Design method of lap splice in reinforced concrete structure

钢筋混凝土结构搭接接头设计方法

• 批准号: 10450203
• 负责人: ICHINOSE Toshikatsu
• 金额: $ 6.46万
• 依托单位: Nagoya Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10450203/
• 关键词: Reinforced concrete; scale effect; rib shape; bond strength; cover thickness; splice; fracture mechanics; stirrups; 強度算定式; 鉄筋径; 全数継手; 異形鉄筋; 付着破壊; 剛体バネモデル; ひび割れ; エポキシ樹脂; ブラックライト; CTスキャン

There is a current interest in using large bars for reinforcing in seismically resistant structures to both reduce congestion and maintain clear spacing between them. While a larger amount of experimental and analytical works have been carried out to study the effects of scale on the shear strength and flexural strength of reinforced concrete, relatively less attention has been devoted to the effects of scale on the bond strength of reinforcement including the effects of scale on tension lap splice strength. This issue has become important for the seismic resistant design of lap splices because the use of small diameter bars leads to congestion and splitting bond failure under strong earthquake loadings.This work is to investigate the effects of scale, rib-shape and lateral reinforcement on bond strength between deformed bar and concrete using pullout and lap splice tests. The specimen parameters are three kinds of bar diameter, two kinds of rib shape, cover thickness, and with/without stirrups. From experimental results, the following conclusions are obtained: 1) pullout specimens with smallest cover thickness showed the largest scale-effect; 2) larger confinement by either cover concrete or stirrups resulted in smaller scale-effect; and 3) scale-effect is attributable to brittle splitting crack around deformed bars and not to local crushing of concrete in front of ribs. Finite element analyzes are also conducted considering the fracture mechanics theory. Based on the experimental and analytical results, design equations are proposed for lap splice. The equations yield large scale-effect for splice with small cover and short splice length where brittle behavior is expected. On the other hand, the equations yield small scale-effect for bars with lower rib height and many stirrups where ductile behavior is expected. The proposed equations agree with the existing experimental results.

目前的兴趣是在抗震结构中使用大钢筋进行加固，以减少拥挤并保持它们之间的清晰间隔。虽然已经进行了大量的试验和分析工作来研究规模对钢筋混凝土的抗剪强度和抗弯强度的影响，但相对较少关注规模对钢筋粘结强度的影响，包括规模对拉伸搭接接头强度的影响。本文通过拉拔试验和搭接试验，研究了钢筋尺寸、肋形和横向配筋对钢筋与混凝土粘结强度的影响。试件参数为三种钢筋直径、两种肋形、保护层厚度、有无箍筋。试验结果表明：1）保护层厚度最小的拉拔试件具有最大的尺度效应; 2）保护层混凝土或箍筋的约束作用越大，尺度效应越小; 3）尺度效应的产生是由于变形钢筋周围的脆性劈裂，而不是由于肋前混凝土的局部压碎。并结合断裂力学理论进行了有限元分析。根据试验和分析结果，提出了搭接接头的设计公式。方程产生大规模的拼接与小覆盖和短拼接长度的脆性行为的预期效果。另一方面，对于具有较低肋高和许多箍筋的钢筋，方程产生较小的尺度效应，其中预期具有延性行为。所提出的方程与已有的实验结果一致。

项目成果

井上 芳樹: "異形鉄筋の付着割裂強度における寸法効果"コンクリート工学年次論文報告集. 23巻3. 841-846 (2001)

Yoshiki Inoue：“变形钢筋粘结劈裂强度的尺寸效应”，混凝土工程年报，第 23 卷，3. 841-846 (2001)。

W.Lin: "The Effects of Scale, Cover Thickness and Rib Angle on the Bond Strength of Reinforcing Bars in Concrete"First International Conference on Advances in Structural Engineering and Mechanics. 1191-1196 (1999)

W.Lin：“规模、保护层厚度和肋角对混凝土中钢筋粘结强度的影响”第一届结构工程和力学进展国际会议。

W. Lin: "Experimental Research on the Effect of Rib Shape and Bar Diameter on Bond Strength"コンクリート工学年次論文報告集. 21・3. 289-294 (1999)

W. Lin：“筋形状和钢筋直径对粘结强度影响的实验研究”混凝土工程年报21・3（1999）。

Toshikatsu Ichinose: "Effect of Rib Shape and Splice Length on the Strength of Lap Splices without Stirrups"Fracture Mechanics of Concrete Structures. vol.2. 1301-1310 (1998)

Toshikatsu Ichinose：“肋形状和拼接长度对无箍筋搭接拼接强度的影响”混凝土结构的断裂力学。

W.Lin: "Experimental Research on the Effect of Rib Shape and Bar Diameter on Bond Strength"Proceedings of the Japan Concrete Institute. Vol. 21, No. 3. 289-294 (1999)

W.Lin：“肋形状和棒直径对粘结强度影响的实验研究”日本混凝土学会会议录。