高层建筑钢筋混凝土框架—核心筒结构楼层层高变化对结构抗震性能的影响研究
|
摘要
近二十年来,我国已经成为世界上兴建高层建筑的主要区域。伴随着数量的快速增长,高层建筑的体型与建筑功能也日趋复杂和多样化,即使在同一座高层建筑中,楼层高度沿建筑高度方向也因建筑功能布置的要求而多有变化,高层建筑结构因局部楼层层高突变造成的结构侧向刚度不规则现象也较为普遍和突出。
本文研究围绕我国高层建筑应用最为普遍的结构形式—框架-核心筒结构,针对局部楼层层高变化对其抗震性能的影响展开,重点就框架-核心筒结构侧向刚度规则性控制方法及其控制指标、层高变化对结构变形形态、受力模式以及强烈地震作用下的屈服机制与破坏模式的影响等问题进行研究与探讨。主要研究工作及成果如下：
1)局部楼层层高的明显增大会减弱相应楼层以及整体结构的刚度,引起结构局部楼层受力与变形的放大与集中,改变构件的受力模式、屈服机制乃至破坏模式,对结构抗震不利。
数值分析以及大比例振动台试验研究均表明：局部楼层层高越大、突变越严重,其造成相应楼层位移、层间位移角、楼层剪力及倾覆力矩的放大、集中及突变现象越显著,而且随着地震动强度的增大,上述放大与集中现象均呈非线性关系增大,对结构抗震不利。此外,局部楼层层高的增大会减小楼层框架部分的抗侧刚度及其与核心筒抗侧刚度的相对比例,降低框架地震作用分担比例和构件的承载力能力冗余程度,造成构件屈服机制乃至破坏模式的转变。
2)控制结构侧向刚度的规则性是保障结构抗震安全性的关键措施之一。基于本文的研究,对于框架-核心筒结构建议采用楼层剪力与层间位移角比方法来衡量结构侧向刚度的规则性,给出不同部位的限值指标为：底层不宜小于1.5、不应小于1.4；其他楼层不宜小于0.9,当本层层高大于相邻上层层高的1.5倍时,不宜小于1.1。
3)当采用相邻楼层剪力与层间位移角比方法及本文上述建议限值进行结构侧向刚度规则性判定时,对于不满足规则性要求的楼层应采用1.25的系数放大其地震作用以提高其承载能力；当放大地震作用不能实现构件配筋及承载力的有效提高时,应直接就其构件配筋进行适当放大。
4)计算分析及振动台试验均表明：高层建筑钢筋混凝土框架-核心筒结构在强烈地震作用下,结构底部尤其是核心筒受拉效应显著。底层层高的加大会造成上述受拉效应的进一步加剧,底层核心筒墙体更趋于发生拉弯的破坏模式,应引起设计的重视。
5)本文提出的构件正截面承载力冗余系数分析方法给出了结构楼层刚度、构件受力及构件屈服机制(破坏模式)三者之间内在联系的显式表达,揭示了框架-核心筒结构局部楼层层高增大对构件屈服机制、破坏模式以及整体结构抗震性能影响的实质。
6)时程分析表明,结构上部楼层层高增大时会使得结构高振型(或顶部鞭梢效应)的影响增大,地震作用下层高变化楼层的剪力、倾覆力矩以及层间位移角均较反应谱分析大,因此仅采用反应谱分析存在不足,应补充进行弹性时程分析。
Over the past twenty years, China has become the main areas of the construction of high-rise buildings in the world. Accompanied by the rapid growth of the number, the somatotype and function of high-rise buildings are getting more complex and more diverse. Even in a same high-rise building, floor height along the building height direction would change due to the requirements of the functional layout of buildings. The lateral stiffness of irregular phenomena caused by local floor height mutation becomes very common and prominent for high-rise building structure.
In this dissertation herein, the study was carried out by focusing on the effects of local story height variations towards the frame-core wall structure, one of the most popular structural systems for high rise buildings in China. The measurement method and control indicators of lateral stiffness regularity for frame-core wall structure, the impacts of story height variation towards structural deformation morphology, force patterns, yielding mechanism and failure mode under intensive earthquake acting were emphasized to investigate and discuss. The main research work and creative results were as follows:
1) The increasing of local story height will decrease the lateral stiffness of the corresponding story and whole structure, lead to forces and deformations amplified and concentrated at individual story, change the stress pattern, yielding mechanism and failure mode of structural members and harm structure aseismic performance in consequence.
The results of numerical analysises and large scale shaking table tests research show that:the higher magnitudes and the more sudden changes in story height would cause greater amplification and heavier concentration of story displacement, inter-story drift angle, shear force and overturning moment at the corresponding story. And such amplification and concentration will increase in nonlinear relationship as the ground motion increasing. Moreover, the story height increase would reduce frame's the lateral stiffness and the its relative ratio to core wall's, decease the seismic action undertaking proportion of frame, the bearing capacity redundancy even the yielding mechanism and failure mode of structural members.
2) The rule of control the lateral stiffness regularity of structure is one of the key measurements to guarantee the seismic safety of structure. Base on the study of this thesis, the author recommended adopting the relative ratio of story shear to inter-story drift angle to adjacent story as the measurement method for evaluating the regularity of story lateral stiffness for frame-core wall structure. The author also proposed the story stiffness ratio limitation indicators for different locations of story, the first story should not be less than1.5and shall not be less than1.4; the other stories should not be less than1.1, should not be less than0.9when the story height is over1.5times larger than the below's.
3) When adopting the recommended method and proposed limitation value for evaluating the regularity of story lateral stiffness for frame-core wall structures, the seismic forces of structural members should be enlarged with no less1.25to improve their bearing capacities. The reinforcements should be enlarged directly when amplifying seismic forces cannot increase the reinforcements effectively.
4) The results of numerical analysis and shaking table test showed the tension effect in structure bottom; especially the core wall is heavily for high rise frame-core wall structure under intensive earthquake acting. The increase of story height would aggravate such situation. The core wall would tend to be tension-flexural failure mode. The structure designer should pay more attentions on keeping the continuity of the member and the reinforcement and the validity of anchorages.
5) The member bearing capacity redundancy method proposed in this dissertation gives the explicit expression of the internal connections between the story lateral stiffness, the member force and the yielding mechanism (failure mode) and reveals the essential characteristics of the effects of local story height increase towards the yielding mechanism, failure mode of structure members and the overall structure aseismic performance.
6) The time history dynamic analysis shows that the increases of upper story's height will increase the high mode effects and the story shear force, overturning moment and inter-story drift angle would be larger than those of response spectrum analysis. Additional time history analysis should be taken for cover the deficiency of response spectrum analysis.
本文研究围绕我国高层建筑应用最为普遍的结构形式—框架-核心筒结构,针对局部楼层层高变化对其抗震性能的影响展开,重点就框架-核心筒结构侧向刚度规则性控制方法及其控制指标、层高变化对结构变形形态、受力模式以及强烈地震作用下的屈服机制与破坏模式的影响等问题进行研究与探讨。主要研究工作及成果如下：
1)局部楼层层高的明显增大会减弱相应楼层以及整体结构的刚度,引起结构局部楼层受力与变形的放大与集中,改变构件的受力模式、屈服机制乃至破坏模式,对结构抗震不利。
数值分析以及大比例振动台试验研究均表明：局部楼层层高越大、突变越严重,其造成相应楼层位移、层间位移角、楼层剪力及倾覆力矩的放大、集中及突变现象越显著,而且随着地震动强度的增大,上述放大与集中现象均呈非线性关系增大,对结构抗震不利。此外,局部楼层层高的增大会减小楼层框架部分的抗侧刚度及其与核心筒抗侧刚度的相对比例,降低框架地震作用分担比例和构件的承载力能力冗余程度,造成构件屈服机制乃至破坏模式的转变。
2)控制结构侧向刚度的规则性是保障结构抗震安全性的关键措施之一。基于本文的研究,对于框架-核心筒结构建议采用楼层剪力与层间位移角比方法来衡量结构侧向刚度的规则性,给出不同部位的限值指标为：底层不宜小于1.5、不应小于1.4；其他楼层不宜小于0.9,当本层层高大于相邻上层层高的1.5倍时,不宜小于1.1。
3)当采用相邻楼层剪力与层间位移角比方法及本文上述建议限值进行结构侧向刚度规则性判定时,对于不满足规则性要求的楼层应采用1.25的系数放大其地震作用以提高其承载能力；当放大地震作用不能实现构件配筋及承载力的有效提高时,应直接就其构件配筋进行适当放大。
4)计算分析及振动台试验均表明：高层建筑钢筋混凝土框架-核心筒结构在强烈地震作用下,结构底部尤其是核心筒受拉效应显著。底层层高的加大会造成上述受拉效应的进一步加剧,底层核心筒墙体更趋于发生拉弯的破坏模式,应引起设计的重视。
5)本文提出的构件正截面承载力冗余系数分析方法给出了结构楼层刚度、构件受力及构件屈服机制(破坏模式)三者之间内在联系的显式表达,揭示了框架-核心筒结构局部楼层层高增大对构件屈服机制、破坏模式以及整体结构抗震性能影响的实质。
6)时程分析表明,结构上部楼层层高增大时会使得结构高振型(或顶部鞭梢效应)的影响增大,地震作用下层高变化楼层的剪力、倾覆力矩以及层间位移角均较反应谱分析大,因此仅采用反应谱分析存在不足,应补充进行弹性时程分析。
Over the past twenty years, China has become the main areas of the construction of high-rise buildings in the world. Accompanied by the rapid growth of the number, the somatotype and function of high-rise buildings are getting more complex and more diverse. Even in a same high-rise building, floor height along the building height direction would change due to the requirements of the functional layout of buildings. The lateral stiffness of irregular phenomena caused by local floor height mutation becomes very common and prominent for high-rise building structure.
In this dissertation herein, the study was carried out by focusing on the effects of local story height variations towards the frame-core wall structure, one of the most popular structural systems for high rise buildings in China. The measurement method and control indicators of lateral stiffness regularity for frame-core wall structure, the impacts of story height variation towards structural deformation morphology, force patterns, yielding mechanism and failure mode under intensive earthquake acting were emphasized to investigate and discuss. The main research work and creative results were as follows:
1) The increasing of local story height will decrease the lateral stiffness of the corresponding story and whole structure, lead to forces and deformations amplified and concentrated at individual story, change the stress pattern, yielding mechanism and failure mode of structural members and harm structure aseismic performance in consequence.
The results of numerical analysises and large scale shaking table tests research show that:the higher magnitudes and the more sudden changes in story height would cause greater amplification and heavier concentration of story displacement, inter-story drift angle, shear force and overturning moment at the corresponding story. And such amplification and concentration will increase in nonlinear relationship as the ground motion increasing. Moreover, the story height increase would reduce frame's the lateral stiffness and the its relative ratio to core wall's, decease the seismic action undertaking proportion of frame, the bearing capacity redundancy even the yielding mechanism and failure mode of structural members.
2) The rule of control the lateral stiffness regularity of structure is one of the key measurements to guarantee the seismic safety of structure. Base on the study of this thesis, the author recommended adopting the relative ratio of story shear to inter-story drift angle to adjacent story as the measurement method for evaluating the regularity of story lateral stiffness for frame-core wall structure. The author also proposed the story stiffness ratio limitation indicators for different locations of story, the first story should not be less than1.5and shall not be less than1.4; the other stories should not be less than1.1, should not be less than0.9when the story height is over1.5times larger than the below's.
3) When adopting the recommended method and proposed limitation value for evaluating the regularity of story lateral stiffness for frame-core wall structures, the seismic forces of structural members should be enlarged with no less1.25to improve their bearing capacities. The reinforcements should be enlarged directly when amplifying seismic forces cannot increase the reinforcements effectively.
4) The results of numerical analysis and shaking table test showed the tension effect in structure bottom; especially the core wall is heavily for high rise frame-core wall structure under intensive earthquake acting. The increase of story height would aggravate such situation. The core wall would tend to be tension-flexural failure mode. The structure designer should pay more attentions on keeping the continuity of the member and the reinforcement and the validity of anchorages.
5) The member bearing capacity redundancy method proposed in this dissertation gives the explicit expression of the internal connections between the story lateral stiffness, the member force and the yielding mechanism (failure mode) and reveals the essential characteristics of the effects of local story height increase towards the yielding mechanism, failure mode of structure members and the overall structure aseismic performance.
6) The time history dynamic analysis shows that the increases of upper story's height will increase the high mode effects and the story shear force, overturning moment and inter-story drift angle would be larger than those of response spectrum analysis. Additional time history analysis should be taken for cover the deficiency of response spectrum analysis.
引文
1.徐培福,傅学怡,王翠坤,肖从真.复杂高层建筑结构设计.北京：中国建筑工业出版社,2005.
2.中国建筑科学研究院结构所.高层建筑结构设计.北京：科学出版社,1985.
3. San Fernando, California, Earthquake of February 9,1971 [R], U.S. Department of Commerce, 1973.
4.徐培福,王翠坤,肖从真等.剪力墙竖向不连续结构的震害与抗震设计概念.建筑结构学报,2004年第5期
5. A. K. Chopra, V. V. Bertero, S. A. Mahin, Response of The Olive-View Medical Center Main Building During the San Fernando Earthquake, Proceeding of 5th World Conference of Earthquake Engineering, Vol. I, p.26,1973.
6.阪神淡路大震灾调查报告编辑委员会.阪神·淡路大震灾调查报告-钢筋混凝土建筑物篇.1997.7.
7.广东省地震局.1999年9月21日台湾南投7.3级地震.华南地震,第20卷,第一期,2000年3月
8.马宝民.分析汶川“5.12”震害,探求房屋“大震不倒”途径.震灾防御技术.4(1)：1-11
9. International Conference of Building Officials, Uniform Building Code,1988 Edition, Whittier,California.
10. SEAOC (1988). Recommended Lateral Force Requirements and Commentary, Structural Engineers Association of California, San Francisco, California.
11. Building Seismic Safety Council, NEHRP Recommended Provisions for Seismic Regulation of New Buildings and Other Structures. Building Seismic Safety Council, Washington, DC(2004):63-65
12.中华人民共和国国家标准.建筑抗震设计规范(GBJ 11-89)[S].北京：中国建筑工业出版社,1989
13.中华人民共和国行业标准.钢筋混凝土高层建筑结构设计与施工规程(JGJ 3-91)[S].北京：中国建筑工业出版社,1991
14.中华人民共和国国家标准.建筑抗震设计规范(GB50011-2001)[S].北京：中国建筑工业出版社,2001
15.中华人民共和国行业标准.钢筋混凝土高层建筑结构设计与施工规程(JGJ3-2002)[S]. 北京：中国建筑工业出版社,2002.
16.中华人民共和国行业标准.钢筋混凝土高层建筑结构设计与施工规程(JGJ 3-2010)[S].北京：中国建筑工业出版社,2010.
17. Ministry of Public Works and Settlement, Specification for Structures to Be Built in Disaster Areas-2007, Ankara, Turkey,2007.
18. Provisions and Commentary on Indian Seismic Code, IS 1893, Kanpur,2004.
19. Fernandez J. Earthquake response analysis of buildings considering the effects of structural configuration [R]. In Bulletin of the International Institute of Seismology and Earthquake Engineering, Tokyo, Japan,1983,19:203-215.
20. Valmundsson E V, Nau J M. Seismic response of building frames with vertical structural irregularities [J]. Journal of Structural Engineering,1997,123(1):30-41.
21. Ali A. K. Al-Ali., Helmut Krawinkler. Effects of Vertical Irregularities on Seismic Behavior of Building Structures [R]. Department of Civil and Environmental Engineering, Stanford University, Report No.130,1998.
22. Satrajit Das. Seismic Design of Vertically Irregular Reinforced Concrete Structures [D]. North Carolina State University,2000.
23.廖宇飚.高层建筑结构侧向刚度变化及其控制方法研究[硕士学位论文].中国建筑科学研究院,2005.
24.季静,韩小雷,郑宜,雷磊.高层建筑楼层侧向刚度变化控制准则的研究,结构工程师,第22卷第5期,2006年10月.
25.江韩,王珊珊,左江.高层建筑结构侧向刚度计算方法的探讨.江苏建筑2008年第1期(总第118期)
26.唐曹明.钢筋混凝土框架结构层刚度比限制方法研究[博士学位论文].中国建筑科学研究院,2009.
27.《SEAOC Seismic Design Manual》.1997.
28.中国建筑科学研究院.高层建筑结构仿真分析研究报告2：高层建筑结构抗震性能静、动力弹塑性分析仿真技术[R].北京：中国建筑科学研究院,2011
29. Chopra, A. K. Dynamics of Structures:Theory and Applications to Earthquake Engineering:3rd edition(影印版).北京：清华大学出版社,2009
2.中国建筑科学研究院结构所.高层建筑结构设计.北京：科学出版社,1985.
3. San Fernando, California, Earthquake of February 9,1971 [R], U.S. Department of Commerce, 1973.
4.徐培福,王翠坤,肖从真等.剪力墙竖向不连续结构的震害与抗震设计概念.建筑结构学报,2004年第5期
5. A. K. Chopra, V. V. Bertero, S. A. Mahin, Response of The Olive-View Medical Center Main Building During the San Fernando Earthquake, Proceeding of 5th World Conference of Earthquake Engineering, Vol. I, p.26,1973.
6.阪神淡路大震灾调查报告编辑委员会.阪神·淡路大震灾调查报告-钢筋混凝土建筑物篇.1997.7.
7.广东省地震局.1999年9月21日台湾南投7.3级地震.华南地震,第20卷,第一期,2000年3月
8.马宝民.分析汶川“5.12”震害,探求房屋“大震不倒”途径.震灾防御技术.4(1)：1-11
9. International Conference of Building Officials, Uniform Building Code,1988 Edition, Whittier,California.
10. SEAOC (1988). Recommended Lateral Force Requirements and Commentary, Structural Engineers Association of California, San Francisco, California.
11. Building Seismic Safety Council, NEHRP Recommended Provisions for Seismic Regulation of New Buildings and Other Structures. Building Seismic Safety Council, Washington, DC(2004):63-65
12.中华人民共和国国家标准.建筑抗震设计规范(GBJ 11-89)[S].北京：中国建筑工业出版社,1989
13.中华人民共和国行业标准.钢筋混凝土高层建筑结构设计与施工规程(JGJ 3-91)[S].北京：中国建筑工业出版社,1991
14.中华人民共和国国家标准.建筑抗震设计规范(GB50011-2001)[S].北京：中国建筑工业出版社,2001
15.中华人民共和国行业标准.钢筋混凝土高层建筑结构设计与施工规程(JGJ3-2002)[S]. 北京：中国建筑工业出版社,2002.
16.中华人民共和国行业标准.钢筋混凝土高层建筑结构设计与施工规程(JGJ 3-2010)[S].北京：中国建筑工业出版社,2010.
17. Ministry of Public Works and Settlement, Specification for Structures to Be Built in Disaster Areas-2007, Ankara, Turkey,2007.
18. Provisions and Commentary on Indian Seismic Code, IS 1893, Kanpur,2004.
19. Fernandez J. Earthquake response analysis of buildings considering the effects of structural configuration [R]. In Bulletin of the International Institute of Seismology and Earthquake Engineering, Tokyo, Japan,1983,19:203-215.
20. Valmundsson E V, Nau J M. Seismic response of building frames with vertical structural irregularities [J]. Journal of Structural Engineering,1997,123(1):30-41.
21. Ali A. K. Al-Ali., Helmut Krawinkler. Effects of Vertical Irregularities on Seismic Behavior of Building Structures [R]. Department of Civil and Environmental Engineering, Stanford University, Report No.130,1998.
22. Satrajit Das. Seismic Design of Vertically Irregular Reinforced Concrete Structures [D]. North Carolina State University,2000.
23.廖宇飚.高层建筑结构侧向刚度变化及其控制方法研究[硕士学位论文].中国建筑科学研究院,2005.
24.季静,韩小雷,郑宜,雷磊.高层建筑楼层侧向刚度变化控制准则的研究,结构工程师,第22卷第5期,2006年10月.
25.江韩,王珊珊,左江.高层建筑结构侧向刚度计算方法的探讨.江苏建筑2008年第1期(总第118期)
26.唐曹明.钢筋混凝土框架结构层刚度比限制方法研究[博士学位论文].中国建筑科学研究院,2009.
27.《SEAOC Seismic Design Manual》.1997.
28.中国建筑科学研究院.高层建筑结构仿真分析研究报告2：高层建筑结构抗震性能静、动力弹塑性分析仿真技术[R].北京：中国建筑科学研究院,2011
29. Chopra, A. K. Dynamics of Structures:Theory and Applications to Earthquake Engineering:3rd edition(影印版).北京：清华大学出版社,2009