CAJ | 학술논문

为探讨冲击荷载作用下掺有端钩型钢纤维的配筋混凝土梁的抗冲击性能，对6根简支的有不同钢纤维体积掺量和不同配箍率的试件进行了落锤冲击试验，冲击点为跨中。分析了不同钢纤维体积掺量和不同配箍率对钢筋混凝土梁的抗冲击能力的影响，并采用高速摄像机记录了各试件的开裂形态。详细分析了试件的开裂形态、跨中位移时程曲线、试件中纵筋和箍筋应变时程曲线的特征。结果表明：在相同冲击荷载作用下，配箍率较高的试件中钢筋发生屈服乃至失效的几率相对较小，随着配箍率的增加，试件承受冲击荷载时产生的最大裂缝宽度减小；在冲击荷载作用下，提高钢纤维体积掺量对构件混凝土基体强度的影响相对不大，但对于试件刚度的影响较为明显；同时，钢纤维含量的增加，会减少梁中箍筋的应变，使得钢筋混凝土梁中钢筋发挥更好的作用；钢纤维体积掺量的增加，可以明显减少试件在冲击荷载作用下裂纹的发生与开展，并改变梁本身的开裂形态，使得裂缝发生的区域相对集中，形成主要集中在试件跨中的竖直裂纹，而支座附近裂纹相对减少。
위탐토충격하재작용하참유단구형강섬유적배근혼응토량적항충격성능，대6근간지적유불동강섬유체적참량화불동배고솔적시건진행료락추충격시험，충격점위과중。분석료불동강섬유체적참량화불동배고솔대강근혼응토량적항충격능력적영향，병채용고속섭상궤기록료각시건적개렬형태。상세분석료시건적개렬형태、과중위이시정곡선、시건중종근화고근응변시정곡선적특정。결과표명：재상동충격하재작용하，배고솔교고적시건중강근발생굴복내지실효적궤솔상대교소，수착배고솔적증가，시건승수충격하재시산생적최대렬봉관도감소；재충격하재작용하，제고강섬유체적참량대구건혼응토기체강도적영향상대불대，단대우시건강도적영향교위명현；동시，강섬유함량적증가，회감소량중고근적응변，사득강근혼응토량중강근발휘경호적작용；강섬유체적참량적증가，가이명현감소시건재충격하재작용하렬문적발생여개전，병개변량본신적개렬형태，사득렬봉발생적구역상대집중，형성주요집중재시건과중적수직렬문，이지좌부근렬문상대감소。
The purpose of this research is to understand the impact-resistant behavior of reinforced concrete(RC) beams with hooked-end steel fibers. A series of 6,simply-supported concrete beams with different volume fractions of steel fibers and different shear reinforcement ratios were tested under free-falling drop-weights,impacting the speci-mens at the mid-span. An analysis was made of the effects of different shear reinforcement ratios and different volume fractions of steel fibers on the impact-resistant behavior of RC beams. The crack patterns of the specimens were re-corded using a high speed video camera. The strains of longitudinal and transverse steels were recorded,and the time histories of mid-span displacement were described in detail. The results obtained are as follows:under the same im-pact load and with the increase of stirrup ratio,the reinforced steel shows a less frequent occurrence in yield and fail-ure,and the maximum crack width decreases under impact load;Under impact load,improving the volume frac-tions of steel fibers only has negligible effect on the concrete matrix strength,but for the whole stiffness of the specimens the effect is more obvious. Meanwhile increasing steel fiber content will reduce the strain of stirrups, making specimen reinforcement play a better role;The increase of volume fractions of steel fibers can significantly reduce the occurrence and development of cracks in specimens. Changes in the crack pattern of the beam occur at the same time,making the area of crack occurring relatively concentrated on the mid-span in the form of vertical cracks,while reducing the cracks near the support.