预制装配式叠合梁抗火性能研究

发布时间：2018-06-16 19:52

本文选题：预制装配式钢筋混凝土叠合梁 + 火灾　；参考：《苏州科技大学》2017年硕士论文

【摘要】：随着节能减排、保护环境要求的日益提高,以及劳动力成本的快速上涨,建筑产业现代化成为可持续发展道路的重要途径。作为建筑产业化的形式之一,装配式结构具有节能,环保,节省模板和缩短工期的优点,成为一个研究的热点。目前对钢筋混凝土叠合梁的研究主要集中于梁的静力性能和抗震性能,而对于钢筋混凝土叠合梁的抗火性能研究相对较少,对火灾高温下叠合梁抗火能力及安全性缺乏必要的认识。基于此,本文开展了预制装配式叠合梁抗火性能研究,主要研究工作如下:1.根据相关文献,整理了高温下混凝土和结构钢的材料特性,以尽可能符合实际为原则,选用了本文研究所用混凝土和钢材的热工参数和应力—应变关系。2.利用有限元软件ABAQUS验证了8根钢筋混凝土梁的温度场,在验证了模型合理性后,建立了叠合梁和现浇梁温度场模型,并将两者进行了对比分析。3.利用有限元软件ABAQUS验证了1根常温下叠合梁力学模型和3根高温下组合梁模型,在验证了模型合理性后,建立了叠合梁和现浇梁热-力耦合模型。4.根据有限元软件计算结果,分析了高温下叠合面摩擦系数、高温下叠合面滑移以及高温下叠合梁和现浇梁中受压区混凝土和纵筋应力随时间的变化规律,并将两者进行了对比分析,研究结果表明:由于叠合面大多数区域温度在400℃左右,因此高温下叠合面摩擦系数取为1,与常温下相同;高温下叠合面滑移明显大于相同条件常温下叠合梁;相同荷载比下,叠合梁受压区混凝土初始应力值要大于现浇梁的,且变化趋势不同,初始应力值随荷载比的增大而增大;相同荷载比下,叠合梁纵筋初始应力同样大于现浇梁的,变化趋势大致相似,初始应力值随荷载比的增大而增大;在相同荷载比下,叠合梁纵筋应力始终大于现浇梁的,出现“应力超前”现象。5.根据有限元软件计算结果,分析了荷载比、混凝土强度等级、箍筋配筋率、叠合参数Kh、剪跨比和受火面等参数对叠合梁耐火极限的影响,并将相同截面叠合梁和现浇梁的耐火极限进行对比分析,研究结果表明:随着荷载比的提高,叠合梁耐火极限降低;随着混凝土强度的提高,叠合梁耐火极限提高;箍筋配筋率对叠合梁耐火极限影响不显著;当叠合参数Kh小于一定数值时,叠合梁的耐火极限显著提高;存在一个最佳的剪跨比使得叠合梁耐火极限最大;受火面对叠合梁耐火极限影响显著,受火面越少相应叠合梁耐火极限越高。叠合梁的耐火极限略大于现浇梁。本文的研究成果有助于为预制装配式叠合梁抗火设计提供借鉴。
[Abstract]:With the increasing demand for energy saving and emission reduction and the rapid rise of the labor cost, the modernization of the construction industry has become an important way of the road of sustainable development. As one of the forms of building industrialization, the assembly structure has the advantages of energy saving, environmental protection, saving the template and shortening the time limit, and has become a hot spot of research. The study of reinforced concrete composite beams mainly focuses on the static and seismic performance of the beams, but the study on the fire resistance of the reinforced concrete composite beams is relatively few, and it lacks the necessary understanding of the fire resistance and safety of the laminated beams at high temperature. The research work is as follows: 1. according to the relevant literature, the material properties of concrete and structural steel at high temperature are collated, and the thermal parameters and stress-strain relationships of the concrete and steel used in this study are selected as possible, and the temperature field of 8 reinforced concrete beams is verified by the finite element software.2., which is verified. After the model is reasonable, the temperature field model of the laminated beam and the cast-in-place beam is established, and the two are compared and analyzed by.3.. The finite element software ABAQUS is used to verify the mechanical model of the laminated beam and the 3 composite beam model under the high temperature under the finite element software. After verifying the rationality of the model, the thermal force coupling model of the laminated beam and the cast-in-place beam is established by the finite element method (.4.), which is based on the finite element method (.4.). The calculation results of the meta software are used to analyze the friction coefficient of superposition surface at high temperature, the slip of overlapped surface at high temperature and the change law of the stress of concrete and longitudinal reinforcement in the compression zone of superposed beams and cast-in-place beams at high temperature, and the comparison and analysis are carried out. The results show that because most of the area temperature of the overlapped surface is about 400 degrees C, it is high. The friction coefficient of the laminated surface is 1, which is the same as that under normal temperature; the slip surface slip at high temperature is obviously greater than that under the same condition at normal temperature. Under the same load ratio, the initial stress value of the concrete in the compression zone of the laminated beam is greater than that of the cast-in-place beam, and the change trend is different, the initial stress value increases with the increase of the load ratio; under the same load ratio, the superposition is superimposed. The initial stress of beam longitudinal reinforcement is also larger than that of cast-in-place beam. The change trend is roughly similar, the initial stress value increases with the increase of load ratio. Under the same load ratio, the stress of the longitudinal reinforcement is always larger than that of the cast-in-place beam, and the phenomenon of "stress ahead" appears "stress ahead" phenomenon.5. analyses load ratio, concrete strength grade, and stirrup according to the calculation results of finite element software. The effects of the ratio of reinforcement, the Kh, the shear span ratio and the fire surface on the fire resistance limit of the laminated beams, and the comparison and analysis of the fire resistance of the laminated beams and the cast-in-situ beams are carried out. The results show that the fire resistance limit of the composite beams decreases with the increase of the load ratio; with the increase of the strength of the concrete, the fire resistance limit of the composite beams is improved; the stirrup of the stirrups is improved. The reinforcement ratio has no significant effect on the refractory limit of the laminated beam; when the superposition parameter Kh is less than a certain value, the fire resistance limit of the laminated beam is significantly improved; there is a optimum shear span ratio that makes the maximum fire resistance limit, the fire resistance of the laminated beam is significant, the less the fire face is, the higher the fire resistance limit of the laminated beam. The resistance of the laminated beam to the composite beam. The limit of fire is slightly larger than that of cast-in-place beams. The research results in this paper can help to provide reference for the fire resistance design of prefabricated composite beams.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU352.5

【参考文献】