發(fā)布時間：2018-05-27 06:39

  本文選題：矩形鋼管混凝土柱 + 勁化帶��； 參考：《華南理工大學》2014年博士論文

【摘要】：矩形鋼管混凝土的鋼管對核心混凝土約束主要集中在角部，在四個側邊中部約束作用較小，所以矩形鋼管對核心混凝土的整體約束效應遠不及圓形鋼管混凝土，導致其承載力遠低于圓形鋼管混凝土柱。與方形鋼管混凝土相比，矩形鋼管截面長寬邊長不同，長邊對核心混凝土的約束作用弱，較短邊更易發(fā)生局部屈曲。但由于約束作用的存在，只要設置得當，其承載力比按鋼管和混凝土兩種材料單軸強度簡單疊加計算要高。 為了改善矩形截面鋼管混凝土柱構件的力學性能，在矩形截面鋼管混凝土柱中沿縱向每隔一定間距的橫截面上設置橫向水平約束拉桿（鋼筋），一方面能限制該部位核心混凝土的橫向變形，另一方面能為鋼管提供側向支撐作用而使鋼板的局部屈曲強度提高。約束拉桿的設置能極大改進矩形鋼管混凝土柱的力學性能，但約束拉桿之間區(qū)域仍出現彈塑性局部屈曲現象，，對內填混凝土的約束作用受到削弱。 勁化矩形鋼管混凝土柱通過加設勁化帶形成勁化帶與約束拉桿的和諧搭配，在增加極少用鋼量又不增加施工難度，影響施工進度的情況下，最大限度的減緩約束拉桿之間的彈塑性屈曲，提高側面約束能力，改善矩形鋼管混凝土柱的力學性能。 本文對矩形鋼管混凝土柱的勁化設計，基于已有研究成果，在滿足高層建筑結構安全的前提下，能較大限度地用較薄的鋼板厚度，實現較高的強度、剛度以及延性。 基于上述分析，本文對勁化矩形鋼管混凝土柱的軸壓、偏壓、滯回性能進行了系列研究。 (1)以約束拉桿水平間距、縱向間距、勁化帶截面、勁化帶設置方式為研究參數，共進行10個方形鋼管混凝土柱試件的軸壓承載力試驗。分析各參數對試件的破壞形態(tài)、受力特點、應變特點、承載力及延性等力學性能的影響，為后述的研究提供基本試驗資料。 (2)以鋼板厚度、約束拉桿直徑、約束拉桿強度、勁化帶截面、勁化帶設置方式為研究參數，采用擬靜力試驗方法對構件施加低周水平力反復荷載作用，共進行16個方形鋼管混凝土柱試件的低周水平力反復荷載試驗。分析在不同參數下，各個構件的滯回曲線、骨架曲線，從而計算出各個構件的承載力及其退化，剛度及其退化、位移延性系數、耗能能力。由試驗結果采用三折線計算模型回歸分析、確定了勁化方鋼管混凝土柱的骨架曲線模型參數，為這種新型構件在超高層工程中設計分析提供參考。 (3)對勁化矩形鋼管混凝土柱的約束機理進行了分析。矩形鋼管截面長邊、短邊對混凝土約束作用大小不同，及約束拉桿沿長邊、短邊布置數量不同。基于核心混凝土真三軸受壓的特點，提出了勁化矩形鋼板內核心混凝土的等效單軸本構關系。采用該本構關系對勁化矩形鋼管混凝土軸壓構件的荷載-變形關系曲線進行全過程數值分析，驗證了計算曲線與試驗曲線的吻合性。 (4)為與試驗監(jiān)測結果相互印證，根據本文提出的勁化矩形鋼板內填混凝土的本構關系，對所有試件進行了三維雙重非線性有限元分析，深入揭示勁化帶及約束拉桿對核心混凝土及鋼管應力分布的影響，對各個試件進行了對比。有限元分析結果與試驗結果基本相符。通過建立模型，擴大參數，利用有限元分析各種勁化方式、勁化參數下構件的側向約束效果。 (5)該類構件在各種勁化方式下的軸壓承載力有很大差別，不能用一個統一的公式表述。采用本文提出的勁化矩形鋼板混凝土本構關系，推導得出該類構件在各種勁化方式下的軸壓承載力計算公式。采用本文提出的勁化矩形鋼管混凝土柱的軸壓承載力計算公式對軸壓試件的承載力進行計算，計算結果與試驗結果、有限元分析結果吻合良好；基于已有研究成果，本文方法能合理地評估勁化矩形鋼管混凝土短柱的軸壓承載力。 (6)采用勁化矩形鋼管核心混凝土的本構關系，利用截面網格單元法對偏壓勁化矩形鋼管混凝土柱試件進行數值分析，并用有限元法進行了驗證，吻合良好，可以用來合理評估矩形鋼管混凝土短柱的偏壓承載力。
[Abstract]:The core concrete constraints of concrete-filled rectangular steel tube are mainly concentrated in the corner, and the confinement effect is less in the middle of the four sides, so the overall constraint effect of the rectangular steel pipe to the core concrete is far less than the circular concrete filled steel tube, which leads to its bearing force far below the circular steel pipe concrete column. Compared with the square steel tube concrete, the rectangular steel tube is compared. The length and width of the cross section is different, the long edge has a weak constraint on the core concrete, and the local buckling is easier to occur on the shorter side. However, because of the existence of the constraint, the bearing capacity is higher than the simple superposition of the uniaxial strength of the two kinds of steel tubes and concrete as long as the setting is proper.
In order to improve the mechanical properties of the rectangular section of the concrete filled steel tube column, the transverse horizontal restraint rod (steel bar) is set along the longitudinal cross section of the rectangular cross section concrete filled steel tube column. On the one hand, the transverse deformation of the core concrete can be restricted, and the other side can provide the lateral support for the steel pipe to make the steel plate. The local buckling strength of the confined bar can be improved greatly. However, the mechanical properties of the rectangular steel tube concrete column can be greatly improved, but the elastoplastic local buckling still appears in the zone between the restrained bars, and the restraining effect on the concrete is weakened.
The stiffening rectangular concrete-filled steel tube column is formed by adding the stiffening belt to form the harmonious collocation of the stiffening belt and the restraint rod. In the case of increasing the minimum steel quantity without increasing the construction difficulty and affecting the construction progress, the elastoplastic buckling of the restraint rod is restrained to the maximum limit, the lateral restraint ability is raised and the mechanics of the rectangular steel tube concrete column is improved. Performance.
In this paper, the stiffening design of rectangular concrete-filled steel tube column is based on the existing research results. On the premise of meeting the safety of the high-rise building structure, the thin steel plate thickness can be used to achieve higher strength, stiffness and ductility.
Based on the above analysis, the axial compression, bias and hysteretic behavior of rectangular concrete-filled steel tubular columns are studied in series.
(1) the axial compression bearing capacity test of 10 square concrete-filled steel tubular column specimens is carried out by restraining the horizontal spacing, longitudinal spacing, stiffening zone section and stiffening belt setting method as the research parameters. The effects of various parameters on the failure form, stress characteristics, strain characteristics, load bearing force and ductility of the specimens are analyzed to provide the following research. Basic test data.
(2) the low cycle horizontal force test of 16 square concrete-filled steel tube columns is carried out with the thickness of steel plate, constraint rod diameter, restraint tension bar strength, stiffening band cross section and stiffening belt setting method as the research parameters, and a total of 16 square steel tube concrete column specimens are tested under different parameters. The load-bearing capacity and its degradation, stiffness and its degradation, displacement ductility coefficient and energy dissipation capacity of each component are calculated by the hysteretic curve and skeleton curve of the component. The model parameters of the skeleton curve of the stiffened square steel tube concrete column are determined by the regression analysis of the three fold line calculation model, and the new component is used in the super high rise project. The design analysis provides reference.
(3) the constraint mechanism of the stiffened rectangular concrete-filled steel tube column is analyzed. The length of the rectangular steel tube is different from the long side and the short side to the concrete, and the number of the short side arrangement is different. Based on the characteristic of the true three axis compression of the core concrete, the equivalent uniaxial constitutive model of the core concrete in the stiffened rectangular steel plate is put forward. The relationship between the load deformation relation curve of the rigid rectangular concrete filled steel tube axial compression member is analyzed by the constitutive relation, and the agreement between the calculated curve and the test curve is verified.
(4) in order to verify the results of the test monitoring, according to the constitutive relation of the stiffened rectangular steel plate filled with concrete, the three-dimensional double nonlinear finite element analysis is carried out for all the specimens, and the effects of the stiffening belt and the restrained pull rod on the stress distribution of the core concrete and the steel pipe are deeply revealed. The analysis results are basically consistent with the experimental results. Through the establishment of the model, the parameters are expanded, the finite element method is used to analyze various stiffening methods and the lateral restraining effect of the component under the stiffening parameters.
(5) the axial compression bearing capacity of this kind of component is very different in various stiffening ways and can not be expressed by a unified formula. By using the constitutive relation of stiffened rectangular steel plate concrete proposed in this paper, the axial compression bearing capacity of this kind of member under various stiffening methods is derived. The stiffened rectangular concrete-filled steel tube is adopted in this paper. The calculation formula of the axial compression bearing capacity of the column is used to calculate the bearing capacity of the axial compression specimen. The calculation results are in good agreement with the experimental results and the finite element analysis results. Based on the existing research results, this method can reasonably evaluate the axial compressive bearing capacity of the stiffened rectangular concrete-filled steel tube short column.
(6) using the constitutive relation of the stiffened rectangular steel tube core concrete, the section grid element method is used to carry out numerical analysis of the eccentric compression stiffened rectangular concrete-filled steel tube column, and the finite element method is used to verify it. It is in good agreement and can be used to reasonably evaluate the bearing capacity of the rectangular concrete filled steel tube short column.
【學位授予單位】：華南理工大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TU398.9

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