拱形蜂窝梁承载能力设计方法研究

发布时间：2018-04-30 12:31

本文选题：圆弧拱形蜂窝梁 + 平面外稳定　；参考：《西安工业大学》2017年硕士论文

【摘要】：拱形蜂窝梁同时具有实腹拱和腹板开洞直梁的优点,拱形蜂窝梁可以实现大跨度的稳定承载体系,节约钢材,其孔洞便于敷设管道和电线,并且造型充满动感,其应用越来越为广泛。但是,拱形蜂窝梁在没有侧向支撑或者侧向支撑不足时,将在发生面内失稳之前发生面外失稳。目前,在实际工程中,大多靠经验来布置侧向支撑,且在学术领域,对蜂窝拱面外失稳问题、特别是侧向支撑对其承载力影响的研究较少。本文将分别对无侧向支撑和有侧向约束时的圆弧拱形蜂窝梁进行平面外稳定性能的研究。设计4根蜂窝拱构件进行静力加载试验,同时建立有限元模型进行仿真模拟,并将两者结果进行对比。通过对比,发现两者结果接近,从而验证了有限元模型的建立方法是正确的。对无侧向支撑的圆弧拱形蜂窝梁进行平面外弹性屈曲的研究。通过有限元模拟,获得三种荷载作用下的屈曲荷载,结合正交试验法中的极差分析,找出目标因素对拱形蜂窝梁屈曲荷载的影响规律及影响程度的先后顺序,进而给出不同荷载作用下各因素的最优组合。结果表明,影响其平面外弹性屈曲的因素顺序为:矢跨比腹板高厚比孔高比。承受相同荷载作用的拱形蜂窝梁,无铰拱的屈曲荷载比两铰拱的屈曲荷载大,且三种因素对其影响的程度越明显。研究有侧向约束时拱形蜂窝梁的平面外弹性屈曲荷载。首先对只有拱顶单个支撑的蜂窝拱进行屈曲分析,研究侧向支撑点截面位置、侧向支撑刚度、矢跨比对屈曲荷载的影响规律,结果表明,侧向支撑应布置在上翼缘最为合理,并给出了单个拱顶支撑时的临界刚度。然后对布置多个等距侧向支撑、承受拱顶集中荷载时的蜂窝拱进行研究,得到结论:蜂窝拱的屈曲荷载随侧向支撑数量的增多(即侧向支撑间距的减小)而增大。且侧向支撑距离为拱的跨度的1/10时,侧向支撑的临界刚度为最大。随着矢跨比的增大,等距布置侧向支撑的临界刚度逐渐减小,这说明,承受拱顶集中荷载的两铰拱,其矢跨比越大,侧向支撑就越有效。结合《拱型钢结构技术规程》中给出的全跨水平均布荷载作用下的双轴对称工字形等截面圆弧两铰拱不再考虑面外失稳时的临界公式,考虑腹板开圆孔的影响,将拱平面内的几何长细比换算为正则化长细比,给出相同情况下腹板开圆孔后的拱不再考虑面外稳定时的临界公式。
[Abstract]:The arch honeycomb beam has the advantages of both the solid web arch and the straight beam with web opening. The arch honeycomb beam can realize the stable bearing system of large span, save steel, facilitate the laying of pipes and wires, and the shape is full of motion. Its application is more and more extensive. However, when there is no lateral support or insufficient lateral bracing, the out-of-plane instability of arch honeycomb beam will occur before in-plane instability occurs. At present, in practical engineering, most of the lateral braces are arranged by experience, and in the academic field, there is little research on the out-of-plane instability of honeycomb arch, especially the influence of lateral bracing on its bearing capacity. In this paper, the out-of-plane stability of circular arched honeycomb beams without lateral support and with lateral constraints is studied respectively. Four honeycomb arch members were designed to carry out static loading test. At the same time, the finite element model was established for simulation, and the two results were compared. By comparison, it is found that the two results are close, which verifies the establishment of the finite element model is correct. The elastic buckling of arc-arched honeycomb beams without lateral support is studied. Through the finite element simulation, the buckling loads under three kinds of loads are obtained. Combining with the range analysis in the orthogonal test method, the influence law and the order of influence degree of the target factors on the buckling loads of the arch honeycomb beams are found out. Furthermore, the optimal combination of various factors under different loads is given. The results show that the order of the factors affecting the out-of-plane elastic buckling is: the rise-span ratio, the ratio of the height to the thickness of the web, the ratio of the hole to the height. The buckling load of arched honeycomb beams subjected to the same load is larger than that of two-hinged arch, and the effect of three factors is more obvious. The external elastic buckling loads of arched honeycomb beams with lateral constraints are studied. First of all, the buckling analysis of honeycomb arch with single bracing with arch roof is carried out to study the influence of lateral support point section position, lateral support stiffness and sagittal span ratio on buckling load. The results show that lateral bracing should be arranged on the upper flange most reasonably. The critical stiffness of single arch support is given. Then, the paper studies the honeycomb arch with multiple isometric lateral braces, which are subjected to concentrated load on the top of the arch. It is concluded that the buckling load of the honeycomb arch increases with the increase of the number of lateral braces (that is, the decrease of lateral bracing spacing). When the lateral support distance is 1 / 10 of the span of the arch, the critical stiffness of the lateral bracing is the largest. With the increase of the rise-span ratio, the critical stiffness of the lateral bracing with isometric arrangement decreases gradually, which shows that the more the rise-span ratio of the arch is, the more effective the lateral bracing is. Combined with the double axisymmetric I-shaped circular arc two-hinged arch given in the Technical Specification for Arch Steel structures under horizontal uniform load with full span, the critical formula for out-of-plane instability is no longer considered, and the influence of web opening is considered. The geometric slenderness ratio in the arch plane is converted to regularized slenderness ratio, and the critical formula for the arch after the web opening is given under the same condition is not considered when the external stability is not considered.
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU391

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