方形New RC柱受高強度橫向鋼筋圍束作用下之應力應變曲線模式

Abstract

於高層樓建築中，建築物底層中之柱承受相當高之軸向壓力，使用高強度混凝土材料能有效降低斷面尺寸、減少材料用量、增加建築物室內空間、降低生產成本等優點，然而高強度混凝土材料與傳統混凝土力學行為有相當大的差異，由於高強度混凝土於破壞時呈現脆性破壞，材料特性也不盡相同，其原先之應力應變預測模式已無法準確預測，故本研究希望利用本土化材料及施工方式，建立高強度混凝土於圍束效應下之應力應變模式。 本研究主要利用改變箍筋間距、改變橫向鋼筋量之手段，並嘗試放寬規範，觀察柱構件中核心混凝土受到圍束效應程度上的不同，所表現出之韌性行為及其應力應變曲線，並且整理歸納出適用於本土化材料之應力應變模式。施作不同箍筋間距及橫向鋼筋量，透過柱軸壓實驗對圍束效應之影響予以量化，並以韌性比對柱構件韌性行為進行量化分析。柱軸壓實驗結果發現減少箍筋間距及增加橫向鋼筋量能有效提升柱構件之變形能力，增加其韌性容量，並改變其脆性破壞之特性，顯示增加圍束效應能有效提升柱構件軸壓行為之表現，使其具備更好之耐震消能之能力。 利用本研究實驗結果並且參考現有應力應變模式，對部分參數進行回歸分析，並以軸壓試驗的方式，提出適合本土化材料之高強度混凝土應力應變模式，以供未來使用此材料進行結構設計時，設計高強度鋼筋混凝土參考之用。

Column members placed below high-rise constructions usually bear relatively high vertical loads. The application of high-strength concrete offers several advantages, such as reducing sizes of cross-section and material usage, increasing interior space, and minimizing production costs. However, there are significant differences in mechanics between high-strength concrete material and normal concrete in terms of their characteristics of materials. One of the examples is that high-strength concrete demonstrates brittle fracture after destruction. Hence, the original stress-strain model fails to perform accurate prediction. The study aimed to utilize local materials and construction approaches to build another stress-strain model under the circumstance of high-strength concrete with confinement. By altering space of stirrup and lateral reinforcement, the research explored how concrete core within column members performs toughness as well as stress and strain while experiencing different levels of confinement; furthermore, a model of stress and strain adaptable to local was established. The purpose of this research was to propose an adoptable stress and strain model for local materials via the axial compression experiment and regression analysis on partial parameters with reference to the current model, as a foundation for any structural design with high-strength concrete materials in the future. f