摘要
随着大跨度空间钢结构在大型建筑中越来越广泛的应用,除了在设计理念方面的不断创新,在施工过程中也涌现出大量先进的施工工艺。由于这类结构空间跨度大,造型奇特,结构自身受力复杂;再加上施工过程难度大工期长,施工期间还会受到各种不确定因素的影响。结构施工过程中的受力状态与结构设计状态可能完全不同,如果按传统的结构设计方法进行设计,很难确保结构在施工过程中的安全。因此,有必要针对结构在施工过程中的受力情况进行系统研究,利用仿真模拟的方法分析了结构在施工阶段的力学特性,以保证工程安全、经济、有效的建设完成。
在施工过程中所遇到的技术性难题很多,本论文以某抬升裙楼为工程背景,在已有的国内外施工理论研究的基础上,利用有限元软件对抬升裙楼巨型悬挑钢桁架的卸载进行了模拟计算,重点分析了卸载过程中结构内力和位移的变化。论文的主要研究内容如下:
(1)鉴于建模需要,对临时支撑胎架进行了设计;
(2)利用ANSYS有限元软件,以一简单悬臂梁为例对悬挑结构的卸载进行模拟计算。设定四种卸载方案,对比分别按四种方案卸载时梁在支撑点处弯矩值和支撑反力的变化,分析不同卸载方式和卸载顺序对临时支撑受力及悬挑结构内力的影响,得出较为合理的卸载方式。
(3)通过简单模型的模拟计算,综合考虑其它方面因素后,确定采用由内到外分组分步卸载的方式进行卸载。结合大跨度空间悬挑钢桁架结构,对其建立有限元分析模型,分别按照“从内到外”及“从外到内”分组分步卸载的方式对结构实施卸载,然后进行对比分析并得出相关结论。
(4)通过上述分析,对该工程悬挑桁架的卸载提供指导性意见,并为其它类似工程提供参考。
With the large-span space steel structure used in a large building more and more widely, the design concept is being innovated and also a large number of advanced technologies are emerged in the process of construction. This type of structure with a large span and unusual shape has complex force of its own. Because the construction is very difficult and has a long duration, it will be subject to a variety of uncertain factors during the construction period. The force state is in an absolutely different state between structural design and construction. If the traditional method used for structural design, it is difficult to ensure the structural safety of the construction process. Therefore, it is necessary to carry out systematic research on force state of structure in the construction process and understand the mechanical characteristics of the structure using simulation methods, so that the building can be completed safely, economically and effectively.
There are many technical problems in the construction. The research background of this paper is podium uplift with giant cantilevered steel truss. Based on theoretical study at present, the unloading process is simulated by the finite element software to analyze internal forces and displacement changes. The main content of this paper is briefly summarized as follows:
(1) Temporary supports are designed as the view of modeling.
(2)The unloading of a simple cantilever beam is simulated using of ANSYS according to four unloading program. Compared with the calculation results from support reactions and internal force of trusses, a reasonable unloading program is received.
(3)Using simple simulation and considering the other factors, it is decided to adopt the stepped integral synchronous unloading "from inner to outer" and "from outer to inner" to unload supports. Finally, the calculation results are compared and analyzed.
(4)By analysis above, it provides the instructive suggestions to the supports unloading and the reference for other similar projects.
引文
[1]郭彦林,崔晓强.大跨度复杂钢结构施工过程中的若干技术问题及探讨[J].工业建筑,2004,34(12):1-5.
[2]沈世钊.大跨空间结构的发展—回顾与展望[J].土木工程学报,1998(6):20-25.
[3]董聪,王丽水,刘宪明.大跨体育场馆的研究与发展[J].《工程力学》增刊,2003:7-29.
[4]史洪泉.大跨度空间钢结构施工全过程力学分析及考虑施工影响的若干要素研究[D].博士学位论文,东南大学,2005:7-9.
[5]周观根,方敏勇.大跨度空间钢结构施工技术研究[J].施工技术,2006,35(12):82-87.
[6]Z.S.Makowski.Space Structure—A review of Development in last Decades.Space Structure IV,London,1993 vol82:325-346.
[7]蓝天.空间钢结构的应用与发展[J].建筑结构学报,2001,22(4):1-7.
[8]J.LMeek,H.S.Tan.Geometrically nonlinear analysis of space frames by an Incremental iterative technique.Computer methods in applied mechanics and engineering,1984,47:261-282.
[9]张晗.大跨度空间钢结构施工过程模拟与稳定性研究[D].硕士学位论文,武汉理工大学,2009:10-11.
[10]王光远.论时变结构力学[J].土木工程学报,2000,6:105-108.
[11]曹志远.施工力学与时变力学的数值分析[J].《计算力学学报》增刊,1997.
[12]李瑞礼.高层建筑结构施工力学分析的超级元—有限元耦合法[D].博士学位论文,同济大学,2001.
[13]C.Melbourne,P.Bullman.Load Relieving System,Proc.Int.Conf,On Non-conventional Structures,London,1987(2):1-6.
[14]喻永声.考虑建造过程的多重子结构分析矩阵位移法[J].计算结构力学及其应用,1990,7(3):36-44.
[15]吴建雄.大跨度空间结构考虑施工工况的设计方法研究[D].硕士学位论文,东南大学,2004.
[16]李瑞礼,曹志远.高层建筑结构施工力学分析[J].计算力学学报,1999,16(2):157-161.
[17]崔晓强,郭彦林,叶可明.大跨度钢结构施工过程的结构分析方法研究[J].工程力学,2006,23(5):83-89.
[18]罗尧治,赖达东等.国家大剧院钢壳体施工支撑体系的结构选型与设计[J].建筑结构,2003(11):61-63.
[19]伍小平,高振锋,李子旭等.国家大剧院钢壳体安装中卸载方案分析[J].建筑施工,2005,27(6):6-9.
[20]刘学军,周岱,黄真.上海新国际博览中心钢结构工程预应力施工技术研究.第十一届空间结构学术会论文集,2005.
[21]K.J.Bathe and H.Ozdemir.Elastic-plastic large deformation static and dynamic analysis.Computer and structures,1976,6:81-92.
[22]曹志远.土木工程分析的施工力学与时变力学基础[J].土木工程学报,2001,34(3):41-46.
[23]曹志远.时变力学及其工程应用力学与实践[J].力学与实践,1995,5:1-4.
[24]王光远.论时变结构力学[J].土木工程学报,2000,33(6):105-108.
[25]范志良.结构工程科学中若干计算结构力学问题的研究展望.力学进展,1994,24(3):391-399.
[26]刘满怀.球面网壳考虑施工影响的全过程受力分析[D].硕士学位论文,东南大学,2006.
[26]刘学武,郭彦林.考虑几何非线性钢结构施工力学分析方法[J].西安建筑科技大学学报(自然科学版),2008,40(2):161-170.
[27]卓新,董石麟.施工阶段内力与变位叠加法及其应用[J].浙江大学学报(工学版),2003,37(5):556-559.
[28]郭彦林,郭宇飞,刘学武.大跨度钢结构屋盖落架分析方法[J].建筑科学与工程学报,2007,24(1):52-59.
[29]伍小平,高振锋,李子旭.国家大剧院钢壳体施工全过程模拟分析.建筑结构学报,2005,26(5):40-46.
[30]郭彦林,刘学武.大跨度钢结构屋盖拆撑过程数值模拟的千斤顶—间隙单元法.西安建筑科技大学学报(自然科学版),2008,40(1):1-7.
[31]Majid K I.Forces and defluxions in changing structures[J].The Structural Engineer,1972,51(3).
[32]R.D.Wood and O.C.Zienkiewiez.Geometrically Non-linear Finite Element Analysis of Beams,Frames,Arches and Axsynmetric shells.Computers and Structures.1977,vol7:725-735.
[33]Mad A R.Numerical Simulation of the Segmental Construction of Three Dimensional Concrete Frames.Engineering Structures,2000,22:585-596.
[34]D.V.Rosowsky,Dryver R..Huston,Peter Fuhr,Wai-Fah.Chen.Measuring Formwork Lords during Construction[J].Concrete International,1994,16(11):35-56.
[35]Cruz P J S,Mad A R,Roca P.Nonlinear Time-Dependent Analysis of Segmentally ConstructedStructures.JournalofStructuralEngineering,ASCE,1998,124(3):278-286.
[36]尚晓江,邱峰.ANSYS结构有限元高级分析方法与范例应用(第二版)[M].北京:中国水利水电出版社,2008:314-324.
[37]丁阳.钢结构设计原理[M].天津:天津大学出版社,2004:148-149.
[38]颜卫亨.钢结构典型题解析及自测试题[M].西安:西安工业大学出版社,2002:160-166.
[39]Antonio R.Mad.Numerical simulation of the segmental construction of three dimensional concrete frames[J].Engineering structures,2000,22(6):66-75.
[40]Lew H S.Construction loads and load effects in concrete building construction[J].Concrete International,1995,17(4).
[41]郭彦林,郭宇飞,高巍,等.国家体育场钢结构屋盖落架过程模拟分析[J].施工技术,2006,35(12):36-40.
[42]邱德隆,李久林,杨俊峰等.国家体育场钢结构支撑卸载分析[J].施工技术,2006,35(12):32-36.
[44]Arulyunyan N K.Mathematical model of a dynamically accreted deformable body[J].Mechanics of Solide,1990,25(6):120-136.
[45]ReddyP,Ghaboussi J,Hawkings NM.Simulation of construction of cable stayed bridges[J].Journal of Bridge Engineering,1999,4(4):136-142.
[46]P.J.S.Cruz,etc.Nonlinear time-dependent analysis of segmentally constructed structures[J].Journal of structural engineering ASCE,1998,124(3):324-352.