基于人工神經(jīng)網(wǎng)絡(luò)的雙箍筋約束混凝土柱極限承載力影響參數(shù)分析
發(fā)布時(shí)間：2018-11-17 20:30
【摘要】：建筑行業(yè)在近十年的發(fā)展中相比之前發(fā)生了翻天覆地的變化,這種變化可以體現(xiàn)在兩個(gè)方面,其一是結(jié)構(gòu)復(fù)雜,其二是建筑層數(shù)逐年增加�；谝陨显�,對(duì)承重結(jié)構(gòu)性能的改善便成為了廣大設(shè)計(jì)人員關(guān)注的重點(diǎn)。就柱體而言,傳統(tǒng)的單箍筋約束混凝土柱已滿足不了結(jié)構(gòu)對(duì)承載力的要求,越來越多的學(xué)者開始將重心放在了對(duì)雙箍筋約束混凝土柱的研究上。其抗壓能力強(qiáng),極限承載力大的特點(diǎn)備受好評(píng)。然而,因?yàn)槠涫┕?fù)雜,制作成本高等因素的限制,在現(xiàn)場(chǎng)施工中很難看到它的身影。那么如何找到構(gòu)造中影響較小的因素,合理配置構(gòu)造形式達(dá)到節(jié)約成本的目的便成為了本文的研究課題。在整理近幾年的相關(guān)文獻(xiàn)時(shí),不難發(fā)現(xiàn)側(cè)重點(diǎn)多集中于受力特點(diǎn),結(jié)構(gòu)優(yōu)勢(shì)等因素。文章另辟蹊徑,在實(shí)驗(yàn)的基礎(chǔ)上利用神經(jīng)網(wǎng)絡(luò)對(duì)影響雙箍筋約束混凝土柱豎向極限承載力的七項(xiàng)參數(shù)進(jìn)行分析,并研究其影響特征。文章設(shè)計(jì)了9個(gè)內(nèi)圓外方雙箍筋約束混凝土柱,共分為三組,每組采用不同等級(jí)的混凝土。在箍筋配置上,以內(nèi)外層箍筋直徑,內(nèi)外層箍筋間距,內(nèi)外層箍筋配箍特征值,以及內(nèi)層箍筋圓直徑等七組變量作為研究對(duì)象。隨后分別對(duì)其施加豎向荷載,并初步探究各個(gè)參數(shù)對(duì)承載力的影響。實(shí)驗(yàn)結(jié)果表明:當(dāng)鋼筋強(qiáng)度,混凝土強(qiáng)度被控制在相同的條件下時(shí),適當(dāng)提高外層約束箍筋的配箍特征值,可以提高混凝土柱的延性;在一定程度內(nèi)提高混凝土的強(qiáng)度可以提高構(gòu)件的極限承載力。應(yīng)用ABAQUS有限元軟件對(duì)實(shí)驗(yàn)進(jìn)行驗(yàn)證和進(jìn)一步的研究。通過應(yīng)力分布圖發(fā)現(xiàn)了混凝土柱的受力機(jī)理:起初整個(gè)混凝土柱體類似于彈性構(gòu)件,此時(shí)的混凝土和縱筋共同承受壓力。隨后,混凝土和縱筋橫向變形膨脹,并將荷載傳遞給箍筋;在達(dá)到豎向極限承載力之前的一段時(shí)間內(nèi),荷載主要由箍筋承擔(dān)。在到達(dá)極限承載力后,鋼筋大部分處于屈服狀態(tài),形變?cè)鲩L(zhǎng)顯著;在模擬對(duì)比中發(fā)現(xiàn)只有第六組誤差較大,其他組均吻合良好。這一結(jié)果證明了實(shí)驗(yàn)的可靠性。通過人工神經(jīng)網(wǎng)絡(luò)對(duì)內(nèi)圓外方雙箍筋約束混凝土柱進(jìn)行模擬分析。結(jié)果表明:內(nèi)外層箍筋間距在一定范圍增大時(shí),構(gòu)件的極限承載力會(huì)隨之降低,外層箍筋間距變化時(shí)產(chǎn)生的影響更為顯著;當(dāng)內(nèi)外層箍筋直徑逐漸增大時(shí),約束混凝土構(gòu)件的豎向極限承載力并沒有表現(xiàn)出明顯的規(guī)律性變化;當(dāng)內(nèi)層箍筋圓直徑逐漸增大時(shí),柱體豎向極限承載力隨之減小;內(nèi)外配箍特征值在一定范圍增大時(shí),柱體的豎向承載力隨著配股特征值的增大而增大。這對(duì)更好的揭示影響其承載力的內(nèi)部參數(shù)因素和對(duì)控制工程的成本有著重要的理論和實(shí)際意義。
[Abstract]:Compared with the past ten years, the construction industry has undergone earth-shaking changes, which can be reflected in two aspects: one is the complexity of the structure, the other is the increase of the building floor number year by year. Based on the above reasons, the improvement of load-bearing structure performance has become the focus of attention of the majority of designers. As far as columns are concerned, the traditional concrete columns with single stirrups can not meet the requirements of the bearing capacity of the structure. More and more scholars begin to focus on the study of concrete columns with double stirrups. Its strong compressive capacity, the characteristics of large ultimate bearing capacity is highly praised. However, because of its complex construction, high production cost and other factors, it is difficult to see it in the field construction. So how to find the less influential factors in the structure, and how to reasonably allocate the structure form to achieve the purpose of cost saving has become the research topic of this paper. It is not difficult to find that the stress characteristics, structural advantages and other factors are the focal points in sorting out the relevant documents in recent years. On the basis of experiments, the paper analyzes the seven parameters which affect the vertical ultimate bearing capacity of concrete columns confined by double stirrups, and studies its influence characteristics. In this paper, 9 concrete columns with double stirrups are designed and divided into three groups. Each group uses concrete of different grades. In the configuration of stirrups, there are seven variables, such as the diameter of inner and outer stirrups, the spacing between inner and outer stirrups, the eigenvalues of stirrups, and the diameter of inner stirrups. Then the vertical load is applied to it, and the influence of each parameter on the bearing capacity is studied. The experimental results show that the ductility of concrete columns can be improved by properly increasing the hoop characteristic value of outer confined stirrups when the strength of steel bar and concrete strength are controlled under the same conditions. To a certain extent, the ultimate bearing capacity of members can be improved by increasing the strength of concrete. ABAQUS finite element software is used to verify the experiment and further research. The stress distribution diagram shows the stress mechanism of concrete columns: at first, the whole concrete column is similar to elastic members, and the concrete and longitudinal tendons are subjected to pressure together. Then the concrete and longitudinal tendons are deformed and expanded laterally and the load is transferred to the stirrups and the load is mainly borne by the stirrups during a period of time before the ultimate vertical bearing capacity is reached. After the ultimate bearing capacity is reached, most of the steel bars are in the yield state, and the deformation increases significantly. In the simulation comparison, only the sixth group has a larger error and the other groups are in good agreement with each other. This result proves the reliability of the experiment. The artificial neural network is used to simulate and analyze the confined concrete columns with double stirrups inside and outside the inner circle. The results show that when the internal and external stirrups spacing increases in a certain range, the ultimate bearing capacity of the members will decrease, and the influence of the outer stirrups spacing will be more significant. When the diameter of inner and outer stirrups increases gradually, the vertical ultimate bearing capacity of confined concrete members does not show obvious regularity, and when the diameter of inner stirrups increases gradually, the vertical ultimate bearing capacity of columns decreases. The vertical bearing capacity of the column increases with the increase of the eigenvalue of the internal and external hoop when the eigenvalue of the internal and external hoop increases in a certain range. It is of great theoretical and practical significance to better reveal the internal parameter factors that affect the bearing capacity and to control the cost of the project.
【學(xué)位授予單位】：吉林建筑大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TU375.3
[Abstract]:Compared with the past ten years, the construction industry has undergone earth-shaking changes, which can be reflected in two aspects: one is the complexity of the structure, the other is the increase of the building floor number year by year. Based on the above reasons, the improvement of load-bearing structure performance has become the focus of attention of the majority of designers. As far as columns are concerned, the traditional concrete columns with single stirrups can not meet the requirements of the bearing capacity of the structure. More and more scholars begin to focus on the study of concrete columns with double stirrups. Its strong compressive capacity, the characteristics of large ultimate bearing capacity is highly praised. However, because of its complex construction, high production cost and other factors, it is difficult to see it in the field construction. So how to find the less influential factors in the structure, and how to reasonably allocate the structure form to achieve the purpose of cost saving has become the research topic of this paper. It is not difficult to find that the stress characteristics, structural advantages and other factors are the focal points in sorting out the relevant documents in recent years. On the basis of experiments, the paper analyzes the seven parameters which affect the vertical ultimate bearing capacity of concrete columns confined by double stirrups, and studies its influence characteristics. In this paper, 9 concrete columns with double stirrups are designed and divided into three groups. Each group uses concrete of different grades. In the configuration of stirrups, there are seven variables, such as the diameter of inner and outer stirrups, the spacing between inner and outer stirrups, the eigenvalues of stirrups, and the diameter of inner stirrups. Then the vertical load is applied to it, and the influence of each parameter on the bearing capacity is studied. The experimental results show that the ductility of concrete columns can be improved by properly increasing the hoop characteristic value of outer confined stirrups when the strength of steel bar and concrete strength are controlled under the same conditions. To a certain extent, the ultimate bearing capacity of members can be improved by increasing the strength of concrete. ABAQUS finite element software is used to verify the experiment and further research. The stress distribution diagram shows the stress mechanism of concrete columns: at first, the whole concrete column is similar to elastic members, and the concrete and longitudinal tendons are subjected to pressure together. Then the concrete and longitudinal tendons are deformed and expanded laterally and the load is transferred to the stirrups and the load is mainly borne by the stirrups during a period of time before the ultimate vertical bearing capacity is reached. After the ultimate bearing capacity is reached, most of the steel bars are in the yield state, and the deformation increases significantly. In the simulation comparison, only the sixth group has a larger error and the other groups are in good agreement with each other. This result proves the reliability of the experiment. The artificial neural network is used to simulate and analyze the confined concrete columns with double stirrups inside and outside the inner circle. The results show that when the internal and external stirrups spacing increases in a certain range, the ultimate bearing capacity of the members will decrease, and the influence of the outer stirrups spacing will be more significant. When the diameter of inner and outer stirrups increases gradually, the vertical ultimate bearing capacity of confined concrete members does not show obvious regularity, and when the diameter of inner stirrups increases gradually, the vertical ultimate bearing capacity of columns decreases. The vertical bearing capacity of the column increases with the increase of the eigenvalue of the internal and external hoop when the eigenvalue of the internal and external hoop increases in a certain range. It is of great theoretical and practical significance to better reveal the internal parameter factors that affect the bearing capacity and to control the cost of the project.
【學(xué)位授予單位】：吉林建筑大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TU375.3
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