Experimental Study on Seismic Performance of RC Columns Made of Ultra-High-Strength Materials
-
摘要: 最近发生的强震表明,传统的延性结构在超过设计水准强震作用下会产生过大的残余变形而导致结构难以修复. 为保证结构在大变形阶段具有正刚性和较小残余变形,采用低黏结高强度的钢绞线用来代替混凝土柱中的纵向普通钢筋. 为了验证方法的有效性,以钢绞线的布置数量和混凝土的约束方式作为试验变量,对5根缩尺比例为1/3、横截面为250 mm × 250 mm、净高为1 000 mm、剪跨比为2.0和轴压比为0.25的高强混凝土方柱进行拟静力试验. 试验结果表明:低黏高强的钢绞线作为柱纵筋可使混凝土柱的水平承载力在层间位移角达3.5%之前持续保持上升趋势,同时可以有效减少柱的残余变形,并使残余层间位移角控制在相应峰值层间位移角的1/5以下;碳纤维布外包混凝土柱可防止保护层混凝土剥落,进一步减小柱在经历大变形后的残余变形.Abstract: As recent strong earthquakes have revealed, the excessive deformation of the traditional ductile structures under mega-earthquakes far more than design intensity makes the structures hard to be repaired after earthquakes. To assure sufficient resilience of concrete columns, i.e., stable response and small residual deformation under mega-earthquakes, low-bond and ultra-high-strength (UHS) prestressed concrete (PC) strands rather than deformed reinforcing barsare adopted as the longitudinal reinforcing bars. To verify this method, pseudo-static tests were conducted for five 1/3-scale concrete columns with asquare section of 250 mm × 250 mm, height of 1 000 mm, shear span ratio of 2.0, and axial load ratio of 0.25. The steel amount of UHS PC strand and confinement configuration of transverse reinforcement were experimental variables. Test results indicate that when low-bond and UHS PC strands was used aslongitudinal reinforcement, the lateral resistance of concrete columnskept increasing trend before the drift level reached 3.5%, which effectively reduced residual deformation and limited residual drift below one-fifth of the corresponding peak drift. It is also indicated that carbon fiber reinforced polymer wrapping prevents stripping of concrete cover and further reduces the residual deformation after large deformation of concrete columns.
-
Key words:
- ultra-high-strength steel strand /
- concrete /
- column /
- resilience /
- residual drift
-
表 1 试件参数和变量
Table 1. Parameters and variables of test specimens
试件 纵筋类型(和根数) ρ/% 箍筋类型 箍筋约束方式 ρν/% λ n Vu/kN Vu*/Vu εs/% εs*/εs 1# HRB400(12) 2.10 HRB335 普通箍筋,$ \phi $6@30 2.20 2 0.25 295.8 1.08 0.22 1.16 2# UHS(4),HRB400(8) 2.05 HRB335 普通箍筋,$ \phi $6@30 2.20 2 0.25 308.8 1.02 0.31 1.21 3# UHS(8),HRB400(4) 2.00 HRB335 普通箍筋,$ \phi $6@30 2.20 2 0.25 313.4 1.01 0.30 0.95 4# UHS(8),HRB400(4) 2.00 HRB335 复合箍筋,$ \phi $6@45 2.90 2 0.25 313.4 1.04 0.30 1.32 5# UHS(8),HRB400(4) 2.00 HRB335 普通箍筋,$ \phi $6@30,CFRP 2.20 2 0.25 333.2 1.06 0.37 1.32 表 2 混凝土物理力学性质指标
Table 2. Physical and mechanical properties of concrete
fcu,k/
(N•mm–2)fck/
(N•mm–2)Ec/
(N•mm–2)ν/% ρS/
(kg•m–3)εP/
( × 10–6)96.8 80.3 4.09 × 104 21.9 2 406 2 4211 表 3 钢筋物理力学指标
Table 3. Physical and mechanical properties of the used steels
钢筋 d/
mmfyk/
(N•mm–2)εs/
%ftk/
(N•mm–2)Es/
(N•mm–2)ξt/
%UHS 12.80 1 760 0.96 1 910 199 610 4.8 HRB400 11.80 418 0.21 592 204 592 14.0 HRB335 6.30 316 0.16 501 206 474 11.0 -
PRIESTLEY M J N, TAO J R. Seismic response of precast prestressed concrete frames with partially debonded tendons[J]. Precast/Prestressed Concrete Institute Journal, 1993, 38(1): 58-69. PRIESTLEY M J N, MACRAE G A. Seismic tests of precast beam-to-column joint subassemblages with unbonded tendons[J]. Precast/Prestressed Concrete Institute Journal, 1996, 41(1): 64-81. ZATAR W A, MUTSUYOSHI H. Residual displacements of concrete bridge piers subjected to near field earthquakes[J]. ACI Structural Journal, 2002, 99(6): 740-749. 汪训流. 配置高强钢绞线无粘结筋混凝土柱复位性能的研究[D]. 北京: 清华大学, 2007. 高婧,葛继平,林铁良. 干接缝节段拼装桥墩拟静力试验研究[J]. 振动与冲击,2011,30(4): 211-216. doi: 10.3969/j.issn.1000-3835.2011.04.043GAO Jing, GE Jiping, LIN Tieliang. Pseudo static test for pre-cast segmental bridge columns with dry joints[J]. Journal of Vibration and Shock, 2011, 30(4): 211-216. doi: 10.3969/j.issn.1000-3835.2011.04.043 郭佳, 辛克贵, 何铭华, 等. 自复位桥梁墩柱结构抗震性能试验研究与分析[J]. 工程力学, 2012, 29(增刊1): 29-35.GUO Jia, XIN Kegui, HE Minghua, et al. Experimental study and analysis on the seismic performance of a self-centering bridge pier[J]. Engineering Mechanics, 2012, 29(S1): 29-35. SONG L L, GU O T, GU Y, et al. Experimental study of a self-centering prestressed concrete frame subassembly[J]. Engineering Structures, 2015, 88: 176-188. doi: 10.1016/j.engstruct.2015.01.040 CUI Y, LU X L, JIANG C. Experimental investigation of tri-axial self-centering reinforced concrete frame structures through shaking table tests[J]. Engineering Structures, 2017, 132: 684-694. doi: 10.1016/j.engstruct.2016.11.066 WHITE S, PALERMO A. Quasi-static testing of posttensioned nonemulative column-footing connections for bridge piers[J]. Journal of Bridge Engineering, 2016, 21(6): 04016025-1. doi: 10.1061/(ASCE)BE.1943-5592.0000872 SHIM C, KOEM C, SONGH H, et al. Seismic performance of repaired severely damaged precast columns with high-fiber reinforced cementitious composites[J]. KSCE Journal of Civil Engineering, 2018, 22(2): 736-746. doi: 10.1007/s12205-017-1414-z SUN Y P, TAKEUCHI T, FUNATO Y, et al. Earthquake-resisting properties and evaluation of high performance concrete columns with low residual deformation[C]//Proceedings of the 15th WCEE. [S.l.]: IAEE, 2012: 0282. 孙玉平,赵世春,赵华. 节能型高恢复性钢筋混凝土柱的抗震性能与评估方法[J]. 土木工程学报,2013,46(5): 105-110.SUN Yuping, ZHAO Shichun, ZHAO Hua. Seismic behavior and evaluation of sustainable and resilient concrete columns[J]. China Civil Engineering Journal, 2013, 46(5): 105-110. 张鑫,韦合,叶列平. 高强钢筋配筋混凝土框架结构抗震性能的试验研究[J]. 土木工程学报,2009,42(5): 74-78.ZHANG Xin, WEI He, YE Lieping. Experimental study on seismic performance of RC framesreinforced with high-strength steel[J]. China Civil Engineering Journal, 2009, 42(5): 74-78. 中华人民共和国住房和城乡建设部. JGJ/T 101—2015建筑抗震试验规程(备案号J 1988—2015)[S]. 北京: 中国建筑工业出版社, 2015. FEMA. Seismic performance assessment of buildings[S]. Federal Emergency Management Agency (FEMA), Washington District of Columbia: 2-12-2-13, 2012. 徐有邻. 各类钢筋粘结锚固性能的分析比较[J]. 福州大学学报(自然科学版), 1996(增刊1): 69-75. 中华人民共和国住房和城乡建设部. GB 50010—2010混凝土结构设计规范[S]. 北京: 中国建筑工业出版社, 2010.