Application of Fracture Mechanics to Flexural Failure Behavior of Concrete

断裂力学在混凝土弯曲破坏行为中的应用

• 批准号: 03650391
• 负责人: ROKUGO Keitetsu
• 金额: $ 1.22万
• 依托单位: Gifu University, Faculty of Engineering
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03650391/
• 关键词: Concrete; Fracture Mechanics; Flexural Failure; Fracture Energy; Tension Softening; Size Effect; Reinforced Concrete; Steel Fiber Reinforced Concrete; コンクリ-ト; 破壊エネルギ-; 鉄筋コンクリ-ト; 鋼繊維補強コンクリ-ト

Fracture mechanics concepts such as tension softening diagrams are applied to investigate the flexural failure behavior of concrete and reinforced concrete beams. The following topics are dealt with in this study. 1. Effects of specimen size and cross-sectional shape on flexural strength of concrete. 2. Determination of fracture energy and flexural strength by means of bend-off tests. 3. Flexural failure behavior of steel fiber reinforced concrete beams. 4. Flexural failure behavior of lightly reinforced concrete beams.The following results are obtained from experiments and numerical analysis. 1. Results of experiments and analysis indicate that the flexural strength of concrete beams decrease as the specimen depth increases. 2. An equation to estimate the flexural strength of concrete beams with different depths is proposed. 3. It is seen from experiments and analysis that the flexural strength of concrete beams with circular cross-section is larger than that of beams with square cross-section due to the contribution of the tension softening. 4. The effects of steel fiber reinforcement is more remarkable for larger beams. 5. The tension softening properties of concrete are taken into account in equations to estimate the cracking load and yielding load of lightly reinforced concrete beams. 6. It is shown that the deformation on the descending branch of load-displacement curves tends to localize whereas it tends to spread before the peak load.

断裂力学的概念，如张力软化图被用于研究混凝土和钢筋混凝土梁的弯曲破坏行为。本研究涉及以下主题。1. 试件尺寸和截面形状对混凝土抗弯强度的影响。2. 用弯曲试验方法测定断裂能和弯曲强度。3. 钢纤维混凝土梁的受弯破坏行为。4. 轻钢筋混凝土梁的受弯破坏行为。实验和数值分析结果如下：1. 试验和分析结果表明，随着试件深度的增加，混凝土梁的抗弯强度减小。2. 提出了一种估算不同深度混凝土梁抗弯强度的公式。3. 从试验和分析可以看出，圆形截面混凝土梁的抗弯强度由于受拉软化的贡献大于方形截面混凝土梁的抗弯强度。4. 钢纤维加固对大梁的影响更为显著。5. 在计算轻钢筋混凝土梁的开裂荷载和屈服荷载时，考虑了混凝土的受拉软化特性。6. 结果表明，荷载-位移曲线下降分支的变形在峰值荷载前趋于局部化，而在峰值荷载前趋于扩散。

项目成果

六郷恵哲: "鋼繊維補強コンクリートの曲げ強度の寸法依存性" セメント コンクリート論文集. 46. 482-487 (1992)

Keiji Rokugo：“钢纤维混凝土弯曲强度的尺寸依赖性”《水泥混凝土论文》46. 482-487 (1992)。

ROKUGO,K.: "Flexural Failure Behavior of Lightly Reinforced Concrete Beams" Fracture Mechanics of Concrete Structures,FRAMCOS-1,Elsevier Applied Science. 775-781 (1992)

ROKUGO,K.：“轻质钢筋混凝土梁的弯曲破坏行为”混凝土结构断裂力学，FRAMCOS-1，爱思唯尔应用科学。

三橋 博三: "コンクリート構造への破壊力学的の応用" コンクリート工学. 30-6. 5-17 (1992)

Hirozo Mitsuhashi：“断裂力学在混凝土结构中的应用”《混凝土工程》30-6（1992）。

六郷恵哲: "コンクリートの破壊の局所化と強度の寸法依存性" コンクリートライブラリー (土木学会). 69. 96-110 (1991)

Keiji Rokugo：“混凝土中断裂的局部化和强度的尺寸依赖性”混凝土图书馆（日本土木工程师学会）69. 96-110（1991）。

瀬古繁喜: "鉄筋比が小さいRCはりの曲げ破壊性状" コンクリート工学年次論文報告集. 13-2. 255-258 (1991)

Shigeki Seko：“小钢筋比 RC 梁的弯曲破坏特性”混凝土工程年报 13-2（1991）。