混合結(jié)構(gòu)中PBL剪力鍵群的力學(xué)特性研究
發(fā)布時(shí)間：2018-09-01 09:46
【摘要】：論文首先總結(jié)了當(dāng)前PBL剪力鍵的研究成果,并在此基礎(chǔ)上,設(shè)計(jì)了3批次28組較大規(guī)模的PBL剪力鍵試驗(yàn),深入研究混合結(jié)構(gòu)中PBL剪力鍵的靜力性能及變形特征,揭示PBL剪力鍵的承載機(jī)理,厘清剪力鍵群與單個(gè)剪力鍵之間的內(nèi)在關(guān)系,精確評估混合結(jié)構(gòu)PBL剪力鍵群的極限承載能力,探索PBL剪力鍵群的荷載傳遞規(guī)律,提出適合于工程計(jì)算的PBL剪力鍵群荷載傳遞模型。為此,主要完成了以下六個(gè)方面的研究工作：(1)為獲得剪力鍵內(nèi)鋼筋混凝土榫及垂直于開孔板面的約束等微觀力學(xué)特征,引入分布式傳感光纖測試系統(tǒng),有效地捕捉了PBL剪力鍵核心構(gòu)件的應(yīng)變分布特征；基于彈性地基梁理論和改進(jìn)的共軛梁理論,分析了穿孔鋼筋的力學(xué)行為和變形特性,提出了PBL剪力鍵屈服滑移的理論計(jì)算公式；基于對外圍混凝土中橫向鋼筋的分布式應(yīng)變測量,并結(jié)合理論分析,給出了PBL剪力鍵開孔板界而間豎向滑移與橫向膨脹變形的關(guān)系曲線,為剪力鍵承載機(jī)理的研究奠定了試驗(yàn)基礎(chǔ)。對承載機(jī)理試件的試驗(yàn)研究表明：在剪力鍵屈服滑移以前穿孔鋼筋的銷栓作用對剪力鍵的承載力貢獻(xiàn)較小,而在加載后期,由于穿孔鋼筋剪切曲折引起的“索效應(yīng)”使得銷栓作用漸趨明顯。(2)根據(jù)混凝土結(jié)合面的剪力傳遞理論,并結(jié)合有限元分析,闡明了基于剪力-摩擦理論的PBL剪力鍵的剪力承載機(jī)理,即：混凝土榫在外荷載作用下產(chǎn)生斷裂,斷裂面相對滑移時(shí)其骨料的相互嵌鎖導(dǎo)致界面間產(chǎn)生橫向膨脹變形,使得垂直于開孔板面約束鋼筋的反向夾持作用得到逐步發(fā)揮,進(jìn)而在開孔板開孔附近的橢圓形區(qū)域產(chǎn)生了較大的剪切—摩擦效應(yīng),連同開孔板界面間的粘聚力及穿孔鋼筋的插銷作用,構(gòu)成了混合結(jié)構(gòu)PBL剪力鍵承載力的三大組成部分�；趯旌辖Y(jié)構(gòu)PBL剪力鍵承載機(jī)理的分析,給出了PBL剪力鍵單鍵的極限承載力計(jì)算公式,與試驗(yàn)結(jié)果比較表明公式具有較高的精度。(3)混合結(jié)構(gòu)PBL剪力鍵與疊合梁PBL剪力鍵力學(xué)行為的主要區(qū)別來源于橫向約束的顯著不同,為此基于PBL剪力鍵承載機(jī)理的剪力-摩擦理論的相關(guān)限制條件,研究確定PBL剪力鍵橫向約束的上限和下限指標(biāo)；基于混凝土局部分析的拉壓桿模型和混凝土的局部承壓理論,提出了PBL剪力鍵合理構(gòu)造及具體指標(biāo)的計(jì)算公式,分析研究了多排剪力鍵避免劈裂破壞的理論最小間距需求,為工程設(shè)計(jì)和應(yīng)用提供理論支撐。(4)基于非線性有限元數(shù)值模擬方法,引入金屬材料的延性損傷及剪切損傷本構(gòu)模型,深入研究了多排PBL剪力鍵群中穿孔鋼筋的塑形變形、損傷發(fā)展及失效特性,給出了由穿孔鋼筋漸進(jìn)損傷導(dǎo)致的“索效應(yīng)”折減系數(shù)和剪力-摩擦效應(yīng)損傷折減系數(shù)的計(jì)算方法,提出PBL剪力鍵群極限承載能力的計(jì)算公式；基于大量的PBL剪力鍵的試驗(yàn)測試數(shù)據(jù),提出PBL剪力鍵彈性剛度的計(jì)算公式；結(jié)合剪力鍵的剪力-摩擦承載機(jī)理,綜合確定了混合結(jié)構(gòu)PBL剪力鍵群的正常使用極限狀態(tài)指標(biāo)；基于快速模擬退火算法,提出了準(zhǔn)確的多參數(shù)的PBL剪力鍵荷載-滑移本構(gòu)方程。(5)為明晰多排多列剪力鍵之間的相互影響,通過對穿孔鋼筋的夾持力作用的彈簧比擬,基于彈性地基板理論,提出了剪力鍵的影響作用半徑的計(jì)算公式。基于分布式光纖的剪力鍵開孔板應(yīng)變分布研究表明：開孔板面沿加載方向的空間應(yīng)變分布可退化為二維平面化的應(yīng)變分布；沿加載方向開孔板的歸一化應(yīng)變可采用Lorentz曲線來表征�；赑BL剪力鍵歸一化應(yīng)變的Lorentz分布曲線的數(shù)學(xué)特征,引入連續(xù)化的分析方法,推導(dǎo)了剪力鍵群豎向受力的基本微分方程,提出了PBL剪力鍵群荷載傳遞模型及其迭代算法。與試驗(yàn)結(jié)果對比表明,該算法計(jì)算方便、理論意義明確,具有足夠的工程精度。(6)為數(shù)值模擬剪力鍵群的承載能力及荷載傳遞行為,引入了ALE自適應(yīng)網(wǎng)格技術(shù)和子循環(huán)集成高級(jí)算法,進(jìn)行了混凝土材料特性擴(kuò)展的二次開發(fā),編寫了用戶自定義場變量子程序(USDFLD),實(shí)現(xiàn)了對混凝土剪脹角功能梯度模型的有效模擬,準(zhǔn)確模擬了混凝土榫的剪脹、穿孔鋼筋的損傷及剪力鍵的屈服強(qiáng)化特征,為PBL剪力鍵的有限元仿真分析提供了詳盡的參數(shù)取值及經(jīng)驗(yàn)借鑒。
[Abstract]:Firstly, the paper summarizes the current research results of PBL shear bonds, and on this basis, designs three batches of 28 groups of large-scale PBL shear bond tests, in-depth study of the static performance and deformation characteristics of PBL shear bonds in hybrid structures, reveals the bearing mechanism of PBL shear bonds, clarifies the internal relationship between shear bond groups and a single shear bond, accurate. This paper evaluates the ultimate bearing capacity of PBL shear bond groups in hybrid structures, explores the load transfer law of PBL shear bond groups, and proposes a load transfer model for PBL shear bond groups suitable for engineering calculation. Based on the elastic foundation beam theory and the improved conjugate beam theory, the mechanical behavior and deformation characteristics of perforated steel bar are analyzed, and the theoretical calculation formula of PBL shear bond yield slip is proposed. Distributed strain measurement of transverse reinforcing bars in peripheral concrete and theoretical analysis are carried out. The relationship between vertical slip and transverse expansion deformation of PBL shear bond perforated slab boundaries is given, which lays the experimental foundation for the study of shear bond loading mechanism. The pin-bolt effect of perforated steel bars contributes little to the bearing capacity of shear bonds, but the "cable effect" caused by the shear tortuosity of perforated steel bars makes the pin-bolt effect become more and more obvious in the later stage of loading. (2) According to the shear transfer theory of concrete joint surface and finite element analysis, the shear force of PBL shear bonds based on shear-friction theory is clarified. Load-bearing mechanism, that is, concrete tenon fracture under external load, the interlocking of the aggregate when the fracture surface relative slip, resulting in transverse expansion deformation between the interface, so that vertical to the orifice plate restraint bar reverse clamping effect is gradually exerted, and then in the vicinity of the orifice plate elliptical region produced a larger. The shear-friction effect, together with the cohesion between perforated plates and the pinning effect of perforated steel bars, constitutes three major components of the bearing capacity of PBL shear bonds in hybrid structures. (3) The main difference of mechanical behavior between PBL shear bonds of hybrid structures and composite beams is due to the significant difference of transverse constraints. Based on the shear-friction theory of PBL shear bonds, the upper and lower bounds of transverse constraints of PBL shear bonds are determined. Based on the partial analysis of the tension-compression bar model and the local compression theory of concrete, the calculation formulas of the reasonable construction and specific indexes of PBL shear bonds are proposed. The theoretical minimum spacing requirement of multi-row shear bonds to avoid splitting failure is analyzed and studied, which provides theoretical support for engineering design and application. (4) Based on the nonlinear finite element numerical simulation method, gold is introduced. The plastic deformation, damage development and failure characteristics of perforated steel bars in multi-row PBL shear bond groups are studied. The calculation methods of cable effect reduction coefficient and shear-friction damage reduction coefficient caused by progressive damage of perforated steel bars are given. The shear bond group poles of PBL are proposed. Based on a large number of test data of PBL shear keys, a formula for calculating the elastic stiffness of PBL shear keys is proposed. Combined with the shear-friction bearing mechanism of shear keys, the limit state index of PBL shear keys in hybrid structures is determined comprehensively. Based on the fast simulated annealing algorithm, an accurate limit state index is proposed. The load-slip constitutive equation of multi-parameter PBL shear bonds. (5) To clarify the interaction between multi-row and multi-row shear bonds, a formula for calculating the influence radius of shear bonds is proposed based on the elastic foundation plate theory through the spring analogy of the clamping force of perforated steel bars. The results show that the spatial strain distribution along the loading direction can be reduced to two-dimensional planar strain distribution, and the normalized strain along the loading direction can be represented by Lorentz curve. The load transfer model and its iterative algorithm of PBL shear bond group are presented. The results show that the algorithm is convenient to calculate, has clear theoretical significance and has sufficient engineering accuracy. (6) To simulate the bearing capacity and load transfer behavior of shear bond group numerically, the ALE adaptive grid technique is introduced. A user-defined field variable subroutine (USDFLD) was compiled to simulate the dilatancy angle function gradient model of concrete effectively. The dilatancy of tenon, the damage of perforated steel bar and the yielding and strengthening characteristics of shear keys were simulated accurately. The finite element simulation analysis of shear connectors provides detailed parameter values and experience.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：U441;U448.38
，
本文編號(hào)：2216819
[Abstract]:Firstly, the paper summarizes the current research results of PBL shear bonds, and on this basis, designs three batches of 28 groups of large-scale PBL shear bond tests, in-depth study of the static performance and deformation characteristics of PBL shear bonds in hybrid structures, reveals the bearing mechanism of PBL shear bonds, clarifies the internal relationship between shear bond groups and a single shear bond, accurate. This paper evaluates the ultimate bearing capacity of PBL shear bond groups in hybrid structures, explores the load transfer law of PBL shear bond groups, and proposes a load transfer model for PBL shear bond groups suitable for engineering calculation. Based on the elastic foundation beam theory and the improved conjugate beam theory, the mechanical behavior and deformation characteristics of perforated steel bar are analyzed, and the theoretical calculation formula of PBL shear bond yield slip is proposed. Distributed strain measurement of transverse reinforcing bars in peripheral concrete and theoretical analysis are carried out. The relationship between vertical slip and transverse expansion deformation of PBL shear bond perforated slab boundaries is given, which lays the experimental foundation for the study of shear bond loading mechanism. The pin-bolt effect of perforated steel bars contributes little to the bearing capacity of shear bonds, but the "cable effect" caused by the shear tortuosity of perforated steel bars makes the pin-bolt effect become more and more obvious in the later stage of loading. (2) According to the shear transfer theory of concrete joint surface and finite element analysis, the shear force of PBL shear bonds based on shear-friction theory is clarified. Load-bearing mechanism, that is, concrete tenon fracture under external load, the interlocking of the aggregate when the fracture surface relative slip, resulting in transverse expansion deformation between the interface, so that vertical to the orifice plate restraint bar reverse clamping effect is gradually exerted, and then in the vicinity of the orifice plate elliptical region produced a larger. The shear-friction effect, together with the cohesion between perforated plates and the pinning effect of perforated steel bars, constitutes three major components of the bearing capacity of PBL shear bonds in hybrid structures. (3) The main difference of mechanical behavior between PBL shear bonds of hybrid structures and composite beams is due to the significant difference of transverse constraints. Based on the shear-friction theory of PBL shear bonds, the upper and lower bounds of transverse constraints of PBL shear bonds are determined. Based on the partial analysis of the tension-compression bar model and the local compression theory of concrete, the calculation formulas of the reasonable construction and specific indexes of PBL shear bonds are proposed. The theoretical minimum spacing requirement of multi-row shear bonds to avoid splitting failure is analyzed and studied, which provides theoretical support for engineering design and application. (4) Based on the nonlinear finite element numerical simulation method, gold is introduced. The plastic deformation, damage development and failure characteristics of perforated steel bars in multi-row PBL shear bond groups are studied. The calculation methods of cable effect reduction coefficient and shear-friction damage reduction coefficient caused by progressive damage of perforated steel bars are given. The shear bond group poles of PBL are proposed. Based on a large number of test data of PBL shear keys, a formula for calculating the elastic stiffness of PBL shear keys is proposed. Combined with the shear-friction bearing mechanism of shear keys, the limit state index of PBL shear keys in hybrid structures is determined comprehensively. Based on the fast simulated annealing algorithm, an accurate limit state index is proposed. The load-slip constitutive equation of multi-parameter PBL shear bonds. (5) To clarify the interaction between multi-row and multi-row shear bonds, a formula for calculating the influence radius of shear bonds is proposed based on the elastic foundation plate theory through the spring analogy of the clamping force of perforated steel bars. The results show that the spatial strain distribution along the loading direction can be reduced to two-dimensional planar strain distribution, and the normalized strain along the loading direction can be represented by Lorentz curve. The load transfer model and its iterative algorithm of PBL shear bond group are presented. The results show that the algorithm is convenient to calculate, has clear theoretical significance and has sufficient engineering accuracy. (6) To simulate the bearing capacity and load transfer behavior of shear bond group numerically, the ALE adaptive grid technique is introduced. A user-defined field variable subroutine (USDFLD) was compiled to simulate the dilatancy angle function gradient model of concrete effectively. The dilatancy of tenon, the damage of perforated steel bar and the yielding and strengthening characteristics of shear keys were simulated accurately. The finite element simulation analysis of shear connectors provides detailed parameter values and experience.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：U441;U448.38
，
本文編號(hào)：2216819
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