考虑混凝土影响的既有变截面箱梁桥的全局疲劳寿命评估

Global Fatigue Life Evaluation of Reinforced Concrete Box Girder Bridges with Variable Cross-section

基于复杂多轴疲劳理论、损伤积累理论、子模型法及变截面箱梁桥横截面的几何非线性特性,提出了考虑混凝土寿命的变截面钢筋混凝土箱梁桥全局疲劳寿命的评估方法。以一座既有公路变截面钢筋混凝土箱梁桥为工程背景,研究了纵向多车效应和横纵向多车效应两种工况下的桥梁全局疲劳寿命差异。结果表明:全桥疲劳寿命由第三跨跨中节段控制,横纵向多车加载比纵向多车加载的桥梁疲劳总寿命减少了29.4%,腹板混凝土寿命占到腹板寿命3%左右。

Based on the complex multi axis fatigue theory,the damage accumulation theory,sub-model method and the geometric nonlinear characteristics of the cross section of box girder bridge with variable cross-section,the global fatigue life evaluation method considered concrete life for the variable cross-section reinforced concrete box girder bridge was proposed.Taking a reinforced concrete box girder bridge withexisting highway variable cross-section as the engineering background,the difference of the global fatigue life of the bridge under the two conditions of longitudinal multi vehicle effect and transverse longitudinal multi vehicle effect was studied.The results indicate that the fatigue life of the full bridge is controlled by third span middle sgement,and the fatigue life of the bridge with transverse longitudinal multi vehicle loading is 29.4%less than that of the longitudinal multi vehicle,and the web concrete life accounts for about 3%of the web life.