【摘要】：在豎向荷載作用下,拱支承處產(chǎn)生的水平推力,使得拱肋截面彎矩顯著減小,以承受軸向壓力為主。鋼管混凝土材料以受壓為主,適合于在拱結(jié)構(gòu)中應(yīng)用。鋼管混凝土拱兼具承載力高、施工方便、造型美觀等優(yōu)點(diǎn),故在我國(guó)橋梁工程中取得了廣泛的應(yīng)用,并且近年來(lái)也得到了國(guó)外工程界的認(rèn)可。隨著施工技術(shù)的成熟,鋼管混凝土拱的跨度不斷增大,不利于拱肋的穩(wěn)定;同時(shí),現(xiàn)代橋梁結(jié)構(gòu)的造型愈加新穎、獨(dú)特,其平面外穩(wěn)定問(wèn)題尤為突出。在鋼管混凝土拱的平面外穩(wěn)定問(wèn)題中,其失穩(wěn)時(shí)是由軸力、平面內(nèi)及平面外彎矩、扭矩等共同作用導(dǎo)致的,截面應(yīng)力分布較為復(fù)雜,同時(shí)包括幾何非線性的影響,導(dǎo)致問(wèn)題進(jìn)一步復(fù)雜,相關(guān)研究比較少見(jiàn)。因此,針對(duì)鋼管混凝土拱的平面外穩(wěn)定問(wèn)題開(kāi)展研究工作,顯得迫切而必要。本文以工程中常見(jiàn)的鋼管混凝土拋物線拱為研究對(duì)象,對(duì)其在豎向荷載作用下的平面外穩(wěn)定性能展開(kāi)研究,具體內(nèi)容如下:(1)采用ABAQUS軟件建立鋼管混凝土拋物線拱的有限元模型,針對(duì)鋼管混凝土拱的結(jié)構(gòu)、材料特點(diǎn),以及平面外穩(wěn)定問(wèn)題的受力特點(diǎn),確定適合的單元類(lèi)型、材料應(yīng)力-應(yīng)變關(guān)系及分析方法,并考慮幾何-材料雙重非線性及幾何初始缺陷的影響。通過(guò)對(duì)比現(xiàn)有的鋼管混凝土拋物線拱平面外穩(wěn)定試驗(yàn)及鋼管混凝土格構(gòu)柱軸壓試驗(yàn)結(jié)果,驗(yàn)證本文采用有限元模型的正確性。(2)通過(guò)對(duì)目前工程中單圓管截面鋼管混凝土拱的統(tǒng)計(jì)分析,確定本文研究對(duì)象的幾何參數(shù),著重研究其平面外穩(wěn)定問(wèn)題的主要影響因素:含鋼率、長(zhǎng)細(xì)比及矢跨比。由荷載-位移全過(guò)程曲線的分析,得到其平面外穩(wěn)定承載力;由拱肋截面的變形及內(nèi)力分析,確定其發(fā)生平面外失穩(wěn)過(guò)程中的受力特點(diǎn),據(jù)此采用等效柱模型,確定其平面外穩(wěn)定系數(shù)計(jì)算公式。(3)針對(duì)工程常見(jiàn)的桁式截面鋼管混凝土拋物線拱,對(duì)其平面外穩(wěn)定性能展開(kāi)研究,截面形式有雙肢、三肢及四肢截面,主要分析參數(shù)有含鋼率、長(zhǎng)細(xì)比及矢跨比。在單圓管截面鋼管混凝土拱平面外穩(wěn)定性能研究的基礎(chǔ)上,針對(duì)桁式截面鋼管混凝土拱的結(jié)構(gòu)特點(diǎn)及受力特點(diǎn),對(duì)其在單位剪力作用下的平面外剪切變形進(jìn)行推導(dǎo),并建立考慮剪切變形影響的平面外穩(wěn)定設(shè)計(jì)公式。
[Abstract]:Under the vertical load, the horizontal thrust produced at the support of the arch makes the bending moment of the arch rib section decrease significantly, and the axial pressure is the main force. Concrete-filled steel tube material is mainly under compression, which is suitable for application in arch structure. Concrete-filled steel tube arch has the advantages of high bearing capacity, convenient construction and beautiful shape, so it has been widely used in bridge engineering in our country, and has been recognized by foreign engineering circles in recent years. With the maturity of construction technology, the span of concrete-filled steel tube arch is increasing, which is not conducive to the stability of arch rib. At the same time, the shape of modern bridge structure is more novel and unique, and the problem of out-of-plane stability is particularly prominent. In the out-of-plane stability of concrete-filled steel tubular arch, the instability is caused by the joint action of axial force, in-plane and out-of-plane bending moment, torque, etc. The problem is further complicated, and the related research is relatively rare. Therefore, it is urgent and necessary to study the stability of concrete-filled steel tubular arch. In this paper, the concrete filled steel tube parabola arch, which is commonly used in engineering, is taken as the research object, and its out-of-plane stability under vertical load is studied. The main contents are as follows: (1) the finite element model of concrete filled steel tubular parabola arch is established by using ABAQUS software. According to the structure, material characteristics and stress characteristics of the out-of-plane stability problem, the suitable element type is determined. The stress-strain relationship of materials and its analytical method are considered, and the effects of geometric material double nonlinearity and geometric initial defects are considered. By comparing the existing concrete filled steel tube (CFST) parabola arch external stability test and the axial compression test results of CFST lattice columns, The validity of the finite element model is verified. (2) through the statistical analysis of concrete filled steel tube arch with single circular pipe section in current engineering, the geometric parameters of the research object are determined. The main influencing factors of the out-of-plane stability are studied, such as steel content, aspect ratio and rise-span ratio. Based on the analysis of the load-displacement curve, the out-of-plane stability bearing capacity is obtained. Based on the analysis of deformation and internal force of arch rib section, the stress characteristics in the process of external instability of arch rib are determined, and the equivalent column model is adopted. The calculation formula of the out-of-plane stability coefficient is determined. (3) for the common truss section concrete-filled steel tube parabola arch, the out-of-plane stability of the arch is studied. The section forms are two-limb, three-limb and extremity section. The main analysis parameters are steel content ratio, aspect ratio and span ratio. Based on the study of the external stability of concrete filled steel tube arch with single circular section, the external shear deformation of concrete filled steel tube arch with truss section under the action of unit shear is deduced according to the structural characteristics and stress characteristics of concrete filled steel tube arch with truss section. The design formula of out-of-plane stability considering the influence of shear deformation is established.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：TU398.9
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本文編號(hào)：2413732