Tóm tắt lý thuyết chương 4 Môn Kết cấu bê tông & bê tông cốt thép | Đại học Sư phạm Kỹ thuật Thành phố Hồ Chí Minh

lOMoAR cPSD| 58759230 Steel Structures
Chapter 4 Steel Columns Contents
1. Introduction 2. Axially loaded Solid
columns 3. Axially loaded Open-web
columns 4. Eccentrically loaded
columns 5. Details of columns 2 lOMoAR cPSD| 58759230 Introduction 1. General
➢ Columns – structural members transmit
load from above members through footings to the soil.
➢ Axially loaded columns – subjected to axial forces
➢ Eccentrically or non-axially columns –
subjected to axial forces and bending moments . 3 Introduction 2. Types of columns Section • Solid, open-web • Constant / various sections. Internal forces • Axially loaded columns • Eccentrically loaded columns lOMoAR cPSD| 58759230 4 Introduction
3 . Effective lengths of columns 0 L L 5 Introduction
4. Slenderness of columns A n
x Lx ; y Ly in I ix iy
Best for axially loaded columns: x y lOMoAR cPSD| 58759230 Slenderness requirement max max max( x, y) 6 7
Axially loaded solid columns 1. Column sections
2. Strength requirement lOMoAR cPSD| 58759230
3. Global stability requirement
4. Local stability requirement 5. Problems 6. Examples 8 lOMoAR cPSD| 58759230
Axially loaded solid columns 1. Column sections 9
Axially loaded solid columns 1. Column sections lOMoAR cPSD| 58759230
Axially loaded solid columns 10
2 . Strength requirement N f c n A N: design axial force
A n : effective (net) area of the member cross section.
f : design strength of the mat. used
c : working condition co-efficient 11 lOMoAR cPSD| 58759230
Axially loaded solid columns Axially loaded solid columns 2 EI 3. Global stability m in 2 L requirement 2 •
Elastic buckling load: Ncr 2 2EIL20min • Elastic buckling stress: cr NAcr 2AEIL2min0
A2 EI Lmin 2 E L0 L imin imin •
Longitudinal bending co-efficient: fcry 22fEy 12 lOMoAR cPSD| 58759230
Axially loaded solid columns
3 . Global Stability requirement N f max f c mi n A E • f If 0 2 , 5: 1 0,073 5 , 53 E • If 2 ,5 4 ,5: f f f 2 , 1 47 13 0 ,371 , 27 3 0 ,0275 , 5 53 E E E 332 • If 4 , 5: 2 51 13 lOMoAR cPSD| 58759230
Axially loaded solid columns
Axially loaded solid columns Thin plate under compression
4. Local Stability requirement • 14 lOMoAR cPSD| 58759230
Axially loaded solid columns lOMoAR cPSD| 58759230
Axially loaded solid columns
Axially loaded solid columns 0,8 : ; 0,8 4 : 4 16 5. Basic problems
Determine load-carrying capacity max N b c fAn; N c f A; N min N b, N Verifications max lOMoAR cPSD| 58759230
Axially loaded solid columns N c f ; N c f hw hw bo bo An A tw tw t f t f 17
Axially loaded solid columns 5. Basic pr Assume = 40- oblems 100 or = 0-1 Design Select a section Change the Determine max section and Not OK Check strength OK and stability req’s End h=(1 1,15)b ; ly lx b ;h tf=8 40mm ; tw=6 16mm yc yc y gt x gt 18 lOMoAR cPSD| 58759230
Axially loaded solid columns
5 . Basic problems Design 19 lOMoAR cPSD| 58759230
Axially loaded solid columns
Axially loaded solid columns 6. Example 20 6. Example 21 lOMoAR cPSD| 58759230
Axially loaded solid columns
Axially loaded solid columns 6. Example 22 6. Example 23 lOMoAR cPSD| 58759230
Axially loaded solid columns
Axially Loaded Open-Web Columns 1. Introduction
2. Behavior of open-web columns
3. Tính toán cột rỗng chịu nén úng tâm
4. Thiết kế cột rỗng 24 lOMoAR cPSD| 58759230
Axially Loaded Open-Web Columns 1. Introduction Laced open-web column Battened open-web column (2 branches) (2 branches) 25 lOMoAR cPSD| 58759230
Axially Loaded Open-Web Columns
Axially Loaded Open-Web Columns 1 .Introduction Maintenance conditions Large load Light load 26 1. Introduction Laced open-web columns Battened open-web columns Lattice: atleast L40x5 27 lOMoAR cPSD| 58759230
Axially Loaded Open-Web Columns
Axially Loaded Open-Web Columns
2. Behavior of open-web columns 28 .
2 Behavior of open-web columns
About y-y axis BendinginOxzplane: asasolidcolumn I I I y 2 y 0 y 0 i i y y 0 A 2 A A f f l l y y y i i y y 0 29