考慮構件剪力跨深比影響之高強度鋼筋混凝土梁剪力裂縫控制

Shear Crack Control for High-Strength Reinforced Concrete Beams Considering the Shear-Span to Depth Ratio of Member

邱建國(Chien-Kuo Chiu) ； 林芳慶(Fang-Cing Lin) ； 陳少謙(Shao-Cian Chen) ； 紀凱甯(Kai-Ning Chi)

《結構工程》 30卷3期 (2015/09) Pp. 5-26

https://doi.org/10.6849/SE.201509_30(3).0001

摘要

本研究共進行十組四點荷重之簡支梁試驗，其中兩組斷面尺寸為400 mm（寬）×700 mm（深），試體長度為6600 mm，其餘八組試體斷面尺寸為350 mm（寬）×500 mm（深），試體長度為4600 mm及2600 mm各四組，依剪力跨深比分為3.33、3.25、2.75、2.0和1.75五種，皆使用SD685之主筋（6根）搭配SD785之箍筋（箍筋間距300 mm），拉力筋比為2.04%及3.5%，箍筋比為0.21%及0.24%，混凝土強度為70-100 MPa。上述試體規劃主要以剪力跨深比為參數，針對高強度鋼筋混凝土梁於剪力破壞下之剪力裂縫發展行為，除探討國外規範建議公式之適用性外，將依剪力裂縫角度、裂縫寬度（最大值與殘留值）及構件變形角之量化關係，建立梁構件剪力變形角之評估公式，且由混凝土剪力開裂應力、混凝土極限剪應力及構件斷面平均剪應力採線性迴歸之方法，建議各構件性能點之混凝土容許剪應力及箍筋容許應力，並建立高強度鋼筋混凝土梁構件使用性能確保及修復性能確保下，各構件性能點之容許剪應力計算公式。

關鍵字

高強度鋼筋混凝土 ； 剪力強度 ； 裂縫寬度 ； 剪力跨深比 ； 使用性 ； 修復性

並列摘要

This work tests ten full-size simple-supported beam specimens with the high-strength reinforcing steel bars (SD685 and SD785) using the four-point loading. The measured compressive strength of the concrete is in the range of 70-100 MPa. The main variable considered in the study is the shear-span to depth ratio. Base on the experimental date that include maximum shear crack width, residual shear crack width, angle of the main crack and shear drift ratio, a simplified equation are proposed to predict the shear deformation of the HSRC beam member. Besides of the post-earthquake damage assessment, these results can also be used to build the performance-based design for HSRC structures. And using the allowable shear stress at the peak maximum shear crack width of 0.4 mm and 1.0 mm to suggest the design formulas that can ensure serviceability (long-term loading) and reparability (short-term loading) for shear-critical high-strength reinforced concrete (HSRC) beam members.

並列關鍵字

high-strength reinforced concrete ； shear crack ； span-depth ratio ； serviceability ； reparability