Earthquake response analysis on cooling tower structure taking into account soil structure dynamic interaction
TAO Lei1, ZHANG Jun-fa2,CHEN Hou-qun3
1.Faculty of Water Resources and Hydroelectric Engineering, Xi’an University of technology, Xi’an 710048, Shaanxi, China;
2. Faculty of Civil Engineering and Architecture, Xi’an University of technology, Xi’an 710048, Shaanxi, China;
3. Earthquake Engineering Research Center, China Institute of Water Resources and Hydropower Research, Beijing, 100048, China
Large-scale high-rise reinforced concrete cooling tower belongs to typical wind-sensitive structure. In recent years, study on dynamic response under extreme external actions, such as earthquake, jet-crash, blasting et. al gets extensive concern in engineering field. Research on earthquake response influence for projects like dams, bridges and so on taking into account soil structure dynamic interaction is relatively abundant, however it is seldom involved in cooling tower. Based on elastic wave motion theory combined with finite element method, 3D viscous-spring artificial boundary model and formula were set up and deduced while considering soil structure dynamic interaction, and verify the accuracy of the earthquake input method through half space free field model. A large cooling tower in coal-fired power plant in domestic engineering project as the research background, based on general program ANSYS platform, cooling tower rigid foundation model, massless foundation model and viscoelastic artificial boundary model were modeled respectively. Modal analysis and elastic time history analysis were performed in order to study dynamic characteristics and changes of internal force, influence law of soil structure dynamic interaction for the different model was discussed. Research results show that the cooling tower structure system natural vibration frequency distribution is very dense, and the vast majority of vibration modes are local coupling vibration mode in ring and meridian directions. The natural vibration frequencies are reduced due to considering elastic foundation, and the whole vibration mode appear earlier. Through time history analysis it can be seen that by using the viscous-spring artificial boundary model, considering the infinite foundation radiation damping effect, compared with the rigid foundation model, the maximum absolute acceleration of tower reduces to 43.4%. Moment and axial force in meridian direction reduces 50%, and in ring direction increases significantly. Internal force amplitude value for X columns reduces about 20%~50%. Therefore, when performed the earthquake response analysis of cooling tower, it cannot be neglected influence of soil structure interaction.
［1］ 柯世堂,陈少林,葛耀君等.超大型冷却塔随机地震响应分析[J].地震工程与工程振动,2012,32(6):159-165.
KE Shi-tang, CHEN Shao-lin, GE Yao-jun, et al. Earthquake stochastic response analysis of super large cooling towers [J].Journal of earthquake engineering and engineering vibration, 2012, 32(6): 159-165.
［2］构筑物抗震设计规范(GB50191-2012)[S].中国计划出版社, 2012.
［3］ Gupta A K, Schnobrich W C. Seismic analysis and design of hyperbolic cooling towers [J].Nuclear Engineering and design, 1976, 36(2): 251-260.
［4］ Wolf J P. Seismic analysis of cooling towers [J].Engineering Structures, 1986, 8(3): 191-198.
［5］ Nasir AM, Thambiratnam DP, Butler D, et al. Dynamics of axisymmetric hyperbolic shell structures [J].Thin-Walled Structures, 2002, 40(7-8): 665-690.
［6］ Sabouri-Ghomi S, Nik FA, Roufegarinejad A, et al. Numerical study of the nonlinear dynamic behavior of reinforced concrete cooling towers under earthquake excitation [J].Advances in Structural Engineering, 2006, 9(3): 433-442
［7］ 叶 浩,李华峰,黄志龙.基于混凝土损伤塑性模型的自然通风冷却塔非线性抗震分析[J].电力建设,2014,35(9):88-92.
YE Hao, LI Hua-feng, HUANG Zhi-long. Nonlinear seismic response of natural draft cooling tower based on concrete damaged plasticity model [J].Electric Power Construction, 2014, 35(9): 88-92.
［8］ A.M. Horr, M. Safi. Full dynamic analysis of large concrete cooling towers: soil structure interaction [J].International journal of space structures, 2002, 17 (4): 301–312.
［9］ 高 标,卢红前.SSI效应对大型双曲线冷却塔结构抗震性能的影响[J].武汉大学学报(工学版),2009,42(Sup):427-431.
GAO Biao, LU Hong-qian. Influence of SSI effect on aseismic performance of hyperbolic cooling tower [J].Engineering Journal of Wuhan University, 2009, 42(Sup): 427-431.
［10］李 辉,张俊发.超大型冷却塔考虑土—结构相互作用的三维有限元抗震分析[J].长春工程学院学报(自然科学版), 2012,13(4):19-21.
LI Hui, ZHANG Jun-fa. The Three-dimensional finite element seismic analysis to super large cooling tower considering soil-structure interaction [J].Journal of Changchun institute technology, 2012, 13(4): 19-21.
［11］房营光.岩土介质与结构动力相互作用理论及其应用[M].北京：科学出版社，2005.
［12］薛素铎,刘 毅,李雄彦.土－结构动力相互作用研究若干问题综述[J].世界地震工程,2013,29(2):1-9.
XUE Su-duo, LIU Yi, LI Xiong-Yan. Review of some problems about research on soil-structure dynamic interaction [J].World Information on Earthquake Engineering, 2013, 29(2): 1-9.
［13］A.S.Veletsos and Y.T.Wei. Lateral and Rocking vibrations of footings [J].Journal of the soil mechanism and foundations division, ASCE, 1971, 97(1):1227-1248.
［14］J.E.Luco and R.A.Westman. Dynamic response of circular footings [J].Journal of the Engineering mechanism division, ASCE, 1971, 97(1):1381-1395.
［15］贺广零.考虑土－结构相互作用的风力发电高塔系统地震动力响应分析[J].机械工程学报,2009,45(7):87-94.
HE Guang-ling. Seismic response analysis of wind turbine tower systems considering soil-structure interaction [J].Journal of mechanical engineering,2009,45(7): 87-94.
［16］柯世堂,王同光,曹九发等.考虑土—结相互作用大型风力发电结构风致响应分析[J].土木工程学报,2015,48(2):18-25.
KE Shi-tang, WANG Tong-guang, CAO Jiu-fa, et al. Analysis on wind-induced responses of large wind power structures considering soil-structure interaction [J].China civil engineering journal, 2015, 48(2): 18-25.
［17］曹 青,张 豪.考虑土－结构相互作用的风力发电机塔架地震响应分析[J].西北地震学报,2011,33(1):62-66.
CAO Qing, ZHANG Hao. Seismic response analysis of wind turbine tower with soil-structure interaction [J].Northwestern seismological journal, 2011, 33(1): 62-66.
［18］何建涛,马怀发,张伯艳等.黏弹性人工边界地震动输入方法及实现[J].水利学报,2010,41(8):960-969.
HE Jian-tao, MA Huai-fa, ZHANG Bo-yan, et al. Method and realization of seismic motion input of viscous-spring boundary [J]. Journal of Hydraulic Engineering, 2010, 41(8): 960-969. (in Chinese)
［19］刘晶波,王振宇,杜修力等.波动问题中的三维时域粘弹性人工边界[J].工程力学,2005,22(6):46-51.
LIU Jing-bo, WANG Zhen-yu, DU Xiu-li, et al. Three-dimensional visco-elastic artificial boundaries in time domain for wave motion problems [J].Engineering Mechanics, 2005, 22(6): 46-51. (in Chinese)
［20］ Maria Radwanska，Zenon Waszczyszyn．Buckling analysis of a cooling tower shell with measured and theoretically-modeled imperfections [J].Thin-walled structures, 1995, 23(1): 107-121
