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  本文關(guān)鍵詞： 活性粉末混凝土 受彎構(gòu)件 開裂彎矩 抗彎承載力 剛度與裂縫寬度　出處：《西南交通大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：活性粉末混凝土(Reactive Powder Concrete,簡稱RPC)是一種具有高強度、高韌性和高耐久性等優(yōu)良性能的水泥基復(fù)合材料,具有廣闊的應(yīng)用前景。目前我國的研究主要集中在RPC材料性能方面,在RPC結(jié)構(gòu)方面的研究較少。由于RPC抗拉強度高,彈性模量大,將之與鋼正交橋疊合,只需要不大的厚度即可以顯著增大正交異性板的彎曲剛度,從而明顯減小疊合橋面板的自重。然而,將RPC應(yīng)用于疊合橋面板前,還有許多基礎(chǔ)工作要做。文中采用試驗結(jié)合理論分析的方法對RPC板(含疊合板)的抗彎性能進行研究,主要工作及結(jié)論如下：根據(jù)20塊RPC加筋板和16塊鋼-RPC疊合板的實測開裂彎矩,基于平截面假定,分別推導(dǎo)了二者的開裂彎矩計算公式。在此基礎(chǔ)上,利用文中及他人的實測數(shù)據(jù),采用回歸分析,建立了RPC抗拉強度關(guān)于鋼纖維體積摻量的計算公式�？紤]到二者均屬受彎構(gòu)件,建立了開裂彎矩統(tǒng)一計算公式。針對RPC材料當水泥基開裂后鋼纖維仍然可以承擔拉力的特點,推導(dǎo)了RPC加筋板受拉區(qū)開裂后的應(yīng)力折減系數(shù)的計算方法和受壓區(qū)等效應(yīng)力及等效受壓區(qū)高度的計算方法。在此基礎(chǔ)上,建立了RPC加筋板正截面抗彎承載力計算公式。同時,采用換算截面法,將鋼板換算成等厚的混凝土板,指出鋼-RPC疊合板中性軸分別位于鋼板和混凝土板的兩種受力模式,并分別得到了相應(yīng)承載力計算公式。文章同時推導(dǎo)了RPC加筋板的界限相對受壓區(qū)高度和界限配筋率�？紤]了受拉區(qū)RPC的貢獻,采用鋼筋實測應(yīng)變,求得正常使用階段各級荷載下縱向鋼筋拉力對壓區(qū)RPC合力作用點的力矩。通過對參數(shù)的回歸分析,推導(dǎo)了RPC加筋板剛度計算公式。考慮鋼筋保護層厚度的影響,結(jié)合鋼纖維混凝土裂縫寬度計算方法,建立RPC加筋板裂縫寬度計算公式。以鋼-RPC疊合板實測彎矩-撓度曲線反算疊合板實測剛度。基于有效慣性矩法,通過數(shù)值逼近,求得疊合板有效剛度計算公式,從而得到疊合板撓度計算公式。忽略鋼板與RPC板間滑移,通過引入裂縫開裂高度,參考鋼纖維混凝土裂縫寬度計算方法,得到疊合板負彎矩作用下的裂縫寬度計算公式。
[Abstract]:Reactive Powder reinforced concrete (RPCs) is a kind of cement matrix composite with high strength, high toughness and high durability, which has a wide application prospect. At present, the research in China is mainly focused on the properties of RPC materials. Due to the high tensile strength and large elastic modulus of RPC, the flexural stiffness of orthotropic plates can be significantly increased by overlaying it with steel orthotropic bridges with only a small thickness. However, there is still a lot of basic work to be done before the application of RPC to the composite deck slab. In this paper, the flexural properties of RPC slab (including laminated slab) are studied by means of experimental and theoretical analysis. The main work and conclusions are as follows: according to the measured cracking moment of 20 RPC stiffened plates and 16 steel RPC composite plates, based on the assumption of the plane section, the formulas for calculating the cracking moment of the two plates are derived respectively. Based on the measured data and regression analysis, a formula for calculating the volume content of steel fiber in RPC tensile strength is established. It is considered that both of them are flexural members. A unified formula for calculating crack bending moment is established. According to the characteristics of steel fiber can still bear tensile force when cement base cracks in RPC material, In this paper, the calculation method of stress reduction coefficient after crack of RPC stiffened plate under tension and the calculation method of equivalent stress and height of equivalent compression zone in compression zone are derived. On the basis of this, the formula for calculating flexural bearing capacity of normal section of RPC stiffened plate is established. By using the method of conversion section, the steel plate is converted into concrete slab of equal thickness, and the neutral axis of steel-RPC composite slab is pointed out, which is located in two stress modes of steel plate and concrete slab, respectively. At the same time, the height of the limit relative to the compression zone and the limit reinforcement ratio of the RPC stiffened plate are derived. Considering the contribution of the RPC in the tensile zone, the measured strain of the steel bar is used. The moment of longitudinal steel bar tension acting on the RPC joint force in compression zone under various loads in normal service stage is obtained. By regression analysis of the parameters, the stiffness calculation formula of RPC stiffened plate is derived. The influence of the thickness of steel protection layer on the stiffness of RPC stiffened slab is taken into account. Based on the calculation method of crack width of steel fiber reinforced concrete (SFRC), the formula for calculating crack width of RPC stiffened plate is established. The measured stiffness of composite plate is calculated by using the measured moment of bending curve of steel RPC composite plate. Based on the effective moment of inertia method, the method of numerical approximation is used to calculate the stiffness of the composite plate. The formula for calculating the effective stiffness of composite plate is obtained, and the formula for calculating deflection of composite plate is obtained. The slip between steel plate and RPC plate is ignored, and the crack crack height is introduced to calculate the crack width of steel fiber reinforced concrete (SFRC). The formula for calculating crack width of composite plate under negative bending moment is obtained.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TU37

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本文編號：1506019