Damages and Earthquake Resistant Performance of Steel Frame Structures with Self Strain Stress (Faculty of Architecture and Structural Engineering) Yutaka NIHO, Masaru TERAOKA (Professor Emeritus of KNCT) Yasuhiro FUKUHARA ABSTRACT This paper describes the earthquake resistant performance of steel frame structures with self strain stresses. Both self strain stress due to differential settlement of the structures and that due to thermal strain are considered here. Firstly, this paper briefs a method for calculation on both maximum strength and horizontal stiffness of the structures. And secondly, this paper shows a load-displacement curve for each structure and investigates effects of self strain stresses on both the maximum strength and the horizontal stiffness. Finally, this paper concludes that self strain stress effects strongly both maximum strength and horizontal stiffness of the steel frame structures. keywords Steel Frame Structure, Differential Settlements, Thermal Strain, Self Strain Stress, Earthquake Resistant Performance 40 1),2) 3) 4) 2.010-3 4) 4) 721 5) 6/1000 5) 6) 10) 10) 11)
6) 5 1 2 3 4 5 1, 3) L60m h=4m 4m φ19 SS400 σ y = 23.5 10 2 kn/mm 2 E = 205.8kN/mm 2 Table1 4) 7 Fig.1 5 7) S S 2 5 (Fig.2 ) ( No.1, No.2, No.3, No.4) 1 1 w= w0 x 2 x ( x< x0) n L n L 1 1 w= w0 x1 2 x1 ( x x0) n1 L n1 L x 1 = L x,, n 1 = 1 n (S No.5) (1.1) 2π w= w0 sin x (1.2) L w w 0 x 0 x n Fig.2 No.1No.2No.3No.4 2/15, 4/15, 6/15, 1/2 w 0 1),4)w 0 = 0, 37.5, 75.0, 112.5, 150mm w 0 /L=1/1600 1/8001/5331/400 Fig.1 Models [mm] Table.1 Sectional and Material Properties of Braces SS400 19 mm 283.5 mm 2 l 0 5657. mm E 205.8 kn/mm 2 σ y 235.210-3 kn/mm 2 N p 66.62 kn 1.1410-3 212
1) 20 o 30 o C Δt 35 o C Δt = 0, 20, 25, 30, 35 o C Q y K 0 Fig.3 Q Fig.4 (1) Fig.5 ε 0d ε 0d = ( h w) l l i+ 1 2 2 +Δ + i 0 l 0 (2.1) Δ w= w w (2.2) Fig.2 Differential Settlements Fig.3 An Example of Analytical Models Fig.4 Hysteresis Characteristics for Braces l 0 Fig.5 Calculation on Strain hll 0 w i i (1) Fig.5 θ j j θ j Δwj = (3) l Fig.6(a) Fig.6(a) l h Δw 312
d 0T = α Δt l, xj dt 1 = α Δt l (4.1), (4.2) 2 (b) = (a) (c) + (d) Fig.6 Deformation of a Steel Frame Structure with Thermal Stress Fig.7 Hysteresis Characteristics for Braces of Structures with Thermal Stress Fig.8 Combination of two Hysteresis Characteristics for Braces Fig.6(a) Fig.6(b) Fig.6(c)(d) d 0T d T d 0T d T l xj j α1.010-5 [1/ o C] Fig.6(d) d T δ T Fig.7 δ T 45 o d d T δ δ = 1 2 d (5) d 0T (5)δ 0T δ 0T ε 0T δ 0T ε 0T = (6) l 0 ε 0T ε 0d ε 0 ε = ε + ε (7) 0 0d 0T Fig.7 Fig.5 Fig.7 Fig.8 d yt q T dyt = dy dt, qt = 2Kp δt (8.1), (8.2) d y N p δ y (5) K p 45 o k Kp 1 = k (9) 2 d 0 (7)ε 0 δ 0 δ = ε l (10) 0 0 0 412
δ 0 (5) d d 0 d 0 q Fig.9 d 0 q Fig.10 Q y K 0 Q y Q d Q y Fig.9, Fig.10, Table 2 Fig.1 7 Table 1 Q ini y K ini 0 329.8[kN] 36.10[kN/mm 2 ] Q y n = q (11) j= 1 yj n q yj (a) (a) (b) d 0 d T (b) d 0 d T (c) d T < d 0 <d yt (c) d T < d 0 <d yt (d) d 0 d yt (d) d T < d 0 <d yt + d T (e) d 0 d yt + d T Fig.9 Relations on Strength and Displacement for Panels (Same Direction) Fig.10 Relations on Strength and Displacement for Panels (Opposite Direction) Table 2 Horizontal Force q and Displacement d d 0 q (Fig.9) d 0 q (Fig.10) d 0 d T (Fig.9(b)) d T <d 0 <d yt (Fig.9(c)) d 0 d yt (Fig.9(d)) d 0 d T (Fig.10 (b)) d T < d 0 < d yt (Fig.10 (c)) d yt <d 0 d y +d T (Fig.10 (d)) d 0 >d y +d T (Fig.10 (e)) q y1 2 K p d y1 K p d y1 2 K p d y1 K p d y1 q y2 q y1 + q y1 + K p (d y2 d y1 ) K p (d y2 d y1 ) q y1 + 2 K p (d y2 d y1 ) q y1 +K p d y1 q y3 q y2 + K p (d y3 d y2 ) d y1 d T d 0 d yt d 0 d 0 + d T d 0 d T 2d 0 d y d y d y2 d yt d T d 0 + d yt d 0 + d T d y3 d 0 + d yt 512
I~I 1 列 I~I 同 I~I I~ グ 1 判 対 I"<?~ ~ 1~~'1 ~ [;A ~ ~OT ~ T
~ wo~ 200~r 一二 ~ ~ ~ ~ Wo ~ wo ~ wo ~ ~
,~J~~ ~ ~~~l20 L1t ~ 35 0C L1t ~ 30 0C L1t ~ 25 0C ~ L1t ~ 35 0C L1t ~ 30 0C L1t ~ 25 0C ~ L1t ~ 35 0C L1t ~ 30 'C L1t ~ 25 'C L1t ~ 20 'C ~ L1t ~ 35 0C L1t ~ 30 'C L1t ~ 25 'C L1t ~ 20 'C ~ No. l(wo~ 150mm) No.4 (wo~ 150mm) L1t ~ 35 0C L1t ~ 30 'C L1t ~ 25 'C L1t ~ 20 'C ~ L1t ~ 35 0C L1t ~ 30 'C ~ L1t ~ 20 'C ~ ~400
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