kl异形柱与短肢剪力墙结构设计中的几个问题

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1、 异形柱与短肢剪力墙结构设计中的几个问题摘要：对异形柱与短肢剪力墙结构设计中的一些问题，如计算方法、异形柱受力性能及其轴压比控制、短肢剪力墙结构中转换层的设置高度及框支柱等进行探讨，提出建议，供结构设计人员参考。 关键词：异形柱 短肢剪力墙 结构设计  现代住宅建筑要求大开间，平面及房间布置灵活、方便，室内不出现柱楞、不露梁等。异形柱与短肢剪力墙结构能较好地满足现代住宅建筑的要求，因而逐渐得到了推广应用。目前，现行国家规范或规程中尚未给出有关异形柱与短肢剪力墙结构设计的条款，因此，结构设计人员在设计中常会遇到一些规范或规程尚未论及的问题，需要设计人员积累经验，利用正确的概念进行设计。

2、本文旨在对异形柱与短肢剪力墙结构设计中的一些问题进行探讨，提出个人看法，供结构设计人员参考。 1  异形柱结构型式及其计算异形柱结构型式有异形柱框架结构、异形柱框架剪力墙结构和异形柱框架核心筒结构。异形柱结构自身的特点决定了其受力性能、抗震性能与矩形柱结构不同。由于异形柱截面不对称，在水平力作用下产生的双向偏心受压给承载力带来的影响不容忽视。因此，对异形柱结构应按空间体系考虑，宜优先采用具有异形柱单元的计算程序进行内力与位移分析。因异形柱和剪力墙受力不同，所以计算时不应将异形柱按剪力墙建模计算。当采用不具有异形柱单元的空间分析程序（如TBSA 5.0）计算异形柱结构时，可按

3、薄壁杆件模型进行内力分析。对异形柱框架结构，一般宜按刚度等效折算成普通框架进行内力与位移分析。当刚度相等时，矩形柱比异形柱的截面面积大。一般，比值（A矩A异）约在1.10-1.30之间1。因此，用矩形柱替换后计算出的轴压比数值不能直接应用于异形柱，建议用比值（A矩A异）对轴压比计算值加以放大后再用于异形柱。对有剪力墙（或核心筒）的异形柱结构，由于异形柱分担的水平剪力很小，由此产生的翘曲应力基本可以忽略，为简化计算，可按面积等效或刚度等效折算成普通框架剪力墙（或核心筒）结构进行内力与位移分析。按面积等效更能反映异形柱轴压比的情况，且面积等效计算更为简便。但应注意，按面积等效计算时，须同时满足下面

4、两式：(1)A矩=A异；(2)b/h=(Ix异Iy异)1/2式中，A矩、A异分别为矩形柱和异形柱的截面面积；b、h分别为矩形截面的宽和高；1Ix异 、Iy异分别为异形柱截面x、y向的主形心惯性矩。一般，按面积等效计算时，矩形柱的惯性矩比异形柱的小。但对有剪力墙（或核心筒）的异形柱结构，计算分析表明2，按面积等效与按刚度等效的计算结果是接近的。异形柱的截面设计，可根据上述方法得出的内力，采用适合异形柱截面受力特性的截面计算方法进行配筋计算。2  短肢剪力墙结构及其计算短肢剪力墙结构是适应建筑要求而形成的特殊的剪力墙结构。其计算模型、配筋方式和构造要求均同于普通剪力墙结构。在TAT、TB

5、SA中，只需按剪力墙输入即可，而且TAT、TBSA更适合用来计算短肢剪力墙结构。TAT、TBSA所用的计算模型都是杆件、薄壁杆件模型，其中梁、柱为普通空间杆件，每端有个自由度，墙视为薄壁杆件，每端有个自由度（多一个截面翘曲角，即扭转角沿纵轴的导数），考虑了墙单元非平面变形的影响，按矩阵位移法由单元刚度矩阵形成总刚度矩阵，引入楼板平面内刚度无限大假定减少部分未知量之后求解，它适用于各种平面布置，未知量少，精度较高。但是，薄壁杆件模型在分析剪力墙较为低宽、结构布置复杂（如有转换层）时，也存在一些不足，主要是薄壁杆件理论没有考虑剪切变形的影响，当结构布置复杂时变形不协调。而短肢剪力墙结构由于肢长较短

6、（一般为墙厚的-倍），本身较高细，更接近于杆件性能，所以，用TAT、TBSA计算短肢剪力墙结构能较好地反映结构的受力，精度较高。对设有转换层的短肢剪力墙结构，一般都只是将电梯间、楼梯间、核心筒和一少部分剪力墙落地，其于剪力墙框支。框支剪力墙是受力面向受力点过渡，由于薄壁杆件的连接处是点连接，所以用薄壁杆件模型不能很好地处理位移的连续和力的正确传递。因此，带有转换层的短肢剪力墙结构宜优先采用墙元模型软件（如SATWE）进行计算。当然，从整体上的内力（特别是下部支承柱的内力）分布情况来看，如果将剪力墙加以适当的处理，还是可以用TAT、TBSA对结构进行整体计算的3。3  异形柱的受力性能

7、及其轴压比控制天津大学的试验研究结果表明4：异形柱的延性比普通矩形柱的差。轴压比、高长比（即柱净高与截面肢长之比）是影响异形柱破坏形态及延性的两个重要因素。异形柱由于多肢的存在，其剪力中心与截面形心往往不重合，在受力状态下，各肢产生翘曲正应力和剪应力。由于剪应力，使柱肢混凝土先于普通矩形柱出现裂缝，即产生腹剪裂缝，导致异形柱脆性明显，使异形柱的变形能力比普通矩形柱降低。作为异形柱延性的保证措施，必须严格控制轴压比，同时避免高长比小于（短柱）。控制柱截面轴压比的目的，在于要求柱应具有足够大的截面尺寸，以防止出现小偏压破坏，提高柱的变形能力，满足抗震要求。广东规程按建筑抗震设计规范（GBJ1189

8、）中所规定的柱子轴压比降低0.05取用（按截面的实际面积计算）；天津规程则根据箍筋间距与主筋直径之比、箍筋直径及抗震等级共同确定，其要求比广东规程严格，例如，对s/d、（即箍筋间距s100mm，纵筋直径d分别为20mm、25mm的情况），箍筋直径dv8mm，抗震等级为三级的L形截面，其轴压比限值分别为0.60，0.65。异形柱是从短肢剪力墙向矩形柱过渡的一种构件，柱肢截面的肢厚比（即肢长肢宽）不大于。高规（JGJ391）第5.3.4条，“抗震设计时，小墙肢的截面高度不宜小于3bw”，“一、二级剪力墙的小墙肢，其轴压比不宜大于0.6”。根据上述分析，为便于应用，建议在度设防区，对于异形柱框架结构

9、，L形截面柱的轴压比不应超过0.6（按截面的实际面积计算，下同），T形截面柱的的轴压比不应超过0.65，十字形截面柱的轴压比不应超过0.8；对于异形柱框架剪力墙（或核心筒）结构，由于框架是第二道抗震防线，所以框架柱的轴压比限值可放宽到0.65（L形）、0.70（T形）、0.90（字形），但对于转换层下的支承柱，其轴压比仍不应超过0.60。短柱在压剪作用下往往发生脆性的剪切破坏，设计中应尽量避免出现短柱。根据高长比不宜小于，在梁高为600mm的前提下，当标准层层高为3.0m时，异形柱的最大肢长可为600mm；底层层高为4.2m时，肢长可为900mm。4  短肢剪力墙结构中转换层的设置高

10、度及框支柱在现代高层住宅的地下室和下部几层，由于停车和商业用房需较大空间，就得通过转换层来实现。在短肢剪力墙结构中，一般都只将电梯间、楼梯间、核心筒和一少部分剪力墙落地，其于剪力墙框支。据研究表明5，“框支剪力墙结构当转换层位置较高时，转换层附近层间位移角及内力分布急剧突变，内力的传递仅靠转换层一层楼板的间接传力途径很难实现；转换层下部的框支结构易于开裂和屈服，转换层上部几层墙体易于破坏。这种结构体系不利于抗震。高烈度区（度及度以上）不应采用；度区可以采用，但应限制转换层设置高度，可考虑不宜超过层；度区可适当放宽限制。”因此，建议在度抗震设防区，短肢剪力墙结构中转换层设置高度不宜超过层，避免高

11、位转换。转换层上下的层刚度比宜接近，不宜超过。转换层位置较高时，宜同时控制转换层下部“框支”结构的等效刚度（即考虑弯曲剪切和轴向变形的综合刚度），使EgJg与EcJc接近。EgJg为剪力墙结构的等效刚度，剪力墙结构高度取框支层的总高度，其平面和层高与转换层上部的剪力墙结构相同；EcJc为转换层下部“框支”结构的等效刚度。研究表明5，“控制转换层下部框支结构的等效刚度对于减少转换层附近的层间位移角和内力突变是十分必要的，效果也很显著。”规范对框支柱的内力、轴压比、配筋等的要求都严于普通柱。框支剪力墙结构当转换层位置较高时，如何定义框支柱，涉及到安全与经济的问题。根据圣维南原理，局部处理的影响只限

12、于局部范围，所以当转换层位置较高（如高位转换）时，除转换层附近楼层的内力较复杂外，下面的结构受到的影响很小，应与普通框架结构基本一样，不必按框支柱处理。文献计算了两个28层的结构，一为内筒外框架结构，一为内筒外框支结构，转换层设在18层。计算结果表明，转换层下二层的内力影响很大，下三层的内力误差最大为15%，下五层的内力已比较接近（最大误差小于10%）,下八层的内力已基本一样（最大误差小于5%）。这说明框支柱只需在五层范围内加以考虑，其它层的柱子按普通框架柱处理即可。因此，建议当转换层位置不超过五层时，转换层下的各层柱均按框支柱处理；当转换层位置超过五层时，转换层下相邻的五层柱按框支柱处理，而

13、其它层的柱按普通框架柱处理。由于高位转换对抗震不利，所以结构设计中应尽量避免高位转换。 5  短肢剪力墙结构的抗震薄弱环节及概念设计振动台模拟地震试验结果表明7，建筑平面外边缘及角点处的墙肢、底部外围的小墙肢、连梁等是短肢剪力墙结构的抗震薄弱环节。当有扭转效应，建筑平面外边缘及角点处的墙肢会首先开裂；在地震作用下，高层短肢剪力墙结构将以整体弯曲变形为主，底部外围的小墙肢，截面面积小且承受较大的竖向荷载，破坏严重，尤其“一”字形小墙肢破坏最严重；在短肢剪力墙结构中，由于墙肢刚度相对减小，使连梁受剪破坏的可能性增加。因此，在短肢剪力墙结构设计中，对这些薄弱环节，更应加强概念设计和抗震构造

14、措施。例如，短肢剪力墙在平面上分布要力求均匀，使其刚度中心和建筑物质心尽量接近，以减小扭转效应；适当增加建筑平面外边缘及角点处的墙肢厚度（宜取250mm，对底部外围的小墙肢根据需要可取用300mm），加强墙肢端部的暗柱配筋，严格控制墙肢截面的轴压比不超过0.6，以提高墙肢的承载力和延性；高层结构中连梁是一个耗能构件，连梁的剪切破坏会使结构的延性降低，对抗震不利，设计时应注意对连梁进行“强剪弱弯”的验算，保证连梁的受弯屈服先于剪切破坏；短肢剪力墙宜在两个方向均有梁与之拉结，连梁宜布置在各肢的平面内，避免采用“一”字形墙肢；短肢剪力墙底部加强部位的配筋应符合规范要求；等。参考文献：戴教芳多层框架异

15、形柱设计探索J.工业建筑,1996,26(1):33-35.龙卫国异形柱受力性能及结构设计有关问题探讨J四川建筑，2000,20(2):50-52.赵玉祥钢筋混凝土高层建筑设计中若干问题的探讨J建筑结构学报.1998，19(2):12-22.赵艳静等钢筋混凝土异形截面双向压弯柱延性性能的理论研究J建筑结构.1999,29(1):16-21.徐培福等转换层设置高度对框支剪力墙结构抗震性能的影响J建筑结构.2000,30(1):38-42.肖文韬等高层建筑结构计算模型的选取第五届全国高层建筑抗震技术交流会论文集S.桐庐，1995.11程绍革等高层建筑短肢剪力墙结构振动台试验研究J建筑科学.2000

16、,16(1):12-16./Porganization system and working mode, the selection of a number of municipal strengthening group to build innovation and strengthen the organization of the basic level organizations advanced model.(seven) the manual work of the Communist Youth League Organization published and League

17、branch of manual work, to promote the use of two manuals in the citys organizations at various levels. The county committee, directly under the group (work) is under the jurisdiction of grassroots League and group (total) using branch ratio shall not be less than 70%.Three, to further strengthen the

18、 groups leadership and team building(a) to strengthen the leagues leadership at all levels of construction. Continue to do a good job of municipal Party Committee Organization Department on the strengthening of the Communist Youth League cadres management opinions implementation. To promote the grou

19、p counties (autonomous counties, cities) Commission and city directly under the group (workers) appointed to carry out the Five team building activities. Improve the League Association Department working mechanism. Conscientiously fulfill the duties of CO, combined with the city group directly under

20、 (the) Committee of the general election and the adjustment, actively jointly with the unit where the party organization department good group leadership selection with the work. Do a good job in municipal Party committee assistant committee leadership and leading cadres of the annual assessment wor

21、k, adhere to and improve the assistant secretary of the Communist Youth League talk system group To weave individual conversation and collective conversation, to strengthen the committees of all levels, the Standing Committee of the Standing Committee, the establishment of a sound system of central

22、group learning, the system of investigation and study, the system of important issues and the reporting system.(two) to strengthen the work of education and training of cadres to conscientiously implement the Central Committee. On the implementation of grassroots cadres training project and opinions

23、 on carrying out the mission municipal CYL Cadres training project implementation opinions, full implementation of the project of the City Youth League cadres training education. Focus on the county grassroots cadres and workers focused on training, the new school system vocational training League c

24、adres, for the Municipal Organization Department jointly held the third session of the Communist Youth League system training cadres in party. Focusing on the construction of new socialist countryside, strengthening village cadres and rural construction team group member of the young team, the count

25、y organizations at various levels throughout the year is expected to train 100 00 rural grassroots cadres, plans to train 1000 village secretary of the village Party branch.(three) actively promote grassroots cadres election work. Under the unified leadership of the party organization, to strengthen

26、 grassroots organizations direct work, standardize the election work rules and procedures, in the designated candidate, open competition to democratically elected branch secretary at the same time, actively and steadily the development of Township, streets and other grassroots organizations in the d

27、irect election of the pilot work, on the basis of summarizing the experience and gradually expand the scope of the pilot, and gradually formed a set of measures and cadres election system.(four) to strengthen the cadres testing exercise. To study the development of XX city from 2006 to 2008 cadres t

28、esting exercise planning. To select outstanding cadres to the central mission in Beijing, Shanghai, Guangzhou and other central organs and sending work in developed areas. With the Central Committee the implementation of the western region and ethnic minorities cadres training plan . To carry out th

29、e eighth batch of municipal organs attachment cadre management, selection, training work. The outstanding cadres to start the National Development Bank XX branch testing exercise.(five) to strengthen the group construction. The main position to play the role of Youth League cadre education and train

30、ing as the city, in accordance with the requirements of post training, further curriculum scientifically and rationally, adopt arrangement menu course, basic theory includes group work, focus, hot and difficult issues, to enhance the content and practice; to strengthen the construction of teaching s

31、taff, the integration of teachers, establish a quality teacher training team, establish and implement course evaluation system; take delivery of training to the countryside, on-site training, and increase the rural grassroots cadres training efforts.Four, efforts to strengthen the work of young tale

32、nt(a) to tenth XX young 54 medal in recognition of the publicity, and actively explore the XX youth service. 54 Medal of institutionalization, standardization and socialization mechanism. Give full play to the XX award in recognition of 54 youth medal Association, Youth Award winner in the 54 chapte

33、r, investigation activities. Who won the Youth Service medal, dedication to the society to create conditions, build the stage. During the 54, named in recognition of the tenth XX young 54 medal. The association of XX editing of young talent , the exchange of information and communication platform fo

34、r the XX of outstanding young talents.(two) the establishment of municipal Party committee of young talent information database. In accordance with the feasible, effective, classification management, implement step by step principle, the establishment of municipal Party committee of youth talent dat

35、abase; guiding organizations at various levels generally established the young talent database, construction of city, county (directly under the Communist Youth League), grassroots organizations three young talent information database the relevant information collection system, and gradually establi

36、sh the citys young people, the Communist Youth League youth talent information network, provide information platform for young talent resource development.Five, take effective measures to strengthen the mission management(a) to strengthen the mission management work. Strengthen the dues collection a

37、nd management, continue to adhere to the dues collection regularly reporting system, the annual comprehensive award in recognition of the tour and the tour one vote veto system audit system. Do statistical work in the group. The group service award in recognition of the advanced units, standardizati

38、on, promoting group management work institutionalized.(two) to strengthen the organization of research and information exchange efforts. Grassroots carry out research, efforts to form a number of theoretical results. Make full use of the network carrier, to explore the establishment of electronic gr

39、oup service system, promote the work of Communist Youth League information.Attachment 4:XX municipal Party Committee Propaganda Department of the Communist Youth League work pointsIn 2006, the Communist Youth League propaganda ideological work XX to Deng Xiaoping theory and the important thought of

40、Three Represents as guidance, study and implement the partys sixteen and the spirit of the the fifth Plenary Session of the 16th CPC Central Committee implementation of the eight plenary session of the two committee, the citys cultural work conference, the Propaganda Department of the meeting and th

41、e the fourth Plenary Session of the 15th CPC Central Committee permanent mission spirit, closely around 11th Five-Year XX the goal of full implementation of Scientific Outlook on Development, emancipating the mind, seeking truth from facts, keep pace with the times, close to reality, close to life,

42、close to the young, persevere grasp orientation, grasping deepening, grasping construction innovation, further improve the groups propaganda and ideological work ability, unity To guide the majority of members of the youth to achieve the 11th Five-Year planning tasks, the overall construction of a w

43、ell-off society, building a socialist harmonious society to make new contributions.One, adhere to the Three Represents important thought and Scientific Outlook on Development education to guide the youth, to further strengthen the ideological and political education of youth(a) armed with youth scie

44、nce theory. Unremittingly with Deng Xiaoping theory and the important thought of Three Represents armed members of youth education, to promote the study and implement to expand the depth and breadth. To study and implement the important thought of Three Represents with the establishment and implemen

45、tation of Scientific Outlook on Development combine with the implementation of the requirements of constructing socialist harmonious society with Scientific Outlook on Development, carry out education as an important part of the theory of armed youth in the new period, strengthen the establishment a

46、nd implementation of Scientific Outlook on Development education, educate and guide the youth to fully understand the great significance of establishment and implementation of Scientific Outlook on Development, in-depth understanding of the Scientific Outlook on Development era back The king, the pr

47、actice foundation, basic connotation, historical status, spirit and practice requirements, a profound understanding of Scientific Outlook on Development with Marxism Leninism, Mao Zedong thought, inheriting and developing relationship between Deng Xiaoping theory and the important thought of Three R

48、epresents, to help young people establish and consciously practice Scientific Outlook on Development. Persist in learning, grasping the backbone, grasp the practice, grasp the opportunity. Catch club, effective way to grasp the network, with the group of cadres, young students and young backbone fro

49、nts as the focus, to promote the work of the armed youth theory to develop in depth, to help the youth continue to firm ideals and beliefs, to build a powerful spiritual pillar. To carry out the study and implementation of the partys sixteen session of the five Eight plenary session of the two plena

50、ry session of the Central Committee and the party spirit, to the citys Youth League members thinking into the spirit of the meeting, to achieve the goal of national consciousness and XX economic and social development in 11th Five-Year period. Contribute to help and guide the youth to a profound und

51、erstanding of the significance and main task of building a socialist harmonious society, actively join the construction of socialist harmonious society.(two) to strengthen the ideological and moral construction of teenagers. Thoroughly implement the central spirit of the document No. 8, No. 16 and t

52、he program for Improving Civic Morality to minors and students as focus groups, to strengthen and improve the ideological and moral construction of minors and the ideological and political education of college students. Make full use of the spirit and the spirit of the Three Gorges migrants Hongyan

53、XX unique the use of educational resources, school, into the team, the league, to join the party, adult occasions, extensive Hongyan spirit generation theme education activities. Use of holidays and leisure time, youth organizations three rural areas, four communities, four and moral practice, guide

54、 the youth Youth to enhance national pride, self-esteem and self-confidence, to establish the trend of the times and adapt to the trend of thinking, value orientation and behavior.(three) innovative ways and means of ideological education. Grasp the new trend of the development of the times, the new

55、 hot new features and social ideological status of young people, to further explore the methods of ideological education using modern technology and communication mode of education make lively and vivid, fully embodies the close to reality, close to life, close to the young principle through the cul

56、tivation and selection. Hongyan demonstration group, good boy, Hongyan Hongyan Youth and other forms of more scientific use of advanced typical influence and promote youth, and strive to create advocating advanced, learning advanced, striving to advance a good atmosphere.Two, in order to forge ahead

57、 with the motherland, and XX with the development as its theme, guide the youth to build a common ideological basis for the construction of a socialist harmonious society(a) grasp the theme of the purpose of the activity. The go ahead with the motherland in the youth, and XX with the development of

58、theme educational activities. Vigorously promote patriotism as the core of the national spirit and reform and innovation as the core spirit of the times, the combination of youth with common ideals and beliefs, with great achievements in socialist modernization the motivation of youth, the youth to

59、enhance self-confidence, sense of mission and responsibility to educate and guide the youth to personal pursuit into the common pursuit of all people, their personal struggle into the great practice of building socialism China characteristics, further firmly follow the party China characteristics Th

60、e confidence and determination of the socialist road, and build the common ideological foundation of the young people to build a socialist harmonious society.(two) rich theme activities. By carrying out the two generation dialogue , in my eyes, the charm of XX situation and policy through activities

61、 such as lectures, report, seminars, theatrical performances, mass cultural activities, to help young people understand Chinas reform and opening up the extraordinary journey and brilliant achievements achieved fruitful results, to understand the citys economic and social development since the new X

62、X, so that young people understand, love the new XX, and then to the construction of the new XX, a firm with the party on the road to socialism with China characteristics of faith; make full use of the 54, 61, National Day and the commemoration of the 85 anniversary of the founding of the red In the

63、 70 anniversary of the victory of the long march and other major activities, the favorable opportunity of major events and major festivals, to carry out educational activities, promote the theme education activities continue to create momentum, the rise of high tide, popular. Further study, promotio

64、n of Scientific Outlook on Development, to carry out a wide range of situation and policy education, the development prospect of the future of the motherland and XX, guiding the youth to continue enhance the sense of mission and responsibility, in the implementation of the 11th Five-Year planning an

65、d building a well-off society in the historical process of contributions. Be enthusiastic and press on.Three, to lead the trend of youth service, cultural city youth culture is taking action, and promote new progress in the construction of youth 12 / 12organization system and working mode, the selection of a number of municipal strengthening group to build innovation and