Study on the Instantaneous Center of Bolted Connections due to Eccentrically Loads

鋼骨托梁式接合根據不同螺栓排列、載重位置以及載重角度等因素，考慮不同外力作用時產生之偏心載重，造成彎矩與剪力共同作用於樑柱接頭。AISC規範對螺栓接合之分析之過程牽涉複雜運算，規範雖對螺栓之分析有提供查表方法，但僅針對特定排列組合型式、外力角度以及水平偏心之查表值，並未提及當不同角度載重作用與任意螺栓排列型式幾何形狀時之詳細分析過程，且規範並未提及垂直偏心之產生之影響。 回顧AISC期刊文獻，Brandt, G.D.[5]與Marsh, Cedric.[8]分別提出快速決定設計力的方法，Brandt, G.D.所提的方法設計力較為精確，但是計算略為繁複，Marsh, Cedric.所提出的方法雖然計算簡單，但是有高估疑慮。 本研究將以AISC規範為出發點討論螺栓接合評估的合理性，由AISC規範內提供之各斷面與角度外力作用之依據，以本研究發展之近似公式法推估任意角度的螺栓接合之合理值，根據研究顯示近似公式可以合理推估理論強度。 本研究亦將高度與角度影響載重之複雜的計算包含彈性、極限數值公式以程式輔助，擺脫規範所提供之特定限制，針對任何角度、不同的螺栓幾何排列，甚至不同強度之螺栓同時作用下的情況供設計者參考，可用於設計或是分析現有之螺栓接合，對螺栓接合強度之分析提供較合理之設計依據。When eccentricity occurs in the plane of the faying surface, the bolt must be designed to resist the combined effect of the direct share and the additional shear from the induced moment. Two analysis methods for bolted connections of eccentrically loaded are the elastic method and the ultimate strength method. The ultimate analysis, which specified in AISC design manuals, has been used for the analysis of eccentrically loaded connections which is bolted. In the current AISC design manual, tabulated solutions for eccentric loads inclined at specified angles from vertical are provided. For the cases which inclined angles are in the range of 75°≦θ≦360°, the current AISC manual does not furnish available tables to apply. This study to evaluate the strength of eccentrically loaded connections, which are not limited to the bolt patterns listed in current AISC manuals, are presented and compared. A numerical procedure for the analysis of eccentric loads that are inclined at any angles from vertical is furnished. This will also accomplish a better solution for practicing engineer in their routine design.Abstarct / Chinese....................................................................................... i Abstract / English....................................................................................... ii Table of Contents...................................................................................... iii Table List ....................................................................................................v Figure List................................................................................................ vii Chapter 1 Introduction .............................................................................1 1.1 Background.................................................................................1 1.2 The Needs of This Research .......................................................2 1.3 Purpose of Research....................................................................3 Chapter 2 Analysis Method .....................................................................4 2.1 Bolts subjected to eccentric loads...............................................4 2.2 Method 1 - Elastic method.........................................................4 2.3 Method 2 - Ultimate Analysis..................................................13 2.4 Method 3 - Proposed by Brandt extrapolation formula...........21 2.5 Method 4 - Marsh.....................................................................29 2.6 Method 5 - Tables in 2005-AISC design manual ....................31 2.7 Method 6 - Iwankiw's method in 1989-ASD design manual..34 2.8 Method 7 - Proposed method by this study .............................37 2.9 Angular correction for the first quadrant..................................40 Chapter 3 Examples for Analysis ..........................................................43 3.1 Inclined Angle θ = 0°/ xp = 4 in., yp = 0 in................................43 3.2 Inclined Angle θ = 36.87°/ xp = 20 in., yp = 5 in. ...................56 3.3 Inclined Angle θ = 0°/ xp = 16 in., yp = 10 in............................70 3.4 Inclined Angle θ = 30°/ xp = 16 in., yp = 10 in..........................84 3.5 Inclined Angle θ = 80°/ xp = 16 in., yp = 0 in............................99 Chapter 4 Graphics of Results .............................................................114 4.1 Accuracy .................................................................................116 4.2 Computational complexity......................................................119 4.3 Suitable situation.....................................................................120 4.4 Restriction...............................................................................121 Chapter 5 Conclusions .........................................................................123 References...............................................................................................124 Appendix − A..........................................................................................125 Appendix − B..........................................................................................13