中文摘要：

CRTSⅡ型板式无砟轨道结构作为一种纵连板式轨道结构，通常采用6根精轧螺纹钢筋实现轨道板的纵向连接；但因外部荷载作用易造成宽接缝新老混凝土连接处发生开裂，轨道板内部纵连钢筋应力重新分布，有可能会威胁到钢筋的正常工作。基于有限单元法，运用单元生死技术，建立不同宽接缝开裂状态（完全开裂或未开裂）下舍预应力钢筋的桥上CRTSⅡ型板式轨道结构计算模型，研究不同外部荷载作用对纵连钢筋受力性能的影响。结果表明：宽接缝开裂会导致宽接缝位置处钢筋应力的突变；整体温降对钢筋应力的影响最大，降温幅值过大甚至会导致钢筋屈服破坏；正温度梯度对钢筋应力影响较大，会导致宽接缝开裂处钢筋应力的大幅降低；而负温度梯度和列车荷载作用下，宽接缝处钢筋应力变化均不明显。

英文摘要：

CRTS-Ⅱ slab ballastless track belongs to longitudinally continuous slab-type track structure, and the slabs are usually connected by 6 finish-rolled thread reinforcing bars. However, under the action of external loads, the interface between new and old concrete of wide juncture tends to crack. Subsequently, the cracking will cause stress redistribution of the slab＇s longitudinally continuous reinforcing bars, posing a threat to the normal work of the reinforcing bars. Based on finite element method and using element birth-death technology, the paper established a calculation model of CRTS-Ⅱ slab ballastless track on bridge containing prestressed reinforcing bars under the different crack conditions （complete cracking or non-cracking） at the wide juncture, and then researched the influence on the longitudinally continuous bar＇s mechanical property caused by different external loads. The research results show that： （a） The cracking at the wide juncture would cause abrupt stress changing of reinforcing bars. （b） Structure＇s overall temperature drop has greatest influence on the stress state of reinforcing bars, and if the magnitude of temperature drop is too large, the yield failure will even occur in the reinforcing bars. （c） Positive temperature gradient has greater influence on the stress of reinforcing bars, causing considerable stress decreasing of the reinforcing bars at the cracked location of the wide juncture. （d） Under the actions of negative temperature gradient and train load, there is no significant stress changing of reinforcing bars at the wide juncture.