动手作业小结： 1.大原则：强度破坏>失稳破坏 2.抗整体失稳：I越大越好！ 欧拉公式P=π2EI/KL)2 Footprint优化！ 3抗局部失稳：约束局部，重视细节！
动手作业小结: 1.大原则: 强度破坏>失稳破坏 2.抗整体失稳: I 越大越好! 欧拉公式 P= π² EI /(K L )² Footprint 优化！ 3.抗局部失稳:约束局部,重视细节！
Support Footprint Method-Force flow Example(vertical loads)
Support Footprint Method-Force flow Example(vertical loads)
Support Footprint Method Example (Horizontal loads) 12 12 12 12 风荷F M=Fwh h ⊕ 77777777777777777777777777777777 C2 C3 C 2×(3C5×24+3C4×12)=M 12 144C5+36C5=Fwh C3=Fwh/180 C4=Fwh/360 C1=-Fwh/180 L6↓12412_41246 C2=-Fwh/360
Support Footprint Method Example (Horizontal loads) 风荷 h 12 12 12 12 C C 1 2 C3 C4 C5 M M Fw h 6 12 12 12 6 C5 C4 C2 C1 2 (3 C5 24 3 12 C4 ) M 144 C5 36 C5 Fw h C5 /180 C4 360 C1 180 C2 360 Fw Fw h Fw h Fw h Fw h / / / 12 12
Support Footprint Method Fig.2.5 vertical and horizontal loads together B W H H M M a -H -H -W -W 平衡条件： W十（一0=0 M=Ha M-Ha-We H十（一⑩=0 W十(-W=0 H十（一(H=0
Support Footprint Method Fig. 2.5 vertical and horizontal loads together B W W H a H M M H a H W W e 平衡条件： W＋( －W) ＝0 M=Ha M=Ha=We H ＋( －H) ＝0 W＋( －W) ＝ 0 H ＋( －(H)=0
Support Footprint Method Fig.2.6 Asymmetry building under vertical load M W 。 W ]
Support Footprint Method Fig. 2.6 Asymmetry building under vertical load
Support Footprint Method Fig.2.7 Asymmetry building in vertical and horizontal load Overturn moment M=H a; Twist T=He H a 4M X
Support Footprint Method Fig. 2.7 Asymmetry building in vertical and horizontal load
2.2 Estimating Overall Forces -Vertical dead loads(5~10kN/m2) -Vertical live loads equivalent dead loads(2~5kN/m2) Horizontal wind load Horizontal earthquake load
2.2 Estimating Overall Forces -Vertical dead loads(5 ～10kN/m²) -Vertical live loads = equivalent dead loads(2 ～5kN/m²) - Horizontal wind load - Horizontal earthquake load
2.2 Estimating Overall Forces Horizontal wind load depends upon Building surface area exposed to the wind Wind load intensity of the area
2.2 Estimating Overall Forces Horizontal wind load depends upon - Building surface area exposed to the wind - Wind load intensity of the area
2.2 Estimating Overall Forces Horizontal earthquake load depends upon -Distribution of mass in building -Height of the building -Earthquake intensity
2.2 Estimating Overall Forces Horizontal earthquake load depends upon -Distribution of mass in building -Height of the building -Earthquake intensity Basic definition
2.2 Estimating Overall Forces Procedure to estimate the loads: -Determine building volume or surface area -Apportion total mass or exposed surface area -Determine the EO or wind effect of each component -Sum component effects to reveal overall effect
2.2 Estimating Overall Forces Procedure to estimate the loads: -Determine building volume or surface area -Apportion total mass or exposed surface area -Determine the EQ or wind effect of each component -Sum component effects to reveal overall effect