双侧闭口型压型钢板混凝土组合构件轴压力学性能研究

Performance of Dovetail Profiled Steel Concrete Sandwich Composite Members Subjected to Axial Compression

双侧闭口型压型钢板混凝土组合构件由两侧放置的闭口型压型钢板和内部填充混凝土组成,内嵌于混凝土中的闭口型板肋既可作为钢板与混凝土之间的连接件,保证两者的共同工作,又能有效降低钢板的宽厚比,提高闭口型压型钢板的屈曲承载力。相比传统的双钢板混凝土组合构件,双侧闭口型压型钢板混凝土组合构件无需额外的连接件即可实现钢板和混凝土的共同工作,增加了施工的便利性和高效性,同时保持了双钢板-混凝土组合构件的性能优势,在工程中具有广阔的应用前景。采用有限元方法分析了闭口型压型钢板混凝土组合构件在轴压荷载作用下的受力全过程,包括混凝土截面的应力分布、压型钢板板带的应力发展过程及屈曲性能;通过试验结果和理论分析明确了板肋在混凝土中的嵌固作用;研究了压型钢板布置形式、混凝土强度等级、钢材屈服强度、钢板厚度(板带宽厚比)和构件厚度等参数对双侧闭口型压型钢板混凝土组合构件轴压性能影响规律。通过对双侧闭口型压型钢板混凝土组合构件受力全过程的分析,可以得到以下结论:闭口型板肋将压型钢板分成若干个板带,各板带单独发生受压屈曲,改变了钢板整体受压屈曲的方式;混凝土能够对嵌入的闭口型板肋提供足够的嵌固作用,使得压型钢板与混凝土能够共同工作;嵌入混凝土中的闭口型板肋为压型钢板板带提供了可靠的边缘嵌固和支撑,使得闭口型压型钢板仅在板带上发生局部弹性屈曲,且能够发展屈曲后强度,压型钢板板带的屈曲后强度可以采用有效宽度法计算;闭口型板肋嵌于混凝土中使得板肋附近混凝土的应力分布不均匀,并对两侧板肋之间的混凝土产生一定的约束作用,但截面上并未形成明显的约束区和非约束区;双侧闭口型压型钢板混凝土组合构件轴压承载力可由混凝土抗压承载力和考虑屈曲后强度的压型钢板承载力叠加获得;压型钢板布置方式对构件的轴压承载力没有明显影响,构件各组成部分的材料强度、墙体厚度和压型钢板厚度对其轴压承载力和延性影响明显。

Dovetail profiled steel concrete sandwich composite members(DPSC)are composed of two dovetail profiled steel sheets and filled concrete in between.The dovetail-shaped profiled ribs embedded in concrete can not only function as connectors for steel sheets and concrete,but also effectively reduce the steel sheet’s width to thickness ratio and improve the buckling capacity of steel sheet.Compared with the traditional double steel plate concrete composite member,the steel sheets and concrete of DPSC can work together without additional connectors,which increases the convenience and efficiency of construction,while maintaining the performance advantages of double steel plate concrete composite member,and has a broad application prospects in engineering.The mechanical response of the DPSC subjected to axial compression is analyzed by employing finite element method,the stress distribution of concrete section,the stress development process and the buckling behavior of the steel strips between ribs.Based on the above analysis,the embedment effect of rib in concrete is clarified.Finally,the influence of the positioning of the steel ribs,concrete strength grades,steel strength,sheet thickness(strip width to thickness ratio)and width of the members on axial compression performance of DPSC is analyzed.The following conclusions can be drawn through the analysis:the dovetail-shaped ribs divide the steel sheets into several strips to bear the axial compression load,and each strip develops the compression buckling wave independently,which changes the overall compression buckling mode of the steel plate;the infill concrete provides enough anchorage for the ribs to realize the composite action and make the steel sheets and concrete working together;the anchored ribs offer solid boundary support and anchorage for the steel strips,which lead the strips to full development of post-buckling strength;the post-buckling strength of the strips shall be considered in calculation of the DPSC bearing capacities;the anchored dovetail-shaped ribs,under axial compression,affect the concrete stress distribution nearby and cause some confinement for the concrete between two ribs,but there are no obvious constrained region and unconstrained region;the DPSC axial compressive bearing capacities can be evaluated by the summation of the concrete compressive capacity,steel ribs reaching yielding and the post-buckling strength of strips;the parameter analysis results show that the positioning of the steel ribs has no significant effect on the axial compression bearing capacity of the DPSC,however,the material strength,wall thickness and profiled steel plate thickness have significant effects on the axial compression bearing capacity and ductility.