預應力混凝土曲線梁結構分析及病害防治
發(fā)布時間：2018-10-18 18:36
【摘要】：隨著我國城市軌道交通事業(yè)的迅速發(fā)展,預應力混凝土曲線梁橋得到了越來越多的應用。曲線梁橋是復雜的空間受力結構,“彎扭耦合”是其最顯著的受力特性。論文基于曲線橋的基本理論和有限元法,以北京地鐵十四號線跨豐沙鐵路橋為依托,詳細分析了預應力混凝土曲線梁的受力特點,總結了曲線半徑對曲梁力學行為的影響；針對曲線梁橋在施工和運營中常見的病害,著重研究了預應力荷載、溫度荷載對曲梁的作用效應,分析了腹板鋼束側崩、主梁“爬移”、支座脫空等病害的產生原因,提出了一些防治措施。 研究表明：在平面外豎向荷載作用下,即使是對稱荷載,曲梁內也會產生較大的扭轉力矩,發(fā)生相應的扭轉變形。這種扭轉作用使得曲梁內外兩側受力不均,主要表現(xiàn)為梁體內、外兩側的應力差異和抗扭雙支座中內、外側支座的反力差別。隨著半徑的減小,曲梁的扭轉力矩增大,梁體內外兩側的受力越不均勻,扭轉變形也更為劇烈。因此在曲線梁橋設計中,在滿足其他要求的前提下,應盡可能選用較大的曲線半徑。 當曲線半徑很小或張拉力很大時,預應力的徑向水平分布力容易造成施工時腹板鋼束的側向崩出,對此可采用預應力鋼束外移、增設防崩鋼筋、合理設置橫隔板、進行腹板防崩驗算等方法,從設計上防止此類病害的發(fā)生。預應力產生的扭轉作用和溫度荷載也是造成曲梁“爬移”、支座脫空的重要原因。設計時應預留足夠的伸縮縫變形量和支座允許變形量,保證曲梁沿切向的自由伸縮,同時采取一定的限位措施；對于支座脫空現(xiàn)象,可采取增大梁端支座間距,增強端部梁體抗扭性能的方法來處理。
[Abstract]:With the rapid development of urban rail transit in China, prestressed concrete curved girder bridge has been applied more and more. Curved girder bridge is a complicated spatial structure, and "bending and torsional coupling" is the most obvious force characteristic. Based on the basic theory of curved bridge and finite element method, based on the Fengsha railway bridge of Beijing metro line 14, the stress characteristics of prestressed concrete curved beam are analyzed in detail, and the influence of curve radius on the mechanical behavior of curved beam is summarized. In view of the common diseases of curved girder bridge in construction and operation, the effects of prestress load and temperature load on curved beam are studied, and the causes of web plate steel bundle side collapse, main beam "climbing and moving" and support detachment are analyzed. Some preventive measures are put forward. The results show that under the action of vertical load outside the plane, even the symmetrical load, the torsional moment in the curved beam will be larger and the corresponding torsional deformation will occur. This kind of torsion causes the internal and external forces of curved beam to be uneven, which mainly shows the stress difference in the inside and outside of the beam and the difference in the reaction force between the inner and outer supports of the double bearing with torsion. With the decrease of radius, the torsional moment of curved beam increases, and the force on both sides of the beam becomes more uneven, and the torsional deformation becomes more severe. Therefore, in the design of curved girder bridge, under the premise of satisfying other requirements, the larger curve radius should be chosen as far as possible. When the curve radius is very small or the tensile force is very large, the radial horizontal distribution force of prestressing force will easily cause the lateral collapse of web steel bundle during construction. For this reason, the prestressed steel bundle can be removed from the outside, the anti-avalanche steel bar is added, and the transverse partition plate is reasonably set up. In order to prevent the occurrence of this kind of disease, the methods of web anti-avalanche checking and so on are carried out. Torsion and temperature load caused by prestress are also the important reasons for "climbing and moving" of curved beam and void of support. Enough deformation of expansion joints and allowable deformation of supports should be reserved in design to ensure the free expansion of curved beams along the tangential direction, and certain limiting measures should be taken at the same time; for the phenomenon of support clearance, it is possible to increase the distance between the supports at the end of the beam, The method of strengthening the torsion resistance of the end beam body is used.
【學位授予單位】：北京交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U445.7;U441
本文編號：2280022
[Abstract]:With the rapid development of urban rail transit in China, prestressed concrete curved girder bridge has been applied more and more. Curved girder bridge is a complicated spatial structure, and "bending and torsional coupling" is the most obvious force characteristic. Based on the basic theory of curved bridge and finite element method, based on the Fengsha railway bridge of Beijing metro line 14, the stress characteristics of prestressed concrete curved beam are analyzed in detail, and the influence of curve radius on the mechanical behavior of curved beam is summarized. In view of the common diseases of curved girder bridge in construction and operation, the effects of prestress load and temperature load on curved beam are studied, and the causes of web plate steel bundle side collapse, main beam "climbing and moving" and support detachment are analyzed. Some preventive measures are put forward. The results show that under the action of vertical load outside the plane, even the symmetrical load, the torsional moment in the curved beam will be larger and the corresponding torsional deformation will occur. This kind of torsion causes the internal and external forces of curved beam to be uneven, which mainly shows the stress difference in the inside and outside of the beam and the difference in the reaction force between the inner and outer supports of the double bearing with torsion. With the decrease of radius, the torsional moment of curved beam increases, and the force on both sides of the beam becomes more uneven, and the torsional deformation becomes more severe. Therefore, in the design of curved girder bridge, under the premise of satisfying other requirements, the larger curve radius should be chosen as far as possible. When the curve radius is very small or the tensile force is very large, the radial horizontal distribution force of prestressing force will easily cause the lateral collapse of web steel bundle during construction. For this reason, the prestressed steel bundle can be removed from the outside, the anti-avalanche steel bar is added, and the transverse partition plate is reasonably set up. In order to prevent the occurrence of this kind of disease, the methods of web anti-avalanche checking and so on are carried out. Torsion and temperature load caused by prestress are also the important reasons for "climbing and moving" of curved beam and void of support. Enough deformation of expansion joints and allowable deformation of supports should be reserved in design to ensure the free expansion of curved beams along the tangential direction, and certain limiting measures should be taken at the same time; for the phenomenon of support clearance, it is possible to increase the distance between the supports at the end of the beam, The method of strengthening the torsion resistance of the end beam body is used.
【學位授予單位】：北京交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U445.7;U441
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，本文編號：2280022
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