型钢混凝土异形柱抗火性能研究及简化计算公式

发布时间：2018-05-02 17:01

本文选题：型钢混凝土异形柱 + 火灾　；参考：《青岛理工大学》2013年硕士论文

【摘要】：型钢混凝土异形柱不仅布置灵活、使用面积大，而且承载力高、抗震性能好。可以预见，型钢混凝土异形柱未来会在多、高层住宅建筑中得到广阔的应用。与钢筋混凝土异形柱的研究相比，我国型钢混凝土异形柱的抗火研究尚处于起步阶段。型钢混凝土异形柱由于其截面形状的不规则性，其正截面承载力的计算比矩形截面柱要复杂很多。为了保证火灾下柱子的安全性及了解高温下异形柱的力学性能，本文从试验研究、ABAQUS数值模拟、MATLAB程序编制和SRC异形柱承载力的简化计算四方面对SRC异形柱(包括十字形、T形、等肢L形和不等肢L形)火灾下的力学性能进行了系统分析。以下为本文的主要内容和成果： 1、本文在本团队成员的共同协作下设计了9根十字形、8根T形、9根等肢L形（简称DL形）、9根不等肢L形（简称BL形）型钢混凝土异形柱。对于每种截面形式的异形柱，其中8根（T形柱为7根）进行标准升温曲线下的火灾试验，作为对比另外1根进行常温下的轴压试验，得到截面温度场分布规律；对火灾后的试件进行静力加载试验，同时分析偏心距和荷载角对残余承载力的影响。试验结果表明：(1)测点距受火面越近，温度越高，升温幅度越大；反之，温度越低，升温幅度也越平缓。截面核心区测点的升温幅度较小，基本在200℃以下。(2)荷载角和偏心距对异形柱的受力性能有很大影响。无论何种截面形式异形柱，在其它条件一定的情况下，残余承载力随着偏心距的增大而减小，0°加载角的承载力高于45°加载角的承载力。(3)无论何种截面形式的型钢混凝土异形柱，其竖向变形和侧向位移大致都经历变形平缓、变形加速和变形急剧增加三个阶段。从抵抗变形的能力上看，在其他条件一定的条件下，十字柱优于T形柱，BL形柱优于DL形柱，T形柱优于DL形柱。(4)十字形柱的承载力是T形截面柱的1.15～1.5倍，BL形截面柱承载力是DL形截面柱的1.06～1.17倍左右，而DL形截面柱抵抗荷载的性能优于T形截面柱。 2、借助工程模拟有限元软件ABAQUS对型钢混凝土异形柱火灾后的温度场和高温下的受力性能进行了分析。结果表明：(1)ABAQUS模拟值与试验值吻合较好，能基本反映截面升温的一般规律。(2)试验侧移曲线与ABAQUS侧移曲线的变化形状是基本一致的，即随着偏心距的增大，X、Y向的侧移均呈现增大的趋势，而竖向侧移变化不大。(3)截面抗弯能力随着轴力的增大先增大后减小。试验得到的界限偏心距与ABAQUS计算得到的界限偏心距基本吻合。 3、根据平截面假定和数值分析原理，编制了适用于高温下型钢混凝土正截面承载力计算的MATLAB程序；运用该程序得到异形柱极限破坏时的N-M相关曲线和Mx-My相关曲线以及中性轴的位置，并分析型钢混凝土异形柱正截面承载力的影响因素：荷载角、偏心距、混凝土强度等级和配钢率等。结论如下：(1)由于程序的非线性，一般的数学解析法很难求解，本章采用Quasi-Newton方法，能快速有效的获得收敛解。(2)界限偏心距的试验值、ABAQUS值和MATLAB值吻合较好。(3)荷载角、配钢率、混凝土强度等级对型钢混凝土异形柱(包括十字形、T形、DL形和BL形)的极限承载力有着较大的影响。在其它因素一定的条件下，构件的极限承载力随含钢率的增大而增大，与混凝土强度等级呈正比，，随偏心距的增大而减小。(4)型钢混凝土异形柱与钢筋混凝土异形柱在受火1小时后的N-M包络图和Mx-My包络图的变化规律相近，而且配钢率的增加能显著提高异形柱的承载力。 4、根据本文的实验数据、模拟数据提出了适用于高温下型钢混凝土异形柱正截面承载力计算的折算截面法，并运用此法计算本文的试验构件来验证此法的可靠性。计算结果表明：(1)折算截面法对十字形、T形、BL形和DL形小偏压下是偏于安全的。(2)承载力四种算法的计算值吻合较好。
[Abstract]:Steel - concrete special - shaped columns are not only flexible , the use area is large , but also the bearing capacity is high , the anti - seismic performance is good . It can be predicted that the future of SRC special - shaped columns can be widely used in many high - rise residential buildings . Compared with the research of reinforced concrete special - shaped columns , the research on the anti - fire of SRC special - shaped columns is still in the initial stage .

In order to ensure the safety of columns under fire and to understand the mechanical properties of special - shaped columns under high temperature , this paper systematically analyzes the mechanical properties of SRC special - shaped columns ( including cross , T - shaped , etc . L - shape and unequal L - shape ) in order to ensure the safety of pillars under fire and to understand the mechanical properties of special - shaped columns under high temperature . The main contents and achievements of this paper are as follows :

1 . In this paper , 9 cross - shaped , 8 T - shaped , 9 equilateral L - shaped steel concrete special - shaped columns are designed under the co - operation of the members of the team .
The influence of eccentricity and load angle on the residual bearing capacity is analyzed . The experimental results show that : ( 1 ) the closer the measuring point is to the fire surface , the higher the temperature , the greater the temperature rise ;
( 3 ) The bearing capacity of the cross - section is 1 . 15 - 1.5 times of that of the T - shaped column , and the capacity of the T - shaped column is 1 . 06 - 1.17 times of that of the U - shaped cross - section column .

2 . The temperature field and the forced performance of SRC special - shaped column after fire are analyzed by means of finite element software of engineering simulation . The results show that : ( 1 ) The simulation value is in good agreement with the test value , which can reflect the general rule of the temperature rise of the section .

3 . Based on the principle of flat cross section assumption and numerical analysis , a MATLAB program is developed which is suitable for the calculation of bearing capacity of SRC concrete under high temperature .
The results are as follows : ( 1 ) Due to the nonlinearity of the program , the general mathematical analysis method is very difficult to solve . The conclusion is as follows : ( 1 ) Due to the nonlinearity of the program , the general mathematical analysis method is difficult to solve .

4 . According to the experimental data , this paper presents a method for calculating the normal section carrying capacity of SRC special - shaped columns under high temperature , and uses this method to calculate the reliability of this method .

【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU398.9;TU352.5

【参考文献】