考虑土-基础-结构相互作用的网架结构地震响应分析
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摘要
基于George Gazetas等提出的公式计算得出基础动力阻抗,将土对基础的动、静力作用简化为弹簧-阻尼体系作用在结构上,利用ANSYS软件建立刚性基础、独立基础和条形基础下正放四角锥网架的空间有限元整体计算模型。在此基础之上,分别研究了土-基础-结构相互作用对某24m×30m网架的静力受力特性、自振特性和地震响应特性的影响。研究结果表明,考虑土-基础-结构相互作用使结构自振频率减小,周期延长;当基础刚度满足结构受力和变形要求时,土-基础-结构相互作用对网架静力受力特性、自振特性和地震响应特性的影响可忽略不计,基于刚性基础假设的设计、计算方法是安全可靠的。
Based on George Gazetas′ formulas,the dynamic stiffness and damp of the fundation are calculated.The static and dynamic action of the soil to the foundation is simplified as a spring-dashpot system in the structural analysis.A three dimensional model for a paramid grid truss with rigid foundation,independent foundation and strip footing is established by ANSYS software.Then the effect of the soil-foundation-structure interaction on the static,the dynamic characteristics and the seismic response of a 24m×30m space grid are studied respectively.The research shows that the natural frequency will be lower and the period will be longer after the consideration of soil-foundation-structure interaction.When the stiffness of the foundation meet the requirements of the load and the deformation the effect of the soil-foundation-structure interaction on the static behavior,vibration characteristics and seismis response of the space grid can be ignored,at the same time the design and the calculation method based on the solid foundation assumption are reliable.
Based on George Gazetas′ formulas,the dynamic stiffness and damp of the fundation are calculated.The static and dynamic action of the soil to the foundation is simplified as a spring-dashpot system in the structural analysis.A three dimensional model for a paramid grid truss with rigid foundation,independent foundation and strip footing is established by ANSYS software.Then the effect of the soil-foundation-structure interaction on the static,the dynamic characteristics and the seismic response of a 24m×30m space grid are studied respectively.The research shows that the natural frequency will be lower and the period will be longer after the consideration of soil-foundation-structure interaction.When the stiffness of the foundation meet the requirements of the load and the deformation the effect of the soil-foundation-structure interaction on the static behavior,vibration characteristics and seismis response of the space grid can be ignored,at the same time the design and the calculation method based on the solid foundation assumption are reliable.
引文
[1]朱志辉.土-箱基-框架结构动力相互作用的试验研究与理论分析[D].长沙:湖南大学,2006.
[2]周文欢.考虑基础形式的土-结构共同作用钢框架抗震分析[D].上海:同济大学,2007.
[3]Penzien J,Scheffey C F.Seismic analysis of bridges onlong piles[J].ASCE,1964,90(3):223-254.
[4]王浩,杨玉冬,李爱群,等.土-桩-结构相互作用对大跨度CFST拱桥地震反应的影响[J].东南大学学报:自然科学版,2005,35(3):433-437.
[5]曹资,薛素铎,张毅刚,等.单层球面网壳在多维地震作用下的随机响应分析[J].空间结构,2002,8(2):3-11.
[6]Shiro K.Seismic design method of single layer reticulardomes with braces subjected to severe earthquakemotions[C]//The sixth pacific conference on shell andspatial structure.Seoul,Korea:Hakmun PublishingInc,2000:131-133.
[7]Gazetas G.Formulas and charts for impedances of surfaceand embedded foundations[J].Journal of GeotechnicalEngineering,1991,117(9):1363-1381.
[8]GB 50011—2001建筑抗震设计规范[S].
[2]周文欢.考虑基础形式的土-结构共同作用钢框架抗震分析[D].上海:同济大学,2007.
[3]Penzien J,Scheffey C F.Seismic analysis of bridges onlong piles[J].ASCE,1964,90(3):223-254.
[4]王浩,杨玉冬,李爱群,等.土-桩-结构相互作用对大跨度CFST拱桥地震反应的影响[J].东南大学学报:自然科学版,2005,35(3):433-437.
[5]曹资,薛素铎,张毅刚,等.单层球面网壳在多维地震作用下的随机响应分析[J].空间结构,2002,8(2):3-11.
[6]Shiro K.Seismic design method of single layer reticulardomes with braces subjected to severe earthquakemotions[C]//The sixth pacific conference on shell andspatial structure.Seoul,Korea:Hakmun PublishingInc,2000:131-133.
[7]Gazetas G.Formulas and charts for impedances of surfaceand embedded foundations[J].Journal of GeotechnicalEngineering,1991,117(9):1363-1381.
[8]GB 50011—2001建筑抗震设计规范[S].
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