes-A Case Study of Gangxia North Hub in Shenzhen

为研究钢-混组合结构在城市地下枢纽综合体应用的关键技术,以深圳市岗厦北枢纽核心换乘区中庭48 m×51.2 m范围无柱钢-混组合大跨结构为背景建立三维增量有限元模型,从总体设计原则、受力特性、构造细节、防腐设计等方面展开研究。通过计算分析、模型试验、地下大跨钢结构防腐方案比选得到以下结论。(1)基于梁格布置和梁上反弯点的位置确定负弯矩区混凝土板的分布范围,计算分析时仅考虑有效宽度范围内受拉钢筋的刚度和顶板自重;采用高配筋法进行配筋设计,抗裂性能满足规范要求,无需设置预应力束;在梁柱节点附近顶板内设置构造钢筋进行局部加强。(2)借助缩尺模型试验和局部有限元分析验证了新型梁柱节点的承载能力。(3)综合考虑适用环境、防腐工艺、计算分析以及景观效果选用钢结构涂装养护方案,并根据钢箱梁不同部位所处的环境情况提出针对性的防腐措施。

To investigate the key technologies of the application of steel-concrete composite structures in urban underground hub complexes,a three-dimensional incremental finite element model was established for the columnless long-span steel-concrete composite structures within an area of 48 m×51.2 m in the core transfer area of Gangxia North Hub in Shenzhen.The overall design principle,mechanical characteristics,structural details,and anti-corrosion design were studied.Through computational analysis,model testing,comparison and selection of anti-corrosion schemes for underground long-span steel structures,the following conclusions were drawn:(1)The distribution range of concrete slabs in the negative bending moment area was determined based on the beam lattice layout and the position of the reverse bending point on the beam.Only the stiffness of the tensile reinforcement and the dead weight of the roof in the effective width were considered in the calculation and analysis;The high reinforcement method was used for reinforcement design,achieving cracking resistance that met the code requirements,without the need for prestressing tendons.Structural reinforcement bars were arranged in the roof near the beam-column joint for local strengthening.(2)The bearing capacity of the new-type beam-column joint was verified through scale model testing and local finite element analysis.(3)Considering the applicable environment,anti-corrosion process,analysis,and landscape effects,the steel structure maintenance and coating plan was selected.Targeted anti-corrosion measures were proposed based on the environmental conditions of different parts of the steel box girder.