๐Ÿ“š ์„ค๊ณ„ 6์ข… ๋น„๊ต (์–ด๋А ๊ธฐ์ค€์˜ ์–ด๋А ์‹์„ ์ผ๊ณ , ๊ฐ™์€ ์˜ˆ์ œ์—์„œ ์–ผ๋งˆ๊ฐ€ ๋‚˜์˜ค๋Š”์ง€)๐Ÿ  SJ Tech ํ™ˆ๐Ÿ“ง strustar@konyang.ac.kr๋‹ซ๊ธฐ

๐Ÿ”— ์ •์ฐฉ, ์ด์Œ ์„ค๊ณ„, ๊ธฐ์ค€ 6์ข… ๋น„๊ต (์กฐํ•ญ, ์‹, ์›๋ฌธ, ๊ณ„์‚ฐ)

์กฐํ•ญ ํด๋ฆญ โ†’ ์›๋ฌธ PDF ๊ทธ ์ชฝ์‹ ๋ฒˆํ˜ธโ†— ์ฐธ์กฐ ์กฐํ•ญํŒŒ๋ž€ ๋ธ”๋ก = ์˜ˆ์ œ ๊ฐ’ ๋Œ€์ž… ๊ณ„์‚ฐ์ ์„  ์นด๋“œ = ์ฐธ๊ณ ์šฉ(๋น„๊ต ์—ด ์•„๋‹˜)
RCKDS 14 20 52์ฝ˜ํฌ๋ฆฌํŠธ๊ตฌ์กฐ ์ •์ฐฉ, ์ด์Œ ์„ค๊ณ„๊ธฐ์ค€ (2024)๊ตญํ† ๊ตํ†ต๋ถ€, KCSC ๋ฌด๋ฃŒRCKDS 14 20 10์ฝ˜ํฌ๋ฆฌํŠธ๊ตฌ์กฐ ํ•ด์„, ์„ค๊ณ„ ์›์น™ (2021)๊ตญํ† ๊ตํ†ต๋ถ€, KCSC ๋ฌด๋ฃŒ, ์ฐธ์กฐFRPKDS 14 20 68GFRP ๋ณด๊ฐ•๊ทผ ์ฝ˜ํฌ๋ฆฌํŠธ๊ตฌ์กฐ ์„ค๊ณ„๊ธฐ์ค€ (2024)๊ตญํ† ๊ตํ†ต๋ถ€, KCSC ๋ฌด๋ฃŒFRPKDS 24 50 05GFRP ๋ณด๊ฐ•๊ทผ ์ฝ˜ํฌ๋ฆฌํŠธ๊ต ์„ค๊ณ„๊ธฐ์ค€ (2024)๊ตญํ† ๊ตํ†ต๋ถ€, KCSC ๋ฌด๋ฃŒ์ฐธ๊ณ KCS 24 50 05GFRP ๋ณด๊ฐ•๊ทผ ์ฝ˜ํฌ๋ฆฌํŠธ๊ต ์‹œ๊ณต ์‹œ๋ฐฉ (2024)๊ตญํ† ๊ตํ†ต๋ถ€, KCSC ๋ฌด๋ฃŒ, ์‹œ๊ณต ์‹œ๋ฐฉ์„œ์ฐธ๊ณ KDS 14 20 68 ๋ถ€๋กGFRP ๋ณด๊ฐ•๊ทผ ์žฌ๋ฃŒ, ํ’ˆ์งˆ ์‹œ๋ฐฉ ์—ญํ•  (2024)KDS 14 20 68 : 2024 ๋ฐœ์ทŒ, ๊ฐœ์ •์•ˆ์—์„œ KCS ์ด๊ด€ ์˜ˆ์ •์ฐธ๊ณ KEC ์ž ์ •์ง€์นจ 2022๋„๋กœ๊ณต์‚ฌ GFRP ์ž ์ • ์„ค๊ณ„, ์‹œ๊ณต์ง€์นจ (2022)ํ•œ๊ตญ๋„๋กœ๊ณต์‚ฌ, ๋‚ด๋ถ€ ์‹ค๋ฌด์ง€์นจ(๋ณด์œ  ์ž๋ฃŒ, ๋น„๊ณต๊ฐœ), ํŒŒ์ผ ์—†์Œ(๊ณต์‹ ๋งํฌ)FRP ํ•ด์™ธACI 440.1R-15FRP ๋ณด๊ฐ•๊ทผ ์ฝ˜ํฌ๋ฆฌํŠธ ์„ค๊ณ„, ์‹œ๊ณต ์ง€์นจ (2015)ACI, ์ €์ž‘๊ถŒ(๋กœ์ปฌ ์—ด๋žŒ), ํŒŒ์ผ ์—†์Œ(๊ณต์‹ ๋งํฌ)FRP ํ•ด์™ธACI 440.11-22GFRP ๋ณด๊ฐ•๊ทผ ์ฝ˜ํฌ๋ฆฌํŠธ ๊ตฌ์กฐ ์„ค๊ณ„์ฝ”๋“œ (2022)ACI, ์ €์ž‘๊ถŒ(๋กœ์ปฌ ์—ด๋žŒ), ์Šค์บ”๋ณธ, ํŒŒ์ผ ์—†์Œ(๊ณต์‹ ๋งํฌ)FRP ํ•ด์™ธAASHTO-2018GFRP ๋ณด๊ฐ• ์ฝ˜ํฌ๋ฆฌํŠธ๊ต ์„ค๊ณ„์ง€์นจ 2ํŒ (2018)AASHTO, ์ €์ž‘๊ถŒ(๋กœ์ปฌ ์—ด๋žŒ), ์Šค์บ”๋ณธ, ํŒŒ์ผ ์—†์Œ(๊ณต์‹ ๋งํฌ)
โš  ์–ด๋–ค ์›๋ฌธ์ด ์—ด๋ฆฌ๋‚˜ (๊ธฐ์ค€๋งˆ๋‹ค ๋‹ค๋ฆ„)
KDS, KCS (๊ตญํ† ๊ตํ†ต๋ถ€ ๊ณ ์‹œ)  โ†’  ๋ˆ„๊ตฌ๋‚˜ ์—ด๋žŒ. ์ €์ž‘๊ถŒ๋ฒ• ์ œ7์กฐ ๋น„๋ณดํ˜ธ ์ €์ž‘๋ฌผ์ด๋ฉฐ ๊ตญ๊ฐ€๊ฑด์„ค๊ธฐ์ค€์„ผํ„ฐ์—์„œ ๋ฌด๋ฃŒ๋กœ ๋ฐ›์„ ์ˆ˜ ์žˆ์Œ.
ACI, AASHTO (ํ•ด์™ธ ๊ธฐ์ค€)  โ†’  ์ €์ž‘๊ถŒ ์ž๋ฃŒ๋ผ ์ด PC์— ์žˆ๋Š” ์‚ฌ๋ณธ์œผ๋กœ๋งŒ ์—ด๋žŒ. ๋งํฌ๊ฐ€ ์•ˆ ์—ด๋ฆฌ๋ฉด ๋ฐœํ–‰์ฒ˜ ๊ณต์‹ ๋ฏธ๋ฆฌ๋ณด๊ธฐ, ์ƒ์ ์œผ๋กœ ์—ฐ๊ฒฐ๋จ.
๋„๋กœ๊ณต์‚ฌ ์ง€์นจ  โ†’  ๋ฐœ์ฃผ์ฒ˜ ๋‚ด๋ถ€ ์ž๋ฃŒ๋ผ ๋น„๊ณต๊ฐœ. ์กฐํ•ญ ๋ฒˆํ˜ธ์™€ ๋‚ด์šฉ๋งŒ ํ‘œ์— ์˜ฎ๊ฒจ ์ ์—ˆ๋‹ค.
์›๋ฌธ PDF๋Š” ์›จ์ผ, ํฌ๋กฌ์—์„œ ์—ด๋ฉด ํ•ด๋‹น ์ชฝ๊ณผ ์œ„์น˜๊นŒ์ง€ ์ž๋™์œผ๋กœ ์ด๋™ํ•จ.
๐Ÿงฎ ์˜ˆ์ œ ๊ฐ’$b$ = 400 mm, $h$ = 600 mm, $f_{ck}$ = 30 MPa, $d_b$ = 25.4 mm, $V_u$ = 180 kN, ํ™•๋ณด = 1,200 mm
๐Ÿ“Š ๊ธฐ์ค€ 6์ข… ๋น„๊ต ์ฐจํŠธ (๊ฐ™์€ ์˜ˆ์ œ์—์„œ ๊ธฐ์ค€๋ณ„ ๊ฐ’)
๋…ธ๋ž€ ํ…Œ๋‘๋ฆฌ = ์ง€๊ธˆ ๊ณ ๋ฅธ FRP ๊ธฐ์ค€๋ถ‰์€ ์ ์„  = ๋ชจ๋“  ๊ธฐ์ค€์— ๊ฐ™์€ ํ•œ๊ณ„๋ถ‰์€ ์งง์€ ์„  + ์ˆซ์ž = ๊ทธ ๊ธฐ์ค€๋งŒ์˜ ํ•œ๊ณ„
์•ฝ์นญ KDS 14 = KDS 14 20 68 (๊ฑด์ถ•, ์ผ๋ฐ˜), KDS 24 = KDS 24 50 05 (๊ต๋Ÿ‰), ACI 15 = ACI 440.1R-15, ACI 22 = ACI 440.11-22, AASHTO = AASHTO GFRP ๋ณด๊ฐ• ์ฝ˜ํฌ๋ฆฌํŠธ๊ต ์„ค๊ณ„์ง€์นจ 2ํŒ (2018)
์ตœ๋Œ€ ์ด์šฉ๋ฅ  (์†Œ์š”/ํ™•๋ณด)- - ์ ์„ : 1.0 = ํ•œ๊ณ„์†Œ์š” ์ •์ฐฉ๊ธธ์ด ๋Œ€ ํ™•๋ณด ๋ฌปํž˜๊ธธ์ด1.0 ์ดํ•˜๋ฉด ๋งŒ์กฑ0.56RC2.00KDS 141.86KDS 241.86ACI 152.00ACI 221.86AASHTO์ง์„  ์ •์ฐฉ ld [mm]- - ์ ์„ : ํ™•๋ณด = 1,200๊ฐˆ๊ณ ๋ฆฌ ์—†์ด ๊ณง๊ฒŒ ๋ฌป์–ด ํž˜์„ ์ „๋‹ฌํ•˜๋Š” ๋ฐ ํ•„์š”ํ•œ ๊ธธ์ด668RC2,400KDS 142,228KDS 242,228ACI 152,400ACI 222,228AASHTO๋ง‰๋Œ€๊ฐ€ ์ ์„  ์•„๋ž˜๋ฉด OKํ‘œ์ค€๊ฐˆ๊ณ ๋ฆฌ ldh [mm]- - ์ ์„ : ํ™•๋ณด = 1,20090ยฐ ๊ตฝํ˜€ ์ •์ฐฉํ•  ๋•Œ ํ•„์š”ํ•œ ๊ธธ์ด์ง์„ ๋ณด๋‹ค ์งง์Œ312RC890KDS 14838KDS 24838ACI 15890ACI 221,197AASHTO๋ง‰๋Œ€๊ฐ€ ์ ์„  ์•„๋ž˜๋ฉด OK๊ฒน์นจ์ด์Œ [mm]- - ์ ์„ : ํ™•๋ณด = 1,200๋‘ ๋ณด๊ฐ•๊ทผ์„ ๊ฒน์ณ ํž˜์„ ๋„˜๊ธฐ๋Š” ๋ฐ ํ•„์š”ํ•œ ๊ธธ์ด868RC3,121KDS 142,896KDS 242,896ACI 153,121ACI 222,896AASHTOld / db์ •์ฐฉ๊ธธ์ด๋ฅผ ์ง€๋ฆ„์œผ๋กœ ๋‚˜๋ˆˆ ๊ฐ’๊ธฐ์ค€๋ผ๋ฆฌ ๋ฐ”๋กœ ๊ฒฌ์ค„ ์ˆ˜ ์žˆ์Œ26RC95KDS 1488KDS 2488ACI 1595ACI 2288AASHTO์„ค๊ณ„์ธ์žฅ๊ฐ•๋„ ffr [MPa]ํ™˜๊ฒฝ๊ฐ์†Œ๊ณ„์ˆ˜๋ฅผ ๊ณฑํ•ด ์ •์ฐฉ ๊ณ„์‚ฐ์— ์“ฐ๋Š” ๊ฐ•๋„400RC850KDS 14800KDS 24800ACI 15850ACI 22800AASHTO
ํ•ญ๋ชฉRC, KDS 14 20 52KDS 14 20 68KDS 24 50 05ACI 440.1R-15ACI 440.11-22AASHTO GFRP 2018
์˜ˆ์ œ ๊ฒฐ๊ณผ
G25.4, ํ™•๋ณด 1200 mm
$\text{์†Œ์š” }l_d = \boxed{\mathbf{668}\ \text{mm}}$
$\text{ํ™•๋ณด }1200\ \to\ 0.56\ \ \color{#0a8a2a}{\checkmark\ \textbf{OK}}$
$l_d$ = 668, $l_{dh}$ = 312, ์ด์Œ = 868 mm
$\text{์†Œ์š” }l_d = \boxed{\mathbf{2{,}400}\ \text{mm}}$
$\text{ํ™•๋ณด }1200\ \to\ 2.00\ \ \color{#d40000}{\times\ \textbf{NG}}$
$l_d$ = 2400, $l_{dh}$ = 890, ์ด์Œ = 3121 mm
$\text{์†Œ์š” }l_d = \boxed{\mathbf{2{,}228}\ \text{mm}}$
$\text{ํ™•๋ณด }1200\ \to\ 1.86\ \ \color{#d40000}{\times\ \textbf{NG}}$
$l_d$ = 2228, $l_{dh}$ = 838, ์ด์Œ = 2896 mm
$\text{์†Œ์š” }l_d = \boxed{\mathbf{2{,}228}\ \text{mm}}$
$\text{ํ™•๋ณด }1200\ \to\ 1.86\ \ \color{#d40000}{\times\ \textbf{NG}}$
$l_d$ = 2228, $l_{dh}$ = 838, ์ด์Œ = 2896 mm
$\text{์†Œ์š” }l_d = \boxed{\mathbf{2{,}400}\ \text{mm}}$
$\text{ํ™•๋ณด }1200\ \to\ 2.00\ \ \color{#d40000}{\times\ \textbf{NG}}$
$l_d$ = 2400, $l_{dh}$ = 890, ์ด์Œ = 3121 mm
$\text{์†Œ์š” }l_d = \boxed{\mathbf{2{,}228}\ \text{mm}}$
$\text{ํ™•๋ณด }1200\ \to\ 1.86\ \ \color{#d40000}{\times\ \textbf{NG}}$
$l_d$ = 2228, $l_{dh}$ = 1197, ์ด์Œ = 2896 mm
์ •์ฐฉ ์›์น™
์ตœ์†Ÿ๊ฐ’
$$ l_d\ge300\ \text{mm} $$
๋ฌปํž˜๊ธธ์ด
๊ฐˆ๊ณ ๋ฆฌ
๊ธฐ๊ณ„์  ์ •์ฐฉ์˜ ์กฐํ•ฉ
๊ฐˆ๊ณ ๋ฆฌ๋Š” ์••์ถ•์ฒ ๊ทผ ์ •์ฐฉ์— ๋ฌดํšจ
$$ l_d\ge\max\big(\text{์‹ }(4.7\text{-}1),\ 20d_b,\ 300\big) $$
๊ฐˆ๊ณ ๋ฆฌ๋Š” ์ธ์žฅ ์˜์—ญ ๋ณด๊ฐ•๊ทผ์—๋งŒ ์œ ํšจ (4.7.1.1(2))
$$ l_d\ge\max\big(\text{์‹ }(8.1\text{-}3),\ 20d_b\big) $$
๊ฐˆ๊ณ ๋ฆฌ
๋‹จ๋ถ€ ํ™•๋Œ€๋จธ๋ฆฌ๋Š” ์ธ์žฅ ์˜์—ญ์—๋งŒ (8.1(2))
mm ์ตœ์†Ÿ๊ฐ’ ์—†์Œ
$$ l_d:\ (10.3a),\qquad \ge20d_b\ \text{(๊ถŒ๊ณ )} $$
20d_b ๋ฏธ๋งŒ ๋ฌปํž˜ ๋น„๊ถŒ์žฅ
100d_b ์ดˆ๊ณผ ์ž๋ฃŒ ์—†์Œ (10.1)
$$ l_d\ge\max\big(\text{(25.4.2.4)},\ 20d_b,\ 12\text{ in}\big) $$
ฯ† ๋ฏธ์ ์šฉ (25.4.1.3)
โˆšfโ€ฒc โ‰ค 100 psi (25.4.1.4)
$$ l_d\ge\max\big(\text{(2.9.7.4.1-1)},\ 20d_b\big) $$
๋‹จ๋ถ€ ์ •์ฐฉ์žฅ์น˜๋Š” ASTM D3916 ์ƒ๋‹น ์‹œํ—˜์œผ๋กœ ์„ฑ๋Šฅ ์ž…์ฆ (2.9.7.2)
์ง์„  ์ธ์žฅ ์ •์ฐฉ๊ธธ์ด
$l_d$
4.1.2(3) (4.1-2)
$$ l_d=\frac{0.90\,d_b\,f_y}{\lambda\sqrt{f_{ck}}}\cdot\frac{\alpha\beta\gamma}{\left(\dfrac{c+K_{tr}}{d_b}\right)} $$
$(c+K_{tr})/d_b\le2.5$
์•ฝ์‚ฐ์‹ (4.1-1) $l_{db}=0.6d_b\,f_y/(\lambda\sqrt{f_{ck}})$ ร— ํ‘œ 4.1-1 ๋„ ํ—ˆ์šฉ
$$\begin{aligned}l_d &= \frac{0.90\,d_b\,f_y}{\lambda\sqrt{f_{ck}}}\cdot\frac{\alpha\beta\gamma}{(c+K_{tr})/d_b} = \frac{0.90\times25.4\times400}{1.0\sqrt{30}}\times\frac{1\times1\times1}{2.50} \\ &= \boxed{\mathbf{668}\ \text{mm}}\ (26.3d_b) \\ \text{์•ฝ์‚ฐ์‹ }l_{db} &= \frac{0.6\times25.4\times400}{\sqrt{30}} = 1113\ \to\ 1113\ /\ 1669\end{aligned}$$
4.7.1.2(1) (4.7-1)
$$ l_d=\frac{d_b\left(\dfrac{f_{fr}}{0.083\sqrt{f_{ck}}}-340\right)\psi_t}{13.6+\dfrac{c_b}{d_b}} $$
$f_{fr}$ = ์š”๊ตฌ๋˜๋Š” ๋ณด๊ฐ•๊ทผ ์‘๋ ฅ
$c_b/d_b\le3.5$
$\psi_t$ ๋Š” ๊ด„ํ˜ธ ๋ฐ– (ACI 440.11 ๊ณ„๋ณด)
$$\begin{aligned}c_b &= \min(c+d_{bv}+d_b/2,\ s/2) = \min(65.7,\ 67.2) = 65.7 \\ c_b/d_b &= \min(2.59,\,3.5) = 2.59 \\ l_d &= \frac{d_b\left(\dfrac{f_{fr}}{0.083\sqrt{f_{ck}}}-340\right)\psi_t}{13.6+c_b/d_b} = \frac{25.4\left(\dfrac{850}{0.083\sqrt{30}}-340\right)\times1}{13.6+2.59} \\ &= \boxed{\mathbf{2{,}400}\ \text{mm}}\ (94.5d_b)\end{aligned}$$
8.1.2(1) (8.1-3)
$$ l_d=\frac{\alpha\dfrac{f_{fr}}{0.083\sqrt{f_{ck}}}-340}{13.6+\dfrac{C}{d_b}}\,d_b $$
$f_{fr}=\min\big(f_f\ (5.2\text{-}1),\ f_{fe}\ (8.1\text{-}2)\big)$
$\alpha$ ๋Š” ๋ถ„์ž ์•ˆ (AASHTO ๊ณ„๋ณด)
$$\begin{aligned}c_b &= \min(c+d_{bv}+d_b/2,\ s/2) = \min(65.7,\ 67.2) = 65.7 \\ c_b/d_b &= \min(2.59,\,3.5) = 2.59 \\ l_d &= \frac{\alpha\dfrac{f_{fr}}{0.083\sqrt{f_{ck}}}-340}{13.6+C/d_b}\,d_b = \frac{1\times\dfrac{800}{0.083\sqrt{30}}-340}{13.6+2.59}\times25.4 \\ &= \boxed{\mathbf{2{,}228}\ \text{mm}}\ (87.7d_b)\end{aligned}$$
10.3 (10.3a)
$$ l_d=\frac{\alpha\dfrac{f_{fr}}{0.083\sqrt{f'_c}}-340}{13.6+\dfrac{C}{d_b}}\,d_b $$
$f_{fr}=\min\big(f_{fu},\ (7.2.2d),\ (10.1c)\big)$
์˜ˆ์ œ 9M
10M ์œผ๋กœ ฮฑ ์œ„์น˜ ํ™•์ธ
$$\begin{aligned}c_b &= \min(c+d_{bv}+d_b/2,\ s/2) = \min(65.7,\ 67.2) = 65.7 \\ c_b/d_b &= \min(2.59,\,3.5) = 2.59 \\ l_d &= \frac{\alpha\dfrac{f_{fr}}{0.083\sqrt{f_{ck}}}-340}{13.6+C/d_b}\,d_b = \frac{1\times\dfrac{800}{0.083\sqrt{30}}-340}{13.6+2.59}\times25.4 \\ &= \boxed{\mathbf{2{,}228}\ \text{mm}}\ (87.7d_b)\end{aligned}$$
25.4.2.4 (25.4.2.4)
$$ l_d=\frac{d_b\left(\dfrac{f_{fr}}{\sqrt{f'_c}}-340\right)\psi_t}{13.6+\dfrac{c_b}{d_b}}\ [\text{psi}] $$
SI: $f_{fr}/(0.083\sqrt{f_{ck}})$
KDS 14 20 68 (4.7-1) ๊ณผ ๋™์ผ
$$\begin{aligned}c_b &= \min(c+d_{bv}+d_b/2,\ s/2) = \min(65.7,\ 67.2) = 65.7 \\ c_b/d_b &= \min(2.59,\,3.5) = 2.59 \\ l_d &= \frac{d_b\left(\dfrac{f_{fr}}{0.083\sqrt{f_{ck}}}-340\right)\psi_t}{13.6+c_b/d_b} = \frac{25.4\left(\dfrac{850}{0.083\sqrt{30}}-340\right)\times1}{13.6+2.59} \\ &= \boxed{\mathbf{2{,}400}\ \text{mm}}\ (94.5d_b)\end{aligned}$$
2.9.7.4.1 (2.9.7.4.1-1)
$$ l_d\ge\max\!\left(\frac{31.6\,\alpha\dfrac{f_{fr}}{\sqrt{f'_c}}-340}{13.6+\dfrac{C}{d_b}}\,d_b,\ 20d_b\right)\ [\text{ksi}] $$
$31.6/\sqrt{\text{ksi}}=1/(0.083\sqrt{\text{MPa}})$ โ†’ SI ๋™์ผ์‹
$$\begin{aligned}c_b &= \min(c+d_{bv}+d_b/2,\ s/2) = \min(65.7,\ 67.2) = 65.7 \\ c_b/d_b &= \min(2.59,\,3.5) = 2.59 \\ l_d &= \frac{\alpha\dfrac{f_{fr}}{0.083\sqrt{f_{ck}}}-340}{13.6+C/d_b}\,d_b = \frac{1\times\dfrac{800}{0.083\sqrt{30}}-340}{13.6+2.59}\times25.4 \\ &= \boxed{\mathbf{2{,}228}\ \text{mm}}\ (87.7d_b)\end{aligned}$$
๋ณด์ •๊ณ„์ˆ˜
ํ”ผ๋ณต๋น„
4.1.2(2)(3) ํ‘œ 4.1-1
$$ \alpha=1.3\ (\text{์ƒ๋ถ€๊ทผ}),\ \ \beta=1.5/1.2/1.0\ (\text{์—ํญ์‹œ}),\ \alpha\beta\le1.7,\ \ \gamma=0.8\ (\le\text{D19})/1.0,\ \ K_{tr}=\frac{40A_{tr}}{sn} $$
$c$ = ์ฒ ๊ทผ ์ค‘์‹ฌโ€“ํ‘œ๋ฉด ์ตœ๋‹จ๊ฑฐ๋ฆฌ์™€ ์ค‘์‹ฌ๊ฐ„๊ฒฉ/2 ์ค‘ ์ž‘์€ ๊ฐ’
๊ฐ„ํŽธํžˆ $K_{tr}=0$
$$\begin{aligned}\alpha &= 1\ (์ผ๋ฐ˜),\quad \beta = 1,\quad \gamma = 1\ (D22 ์ด์ƒ) \\ c &= \min(65.7,\ 67.2) = 65.7 \\ \frac{c+K_{tr}}{d_b} &= \min\!\left(\frac{65.7+0}{25.4},\,2.5\right) = 2.50\end{aligned}$$
$$ \psi_t=1.5\ (\text{์•„๋ž˜ }300\text{ mm ์ดˆ๊ณผ ํƒ€์„ค})\ /\ 1.0,\qquad \frac{c_b}{d_b}\le3.5 $$
$c_b$ = ๋ณด๊ฐ•๊ทผ ์ค‘์‹ฌโ€“์ฝ˜ํฌ๋ฆฌํŠธ ์™ธ์ธก ๊ฑฐ๋ฆฌ์™€ ์ค‘์‹ฌ ๊ฐ„๊ฒฉ/2 ์ค‘ ์ž‘์€ ๊ฐ’
$$\begin{aligned}\psi_t &= 1\ (์ผ๋ฐ˜) \\ c_b/d_b &= 2.59\ (\le3.5)\end{aligned}$$
$$ \alpha=1.5\ (\text{์ƒ๋ถ€, }300\text{ mm ์ดˆ๊ณผ})\ /\ 1.0,\qquad \frac{C}{d_b}\le3.5 $$
$$\begin{aligned}\alpha &= 1\ (์ผ๋ฐ˜) \\ c_b/d_b &= 2.59\ (\le3.5)\end{aligned}$$
$$ \alpha=1.5\ (>12\text{ in ์•„๋ž˜ ํƒ€์„ค})\ /\ 1.0,\qquad \frac{C}{d_b}\le3.5 $$
์žฌ๋ฃŒ๊ณ„์ˆ˜: AFRP
CFRP ๋„ 1.0 (10.1.2)
$$\begin{aligned}\alpha &= 1\ (์ผ๋ฐ˜) \\ c_b/d_b &= 2.59\ (\le3.5)\end{aligned}$$
$$ \psi_t=1.5\ (>12\text{ in})\ /\ 1.0,\qquad \frac{c_b}{d_b}\le3.5 $$
$$\begin{aligned}\psi_t &= 1\ (์ผ๋ฐ˜) \\ c_b/d_b &= 2.59\ (\le3.5)\end{aligned}$$
$$ \alpha=1.5\ (>12\text{ in})\ /\ 1.0,\qquad \frac{C}{d_b}\le3.5 $$
$$\begin{aligned}\alpha &= 1\ (์ผ๋ฐ˜) \\ c_b/d_b &= 2.59\ (\le3.5)\end{aligned}$$
๋ถ€์ฐฉ์‘๋ ฅ $u$
์ •์ฐฉ์‘๋ ฅ $f_{fe}$ (๋ฌปํž˜ $l_e$)
ํ•ด๋‹น ์—†์Œ
RC ํ•ด๋‹น ์—†์Œ (์ •์ฐฉ๊ธธ์ด ์‹์œผ๋กœ๋งŒ)
ํ•ด๋‹น ์—†์Œ
๊ทœ์ • ์—†์Œ (์ •์ฐฉ๊ธธ์ด ์‹์œผ๋กœ๋งŒ)
8.1.1(1)(3) (8.1-1)(8.1-2)
$$ u=0.083\sqrt{f_{ck}}\left(4.0+0.3\frac{C}{d_b}+100\frac{d_b}{l_e}\right),\qquad f_{fe}=\frac{0.083\sqrt{f_{ck}}}{\alpha}\left(13.6\frac{l_e}{d_b}+\frac{C}{d_b}\frac{l_e}{d_b}+340\right)\le f_{fu} $$
ํ™•๋ณด ๋ฌปํž˜๊ธธ์ด $l_e$ ์—์„œ ๋ฐœํœ˜ ๊ฐ€๋Šฅํ•œ ์‘๋ ฅ โ†’ $f_{fr}$ ์ƒํ•œ
$$\begin{aligned}l_e &= 1200\ \text{mm (ํ™•๋ณด)} \\ u &= 0.083\sqrt{30}\left(4.0+0.3\times2.59+100\times\frac{25.4}{1200}\right) = 3.13\ \text{MPa} \\ f_{fe} &= \frac{0.083\sqrt{30}}{1}\left(13.6\times47.2+2.59\times47.2+340\right) = 502\ \to\ \min(f_{fe},f_{fu}) = \boxed{\mathbf{502}\ \text{MPa}}\end{aligned}$$
10.1 (10.1b)(10.1c)
$$ u=0.083\sqrt{f'_c}\left(4.0+0.3\frac{C}{d_b}+100\frac{d_b}{l_e}\right),\qquad f_{fe}=\frac{0.083\sqrt{f'_c}}{\alpha}\left(13.6\frac{l_e}{d_b}+\frac{C}{d_b}\frac{l_e}{d_b}+340\right)\le f_{fu} $$
Wambeke & Shield(2006) 269 ์‹คํ—˜ ํšŒ๊ท€
์ฒซ $20d_b$ ๊ตฌ๊ฐ„์€ ์„ ํ˜• ์ฆ๊ฐ€ ๊ฐ€์ •
$$\begin{aligned}l_e &= 1200\ \text{mm (ํ™•๋ณด)} \\ u &= 0.083\sqrt{30}\left(4.0+0.3\times2.59+100\times\frac{25.4}{1200}\right) = 3.13\ \text{MPa} \\ f_{fe} &= \frac{0.083\sqrt{30}}{1}\left(13.6\times47.2+2.59\times47.2+340\right) = 502\ \to\ \min(f_{fe},f_{fu}) = \boxed{\mathbf{502}\ \text{MPa}}\end{aligned}$$
ํ•ด๋‹น ์—†์Œ
๊ทœ์ • ์—†์Œ (์ •์ฐฉ๊ธธ์ด ์‹์œผ๋กœ๋งŒ)
ํ•ด๋‹น ์—†์Œ
๊ทœ์ • ์—†์Œ (์ •์ฐฉ๊ธธ์ด ์‹์œผ๋กœ๋งŒ)
์†Œ์š”/๋ฐฐ๊ทผ ๊ฐ์†Œ
์ตœ์ข… $l_d$
$$ l_d\times\frac{A_{s,req}}{A_{s,prov}}\ \ge300\ \text{mm} $$
$f_y$ ๋ฐœํœ˜๋ฅผ ํŠน๋ณ„ํžˆ ์š”๊ตฌํ•˜๋Š” ๊ฒฝ์šฐ ๋ฏธ์ ์šฉ
$$\begin{aligned}l_d &= \max(668\times1,\ 300) = \boxed{\mathbf{668}\ \text{mm}}\ (26.3d_b)\end{aligned}$$
$$ l_d\times\frac{A_{f,req}}{A_{f,prov}}\ \ge\max(20d_b,\ 300) $$
$f_{fu}$ ๋ฐœํœ˜ ์š”๊ตฌ
์—ฐ์†
๊ธฐ๊ณ„์  ์ •์ฐฉ ์‹œ ๋ฏธ์ ์šฉ
$$\begin{aligned}l_d &= \max(2400\times1,\ 20d_b = 508,\ 300) = \boxed{\mathbf{2{,}400}\ \text{mm}}\ (94.5d_b)\end{aligned}$$
$$ l_d\times\frac{A_{f,req}}{A_{f,prov}} $$
๋ฐ›์นจ๋ถ€ ์ •๋ชจ๋ฉ˜ํŠธ
์˜จ๋„์ˆ˜์ถ• ๋ณด๊ฐ•๊ทผ ๋“ฑ ์„ค๊ณ„์ธ์žฅ๊ฐ•๋„ ์ •์ฐฉ ์š”๊ตฌ ์œ„์น˜์—” ๋ฏธ์ ์šฉ
$$\begin{aligned}l_d &= \max(2228\times1,\ 20d_b = 508) = \boxed{\mathbf{2{,}228}\ \text{mm}}\ (87.7d_b)\end{aligned}$$
$$ f_{fr}\ (\text{์š”๊ตฌ ์‘๋ ฅ})\text{๋กœ ์ง์ ‘ ๋ฐ˜์˜} $$
๋ฉด์ ๋น„ ๋Œ€์‹  ์š”๊ตฌ ์‘๋ ฅ $f_{fr}$ ์„ ๋‚ฎ์ถฐ ๋ฐ˜์˜
$$\begin{aligned}l_d &= \max(2228\times1,\ 20d_b = 508) = \boxed{\mathbf{2{,}228}\ \text{mm}}\ (87.7d_b)\end{aligned}$$
$$ l_d\times\frac{A_{f,req}}{A_{f,prov}}\ \ge\max(20d_b,\ 12\text{ in}) $$
$f_{fu}$ ์ •์ฐฉ ์š”๊ตฌ
์—ฐ์†
๊ธฐ๊ณ„์  ์ •์ฐฉ์—๋Š” ๊ธˆ์ง€ (25.4.10.2)
$$\begin{aligned}l_d &= \max(2400\times1,\ 20d_b = 508,\ 300) = \boxed{\mathbf{2{,}400}\ \text{mm}}\ (94.5d_b)\end{aligned}$$
$$ f_{fr}\ (\text{์š”๊ตฌ ์‘๋ ฅ})\text{๋กœ ์ง์ ‘ ๋ฐ˜์˜} $$
๋ฉด์ ๋น„ ๊ทœ์ • ์—†์Œ
$$\begin{aligned}l_d &= \max(2228\times1,\ 20d_b = 508) = \boxed{\mathbf{2{,}228}\ \text{mm}}\ (87.7d_b)\end{aligned}$$
์••์ถ• ์ •์ฐฉ
4.1.3 (4.1-3)
$$ l_{db}=\frac{0.25d_b\,f_y}{\lambda\sqrt{f_{ck}}}\ge0.043d_b\,f_y,\qquad l_d\ge200 $$
ร—(์†Œ์š”/๋ฐฐ๊ทผ)
ร—0.75 (D13 ๋ 
๋‚˜์„  ๊ตฌ์†)
$$\begin{aligned}l_{db} &= \max\!\left(\frac{0.25\times25.4\times400}{\sqrt{30}},\ 0.043\times25.4\times400\right) = 464 \\ l_d &= \max(464,\ 200) = \boxed{\mathbf{464}\ \text{mm}}\end{aligned}$$
$$ l_{d,c}=l_d\ \big(4.7.1.2(1)\big) $$
์ธ์žฅ ์ •์ฐฉ์‹ ์ค€์šฉ
$$\begin{aligned}l_{d,c} &= l_d = \boxed{\mathbf{2{,}400}\ \text{mm}}\end{aligned}$$
ํ•ด๋‹น ์—†์Œ
๊ทœ์ • ์—†์Œ (์••์ถ• ๋ณด๊ฐ•๊ทผ ๊ฐ•๋„ ๋ฌด์‹œ)
ํ•ด๋‹น ์—†์Œ
๊ทœ์ • ์—†์Œ (์••์ถ• FRP ๋ฌด์‹œ 7.2.5.3)
$$ l_{dc}=l_d\ (25.4.2) $$
์‹คํ—˜์ž๋ฃŒ ์—†์Œ โ†’ ์ธ์žฅ์‹ (๋ณด์ˆ˜์ )
$$\begin{aligned}l_{d,c} &= l_d = \boxed{\mathbf{2{,}400}\ \text{mm}}\end{aligned}$$
์••์ถ•๋ถ€์žฌ ์ถ”๊ฐ€ ๊ฐ•๋„์šฉ GFRP ์‚ฌ์šฉ ๋ถˆ๊ฐ€ (1.3)
ํ‘œ์ค€๊ฐˆ๊ณ ๋ฆฌ
$l_{dh}$
4.1.5 (4.1-4)
$$ l_{hb}=\frac{0.24\beta d_b\,f_y}{\lambda\sqrt{f_{ck}}},\qquad l_{dh}\ge\max(8d_b,\ 150) $$
ร—0.7 (D35 ์ดํ•˜
์ธก๋ฉดํ”ผ๋ณต โ‰ฅ 70
๊ฐˆ๊ณ ๋ฆฌ ๋„˜์–ด์„  ํ”ผ๋ณต โ‰ฅ 50)
ร—0.8 (๋ ์ฒ ๊ทผ $3d_b$)
ร—(์†Œ์š”/๋ฐฐ๊ทผ)
$$\begin{aligned}l_{hb} &= \frac{0.24\times1\times25.4\times400}{\sqrt{30}} = 445 \\ l_{dh} &= \max(445\times0.70,\ 8d_b = 203,\ 150) = \boxed{\mathbf{312}\ \text{mm}}\ (\text{๊ผฌ๋ฆฌ }12d_b = 305)\end{aligned}$$
4.7.1.5 (4.7-2)
$$ l_{dh}=\begin{cases}165\,d_b/\sqrt{f_{ck}} & f_{fu}\le520\\ f_{fu}d_b/(3.1\sqrt{f_{ck}}) & 520\lt f_{fu}\lt1{,}040\\ 330\,d_b/\sqrt{f_{ck}} & f_{fu}\ge1{,}040\end{cases}\ \ \ge\max(12d_b,\ 230) $$
ร—0.7 (์ธก๋ฉดํ”ผ๋ณต > 65
๋„˜์–ด์„  ํ”ผ๋ณต โ‰ฅ 50)
90ยฐ ๊ฐˆ๊ณ ๋ฆฌ๋งŒ (4.6.1.1)
$$\begin{aligned}f_{fu} &= 850\ \text{MPa}\ \to\ \text{๊ตฌ๊ฐ„ }520 < f_{fu} < 1040 \\ l_{bhf} &= 850\times25.4/(3.1\sqrt{30}) = 1272 \\ l_{dh} &= \max(1272\times0.7,\ 12d_b = 305,\ 230) = \boxed{\mathbf{890}\ \text{mm}}\ (\text{๊ผฌ๋ฆฌ }12d_b,\ r\ge3d_b = 76)\end{aligned}$$
8.1.3 (8.1-5)
$$ l_{bdf}=\begin{cases}165\,d_b/\sqrt{f_{ck}} & f_{fu}\le520\\ f_{fu}d_b/(3.1\sqrt{f_{ck}}) & 520\lt f_{fu}\lt1{,}030\\ 330\,d_b/\sqrt{f_{ck}} & f_{fu}\ge1{,}030\end{cases}\ \ \ge\max(12d_b,\ 230) $$
๊ตฝํž˜ ๋ฐ˜์ง€๋ฆ„ โ‰ฅ $3d_b$
๊ผฌ๋ฆฌ โ‰ฅ $12d_b$
ร—0.7 (์ธก๋ฉด โ‰ฅ 64
๋„˜์–ด์„  โ‰ฅ 50)
$$\begin{aligned}f_{fu} &= 800\ \text{MPa}\ \to\ \text{๊ตฌ๊ฐ„ }520 < f_{fu} < 1030 \\ l_{bhf} &= 800\times25.4/(3.1\sqrt{30}) = 1197 \\ l_{dh} &= \max(1197\times0.7,\ 12d_b = 305,\ 230) = \boxed{\mathbf{838}\ \text{mm}}\ (\text{๊ผฌ๋ฆฌ }12d_b,\ r\ge3d_b = 76)\end{aligned}$$
10.2 (10.2b)
$$ l_{bhf}=\begin{cases}165\,d_b/\sqrt{f'_c} & f_{fu}\le520\\ f_{fu}d_b/(3.1\sqrt{f'_c}) & 520\lt f_{fu}\lt1{,}040\\ 330\,d_b/\sqrt{f'_c} & f_{fu}\ge1{,}040\end{cases}\ \ \ge\max(12d_b,\ 230) $$
Ehsani(1996) 36 ์‹คํ—˜
๊ผฌ๋ฆฌ $12d_b$
$r\ge3d_b$
ร—0.7 (64/50)
$$\begin{aligned}f_{fu} &= 800\ \text{MPa}\ \to\ \text{๊ตฌ๊ฐ„ }520 < f_{fu} < 1040 \\ l_{bhf} &= 800\times25.4/(3.1\sqrt{30}) = 1197 \\ l_{dh} &= \max(1197\times0.7,\ 12d_b = 305,\ 230) = \boxed{\mathbf{838}\ \text{mm}}\ (\text{๊ผฌ๋ฆฌ }12d_b,\ r\ge3d_b = 76)\end{aligned}$$
$$ l_{dh}=\begin{cases}2000\,d_b/\sqrt{f'_c} & f_{fu}\le75\text{ ksi}\\ f_{fu}d_b/(37.5\sqrt{f'_c}) & 75\lt f_{fu}\lt150\\ 4000\,d_b/\sqrt{f'_c} & \ge150\end{cases}\ \ \ge\max(12d_b,\ 9\text{ in}) $$
SI 165/3.1/330
ร—0.7 (2.5 in / 2 in)
ํ‘œ 25.3.1 ๊ผฌ๋ฆฌ $12d_b$
$$\begin{aligned}f_{fu} &= 850\ \text{MPa}\ \to\ \text{๊ตฌ๊ฐ„ }520 < f_{fu} < 1040 \\ l_{bhf} &= 850\times25.4/(3.1\sqrt{30}) = 1272 \\ l_{dh} &= \max(1272\times0.7,\ 12d_b = 305,\ 230) = \boxed{\mathbf{890}\ \text{mm}}\ (\text{๊ผฌ๋ฆฌ }12d_b,\ r\ge3d_b = 76)\end{aligned}$$
2.9.7.4.3 (2.9.7.4.3-1)
$$ l_{dh}=\begin{cases}63.2\,d_b/\sqrt{f'_c} & f_{fd}\le75\text{ ksi}\\ f_{fd}d_b/(1.2\sqrt{f'_c}) & 75\lt f_{fd}\lt150\\ 126.4\,d_b/\sqrt{f'_c} & \ge150\end{cases}\ \ \ge\max(12d_b,\ 9\text{ in}) $$
ksi โ†’ SI 165/3.1/330 (์„ค๊ณ„๊ฐ•๋„ $f_{fd}$)
ํ”ผ๋ณต 0.7 ๊ฐ์†Œ ๊ทœ์ • ์—†์Œ (2026-08-30 ์›๋ฌธ ๋Œ€์กฐ๋กœ ์ˆ˜์ •)
$$\begin{aligned}f_{fu} &= 800\ \text{MPa}\ \to\ \text{๊ตฌ๊ฐ„ }520 < f_{fu} < 1030 \\ l_{bhf} &= 800\times25.4/(3.1\sqrt{30}) = 1197 \\ l_{dh} &= \max(1197\times1,\ 12d_b = 305,\ 230) = \boxed{\mathbf{1{,}197}\ \text{mm}}\ (\text{๊ผฌ๋ฆฌ }12d_b,\ r\ge3d_b = 76)\end{aligned}$$
ํ™•๋Œ€๋จธ๋ฆฌ
๊ธฐ๊ณ„์  ์ •์ฐฉ
4.1.6 (4.1-5)(4.1-6)(4.1-7)
$$ l_{dt}=\frac{0.22\beta d_b\,f_y}{\psi\sqrt{f_{ck}}}\ (\text{์ ‘ํ•ฉ๋ถ€}),\ \ \psi=0.6+0.3\frac{c_{so}}{d_b}+0.38\frac{K_{tr}}{d_b}\le1.375;\qquad l_{dt}=\frac{0.24\beta d_b\,f_y}{\sqrt{f_{ck}}}\ (\text{๊ทธ ์™ธ})\ \ \ge\max(8d_b,150) $$
์ˆœ์ง€์••๋ฉด์  โ‰ฅ $4A_b$
๋ณดํ†ต์ค‘๋Ÿ‰์ฝ˜ํฌ๋ฆฌํŠธ๋งŒ
์••์ถ•์—” ๋ฌดํšจ
$$\begin{aligned}l_{dt} &= \frac{0.24\times1\times25.4\times400}{\sqrt{30}} = 445\ \to\ \max(\cdot,\ 8d_b,\ 150) = \boxed{\mathbf{445}\ \text{mm}}\ (\text{๊ทธ ์™ธ ๋ถ€์œ„ (4.1-7)})\end{aligned}$$
ํ™•๋Œ€๋จธ๋ฆฌ: ๊ทœ์ • ์—†์Œ
๊ธฐ๊ณ„์ ์ด์Œ์€ $1.25f_{fu}$ ์ด์ƒ (4.7.3.1(3))
โ†— 4.7.3.1(3)
ํ™•๋Œ€๋จธ๋ฆฌ ์ •์ฐฉ: 8.1.6 (์ œ์กฐ์‚ฌ ์„ฑ๋Šฅ ์‹œํ—˜)
ํ•ด๋‹น ์—†์Œ
๊ทœ์ • ์—†์Œ
$$ \text{๊ธฐ๊ณ„์  ์ •์ฐฉ: }1.25f_{fu}\ \text{๋ฐœํœ˜} $$
ํ™•๋Œ€๋จธ๋ฆฌ(headed) ๋ฒ”์œ„ ๋ฐ–
๊ธฐ๊ณ„์  ์ •์ฐฉ์€ 1.10 ์Šน์ธ + ASTM D7957 ๋‚ด๊ตฌ์„ฑ
๊ธฐ๊ณ„์  ์ •์ฐฉ: ์‹คํ—˜์œผ๋กœ ์„ฑ๋Šฅ ๊ฒ€์ฆ
๊ณ„์•ฝ๋„์„œ ๋ช…์‹œ
๊ฒน์นจ์ด์Œ (์ธ์žฅ)
$$ \text{A๊ธ‰ }1.0l_d,\qquad \text{B๊ธ‰ }1.3l_d\ \ (\ge300) $$
$l_d$ = 4.1.2 (300 ์ตœ์†Ÿ๊ฐ’
(4) ๊ฐ์†Œ ๋ฏธ์ ์šฉ)
A๊ธ‰ = ๋ฐฐ๊ทผ โ‰ฅ 2ร—์†Œ์š” & ์ด์Œ โ‰ค 1/2
$$\begin{aligned}l_d^{(4.5.2)} &= 668\ (\text{300 ์ตœ์†Ÿ๊ฐ’ ๋ฐ ๊ฐ์†Œ ๋ฏธ์ ์šฉ}) \\ l_{lap} &= \max(1.3\times668,\ 300) = \boxed{\mathbf{868}\ \text{mm}}\ (B๊ธ‰)\end{aligned}$$
$$ \text{A๊ธ‰ }1.0l_d,\qquad \text{B๊ธ‰ }1.3l_d\ \ \ge\max(20d_b,\ 300) $$
G32 ์ด์ƒ ๊ฒน์นจ์ด์Œ ๋ถˆ๊ฐ€ (4.7.3.1(2))
$l_d$ ๋Š” 300 ์ตœ์†Ÿ๊ฐ’
๋ณด์ •๊ณ„์ˆ˜ ๋ฏธ์ ์šฉ
$$\begin{aligned}l_d(f_{fu}) &= 2400\ (\text{์ตœ์†Ÿ๊ฐ’ ๋ฐ ๊ฐ์†Œ ๋ฏธ์ ์šฉ}) \\ l_{lap} &= \max(1.3\times2400,\ 20d_b = 508,\ 300) = \boxed{\mathbf{3{,}121}\ \text{mm}}\ (B๊ธ‰)\end{aligned}$$
$$ l_{lap}\ge1.3l_d\ (\text{๋ชจ๋“  ๊ฒฝ์šฐ}) $$
$$\begin{aligned}l_d(f_{fu}) &= 2228\ (\text{์ตœ์†Ÿ๊ฐ’ ๋ฐ ๊ฐ์†Œ ๋ฏธ์ ์šฉ}) \\ l_{lap} &= \max(1.3\times2228,\ 20d_b = 508) = \boxed{\mathbf{2{,}896}\ \text{mm}}\ (๋ชจ๋“  ๊ฒฝ์šฐ)\end{aligned}$$
$$ l_{lap}=1.3l_d\ (\text{๋ชจ๋“  ๊ฒฝ์šฐ}) $$
A/B ๊ตฌ๋ถ„ ์—†์Œ (๋ณด์ˆ˜์ )
$$\begin{aligned}l_d(f_{fu}) &= 2228\ (\text{์ตœ์†Ÿ๊ฐ’ ๋ฐ ๊ฐ์†Œ ๋ฏธ์ ์šฉ}) \\ l_{lap} &= \max(1.3\times2228,\ 20d_b = 508) = \boxed{\mathbf{2{,}896}\ \text{mm}}\ (๋ชจ๋“  ๊ฒฝ์šฐ)\end{aligned}$$
$$ \text{Class A }1.0l_d,\qquad \text{Class B }1.3l_d\ \ \ge\max(20d_b,\ 12\text{ in}) $$
No.10 (32 mm) ์ดˆ๊ณผ ๊ฒน์นจ ๋ถˆ๊ฐ€ (25.5.1.1)
$$\begin{aligned}l_d(f_{fu}) &= 2400\ (\text{์ตœ์†Ÿ๊ฐ’ ๋ฐ ๊ฐ์†Œ ๋ฏธ์ ์šฉ}) \\ l_{lap} &= \max(1.3\times2400,\ 20d_b = 508,\ 300) = \boxed{\mathbf{3{,}121}\ \text{mm}}\ (B๊ธ‰)\end{aligned}$$
$$ l_{lap}\ge\max(12\text{ in},\ 1.3l_d) $$
๋น„์ ‘์ด‰ ์ด์Œ ๊ฐ„๊ฒฉ โ‰ค min(์ด์Œ๊ธธ์ด/5
6 in)
$$\begin{aligned}l_d(f_{fu}) &= 2228\ (\text{์ตœ์†Ÿ๊ฐ’ ๋ฐ ๊ฐ์†Œ ๋ฏธ์ ์šฉ}) \\ l_{lap} &= \max(1.3\times2228,\ 20d_b = 508,\ 300) = \boxed{\mathbf{2{,}896}\ \text{mm}}\ (๋ชจ๋“  ๊ฒฝ์šฐ)\end{aligned}$$
๊ฒน์นจ์ด์Œ (์••์ถ•)
4.5.3 (4.5-1)(4.5-2)
$$ l_s=\left(\frac{1.4f_y}{\lambda\sqrt{f_{ck}}}-52\right)d_b\ \ \text{๋˜๋Š”}\ \ 0.072f_y\,d_b\ (f_y\le400)\ /\ (0.13f_y-24)d_b $$
โ‰ฅ 300
$f_{ck} \lt 21$: ร—4/3
์ธ์žฅ ์ด์Œ๋ณด๋‹ค ๊ธธ ํ•„์š” ์—†์Œ
$$\begin{aligned}l_{s1} &= \left(\frac{1.4\times400}{\sqrt{30}}-52\right)\times25.4 = 1276 \\ l_{s2} &= 0.072\times400\times25.4 = 732 \\ l_s &= \max\big(\min(l_{s1},l_{s2}),\ 300\big) = \boxed{\mathbf{732}\ \text{mm}}\end{aligned}$$
$$ l_{lap,c}=l_{lap}\ (4.7.3.2) $$
์ตœ๋Œ€ ์••์ถ•์‘๋ ฅ $0.25f_{fu}$ ๊ฐ€์ • (4.7.4(2))
$$\begin{aligned}l_{lap,c} &= l_{lap} = \boxed{\mathbf{3{,}121}\ \text{mm}}\end{aligned}$$
ํ•ด๋‹น ์—†์Œ
๊ทœ์ • ์—†์Œ
ํ•ด๋‹น ์—†์Œ
๊ทœ์ • ์—†์Œ
$$ l_{lap,c}=l_{lap}\ (25.5.2) $$
์ธ์žฅ ์ด์Œ ๊ทœ์ • ์ค€์šฉ (๋ณด์ˆ˜์ )
$$\begin{aligned}l_{lap,c} &= l_{lap} = \boxed{\mathbf{3{,}121}\ \text{mm}}\end{aligned}$$
$$ l_{lap,c}\ge\max(12\text{ in},\ 1.3l_d),\qquad l_d\text{ ๋Š” }f_{fr}=0.25f_{fu}\text{ ๋กœ} $$
$$\begin{aligned}l_d(0.25f_{fu}) &= 157 \\ l_{lap,c} &= \max(1.3\times157,\ 20d_b,\ 300) = \boxed{\mathbf{508}\ \text{mm}}\end{aligned}$$
์ •๋ชจ๋ฉ˜ํŠธ ๋ณด๊ฐ•๊ทผ ์ •์ฐฉ
(๋‹จ์ˆœ ๋ฐ›์นจ๋ถ€, ๋ณ€๊ณก์ )
4.4.2 (4.4-1)
$$ l_d\le\frac{\phi M_n}{V_u}+l_a $$
๋ฐ›์นจ๋ถ€ ์••์ถ• ๋ฐ˜๋ ฅ ๊ตฌ์† ์‹œ $\frac{\phi M_n}{V_u}$ ร—1.3
$$\begin{aligned}\frac{\phi M_n}{V_u}+l_a &= \frac{300\times10^6}{180\times10^3}+150 = \boxed{\mathbf{1{,}817}\ \text{mm}} \\ l_d &= 668\ \le\ 1817\ \ \color{#0a8a2a}{\checkmark\ \textbf{OK}}\end{aligned}$$
$$ \text{KDS 14 20 52(4.4.2) ์ค€์šฉ},\qquad l_d\ \text{๋Š” }4.7.1 $$
๋ฐ›์นจ๋ถ€ ์•ˆ์ชฝ ๋ฉด์—์„œ $f_{fu}$ ๋ฐœํœ˜ (2)
$$\begin{aligned}\frac{\phi M_n}{V_u}+l_a &= \frac{300\times10^6}{180\times10^3}+150 = \boxed{\mathbf{1{,}817}\ \text{mm}} \\ l_d &= 2400\ >\ 1817\ \ \color{#d40000}{\times\ \textbf{NG}}\end{aligned}$$
8.1.2(2) (8.1-4)
$$ l_d\le\frac{\phi M_n}{V_u}+l_a $$
$l_a$: ๋ฐ›์นจ๋ถ€ ์ค‘์‹ฌ์„  ์ง€๋‚œ ๋ฌปํž˜๊ธธ์ด / ๋ณ€๊ณก์  $\max(d,\ 12d_b)$
$$\begin{aligned}\frac{\phi M_n}{V_u}+l_a &= \frac{300\times10^6}{180\times10^3}+150 = \boxed{\mathbf{1{,}817}\ \text{mm}} \\ l_d &= 2228\ >\ 1817\ \ \color{#d40000}{\times\ \textbf{NG}}\end{aligned}$$
10.3 (10.3b)
$$ l_d\le\frac{\phi M_n}{V_u}+l_a $$
์••์ถ• ๋ฐ˜๋ ฅ ๊ตฌ์† ์‹œ 30% ์ฆ๊ฐ€ ํ—ˆ์šฉ
$$\begin{aligned}\frac{\phi M_n}{V_u}+l_a &= \frac{300\times10^6}{180\times10^3}+150 = \boxed{\mathbf{1{,}817}\ \text{mm}} \\ l_d &= 2228\ >\ 1817\ \ \color{#d40000}{\times\ \textbf{NG}}\end{aligned}$$
$$ l_d\le\frac{1.3M_n}{V_u}+l_a\ \ (\text{ACI 318 ๋™์ผ}) $$
9์žฅ ๋ณด ์ƒ์„ธ (์•ฑ์€ $\frac{\phi M_n}{V_u}+l_a$ ์ž…๋ ฅ๊ฐ’์œผ๋กœ ๊ฒ€ํ† )
$$\begin{aligned}\frac{\phi M_n}{V_u}+l_a &= \frac{300\times10^6}{180\times10^3}+150 = \boxed{\mathbf{1{,}817}\ \text{mm}} \\ l_d &= 2400\ >\ 1817\ \ \color{#d40000}{\times\ \textbf{NG}}\end{aligned}$$
$$ \text{์ •๋ชจ๋ฉ˜ํŠธ ๋ณด๊ฐ•๊ทผ }\tfrac{1}{3}\ (\text{๋‹จ์ˆœ}),\ \tfrac{1}{4}\ (\text{์—ฐ์†})\ \text{๋ฅผ ๋ฐ›์นจ๋ถ€ ์ค‘์‹ฌ์„  ๋„ˆ๋จธ ์—ฐ์žฅ} $$
LRFD 5.10.8.1.2 ์ค€์šฉ (์•ฑ์€ $\frac{\phi M_n}{V_u}+l_a$ ๋กœ ๊ฒ€ํ† )
$$\begin{aligned}\frac{\phi M_n}{V_u}+l_a &= \frac{300\times10^6}{180\times10^3}+150 = \boxed{\mathbf{1{,}817}\ \text{mm}} \\ l_d &= 2228\ >\ 1817\ \ \color{#d40000}{\times\ \textbf{NG}}\end{aligned}$$
์ด ์•ฑ์˜ ๊ฒ€์ฆ ๊ทผ๊ฑฐ
์›๋ฌธ ๋ˆˆ๋Œ€์กฐ (4.1.1โ€“4.1.6, 4.4.2, 4.5.2, 4.5.3, 2024ํŒ) + ์†๊ณ„์‚ฐ
โœ” 2์ฐจ ๋…๋ฆฝ๊ตฌํ˜„ ๋ฌด์ž‘์œ„ 300์ผ€์ด์Šค ร— 19,200ํ•ญ๋ชฉ ๋Œ€์กฐ ์ผ์น˜ (verify_anchor_independent.py, 0.2%)
์›๋ฌธ ๋ˆˆ๋Œ€์กฐ (4.7.1.1โ€“4.7.1.6, 4.7.2.2, 4.7.3.1โ€“4.7.3.3)
โœ” 2์ฐจ ๋…๋ฆฝ๊ตฌํ˜„ ๋ฌด์ž‘์œ„ 300์ผ€์ด์Šค ร— 19,200ํ•ญ๋ชฉ ๋Œ€์กฐ ์ผ์น˜ (verify_anchor_independent.py, 0.2%)
์›๋ฌธ ๋ˆˆ๋Œ€์กฐ (8.1โ€“8.1.6, ์‹ (8.1-1)โ€“(8.1-5))
โœ” 2์ฐจ ๋…๋ฆฝ๊ตฌํ˜„ ๋ฌด์ž‘์œ„ 300์ผ€์ด์Šค ร— 19,200ํ•ญ๋ชฉ ๋Œ€์กฐ ์ผ์น˜ (verify_anchor_independent.py, 0.2%)
์„ค๊ณ„์˜ˆ์ œ 9M, 10M(SI) ๋Œ€์กฐ ํ†ต๊ณผ(verify_engine.py, ฮฑ ์œ„์น˜) + ์›๋ฌธ 10.1โ€“10.4
โœ” 2์ฐจ ๋…๋ฆฝ๊ตฌํ˜„ ๋ฌด์ž‘์œ„ 300์ผ€์ด์Šค ร— 19,200ํ•ญ๋ชฉ ๋Œ€์กฐ ์ผ์น˜ (verify_anchor_independent.py, 0.2%)
์Šค์บ” ์›๋ฌธ ๋ˆˆ๋Œ€์กฐ (ํ‘œ 25.3.1, 25.4.1โ€“25.4.10, 25.5.1โ€“25.5.7)
2000/37.5/4000 psi = 165/3.1/330
โœ” 2์ฐจ ๋…๋ฆฝ๊ตฌํ˜„ ๋ฌด์ž‘์œ„ 300์ผ€์ด์Šค ร— 19,200ํ•ญ๋ชฉ ๋Œ€์กฐ ์ผ์น˜ (verify_anchor_independent.py, 0.2%)
์Šค์บ” ์›๋ฌธ ๋ˆˆ๋Œ€์กฐ (2.9.7.2โ€“2.9.7.6) โ†’ ๊ฐˆ๊ณ ๋ฆฌ 0.7 ์ œ๊ฑฐ, ์ด์Œ 12 in ์ตœ์†Ÿ๊ฐ’ ๋ฐ˜์˜ (2026-08-30 ์ˆ˜์ • 2๊ฑด)
โœ” 2์ฐจ ๋…๋ฆฝ๊ตฌํ˜„ ๋ฌด์ž‘์œ„ 300์ผ€์ด์Šค ร— 19,200ํ•ญ๋ชฉ ๋Œ€์กฐ ์ผ์น˜ (verify_anchor_independent.py, 0.2%)