Strength of Folded Plate Structures with Shallow Angle and Its Realization for Practical Use

对折腹板梁进行了线性屈曲分析，结果表明，当折叠角为15度进行弯曲，5度进行压缩时，屈曲强度得到了合理的提高。采用丙烯材料的试验研究也证实了这一点，并观察到这些试件即使在屈曲后加载阶段也表现出稳定的性能。对该折叠腹板梁进行了受弯极限强度分析。在折角大于10度的情况下，板梁的承载能力得到了提高，当折板的高宽比和高厚比变化时，折板的极限强度达到稳定状态，强度没有突变；考虑后屈曲性能的板梁采用15度折板时，可以忽略板梁的纵向加劲肋。设计建议可以用LIM…的形式来描述与结构钢屈服应力水平相对应的深厚比。折叠板的抗压强度设计是在保持折叠角大于5度的情况下，按折线间的子板设计方法进行的。但是，为了确定折叠板的强度性能，还需要进行更多的试验研究，并详细介绍折叠板的设计步骤。最后，总结了折叠板制作中的技术问题。由于在实际制造中很难获得折叠角的精度，所以在实际制造中必须设置折叠角的允许范围。有必要将面板折叠成较小的角度，以避免折叠角度的弹回。因此，允许的曲率范围应根据板的厚度、钢材的类型和折叠角度的大小来设置。此外，还必须研究由板的折叠引起的板弯曲和面内构件的残余应力的影响。较少

As a result of linear buckling analysis for the plate girder with folded web, it is found that the buckling strength is reasonably enhanced when the folded angle of 15 degrees is employed for bending, 5 degrees for compression. These are also confirmed by the experimental studies using the acryl material, and it is observed that these specimens show the stable behavior even for the post-buckling loading stage.The ultimate strength analysis is carried out for this folded web girder under bending. The increase of load carrying capacity is confirmed in the case of more than 10 degrees of folded angle, and the ultimate strength is also obtained for variable aspect ratio and depth-thickness ratio of folded web panel, which turns out to be stable state with no abrupt reduction of strength.The longitudinal stiffener of plate girder can be omitted, when the folded web of 15 degrees is employed considering the post-buckling behavior. The design recommendation can be described by the form of lim … More itation of depth-thickness ratio corresponding to the yield stress level of structural steels. The compressive strength design of folded plate is achieved by the present design method for sub-panels between the folded lines when more than 5 degrees of folded angle is maintained. However, it is necessary to conduct more experimental studies using the actual steel material not acryl to confirm the strength property and to present the design procedure in detail.Finally, the technical problems to fabricate the folded plate are summarized. Since the precision of the folded angle is hardly obtained in the actual fabrication, the allowable range of folded angle must be set in the actual fabrication. Is is necessary to fold the panel in the smaller angle to avoid the spring back of folded angle. Therefore, the range of allowable curvature should be set by considering the thickness of plate, type of steel materials and magnitude of folded angle. Moreover, the influence of residual stresses of plate bending and in-plane components induced by the fold of plate must be investigated. Less