本文選題：鋼筋混凝土構件　切入點：統(tǒng)一破壞方程　出處：《上海交通大學》2014年博士論文　論文類型：學位論文

【摘要】：在各種災害作用下，鋼筋混凝土構件的復雜受力實際是由軸力、彎矩、剪力、扭矩的不同組合形成，其破壞機理十分復雜。目前，除軸力、彎矩單一受力情況國內外有比較統(tǒng)一的計算方法外，對剪、扭加入引起的破壞理論并不統(tǒng)一。長期以來，國內外研究學者對鋼筋混凝土構件在復合受力作用下的研究已取得許多成果。一些靠試驗數(shù)據回歸得到的承載力計算公式，如我國現(xiàn)行的鋼筋混凝土結構設計規(guī)范，缺少統(tǒng)一的理論基礎，各回歸公式之間也不存在內在聯(lián)系。多年來，眾學者一直致力于鋼筋混凝土構件組合受力統(tǒng)一破壞理論的研究,利用協(xié)調，平衡和本構關系對構件受復合力作用進行全過程分析，取得了一些領先的成果。目前僅有這種理論可以分析鋼筋混凝土構件受拉-壓彎剪扭作用的破壞機理，但由于在計算中引入協(xié)調條件使計算變得復雜，讓工程界難以接受。一個成熟的理論，它應該在理論上是統(tǒng)一的，在表達上是簡明的�？傊�，與相對完善和成熟的鋼結構計算理論相比，鋼筋混凝土構件在復合力作用下的破壞理論還不夠成熟。 為方便工程應用，尤其是分析構件在災難荷載作用下的破壞，本文針對量大面廣的矩形斷面的鋼筋混凝土構件在軸力、彎矩、剪力、扭矩共同作用下的破壞提出了一個形式簡單并且能展示構件破壞機理的統(tǒng)一理論。本文的理論利用了鋼筋和混凝土的破壞準則，尋找到承載力極限狀態(tài)下不違反邊界條件且滿足平衡條件的應力分布，從而得到構件承受復合力破壞時各個外力的相互關系。依據極限分析中下限解定理可知，本文得到的結果是一個偏于安全的極限下限解，本文尋找的極限應力狀態(tài)越接近實際情況，這個下限解應該越接近真實解。 根據大量試驗現(xiàn)象可知，構件在承受的軸壓力相對較小時，構件的混凝土隨著荷載的增大，首先出現(xiàn)裂縫，之后部分混凝土退出工作，剩余的混凝土和鋼筋繼續(xù)承擔的荷載越來越大，直到構件破壞，此類破壞為延性破壞；而在構件承受軸壓力相對較大時，在混凝土先被壓碎的同時構件也隨之完全破壞，幾乎沒有像延性破壞那樣的破壞發(fā)展階段，此類破壞為脆性破壞。本文在利用極限下限解定理建立統(tǒng)一破壞方程時，根據兩類破壞模式的不同機理，分別建立了破壞方程。 在研究延性破壞時本文建立了如下的分析思路：首先需要尋找到構件在極限狀態(tài)下的三維翹曲破壞面，其次描述出破壞面上的應力分布，最后根據平衡條件可以得到各個外力之間的相互關系。在研究極限狀態(tài)下的破壞面時，本文提出了一種全新的組成破壞面各邊角的計算方法，根據這個方法找到的破壞面不僅能夠描述構件在受復合力作用時的三維翹曲破壞面，還可以在構件承受單一荷載時較為準確地退化成簡單的破壞面。在尋找破壞面上的應力狀態(tài)時，本文對鋼筋和混凝土的貢獻分別進行了詳細的分析。通過對理論和試驗研究的分析，本文總結出破壞面上的鋼筋的貢獻，由于不需借助協(xié)調條件進行計算，表達簡單便于應用。破壞面上的混凝土分為受拉區(qū)和受壓區(qū)。受拉區(qū)的混凝土由于骨料咬合的作用在開裂后可繼續(xù)承擔部分外力，本文提出了一種簡便的計算方法，僅需一個可以簡單計算的折減系數(shù)kT，便可量化受拉開裂區(qū)混凝土的貢獻。對處于復雜應力狀態(tài)且受壓破壞的混凝土，可以用主應力空間混凝土三維破壞準則計算應力狀態(tài)。這樣，破壞面上的混凝土的應力分布得到了簡單并較為準確的量化。由于構件承受復合力的不同，受壓區(qū)不同，破壞面形態(tài)也不同，在分析不同破壞形態(tài)下的極限平衡條件后，構件受拉-壓彎剪扭作用下的破壞方程可以用非常簡明的方式表達出來，同時破壞方程還清晰的表現(xiàn)了各個外力間的相互關系。 脆性破壞的最明顯的特征是，隨著混凝土先被壓壞構件也破壞，此時混凝土的應力狀態(tài)直接決定著構件的狀態(tài)。根據破壞機理，本文尋找到了構件受復合力作用時的正應力和剪應力的分布，當混凝土的應力狀態(tài)滿足主應力空間內三維破壞準則時，認為構件破壞。得到的分析方法計算簡單，便于應用，并反映了構件破壞的最主要特征。 經和試驗結果對比后發(fā)現(xiàn)，本文得到的破壞理論與實際破壞情況吻合較好。 本文用相同的分析方法對更復雜的受力情況，即矩形截面鋼筋混凝土構件受雙向拉-壓彎剪扭作用時的破壞情況，進行了初步探索。和試驗對比發(fā)現(xiàn)，本文理論取得了比較理想的結果。 與現(xiàn)行混凝土結構設計規(guī)范相比，統(tǒng)一破壞理論不僅計算出的極限承載力更為準確，，還能展示出破壞時各個外力之間的相互作用關系。 與其他分析方法相比，能夠分析拉-壓彎剪扭共同作用的理論與數(shù)值方法都比十分繁瑣，不適于工程中推廣，而本文得到的統(tǒng)一破壞理論恰好彌補了這個工程應用中的空缺。 總之，本論文提出的矩形截面鋼筋混凝土構件受復合力作用下的統(tǒng)一破壞理論不僅能夠清晰合理的闡釋構件的破壞機理，并能快速便捷的分析出構件的極限承載力和破壞模式，對于推廣到工程實際應用中有重要的參考意義。
[Abstract]:In a variety of disasters under complicated stress of reinforced concrete members is actually by the axial force, bending moment, shear force, different combinations of torque formation, the failure mechanism is very complicated. At present, in addition to the axial force, bending force calculation method of single unified situation at home and abroad, to join the shear failure theory caused by torsion are not uniform. For a long time, domestic and foreign research scholars have made many achievements on the study of the reinforced concrete member in the composite under the action of stress. Some test data obtained by regression calculation formula for the bearing capacity, such as the current design specification for concrete reinforced concrete structure, the lack of a unified theoretical basis, the regression formulas there is no inherent relationship. Over the years, many scholars have been committed to the combination of reinforced concrete member stress theory, damage by using the unified coordination, balance and constitutive relation of components by the combined forces of the whole History analysis, has made some achievements. At present only the leading theory can analysis of reinforced concrete member subjected to tension bending shear failure mechanism of torsion effect, but due to the introduction of coordination conditions in the calculation of the calculation is complex, so that the engineering is difficult to accept. A mature theory, it should in theory be unified. The expression is simple. In short, compared with the steel structure is relatively perfect and mature calculation theory, the damage theory of reinforced concrete member in the composite force is not mature enough.
For the convenience of engineering application, especially in the role of disaster analysis of component loading damage of reinforced concrete members with rectangular section in view of the large volume of the axial force, bending moment, shear force and torque under the interaction of failure presents a simple form and can show the failure mechanism of the component theory unified the theory. Using the failure criterion of concrete and steel, find the bearing stress distribution of stress under the limit state does not violate the boundary conditions and satisfy the equilibrium conditions, resulting in failure of each component under combined force force relationship. According to the limit analysis in lower bound theorem, the results of this paper is a safe limit the lower bound solution, this paper tries to find the ultimate stress state is closer to the actual situation, the lower bound solution should be closer to the real solution.
According to the experimental results, the component in the axial pressure is relatively small, the concrete as the load increases, the first part of the concrete cracks, then quit working load of steel and concrete and the remaining continue to bear the larger component until broken, such as failure and ductile failure; in the structure under axial pressure relatively large, in the first concrete crushed the component also completely destroyed, almost no ductility failure like stage of development. So, this kind of damage is brittle failure. In this paper using limit limit solution to establish the unified equation theorem, according to the different mechanism of two kinds of failure modes, failure equations were established.
In the study of ductility damage analysis method is established in this paper are as follows: first of all need to find the component in the limit state of 3D warping failure surface, then describe the failure stress distribution on the surface, according to the balance conditions can get the relationship between the various forces. In the study of failure surface under the ultimate limit state, is proposed in this paper. A new composition of the failure surface of each corner of the calculation method, according to the failure surface this method can not only find the description of component in 3D by composite force warping failure surface, but also in the structure under single loads accurately to degenerate into a simple failure surface. The failure surface should be looking for the stress state, the contribution of steel and concrete are analyzed. Based on the theoretical analysis and experimental research, this paper summed up the failure surface of the reinforced contribution, not because of Need to be calculated by means of coordination condition, simple expression and easy to apply. The failure surface of the concrete is divided into tension and compression zone. The tension zone of concrete due to the effect of aggregate interlock can continue to take part in force after cracking, this paper presents a simple calculation method, only a simple calculation can fold the reduction coefficient of kT, can be quantified by concrete tensile cracking zone contribution. In the complex stress state and compressive failure of concrete, we can use the principal stress space dimensional concrete failure criterion to calculate the stress state. In this way, the failure surface of the concrete stress distribution have been quantified and more accurate. Because of simple components under complex stress of different compression zone, failure surface is different, in the analysis of the limit equilibrium condition of different failure modes under tension, Bending Shear Torsion equation under the action of a non member Jane often It is expressed in the way of the Ming, and the destruction of the equation clearly shows the relationship between various external forces.
The most obvious characteristic of brittle failure, with the first being crushed concrete components are also destroyed, at this time the concrete stress state directly determines the member state. According to the failure mechanism, this paper find the component stress of composite force and shear stress distribution, when the concrete stress state to meet the principal stress space three-dimensional failure criterion, that component analysis methods have been destroyed. The calculation is simple and convenient for application, and reflects the main features of the damage of components.
After comparison with the test results, it is found that the damage theory obtained in this paper is in good agreement with the actual failure conditions.
In this paper, the same analysis method is used to make a preliminary exploration of the more complex loading condition, that is, the failure condition of reinforced concrete members with rectangular section subjected to biaxial tension compression bending, shear and torsion. Compared with the experiment, it is found that the theory has achieved satisfactory results.
Compared with the existing code for design of concrete structures, the unified failure theory is more accurate than the calculated failure capacity. It can also show the interaction between external forces during failure.
Compared with other analytical methods, the theoretical and numerical methods for analyzing the combined action of tension, compression, bending, shear and torsion are more complicated than those of other methods, and are not suitable for engineering promotion. The unified failure theory obtained in this paper just fills up the vacancies in this engineering application.
In short, the failure mechanism of reinforced concrete members with rectangular section to explain the failure under the unified theory of composite force can not only clear and reasonable, and can fast and convenient analysis of bearing capacity and failure modes of structure limit, for promotion to have important reference for practical engineering application.

【學位授予單位】：上海交通大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TU375;TU312.1

【參考文獻】

相關期刊論文 前10條

1 劉西拉;陳溪;;關于建立拉/壓彎剪扭統(tǒng)一計算公式的討論[J];四川建筑科學研究;2012年01期

2 李宏,劉西拉;混凝土拉、剪臨界破壞及純剪強度[J];工程力學;1992年04期

3 劉彬;張建仁;王磊;羊日華;;鋼筋混凝土梁抗剪承載力計算理論綜述(下)[J];中外公路;2011年03期

4 劉彬;張建仁;王磊;羊日華;;鋼筋混凝土梁抗剪承載力計算理論綜述(上)[J];中外公路;2011年02期

5 康谷貽,鞏長江;單調及低周反復荷載作用下異形截面框架柱的受剪性能[J];建筑結構學報;1997年05期

6 劉立新;鋼筋混凝土深梁、短梁和淺梁受剪承載力的統(tǒng)一計算方法[J];建筑結構學報;1995年04期

7 沈殷,李國平,陳艾榮;鋼筋混凝土結構抗剪分析方法的發(fā)展[J];上海公路;2003年S1期

8 管品武,王博,徐澤晶;鋼筋混凝土構件抗剪承載力分析方法比較[J];世界地震工程;2002年03期

9 康谷貽;鋼筋混凝土構件抗扭強度的塑性解[J];天津大學學報;1987年01期

10 劉西拉,籍孝廣;混凝土本構模型的研究[J];土木工程學報;1989年03期

相關博士學位論文 前1條

1 駱華勛;鋼筋均勻分布的混凝土構件破壞面統(tǒng)一模型的研究[D];上海交通大學;2012年

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