无支撑钢板-砖墙组合梁受弯试验研究

Experimental Study on Normal Section's Bending Resistance of Unsupported Steel Plate-masonry Composite Beams

本文提出的无支撑钢板-砖砌体组合梁,特别适用于既有砌体结构"墙改梁"的快捷绿色施工,不需要支撑即可实现结构托换。为了研究受力性能,通过对六根试件梁进行静载试验,研究其破坏过程与形态、承载力、截面的应变分布以及变形等,并考虑了界面填充材料和螺栓间距的影响。研究结果表明,组合梁的破坏始于钢板的局部压曲失稳;在粘结材料的选择上,结构胶要优于高强灌浆料,在粉刷层材料的选择上,高延性混凝土要优于普通的水泥砂浆;整体性的螺栓加密对于组合梁承载力贡献不大;底部间隔布置缀板能够增强组合梁的整体性,但易导致侧向钢板底部的受力不均匀,形成应力集中;钢板的应变分布沿截面高度,除在底部一小段会受到缀板的影响,其它部分在屈曲之前基本符合平截面假定;"结构胶+高延性混凝土"能够有效提高组合梁的极限承载力,但对塑性变形能力贡献不大。

The proposed unsupported steel plate-masonry composite beam is very suitable for the quick and green construction of the existing masonry structure, which turn a wall into a beam. In order to understand the mechanical properties of this structure, six composed beams under static loads were tested to study the destruction process and mode, carrying capacity, the strain distribution in critical cross-sections,deformation and so on of the composite beams, which considered the influence of the interface filler material and bolt spacing. The results showed that the destruction of the composite beams started with local buckling of the steel plate; the epoxy adhesive is superior to the high-strength grout in the choice of adhesive material, and high ductile concrete is superior to the ordinary cement mortar in the choice of paint layer material; it has little contribution to improve the ultimate bearing capacity of composite beams by reducing bolt spacing overall; the spaced battens at the bottom can enhance the integrity of the composite beams,but it can easily lead to uneven force of the plate in the bottom of the sides and form stress concentration;in addition to the short pieces of the steel on the lower part will be affected by the battens, the other parts’strain distribution along the section height are in line with plane assumption before the plate buckling; epoxy adhesive and high ductile concrete can effectively improve the ultimate bearing capacity of the composite beams, but it has little contribution to enhance t he plastic deformation of the composite beams.