摘要
利用MSC.MARC软件对火灾后型钢混凝土柱的截面温度场及剩余承载力进行了模拟分析,数值分析结果得到了试验验证。考虑混凝土强度、长细比、含钢率、荷载偏心率、受火时间等参数,利用MSC.MARC软件对ISO834标准火灾作用后型钢混凝土柱剩余承载力进行了进一步计算。计算结果表明,经历ISO834标准火灾作用后,型钢混凝土柱的极限承载力显著降低,在该文参数范围内,承载力降低幅度在8.5%~45.3%变化。定义火灾作用后型钢混凝土柱剩余承载力与常温下型钢混凝土柱极限承载力的比值k为火灾后型钢混凝土柱剩余承载力影响系数。数值模拟分析结果表明,混凝土强度、截面含钢率、受火时间对k值的影响较大,而长细比、偏心率对k值的影响相对较小。在数值计算结果基础上,通过回归分析的方法得到了火灾后型钢混凝土柱剩余承载力影响系数k的简化计算公式,公式计算结果与数值模拟分析结果符合较好。
The numerical simulating analysis for the sectional temperature field and residual load bearing capacity of steel reinforced concrete columns after exposure to fire is carried out by using element analysis software MSC.MARC. The simulating results are verified to be correct by test results. Then, the influence of parameters, such as concrete strength, slenderness, steel ratio, load eccentricity and temperature elevating time on residual load bearing capacity of steel reinforced concrete columns after exposure to ISO834 standard fire is studied by using MSC.MARC. Numerical simulating results show that the ultimate strength of steel reinforced concrete columns after exposure to ISO834 standard fire decrease remarkably, compared with that at normal room temperature. The decreasing degree is ranged from 8.5% to 45.3% in the parameters designed. The ratio of residual strength after exposure to fire to ultimate strength at normal room temperature of steel reinforced concrete columns is defined as residual-load-bearing-capacity influence coefficient k. Results from numerical simulation show that concrete strength, steel ratio, and temperature elevating time have remarkable influence on k, while slenderness and load eccentricity have little effect on k. The simplified calculating formula for k is put forward by a regression method in the base of numerical simulation results, and the calculating results from formula show that there is a well agreement between the analyzing results and numerical simulation results.
出处
《工程力学》
EI
CSCD
北大核心
2014年第S1期91-98,共8页
Engineering Mechanics
基金
国家自然科学基金项目(51178226)
宁波市自然科学基金项目(2013A610197)
宁波市重点学科项目(XKL11D2079)
关键词
火灾后
型钢混凝土
柱
温度场
剩余承载力
数值模拟
post-fire
steel reinforced concrete
columns
temperature field
residual load bearing capacity
numerical simulation
