（清华大学土木工程系，北京 100084

Numerical analysis and simulation of space

concrete frames under fire

CHEN Shicai, REN Aizhu, LU Xinzheng

(Department of Civil Engineering, Tsinghua University, Beijing 100084)

Abstract: Based on the fiber element model and layered shell element model developed and validated by the author, this paper establishes the numerical model for space concrete frames under fire. The connection relationship between the both element models is also considered and the overall analysis process of space concrete frames under fire is accomplished by a system (RCFire) developed for analyzing the overall behavior of structures under fire. To consider the non-uniform temperature distribution and material nonlinearity, the across-sections of the both elements are subdivided into many small fibers or layers. Finally, a concrete frame structure under fire is analyzed and the response regularity is investigated. The results can be used as the reference for the fire safety design of building structures under fire.

Key words: fire response; space concrete frame; element model; numerical simulation

1 RCFire系统框架与功能模块

RCFire系统采用了有限元软件开发设计方法，进行结构化模块设计，是一个主要用于建筑结构热分析与结构热力反应分析的系统工具。其主要功能模块有：模型建立模块；常规荷载与火灾荷载施加模块；热分析模块；热力分析模块；结果处理模块。

 图1 RCFire系统框架图 Fig. 1 The framework of RCFire system

2 数值模型

 =

 +

a                        b                                       c

2 纤维梁与分层壳单元及其连接模型

Fig. 2 Fiber beam and layered shell model and their connection

3 考虑楼板的混凝土框架结构火灾反应分析

 图3 结构梁柱布置以及受火房间情况 Fig. 3  Lay out of concrete frame and location of the fire

 a                                              b 图4 RCFire中的结构有限元模型以及常温下的计算结果 Fig. 4  FE model in RCFire and the results under normal temperature

 a                                    b                      c                                       d      图5 火灾下结构的反应 Fig.5  Fire response of the frame structure under fire

 a                                             b 图6 结构火灾反应中的压膜力以及变形图 Fig. 6 Membrane force and displacements for the structure under fire

6 结论

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[3] Ma KY, Richard LJY. Nonlinear plastic hinge analysis of three-dimensional steel frames in fire [J]. Journal of Structural Engineering, 2004, 130(7), 981-990.

[4] Souza V, Creus GJ, Simplified elastoplastic analysis of general frames on fire [J]. Engineering Structures, 2007, 29(4), 511-518.

[5] 过镇海,时旭东.钢筋混凝土的高温性能及其计算 [M]. 清华大学出版社.2003.

[6] Chen SC, Ren AZ. A Fire simulation of reinforced concrete frame structures for the thermal and structural analysis[C]. Proc. INCITE/ITCSED, New Delhi, India,2006, 125-137

 [7] Chen SC, Lu XZ, Ren A.Z. Fiber Beam Element Model for the Collapse Simulation of Concrete Structures under Fire[C]. COMPUTATIONAL MECHANIC, ISCM2007, Beijing, China, 2007, 288-298. [8] MacNeal S. MSC/ PATRAN version 8.0, us2er’s guide volume 4[M]. USA: MSC Corporation, 1998   基金项目：国家“十一五”支撑计划(No. 2006BAK01A02-09)和清华大学基础研究基金(No.JC2007003) 作者简介：陈适才(1979)，男，博士研究生，研究方向：结构抗火. E-mail: chensc04@mails.tsinghua.edu.cn
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