摘要
提出了一种新型高延性纤维混凝土(HDFRC)-钢管-混凝土(HDCSTC)叠合柱,研究了螺杆列数、螺杆强度和螺母类型对HDCSTC叠合柱轴压性能的影响.结果表明:增加螺杆列数能够有效改善试件的峰值后延性;螺杆强度增加,对1列螺杆试件的延性无显著影响,对2列螺杆试件的延性影响较大;吊环螺母能够与外侧高延性纤维混凝土建立有效拉结,改善试件的峰值后性能;HDCSTC叠合柱具有与钢筋混凝土柱同等优异的轴压性能,且施工方便无技术限制,值得推广使用.
关键词
近年来中国倡导大力发展装配式建

图1 HDCSTC 叠合柱构造
Fig.1 HDCSTC composite column structure
已有钢筋混凝土叠合柱的研
钢管混凝土叠合柱在解决了钢管混凝土柱耐火性差和耐久性差的同时,还具有优异的受压性能和抗震性
相比钢筋混凝土叠合柱,HDCSTC叠合柱的钢管可作为外侧HDFRC浇筑的内侧模板,预制构件制作工艺简单.相比于钢管混凝土叠合柱,HDCSTC叠合柱可实现装配式,省去了现场绑扎钢筋的麻烦.本文对7个HDCSTC叠合柱试件和1个钢筋混凝土柱开展了轴压试验,主要研究了螺杆列数(nb)、螺杆强度(fyb)和螺母类型(包括吊环螺母(R)和普通螺母(N))等参数对HDCSTC叠合柱轴压受力性能的影响.
为研究HDCSTC叠合柱在轴压作用下的受力性能,共开展了包括7个HDCSTC叠合柱(CC系列)和1个钢筋混凝土柱(RC系列)的轴压试验,试件构造如

图2 试件构造
Fig.2 Details of specimens(size: mm)
Specimen No. | nb | fyb/MPa | Nut type | Screw type | l/mm | /% |
---|---|---|---|---|---|---|
CC‑0 | 0 | 2.38 | ||||
CC‑RNS1 | 1 | 450 | R | NS | 110 | 2.41 |
CC‑RNS2 | 2 | 450 | R | NS | 75 | 2.47 |
CC‑NNS1 | 1 | 450 | N | NS | 110 | 2.41 |
CC‑NNS2 | 2 | 450 | N | NS | 75 | 2.47 |
CC‑RHS1 | 1 | 752 | R | HS | 110 | 2.41 |
CC‑RHS2 | 2 | 752 | R | HS | 75 | 2.47 |
RC‑50 | 50 | 5.07 |
HDCSTC叠合柱试件加载前,测得其标准棱柱体轴心抗压强度fc为63.7 MPa.HDFRC的配合比如
Water | Cement | Fly ash | Silica flour | Quartz sand | Superplasticizer | Steel fiber | PE fiber |
---|---|---|---|---|---|---|---|
285.000 | 285.000 | 741.000 | 114.000 | 608.300 | 3.648 | 157.000 | 9.700 |
Fiber type | Length/mm | Diameter/mm | Density/ (kg · | Tensile strength/GPa | Elastic modulus/GPa |
---|---|---|---|---|---|
PE fiber | 18 | 0.017-0.019 | 970 | 2 900 | 114 |
Steel fiber | 13 | 0.220 | 7 850 | 2 000 |

图3 HDFRC受拉应力-应变曲线和破坏形态
Fig.3 Stress‑strain curves and final failure modes of HDFRC under tensile load

图4 HDFRC受压应力-应变曲线及破坏形态
Fig.4 Stress‑strain curves and final failure modes of HDFRC under compression load

图5 钢材的应力-应变曲线
Fig.5 Stress‑strain curves of the steel
Steel type | Elastic modulus/GPa | Yield strength/MPa | Tensile strength/MPa | Elongation/% |
---|---|---|---|---|
2.8 mm steel plate | 208 | 309 | 478 | 35.3 |
8 steel bar | 194 | 439 | 602 | 25.8 |
16 steel bar | 192 | 418 | 593 | 36.2 |
Normal screw | 131 | 446 | 450 | 29.1 |
High strength screw | 115 | 580 | 752 | 33.0 |
试件的测点布置如

图6 加载装置和测点布置
Fig.6 Loading device and layout of monitoring points(size:mm)

图7 试件的轴向荷载-应变曲线
Fig.7 Axial load‑strain curves of specimens
Specimen No. | Nm/kN | εm/% | εc/% | εe/% | εb/% | N0/kN | SI | Ι5 | Ι10 |
---|---|---|---|---|---|---|---|---|---|
CC‑0 | 6 023.6 | 0.32 | 0.32 | 3.11 | 6 008.0 | 1.00 | 3.72 | 5.81 | |
CC‑RNS1 | 5 902.8 | 0.30 | 0.33 | 2.38 | 2.02 | 6 008.0 | 0.98 | 4.35 | 7.24 |
CC‑RHS1 | 6 485.7 | 0.38 | 0.31 | 3.27 | 2.40 | 6 008.0 | 1.08 | 4.18 | 6.55 |
CC‑RNS2 | 5 876.9 | 0.33 | 0.47 | 2.67 | 2.91 | 6 008.0 | 0.98 | 4.56 | 7.94 |
CC‑RHS2 | 6 266.2 | 0.42 | 0.50 | 3.62 | 6 008.0 | 1.04 | 4.77 | 8.95 | |
CC‑NNS1 | 5 669.5 | 0.33 | 0.38 | 1.71 | 3.26 | 6 008.0 | 0.94 | 4.05 | 6.29 |
CC‑NNS2 | 5 813.7 | 0.39 | 0.25 | 1.80 | 1.85 | 6 008.0 | 0.97 | 4.24 | 6.92 |
RC‑50 | 7 025.8 | 0.39 | 0.40 | 4.49 | 8.37 |
Note: εm is the average axial strain corresponding to the peak axial load;εc is the average axial strain corresponding to the initial crushing of concrete;εe is the average axial strain corresponding to the HDFRC layer is peeled off;εb is the average axial strain corresponding to the bolt is broken.

图8 试件的最终破坏形态
Fig.8 Final failure modes of specimens
为评价HDFRC层、钢管和核心区混凝土之间的相互作用,将试件的峰值轴向荷载Nm和名义轴向荷载N0之间的比值定义为强度指标SI.此外,考虑到混凝土尺寸效应的影响,在计算核心混凝土和HDFRC层对试件峰值轴向荷载的贡献时,参考BS EN 1994‑1‑1:2004 Eurocode:Design of Composite Steel and Concrete Structure Part 1‑1:Gerneral Rules and Rules for Buildings,取0.85的强度折减系数,具体计算式如下:
(1) |
(2) |
式中:fc、fHC分别为核心区混凝土和HDFRC的轴心抗压强度,fy为钢管的屈服强度;Ac、As、AHC分别为核心区混凝土、钢管和HDFRC层的横截面积.
构件的延性通常指构件达到峰值承载力后的变形能力,1997年Foster
规范GB 50936—2014《钢管混凝土结构技术规范》取钢管和混凝土的轴压刚度之和作为钢管混凝土柱的组合轴向刚度,依据叠加原理,取钢管、内填混凝土和HDFRC三部分的轴压刚度之和,作为HDCSTC叠合柱的组合轴压刚度(K),其计算式如下:
(3) |
式中:Ec、Es、EHC分别为核心混凝土、钢管和HDFRC的弹性模量.
试验测得混凝土的立方体抗压强度为70.4 MPa,根据GB/T 50010-2010《混凝土结构设计规范》,C60混凝土的Ec值为3.6×1
Specimen No. | Ec/ (N·m | Es/ (N·m | EHC/(N·m | Nm/kN | N30%/kN | εav/% | Kt×1 | Kc×1 | Kt/Kc |
---|---|---|---|---|---|---|---|---|---|
CC‑0 | 36 000 | 208 000 | 18 160 | 6 023.6 | 1 807.1 | 0.067 | 2.69 | 3.10 | 0.87 |
CC‑RNS1 | 36 000 | 208 000 | 18 160 | 5 902.8 | 1 770.8 | 0.067 | 2.65 | 3.10 | 0.85 |
CC‑RHS1 | 36 000 | 208 000 | 18 160 | 6 485.7 | 1 945.7 | 0.073 | 2.68 | 3.10 | 0.86 |
CC‑RNS2 | 36 000 | 208 000 | 18 160 | 5 876.9 | 1 763.0 | 0.069 | 2.55 | 3.10 | 0.82 |
CC‑RHS2 | 36 000 | 208 000 | 18 160 | 6 266.2 | 1 880.0 | 0.064 | 2.92 | 3.10 | 0.94 |
CC‑NNS1 | 36 000 | 208 000 | 18 160 | 5 669.5 | 1 700.9 | 0.062 | 2.73 | 3.10 | 0.88 |
CC‑NNS2 | 36 000 | 208 000 | 18 160 | 5 813.7 | 1 744.1 | 0.061 | 2.87 | 3.10 | 0.93 |
由
螺杆列数(nb)对试件的轴向荷载-应变曲线的影响如

图9 螺杆列数对轴向荷载-应变曲线的影响
Fig.9 Influence of the number of screw rows on axial load‑strain curve
螺杆强度对试件轴向荷载-应变曲线的影响如

图10 螺杆强度对试件轴向荷载-应变曲线的影响
Fig.10 Influence of screw strength on axial load‑strain curve of specimens

图11 钢管截面的侧向受力图
Fig.11 Lateral stress diagram of steel tube section

图12 核心混凝土有效约束区
Fig.12 Core concrete effective confinement zone
螺母类型对试件轴向荷载-应变曲线的影响如

图13 螺母类型对试件轴向荷载-应变曲线的影响
Fig.13 Influence of nut type on axial load‑strain curves of specimens
在CC系列试件中,试件CC‑RHS2的性能最为优越.对普通钢筋混凝土柱而言,试件RC‑50的体积配箍率处于较高的水平,同时HDCSTC叠合柱试件中钢管截面积为2 432.6 m

图14 试件RC‑50和CC‑RHS2的N‑ε 对比曲线
Fig.14 Comparison of N‑ε curves for specimen RC‑50 and CC‑RHS2
从施工成本考虑,与钢筋混凝土叠合柱相比,HDCSTC叠合柱的预制构件制作时无需架设内侧模板,且无技术门槛,更不需要采用离心法等特殊技术.同时,由于HDFRC的使用,钢管外侧无需绑扎钢筋,使HDCSTC叠合柱的施工成本与传统叠合柱相比并不会有太大差异.HDCSTC叠合柱拥有与钢筋混凝土柱同等优异的轴压性能,且施工方便无技术限制,值得推广使用.
(1)对于HDCSTC叠合柱,由于HDFRC层开裂、钢管屈服和核心混凝土被压溃,试件承受的轴向荷载在达到峰值荷载后即开始下降,且随着应变增大,其下降速率逐步减小;当应变超过2.5%后,大部分试件承受的轴向荷载基本保持恒定,残余承载力主要由核心钢管混凝土承担.
(2)HDFRC层在破坏时多发生斜向或竖向劈裂破坏,裂缝发展规律符合混凝土轴压破坏的特征,且HDFRC层受损最严重的区域与钢管屈曲的位置基本重合.
(3)对于HDCSTC叠合柱,螺杆列数增加能有效改善试件的延性.螺杆强度增加,对1列螺杆试件的延性无显著影响,对2列螺杆试件的极限承载力和延性影响较大.与采用普通螺母的试件相比,采用吊环螺母的试件裂缝数量更多、更密集.使用吊环螺母可有效减缓HDCSTC叠合柱的承载力退化,改善试件的延性.
(4)HDCSTC叠合柱拥有与钢筋混凝土柱同等优异的轴压性能,且施工方便无技术限制,值得推广使用.
参考文献
陈骏, 彭畅, 李超, 等.装配式建筑发展概况及评价标准综述[J].建筑结构, 2022, 52(增刊2): 1503‑1508. [百度学术]
CHEN Jun, PENG Chang, LI Chao, et al. A review of development situation and assessment standard for prefabricated buildings[J]. Building Structure, 2022, 52(Suppl 2): 1503‑1508.(in Chinese) [百度学术]
张锡治, 章少华, 牛四欣. 装配式建筑中预制混凝土管柱的研究与展望[J]. 建筑结构, 2018, 48(7):79‑86. [百度学术]
ZHANG Xizhi, ZHANG Shaohua, NIU Sixin. Research and prospect of precast concrete tubular column in prefabricated buildings[J]. Building Structure, 2018, 48(7):79‑86. (in Chinese) [百度学术]
郭纯, 凌国飞. 一种新型预制管混凝土柱的轴压性能研究[J]. 工业建筑, 2008, 38(1):88‑91. [百度学术]
GUO Chun, LING Guofei. Experiment on a new axially loaded column of concrete filled prefabricated tubular members[J]. Industrial Construction, 2008, 38(1):88‑91. (in Chinese) [百度学术]
KIM C S, LIM W Y, PARK H G, et al. Cyclic loading test for cast‑in‑place concrete‑filled hollow precast concrete columns[J]. ACI Structural Journal, 2016, 113(2):205‑215. [百度学术]
KIM C S, LEE H J, PARK C K, et al. Cyclic loading test for concrete‑filled hollow precast concrete columns produced by using a new fabrication method[J]. Journal of Structural Engineering, 2017, 143(4):04016212. [百度学术]
徐梁晋, 王义博, 张志刚, 等. 预制ECC管混凝土桥墩拟静力试验研究[J]. 工程力学, 2021, 38(5):229‑238. [百度学术]
XU Liangjin, WANG Yibo, ZHANG Zhigang, et al. Quasi‑static test study on precast ECC concrete‑filled tubular bridge piers[J]. Engineering Mechanics, 2021, 38(5):229‑238. (in Chinese) [百度学术]
张斌, 胡红松, 杨朱金. 方钢管超高强钢纤维混凝土柱轴压性能研究[J]. 建筑材料学报, 2023, 26(5):547‑554. [百度学术]
ZHANG Bin, HU Hongsong, YANG Zhujin. Axial compressive behavior of ultra‑high‑strength steel fiber‑reinforced concrete‑filled square steel columns[J]. Journal of Building Materials, 2023, 26(5):547‑554. (in Chinese) [百度学术]
PARK H G, LEE H J, CHOI I R, et al. Concrete‑filled steel tube columns encased with thin precast concrete[J]. Journal of Structural Engineering, 2015, 141(12):04015056. [百度学术]
HAN L H, AN Y F. Performance of concrete‑encased CFST stub columns under axial compression[J]. Journal of Constructional Steel Research, 2014, 93:62‑76. [百度学术]
JI X D, KANG H D, CHEN X C, et al. Seismic behavior and strength capacity of steel tube‑reinforced concrete composite columns[J]. Earthquake Engineering and Structural Dynamics, 2014, 43(4):487‑505. [百度学术]
CAI J M, PAN J L, LI X P. Behavior of ECC‑encased CFST columns under axial compression[J]. Engineering Structures, 2018, 171:1‑9. [百度学术]
WU Q X, SHE Z M, YUAN H H. Experimental study of UHPC‑encased CFST stub columns under axial compression[J]. Structures, 2021, 32:433‑447. [百度学术]
王龙, 池寅, 徐礼华, 等. 混杂纤维超高性能混凝土力学性能尺寸效应[J]. 建筑材料学报, 2022, 25(8):782‑789. [百度学术]
WANG Long, CHI Yin, XU Lihua, et al. Size effect of mechanical properties of hybrid fiber ultra‑high performance concrete[J]. Journal of Building Materials, 2022, 25(8):782‑789. (in Chinese) [百度学术]
王振波, 左建平, 张君, 等. 混杂纤维延性水泥基材料单轴受压力学特性[J]. 建筑材料学报, 2018, 21(4):639‑644. [百度学术]
WANG Zhenbo, ZUO Jianping, ZHANG Jun, et al. Mechanical properties of hybrid fiber reinforced engineered cementitious composites under uniaxial compression[J]. Journal of Building Materials, 2018, 21(4):639‑644. (in Chinese) [百度学术]
杨曌, 钟奕岚, 杨智, 等. SMA/PVA混杂纤维增强水泥基复合材料拉伸性能[J]. 建筑材料学报, 2023, 26(5):555‑562. [百度学术]
YANG Zhao, ZHONG Yilan, YANG Zhi, et al. Tensile properties of SMA/PVA hybrid fiber reinforced cementitious composites[J]. Journal of Building Materials, 2023, 26(5):555‑562. (in Chinese) [百度学术]
崔凯, 徐礼华, 池寅. 钢-聚丙烯混杂纤维混凝土等幅受压疲劳变形[J]. 建筑材料学报, 2023, 26(7):755‑761. [百度学术]
CUI Kai, XU Lihua, CHI Yin. Fatigue deformation of steel‑polypropylene hybrid fiber reinforced concrete under constant‑amplitude cyclic compression[J]. Journal of Building Materials, 2023, 26(7):755‑761. (in Chinese) [百度学术]
FOSTER S J, ATTARD M M. Experimental tests on eccentrically loaded high strength concrete columns[J]. Structural Journal, 1997, 94(3):295‑303. [百度学术]