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  1. ์„ฑ๊ท ๊ด€๋Œ€ํ•™๊ต ๊ฑด์„คํ™˜๊ฒฝ๊ณตํ•™๋ถ€ ๊ต์ˆ˜ (Professor, School of Civil, Architectural Engineering and Landscape Architecture, Sungkyunkwan University, Suwon 16419, Rep. of Korea)
  2. ์„ฑ๊ท ๊ด€๋Œ€ํ•™๊ต ๊ฑด์„คํ™˜๊ฒฝ์‹œ์Šคํ…œ๊ณตํ•™๊ณผ ๋Œ€ํ•™์›์ƒ (Graduate Student, Department of Civil, Architectural, and Environmental System Engineering, Sungkyunkwan University, Suwon 16419, Rep. of Korea)



ํ”„๋ฆฌ์บ์ŠคํŠธ ์ฝ˜ํฌ๋ฆฌํŠธ, ๋™๋“ฑ์„ฑ, ๋ชจ๋ฉ˜ํŠธ์ €ํ•ญ๊ณจ์กฐ, ํ˜„์žฅํƒ€์„ค ์ฝ˜ํฌ๋ฆฌํŠธ, ๋ณด-๊ธฐ๋‘ฅ ์ ‘ํ•ฉ๋ถ€
precast concrete, emulation, moment resistance frame, cast-in-place concrete, beam-column joints

1. ์„œ ๋ก 

์ง€๋‚œ ์‹ญ์—ฌ ๋…„๊ฐ„ ์„ธ๊ณ„์ ์ธ ๊ฒฝ๊ธฐ์นจ์ฒด์™€ ๊ตญ๋‚ด ๊ฑด์„ค์‹œ์žฅ์˜ ํฌํ™”๋กœ ๊ฑด์„ค๊ฒฝ๊ธฐ๋Š” ๊ทน์‹ฌํ•œ ์นจ์ฒด์— ์ง๋ฉดํ•˜๊ณ  ์žˆ๋‹ค. ํŠนํžˆ ์šฐ๋ฆฌ๋‚˜๋ผ๊ฐ€ ๊ฐœ๋ฐœ๋„์ƒ๊ตญ์—์„œ ์„ ์ง„๊ตญ ๋Œ€์—ด์— ์ง„์ž…ํ•จ์œผ๋กœ์จ ๊ตญ๊ฐ€ ๊ธฐ๊ฐ„์‚ฐ์—…์˜ ์„ฑ์žฅ๋ฅ ์ด ๋‘”ํ™”ํ•˜์˜€๊ณ , ์‹ ๊ทœ ์ฃผํƒ๊ณต๊ธ‰ ์—ญ์‹œ ์ถ•์†Œ๋˜๋ฉด์„œ ๊ฑด์„ค ์‚ฐ์—…์€ ์žฅ๊ธฐ๊ฐ„์˜ ์นจ์ฒด์— ์ง๋ฉดํ•˜๊ณ  ์žˆ๋‹ค. ๋˜ํ•œ 21์„ธ๊ธฐ์— ๋“ค์–ด์„œ๋ฉด์„œ ์šฐ๋ฆฌ๋‚˜๋ผ๋„ ์ดˆ๊ณ ๋ นํ™” ์‚ฌํšŒ์— ์ ‘์–ด๋“ค์—ˆ๋‹ค. ๊ฑด์„ค ๋ถ„์•ผ๋„ ๊ทธ ์˜ํ–ฅ์„ ํ”ผํ•  ์ˆ˜ ์—†์—ˆ๊ธฐ์—, ๊ฑด์„ค ํ˜„์žฅ ์ธ๋ ฅ ๋ถ€์กฑ ํ˜„์ƒ์ด ์ ์  ์‹ฌํ™”๋˜๊ณ  ์žˆ๋‹ค. ์—ฌ๊ธฐ์— ์›์ž์žฌ ๊ฐ€๊ฒฉ์ด ๊ธ‰๊ฒฉํ•˜๊ฒŒ ์ƒ์Šนํ•˜์—ฌ ๊ธฐ์กด ํ˜„์žฅํƒ€์„ค ์ฝ˜ํฌ๋ฆฌํŠธ(cast-in-place concrete, ์ดํ•˜ CPC)๋ฅผ ๋Œ€์ฒดํ•˜๋Š” ์ƒˆ๋กœ์šด ํŒจ๋Ÿฌ๋‹ค์ž„์˜ ์ฝ˜ํฌ๋ฆฌํŠธ ๊ฑด์„ค ๊ธฐ์ˆ ์ด ์š”๊ตฌ๋˜๊ณ  ์žˆ๋‹ค.

์ด๋Ÿฌํ•œ ๋ฌธ์ œ๋ฅผ ํ•ด๊ฒฐํ•  ๋ฐฉ์•ˆ์˜ ํ•˜๋‚˜๋กœ ํ”„๋ฆฌ์บ์ŠคํŠธ ์ฝ˜ํฌ๋ฆฌํŠธ(precast concrete, ์ดํ•˜ PC) ๊ตฌ์กฐ๋ฌผ์˜ ํ™œ์„ฑํ™”๋ฅผ ์ƒ๊ฐํ•  ์ˆ˜ ์žˆ๋‹ค. PC ๊ธฐ์ˆ ์€ ์ด๋ฏธ ์˜ค๋ž˜์ „๋ถ€ํ„ฐ ์•Œ๋ ค์ ธ ์™”๊ณ , PC ๊ตฌ์กฐ์˜ ์žฅ์ ์€ ๋„๋ฆฌ ์•Œ๋ ค์กŒ์ง€๋งŒ, PC ๊ตฌ์กฐ๋ฌผ, ํŠนํžˆ ์ค‘์ธต ์ด์ƒ์˜ PC ๊ตฌ์กฐ๋ฌผ์ด ์šฐ๋ฆฌ๋‚˜๋ผ์—์„œ ๊ฑด์„ค๋œ ์‚ฌ๋ก€๋Š” ๋งŽ์ง€ ์•Š๋‹ค.

์ค‘๊ณ ์ธต์˜ PC ๊ตฌ์กฐ๋ฌผ์„ ๊ฑด์„คํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์ ‘ํ•ฉ๋ถ€, ์กฐ๋ฆฝ, ์–‘์ค‘ ๋“ฑ์˜ ๋‹ค์–‘ํ•œ ๊ธฐ์ˆ  ํ™•๋ณด๊ฐ€ ์š”๊ตฌ๋˜๋ฉฐ, ํŠนํžˆ ๋‚ด์ง„์„ค๊ณ„์™€ ๊ด€๋ จ๋œ ๋ช…ํ™•ํ•œ ๊ธฐ์ค€๊ณผ PC ๋‚ด์ง„ ๊ตฌ์กฐ ์‹œ์Šคํ…œ์˜ ์ œ์‹œ๊ฐ€ ํ•„์š”ํ•˜๋‹ค. ์šฐ๋ฆฌ๋‚˜๋ผ์—์„œ๋Š” ํ”„๋ฆฌ์บ์ŠคํŠธ์ฝ˜ํฌ๋ฆฌํŠธ ์กฐ๋ฆฝ์‹ ๊ฑด์ถ•๊ตฌ์กฐ ์„ค๊ณ„๊ธฐ์ค€(AIK 1992)์„ ๋ฐœ๊ฐ„ํ•˜์—ฌ PC ๊ตฌ์กฐ๋ฌผ์˜ ๊ตฌ์กฐ์‹œ์Šคํ…œ์„ ๋‚ด๋ ฅ๋ฒฝ, ๋ชจ๋ฉ˜ํŠธ์ €ํ•ญ๊ณจ์กฐ, 2์ค‘ ๊ณจ์กฐ์˜ 3์ข…๋ฅ˜๋กœ ๊ตฌ๋ถ„ํ•˜์˜€๋‹ค. ๊ธฐ์ค€์—์„œ๋Š” ์ด๋“ค ๊ตฌ์กฐ๋ฌผ์„ ์ผ์ฒด์‹ ๊ตฌ์กฐ๋กœ ๊ฐ€์ •ํ•˜๊ณ  ํƒ„์„ฑํ•ด์„์„ ์ˆ˜ํ–‰ํ•˜๋˜, ์ ‘ํ•ฉ๋ถ€์˜ ์˜ํ–ฅ์„ ๊ณ ๋ คํ•˜์—ฌ ๊ฐ์†Œ๋œ ํƒ„์„ฑ๊ณ„์ˆ˜๋ฅผ ์‚ฌ์šฉํ•˜๋„๋ก ๊ทœ์ •ํ•˜๊ณ  ์žˆ๋‹ค. ๋˜ํ•œ ๊ตฌ์กฐ๋ฌผ์˜ ๋ณ€์œ„ ์—ฐ์„ฑ๋น„๋ฅผ 2~3์œผ๋กœ ํ•˜๋ฉฐ, ๊ฐ์‡„๋น„๋ฅผ 10 % ์ฆ๊ฐ€์‹œ์ผฐ๋‹ค. ๊ธฐ์ค€์—์„œ๋Š” ๋‚ด๋ ฅ๋ฒฝ๊ตฌ์กฐ, ๋ชจ๋ฉ˜ํŠธ ์—ฐ์„ฑ๊ณจ์กฐ, 2์ค‘ ๊ณจ์กฐ์˜ ๋ฐ˜์‘์ˆ˜์ •๊ณ„์ˆ˜๋ฅผ ๊ฐ๊ฐ โ€œ3โ€, โ€œ4.5โ€, โ€œ4 ๋˜๋Š” 5โ€๋กœ ๊ทœ์ •ํ•˜๊ณ  ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ์ด ๊ธฐ์ค€์ด ํฌํ•จํ•˜๊ณ  ์žˆ๋Š” ๊ตฌ์กฐ์‹œ์Šคํ…œ ๋ฐ ๊ธฐํƒ€ ์ง€์ง„๊ณ„์ˆ˜๋Š” 1992๋…„ ์ด์ „์˜ ๊ฒƒ์œผ๋กœ 2000๋…„๋Œ€ ์ดˆ๋ฐ˜์— ๊ฐœ์ •๋œ ํ˜„์žฌ์˜ ๊ตฌ์กฐ์‹œ์Šคํ…œ๊ณผ ์ฐจ์ด๊ฐ€ ์žˆ์–ด ์ ์šฉํ•˜๋Š”๋ฐ ๋ฌธ์ œ๊ฐ€ ์žˆ๋‹ค.

์ค‘์ง„ ๋˜๋Š” ๊ฐ•์ง„ ์ง€์—ญ์— ํ”„๋ฆฌ์บ์ŠคํŠธ ๊ตฌ์กฐ๋ฌผ์„ ์ ์šฉํ•˜๊ธฐ ์œ„ํ•˜์—ฌ PC ๊ตฌ์กฐ๋ฌผ์˜ ์—ฐ์„ฑ ํ™•๋ณด์— ๊ด€ํ•œ ๋งŽ์€ ์—ฐ๊ตฌ๊ฐ€ ์ˆ˜ํ–‰๋˜์—ˆ๋‹ค. Englekirk([9]1987, [10]1990)๋Š” ๊ฐ•์ง„ ์ง€์—ญ์— ์œ„์น˜ํ•œ PC ์—ฐ์„ฑ ๋ชจ๋ฉ˜ํŠธ์ €ํ•ญ๊ณจ์กฐ ๊ฐœ๋ฐœ์˜ ๊ธฐ๋ณธ ๊ฐœ๋…์„ ์ œ์‹œํ•˜์˜€๋‹ค. ๋˜ํ•œ PC ๊ตฌ์กฐ๋ฌผ์— ์ ์šฉ๋˜๋Š” ํ™œ์ ˆ์  ์ ‘ํ•ฉ๋ถ€, ์—ฐ์„ฑ ์ ‘ํ•ฉ๋ถ€, ๊ฐ•๋„ ์ ‘ํ•ฉ๋ถ€์˜ ์„ค๊ณ„ ๊ณ ๋ ค ์‚ฌํ•ญ์„ ์ œ์‹œํ•˜์˜€๋‹ค. Restrepo ๋“ฑ(1995)์€ ์‹คํ—˜๊ณผ ํ•ด์„์— ๊ทผ๊ฑฐํ•˜์—ฌ ๋‚ด์ง„ ์ €ํ•ญ PC ๊ณจ์กฐ๋ฅผ ๊ตฌ์„ฑํ•˜๋Š” ๋ถ€์žฌ์˜ ์ ‘ํ•ฉ๋ถ€ ์„ค๊ณ„๋ฐฉ๋ฒ•์„ ์ œ์‹œํ•˜์˜€๋‹ค. Palmieri ๋“ฑ(1996)์€ ์ง€์ง„ ๋ฐœ์ƒ ์œ„ํ—˜์ด ๋†’์€ ์ง€์—ญ์— ๊ฑด์„ค๋˜๋Š” PC ๊ณจ์กฐ ๋ถ€์žฌ์˜ ์—ฐ๊ฒฐ ์ƒ์„ธ๋ฒ•์„ ์ œ์•ˆํ–ˆ๋‹ค. ์ด ๋ฐ–์—๋„ Ochs and Ehsani(1993), Soubra ๋“ฑ(1993)๋„ PC ๊ตฌ์กฐ๋ฌผ์˜ ๋‚ด์ง„์„ค๊ณ„ ๋ฐฉ๋ฒ•์„ ์ œ์‹œํ•˜์˜€๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๋Œ€๋ถ€๋ถ„์˜ ์—ฐ๊ตฌ๋Š” PC ์ ‘ํ•ฉ ์ƒ์„ธ๋‚˜ ์—ฐ์„ฑ ํ‰๊ฐ€์— ๋Œ€ํ•œ ์—ฐ๊ตฌ์ด๋ฉฐ PC ๋ถ€์žฌ์˜ ๋™๋“ฑ์„ฑ ํ‰๊ฐ€์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋Š” ๊ฑฐ์˜ ์—†๋‹ค.

๋ฏธ๊ตญ์˜ PC ๋‚ด์ง„์„ค๊ณ„์— ๊ด€ํ•œ ๊ทœ์ •์€ FEMA(1994)์—์„œ ๊ทœ์ •ํ•˜๋Š” NEHRP(national earthquake hazards reduction program)์—์„œ ์ฒ˜์Œ์œผ๋กœ ๋ฐ˜์˜๋˜์—ˆ๋‹ค. NEHRP์—์„œ๋Š” PC ๊ตฌ์กฐ๋ฌผ์„ ์Šต์‹ ์ ‘ํ•ฉ๋ถ€๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ CPC์™€ ๋™์ผํ•œ ์„ฑ๋Šฅ์„ ๊ฐ–๋Š” ๊ตฌ์กฐ๋ฌผ๊ณผ ๊ฑด์‹ ์ ‘ํ•ฉ๋ถ€๋กœ ์—ฐ๊ฒฐ๋œ ๊ตฌ์กฐ๋ฌผ๋กœ ๊ตฌ๋ถ„ํ•˜์˜€๋‹ค. ์ด ๊ทœ์ •์€ UBC(ICBO 1997)๋…„ ๊ทœ์ •์— ๋ฐ˜์˜๋˜์—ˆ์ง€๋งŒ UBC(1997) ๊ทœ์ •์—๋Š” PC ๊ณจ์กฐ์— ๊ด€ํ•œ ๊ทœ์ •๋งŒ์ด ์ œ์‹œ๋˜์—ˆ๊ณ  ๊ตฌ์กฐ๋ฒฝ์ฒด์— ๋Œ€ํ•œ ๊ทœ์ •์€ ์ œ์‹œํ•˜์ง€ ์•Š์•˜๋‹ค. UBC(1997)์—์„œ๋Š” PC ๊ณจ์กฐ๋ฅผ ์Šต์‹ ์ ‘ํ•ฉ๋ถ€๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ์ผ์ฒด์‹ ๊ตฌ์กฐ๋ฌผ๊ณผ ๋™์ผํ•œ ์„ฑ๋Šฅ์„ ๋‚˜ํƒ€๋‚ด๋Š” ๊ตฌ์กฐ๋ฌผ๊ณผ ๊ฐ•๋„์ ‘ํ•ฉ๋ถ€๋กœ ์—ฐ๊ฒฐ๋œ ๊ตฌ์กฐ๋ฌผ๋กœ ๊ตฌ๋ถ„ํ•˜์˜€๋‹ค. NEHRP(FEMA 2000)์—์„œ๋Š” ์ง€์ง„์ €ํ•ญ๊ณจ์กฐ๋ฅผ ๋ณดํ†ต, ์ค‘๊ฐ„, ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ๋กœ ๊ตฌ๋ถ„ํ•˜๊ณ  ๊ตฌ์กฐ๋ฒฝ์ฒด๋ฅผ ๋ณดํ†ต, ํŠน์ˆ˜๊ตฌ์กฐ๋ฒฝ์ฒด๋กœ ๊ตฌ๋ถ„ํ•˜์˜€๋‹ค. ๋˜ํ•œ NEHRP(2000)์—์„œ๋Š” PC ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ ์ ‘ํ•ฉ๋ถ€๋ฅผ ๊ฐ•๋„์ ‘ํ•ฉ๋ถ€์™€ ์—ฐ์„ฑ์ ‘ํ•ฉ๋ถ€๋กœ ๊ตฌ๋ถ„ํ•œ ํ›„์— ๊ฐ๊ฐ์˜ ์ ‘ํ•ฉ๋ถ€์˜ ์„ค๊ณ„์กฐ๊ฑด์„ ๊ทœ์ •ํ•˜์˜€์œผ๋ฉฐ, PC ํŠน์ˆ˜๊ตฌ์กฐ๋ฒฝ์ฒด ์—ฐ์„ฑ์ ‘ํ•ฉ๋ถ€์˜ ์„ค๊ณ„์กฐ๊ฑด์„ ๊ทœ์ •ํ•˜์˜€๋‹ค. ACI 318-02(2002) ๊ธฐ์ค€์—์„œ๋Š” NEHRP(2000)์— ๊ทผ๊ฑฐํ•˜์—ฌ ์ง€์ง„์ €ํ•ญ๊ณจ์กฐ๋ฅผ ๋ณดํ†ต, ์ค‘๊ฐ„, ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ๋กœ ๊ตฌ๋ถ„ํ•˜๊ณ  ๊ตฌ์กฐ๋ฒฝ์ฒด๋ฅผ ๋ณดํ†ต, ํŠน์ˆ˜๊ตฌ์กฐ๋ฒฝ์ฒด๋กœ ๊ตฌ๋ถ„ํ•˜์˜€๋‹ค. ๋˜ํ•œ PC ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ์˜ ๊ฐ•๋„์ ‘ํ•ฉ๋ถ€์™€ ์—ฐ์„ฑ์ ‘ํ•ฉ๋ถ€, ํŠน์ˆ˜๊ตฌ์กฐ๋ฒฝ์ฒด ์—ฐ์„ฑ์ ‘ํ•ฉ๋ถ€์˜ ์„ค๊ณ„์กฐ๊ฑด์„ ๊ทœ์ •ํ•˜์˜€๋‹ค. ACI 318-11(2011)๊ธฐ์ค€์—์„œ๋Š” PC ์ค‘๊ฐ„๊ตฌ์กฐ๋ฒฝ์ฒด์— ๋ฒฝ๊ธฐ๋‘ฅ(wall pier)์— ๋Œ€ํ•œ ๊ทœ์ •์ด ์ถ”๊ฐ€๋˜์—ˆ์œผ๋ฉฐ ์ด ๊ทœ์ •์ด ์ง€๊ธˆ๊นŒ์ง€ ์ง€์†๋˜๊ณ  ์žˆ๋‹ค. ์ด๋Ÿฌํ•œ PC์„ค๊ณ„ ๊ธฐ์ค€์˜ ๋ฐœ์ „ ๊ณผ์ •์„ ๊ณ ๋ คํ•  ๋•Œ PC ๊ตฌ์กฐ๋ฌผ ๋‚ด์ง„์„ค๊ณ„๋ฅผ ์œ„ํ•ด์„œ๋Š” ๊ธฐ๋ณธ์ ์œผ๋กœ ๋‹ค์Œ ํ•ญ๋ชฉ์— ๋Œ€ํ•œ ๊ทœ์ • ๋˜๋Š” ๊ธฐ์ˆ ์ด ์š”๊ตฌ๋œ๋‹ค.

โ‘  ๋™๋“ฑ์„ฑ(emulation) ํ‰๊ฐ€

โ‘ก PC ๊ตฌ์กฐ๋ฌผ์˜ ๊ตฌ์กฐ์‹œ์Šคํ…œ ๊ตฌ๋ถ„

โ‘ข PC ๊ตฌ์กฐ๋ฌผ์˜ ์ง€์ง„๊ณ„์ˆ˜

โ‘ฃ PC ๋‚ด์ง„ ๊ตฌ์กฐ๋ฌผ์˜ ์ ‘ํ•ฉ ์ƒ์„ธ ๋ฐ ์ ‘ํ•ฉ ๋ฐฉ๋ฒ•

์œ„์˜ ๋™๋“ฑ์„ฑ(emulation)์ด๋ž€ PC ๊ตฌ์กฐ๋ฌผ ๋‚ด์ง„์„ค๊ณ„์˜ ๊ธฐ๋ณธ ์„ค๊ณ„์›์น™์œผ๋กœ โ€œPC ๊ตฌ์กฐ๋ฌผ์ด ์ผ์ฒด์‹ ๊ตฌ์กฐ๋ฌผ์—์„œ ์š”๊ตฌ๋˜๋Š” ์•ˆ์ „์„ฑ ๋ฐ ์‚ฌ์šฉ์„ฑ์— ๊ด€ํ•œ ์กฐ๊ฑด์„ ๋ชจ๋‘ ๊ฐ–์ถ”๊ณ  ์žˆ๋‹ค๋Š” ์กฐ๊ฑดโ€์„ ์˜๋ฏธํ•œ๋‹ค. ๋‚ด์ง„์„ค๊ณ„๋˜๋Š” PC ๊ตฌ์กฐ๋ฌผ์˜ ์ง€์ง„๊ณ„์ˆ˜๋Š” ๋™๋“ฑ์„ฑ๊ณผ ๋ฐ€์ ‘ํ•œ ๊ด€๋ จ์ด ์žˆ๋‹ค. ๋งŒ์ผ PC ๊ตฌ์กฐ๋ฌผ์ด CPC ๊ตฌ์กฐ๋ฌผ๊ณผ ๋™์ผํ•œ ๊ตฌ์กฐ ์„ฑ๋Šฅ์„ ๊ฐ–๊ณ  ์žˆ๋‹ค๋ฉด RC ๊ตฌ์กฐ๋ฌผ์˜ ๊ตฌ์กฐ์‹œ์Šคํ…œ๊ณผ ์ง€์ง„๊ณ„์ˆ˜๋ฅผ ๊ทธ๋Œ€๋กœ ์‚ฌ์šฉํ•ด๋„ ๋ฌด๋ฐฉํ•˜๊ฒŒ ๋˜๋ฉฐ, ๊ทธ๋ ‡์ง€ ๋ชปํ•  ๊ฒฝ์šฐ์—๋Š” ์ง€์ง„๊ณ„์ˆ˜๋ฅผ ๋ณ€๊ฒฝํ•ด์•ผ ํ•œ๋‹ค.

PC ๊ตฌ์กฐ๋ฌผ์˜ ๋™๋“ฑ์„ฑ์— ๊ด€ํ•˜์—ฌ ACI 374.1-05(2005), ACI PRC-550.1-09(2017), ACI ITG 5.1-07(2008)์—์„œ๋Š” ์‹คํ—˜ ๋ฐฉ๋ฒ• ๋ฐ ๊ตฌ์กฐ ์„ฑ๋Šฅ์ ์„ ์ œ์‹œํ•˜๊ณ  ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ์—ฌ๊ธฐ์„œ ์ œ์‹œํ•˜๋Š” ๊ฒƒ์€ โ€œํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐโ€์™€ โ€œํŠน์ˆ˜๊ตฌ์กฐ๋ฒฝ์ฒดโ€์— ๊ด€ํ•œ ๊ฒƒ์ด๋ฉฐ ํ˜„์žฌ ์šฐ๋ฆฌ๋‚˜๋ผ์—์„œ ๋„๋ฆฌ ์ ์šฉํ•˜๊ณ  ์žˆ๋Š” โ€œ์ค‘๊ฐ„๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐโ€์— ๋Œ€ํ•œ ๊ทœ์ •์ด ํฌํ•จ๋˜์–ด ์žˆ์ง€ ์•Š๋‹ค. ์ผ๋ณธ๊ฑด์ถ•ํ•™ํšŒ์˜ ํ˜„์žฅํƒ€์„ค ๋™๋“ฑํ˜• PC ๊ตฌ์กฐ์„ค๊ณ„์ง€์นจ ๋ฐ ํ•ด์„ค(AIJ 2002)์—์„œ๋„ PC ๊ตฌ์กฐ๋ฌผ์ด CPC ๊ตฌ์กฐ๋ฌผ์˜ ์„ฑ๋Šฅ์„ ์ธ์ •๋ฐ›๊ธฐ ์œ„ํ•œ ๊ธฐ๋ณธ ์กฐ๊ฑด์„ ์ œ์‹œํ•˜๊ณ  ์žˆ์ง€๋งŒ, ์—ฌ๊ธฐ์„œ๋Š” ๊ฑด์‹ PC๋Š” ์ œ์™ธํ•˜๊ณ  ์Šต์‹ PC๋งŒ์„ ๋Œ€์ƒ์œผ๋กœ ํ•œ๋‹ค.

์ด ๋…ผ๋ฌธ์—์„œ๋Š” 150๊ฐœ ์‹คํ—˜์ฒด์˜ ๊ตฌ์กฐ์„ฑ๋Šฅ์„ ๋ถ„์„ํ•˜์—ฌ PC ๋ชจ๋ฉ˜ํŠธ์ €ํ•ญ๊ณจ์กฐ์˜ ๋™๋“ฑ์„ฑ์— ๋Œ€ํ•œ ๊ธฐ๋ณธ ์„ฑ๋Šฅ์„ ์ œ์‹œํ•˜๊ณ ์ž ํ•œ๋‹ค.

2. PC ๊ตฌ์กฐ๋ฌผ ๋™๋“ฑ์„ฑ ํ‰๊ฐ€ ์ง€์นจ ๋น„๊ต

PC ๊ตฌ์กฐ๋ฌผ ๋‚ด์ง„์„ค๊ณ„์˜ ๊ธฐ๋ณธ ์„ค๊ณ„์›์น™์€ PC ๊ตฌ์กฐ๋ฌผ์ด ์ผ์ฒด์‹ ๊ตฌ์กฐ๋ฌผ์—์„œ ์š”๊ตฌ๋˜๋Š” ์•ˆ์ „์„ฑ ๋ฐ ์‚ฌ์šฉ์„ฑ์„ ํ™•๋ณดํ•˜๊ณ  ์žˆ์–ด์•ผ ํ•œ๋‹ค๋Š” ๊ทœ์ •์ด๋‹ค. ์ฝ˜ํฌ๋ฆฌํŠธ๊ตฌ์กฐ ํ•™ํšŒ๊ธฐ์ค€(KCI 2017)์ด๋‚˜ ACI 318-19(ACI 2019)๊ธฐ์ค€์—์„œ๋Š” โ€œํ”„๋ฆฌ์บ์ŠคํŠธ ์ฝ˜ํฌ๋ฆฌํŠธ ๊ตฌ์กฐ ์‹œ์Šคํ…œ์ด ์‹คํ—˜์ด๋‚˜ ํ•ด์„์— ์˜ํ•ด ๊ธฐ์ค€์—์„œ ์š”๊ตฌํ•˜๋Š” ์ถฉ๋ถ„ํ•œ ๊ฐ•๋„์™€ ์ธ์„ฑ์„ ๋ณด์œ ํ•˜๋Š” ๊ฒƒ์œผ๋กœ ์ž…์ฆ๋œ๋‹ค๋ฉด ๋‚ด์ง„ ์‹œ์Šคํ…œ์œผ๋กœ ์‚ฌ์šฉํ•  ์ˆ˜ ์žˆ๋‹ค.โ€๋Š” ๊ฒƒ์ด๋‹ค. ํ˜„์žฌ ACI(2019)์—์„œ๋Š” PC๋ฅผ RC์™€ ๊ตฌ๋ณ„ํ•˜์—ฌ ์„ค๊ณ„ํ•˜์ง€ ์•Š์œผ๋ฉฐ, PC์˜ ๊ณ ์œ ํŠน์„ฑ์— ๋Œ€ํ•œ ์„ค๊ณ„์ƒ์˜ ์œ ์˜์ ๋งŒ์„ ์ œ์‹œํ•  ๋ฟ์ด๋‹ค. ๋‹ค๋งŒ, ์šฐ๋ฆฌ๋‚˜๋ผ ๊ธฐ์ค€์—์„œ๋Š” ์–ด๋–ป๊ฒŒ PC ๊ตฌ์กฐ์‹œ์Šคํ…œ์ด ์š”๊ตฌํ•˜๋Š” ์ถฉ๋ถ„ํ•œ ๊ฐ•๋„์™€ ์ธ์„ฑ์„ ๋ณด์œ ํ•˜๋Š” ์žˆ๋Š” ์ง€๋ฅผ ์ธก์ •ํ•  ์ˆ˜ ์žˆ๋Š” ๋ฐฉ๋ฒ•์„ ์ œ์‹œํ•˜์ง€ ์•Š๊ณ  ์žˆ๋‹ค. ๋ฐ˜๋ฉด ACI 318(2019) ๊ธฐ์ค€์—์„œ๋Š” ACI 374.1-05(2005)๋‚˜ ACI ITG 5.1-07(2008)์„ ๋งŒ์กฑํ•˜๋ฉด ์ผ์ฒด์‹ ๊ตฌ์กฐ๋ฌผ๋กœ ์ธ์ •ํ•˜๊ณ  ์žˆ๋‹ค. ์ผ๋ณธ๊ฑด์ถ•ํ•™ํšŒ์˜ ๊ฒฝ์šฐ์—๋„ CPC ๊ตฌ์กฐ๋ฌผ๋กœ ์ธ์ •๋ฐ›๊ธฐ ์œ„ํ•œ PC ๊ตฌ์กฐ๋ฌผ์˜ ๊ตฌ์กฐ๊ฑฐ๋™ ํŠน์„ฑ์„ ์ •ํ•˜๊ณ  ์žˆ๋‹ค.

์ด ์—ฐ๊ตฌ์—์„œ๋Š” PC ๊ตฌ์กฐ๋ฌผ์˜ ๋™๋“ฑ์„ฑ์„ ํ‰๊ฐ€ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ์™€ ๊ด€๋ จ๋œ ACI 374.1-05(2005) ์ง€์นจ๊ณผ ์Šต์‹ PC์™€ ๊ด€๋ จ๋œ โ€œํ˜„์žฅํƒ€์„ค ๋™๋“ฑํ˜• PC ๊ตฌ์กฐ์„ค๊ณ„์ง€์นจ ๋ฐ ํ•ด์„คโ€(AIJ 2002)์„ ๋‹ค์Œ๊ณผ ๊ฐ™์ด ๋น„๊ต ๋ถ„์„ํ•˜์˜€๋‹ค.

2.1 ACI 374.1-05 ์ง€์นจ

ACI 374.1-05(2005) ์ง€์นจ โ€œ๊ตฌ์กฐ ์‹คํ—˜์— ์˜ํ•œ ๋ชจ๋ฉ˜ํŠธ์ €ํ•ญ๊ณจ์กฐ์˜ ํ—ˆ์šฉ ๊ธฐ์ค€โ€์—์„œ๋Š” ์ง€์ง„ ์œ„ํ—˜์ด ๋†’์€ ์ง€์—ญ์˜ ๊ตฌ์กฐ๋ฌผ ์„ค๊ณ„์—์„œ ์•ฝ๋ณด-๊ฐ•๊ธฐ๋‘ฅ ๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ์˜ ์ตœ์†Œ ์š”๊ตฌ ์กฐ๊ฑด์„ ๋‚˜ํƒ€๋‚ด๋Š” ์‹คํ—˜ ์„ฑ๋Šฅ์„ ์ œ์‹œํ•˜๊ณ  ์žˆ๋‹ค. ์—ฌ๊ธฐ์„œ๋Š” ์‹คํ—˜์ฒด์˜ ํฌ๊ธฐ, ํ˜•์ƒ, ๋ฐฉ๋ฒ•, ์‹คํ—˜ ๊ฒฐ๊ณผ ๋ณด๊ณ ์„œ, ์‹คํ—˜์ฒด์˜ ์„ฑ๋Šฅ ๋“ฑ์— ๋Œ€ํ•œ ๊ตฌ์ฒด์ ์ธ ํ‰๊ฐ€ ํ•ญ๋ชฉ์„ ์ œ์‹œํ•˜๊ณ  ์žˆ๋‹ค. ACI 374.1-05 ์ง€์นจ์—์„œ๋Š” ๋‹ค์Œ ๋‘ ๊ฐ€์ง€ ์กฐ๊ฑด์„ ๋ชจ๋‘ ์ถฉ์กฑํ•  ๊ฒฝ์šฐ์— PC ๋ชจ๋ฉ˜ํŠธ์ €ํ•ญ๊ณจ์กฐ๋ฅผ CPC ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ๋กœ ๊ฐ„์ฃผํ•œ๋‹ค.

โ‘  ACI 374.1-05 ์ง€์นจ ์š”๊ตฌ ์กฐ๊ฑด์— ์˜ํ•ด ์‹คํ—˜ํ•œ ๊ณจ์กฐ ๋ถ€์žฌ์˜ ๊ฐ•๋„, ๋ณ€์œ„-ํšŒ์ „ ์„ฑ๋Šฅ, ์ƒ๋Œ€ ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„, ๊ฐ•์„ฑ์ด ํ—ˆ์šฉ ์กฐ๊ฑด์„ ๋งŒ์กฑํ•ด์•ผ ํ•œ๋‹ค.

โ€ข ์‹คํ—˜์ฒด์˜ ๋ณ€์œ„๋น„๊ฐ€ IBC ๊ธฐ์ค€(ICC 2012)์˜ ํ—ˆ์šฉ ์ธต๊ฐ„ ๋ณ€์œ„๋น„์— ๋„๋‹ฌํ•˜๊ธฐ ์ „์— ์‹คํ—˜์ฒด์˜ ํšก๊ฐ•๋„(ํ•˜์ค‘ ๋˜๋Š” ๋ชจ๋ฉ˜ํŠธ)๊ฐ€ ๊ณต์นญํšก๊ฐ•๋„(ํ•˜์ค‘ ๋˜๋Š” ๋ชจ๋ฉ˜ํŠธ), $E_{n}$ ์ด์ƒ์ด ๋˜์–ด์•ผ ํ•œ๋‹ค.

โ€ข ์ตœ๋Œ€ ํšก๊ฐ•๋„, $E_{\max}$๋Š” ์ดˆ๊ณผ๊ณ„์ˆ˜($\lambda$)๋ฅผ ๊ณฑํ•œ ํšก๊ฐ•๋„( $\lambda E_{n}$)๋ฅผ ์ดˆ๊ณผํ•ด์„œ๋Š” ์•ˆ ๋œ๋‹ค.

โ€ข ๋ณ€์œ„๋น„(drift ratio) 0.035์—์„œ 3๋ฒˆ์งธ ์ด๋ ฅ ์ปค๋ธŒ๋Š” ๋‹ค์Œ์„ ๋งŒ์กฑํ•ด์•ผ ํ•œ๋‹ค.

- ์ตœ๋Œ€ ํ•˜์ค‘์ด ๊ฐ™์€ ํ•˜์ค‘ ๋ฐฉํ–ฅ์˜ $E_{\max}$์˜ 0.75๋ฐฐ ์ด์ƒ

- ์ƒ๋Œ€ ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„๊ฐ€ 1/8 ์ด์ƒ์ผ ๊ฒƒ

- 0.0035์˜ ๋ณ€์œ„๋น„์—์„œ ๊ฐ•์„ฑ์ด ์ดˆ๊ธฐ ๊ฐ•์„ฑ์˜ 0.05๋ฐฐ ์ด์ƒ์ผ ๊ฒƒ

โ‘ก ์œ„์˜ โ‘ ์˜ ์„ฑ๋Šฅ์„ ๊ฐ–์ถ˜ ๋ถ€์žฌ๋กœ ์ด๋ฃจ์–ด์ง„ ๊ณจ์กฐ๋Š” ๋ณ€์œ„๋น„ 0.035 ์ด์ƒ๊นŒ์ง€ ๊ตฌ์กฐ๋ฌผ์˜ ๊ฐ•๋„ ๋ฐ ์‚ฌ์šฉ์„ฑ์—์„œ ํฐ ํ•˜์ž๊ฐ€ ๋ฐœ์ƒํ•˜์ง€ ์•Š๊ณ , ์ง€์ง„์— ์˜ํ•ด ๋ฐœ์ƒํ•˜๋Š” ์ตœ๋Œ€ ํšก๋ณ€์œ„์—์„œ ์ค‘๋ ฅ ํ•˜์ค‘์„ ์ง€์ง€ํ•ด์•ผ ํ•œ๋‹ค.

2.2 ์ผ๋ณธ๊ฑด์ถ•ํ•™ํšŒ-ํ˜„์žฅํƒ€์„ค ๋™๋“ฑํ˜• PC ๊ตฌ์กฐ์„ค๊ณ„์ง€์นจ

์ผ๋ณธ๊ฑด์ถ•ํ•™ํšŒ์˜ โ€œํ˜„์žฅํƒ€์„ค ๋™๋“ฑํ˜• PC ๊ตฌ์กฐ์„ค๊ณ„์ง€์นจ ๋ฐ ํ•ด์„คโ€(AIJ 2002)์—์„œ๋Š” CPC ๊ตฌ์กฐ๋ฌผ๊ณผ ๋™๋“ฑํ•œ ์„ฑ๋Šฅ์„ PC ๊ตฌ์กฐ๋ฌผ์ด ์ธ์ •๋ฐ›๋„๋ก ํ•˜๊ธฐ ์œ„ํ•œ ๊ธฐ๋ณธ ์กฐ๊ฑด์„ ๋ฏธ๊ตญ๊ณผ ๋‹ค๋ฅด๊ฒŒ ํ•˜๊ณ  ์žˆ๋‹ค. ์—ฌ๊ธฐ์„œ๋Š” ์ ‘ํ•ฉ๋ถ€๊ฐ€ ํ˜„์žฅํƒ€์„ค ์ฝ˜ํฌ๋ฆฌํŠธ์™€ ์ผ์ฒดํ™”๋˜๊ณ , ์ฒ ๊ทผ์˜ ์—ฐ์†์„ฑ์ด ํ™•๋ณด๋˜๋Š” ์ ‘ํ•ฉ ๋ฐฉ๋ฒ•, ์ฆ‰ ์Šต์‹์ ‘ํ•ฉ(wet- connection) ๋ฐฉ์‹์„ ๊ธฐ๋ณธ์œผ๋กœ ํ•œ๋‹ค. ๋˜ํ•œ PC ๊ตฌ์กฐ์‹œ์Šคํ…œ์ด ๊ทนํ•œ์ƒํƒœ์— ๋„๋‹ฌํ–ˆ์„ ๋•Œ ์†Œ์„ฑํžŒ์ง€์˜์—ญ ์•ˆ์— ์ ‘ํ•ฉ๋ถ€๊ฐ€ ์žˆ๋Š” PC ๋ถ€์žฌ๋Š” ๋‹ค์Œ์˜ ์„ฑ๋Šฅ์„ ํ™•๋ณดํ•ด์•ผ ํ•œ๋‹ค.

โ‘  PC ๋ถ€์žฌ์˜ ํœจํ•ญ๋ณต๊ฐ•๋„๋Š” CPC ๋ถ€์žฌ์˜ ํœจํ•ญ๋ณต๊ฐ•๋„ ์ด์ƒ์ด ๋˜์–ด์•ผ ํ•œ๋‹ค.

โ‘ก PC ๋ถ€์žฌ์˜ ๊ฐ•๋„๋Š” CPC ๋ถ€์žฌ์˜ ๊ฐ•๋„ ์ด์ƒ์ด ๋˜์–ด์•ผ ํ•œ๋‹ค.

โ‘ข ์„ค๊ณ„์—์„œ ํ—ˆ์šฉํ•˜๋Š” ๋ณ€ํ˜• ๋‚ด์—์„œ ๋ฐ˜๋ณตํ•˜์ค‘์„ ๋ฐ›๋Š” PC ๋ถ€์žฌ์˜ ๊ฐ•๋„๋Š” CPC ๋ถ€์žฌ์˜ ๊ฐ•๋„ ์ด์ƒ์ด ๋˜์–ด์•ผ ํ•œ๋‹ค. ๋ณด-๊ธฐ๋‘ฅ ์ ‘ํ•ฉ๋ถ€๊ฐ€ ์žˆ๋Š” PC ๋ถ€์žฌ๋Š” ๋ณ€์œ„๋น„๊ฐ€ 0.02์ผ ๋•Œ ๋‹จ์กฐํ•˜์ค‘ ๊ฐ€๋ ฅ ์‹œ์˜ ํ•˜์ค‘์ด๋ ฅ ํฌ๋ฝ์„ ๋ณด๋‹ค ๋‚ด๋ ฅ์ด ๋–จ์–ด์ง€์ง€ ์•Š์•„์•ผ ํ•˜๋ฉฐ, ๋™์ผํ•œ ๋ณ€ํ˜•์—์„œ ๋ฐ˜๋ณตํ•˜์ค‘์„ ๋ฐ›์„ ๋•Œ ๋‚ด๋ ฅ๊ฐ์†Œ์œจ์ด 80 % ์ด๋‚ด์— ๋จธ๋ฌผ๋Ÿฌ์•ผ ํ•œ๋‹ค. ๋ชจ๋ฅดํƒ€๋ฅด ์ถฉ์ง„ ์Šฌ๋ฆฌ๋ธŒ ๋“ฑ๊ณผ ๊ฐ™์€ PC ์ ‘ํ•ฉ๋ถ€์˜ ์ ‘ํ•ฉ์ฒ ๋ฌผ์— ์˜ํ•ด ๋ณ€ํ˜•๋ฅ  ๊ฒฝํ™”ํ˜„์ƒ์ด ๋ฐœ์ƒํ•˜์ง€ ์•Š์•„์•ผ ํ•œ๋‹ค. ๋ณ€ํ˜•๋ฅ  ๊ฒฝํ™”ํ˜„์ƒ์ด ๋ฐœ์ƒํ•  ๊ฒฝ์šฐ ํŒŒ๊ดด๋ชจ๋“œ๊ฐ€ ๋ณ€ํ•˜๊ฑฐ๋‚˜ ํŒŒ๊ดด ์œ„์น˜๊ฐ€ ๋ฐ”๋€” ์ˆ˜ ์žˆ๋‹ค.

โ‘ฃ PC ๋ถ€์žฌ์˜ ํœจํ•ญ๋ณต ์‹œ์˜ ๋ณ€ํ˜•์€ CPC ๋ถ€์žฌ์˜ ํœจํ•ญ๋ณต์‹œ์˜ ๋ณ€ํ˜•๊ณผ 20 % ์ด์ƒ์˜ ํฐ ์ฐจ์ด๊ฐ€ ์žˆ์–ด์„œ๋Š” ์•ˆ ๋œ๋‹ค.

โ‘ค ์„ค๊ณ„์—์„œ ํ—ˆ์šฉํ•˜๋Š” ๋ณ€ํ˜• ๋‚ด์—์„œ ๋ฐ˜๋ณตํ•˜์ค‘์„ ๋ฐ›๋Š” PC ๋ถ€์žฌ์˜ ๊ฐ•๋„๋Š” CPC ๋ถ€์žฌ์˜ ๊ฐ•๋„ ์ด์ƒ์ด ๋˜์–ด์•ผ ํ•œ๋‹ค. ๋ณด-๊ธฐ๋‘ฅ ์ ‘ํ•ฉ๋ถ€๊ฐ€ ์žˆ๋Š” PC ๋ถ€์žฌ๋Š” ๋ณ€์œ„๋น„๊ฐ€ 0.02์ผ ๋•Œ ๋™์ผํ•œ ๋ณ€ํ˜•์—์„œ 2๋ฒˆ์งธ ๋ฐ˜๋ณตํ•˜์ค‘์„ ๋ฐ›์„ ๋•Œ์˜ ์—๋„ˆ์ง€ ์†Œ์‚ฐ์€ ๋™์ผํ•œ ์กฐ๊ฑด์˜ CPC ๋ถ€์žฌ์˜ 80 % ์ด๋‚ด์— ๋จธ๋ฌผ๋Ÿฌ์•ผ ํ•œ๋‹ค.

์ด์™€ ๊ฐ™์ด ์ผ๋ณธ๊ฑด์ถ•ํ•™ํšŒ์™€ ACI 374.1-05 ์ง€์นจ์˜ ๋™๋“ฑ์„ฑ ์กฐ๊ฑด์€ ๊ฐ•๋„, ๊ฐ•์„ฑ, ์—๋„ˆ์ง€ ์†Œ์‚ฐ์„ ์ œํ•œํ•˜๋Š” ๊ฒƒ์€ ๋™์ผํ•˜์ง€๋งŒ, ์—ฐ์„ฑ์˜ ํ•œ๊ณ„์™€ ์ ‘ํ•ฉ ๋ฐฉ์‹์— ๋Œ€ํ•ด์„œ๋Š” ์ฐจ์ด๊ฐ€ ์žˆ๋‹ค.

3. ๋ชจ๋ฉ˜ํŠธ ์ €ํ•ญ PC ๊ตฌ์กฐ๋ฌผ์˜ ์‹คํ—˜ ๊ฒฐ๊ณผ ๋ถ„์„

2์žฅ์—์„œ ์ œ์‹œ๋œ ๋™๋“ฑ์„ฑ ํ‰๊ฐ€๋Š” ๊ฐ๊ฐ ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ์™€ ์Šต์‹ PC๋ฅผ ๊ธฐ๋ณธ์œผ๋กœ ํ•˜๊ธฐ ๋•Œ๋ฌธ์— ์šฐ๋ฆฌ ์‹ค์ •์— ๋งž๋Š” PC ๊ตฌ์กฐ๋ฌผ์˜ ๋™๋“ฑ์„ฑ์„ ํ‰๊ฐ€ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ 150๊ฐœ์˜ ์‹คํ—˜์ฒด๋ฅผ ์ทจํ•ฉํ•˜์˜€๋‹ค. ์ทจํ•ฉ๋œ ์‹คํ—˜์ฒด ์ค‘์—์„œ ์—ฐ๊ฒฐ ์ฒ ๋ฌผ์˜ ์†์ƒ๊ณผ ๊ฐ™์€ ๋น„๊ตฌ์กฐ์ฒด ํŒŒ๊ดด ์‹คํ—˜์ฒด๋ฅผ ์ œ์™ธํ•˜์˜€๋‹ค. ACI 374.1-05 ์ง€์นจ๊ณผ โ€œํ˜„์žฅํƒ€์„ค ๋™๋“ฑํ˜• PC ๊ตฌ์กฐ์„ค๊ณ„์ง€์นจโ€(AIJ 2002)์—์„œ ๋ชจ๋ฉ˜ํŠธ์ €ํ•ญ๊ณจ์กฐ์˜ ๋™๋“ฑ์„ฑ์„ ๋ณด-๊ธฐ๋‘ฅ ์ ‘ํ•ฉ๋ถ€์˜ ๊ฑฐ๋™์„ ๊ธฐ์ค€์œผ๋กœ ํ‰๊ฐ€ํ•˜๊ณ  ์žˆ์œผ๋ฏ€๋กœ ์ด ๋…ผ๋ฌธ์—์„œ๋„ PC ๋ณด-๊ธฐ๋‘ฅ ์ ‘ํ•ฉ๋ถ€ ์‹คํ—˜์„ ๋Œ€์ƒ์œผ๋กœ ํ•˜์˜€๋‹ค.

3.1 ์‹คํ—˜์ฒด์˜ ํŠน์„ฑ

150๊ฐœ ๋ณด-๊ธฐ๋‘ฅ ์ ‘ํ•ฉ๋ถ€๋Š” 123๊ฐœ์˜ ๋‚ด๋ถ€ ์ ‘ํ•ฉ๋ถ€์™€ 27๊ฐœ์˜ ์™ธ๋ถ€ ์ ‘ํ•ฉ๋ถ€๋กœ ๊ตฌ์„ฑ๋˜์—ˆ๋‹ค. ์ด ์ค‘์—๋Š” 43๊ฐœ์˜ CPC ์‹คํ—˜์ฒด๊ฐ€ ํฌํ•จ๋˜์–ด ์žˆ๋‹ค. ์ทจํ•ฉํ•œ ์‹คํ—˜์ฒด๋Š” ๋‹ค์–‘ํ•œ ๋ณ€์ˆ˜์— ๋Œ€ํ•˜์—ฌ ์‹คํ—˜ํ•œ ๊ฒƒ์œผ๋กœ ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ์••์ถ•๊ฐ•๋„($f_{ck}$)๋Š” 22 MPa~150.6 MPa, ๋ณด ๋‹จ๋ฉด์˜ ์œ ํšจ๊นŠ์ด($d$)๋Š” 205 mm~660 mm์ด๋‹ค. ๊ธฐ๋‘ฅ๊ณผ ๋ณด์˜ ๊ฒฝ๊ฐ„๋น„๋Š” 0.80~2.81์ด์—ˆ๋‹ค. ์‹คํ—˜์ฒด์˜ ์žฌ๋ฃŒ ๋ฒ”์œ„๋Š” Table 1์— ์ •๋ฆฌ๋˜์—ˆ๊ณ , ์ถœ์ฒ˜๋Š” ๋ถ€๋ก์˜ ๋ฐ์ดํ„ฐ ์ถœ์ฒ˜์— ๊ธฐ์ˆ ๋˜์—ˆ๋‹ค.

Table 1 150 test specimens

Types

Ranges

$f_{ck}$ (MPa)

Column

22.0~50.6

Beam

22.0~118.8

$d$ (mm)

205~660

$h_{c}$ (mm)

250~762

$l_{b}$/$l_{c}$

0.80~2.81

$f_{y}$ (MPa)

Column

350~718

Beam

285~1,460

$f_{yt}$ (MPa)

Column

306~1,381

Beam

300~1,437

Note: $h_{c}$: section depth of column; $l_{b}$: length of beam; $l_{c}$: heigh of column; $f_{y}$ and $f_{yt}$: tensile strength of longitudinal and transverse steel bars, respectively

์ ‘ํ•ฉ๋ถ€์˜ ํŒŒ๊ดด๋Š” ํฌ๊ฒŒ 3๊ฐ€์ง€ ํŒŒ๊ดด๋ชจ๋“œ๋กœ ๊ตฌ๋ถ„๋œ๋‹ค. โ‘  ๋ณด๊ฐ€ ํœจ ํ•ญ๋ณตํ•˜๊ธฐ ์ „์— ์ ‘ํ•ฉ๋ถ€ ๋‚ด๋ ฅ์ด ์ž‘์•„์ ธ ๋ณด๋Š” ํƒ„์„ฑ ์ƒํƒœ๋ฅผ ์œ ์ง€ํ•˜๋ฉด์„œ ์ ‘ํ•ฉ๋ถ€๊ฐ€ ๋จผ์ € ํŒŒ๊ดด๋˜๋Š” ํ˜•ํƒœ(์ดํ›„ J-ํŒŒ๊ดด), โ‘ก ๋ณด์˜ ์ฃผ์ธ์žฅ์ฒ ๊ทผ์ด ํ•ญ๋ณตํ•˜์—ฌ ์†Œ์„ฑํžŒ์ง€๊ฐ€ ํ˜•์„ฑ ๋œ ์ดํ›„ ์ ‘ํ•ฉ๋ถ€๊ฐ€ ํŒŒ๊ดดํ•˜๋Š” ๊ฒฝ์šฐ(์ดํ›„ BJ-ํŒŒ๊ดด), โ‘ข ๋ณด์˜ ์ดˆ๊ณผ ๊ฐ•๋„๋ณด๋‹ค ์ ‘ํ•ฉ๋ถ€์˜ ๊ณต์นญ ๊ฐ•๋„๊ฐ€ ํฐ ๊ฒฝ์šฐ๋กœ ์ ‘ํ•ฉ๋ถ€์— ํฐ ๋ณ€ํ˜• ์—†์ด ๋ณด์˜ ์†Œ์„ฑํžŒ์ง€๊ฐ€ ํœจํŒŒ๊ดดํ•˜๋Š” ๊ฒฝ์šฐ(์ดํ›„ B-ํŒŒ๊ดด)์ด๋‹ค. ํ•œํŽธ, ACI Committee 352(2002)์—์„œ๋Š” ์ง€์ง„ํ•˜์ค‘์„ ๋ฐ›๋Š” ์ฒ ๊ทผ์ฝ˜ํฌ๋ฆฌํŠธ ๋ณด-๊ธฐ๋‘ฅ ์ ‘ํ•ฉ๋ถ€์˜ ์„ค๊ณ„๋ฅผ ๋น„๋‚ด์ง„ ๋˜๋Š” ์•ฝ์ง„ ๊ตฌ์—ญ(Type 1)๊ณผ ๊ฐ•์ง„ ๊ตฌ์—ญ(Type 2)์œผ๋กœ ๊ตฌ๋ถ„ํ•˜์—ฌ ์„ค๊ณ„ํ•˜๊ณ  ์žˆ๋‹ค. Type 2์˜ ๋ณด-๊ธฐ๋‘ฅ ์ ‘ํ•ฉ๋ถ€๋Š” ๋ณด์— ์†Œ์„ฑํžŒ์ง€๊ฐ€ ๋ฐœ์ƒํ•œ ์ดํ›„ ์ ‘ํ•ฉ๋ถ€๊ฐ€ ํŒŒ๊ดดํ•˜๊ฑฐ๋‚˜(BJ-ํŒŒ๊ดด), ์ ‘ํ•ฉ๋ถ€๊ฐ€ ํƒ„์„ฑ์„ ์œ ์ง€ํ•œ ์ƒํƒœ์—์„œ ๋ณด๋งŒ ํŒŒ๊ดดํ•˜๋Š” ์ ‘ํ•ฉ๋ถ€์ด๋‹ค(B-ํŒŒ๊ดด).

์ˆ˜์ง‘ํ•œ ์‹คํ—˜์ฒด์˜ ํŒŒ๊ดด๋ชจ๋“œ๋ฅผ ์ ‘ํ•ฉ๋ถ€์˜ ์ „๋‹จ๊ฐ•๋„์™€ ๋ณด์˜ ์†Œ์„ฑํžŒ์ง€ ์˜์—ญ์˜ ํœจํ•ญ๋ณต๊ฐ•๋„๋ฅผ ๋น„๊ตํ•˜์—ฌ ํ‰๊ฐ€ํ•˜์˜€๋‹ค. ์ ‘ํ•ฉ๋ถ€์˜ ์ „๋‹จ๊ฐ•๋„๋Š” KCI-17(2017) ์ฝ˜ํฌ๋ฆฌํŠธ ๊ตฌ์กฐ์„ค๊ณ„๊ธฐ์ค€์˜ ์‹ (1)๋กœ ๊ณ„์‚ฐํ•˜์˜€๋‹ค.

(1)
$V_{jn}=\lambda_{j}\sqrt{f_{ck}}A_{j}$

์—ฌ๊ธฐ์„œ, $V_{jn}$๋Š” ์ ‘ํ•ฉ๋ถ€ ์ „๋‹จ ๊ฐ•๋„, $\lambda_{j}$๋Š” ์ ‘ํ•ฉ๋ถ€ ๊ตฌ์†๊ณ„์ˆ˜, $f_{ck}$๋Š” ์ฝ˜ํฌ๋ฆฌํŠธ ์••์ถ•๊ฐ•๋„, $A_{j}$๋Š” ์ ‘ํ•ฉ๋ถ€์˜ ์œ ํšจ๋ฉด์ ์ด๋‹ค.

๋ณด์—์„œ ์ฃผ์ธ์žฅ ์ฒ ๊ทผ์ด ํ•ญ๋ณตํ•  ๋•Œ์˜ ์ ‘ํ•ฉ๋ถ€์˜ ์ˆ˜ํ‰ ์ „๋‹จ๋ ฅ, $V_{jby}$๋ฅผ ์‹ (2)์— ์˜ํ•˜์—ฌ ๊ณ„์‚ฐํ•˜์˜€๋‹ค.

(2)
$V_{jby}=\left(\dfrac{l_{c}}{z_{b}}-1\right)V_{by}\dfrac{l_{b}}{l_{c}}-\dfrac{h_{c}}{z_{b}}V_{by}$

์—ฌ๊ธฐ์„œ, $l_{c}$๋Š” ๊ธฐ๋‘ฅ์˜ ๋†’์ด, $z_{b}$๋Š” ๋ณด์˜ ์ƒ๋ถ€์™€ ํ•˜๋ถ€ ์ฃผ์ฒ ๊ทผ์˜ ์ค‘์‹ฌ๊ฐ„ ๊ฑฐ๋ฆฌ, $l_{b}$๋Š” ๋ณด์˜ ๊ธธ์ด, $h_{c}$๋Š” ๊ธฐ๋‘ฅ ๋‹จ๋ฉด์˜ ๋†’์ด์ด๋‹ค. ๋ณด๊ฐ€ ํ•ญ๋ณตํ•  ๋•Œ์˜ ์ „๋‹จ๋ ฅ $V_{by}$๋Š” ๋ณด ์ธ์žฅ์ฒ ๊ทผ์˜ ํ•ญ๋ณต๊ฐ•๋„๋ฅผ ์ด์šฉํ•˜์—ฌ ๊ณ„์‚ฐํ•˜์˜€๋‹ค.

BJ-ํŒŒ๊ดด ๋˜๋Š” B-ํŒŒ๊ดด๋Š” ๋ชจ๋‘ ๋ณด์— ์†Œ์„ฑํžŒ์ง€๊ฐ€ ํ˜•์„ฑ๋œ ์ดํ›„์— ํŒŒ๊ดด๋˜๋ฏ€๋กœ ์ด๋ฅผ ๋ช…ํ™•ํ•˜๊ฒŒ ๊ตฌ๋ณ„ํ•˜๊ธฐ๋Š” ์–ด๋ ต๋‹ค. ๋”ฐ๋ผ์„œ ์ด ์—ฐ๊ตฌ์—์„œ๋Š” KCI-17(2017) ๊ธฐ์ค€์˜ ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ ์ ‘ํ•ฉ๋ถ€ ์„ค๊ณ„์— ๊ทผ๊ฑฐํ•˜์—ฌ ์ด๋ฅผ ๊ตฌ๋ถ„ํ•˜์˜€๋‹ค. KCI-17 ๊ธฐ์ค€์—์„œ ๋ณด์˜ ๋‚ด๋ ฅ์€ 1.2์˜ ๊ณ„์ˆ˜๋ฅผ ๊ณฑํ•˜์—ฌ $\Sigma M_{c}\ge 6 /5\times\Sigma M_{g}$์— ์˜ํ•ด ๊ณ„์‚ฐํ•œ๋‹ค. ์—ฌ๊ธฐ์„œ, $\Sigma M_{c}$์™€ $\Sigma M_{g}$๋Š” ๊ฐ๊ฐ ์ ‘ํ•ฉ๋ถ€์˜ ์ ‘ํ•ฉ๋ฉด์— ์—ฐ๊ฒฐ๋œ ๊ธฐ๋‘ฅ๋“ค์˜ ์„ค๊ณ„ํœจ๊ฐ•๋„์˜ ํ•ฉ๊ณผ ๋ณด์˜ ์„ค๊ณ„ํœจ๊ฐ•๋„์˜ ํ•ฉ์ด๋‹ค. ์ด๋•Œ ์ ‘ํ•ฉ๋ฉด์—์„œ ๋ณด์˜ ์ข…๋ฐฉํ–ฅ์ฒ ๊ทผ์˜ ์ž‘์šฉ๋ ฅ์€ ํœจ์ธ์žฅ์ฒ ๊ทผ์˜ ์‘๋ ฅ์„ $1.25f_{y}$๋ผ๊ณ  ๊ฐ€์ •ํ•˜์—ฌ ๊ณ„์‚ฐํ•ด์•ผ ํ•œ๋‹ค. ๋”ฐ๋ผ์„œ $1.2\times 1.25 =1.5$๊ฐ€ ๋˜๋ฏ€๋กœ $V_{jn}/V_{jby}\ge 1.5$ ์ด์ƒ์ธ ๋ถ€์žฌ๋ฅผ B-ํŒŒ๊ดด ๋ถ€์žฌ, $1.0\le V_{jn}/V_{jby}<1.5$์ธ ๋ถ€์žฌ๋ฅผ BJ-ํŒŒ๊ดด ๋ถ€์žฌ๋กœ ๊ตฌ๋ถ„ํ•˜์˜€๋‹ค. KCI-17(2017)๋Š” ACI 352R-02(2002) ์ง€์นจ์˜ Type 2์™€ ๋™์ผํ•˜๋ฏ€๋กœ $V_{jn}$๋Š” Type 1์— ํ•ด๋‹นํ•˜๋Š” $\lambda_{j}$๋ฅผ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ์ˆ˜์ง‘ํ•œ 150๊ฐœ ์‹คํ—˜์ฒด ์ค‘์—์„œ J-ํŒŒ๊ดดํ•œ ์‹คํ—˜์ฒด๋Š” 13๊ฐœ์˜€์œผ๋ฉฐ, BJ-ํŒŒ๊ดด ๋˜๋Š” B-ํŒŒ๊ดดํ•œ ์‹คํ—˜์ฒด์˜ ์ˆ˜๋Š” ๊ฐ๊ฐ 60๊ฐœ์™€ 77๊ฐœ์˜€๋‹ค.

์ง€์ง„ํ•˜์ค‘์„ ๋ฐ›๋Š” ๋‚ด๋ถ€ ์ ‘ํ•ฉ๋ถ€๋Š” ๋ถ€์ฐฉํŒŒ๊ดด ๊ฐ€๋Šฅ์„ฑ์ด ๋†’์œผ๋ฏ€๋กœ KCI-17 ๊ธฐ์ค€์—์„œ๋Š” ์ ‘ํ•ฉ๋ถ€ ๋‚ด๋ถ€์˜ ์ฒ ๊ทผ ์ง๊ฒฝ์ด ์‹ (3a, 3b)๋ฅผ ๋งŒ์กฑํ•˜๋„๋ก ๊ทœ์ •ํ•˜๊ณ  ์žˆ๋‹ค. ์ด ๊ธฐ์ค€์— ๊ทผ๊ฑฐํ•˜์—ฌ ์ˆ˜์ง‘ํ•œ ๋ฐ์ดํ„ฐ์˜ ๋ถ€์ฐฉํŒŒ๊ดด ๊ฐ€๋Šฅ์„ฑ์„ ๊ตฌ๋ถ„ํ•˜์˜€๋‹ค.

(3a)
$h / d_{b}\ge 20$ ($f_{y}\le 400$ MPa์ธ ๊ฒฝ์šฐ)
(3b)
$h / d_{b}\ge 25$ ($f_{y}>400$ MPa์ธ ๊ฒฝ์šฐ)

์—ฌ๊ธฐ์„œ, $h$๋Š” ์ข…๋ฐฉํ–ฅ์ฒ ๊ทผ์— ํ‰ํ–‰ํ•œ ๊ธฐ๋‘ฅ ๋ณ€์˜ ๊ธธ์ด์ด๋ฉฐ, $d_{b}$๋Š” ์ ‘ํ•ฉ๋ถ€์— ๋ฐฐ๊ทผ๋œ ๋ณด์˜ ์ฃผ์ฒ ๊ทผ ์ง๊ฒฝ์ด๋‹ค. ์‹ (3a, 3b)๋ฅผ ๋งŒ์กฑํ•œ ์ˆ˜์ง‘ํ•œ ์ ‘ํ•ฉ๋ถ€์˜ ์ˆ˜๋Š” 147๊ฐœ์ด๋ฉฐ, ๋งŒ์กฑํ•˜์ง€ ๋ชปํ•œ ์‹คํ—˜์ฒด๋Š” 3๊ฐœ์˜€๋‹ค. ๋‹ค๋งŒ ๋ถ€์ฐฉํŒŒ๊ดด ๊ฐ€๋Šฅ์„ฑ์ด ์žˆ๋Š” 3๊ฐœ ์‹คํ—˜์ฒด๋„ ์‹คํ—˜์—์„œ๋Š” ์ ‘ํ•ฉ๋ถ€์˜ ์†์ƒ์— ์˜ํ•ด ํŒŒ๊ดด๋œ ๊ฒƒ์ด์—ˆ๊ธฐ์— ๋ถ„์„์— ํฌํ•จํ•˜์˜€๋‹ค.

์ ‘ํ•ฉ๋ถ€์— ๋Œ€ํ•œ ๊ธฐ์กด ์—ฐ๊ตฌ๋ฅผ ์‚ดํŽด๋ณด๋ฉด ๋ณด์™€ ๊ธฐ๋‘ฅ์˜ ๋‚ด๋ ฅ์— ๋”ฐ๋ผ์„œ ์˜ํ–ฅ์„ ๋ฐ›์„ ์ˆ˜ ์žˆ๋‹ค. ๋”ฐ๋ผ์„œ ์ด ์—ฐ๊ตฌ์—์„œ๋Š” $\Sigma M_{c}$์™€ $\Sigma M_{g}$์˜ ๋น„์œจ์„ ๋ถ„์„ํ•˜์˜€๋‹ค. ์ˆ˜์ง‘ํ•œ 150๊ฐœ ์‹คํ—˜์ฒด ์ค‘์—์„œ $\Sigma M_{c}$/$\Sigma M_{g}$๊ฐ€ 1๋ณด๋‹ค ์ž‘์€ ์‹คํ—˜์ฒด๋Š” 52๊ฐœ์˜€๋‹ค. KCI-17 ๊ธฐ์ค€(2017)์˜ ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ๋Š” $\Sigma M_{c}$/$\Sigma M_{g}$์˜ ์ฐจ์ด๋ฅผ ๋ฐ˜์˜ํ•˜์—ฌ ๋ถ„๋ฅ˜ํ•˜์˜€๋‹ค. 150๊ฐœ ์ ‘ํ•ฉ๋ถ€์˜ ๊ณจ์กฐ ํ˜•์‹์„ KCI-17 ๊ธฐ์ค€์— ๊ทผ๊ฑฐํ•˜์—ฌ ์ค‘๊ฐ„๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ์™€ ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ๋กœ ๊ตฌ๋ถ„ํ•˜์˜€๋‹ค. ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ๋Š” $\Sigma M_{c}$/$\Sigma M_{g}$๊ฐ€ 6/5 ์ด์ƒ์ด๋ฉฐ ์ ‘ํ•ฉ๋ถ€ ๋‚ด๋ถ€์˜ ํšก๋ฐฉํ–ฅ ์ฒ ๊ทผ ๊ทœ์ •์ด ์ฝ˜ํฌ๋ฆฌํŠธ ๊ตฌ์กฐ์„ค๊ณ„๊ธฐ์ค€(KCI 2017)์˜ ๋‚ด์ง„์„ค๊ณ„์กฐ๊ฑด์— ๋ถ€ํ•ฉํ•˜๋Š” ์‹คํ—˜์ฒด์ด๋‹ค. 150๊ฐœ ์‹คํ—˜์ฒด ์ค‘์—์„œ 49๊ฐœ ์‹คํ—˜์ฒด๊ฐ€ ํŠน์ˆ˜๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ์— ์†ํ–ˆ์œผ๋ฉฐ, 101๊ฐœ ์‹คํ—˜์ฒด๊ฐ€ ์ค‘๊ฐ„๋ชจ๋ฉ˜ํŠธ๊ณจ์กฐ ์‹คํ—˜์ฒด์— ์†ํ–ˆ๋‹ค. 150๊ฐœ ์‹คํ—˜์ฒด์˜ ํŒŒ๊ดด๋ชจ๋“œ์— ๋Œ€ํ•œ ๊ฒฐ๊ณผ๋ฅผ Table 2์— ์ •๋ฆฌํ•˜์˜€๋‹ค.

Table 2 Types of 150 test specimens

Number of specimens

CPC

PC-Wet

PC-Dry

Types

Internal joints

36

70

17

External joints

7

16

4

Frames

IMRF

27

57

17

SMRF

16

29

4

Failure modes

J-Failure

2

7

4

BJ-Failure

17

31

12

B-Failure

24

48

5

Bond failure

Safe

42

84

21

Unsafe

1

2

0

$\Sigma M_{c}/\Sigma M_{g}$

$\Sigma M_{c}/\Sigma M_{g}\ge 1$

31

57

10

$\Sigma M_{c}/\Sigma M_{g}<1$

12

29

11

Note: IMRF: intermediate moment resisting frame; SMRF: special moment resisting frame

3.2 ์‹คํ—˜์ฒด์˜ ์—ฐ์„ฑ ํ‰๊ฐ€

PC ๊ณจ์กฐ์˜ ๋™๋“ฑ์„ฑ์„ ํ‰๊ฐ€ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ 150๊ฐœ ๋ณด-๊ธฐ๋‘ฅ ์ ‘ํ•ฉ๋ถ€์˜ ๋ณ€์œ„ ์—ฐ์„ฑ๋น„($\mu_{\theta}=\theta_{u}/\theta_{y}$)๋ฅผ ๋ณ€์ˆ˜์— ๋”ฐ๋ผ ๋ถ„๋ฆฌํ•˜์—ฌ ํ‰๊ฐ€ํ•˜์˜€๋‹ค. ํœจํ•ญ๋ณต ์‹œ์˜ ๋ณ€์œ„๋น„($\theta_{y}$)๋Š” Pan๊ณผ Moehle(1989)์˜ ์ œ์•ˆ์— ๊ทผ๊ฑฐํ•˜์—ฌ Fig. 1๊ณผ ๊ฐ™์ด ์ตœ๋Œ€ ํ•˜์ค‘์˜ 66.67 %์™€ ์›์ ์„ ์—ฐ๊ฒฐํ–ˆ์„ ๋•Œ์˜ ๋ณ€์œ„๋น„๋กœ ํ•˜์˜€๋‹ค. ๊ทนํ•œ ๋ณ€์œ„๋น„($\theta_{u}$)๋Š” ๋ถ€์žฌ๊ฐ€ ์ตœ๋Œ€ ํ•˜์ค‘์— ๋„๋‹ฌํ•œ ์ดํ›„์— ํ•˜์ค‘์ด 95 %๊นŒ์ง€ ๊ฐ์†Œํ–ˆ์„ ๋•Œ์˜ ๋ณ€์œ„๋น„๋กœ ํ•˜์˜€๋‹ค. ์ผ๋ฐ˜์ ์œผ๋กœ $\theta_{u}$๋Š” ์ตœ๋Œ€ ํ•˜์ค‘์ด 80 % ๋˜๋Š” 85 %์— ๋„๋‹ฌํ–ˆ์„ ๋•Œ์˜ ๊ฐ’์„ ๊ธฐ์ค€์œผ๋กœ ํ•˜์ง€๋งŒ, ์‹คํ—˜ ๋ฐ์ดํ„ฐ์˜ ์ด๋ ฅ๊ณก์„ ์—์„œ ํ•˜์ค‘์ด 85 %๊นŒ์ง€ ๋–จ์–ด์ง„ ๋ฐ์ดํ„ฐ๋Š” ๋งŽ์ง€ ์•Š์•˜๋‹ค. ์ด ๊ฒฝ์šฐ์— ํ•˜์ค‘์˜ ๊ฐ์†Œ ๊ฒฝํ–ฅ์„ ์—ฐ์žฅํ•˜์—ฌ $\theta_{u}$๋ฅผ ์ •ํ•˜๊ธฐ๋„ ํ•˜์ง€๋งŒ ์ด๊ฒƒ์ด ์ •ํ™•ํ•˜๊ฒŒ $\theta_{u}$๋ฅผ ํ‰๊ฐ€ํ•œ๋‹ค๊ณ  ํ•  ์ˆ˜ ์—†๋‹ค. ๋˜ํ•œ ์ด ๋…ผ๋ฌธ์—์„œ๋Š” ํ˜„์žฅํƒ€์„ค ์ฝ˜ํฌ๋ฆฌํŠธ์™€ PC์˜ ์ƒ๋Œ€์„ฑ์„ ํ‰๊ฐ€ํ•˜๋Š” ๊ฒƒ์„ ๋ชฉ์ ์œผ๋กœ ํ•˜๋ฏ€๋กœ ํ•˜์ค‘์ด 95 %๊นŒ์ง€ ๊ฐ์†Œํ–ˆ์„ ๋•Œ์˜ ๋ณ€์œ„๋น„๋ฅผ $\theta_{u}$๋กœ ํ•˜์˜€๋‹ค. Fig. 2๋Š” ์ ‘ํ•ฉ๋ถ€ ๊ฐ•๋„์™€ ๋ณด์˜ ํœจํ•ญ๋ณต ์‹œ์˜ ๊ฐ•๋„๋น„($V_{jn}/V_{jby}$)์— ์˜ํ•ด ๊ตฌ๋ถ„๋œ ์‹คํ—˜์ฒด์˜ ์—ฐ์„ฑ์„ ๋น„๊ตํ•˜์˜€๋‹ค. Fig. 2(a)๋Š” ๊ทนํ•œ ๋ณ€์œ„๋น„($\theta_{u}$)๋ฅผ ๋‚˜ํƒ€๋‚ด๋ฉฐ, Fig. 2(b)๋Š” ๋ณ€์œ„ ์—ฐ์„ฑ๋น„($\mu_{\theta}$)๋ฅผ ๋‚˜ํƒ€๋‚ธ๋‹ค. ์‹คํ—˜์ฒด๋Š” CPC ์‹คํ—˜์ฒด, ์Šต์‹ ์ ‘ํ•ฉ PC ์‹คํ—˜์ฒด(PC-wet), ๊ฑด์‹ ์ ‘ํ•ฉ PC ์‹คํ—˜์ฒด(PC-dry)๋กœ ๊ตฌ๋ถ„๋˜์—ˆ๋‹ค. Fig. 2(a)์—์„œ $\theta_{u}$๋Š” $V_{jn}/V_{jby}$์˜ ๋ณ€ํ™”์™€ ๊ด€๊ณ„์—†์ด 0.01์—์„œ 0.07 ์‚ฌ์ด์˜ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค. Fig. 2(b)์—์„œ $\theta_{u}$๋Š” $V_{jn}/V_{jby}$๊ฐ€ ์ฆ๊ฐ€ํ•˜๋ฉด ์†Œํญ ์ฆ๊ฐ€ํ•จ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. $V_{jn}/V_{jby}$๊ฐ€ 1๋ณด๋‹ค ์ž‘์„ ๊ฒฝ์šฐ์— $\theta_{u}$๋Š” ์•ฝ 2์˜€์ง€๋งŒ, $V_{jn}/V_{jby}$๊ฐ€ 2์ผ ๋•Œ $\theta_{u}$๋Š” ์•ฝ 6๊นŒ์ง€ ์ฆ๊ฐ€ํ•˜์˜€๋‹ค. ๋‹ค๋งŒ Fig. 2์—์„œ $\theta_{u}$์™€ $\mu_{\theta}$๋Š” ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ์ข…๋ฅ˜(CPC ๋˜๋Š” PC)์— ๋ฌด๊ด€ํ•˜๊ฒŒ ๊ฑฐ์˜ ์ผ์ •ํ•œ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค.

Fig. 1 Definition of drift ratio
../../Resources/KCI/JKCI.2022.34.6.633/fig1.png
Fig. 2 Ductility ratio vs. $V_{jn}/V_{jby}$
../../Resources/KCI/JKCI.2022.34.6.633/fig2.png

Fig. 3์€ ๊ธฐ๋‘ฅ๊ณผ ๋ณด์˜ ํœจ๊ฐ•๋„ ๋น„($\Sigma M_{c}/\Sigma M_{g}$)์— ์˜ํ•ด ๊ตฌ๋ถ„๋œ ์‹คํ—˜์ฒด์˜ ์—ฐ์„ฑ์„ ๋น„๊ตํ•˜์˜€๋‹ค. Fig. 3(a)๋Š” ๊ทนํ•œ ๋ณ€์œ„๋น„($\theta_{u}$)๋ฅผ ๋‚˜ํƒ€๋‚ด๋ฉฐ, Fig. 3(b)๋Š” ๋ณ€์œ„ ์—ฐ์„ฑ๋น„($\mu_{\theta}$)๋ฅผ ๋‚˜ํƒ€๋‚ธ๋‹ค. $\Sigma M_{c}/\Sigma M_{g}$์™€ ์—ฐ์„ฑ์˜ ๊ด€๊ณ„๋Š” $V_{jn}/V_{jby}$์™€ ์—ฐ์„ฑ์˜ ๊ด€๊ณ„์™€ ๊ฑฐ์˜ ์œ ์‚ฌํ•œ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค. ์ฆ‰, $\theta_{u}$๋Š” $\Sigma M_{c}/\Sigma M_{g}$์˜ ๋ณ€ํ™”์™€ ๊ด€๊ณ„์—†์ด ๊ฑฐ์˜ ์ผ์ •ํ•˜์˜€์ง€๋งŒ $\mu_{\theta}$๋Š” $\Sigma M_{c}/\Sigma M_{g}$๊ฐ€ ์ฆ๊ฐ€ํ•˜๋ฉด ์†Œํญ ์ฆ๊ฐ€ํ•˜์˜€๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๊ทธ ๊ฒฝํ–ฅ์€ $V_{jn}/V_{jby}$๊ฐ€ $\mu_{\theta}$์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ๊ณผ ๊ฐ™์ด ๋šœ๋ ทํ•˜์ง€๋Š” ์•Š์•˜๋‹ค. Fig. 3์—์„œ๋„ Fig. 2์˜ ๊ฒฐ๊ณผ์™€ ๋™์ผํ•˜๊ฒŒ $\theta_{u}$์™€ $\mu_{\theta}$๋Š” ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ์ข…๋ฅ˜(CPC ๋˜๋Š” PC)์— ๋ฌด๊ด€ํ•˜๊ฒŒ ์ผ์ •ํ•œ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค.

Fig. 3 Ductility ratio vs. $\Sigma M_{c}/\Sigma M_{g}$
../../Resources/KCI/JKCI.2022.34.6.633/fig3.png

4. PC ๊ณจ์กฐ์˜ ๋ถ€์žฌ ์„ฑ๋Šฅ ํ‰๊ฐ€

Fig. 2์™€ Fig. 3์—์„œ $V_{jn}/V_{jby}$์™€ $\Sigma M_{c}/\Sigma M_{g}$์— ๋Œ€ํ•˜์—ฌ ๊ทนํ•œ ๋ณ€์œ„๋น„($\theta_{u}$)์™€ ์—ฐ์„ฑ๋น„($\mu_{\theta}$)๋Š” ๋šœ๋ ทํ•œ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด์ง€ ์•Š์•˜๋‹ค. ๋”ฐ๋ผ์„œ ์ด ์—ฐ๊ตฌ์—์„œ๋Š” ACI 374.1-05 ์ง€์นจ๊ณผ โ€œํ˜„์žฅํƒ€์„ค ๋™๋“ฑํ˜• PC ๊ตฌ์กฐ์„ค๊ณ„์ง€์นจโ€(AIJ 2002)๊ณผ ์œ ์‚ฌํ•˜๊ฒŒ ๋‹ค์Œ ์กฐ๊ฑด์— ์˜ํ•˜์—ฌ ๋ถ€์žฌ์˜ ์„ฑ๋Šฅ์„ ํ‰๊ฐ€ํ•˜์˜€๋‹ค.

โ‘  ๊ฐ•๋„ ์ €๊ฐ๋ฅ : ๋ณ€์œ„๋น„๋ฅผ 4๋‹จ๊ณ„(2.0 %, 2.5 %, 3.0 %, 3.5 %)๋กœ ๊ตฌ๋ถ„ํ•˜๊ณ  ๊ฐ๊ฐ์˜ ๋ณ€์œ„๋น„์˜ ์ฒซ ๋ฒˆ์งธ ๊ฐ€๋ ฅ๊ณผ ๋‘ ๋ฒˆ์งธ ๊ฐ€๋ ฅ์—์„œ์˜ ๊ฐ•๋„ ์ €๊ฐ๋ฅ (Fig. 4(a) ์ฐธ์กฐ)

โ‘ก ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„: ๋ณ€์œ„๋น„๋ฅผ 4๋‹จ๊ณ„(2.0 %, 2.5 %, 3.0 %, 3.5 %)๋กœ ๊ตฌ๋ถ„ํ•˜๊ณ  ๋‘ ๋ฒˆ์งธ ๊ฐ€๋ ฅ์—์„œ์˜ ์—๋„ˆ์ง€ ์†Œ์‚ฐ์œจ(Fig. 4(b) ์ฐธ์กฐ). $\theta$๋Š” ACI 374.1-05 ์ง€์นจ์— ๊ทผ๊ฑฐํ•˜์—ฌ ์ž„์˜์˜ ๋ณ€์œ„๋น„์—์„œ ์™„์ „์—๋„ˆ์ง€ ์†Œ์‚ฐ [์ •๋ถ€๋ฐฉํ–ฅ ๋ชจ๋ฉ˜ํŠธ($M_{1}+$$M_{2}$)$\times$์ •๋ถ€๋ฐฉํ–ฅ ๋ณ€์œ„๋น„($\theta_{1}+\theta_{2}$)]์— ๋Œ€ํ•œ ์ด๋ ฅ๊ณก์„ ์˜ ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„๋ฅผ ๋‚˜ํƒ€๋‚ธ๋‹ค.

โ‘ข ์ดˆ๊ธฐ ๊ฐ•์„ฑ: ํœจํ•ญ๋ณต ์‹œ์˜ ๋ณ€์œ„๋น„($\theta_{y}$)์™€ ์‹œ์ž‘์ ์„ ์—ฐ๊ฒฐํ•˜์—ฌ ์ธก์ •

Fig. 5๋Š” 4๋‹จ๊ณ„ ๋ณ€์œ„๋น„($\theta$)์—์„œ ์ฒซ ๋ฒˆ์งธ ๊ฐ€๋ ฅ ์‹œ์˜ ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•œ ์‹คํ—˜์ฒด์˜ ๋น„์œจ์„ ๋‚˜ํƒ€๋‚ธ๋‹ค. ์ฆ‰, ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•œ ์‹คํ—˜์ฒด์˜ ์ˆ˜๋ฅผ ์ „์ฒด ์‹คํ—˜์ฒด์˜ ์ˆ˜๋กœ ๋‚˜๋ˆˆ ๊ฐ’์ด๋‹ค. ๊ทธ๋ฆผ์—์„œ $\theta$๊ฐ€ 2.0 %์ผ ๋•Œ CPC ์‹คํ—˜์ฒด ์ค‘์—์„œ ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œ($V/V_{\max}<1.0$)ํ•œ ์‹คํ—˜์ฒด๋Š” 5 %์— ์ง€๋‚˜์ง€ ์•Š์•˜๋‹ค. ๋ฐ˜๋ฉด PC ์‹คํ—˜์ฒด ์ค‘์—์„œ๋Š” 12 %์˜ ์‹คํ—˜์ฒด์˜ ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•˜์˜€๋‹ค. $\theta$๊ฐ€ ์ฆ๊ฐ€ํ•˜๋ฉด์„œ ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•œ CPC์™€ PC ์‹คํ—˜์ฒด์˜ ๋น„์œจ์ด ์ฆ๊ฐ€ํ•˜์˜€๋‹ค. $\theta$๊ฐ€ 3.0 %์ผ ๋•Œ CPC ์‹คํ—˜์ฒด ์ค‘์—์„œ 44 %์˜ ์‹คํ—˜์ฒด์˜ ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•˜์˜€์œผ๋ฉฐ, PC ์‹คํ—˜์ฒด ์ค‘์—์„œ๋Š” 43 %์˜ ์‹คํ—˜์ฒด๊ฐ€ ๊ฐ•๋„ ๊ฐ์†Œ๋ฅผ ๋ณด์˜€๋‹ค. ๋‘ ๊ทธ๋ฃน์˜ ์‹คํ—˜์ฒด๋ฅผ ๋น„๊ตํ•˜๋ฉด CPC ์‹คํ—˜์ฒด๋ณด๋‹ค ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•˜๋Š” PC ์‹คํ—˜์ฒด์˜ ์ˆ˜๊ฐ€ ๋งŽ์•˜๋‹ค.

Fig. 4 Structural capacity of beam-column joints
../../Resources/KCI/JKCI.2022.34.6.633/fig4.png
Fig. 5 Specimen number ratio, $V/V_{\max}$ at first cycle
../../Resources/KCI/JKCI.2022.34.6.633/fig5.png
Fig. 6 Specimen number ratio, $V/V_{\max}$ at second cycle
../../Resources/KCI/JKCI.2022.34.6.633/fig6.png

Fig. 6์€ ๋™์ผํ•œ ๋ณ€์œ„๋น„($\theta$)์—์„œ ๋ฐ˜๋ณตํ•˜์ค‘์„ ๋‘ ๋ฒˆ ๊ฐ€๋ ฅํ–ˆ์„ ๋•Œ ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•œ ์‹คํ—˜์ฒด์˜ ๋น„์œจ์„ ๋‚˜ํƒ€๋‚ธ๋‹ค. ์ฒซ ๋ฒˆ์งธ ๊ฐ€๋ ฅ์— ๋น„ํ•˜์—ฌ ๋‘ ๋ฒˆ์งธ ๊ฐ€๋ ฅ์‹œ์— ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•œ ์‹คํ—˜์ฒด์˜ ์ˆ˜๊ฐ€ ์ฆ๊ฐ€ํ•˜์˜€๋‹ค. $\theta$๊ฐ€ 2.0 %์ผ ๋•Œ CPC ์‹คํ—˜์ฒด์˜ 33 %๊ฐ€ ๊ฐ์†Œํ•˜์˜€์œผ๋ฉฐ, PC ์‹คํ—˜์ฒด์˜ 38 %๊ฐ€ ๊ฐ์†Œํ•˜์˜€๋‹ค. ํŠนํžˆ $\theta$๊ฐ€ 2.5 %๋ฅผ ์ดˆ๊ณผํ•  ๋•Œ๋Š” ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•œ ์‹คํ—˜์ฒด์˜ ์ˆ˜๊ฐ€ ์ ˆ๋ฐ˜ ์ด์ƒ์ด์—ˆ๋‹ค.

Fig. 7์€ ๊ฐ ๋ณ€์œ„๋น„์—์„œ ๋ฐœ์ƒํ•œ ๊ฐ•๋„ ๊ฐ์†Œ์œจ์˜ ํ‰๊ท ๊ฐ’์„ ๋‚˜ํƒ€๋‚ธ๋‹ค. ์˜ˆ๋ฅผ ๋“ค์–ด ์ฒซ ๋ฒˆ์งธ ๊ฐ€๋ ฅ์‹œ์— ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•œ ์‹คํ—˜์ฒด๊ฐ€ ์žˆ์œผ๋ฉด ์ด ์‹คํ—˜์ฒด์˜ ํšกํ•˜์ค‘($V$)์„ ์ตœ๋Œ€ ํ•˜์ค‘($V_{\max}$)์œผ๋กœ ๋‚˜๋ˆ„์—ˆ๋‹ค. Fig. 7์€ ๋ชจ๋“  ์‹คํ—˜์ฒด์— ๋Œ€ํ•œ $V/V_{\max}$์˜ ํ‰๊ท ๊ฐ’์ด๋‹ค. ๊ทธ๋ฆผ์—์„œ $\theta$๊ฐ€ 2.0 %์ผ ๋•Œ CPC ์‹คํ—˜์ฒด์™€ PC ์‹คํ—˜์ฒด์˜ ๊ฐ•๋„ ๊ฐ์†Œ์˜ ํ‰๊ท ๊ฐ’์€ ๋งค์šฐ ์ ๋‹ค๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ $\theta$๊ฐ€ ์ฆ๊ฐ€ํ•˜๋ฉด์„œ ๊ฐ•๋„ ๊ฐ์†Œ์˜ ํ‰๊ท ๊ฐ’์€ ์ ์ฐจ ์ฆ๊ฐ€ํ•˜์˜€๋‹ค. CPC ์‹คํ—˜์ฒด์˜ ๊ฒฝ์šฐ์—๋Š” ์ฒซ ๋ฒˆ์งธ ๊ฐ€๋ ฅ ์‹œ์— $\theta$๊ฐ€ 2.5, 3.0, 3.5 %์ผ ๋•Œ ๊ฐ•๋„ ๊ฐ์†Œ๋Š” ๊ฐ๊ฐ 4 %, 6 %, 16 %์˜€๋‹ค. PC ์‹คํ—˜์ฒด์˜ ๊ฒฝ์šฐ์—๋Š” ๊ฐ๊ฐ 5 %, 13 %, 20 %๋กœ CPC๋ณด๋‹ค ์ปธ๋‹ค. ๋‘ ๋ฒˆ์งธ ๊ฐ€๋ ฅ ์‹œ์˜ ๊ฐ์†Œ์œจ์„ ์‚ดํŽด๋ณด๋ฉด $\theta$๊ฐ€ 2.5, 3.0, 3.5 %์ผ ๋•Œ CPC ์‹คํ—˜์ฒด์˜ ๊ฐ•๋„ ๊ฐ์†Œ๋Š” ๊ฐ๊ฐ 9 %, 12 %, 24 %์˜€์œผ๋ฉฐ, PC ์‹คํ—˜์ฒด์˜ ๊ฒฝ์šฐ์—๋Š” ๊ฐ๊ฐ 14 %, 19 %, 32 %๋กœ ํฌ๊ฒŒ ์ฆ๊ฐ€ํ•˜์˜€๋‹ค.

Fig. 8์€ ๊ฐ ๋ณ€์œ„๋น„์—์„œ ์ฒซ ๋ฒˆ์งธ ๊ฐ€๋ ฅ๊ณผ ๋‘ ๋ฒˆ์งธ ๊ฐ€๋ ฅ์—์„œ ๋ฐœ์ƒํ•œ ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„์˜ ํ‰๊ท ๊ฐ’์„ ๋‚˜ํƒ€๋‚ธ๋‹ค. ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„ $\theta$๋Š” ACI 374.1-05 ์ง€์นจ๊ณผ ๋™์ผํ•œ ๋ฐฉ๋ฒ•์œผ๋กœ ์ธก์ •ํ•˜์˜€๋‹ค. ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„๋Š” $\theta$์™€ ๋ฌด๊ด€ํ•˜๊ฒŒ ๊ฑฐ์˜ ์ผ์ •ํ•˜๊ฑฐ๋‚˜ ์†Œํญ ๊ฐ์†Œํ•˜์˜€๋‹ค. CPC ์‹คํ—˜์ฒด์˜ ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„๋Š” PC ์‹คํ—˜์ฒด์˜ ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„๋ณด๋‹ค ์•ฝ 2~3 % ์ปธ๋‹ค.

Fig. 7 Strength decrease rate
../../Resources/KCI/JKCI.2022.34.6.633/fig7.png
Fig. 8 Energy dissipation ratio
../../Resources/KCI/JKCI.2022.34.6.633/fig8.png

5. PC ๊ณจ์กฐ์˜ ๋™๋“ฑ์„ฑ ํ‰๊ฐ€

5.1 PC ๋ถ€์žฌ์˜ ์ƒ๋Œ€ ์„ฑ๋Šฅ

๊ณจ์กฐ์˜ ๊ฑฐ๋™์€ ๋ถ€์žฌ์˜ ๊ฐ•๋„ ์ €๊ฐ, ์—๋„ˆ์ง€ ์†Œ์‚ฐ, ๊ฐ•์„ฑ๊ณผ ๋ฐ€์ ‘ํ•œ ๊ด€๋ จ์ด ์žˆ๋‹ค. PC์˜ ๋™๋“ฑ์„ฑ์— ๋Œ€ํ•œ ๊ธฐ์ค€์„ ์ •ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์ด๋“ค ๊ฐ’์˜ ๋ณ€ํ™”๋ฅผ ์‚ดํŽด๋ณด์•„์•ผ ํ•œ๋‹ค.

Fig. 9๋Š” ๋™์ผํ•œ ๋ณ€์œ„๋น„์—์„œ ๋‘ ๋ฒˆ์งธ ๊ฐ€๋ ฅ์‹œ์˜ ํšกํ•˜์ค‘($V_{2nd}$)์„ ์ฒซ ๋ฒˆ์งธ ๊ฐ€๋ ฅ์‹œ์˜ ํšกํ•˜์ค‘($V_{1st}$)์œผ๋กœ ๋‚˜๋ˆˆ ๊ฐ’์˜ ํ‰๊ท ์ด๋‹ค. ๊ทธ๋ฆผ์—์„œ $\theta$๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ์„œ ๊ฐ•๋„๊ฐ์†Œ๋น„๋Š” ์ ์  ์ปค์ง€๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. $\theta$๊ฐ€ 2.0 %์ผ ๋•Œ ์•ฝ 9 %์˜ ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•˜์˜€์ง€๋งŒ, 3.5 %์ผ ๋•Œ๋Š” ์•ฝ 14 %์˜ ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œํ•˜์˜€๋‹ค. ๋‹ค๋งŒ CPC ์‹คํ—˜์ฒด์™€ PC ์‹คํ—˜์ฒด์˜ ๊ฐ•๋„๊ฐ์†Œ๋น„๋Š” ๊ฑฐ์˜ ๋™์ผํ•˜์˜€๋‹ค. $V_{2nd}/V_{1st}$๋ฅผ ํŠน์ˆ˜ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ์™€ ์ค‘๊ฐ„ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ๋กœ ๊ตฌ๋ถ„ํ•˜์—ฌ Fig. 9(b)์™€ 9(c)์— ์ œ์‹œํ•˜์˜€๋‹ค. ๊ณจ์กฐ์— ๋”ฐ๋ผ์„œ $V_{2nd}/V_{1st}$๋Š” ๋ฐ˜๋Œ€ ๊ฒฐ๊ณผ๊ฐ€ ๋‚˜ํƒ€๋‚ฌ์œผ๋ฉฐ, ํŠน์ˆ˜ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ ์‹คํ—˜์ฒด์—์„œ๋Š” $\theta$๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ์„œ CPC ์‹คํ—˜์ฒด์˜ ๊ฐ’์ด PC ์‹คํ—˜์ฒด๋ณด๋‹ค ๋‚ฎ์•˜์ง€๋งŒ, ์ค‘๊ฐ„ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ์—์„œ๋Š” CPC ์‹คํ—˜์ฒด์˜ ๊ฐ’์ด PC ์‹คํ—˜์ฒด๋ณด๋‹ค ๋†’์•˜๋‹ค. ์ด ๊ฒฐ๊ณผ์—์„œ $V_{2nd}/V_{1st}$๋Š” ๊ณจ์กฐ์˜ ํ˜•์‹๋ณด๋‹ค๋Š” ๋ณ€์œ„๋น„์˜ ํฌ๊ธฐ์— ๋”ฐ๋ผ์„œ ๋‹ฌ๋ผ์ง€๋Š” ๊ฒƒ์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค.

Fig. 10์€ Fig. 4์˜ ๋ฐฉ๋ฒ•์— ์˜ํ•ด ๊ณ„์‚ฐํ•œ ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„์˜ ํ‰๊ท ๊ฐ’์„ ํŠน์ˆ˜ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ์™€ ์ค‘๊ฐ„ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ๋กœ ๊ตฌ๋ถ„ํ•˜์—ฌ ์ œ์‹œํ•˜์˜€๋‹ค. ๋‘ ๊ณจ์กฐ์— ๋Œ€ํ•˜์—ฌ ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„๋Š” $\theta$๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ์„œ ์ฆ๊ฐ€ํ•˜์˜€๋‹ค. CPC ์‹คํ—˜์ฒด์˜ ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„๊ฐ€ PC ์‹คํ—˜์ฒด๋ณด๋‹ค ๋†’์•˜์ง€๋งŒ, ๊ทธ ์ฐจ์ด๋Š” ํฌ์ง€ ์•Š์•˜๋‹ค. ๋˜ํ•œ ํŠน์ˆ˜ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ์™€ ์ค‘๊ฐ„ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ์—์„œ ์œ ์‚ฌํ•œ ์—๋„ˆ์ง€ ์†Œ์‚ฐ ๊ฒฝํ–ฅ์ด ๋‚˜ํƒ€๋‚ฌ๋‹ค.

Fig. 11์€ ํŠน์ˆ˜ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ์™€ ์ค‘๊ฐ„ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ ์‹คํ—˜์ฒด์˜ ์ดˆ๊ธฐ ์ƒ๋Œ€๊ฐ•์„ฑ์„ ๋‚˜ํƒ€๋‚ธ๋‹ค. ์ดˆ๊ธฐ ์ƒ๋Œ€๊ฐ•์„ฑ์ด๋ž€ ๋™์ผํ•œ ์กฐ๊ฑด์˜ ์‹คํ—˜๊ตฐ์— CPC ์‹คํ—˜์ฒด์™€ PC ์‹คํ—˜์ฒด๊ฐ€ ํ•จ๊ป˜ ์žˆ์„ ๊ฒฝ์šฐ์— PC ์‹คํ—˜์ฒด์˜ ์ดˆ๊ธฐ๊ฐ•์„ฑ์„ CPC ์‹คํ—˜์ฒด์˜ ์ดˆ๊ธฐ๊ฐ•์„ฑ์œผ๋กœ ๋‚˜๋ˆˆ ๊ฐ’์„ ์˜๋ฏธํ•œ๋‹ค. ๊ทธ๋ฆผ์—์„œ PC ์‹คํ—˜์ฒด์˜ ์ดˆ๊ธฐ๊ฐ•์„ฑ์€ CPC ์‹คํ—˜์ฒด์˜ ์ดˆ๊ธฐ๊ฐ•์„ฑ์€ ์•ฝ 60 %์—์„œ 140 % ์‚ฌ์ด์— ์žˆ๋‹ค๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. ์ด๋Ÿฌํ•œ ๊ฐ•์„ฑ์ฐจ์ด๋Š” ๊ณจ์กฐ์˜ ํ˜•์‹๋ณด๋‹ค๋Š” ์ ‘ํ•ฉ์ƒ์„ธ์™€ ๊ฐ™์€ PC ๋ถ€์žฌ์˜ ์กฐ๊ฑด์— ์˜ํ•ด ์˜ํ–ฅ์„ ๋ฐ›์•˜๋‹ค.

Fig. 9 $V_{2nd}/V_{1st}$ vs. $\theta$
../../Resources/KCI/JKCI.2022.34.6.633/fig9.png
Fig. 10 $\beta$ vs. $\theta$
../../Resources/KCI/JKCI.2022.34.6.633/fig10.png
Fig. 11 Initial stiffness ratio
../../Resources/KCI/JKCI.2022.34.6.633/fig11.png

5.2 PC ๊ณจ์กฐ์˜ ๋™๋“ฑ์„ฑ

Fig. 5์—์„œ Fig. 11๊นŒ์ง€ 150๊ฐœ ์‹คํ—˜์ฒด์— ๋Œ€ํ•œ ๋ถ„์„ ๊ฒฐ๊ณผ๋ฅผ ๋‹ค์Œ๊ณผ ๊ฐ™์ด ์š”์•ฝํ•  ์ˆ˜ ์žˆ๋‹ค.

โ‘  ๊ฐ•๋„ ๊ฐ์†Œ์œจ: ๋ณ€์œ„๋น„ 2 %๊นŒ์ง€๋Š” CPC ๋ถ€์žฌ์™€ PC ๋ถ€์žฌ์˜ ๊ฐ•๋„ ์ฐจ์ด๋Š” ๊ฑฐ์˜ ๋ฐœ์ƒํ•˜์ง€ ์•Š์•˜์œผ๋ฉฐ, 3.5 %์— ๋„๋‹ฌํ–ˆ์„ ๋•Œ CPC ๋ถ€์žฌ์™€ PC ๋ถ€์žฌ์˜ ์ตœ๋Œ€ ๊ฐ•๋„ ์ฐจ์ด๋Š” ์•ฝ 6 %์˜€๋‹ค.

โ‘ก ๋™์ผํ•œ ๋ณ€์œ„๋น„์—์„œ ๊ฐ€๋ ฅ ํšŸ์ˆ˜์— ์˜ํ•œ ๊ฐ•๋„ ๊ฐ์†Œ์œจ: ๋ณ€์œ„๋น„ 2.0 %์—์„œ $V_{2nd}/V_{1st}$๋Š” ์•ฝ 91 %์˜€์œผ๋ฉฐ, 3.5 %์—์„œ ์•ฝ 86 %์˜€๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ CPC ๋ถ€์žฌ์™€ PC ๋ถ€์žฌ์˜ ๊ฐ•๋„๊ฐ์†Œ๋น„๋Š” ๊ฑฐ์˜ ๋™์ผํ•˜์˜€๋‹ค.

โ‘ข ์—๋„ˆ์ง€ ์†Œ์‚ฐ: CPC ๋ถ€์žฌ์™€ PC ๋ถ€์žฌ์˜ ์—๋„ˆ์ง€ ์†Œ์‚ฐ๋น„์˜ ์ฐจ์ด๋Š” ์ตœ๋Œ€ ์•ฝ 3 %์˜€๋‹ค.

โ‘ฃ ๊ฐ•์„ฑ: CPC ๋ถ€์žฌ์™€ PC ๋ถ€์žฌ์˜ ์ดˆ๊ธฐ๊ฐ•์„ฑ์˜ ์ฐจ์ด๋Š” ์•ฝ 60 %์—์„œ 140 %์˜€๋‹ค.

์ด ๋…ผ๋ฌธ์—์„œ๋Š” ์œ„์—์„œ ๋ถ„์„ํ•œ ์‹คํ—˜์ฒด์˜ ๊ฐ•๋„, ์—๋„ˆ์ง€ ์†Œ์‚ฐ, ๊ฐ•์„ฑ, ์—ฐ์„ฑ ๋“ฑ์„ ๊ทผ๊ฑฐ๋กœ PC ๋ชจ๋ฉ˜ํŠธ ์ €ํ•ญ ๊ณจ์กฐ์˜ ๋™๋“ฑ์„ฑ ํ‰๊ฐ€ ๊ธฐ์ค€์„ ๊ฒ€ํ† ํ•˜์˜€๋‹ค. ์ฒ ๊ทผ์ฝ˜ํฌ๋ฆฌํŠธ ๊ตฌ์กฐ๋ฌผ์˜ ๊ฒฝ์šฐ์—๋Š” ์ค‘๊ฐ„ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ์™€ ํŠน์ˆ˜ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ๋ฅผ ๋ณ€์œ„๋น„๋ฅผ ๊ธฐ์ค€์œผ๋กœ ๊ตฌ๋ถ„ํ•˜๊ณ  ์žˆ์ง€๋Š” ์•Š๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๋ฏธ๊ตญ ๊ฐ•๊ตฌ์กฐ์„ค๊ณ„๊ธฐ์ค€(AISC 2016)์—์„œ๋Š” ์ค‘๊ฐ„ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ์˜ ๋ณด-๊ธฐ๋‘ฅ ์ ‘ํ•ฉ๋ถ€์˜ ์ตœ์†Œ ๋ณ€์œ„๋น„๋ฅผ 2.0 %๋กœ ๊ทœ์ •ํ•˜๊ณ  ์žˆ๋‹ค. ๋”ฐ๋ผ์„œ ์ด ๋…ผ๋ฌธ์—์„œ๋„ PC ์ค‘๊ฐ„ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ์˜ ๋™๋“ฑ์„ฑ ํ‰๊ฐ€ ๊ธฐ์ค€์„ $\theta$๊ฐ€ 2.0 %์ธ ๊ฒฝ์šฐ์˜ ๊ตฌ์กฐ์„ฑ๋Šฅ์œผ๋กœ ํ•˜์˜€๋‹ค. ํŠน์ˆ˜ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ์— ๋Œ€ํ•ด์„œ๋Š” ACI 374.1- 05 ์ง€์นจ๊ณผ ๋™์ผํ•˜๊ฒŒ 3.5 %๋ฅผ ๊ธฐ์ค€์œผ๋กœ ํ•˜์˜€๋‹ค.

๊ธฐ์กด ๋™๋“ฑ์„ฑ ํ‰๊ฐ€ ๊ธฐ์ค€๊ณผ 150๊ฐœ ์‹คํ—˜์ฒด์— ๋Œ€ํ•œ ๋ถ„์„ ๊ฒฐ๊ณผ๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ PC ๊ณจ์กฐ๊ฐ€ CPC ๊ณจ์กฐ์™€ ๋™์ผํ•œ ์„ฑ๋Šฅ์„ ๊ฐ–๊ธฐ ์œ„ํ•ด์„œ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์€ ์กฐ๊ฑด์ด ํ•„์š”ํ•  ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

(1) ๊ธฐ๋ณธ ๋™๋“ฑ์„ฑ๋Šฅ

โ‘  PC ๋ถ€์žฌ์˜ ๊ฐ•์„ฑ, ๊ฐ•๋„, ์—๋„ˆ์ง€ ์†Œ์‚ฐ์˜ ์—ญํ•™์  ํŠน์„ฑ์ด CPC ๋ถ€์žฌ์˜ ์„ฑ๋Šฅ๊ณผ ๋™๋“ฑํ•˜๊ฒŒ ๋˜๊ธฐ ์œ„ํ•˜์—ฌ PC ์ ‘ํ•ฉ๋ถ€์˜ ์ ์ ˆํ•œ ์œ„์น˜๋ฅผ ์„ ์ •ํ•ด์•ผ ํ•˜๊ณ , CPC ๋ถ€์žฌ์™€ ๋™๋“ฑํ•œ ๊ตฌ์กฐ ์„ฑ๋Šฅ์„ ํ™•๋ณดํ•ด์•ผ ํ•œ๋‹ค.

โ‘ก PC ๋ถ€์žฌ๋Š” CPC ๋ถ€์žฌ์˜ ์„ฑ๋Šฅ๊ณผ ๋™๋“ฑํ•œ ๊ท ์—ดํญ, ์ฒ˜์ง, ์ง„๋™์— ๋Œ€ํ•œ ์‚ฌ์šฉ์„ฑ์„ ํ™•๋ณดํ•ด์•ผ ํ•œ๋‹ค.

โ‘ข PC ๋ถ€์žฌ์˜ ์ ‘ํ•ฉ๋ฉด์—์„œ๋Š” ํ•œ๊ณ„ ์ด์ƒ์˜ ์ž”๋ฅ˜๋ณ€ํ˜•์ด ๋ฐœ์ƒํ•ด์„œ๋Š” ์•ˆ ๋œ๋‹ค.

(2) ์‹คํ—˜์— ์˜ํ•œ ๋™๋“ฑ์„ฑ ํ‰๊ฐ€์˜ ์กฐ๊ฑด

โ‘  ๋ชจ๋ฉ˜ํŠธ ์ €ํ•ญ ๊ณจ์กฐ์˜ ๋ณด์™€ ๊ธฐ๋‘ฅ์ด ๊ต์ฐจํ•˜๋Š” ๋ถ€์œ„์— ๋Œ€ํ•ด ์ตœ์†Œ ํ•˜๋‚˜์˜ ๋ชจ๋“ˆ์„ ์‹คํ—˜ํ•ด์•ผ ํ•œ๋‹ค.

โ‘ก ์‹คํ—˜์ฒด๋Š” ์‹ค์ œ ๊ตฌ์กฐ๋ฌผ์˜ ๊ฑฐ๋™์„ ๋ฐ˜์˜ํ•  ์ˆ˜ ์žˆ์„ ๋งŒํผ์˜ ํฌ๊ธฐ๋กœ ํ•ด์•ผ ํ•˜๋ฉฐ, 1/3 ๋ฏธ๋งŒ์œผ๋กœ ์ถ•์†Œํ•ด์„œ๋Š” ์•ˆ ๋œ๋‹ค.

โ‘ข ํ•˜์ค‘์€ ๋™์ผ ๋ณ€์œ„์—์„œ 2ํšŒ ์ด์ƒ ๋ฐ˜๋ณตํ•˜์ค‘์„ ๊ฐ€๋ ฅ ํ•ด์•ผ ํ•œ๋‹ค. ์ดˆ๊ธฐ ๋ณ€์œ„๋น„๋Š” ์„ ํ˜•ํƒ„์„ฑ ์‘๋‹ต ๋ฒ”์œ„ ๋‚ด์— ์žˆ์–ด์•ผ ํ•˜๋ฉฐ, ์ด์–ด์ง€๋Š” ๋ณ€์œ„๋น„๋Š” ์ด์ „ ๋ณ€์œ„๋น„์˜ 1.25๋ฐฐ ์ด์ƒ์ด๋ฉฐ 2.0๋ฐฐ ์ดํ•˜๊ฐ€ ๋˜์–ด์•ผ ํ•œ๋‹ค.

(3) ์ค‘๊ฐ„ ๋ชจ๋ฉ˜ํŠธ ์ €ํ•ญ ๊ณจ์กฐ์™€ ํŠน์ˆ˜ ๋ชจ๋ฉ˜ํŠธ ์ €ํ•ญ ๊ณจ์กฐ๋Š” ๋ณ€์œ„๋น„๊ฐ€ ๊ฐ๊ฐ 2.0 %์™€ 3.5 %์ผ ๋•Œ, ๋‹ค์Œ ์กฐ๊ฑด์„ ๋งŒ์กฑํ•ด์•ผ ํ•œ๋‹ค.

โ‘  PC ์‹คํ—˜์ฒด์˜ ํœจํ•ญ๋ณต๊ฐ•๋„๋Š” ์„ค๊ณ„ํœจํ•ญ๋ณต๊ฐ•๋„ ์ด์ƒ์ด ๋˜์–ด์•ผ ํ•˜๋ฉฐ, ํ—ˆ์šฉ ๋ณ€์œ„๋น„์— ๋„๋‹ฌํ•˜๊ธฐ ์ „์— ์‹คํ—˜์ฒด์˜ ํšก๊ฐ•๋„๋Š” ๊ณต์นญํšก๊ฐ•๋„ ์ด์ƒ์ด ๋˜์–ด์•ผ ํ•œ๋‹ค.

โ‘ก ํ˜„์žฅํƒ€์„ค ์ฝ˜ํฌ๋ฆฌํŠธ ์‹คํ—˜์ฒด์™€ PC ์‹คํ—˜์ฒด์˜ ๋‚ด๋ ฅ ์ฐจ์ด๋Š” 10 % ์ด๋‚ด๊ฐ€ ๋˜์–ด์•ผ ํ•œ๋‹ค.

โ‘ข 2๋ฒˆ์งธ ๋ฐ˜๋ณตํ•˜์ค‘์„ ๋ฐ›์„ ๋•Œ์˜ PC ์‹คํ—˜์ฒด์˜ ๊ฐ•๋„๋Š” ๋‚ด๋ ฅ์˜ 80 % ์ด์ƒ์ด ๋˜์–ด์•ผ ํ•œ๋‹ค.

โ‘ฃ 2๋ฒˆ์งธ ๋ฐ˜๋ณตํ•˜์ค‘์„ ๋ฐ›์„ ๋•Œ์˜ PC ์‹คํ—˜์ฒด์˜ ๊ฐ•์„ฑ๊ณผ ์—๋„ˆ์ง€ ์†Œ์‚ฐ์€ ํ˜„์žฅํƒ€์„ค ์ฝ˜ํฌ๋ฆฌํŠธ ์‹คํ—˜์ฒด์˜ ๊ฐ•์„ฑ๊ณผ ์—๋„ˆ์ง€ ์†Œ์‚ฐ์˜ 90 % ์ด์ƒ์ด ๋˜์–ด์•ผ ํ•œ๋‹ค.

6. ๊ฒฐ ๋ก 

์ค‘๊ณ ์ธต์˜ PC ๊ตฌ์กฐ๋ฌผ์„ ์„ค๊ณ„ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” PC ๊ตฌ์กฐ๋ฌผ์˜ ๋‚ด์ง„์„ค๊ณ„ ์กฐ๊ฑด์ด ํ•„์š”ํ•˜๋‹ค. KCI-17 ๊ธฐ์ค€์˜ ๋‚ด์ง„์„ค๊ณ„์—์„œ๋Š” PC ๊ตฌ์กฐ๋ฌผ์ด ์ถฉ๋ถ„ํ•œ ๊ฐ•๋„์™€ ์ธ์„ฑ์„ ๋ณด์œ ํ•˜๊ณ  ์žˆ์„ ๋•Œ CPC ๊ตฌ์กฐ๋ฌผ๊ณผ ๋™๋“ฑํ•˜๊ฒŒ ์„ค๊ณ„ํ•˜๋„๋ก ๊ทœ์ •ํ•˜๊ณ  ์žˆ๋‹ค. ๋‹ค๋งŒ PC ๊ตฌ์กฐ๋ฌผ์˜ ๋™๋“ฑ์„ฑ ํ‰๊ฐ€์— ๋Œ€ํ•œ ๊ตฌ์ฒด์ ์ธ ์กฐ๊ฑด์„ ์ œ์‹œํ•˜๊ณ ๋Š” ์žˆ์ง€ ์•Š๋‹ค. ์ด ์—ฐ๊ตฌ์—์„œ๋Š” 150๊ฐœ์˜ ๋ชจ๋ฉ˜ํŠธ ์ €ํ•ญ ๊ณจ์กฐ์˜ ๋ณด-๊ธฐ๋‘ฅ ์ ‘ํ•ฉ๋ถ€ ์‹คํ—˜ ๊ฒฐ๊ณผ๋ฅผ ๋ถ„์„ํ•˜๊ณ  ๋™๋“ฑ์„ฑ ํ‰๊ฐ€๋ฅผ ์œ„ํ•œ ๊ธฐ๋ณธ ์กฐ๊ฑด์„ ์ œ์‹œํ•˜์˜€๋‹ค. ๋ถ„์„ํ•œ ๋‚ด์šฉ์˜ ์ฃผ์š” ๊ฒฐ๋ก ์€ ๋‹ค์Œ๊ณผ ๊ฐ™๋‹ค.

1) PC ๋ถ€์žฌ์˜ ์ ‘ํ•ฉ๋ถ€๊ฐ€ ํ•ฉ๋ฆฌ์ ์œผ๋กœ ์„ค๊ณ„๋˜์—ˆ์„ ๊ฒฝ์šฐ์— PC ๋ถ€์žฌ์˜ ๊ตฌ์กฐ์„ฑ๋Šฅ์€ CPC ๋ถ€์žฌ์™€ ๊ฑฐ์˜ ์œ ์‚ฌํ•˜์˜€๋‹ค. ๋”ฐ๋ผ์„œ PC ์ค‘๊ฐ„ ๋ชจ๋ฉ˜ํŠธ ์ €ํ•ญ ๊ณจ์กฐ์™€ PC ํŠน์ˆ˜ ๋ชจ๋ฉ˜ํŠธ ๊ณจ์กฐ์˜ ๋™๋“ฑ์„ฑ์€ ๋ณ€์œ„๋น„๊ฐ€ ๊ฐ๊ฐ 2 %์™€ 3.5 %์ผ ๋•Œ์˜ ์กฐ๊ฑด์„ ๊ธฐ์ค€์œผ๋กœ ํ‰๊ฐ€ํ•  ์ˆ˜ ์žˆ์„ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

2) ๋ฐ˜๋ณตํ•˜์ค‘์„ ๋ฐ›๋Š” PC ๋ถ€์žฌ์˜ ๊ฐ•๋„์ €๊ฐ๋ฅ ์€ ๋ณ€์œ„๋น„๊ฐ€ 2 %์ผ ๋•Œ๋Š” CPC ๋ถ€์žฌ์˜ ์ €๊ฐ๋ฅ ๊ณผ ๊ฑฐ์˜ ๋™์ผํ•˜์˜€์ง€๋งŒ, ๋ณ€์œ„๋น„๊ฐ€ 3.5 %์ผ ๋•Œ๋Š” ์•ฝ 6 % ๋” ์ปธ๋‹ค. ๋ณ€์œ„๋น„ 3.5 %์—์„œ๋„ PC ๋ถ€์žฌ์˜ ์ฒซ ๋ฒˆ์งธ ๊ฐ€๋ ฅ ์‹œ์˜ ํ‰๊ท  ๊ฐ•๋„๋Š” ์ตœ๋Œ€ ๊ฐ•๋„์˜ 80 % ์ด์ƒ์ด์—ˆ๋‹ค.

3) CPC ๋ถ€์žฌ์˜ ์—๋„ˆ์ง€ ์†Œ์‚ฐ์œจ์ด PC ๋ถ€์žฌ์˜ ์—๋„ˆ์ง€ ์†Œ์‚ฐ์œจ๋ณด๋‹ค ์ปธ์ง€๋งŒ, ๊ทธ ์ฐจ์ด๋Š” ์ตœ๋Œ€ 3 %๋กœ ํฌ์ง€ ์•Š์•˜๋‹ค.

4) ๋™์ผํ•œ ๋ณ€์œ„๋น„์—์„œ ์ฒซ ๋ฒˆ์งธ ๊ฐ€๋ ฅ ์‹œ์˜ ๊ฐ•๋„์™€ ๋‘ ๋ฒˆ์งธ ๊ฐ€๋ ฅ์‹œ์˜ ๊ฐ•๋„ ์ฐจ์ด๋Š” PC ๋ถ€์žฌ์™€ CPC ๋ถ€์žฌ๊ฐ€ ๊ฑฐ์˜ ๋™์ผํ•˜์˜€๋‹ค.

5) ์ดˆ๊ธฐ ์ƒ๋Œ€๊ฐ•์„ฑ์€ ๊ณจ์กฐ์˜ ํ˜•์‹๋ณด๋‹ค๋Š” ์ ‘ํ•ฉ์ƒ์„ธ์™€ ๊ฐ™์€ PC ๋ถ€์žฌ์˜ ์กฐ๊ฑด์— ์˜ํ•ด ์˜ํ–ฅ์„ ๋ฐ›์•˜๋‹ค.

๊ฐ์‚ฌ์˜ ๊ธ€

๋ณธ ์—ฐ๊ตฌ๋Š” ๊ตญํ† ๊ตํ†ต๋ถ€๊ฐ€ ์ง€์›ํ•˜๋Š” ๊ตญํ† ๊ตํ†ต๊ณผํ•™๊ธฐ์ˆ ์ง„ํฅ์›์˜ โ€œOff-Site Construction ๊ธฐ๋ฐ˜ ๊ณต๋™์ฃผํƒ ์ƒ์‚ฐ์‹œ์Šคํ…œ ํ˜์‹ ๊ธฐ์ˆ  ๊ฐœ๋ฐœโ€ ์—ฐ๊ตฌ๋น„ ์ง€์›์œผ๋กœ ์ˆ˜ํ–‰๋˜์—ˆ์œผ๋ฉฐ(๊ณผ์ œ๋ฒˆํ˜ธ: 200 RPS-B158109-01), ์ด์— ๊ฐ์‚ฌ๋“œ๋ฆฝ๋‹ˆ๋‹ค.

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