無預力鋼絞線主筋混凝土梁反復載重行為

本研究主要探討無預力鋼絞線取代傳統竹節鋼筋作為梁縱向主筋的結構行為，並提供一個新的鋼絞線錨定方式於接頭，其方法能夠有效改善鋼絞線因表面紋路與傳統竹節鋼筋不同的問題，為此設計五座大尺寸梁柱接頭試體，依鋼絞線取代率的不同，可分為三個等級，B等級(全鋼筋)、BSR等級(混筋)、BST等級(全鋼絞線)，3座為卜字形試體，涵蓋以上所敘述的三個等級；2座為十字形試體，只有BSR等級以及BST等級。試驗方式為於梁端執行反復加載，柱上下兩端以預力鋼棒固定，模擬韌性抗彎構架抵抗側向力之真實結構行為，加載歷時按照ACI 374.1之規定，以利將來若與其他梁柱接頭試體進行比較與資料庫之建立。除此之外，本文亦對無預力鋼絞線梁於使用載重下裂縫與撓度控制進行探討，根據陳育銘六座簡支梁試體之試驗結果，指出全鋼筋試體與混筋(50%)試體若使用ACI 318-14之鋼筋間距限制式能有效控制其裂縫發展；撓度控制部分則指出若使用我國現行規範之等效慣性矩法能夠保守評估全鋼筋試體與混筋(50%)試體之即時撓度，除此之外，利用最小梁深修正法則指出混筋(50%)試體與全絞線試體若分別將其梁深提升12%與40%，即具有等同於傳統鋼筋混凝土梁之撓度控制能力。在強度設計方面，根據本研究之梁柱接頭試驗結果與陳育銘簡支梁的試驗結果皆指出，無論鋼絞線取代率的多寡，根據現行規範所得出的標稱計算彎矩都能夠得出較保守的結果。全鋼筋試體、混筋試體以及全絞線試體之消能狀況相近，差別主要為韌性容量之多寡，其中，全鋼筋試體與混筋試體均有顯著的韌性容量，最後於文末將提出一套針對鋼鉸線取代傳統竹節鋼筋之設計方法，其中包括三大部分，分別為使用狀態設計、極限狀態設計，以及細部設計。

關鍵字

鋼絞線；梁柱接頭；簡支梁；裂縫控制；撓度控制；錨定方式；鋼筋間距

並列摘要

This study mainly discusses the structural behavior of the unstressed steel strands replacing the traditional steel bars as the longitudinal reinforccement of the beam, and provides a new steel strand anchoring method for the joints. The method can effectively improve the steel strands with different kind of surface texture. Five real-size beam-column joint specimens are designed for testing how unstressed steel strands work in beam-column joint. According to the different replacement rate of steel strands, they can be divided into three grades, B grade (full reinforcement), BSR grade (mixed reinforcement), BST grade. (All steel strand reinforcement).3 seats are the T-shaped test pieces, covering the three grades described above; 2 seats are cross-shaped test pieces, only BSR grade and BST grade. The test method is to perform the cyclic loading on the beam end, and the upper and lower ends of the column are fixed by prestressed steel bars to simulate the true structural behavior of the moment-resisting frame against the lateral force. The loading duration is in accordance with the provisions of ACI 374.1, in order to benefit other beams in the future and help database established. In addition, this paper also discusses the crack control and displacement control of beams with unstressed steel strands under working load. According to Chen's test results and analysis, it can be understood that using ACI 318-14 can effectively control crack developing on the specimens of B grade and BSR grade. Speaking of displacement control of beam, if the effective moment of inertia method in current code is used, the instantaneous deflection of specimens of B grade and BSR grade can be conservatively evaluated. Furthermore, if the B grade and BSR grade specimens increase their beam depth by 12% and 40% respectively, they have the same deflection control ability as the conventional reinforced concrete beams. In terms of strength design, according to the results of the beam-colum joint test and the test results of Chen Yuming's beam, it is pointed out that no matter the amount of replacement of the strand, the nominal calculated bending moment according to the current specification are conservative. Although the energy dissipation status of all specimens are similar, the difference is mainly the toughness capacity. Among them, the B grade specimen and BSR grade specimen have significant toughness capacity. At the end of the text, a design method for replacing traditional steel bars will be proposed, including three parts, one is the control of cracks and displacement under working load, another is the design of unstressed steel strands member under ultimate strength, and the other is the design of sectional detailing.