Abstract The number of aging bridges in Japan is increasing, and steel-concrete composite slabs are commonly used in replacement work due to their durability and associated savings in construction time. Due to the limited capacities of existing bridge columns, replacement of the old bridge deck with a lightweight alternative is preferable. This study proposes an innovative steel-concrete composite slab with a thickness of 180 mm consisting of lightweight aggregate concrete (LWAC) and rectangular steel pipes (RSPs) as a new type of shear connector. The total weight could be reduced by about 20% from that of steel-concrete composite slabs. To investigate the shear properties of RSP, a push-out test was conducted on three specimens with static loading and five with fatigue loading. The static experimental results showed that the shear capacity of the RSPs could be determined by cracks, which occurred near the weld zone. Two failure patterns, RSP cracks and weld separation, were observed in the different specimens under fatigue loading. The static shear capacity was compared with the calculated results using different C-shaped and L-shaped channel specifications, and a headed stud number equivalent to one RSP was proposed. The S N curve of RSP was compared with that of the headed studs, and the fatigue performance appeared to be better than that of the studs when the shear stress was below 125 MPa. The changing trend in the slip rate and the normalised stiffness of the RSP when the fatigue loading cycles increased were investigated and formulated.

中文翻译：

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钢-混凝土复合板中创新剪力连接件的特性

摘要 日本老化桥梁的数量正在增加，钢-混凝土复合板由于其耐用性和施工时间的节省而常用于更换工作。由于现有桥柱的承载能力有限，最好用轻质替代品替换旧桥面。本研究提出了一种厚度为 180 毫米的创新型钢-混凝土复合板，由轻骨料混凝土 (LWAC) 和矩形钢管 (RSP) 组成，作为一种新型剪力连接件。与钢-混凝土复合板相比，总重量可减少约20%。为了研究 RSP 的剪切性能，对三个带有静载荷的试样和五个带有疲劳载荷的试样进行了推出试验。静态实验结果表明，RSPs 的剪切能力可以由裂纹确定，裂纹发生在焊接区附近。在疲劳载荷下，在不同试样中观察到两种失效模式，RSP 裂纹和焊缝分离。将静态抗剪承载力与使用不同 C 形和 L 形通道规格的计算结果进行比较，并提出了相当于一个 RSP 的有头螺栓数量。将RSP的SN曲线与有头螺柱的SN曲线进行比较，当剪切应力低于125 MPa时，疲劳性能似乎优于螺柱。研究并制定了当疲劳载荷循环增加时 RSP 滑移率和归一化刚度的变化趋势。在疲劳载荷下，在不同试样中观察到两种失效模式，RSP 裂纹和焊缝分离。将静态抗剪承载力与使用不同 C 形和 L 形通道规格的计算结果进行比较，并提出了相当于一个 RSP 的有头螺栓数量。将RSP的SN曲线与有头螺柱的SN曲线进行比较，当剪切应力低于125 MPa时，疲劳性能似乎优于螺柱。研究并制定了当疲劳载荷循环增加时RSP的滑移率和归一化刚度的变化趋势。在疲劳载荷下，在不同试样中观察到两种失效模式，RSP 裂纹和焊缝分离。将静态抗剪承载力与使用不同 C 形和 L 形通道规格的计算结果进行比较，并提出了相当于一个 RSP 的有头螺栓数量。将RSP的SN曲线与有头螺柱的SN曲线进行比较，当剪切应力低于125 MPa时，疲劳性能似乎优于螺柱。研究并制定了当疲劳载荷循环增加时RSP的滑移率和归一化刚度的变化趋势。将静态抗剪承载力与使用不同 C 形和 L 形通道规格的计算结果进行比较，并提出了相当于一个 RSP 的有头螺栓数量。将RSP的SN曲线与有头螺柱的SN曲线进行比较，当剪切应力低于125 MPa时，疲劳性能似乎优于螺柱。研究并制定了当疲劳载荷循环增加时RSP的滑移率和归一化刚度的变化趋势。将静态抗剪承载力与使用不同 C 形和 L 形通道规格的计算结果进行比较，并提出了相当于一个 RSP 的有头螺栓数量。将RSP的SN曲线与有头螺柱的SN曲线进行比较，当剪切应力低于125 MPa时，疲劳性能似乎优于螺柱。研究并制定了当疲劳载荷循环增加时 RSP 滑移率和归一化刚度的变化趋势。