Axial Compressive Properties of Prefabricated Circular Steel Tube Confined Concrete Columns
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摘要: 为了研究钢套管及套筒连接装配式圆钢管约束混凝土柱轴压性能,基于试验研究结果,对钢套管及套筒连接装配式圆钢管约束混凝土柱轴压性能进行了有限元分析. 首先通过有限元建立了现浇式和装配式圆钢管约束混凝土柱模型;然后从承载力-平均纵向应变关系曲线、钢管应力、钢筋应力和混凝土应力方面对比了现浇式与装配式柱的轴压性能;其次分析了装配式柱变形形态及受力机理;最后提出了装配式柱轴压承载力计算方法. 研究结果表明:与现浇式柱相比,装配式柱也具有良好的轴压性能和延性性能,钢管及钢套管对核心混凝土的约束作用更强,轴压承载力提高幅度为1.94%~6.17%;增加钢管厚度对提高装配式圆钢管约束混凝土柱轴压承载力最有效,提高幅度达59.15%,增加箍筋间距对其轴压承载力影响较小,减小幅度为2.91%;钢管纵向应力在靠近钢套管与钢管连接处较大,钢管环向应力在钢管通缝上、下附近区域较大,在钢套管装配处也较大;所提装配式柱轴压承载力公式计算值(Nuc)与有限元值(Nuf)、试验值(Nut)的比值均值分别为0.964、1.014,方差分别为0.003 5、0.002 9.
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关键词:
- 装配式圆钢管约束混凝土柱 /
- 钢套管 /
- 应力 /
- 轴压承载力 /
- 计算方法
Abstract: A finite element analysis based on test results was carried out to study axial compressive performances of the prefabricated circular steel tube confined concrete columns connected with steel sleeve and straight thread sleeve. First, finite element models of cast-in-situ and prefabricated circular steel tube confined concrete columns were established. Then, axial compressive performances of the cast-in-situ and prefabricated columns were compared in terms of the bearing capacity–average longitudinal strain curves, steel tube stress, rebar stress, and concrete stress; the deformation pattern and mechanism of prefabricated columns were analyzed. Finally, a calculation method of axial compressive capacity of prefabricated columns was proposed. Results show that the cast-in-situ columns and the prefabricated columns both have good mechanical and ductility properties; the steel tube and steel sleeve have strong confinement effect on the core concrete and the axial compressive bearing capacity was increased by 1.94%−6.17%. Increasing the thickness of steel tube can effectively improve the axial compressive bearing capacity by 59.15% at most, while increasing the stirrup spacing has little effect on the axial compressive bearing capacity, merely a reduction of 2.91%. The longitudinal stress of the steel tube is larger in the area near the connection between the steel tube and steel sleeve, while the circumferential stress of the steel tube is larger in the area near the upper and lower circular sutures of steel tube and is also larger at the assembly of steel sleeve. The average ratio of calculated value (Nuc) to finite element value (Nuf) and the average ratio of Nuc to test value (Nut) is 0.964 and 1.014, with variance of 0.003 5 and 0.002 9, respectively, where Nuc, Nuf and Nut denote respectively the values from formula calculation, finite element calculation, and test of the prefabricated column axial compressive bearing capacity. -
表 1 试验试件参数及轴压承载力
Table 1. Parameters and axial compressive bearing capacity of test specimens
试件编号 试验试件尺寸
(D1、t1、L1)/mm钢套管尺寸
(D2、t2、L2)/mm套筒尺寸
(D3、t3、L3)/mm纵筋/mm 箍筋/mm λ 混凝土
强度等级轴压承载力/kN Nut Nuf Nuc S-FCTRC1 200、1.5、1 200 203、1.5、120 25、2.5、34 620 ϕ8@200 24 C50 2 746 2 904 2 801 S-FCTRC2 240、1.5、1 440 243、1.5、120 25、2.5、34 620 ϕ8@200 24 C50 3 456 3 641 3 535 S-FCTRC3 200、1.5、2 000 203、1.5、120 25、2.5、34 620 ϕ8@200 40 C50 2 633 2 718 2 552 S-FCTRC4 240、1.5、2 400 243、1.5、120 25、2.5、34 620 ϕ8@200 40 C50 3 480 3 466 3 221 S-FCTRC5 210、3.0、630 216、3.0、120 19、2.5、34 414 ϕ8@200 12 C50 2 846 3 095 3 018 S-FCTRC6 210、3.0、630 216、3.0、120 19、2.5、34 414 ϕ8@200 12 C80 3 785 4 090 4 121 CTRC-200-6-0A 200、1.5、1 200 200、0、120 25、0、34 620 ϕ8@200 24 C50 2 667 2 820 CTRC-240-6-0A 240、1.5、1 440 240、0、120 25、0、34 620 ϕ8@200 24 C50 3 366 3 546 CTRC-200-10-0A 200、1.5、2 000 200、0、120 25、0、34 620 ϕ8@200 40 C50 2 480 2 560 CTRC-240-10-0A 240、1.5、2 400 240、0、120 25、0、34 620 ϕ8@200 40 C50 3 414 3 400 c-210-3-50-a-235 210、3.0、630 210、0、120 19、0、34 414 ϕ8@200 12 C50 2 780 3 023 c-210-3-80-a-235 210、3.0、630 210、0、120 19、0、34 414 ϕ8@200 12 C80 3 710 4 008 表 2 有限元模型参数及轴压承载力
Table 2. Parameters and axial compressive bearing capacity of finite element models
有限元模型编号 有限元模型尺寸
(D1、t1、L1)/mm钢套管尺寸
(D2、t2、L2)/mm套筒尺寸
(D3、t3、L3)/mm纵筋/mm 箍筋/mm λ 混凝土强度等级 轴压承载力/kN Nuf Nuc FCTRC1 190、5、600 200、5、120 21、2.5、34 616 ϕ8@70 12.6 C30 3 023 2 855 FCTRC2 190、5、600 200、5、120 21、2.5、34 616 ϕ8@70 12.6 C50 4 065 3 592 FCTRC3 190、5、600 200、5、120 21、2.5、34 616 ϕ8@70 12.6 C80 4 181 4 660 FCTRC4 190、5、600 200、5、120 15、2.5、34 610 ϕ8@70 12.6 C30 2 827 2 626 FCTRC5 190、5、600 200、5、120 27、2.5、34 622 ϕ8@70 12.6 C30 3 264 3 214 FCTRC6 190、5、600 200、5、120 21、2.5、34 616 ϕ8@100 12.6 C30 2 935 2 855 FCTRC7 190、5、600 200、5、120 21、2.5、34 616 ϕ8@160 12.6 C30 2 864 2 855 FCTRC8 190、5、1 200 200、5、120 21、2.5、34 616 ϕ8@70 25.3 C30 2 632 2 738 FCTRC9 190、5、2 400 200、5、120 21、2.5、34 616 ϕ8@70 50.5 C30 2 414 2 269 FCTRC10 184、2、600 194、5、120 21、2.5、34 616 ϕ8@70 13.0 C30 2 060 1 991 FCTRC11 200、10、600 220、5、120 21、2.5、34 616 ϕ8@70 12.0 C30 4 811 4 107 FCTRC12 190、5、600 194、2、120 21、2.5、34 616 ϕ8@70 12.6 C30 2 751 2 855 FCTRC13 190、5、600 210、10、120 21、2.5、34 616 ϕ8@70 12.6 C30 3 249 2 855 FCTRC14 180、0、600 190、5、120 21、2.5、34 616 ϕ8@70 13.3 C30 1 426 1 313 FCTRC15 184、2、600 184、0、120 21、2.5、34 616 ϕ8@70 13.0 C30 1 926 1 991 FCTRC16 180、0、600 184、0、120 21、2.5、34 616 ϕ8@70 13.3 C30 1 361 1 251 -
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