鋼筋混凝土橫箍柱耐震圍束之研究

Design of Seismic Confinement of RC Tied Columns

蔡宛婷(Wan-Ting Tsai)

指導教授 ： 黃世建

國立臺灣大學/工學院/土木工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201601732

摘要

台灣目前建築物仍以鋼筋混凝土結構為主流，然而台灣地狹人稠，隨著都市的發展，樓層越蓋越高，造成底層柱承受相當大的軸向力量。國內耐震設計通常使用抗彎矩韌性構架系統，其設計概念為強柱弱梁，期待塑鉸最先產生在梁構件兩端，而最終底層柱底部產生塑鉸。對於柱構件來說，能夠完成上述耐震機制的條件就必須要有足夠的變形能力。為了達到此目的，就必須仰賴良好的圍束效果。目前國內柱圍束耐震相關規定與ACI 318-11規範相同，兩者皆沒有考慮軸力的影響。
但近年ACI 318-14規範已將軸力因素納入考量，並規定在高軸力下，必須使用兩端耐震彎鉤之繫筋，並且圍束每根主筋。由於台灣施工習慣上，大多採現場組裝鋼筋籠的方式施工，因此目前國內並沒有足夠的吊車設備，無法允許高樓層建築在新建時全面採用預組鋼筋籠的方式，只能採用現場組裝鋼筋籠的方式施工。若完全比照ACI 318-14的規定，在主筋密集的排列之下，若全面使用兩端耐震彎鉤之繫筋，會增加施工上的困難。考量國內現有之施工特性，能否維持目前使用90°-135°彎鈎或隔根圍束主筋的前提下，依美國ACI 318-14之規定配置足夠的橫向鋼筋，確保柱桿件仍能擁有良好的變形能力，即為本研究之目標。

關鍵字

柱 ； 圍束箍筋量 ； 高軸力 ； 側向變形 ； 箍筋配置細則

並列摘要

Reinforcement concrete structure is the major building system in Taiwan. In metropolitan area of Taiwan with a high population deansity, construction of high-rise buildings for residential purpose is a necessity. It leads to very high axial load in the lower story columns. Moment resisting frames is often used to resist earthquake in Taiwan. This system behaves well during earthquake, since they have the strong-column weak-beam assemblages to dissipate the energy. Flexural yielding should occur at both ends of beams, and column ends at base can be yielded at final stage. To sure this mechanism in ductile manner, the columns should be well confined. Current column provisions on confinement in Taiwan code, similar to ACI 318-11code, the influence of high axial force on reducing deformation capacity is not concidered.
Recently, ACI 318-14 requires a increased confining reinforcement for column with higher axial load. In addition, ACI requires that all the column longitudinal bars be engaged with seismic hooks when column axial load is high. Due to the limited accessibility of construction facilities, the provisions to use seismic hooks for both end of cross-ties are difficult to follow in Taiwan. Due to this problem of the construction in Taiwan, the purpose of this study is to investigate the applicability of the crosstie with a seismic hook at one end and a 90-degree hook at the other end. Total of 8 column specimens were tested in this study, and the use of crosstie with a 90-degree hook at one end is allowed.

並列關鍵字

columns ； column confinement ； high axial load ； lateral deformation ； crosstie detail

參考文獻

[8] 張豐展，「高強度鋼筋混凝土柱圍束效應研究」，碩士論文，國立台灣大學土木工程學系，台北，民國99年。

[10] 陳盈璋，「高強度鋼筋混凝土柱耐震圍束效應之研究」，碩士論文，國立台灣大學土木工程學系，台北，民國100年。

[15] 廖苑儀，「普通強度鋼筋混凝土柱耐震圍束之研究」，碩士論文，國立台灣大學土木工程學系，台北，民國103年。

[2] ACI Committee 318, “Building Code Requirement for Structural Concrete (ACI 318-11) and Commentary(ACI 318R-11),” American Concrete Institute, Farmington Hills, Mich., 2011, 503 pp.

[3] ACI Committee 318, “Building Code Requirement for Structural Concrete (ACI 318-14) and Commentary(ACI 318R-14),” American Concrete Institute, Farmington Hills, Mich., 2014, 519 pp.