In this paper, a new type prefabricated partially encased composite beam (PEC beam) using screw arbors instead of stirrups or welded transverse links in ordinary PEC structures to connect the upper and lower steel flange has been proposed. It not only retains the performance advantages of PEC structures, but also greatly enhances the prefabricated degree of structure and simplifies construction process. Twelve beams with and without screw arbors were tested under cyclic loading to study the mechanical behavior of this new type of PEC beams. The major factors considered were shear span ratio (λ = 1.0, 2.0, 3.0 and 4.0), with or without screw arbors and concrete thickness. Test results including failure mode, load–deflection curves (P − Δ curves), characteristic points, ductility and stiffness were introduced and discussed in detail. The test results showed that the failure mode of PEC beams changed from shear failure to bending failure with the increase of shear span ratio, and the asymmetric damage of specimens can be improved by screw arbors. In addition, PEC beams with screw arbors have better ductility and slower stiffness degeneration than those without screw arbors. Potential application value can be seen from this new type of prefabricated PEC beams.

中文翻译：

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预制PEC组合梁循环荷载下力学性能的试验研究。

在本文中，提出了一种新型的预制的部分包裹的复合梁（PEC梁），该螺钉在普通的PEC结构中使用螺钉轴而不是箍筋或焊接的横向连杆来连接上下钢制法兰。它不仅保留了PEC结构的性能优势，而且大大提高了结构的预制程度，简化了施工过程。在循环载荷下测试了十二个带有和不带有螺纹轴的梁，以研究这种新型PEC梁的力学性能。考虑的主要因素是剪切跨度比（λ  = 1.0、2.0、3.0和4.0），带或不带螺杆和混凝土厚度。试验结果包括故障模式，载荷-挠度曲线（P  -  Δ曲线），特征点，延展性和刚度进行了介绍和详细讨论。试验结果表明，随着剪切跨距比的增大，PEC梁的破坏模式从剪切破坏变为弯曲破坏，并且可以通过螺钉芯轴改善标本的不对称损伤。此外，与没有螺杆的PEC梁相比，具有螺杆的PEC梁具有更好的延展性和较慢的刚度退化。从这种新型的预制PEC梁中可以看到潜在的应用价值。