Bond Performance of Structural Members of High Strength Lightweight Concrete Reinforced by Frp Rods

1. 目的研究替代钢筋的连续FRP棒与混凝土的粘结性能。材料为规定抗压强度为360kgf/cm^2的高强轻质混凝土和碳、芳纶、玻璃连续纤维棒。为了与普通钢筋混凝土进行比较，还采用了普通混凝土和钢筋进行纵向加固。悬臂式试件共43个，其中轻混凝土29个，普通混凝土14个。它们的尺寸是20厘米宽，35厘米深。通过独立拉出其上下纵向钢筋直径约为13mm，粘接长度为30cm，进行粘接劈裂试验。试验结果参考了6个梁型试件在循环和反对称荷载作用下发生粘结断裂的试验结果。结论通过反复分析，建立了以混凝土和侧筋作用的劈裂强度之和表示的经验公式，并确定了上下筋的关系。其他主要结果如下。混凝土的强度与同类几乎没有关系。在钢筋纵向加固的情况下，纤维侧向加固的强度可以通过将钢壳的值乘以其与钢的杨氏模量的三次方来评估。仅纤维配筋情况下，混凝土强度随纵向配筋形状和刚度的不同而变化，一般刚度越小，强度越小。对于横向配筋的影响，角钢纵筋与中间纵筋的配筋贡献比约为2:1.6，钢纵筋的配筋贡献比为2:1。通过对悬臂梁试验结果的分析，可以预测梁试件的极限强度。

1. ObjectiveObjective of this study is emphasized on bond performance between continuous FRP rods, which are substitute reinforcement for steel bars, and concrete. Used materials were high-strength light-weight concrete of specified compressive strength of 360kgf/cm^2 and carbon, aramid and glass continuous fiber rods. To make a comparison with ordinary RC, normal concrete and steel bars for longitudinal reinforcement were also used.2. ExperimentsTotal of cantilever type specimens was 43, i. e., 29 of light-weight concrete and 14 of normal one. Their size was 20cm wide and 35cm deep. Bond splitting test was carried out by pulling independently out their top and bottom longitudinal reinforcement of diameter of about 13mm with bonding length of 30cm. Test results were referred to those derived from test of 6 beam type specimens, which failed in bond splitting, under cyclic and antisymmetric loading.3. ConclusionEmpirical formulae, in which bond splitting strength was expresed as the sum of those due to concrete and lateral reinforcement, were established by recurrent analysis, by which relationships of top to bottom reinforcement were also determined. Other leading results were as follows. Strengths due to concrete had hardly relation to its kind. In case of steel longitudinal reinforcement strengths due to fiber lateral reinforcement could be evaluated by multiplying values of steel case by ratios of Young's modulus of it to steel to the third power. In case of fiber reinforcement only, strengths due to concrete varied with shape and stiffness of longitudinal reinforcement and generally speaking, the lower stiffness was, the lower strength was. As to effect of lateral reinforcement ratios of contribution of corner longitudinal bars to middle ones were about 2 : 1.6, while they were 2 : 1 in case of steel longnal bars. Ultimate strength of beam specimens could be predicted from analysis of results of cantilever test.