【摘要】：鋼-混凝土組合梁能夠充分發(fā)揮兩種材料的優(yōu)勢(shì)并限制其劣勢(shì),提高結(jié)構(gòu)的承載力、剛度和延性等性能。但混凝土的收縮、徐變會(huì)導(dǎo)致結(jié)構(gòu)產(chǎn)生復(fù)雜的長(zhǎng)期效應(yīng),包括不同材料間的截面應(yīng)力重分布、超靜定結(jié)構(gòu)的內(nèi)力重分布以及組合梁中的附加變形。通常情況下,長(zhǎng)期效應(yīng)引起的組合梁附加內(nèi)力會(huì)導(dǎo)致混凝土受拉,鋼結(jié)構(gòu)受壓,對(duì)結(jié)構(gòu)產(chǎn)生不利的影響。因此,合理預(yù)測(cè)并評(píng)估組合梁的長(zhǎng)期效應(yīng),對(duì)于確保結(jié)構(gòu)的安全性并提高計(jì)算分析方法的準(zhǔn)確性具有重要意義。針對(duì)現(xiàn)有方法不能合理反映組合梁翼板內(nèi)混凝土收縮應(yīng)力的空間分布特征,以及缺少有效的混凝土收縮應(yīng)力測(cè)試方法等問(wèn)題,本論文重點(diǎn)研究了收縮應(yīng)力的分析方法和測(cè)試方法,主要工作和成果包括:(1)通過(guò)文獻(xiàn)調(diào)研總結(jié)出混凝土的長(zhǎng)期材料特性以及其用于力學(xué)計(jì)算時(shí)采用的方法。其中,主要考慮的混凝土材料長(zhǎng)期性能為混凝土硬化過(guò)程中的彈性模量發(fā)展、混凝土收縮以及由收縮應(yīng)力引起的次生徐變效應(yīng)。(2)為了對(duì)研究問(wèn)題進(jìn)行簡(jiǎn)化,明確分析對(duì)象為一簡(jiǎn)支組合梁,并在現(xiàn)有方法的基礎(chǔ)上,進(jìn)一步考慮混凝土板寬度對(duì)收縮應(yīng)力大小的影響,利用組合結(jié)構(gòu)中常用的有效寬度的概念,提出改進(jìn)的計(jì)算方法,并將該方法與有限元對(duì)比驗(yàn)證其準(zhǔn)確性。如有必要,可以利用有限元結(jié)果對(duì)理論分析方法進(jìn)行修正。(3)根據(jù)以上提出的方法,設(shè)定參數(shù),對(duì)一個(gè)具體算例進(jìn)行附加內(nèi)力和應(yīng)力的分析,為工程中應(yīng)用提供參考。(4)設(shè)計(jì)試驗(yàn),對(duì)組合梁內(nèi)部應(yīng)力的測(cè)量方法進(jìn)行研究。收縮徐變引起的組合梁內(nèi)部應(yīng)力難以通過(guò)傳統(tǒng)測(cè)量方法測(cè)出,因此本文中通過(guò)文獻(xiàn)調(diào)研找出測(cè)量該應(yīng)力的有效方法,并設(shè)計(jì)試驗(yàn)加以驗(yàn)證。同時(shí)建立有限元模型與試驗(yàn)進(jìn)行對(duì)比,為進(jìn)一步的組合梁內(nèi)部附加應(yīng)力的測(cè)量打下基礎(chǔ)。本論文最后提出一種定量計(jì)算混凝土收縮徐變性能對(duì)組合梁內(nèi)力影響的計(jì)算方法,并應(yīng)用于工程實(shí)踐。
[Abstract]:Steel-concrete composite beams can give full play to the advantages and disadvantages of the two materials, and improve the bearing capacity, stiffness and ductility of the structure. However, the shrinkage and creep of concrete will lead to complex long-term effects, including the redistribution of cross-section stress between different materials, the redistribution of internal force of statically indeterminate structures and the additional deformation in composite beams. In general, the additional internal force of composite beam caused by long-term effect will lead to concrete tension and steel structure compression, which will have a negative effect on the structure. Therefore, it is of great significance to predict and evaluate the long-term effect of composite beam reasonably in order to ensure the safety of structure and improve the accuracy of calculation and analysis method. The existing methods can not reasonably reflect the spatial distribution characteristics of concrete shrinkage stress in the flange of composite beam and the lack of effective concrete shrinkage stress measurement method. This paper focuses on the analysis and measurement of shrinkage stress. The main work and results are as follows: (1) the long-term material characteristics of concrete and the methods used in mechanical calculation are summarized through literature research. Among them, the long-term properties of concrete are the development of elastic modulus in the process of concrete hardening, the shrinkage of concrete and the secondary creep effect caused by shrinkage stress. (2) in order to simplify the research, The object of analysis is a simply supported composite beam. On the basis of the existing methods, the influence of the width of concrete slab on the shrinkage stress is further considered. Using the concept of effective width commonly used in the composite structure, an improved calculation method is put forward. The accuracy of the method is verified by comparing it with finite element method. If necessary, the finite element results can be used to modify the theoretical analysis method. (3) according to the above method, the parameters are set, and the additional internal force and stress are analyzed for a concrete example. (4) Design test. The measurement method of internal stress of composite beam is studied. The internal stress of composite beam caused by shrinkage and creep is difficult to be measured by the traditional measurement method, so the effective method of measuring the stress is found out by literature investigation in this paper, and the experiment is designed to verify it. At the same time, the finite element model is established and compared with the test, which lays the foundation for the further measurement of the additional stress in the composite beam. In the end of this paper, a quantitative method for calculating the effect of shrinkage and creep behavior of concrete on the internal force of composite beam is proposed and applied to engineering practice.
【學(xué)位授予單位】：清華大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU398.9

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