實尺寸高強度鋼筋混凝土梁之剪力裂縫行為研究

Study on the Shear Cracking Behavior of the Full-Size High Strength Reinforced Concrete Beams

邱建國(Chien-Kuo Chiu) ； 陳崇慶(Tsung-Ching Chen) ； 林芳慶(Fang-Ching Lin) ； 紀凱甯(Kai-Ning Chi)

《結構工程》 29卷4期 (2014/12) Pp. 19-43

https://doi.org/10.6849/SE.201412_29(4).0002

摘要

本研究共進行十組四點荷重之簡支梁試驗（跨深比為3.33），其中八組於左右兩端之等剪力段，配置不同之箍筋間距（200mm及300mm），剩餘兩組則無配置箍筋。壓力筋配置均為2根，拉力筋則分別以8根及12根進行配置，且均為D25之SD685鋼筋，斷面尺寸均為400mm（寬）×700mm（深），保護層厚度均為40mm，箍筋採用D13之SD420W及SD785鋼筋。依本研究實驗結果可知，就長期荷重(靜載與活載作用)下之使用性能確保而言，梁長期容許應力值可取ACI 318-11所建議混凝土剪力強度之0.75倍。就短期荷重（中小規模地震）下之修復性能而言，本研究擬建議採用ACI 318-11之混凝土剪力強度計算公式進行此性能點檢核。就高強度鋼筋混凝土梁構材而言，依本研究試驗結果可知其受力後之剪力裂縫殘留總寬度與最大寬度比值約為4.5；為保守起見，本研究建議該比值可取4.0以進行分析時殘留剪力裂縫最大值推估。此外；尖峰變形角時剪力裂縫最大寬度與殘留最大寬度之比值，本研究建議高強度鋼筋混凝土梁之適用值為2.5。

關鍵字

高強度 ； 鋼筋混凝土 ； 剪力裂縫 ； 梁試體 ； 殘留裂縫寬度 ； 使用性能 ； 修復性能

並列摘要

The main propose of this work is to investigate the shear crack development and suggest the design formulas that can ensure serviceability and reparability for shear-critical high-strength reinforced concrete (HSRC) beam members based on the experimental data of ten full-size simple-supported beam specimens (Span-depth ratio is 3.33). According to the experimental results, the design formulas that can ensure the serviceability and reparability are recommended for shear-critical HSRC beam members. Based on the crack development of each specimen, the average ratio of the residual total shear crack widths to the residual maximum shear crack width for the HSRC beam specimens is approximately 4.5; then, in the crack-based assessment, this work recommends setting the ratio as 4.0 to estimate residual maximum shear cracking. Additionally, the ratio of maximum peak shear crack width to residual maximum crack width, it can be increased by shortening stirrup spacing and increasing stirrup strength, and its overall average value is 2.44. This work suggests the applicable value of a HSRC shear-critical beam to be 2.5. Besides of the post-earthquake damage assessment, these results can also be used to build the performance-based design for HSRC structures.

並列關鍵字

high strength ； reinforced concrete ； shear crack ； beam specimens ； residualcrack width ； serviceability ； reparability