1 115 Key words multi-cavity CFST pentagonal cross-sections mega-columns eccentric compressive behavior numerical simulation 117 T L 1 T T T 2 3 L L 4

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1 JOURNAL OF NATURAL DISASTERS Vol. 24 No. 1 Feb DOI: /j. jnd CF - Ⅰ CF - ⅡCF - Ⅰ CF - Ⅱ 2 - ABAQUS TU375 A Calculation analysis of eccentric compression behavior of pentagonal CFST mega columns CAO Wanlin XU Mengmeng WU Haipeng DONG Hongying College of Architecture and Civil Engineering Beijing University of Technology Beijing China Abstract Taking the pentagonal multi-cavity concrete filled steel tubular CFST mega-columns of Dalian International Trade Center building as the prototype eccentric compression performance tests of two mega-column models with different cross-section constructions were carried out in order to investigate the influence of cross-section construction on eccentric compression behavior. Specimen CF-I was a CFST mega-column model with pentagonal quadruple-caved section without reinforcement cage inside and Specimen CF-Ⅱ was that with reinforcement cages inside. The load-bearing capacity load-deformation curves and failure characteristics of two models were obtained and the finite element simulation was carried out based on ABAQUS as well. The results of simulations accord well with the test. In view of this simulations are carried out for analyzing the effects of the thickness of the external steel tubular plates the separator located in the axis of asymmetry and peripheral vertical ribs on eccentric behaviors of columns. The conclusions are drawn that the additional reinforcement cages can improve load-bearing capacity and ductility the increased proportion of bearing capacity and ductility due to the increase of thickness of external plates is greater than that due to the increase of thickness of separator located in the axis of asymmetry and that the damage of specimens are reduced by increasing the thickness of surrounding vertical ribs wlcao@ bjut. edu. cn

2 1 115 Key words multi-cavity CFST pentagonal cross-sections mega-columns eccentric compressive behavior numerical simulation 117 T L 1 T T T 2 3 L L 4 ANSYS 5 6 L /5 2 CF - Ⅰ CF - Ⅱ CF - Ⅰ % CF - Ⅱ CF - Ⅰ 9Φ6 φ4@ 80 CF - Ⅱ 0. 29% 3000 mm mm 250 mm mm 1 Fig. 1 1 Design drawing of specimens Q345 C MPa MPa 1 1

3 F y F u ρ E Table 1 1 Mechanical properties of steels F y /MPa F u /MPa ρ /% E /MPa 6 mm mm mm φ4 Φ CF - Ⅱ CF - Ⅱ t kN 2 Fig. 2 2 Photo of test site % CF - Ⅰ CF - Ⅱ 3 Fig. 3 Failure modes of specimens

4 F - U CF - Ⅰ kN CF - Ⅱ kn CF - Ⅱ CF - Ⅰ 7. 3% CF - Ⅱ CF - Ⅰ Fig Curves of vertical load vs lateral deflection 5 CF - Ⅰ CF - Ⅱ 5 a Fig. 5 - Load - strain curves f Z % ABAQUS damaged plasticity

5 Fig. 6 6 Lateral deflection distribution 9 - μ 9 ζ x = ε y = σ ε 0 σ 0 x 1 y = 2x - x 2 x > 1 y = σ 0 = μ μ 24 f' 1 x β( x - 1) η + x [ ( ) ] [ ( ) ] c 45 f' c 3 ε 0 = f' c f' c 24-1 μ η = /x β = f ' c 槡 μ. 6 μ = A s1 f y1 + A s2 f y2 CF - Ⅰ μ = CF - Ⅱ μ = A c f ck f y1 f y2 A s1 A s2 A c f ck f ck = f cu k f' c f c ' = 0. 79f cu k f cu k ABAQUS Plasticity - - Tie embed 8 C3D8R S4R T3D2

6 CF - Ⅰ CF - Ⅱ - Table 2 2 Calculated and experimental results of ultimate bearing capacity of specimens /mm CF - Ⅰ CF - Ⅱ F u /kn N u /kn N u /F u Fig. 7 7 CF - Ⅰ Calculated and experimental results of Specimen CF - Ⅰ Fig. 8 8 CF - Ⅱ Calculated and experimental results of Specimen CF - Ⅱ mm 12 mm 12 mm mm mm

7 Fig Fig. 9 9 Comparison of skeleton curves CF - Ⅰ Calculated results of specimen CF - Ⅰwith different thicknesses of outer pipes Fig CF - Ⅱ Calculated results of specimen CF - Ⅱwith different thicknesses of outer pipes 10 mm 8 12 mm mm 6 mm 6 mm 4 mm 6 mm - 13

8 曹万林 等 五边形钢管混凝土巨型柱偏压性能计算分析 CA w M w E w O.c 凯 am 模 eo CA.o E案 rg.c 例库 n 第1 期 图 12 Fig 12 不同对称轴分腔隔板厚度试件计算结果 Calculated results of specimens with different thickness steel axis of symmetry 图 13 Fig 13 不同周边竖向肋板厚度试件计算结果 Calculated results of specimens with different thickness vertical ribs 121

9 CF - Ⅱ CF - Ⅰ T J DU Guofeng XU Lihua XU Haoran et al. Study on composite T - shaped concrete filled steel tubular columns under eccentric compression J. Journal of Building Structures in Chinese 2. T J ZUO Zhiliang CAI Jian LIU Mingfeng et al. Experimental study of T - shaped CFT stub columns with binding bars subjected to eccentric load J. Journal of Building Structures in Chinese 3. L J CAI Jian ZUO Zhiliang ZHAO Xiaoqin et al. Experimental research on eccentrically loaded L - shaped CFT stub columns with binding bars J. Journal of Building Structures in Chinese 4. J LI Zhenyu CHEN Zhihua RONG Bin et al. Construction in Chinese Research on crisscross combined column of concrete filled square tubes J. Industrial 5. J CAO Wanlin FAN Tai ZHANG Weibin et al. Test and analysis of the seismic performance of SRC columns of irregular sections J. China civil engineering journal in Chinese 6. L J CHEN Zhihua RONG Bin. Research on axial compression stability of L - shaped column composed of concrete - filled square steel tubes J. Building Structure in Chinese 7. - J HE Yibin XIAO Alin GUO Jian et al. Bearing capacity of stub columns composed of structure steel and self - compacting high - strength concrete - filled steel tube experimental reseach J. Journal of natural disasters in Chinese 8. J CAO Wanlin WANG Zhihui PENG Bin et al. Experimental study on axial compression performance of multi - cell CFST mega - columns with steel reinforcement cage inside J. Structural Engineers in Chinese 9. M HAN Linhai. Concrete - filled Steel Tube Structures theory and Practice M. 2nd ed. Beijing Science Press in Chinese J GUO Zhenhai ZHANG Xiuqin. Stress - strain curve of concrete subjected to cyclic loadings J. Metallurgy Architecture in Chinese