【作者】 张鹏；

【导师】 张清华；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2018， 硕士

【摘要】 正交异性钢桥面由于具有良好的受力性能、较轻的自重而在国内外桥梁工程中得到广泛应用,但其在局部轮载的反复作用下易发生疲劳开裂和铺装层损坏。考虑到超高性能混凝土(UHPC)具有强度高、耐久性好等突出优点,鉴于此,将原钢—混组合桥面板混凝土层置换为UHPC结构层,提出了新型大纵肋正交异性钢—UHPC组合桥面板(简称:高性能组合桥面板),以期解决正交异性钢桥面板所面临的两大问题。为了保证钢桥面板与UHPC结构层之间的协同工作,通常采用短栓钉连接件来实现二者有效连接。与常规钢—混凝土组合结构中的栓钉剪力连接件相比,高性能组合桥面板UHPC结构层中的栓钉较短,剪力钉的长径比不满足钢结构设计规范要求,另一方面结构层的性能对剪力钉的受力状态也有显著影响。本文通过深入分析组合桥面结构中短栓钉受力机理,引入短栓钉延性金属损伤本构及UHPC材料塑性损伤本构,对短栓钉静力及疲劳性能开展相关研究,主要内容和结论如下:(1)在深入分析高性能组合桥面板UHPC结构层中短栓钉受力机理的基础上,将UHPC结构层等效为支承刚度较大的分布线性弹簧系统,推导了短栓钉剪切刚度的解析计算式,提出了采用三折线分段模型表征短栓钉荷载—滑移曲线。(2)基于显式动态求解技术对短栓钉静力推出试验数值分析模型进行了拟静力分析,模型中引入了短栓钉的延性金属损伤本构和UHPC的塑性损伤本构,得到了短栓钉荷载—滑移关系全过程曲线,研究了UHPC结构层与短栓钉的损伤演化规律。(3)引入Broown-Miller多轴疲劳评估准则,对短栓钉的抗剪疲劳性能进行了评估,并与试验结果进行对比,验证了Broown-Miller多轴疲劳评估准则的适用性。在此基础上分析了循环荷载作用下UHPC结构层与短栓钉的损伤演化规律,讨论了应力比及短栓钉直径对短栓钉抗剪疲劳性能的影响。结果表明:应力比对高性能组合桥面板中短栓钉疲劳性能影响显著。随着应力比增大,短栓钉的疲劳寿命值亦增加,且增幅较大;增大短栓钉直径对短栓钉的疲劳性能有改善作用,但改善效果并不显著。更多还原

【Abstract】 Orthotropic steel bridge decks are widely used in domestic and overseas bridge projects because of their good mechanical properties and lighter weight.However,it is prone to fatigue cracking and pavement damage under repeated loading of partial wheel load.Considering the outstanding advantages of ultra high performance concrete(UHPC),such as high strength and good durability,etc,on account of this,the original steel-concrete composite bridge deck concrete layer is replaced by the UHPC structure layer.An innovation composite bridge deck composed of orthotropic steel deck with large longitudinal throughs and UHPC layer(abbreviation: high-performance composite bridge deck)is proposed to solve the two major problems faced by steel bridge panels.In order to ensure the cooperation between the steel bridge deck and the UHPC structural layer,short-headed studs are usually used to achieve effective connection between the two.Compared with the stud-type shear connectors in the conventional steel-concrete composite structure,the stud in the UHPC structural layer of the high-performance composite bridge deck is shorter,and the length-to-diameter ratio of the shear nails don’t meet the requirements of the steel structure design specification.On the other hand,the performance of the structural layer also has a significant effect on the stress state of the shear pin.In this paper,through the in-depth analysis of the mechanism of short studs in combined deck structures,the introduction of short studs and UHPC material damage constitution,and the static and fatigue properties of short studs are studied.The main contents and conclusions are as follows:On the basis of analyzing the force mechanism of short studs in the UHPC structure layer of high performance composite bridge deck,the UHPC structure is equivalent to a linear spring system with large supporting stiffness,and the calculation formula for the shear stiffness of short-headed stud elastic phase is introduced,this paper further put forward the three line model to describe the load slip curve of short-headed stud.Based on the explicit dynamic solution technique,the pseudo static analysis of the short stud static test numerical analysis model was carried out.The ductile damage constitutive model of short stud and the plastic damage constitutive model of UHPC were introduced in the model,The whole process curve of the load-slip relationship of short studs was obtained,and the damage evolution of UHPC structural layers and short studs was studied.The Broown-Miller multi axis fatigue evaluation criterion was introduced to evaluate the shear fatigue performance of short studs,and compared with the test results,the applicability of the Broown-Miller multiaxial fatigue evaluation criterion was verified.The damage evolution of UHPC layer and short stud under cyclic loading is further analyzed,and the effect of stress ratio and short stud diameter on the shear fatigue performance of short studs is discussed.The results show that the stress ratio has a great influence on the fatigue performance of short studs in the high performance composite bridge panel.With the increase of stress ratio,short fatigue life of the studs value also increased,and the increase is larger.Increase the fatigue performance of short stud diameter of short studs had improved,but the effect is not significant.更多还原