本文選題：徐變　切入點(diǎn)：B3模型　出處：《北京交通大學(xué)》2008年碩士論文　論文類型：學(xué)位論文

【摘要】： 徐變是混凝土材料重要的長期性能,當(dāng)鋼筋混凝土梁在長期荷載作用下,徐變將使其撓度增加,并產(chǎn)生鋼筋與混凝土之間的應(yīng)力重分布,影響了結(jié)構(gòu)的適用性,以及安全性和耐久性。由于徐變對鋼筋混凝土梁力學(xué)性能的影響機(jī)理復(fù)雜,目前,這一問題還沒有得到合理地解決。 本文將基于固結(jié)理論的混凝土徐變B3模型運(yùn)用到鋼筋混凝土梁的計(jì)算中,結(jié)合鋼筋混凝土梁的受力特點(diǎn),建立了符合混凝土徐變微觀機(jī)理的鋼筋混凝土梁的徐變計(jì)算模型,進(jìn)而提出了鋼筋混凝土梁的長期撓度計(jì)算模型。模型考慮了鋼筋與混凝土之間的應(yīng)力重分布,以及受壓區(qū)混凝土高度隨時(shí)間的不斷變化。通過計(jì)算結(jié)果與試驗(yàn)數(shù)據(jù)相對比分析,可以看出基于B3模型的鋼筋混凝土徐變計(jì)算模型的結(jié)果與試驗(yàn)結(jié)果吻合良好,同時(shí)該模型較ACI、CEB-FIP等模型更加合理、準(zhǔn)確。 本文分析了配筋率(ρ)對鋼筋混凝土梁長期徐變變形的影響,得到鋼筋混凝土梁長期變形隨配筋率增大而較小的結(jié)論。此外,由于B3模型中考慮了混凝土配合比對徐變的影響,運(yùn)用此新建模型,本文分析了混凝土的水灰比(w/c)、骨料水泥比(a/c)、作用荷載等因素對鋼筋混凝土梁長期徐變變形的影響,并初步得到其規(guī)律:鋼筋混凝土梁的徐變隨混凝土水灰比的增長及作用荷載增大而提高,隨骨料水泥比的升高而有所降低。
[Abstract]:Creep is an important long-term performance of concrete material. When reinforced concrete beam is subjected to long-term load, creep will increase its deflection and produce stress redistribution between reinforcement and concrete, which affects the applicability of the structure. The influence of creep on the mechanical properties of reinforced concrete beams is complicated, so this problem has not been solved reasonably. In this paper, the concrete creep B3 model based on consolidation theory is applied to the calculation of reinforced concrete beam, and the creep calculation model of reinforced concrete beam is established, which accords with the microscopic mechanism of concrete creep, combined with the stress characteristics of reinforced concrete beam. Furthermore, a long-term deflection calculation model of reinforced concrete beams is proposed. The stress redistribution between reinforcement and concrete and the continuous variation of concrete height in compression zone are considered in the model. The calculated results are compared with the experimental data, and the calculated results are compared with the experimental data. It can be seen that the calculated results of RC creep model based on B3 model are in good agreement with the experimental results, and the model is more reasonable and accurate than the ACIN CEB-FIP model. In this paper, the effect of reinforcement ratio (蟻) on the long-term creep deformation of reinforced concrete beams is analyzed. It is concluded that the long-term deformation of reinforced concrete beams decreases with the reinforcement ratio increasing. In addition, the effect of concrete mix ratio on creep is considered in the B3 model. Based on the new model, the effects of water cement ratio (w / c), aggregate / cement ratio (a / c), and load on the creep deformation of reinforced concrete beams are analyzed in this paper. The creep of reinforced concrete beams increases with the increase of concrete water-cement ratio and the action load, and decreases with the increase of aggregate cement ratio.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2008
【分類號】：TU375.1

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前3條

1 宋延釗;貢江大橋施工預(yù)拱度不確定因素分析及控制[D];江西理工大學(xué);2011年

2 許康;混凝土收縮徐變試驗(yàn)研究[D];長沙理工大學(xué);2011年

3 李鵬飛;變化濕度下混凝土徐變及鋼筋砼梁長期性能研究[D];北方工業(yè)大學(xué);2012年

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本文編號：1562156