中文摘要：

借鉴复合材料力学的分析方法，建立一种分层剪滞模型，研究了碳纤维片材加固钢筋混凝土梁在四点弯曲载荷作用下的多重开裂破坏，求得了梁纯弯段下部钢筋保护层中的最大裂缝宽度和裂缝密度与施加载荷和碳纤维片材的粘贴层数之间的定量关系，计算结果与现有实验值较吻合．结果表明：施加载荷愈大，裂缝密度和宽度愈大；随着碳纤维片材粘贴层数的增加，裂缝间距明显变小，最大裂缝宽度则基本保持稳定；在碳纤维片材粘贴层数较小的情形下，当施加载荷达到或超过某值时，梁纯弯段下部混凝土保护层将出现饱和裂缝群．

英文摘要：

With the aid of the analytical methods of composite mechanics, a layered shear-lag model is established to investigate the multiple cracking of reinforced concrete （RC） beam reinforced with carbon fiber sheets under four-point bending. The relationships between the crack items and the applied load as well as the number of carbon fiber sheets are then obtained, where the crack items include the crack density and the maximum crack width in the reinforcement cover under the pure bending part of the beam. The calculated results are in good agreement with the existing experimental ones, showing that （1） the crack density and width increase with the applied load; （2） with the increase of the number of carbon fiber sheets, the crack spacing obviously becomes small, while the maximum crack width almost remains constant; and （3） in the case of a small number of carbon fiber sheets, a duster of saturation cracks emerge in the reinforcement cover under the pure bending part of the beam when the applied load reaches or exceeds a certain value.