【作者】 赵锋军；

【导师】 易伟建；

【作者基本信息】 湖南大学 ， 桥梁与隧道工程， 2012， 博士

【摘要】 大跨径钢箱梁桥面沥青铺装是国际性工程难题与研究热点。缺乏系统的设计、合理的选材、规范的施工与科学的管理是造成国内钢桥面沥青铺装使用寿命短的重要原因，设计模型与计算方法是解决问题的基础之一。本文以大跨径钢箱梁悬索桥的沥青铺装荷载效应计算方法为研究对象，以整桥、节段、局部三层次模型与温度应力计算模型的荷载效应计算方法、铺装疲劳破坏模式、设计指标体系、设计计算方法、铺装设计可靠度等为研究内容，完成如下工作与研究成果：（1）三层次活载效应计算模型的建立与求解以弹性叠层连续梁为基本计算模型，分析推导了悬索桥吊杆对钢箱梁与U肋对钢面板支承刚度的计算公式、钢箱梁截面畸变翘曲刚度计算公式，根据影响线加载的原理、梁的弯曲理论与平截面假定得到铺装活载应力的解析计算方法。本文解析公式的计算结果与常用的有限元方法接近，简化了沥青铺装设计指标计算中繁琐的建模过程。计算结果表明，悬索桥钢箱梁的最不利负弯矩产生一般不发生在跨中，具体位置与弹性支承刚度的分布有关。节段钢箱梁扭转畸变角的变化具有明显局部特征，影响范围约为5～6块横隔板。局部轮载弯矩的影响范围约6个U肋，可不考虑同轴左、右轮载效应的相互影响。（2）温度应力叠层梁模型的建立与求解将钢板——沥青铺装叠层梁模型界面应力函数展开为傅里叶级数，推导得到铺装体系温度应力的计算公式。采用Maxwell模型计算铺装松弛模量，得到考虑材料粘弹性的铺装温度应力计算方法。计算结果表明，沥青铺装表面最大温度应力出现在叠层梁端部，温度应力计算需考虑沥青材料松弛特性，极端低温条件下的温度变化导致沥青铺装产生最不利温度应力。（3）疲劳破坏模式与设计控制指标的确定通过大量钢桥面沥青铺装破损状况调研与直道足尺疲劳试验，得到沥青铺装表面弯拉疲劳与铺装界面弯曲剪应力疲劳两种铺装疲劳模式。分析表明，交通量较轻半幅桥产生较多纵桥向疲劳开裂的机理是节段钢箱梁扭转畸变在沥青铺装表面产生的横桥向弯拉应力。肋间最大正弯矩区域出现纵桥向疲劳开裂则是由于界面剪切破坏后，铺装底部产生的弯拉应力疲劳裂纹向上扩展。横桥向裂缝是活载应力与温度应力最不利组合的结果。铺装结构弯拉应力与界面剪应力可作为设计控制指标且应考虑荷载效应的最不利组合；（4）钢桥面沥青铺装设计方法提出了基于动态设计指标体系的“验算模式”铺装设计方法，综合考虑铺装材料疲劳性能、桥面板承载规律以及行车特征等，推导了典型铺装材料轴载换算公式，采用三层次模型活载应力与温度应力组合的方法，得到横桥向最不利应力为活载应力控制，纵桥向最不利应力为温度应力控制，疲劳设计应以活载应力为主，温度应力为验算指标。对沥青铺装高温稳定性、低温抗裂性、水稳定性等进行了讨论。（5）钢桥面沥青铺装可靠度计算方法采用本文推导的荷载应力计算公式，利用Monte Carlo随机抽样的原理，分析铺装结构应力疲劳可靠度，结果表明，活载应力控制的不利组合应力作为材料设计控制指标，疲劳设计能够满足规范要求的可靠度水平。验算温度应力控制的荷载组合可靠度时，沥青铺装材料强度需考虑温度修正。更多还原

【Abstract】 The steel deck asphalt pavement on large-span steel box beam bridges is adifficult engineering problem and research focus at home and abroad. The importantreasons for short service life of asphalt pavement on steel deck in China are thedefects of systematic design method, reasonable selection of materials, standardizeconstruction and scientific management. The design model and calculation methodare base for solving this problem. In this thesis, the calculation methods of loadaffects in asphalt pavement on long span steel suspension bridge have beenresearched as the objective. The researches include the calculation methods of loadaffects in asphalt pavement system using full-bridge model, section model and localmodel, which is called three hierarchies’ structure model and thermal stress model.The researches also include the fatigue type of asphalt pavement on steel deck, andits design indexes system, design calculation method and fatigue reliability analysis.The research works and new developments are as follows:(1) The three hierarchies’ structure models for live load effects have beenmodeled and solved.Based on elastic laminated continuous beam as the basic model, the formulas ofsupport stiffness of suspender in suspension bridge acting on steel box beam andU-stiffener acting on steel deck have been derived. The formulas of cross-sectionwarping stiffness of steel box beam have been derived too. Based on the theory ofinfluence-line loading, bending theory of beam and plane section assumption, theanalytic calculation methods for live loads stress in asphalt pavement have been got.The calculation results based on analytical formulas in this paper agree with theresults using finite element method, and the tedious modeling process can besimplified in calculation for design index of asphalt pavement. The calculationresults show that the most dangerous sagging moment of steel box girder inlong-span suspension bridges do not occur in midspan. Its position depends on thestiffness distribution of elastic support. The distortion angle being caused bysegment distortion of steel box girders show obvious local characteristic. Theinfluence scope is about five to six times distance between diaphragms. Theinfluence scope of local loads moment is about six times distance betweenU-stiffeners. So the interact of two wheel load on one axle can be ignored.(2) The laminated beam models for thermal stress have been modeled and solved.The stress functions of interface between steel deck and asphalt pavement havebeen expanded by Fourier series. The analytical formulas of thermal stress of asphaltpavement have been derived. The maxwell model has been used in calculation forrelaxation modulus, and the calculation method of pavement thermal stressconsidering viscoelasticity of material has been got. The calculation results showthat the max thermal tensile stress occurs in the end of beam. The calculation ofthermal stress must take the relaxation of asphalt material into consideration. Theconditions of most dangerous thermal stress are extreme low temperature and rangeof temperature change.(3) The asphalt pavement fatigue types and design indexes system have beendetermined.The two fatigue types of asphalt pavement have been got based on lots ofdamage investigation and full-scale fatigue experiment in straight track test. One isbending fatigue in asphalt pavement surface. Another one is shear fatigue ininterface between steel deck and asphalt pavement. The analysis showed that themechanism of longitudinal fatigue crack in pavement, which half bridge crosssection has less traffic volume, is the transverse flexural stress in asphalt pavementsurface caused by segment distortion of steel box girders. The pavement longitudinalfatigue cracks appeared on the region of sagging moment between U-stiffeners iscaused by interface bond destroys. The shear failure will cause the bending tensionstress in bottom of asphalt pavement and the flexure fatigue cracking can expandupward. Load combinations of live load stress and thermal stress cause thetransverse cracking. The flexural stress in pavement and shear stress in interface canbe used as design indexes and the most unfavorable stress combination should beconsidered.(4) The design method of steel deck asphalt pavementThe design method of asphalt pavement, which being called checking mode, hasbeen proposed based on dynamic design indexes system. The axle-load-conversionformulas for typical pavement materials have been derived considering fatigueproperty of pavement material, bearing capacities of steel deck and trafficcharacteristic. Using method of load combination, which including live load stress inthree hierarchies’ models and thermal stress, the results show that the transversestress is controlled by live load effect and the longitudinal stress is controlled bytemperature effect. The fatigue design for pavement should use live load effect as the design index and thermal stress as the checking index. The performances ofasphalt pavement, which including high temperature stability, low temperature crackresistance, water stability and so on, have been analyzed.(5) The computer method for reliability of steel deck asphalt pavementThe reliability of asphalt pavement has been analyzed based on formulas in thisthesis and random sampling principle of Monte Carlo method. The result show that thereliability of fatigue design can satisfy the code requirement using the mostdangerous combination of live load effect and the material strength of asphaltpavement should consider temperature correction when checking the most dangerouscombination of thermal stress.更多还原