Architectural Structures I: Column Design - Stats and Materials - Prof. A. Nichols, Study notes of Environmental Science

Download Architectural Structures I: Column Design - Stats and Materials - Prof. A. Nichols and more Study notes Environmental Science in PDF only on Docsity! Column Design 1 Lecture 21 Architectural Structures I ENDS 231 Su2006abn ARCHITECTURAL STRUCTURES I: STATICS AND STRENGTH OF MATERIALS ENDS 231 DR. ANNE NICHOLS SUMMER 2006 lecture twenty one column design Column Design 2 Lecture 24 Architectural Structures I ENDS 231 S2006abn Design Methods • know – loads or lengths • select – section or load – adequate for strength and no buckling Column Design 5 Lecture 24 Architectural Structures I ENDS 231 S2006abn Cc and Euler’s Formula Column Design 6 Lecture 24 Architectural Structures I ENDS 231 S2006abn Short / Intermediate • Le/r < Cc – where ( ) ..2 1 2 2 SF F C r Kl F y c a ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎣ ⎡ −= ( ) ( ) 3 3 88 3 3 5.. cc C r Kl C r Kl SF −+= Column Design 7 Lecture 24 Architectural Structures I ENDS 231 S2006abn Procedure for Analysis 1. calculate KL/r • biggest of KL/r with respect to x axes and y axis 2. find Fa from Table 10.1 or 10.2 • pp. 361 - 364 3. compute Pallowable = Fa⋅A • or find factual = P/A 4. is P ≤ Pallowable? (or is factual ≤ Fa?) • yes: ok • no: overstressed and no good Column Design 10 Lecture 24 Architectural Structures I ENDS 231 S2006abn Column Charts Column Design 11 Lecture 24 Architectural Structures I ENDS 231 S2006abn Column Charts Column Design 12 Lecture 24 Architectural Structures I ENDS 231 S2006abn Wood Columns • slenderness ratio = L/dmin = L/d1 – d1 = smaller dimension – le/d ≤ 50 (max) – where is the allowable compressive strength parallel to the grain cc FA Pf ′≤= cF ′ Column Design 15 Lecture 24 Architectural Structures I ENDS 231 S2006abn Cp Charts – Appendix A, Table 14 Column Design 16 Lecture 24 Architectural Structures I ENDS 231 S2006abn Procedure for Analysis 1. calculate Le/dmin 2. obtain F´c – compute • KcE =0.3 sawn • KcE = 0.418 glu-lam 3. compute Fc* ≈ FcCD 4. calculate FcE/Fc* and get Cp (table 14) 5. calculate ( )2dL cE cE e EKF = pcc CFF *=′ Column Design 17 Lecture 24 Architectural Structures I ENDS 231 S2006abn Procedure for Analysis (cont’d) 6. compute Pallowable = F′c⋅A • or find factual = P/A 7. is P ≤ Pallowable? (or factual ≤ F′c?) • yes: OK • no: overstressed & no good Column Design 20 Lecture 24 Architectural Structures I ENDS 231 S2006abn LRFD design • limit states for failure 1. yielding 2. buckling λc – column slenderness parameter Ag - gross area ncu PP φ≤ gcrnc AFP == 85.0φ 5.1≤cλ 5.1>cλ E F r Kl y c π λ = r Le Column Design 21 Lecture 24 Architectural Structures I ENDS 231 S2006abn • flanges continuously connected to the web or webs and width-thickness rations < limiting values – no local buckling of flange or web – for – for Compact Sections 5.1≤cλ 5.1>cλ ( ) yλcr F.F c26580= y c cr Fλ .F ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ = 2 8770 Column Design 22 Lecture 24 Architectural Structures I ENDS 231 S2006abn Column Charts