大跨度波形钢腹板连续刚构桥受力特点及剪力键试验研究

发布时间：2018-04-23 14:25

本文选题：波形钢腹板 + 箱梁桥　；参考：《西南交通大学》2015年博士论文

【摘要】：波形钢腹板钢筋混凝土组合箱梁结构具有诸多优势,近些年来在国外得到了较快的发展,国内也有较多研究。国内外对波形钢腹板特性的研究结论主要通过数值分析、模型试验得到；对适用于大跨度波形钢腹板箱梁桥剪力键研究的针对性不强,或与其构造及受力特点不完全相同。以兰州北环小砂沟大桥为工程背景,对大跨度波形钢腹板箱梁桥的主要特性进行了理论研究,针对大跨度波形钢腹板箱梁桥剪力键的构造特点和受力特点,完成了13组共39个1:1比例的剪力键模型试验,对大跨度波形钢腹板的剪力键特性进行了研究,主要内容如下：1.通过波形钢腹板纵向刚度相等原理,推导了波形钢腹板的纵向等效厚度及等效弹性模量的计算方法,从理论上证明波形钢腹板所承担弯矩占全截面总弯矩的比例很小,可以忽略,在计算波形钢腹板箱梁的抗弯承载能力时,可仅考虑顶底板的作用,而不考虑波形钢腹板的作用；从理论上研究波形钢腹板的抗剪性能,证明钢腹板中的剪应力在钢腹板高度方向上基本相等,钢腹板基本为纯剪切受力状态；得出钢腹板所承担的剪力占总剪力比例规律的计算公式；在波形钢腹板箱梁结构中,顶底板要承受相当一部分的截面剪力,波形钢腹板所承担的剪力占总截面剪力的比例不超过85%。2.从理论上研究变高度波形钢腹板箱梁中梁高变化对波形钢腹板中剪应力的影响,并得出相应计算公式。当截面负弯矩增大且截面高度增加时,底板中的压力可抵消一部分截面剪力,反之,当截面负弯矩增大且截面高度降低时,底板中的压力将增加腹板中的剪力。3.研究滑移对波形钢腹板箱梁承载能力和挠度的影响,研究滑移产生附加弯矩和附加挠度的计算方法。4.将PBL剪力键的承载能力分为弹性承载能力和极限承载能力,对弹性承载能力附加滑移量约束后,成为具有实际工程意义的设计承载能力。通过剪力键模型试验,得出适用于大跨度波形钢腹板箱梁桥剪力键的主要特性：(1)PBL剪力键具有良好的延性性能,在破坏前均有明显的屈服过程,滑移有较为明显的增长；具有较高的设计承载能力和极限承载能力,其极限承载能力明显大于设计承载能力,极限承载能力与设计承载能力之比大于2.0。(2)钢板开孔直径越大,PBL剪力键的设计承载能力和极限承载能力也越大；当开孔直径大到一定程度时,钢板的变形会成为滑移变形的主要因素,PBL剪力键的钢板成为控制因素,达到极限承载能力时,剪力键的破坏由钢板的破坏引起。(3)贯穿钢筋直径对PBL剪力键设计承载能力的影响很小；贯穿钢筋直径对PBL剪力键极限承载能力的影响较大,钢筋直径越大,极限承载能力越大。(4)钢板厚度对PBL剪力键的设计承载能力和极限承载能力均有较大影响,钢板厚度越大,其设计承载能力和极限承载能力均越大。(5)预拉应力能够减小PBL剪力键的设计承载能力和极限承载能力,尤其当横向拉应力达到混凝土抗拉强度时,其设计承载能力和极限承载能力的减小更为明显；预压应力能够提高PBL剪力键的设计承载能力和极限承载能力；预应力的影响在设计承载能力公式与极限承载能力公式计算中可单独考虑。(6)钢板开梯形孔的PBL剪力键由于开孔面积较大,其破坏形态、承载能力特点与开大直径圆孔PBL键的破坏形态、承载能力特点相似。(7)若在角钢连接键中没有配置垂直于受力方向的受力钢筋,则剪力键的延性性能较差,在破坏前屈服现象不明显,破坏前的滑移量为2mm左右,属于脆性破坏；在不配置钢筋时,单个角钢剪力连接件的极限承载能力代表值为1700kN。(8)将剪力键极限承载能力与设计承载能力之比作为剪力键的另一个延性指标Ⅱ,剪力键极限承载能力所对应的滑移量与0.2mm之比作为延性指标Ⅰ,延性指标Ⅱ较延性指标Ⅰ数值较小,更加稳定。(9)根据试验资料拟合PBL剪力键设计承载能力和极限承载能力的计算公式,该公式仅适用于波形钢腹板箱梁腹板与顶底板混凝土之间连接的PBL剪力键,该类剪力键只有一排开孔,该公式实在PBL剪力键的钢板高度为20cm,孔径60～90mm之间,贯穿钢筋直径16～25mm之间,钢板厚度20～24mm之间得出的,当这些参数超出这个范围太多时,该计算公式不再适用。(10)对模型试件进行有限元分析,将计算结果与试验结果对比分析表明,试件0.2mm滑移对应荷载的计算值试验值差异除配置预拉应力的试件外均较小,差异最大值为22.1%,试件极限承载能力的计算值与试验值除两个试件外均不大,差异最大值为22.6%。5.研究了兰州北环小砂沟大桥的构造特点和受力特性,证明小砂沟大桥受力合理。
[Abstract]:The reinforced concrete composite box girder with corrugated steel web has many advantages, which has been developed rapidly abroad in recent years, and there are many studies in China. The research conclusions on the characteristics of corrugated steel web at home and abroad are mainly through numerical analysis, model test, and the needles applied to the shear bond of large span corrugated steel web box girder bridge. The main characteristics of the large span corrugated steel web box girder bridge are theoretically studied in the background of the Lanzhou North Ring small shitge bridge. 13 groups of 39 1:1 shear forces are completed in view of the structural characteristics and the stress characteristics of the shear bond of the large span corrugated steel web box girder bridge. The shear bond characteristics of the large span corrugated steel webs are studied by the key model test. The main contents are as follows: 1. the calculation method of the longitudinal equivalent thickness and the equivalent elastic modulus of the corrugated steel webs is derived by the principle of the equal longitudinal stiffness of the corrugated steel webs. It is proved theoretically that the bending moment of the corrugated steel web accounts for the total bending moment of the full section. The proportion of the corrugated steel web can be neglected. In calculating the flexural capacity of the corrugated steel web box girder, only the action of the top and bottom can be considered, but the function of the corrugated steel web is not considered. The shear behavior of the corrugated steel web is studied theoretically. It is proved that the shear stress in the steel web is basically equal to the height direction of the steel web, and the steel web is basically pure shear. The shear stress state of the steel web is calculated. In the box girder structure of corrugated steel web, the top and bottom should bear a considerable section of shear force, and the proportion of the shear force of the corrugated steel web is not more than 85%.2.. The influence of the high change of the middle beam on the shear stress in the corrugated steel webs and the corresponding formula are obtained. When the negative bending moment of the section increases and the height of the section increases, the pressure in the floor can offset a part of the shear force. On the contrary, when the negative bending moment increases and the height of the section is reduced, the pressure in the bottom plate will increase the shear.3. of the web and study slip. The influence of the load-bearing capacity and deflection of corrugated steel web box girder, the calculation method of additional bending moment and additional deflection produced by slip.4. divides the bearing capacity of PBL shear bond into elastic bearing capacity and ultimate bearing capacity. After constraint of additional slip quantity of elastic bearing capacity, it becomes a design bearing capacity with practical engineering significance. The shear bond model test shows the main characteristics of the shear bond for the large span corrugated steel web box girder bridge: (1) the PBL shear bond has good ductility performance. It has obvious yield process before the failure, and the slip has a more obvious increase. It has high design bearing capacity and ultimate bearing capacity, and its ultimate bearing capacity is obvious. In the design bearing capacity, the ratio of ultimate bearing capacity to design bearing capacity is greater than that of 2.0. (2), the larger the diameter of the steel plate is, the greater the design bearing capacity and ultimate bearing capacity of the PBL shear bond. When the diameter of the opening is large to a certain extent, the deformation of the steel plate will be the main factor of the slip deformation, and the steel plate of the PBL shear bond becomes the control factor. When the ultimate bearing capacity is reached, the failure of the shear bond is caused by the failure of the steel plate. (3) the influence of the diameter of the reinforcing bar on the design bearing capacity of the PBL shear bond is very small; the diameter of the steel bar has great influence on the ultimate bearing capacity of the PBL shear bond, the larger the diameter of the steel bar, the greater the ultimate bearing capacity. (4) the design of the thickness of the steel plate to the PBL shear bond. The load capacity and ultimate bearing capacity have great influence, the greater the thickness of the steel plate, the greater the design bearing capacity and ultimate bearing capacity. (5) the pretension stress can reduce the design bearing capacity and ultimate bearing capacity of the PBL shear bond, especially when the transverse tensile stress reaches the tensile strength of concrete, its design bearing capacity and ultimate bearing capacity It is more obvious that the preloading stress can improve the design bearing capacity and ultimate bearing capacity of the PBL shear bond. The influence of prestress can be considered in the calculation of the formula of design bearing capacity and the formula of ultimate bearing capacity. (6) the PBL shear bond of the trapezoidal hole of the steel plate is larger, its failure mode and the bearing capacity characteristics of the shear stress key of the trapezoidal hole of the steel plate The bearing capacity characteristics are similar to the PBL key of opening large diameter circular holes. (7) if there is no force reinforcing bar perpendicular to the direction of force in the connection key of the angle steel, the ductility of the shear bond is poor, the yield phenomenon is not obvious before the failure, the slip amount before the failure is 2mm left right, which belongs to the brittle failure; the single angle is not used when the steel bar is not configured. The representative value of the ultimate bearing capacity of the steel shear connector is 1700kN. (8). The ratio of the ultimate bearing capacity to the design bearing capacity is another ductility index of the shear bond. The ratio of the slip quantity to the 0.2mm is the ductility index of the shear bond ultimate bearing capacity. The ductility index II is smaller than the ductility index I, and the value of the ductility index is smaller. (9) (9) according to the experimental data fitting the calculation formula of the design bearing capacity and ultimate bearing capacity of the shear bond, this formula is only applicable to the PBL shear bond which is connected between the web of corrugated steel web box girder web and the top and bottom concrete. This kind of shear bond has only one opening hole, and the formula is real at the height of the steel plate of the PBL shear bond, and the diameter is 60 to 90mm. Between 16 and 25mm of steel diameter, the thickness of steel plate is between 20 and 24mm. When these parameters exceed this range, the formula is no longer applicable. (10) the finite element analysis of the model specimen is carried out. The comparison and analysis of the calculated results with the test results show that the difference of the test values of the 0.2mm slip corresponding to the load is different except for the difference in the test values of the calculated values of the specimens. The specimen with pre tension stress is smaller and the maximum difference is 22.1%. The calculated value of the ultimate bearing capacity of the specimen and the test value are not large except two test pieces. The difference is 22.6%.5. to study the structural characteristics and stress characteristics of the Lanzhou North Ring small sand ditch bridge, which proves that the force of the small sand ditch bridge is reasonable.

【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U441;U448.23

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