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

1.本文的研究目的是研究连续FRP筋与混凝土之间的粘结性能。使用的材料是规定抗压强度为360 kgf/cm ^2的高强度轻质混凝土，以及碳、芳纶和玻璃连续纤维棒。为了与普通钢筋混凝土进行比较，还采用了普通混凝土和纵向钢筋.试验悬臂梁式试件共43个，即：例如，轻质混凝土29个，普通混凝土14个。它们的尺寸是20厘米宽，35厘米深。粘结劈裂试验采用直径约13 mm的上下纵向钢筋分别单独拔出，粘结长度为30 cm。试验结果参考了6个在循环荷载和反对称荷载作用下发生粘结劈裂破坏的梁型试件的试验结果.结论通过回归分析，建立了粘结劈裂强度为混凝土劈裂强度和侧筋劈裂强度之和的经验公式，并确定了顶筋与底筋的关系。其他主要结果如下。混凝土的强度与其种类几乎没有关系。在钢纵向钢筋的情况下，由于纤维横向钢筋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的比率来评估。在仅纤维增强的情况下，由于混凝土的强度随纵向钢筋的形状和刚度而变化，一般而言，刚度越低，强度越低。在侧筋效应方面，角部纵筋与中部纵筋的贡献比约为2：1.6，而钢纵筋的贡献比约为2：1。通过悬臂梁试验结果的分析，可以预测梁的极限承载力。

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.