本文選題：大面積混凝土　切入點(diǎn)：有限元　出處：《沈陽(yáng)建筑大學(xué)》2013年碩士論文

【摘要】：隨著制造業(yè)的飛速發(fā)展,廠房的建設(shè)規(guī)模在不斷地?cái)U(kuò)大,對(duì)于廠房地坪這種大面積混凝土的研究重點(diǎn)之一就是如何處理環(huán)境溫度和收縮作用引起的結(jié)構(gòu)開(kāi)裂,特別是在北方寒冷地區(qū),結(jié)構(gòu)投入使用前施工周期需要跨過(guò)一個(gè)采暖期的工程這一點(diǎn)非常重要。本文以實(shí)際工程為背景,通過(guò)理論和有限元軟件的分析計(jì)算,研究了大面積混凝土地坪的環(huán)境溫度效應(yīng)。 從已有的理論和工程實(shí)際出發(fā),本文在研究結(jié)構(gòu)環(huán)境溫度效應(yīng)過(guò)程中主要考慮了環(huán)境溫度變化、收縮和徐變等因素,確定了混凝土地坪的最不利溫差,最不利溫差包括環(huán)境溫度的整體變化和混凝土的收縮當(dāng)量溫差,并用理論公式和有限元軟件ABAQUS分別計(jì)算出了在最不利溫差下的溫度應(yīng)力,結(jié)果差異不大。 按照工程實(shí)際建立有限元模型進(jìn)行線彈性分析,分析中假定混凝土是連續(xù)均質(zhì)材料,地基不發(fā)生不均勻沉降,混凝土的彈性模量不隨時(shí)間變化。混凝土板的約束主要來(lái)自板與下部地基的摩擦作用。通過(guò)有限元分析得出的結(jié)果是：混凝土地坪板最大應(yīng)力出現(xiàn)在板的中間部位,從板中到板端應(yīng)力逐漸減小,這與實(shí)際工程中假縫切割后的混凝土板中間部位開(kāi)裂相符合,進(jìn)而可以說(shuō)明施工過(guò)程中假縫的切割尺寸不合理,切割后的混凝土板內(nèi)的溫度應(yīng)力仍大于混凝土的抗拉強(qiáng)度,造成混凝土開(kāi)裂。之后取不同尺寸的混凝土板在相同的約束條件和荷載下分別計(jì)算其內(nèi)部溫度應(yīng)力,通過(guò)比較最終得出比較合理的假縫切割尺寸為6m×4.5m。 最后通過(guò)改變混凝土板的長(zhǎng)度、厚度、混凝土強(qiáng)度等因素,分析這些因素對(duì)混凝土板的溫度應(yīng)力影響規(guī)律。
[Abstract]:With the rapid development of the manufacturing industry, the construction scale of the factory building is constantly expanding. One of the key points of the research on the large area concrete such as the workshop floor is how to deal with the structural cracking caused by the environmental temperature and shrinkage.Especially in the cold area of the north, it is very important that the construction cycle should cross a heating period before the structure is put into use.In this paper, the environmental temperature effect of large area concrete floor is studied by theoretical analysis and finite element software based on actual engineering.Based on the existing theory and engineering practice, this paper mainly considers the environmental temperature change, shrinkage and creep, and determines the most unfavorable temperature difference of concrete floor in the process of studying the structural environmental temperature effect.The most unfavorable temperature difference includes the whole change of ambient temperature and the shrinkage equivalent temperature difference of concrete. The temperature stress under the most unfavorable temperature difference is calculated by theoretical formula and finite element software ABAQUS.According to the engineering practice, the finite element model is established for linear elastic analysis. In the analysis, it is assumed that the concrete is a continuous homogeneous material, the foundation does not have uneven settlement, and the elastic modulus of concrete does not change with time.The constraint of concrete slabs mainly comes from the friction between the slabs and the subsoil.The results obtained by finite element analysis are as follows: the maximum stress of concrete floor slab appears in the middle part of the slab, and the stress decreases gradually from the middle of the slab to the end of the slab, which is consistent with the cracking in the middle part of the concrete slab after cutting the false joint in the actual engineering.It can be concluded that the cutting size of the artificial joint is unreasonable and the temperature stress in the cut concrete slab is still larger than the tensile strength of the concrete, which leads to the cracking of the concrete.Then the internal temperature stresses of concrete slabs with different sizes are calculated under the same constraint conditions and loads. The reasonable cutting size of false joint is 6m 脳 4.5m.Finally, by changing the length, thickness and strength of concrete slab, the influence of these factors on the temperature stress of concrete slab is analyzed.
【學(xué)位授予單位】：沈陽(yáng)建筑大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：TU755

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