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TCXDVN

Tiu chun xy dng Vit nam

TCXDVN 375 : 2006Xut bn ln 1

Thit k cng trnh chu ng tDesign of structures for earthquake resistance

Phn 1: Quy nh chung, tc ng ng t v quy nh i vi kt cu nh

H ni - 2006

TCXDVN 375 : 2006

mc lc

Li ni u 1. 1.1. 1.1.1. 1.1.2. 1.2. 1.2.1. 1.2.2. 1.3. 1.4. 1.5. 1.5.1. 1.5.2. 1.6. 1.6.1. 1.6.2. 1.6.3. 1.6.4. 1.6.5. 1.6.6. 1.6.7. 1.6.8. 1.6.9. 1.7. 2. 2.1. 2.2. 2.2.1. 2.2.2. 2.2.3. 2.2.4. 3. 3.1. 3.1.1. 3.1.2. 3.2. 3.2.1. 3.2.2.

................................................................................................................................................. 1

Tng qut ........................................................................................................................................ 3 Phm vi p dng............................................................................................................................... 3 Phm vi p dng ca tiu chun: Thit k cng trnh chu ng t............................................... 3 Phm vi p dng ca phn 1 ........................................................................................................... 3 Cc ti liu tham kho v tiu chun ............................................................................................... 4 Cc tiu chun tham kho chung .................................................................................................... 4 Nhng Quy chun v Tiu chun tham kho khc ......................................................................... 5 Cc gi thit...................................................................................................................................... 5 S phn bit gia cc nguyn tc v cc quy nh p dng ........................................................... 5 Thut ng v nh ngha................................................................................................................... 6 Thut ng chung............................................................................................................................... 6 Cc thut ng khc c s dng trong tiu chun ........................................................................ 6 K hiu .............................................................................................................................................. 8 Tng qut.......................................................................................................................................... 8 Cc k hiu khc c s dng trong chng 2 v chng 3.......................................................... 8 Cc k hiu khc c s dng trong chng 4............................................................................... 9 Cc k hiu khc c s dng trong chng 5............................................................................. 10 Cc k hiu khc c s dng trong chng 6............................................................................. 15 Cc k hiu khc c s dng trong chng 7............................................................................. 16 Cc k hiu khc c s dng trong chng 8............................................................................. 18 Cc k hiu khc c s dng trong chng 9............................................................................. 18 Cc k hiu khc c s dng trong chng 10........................................................................... 19 n v SI ......................................................................................................................................... 20 Yu cu v tnh nng v cc tiu ch cn tun theo ................................................................ 21 Nhng yu cu c bn ................................................................................................................... 21 Cc tiu ch cn tun theo.............................................................................................................. 22 Tng qut........................................................................................................................................ 22 Trng thi cc hn.......................................................................................................................... 23 Trng thi hn ch h hng ........................................................................................................... 24 Cc bin php c th...................................................................................................................... 24 iu kin nn t v tc ng ng t.................................................................................... 25 iu kin nn t............................................................................................................................ 25 Tng qut........................................................................................................................................ 25 Nhn dng cc loi nn t............................................................................................................ 25 Tc ng ng t.......................................................................................................................... 27 Cc vng ng t ......................................................................................................................... 27 Biu din c bn ca tc ng ng t........................................................................................ 28 i

3.2.3. 3.2.4. 4. 4.1. 4.1.1. 4.2. 4.2.1. 4.2.2. 4.2.3. 4.2.4. 4.2.5. 4.3. 4.3.1. 4.3.2. 4.3.3. 4.3.4. 4.3.5. 4.3.6. 4.4. 4.4.1. 4.4.2. 4.4.3. 5. 5.1. 5.1.1. 5.1.2. 5.2. 5.2.1. 5.2.2. 5.2.3. 5.2.4. 5.3. 5.3.1. 5.3.2. 5.3.3. 5.4. 5.4.1. 5.4.2. 5.4.3. 5.5. 5.5.1. 5.5.2. ii

Nhng cch biu din khc ca tc ng ng t....................................................................... 34 Cc t hp tc ng ng t vi cc tc ng khc.................................................................... 35 Thit k nh................................................................................................................................... 37 Tng qut........................................................................................................................................ 37 Phm vi p dng............................................................................................................................. 37 Cc c trng ca cng trnh chu ng t .................................................................................. 37 Nhng nguyn tc c bn ca thit k c s................................................................................. 37 Cc cu kin khng chn chnh v ph ......................................................................................... 39 Tiu ch v tnh u n ca kt cu.............................................................................................. 40 Cc h s t hp ca tc ng thay i......................................................................................... 44 Mc v h s tm quan trng.................................................................................................... 45 Phn tch kt cu ............................................................................................................................ 45 M hnh ........................................................................................................................................... 45 Hiu ng xon ngu nhin ............................................................................................................. 46 Cc phng php phn tch ........................................................................................................... 47 Tnh ton chuyn v ........................................................................................................................ 59 B phn phi kt cu........................................................................................................................ 60 Cc bin php b sung i vi khung c khi xy chn ............................................................... 62 Kim tra an ton ............................................................................................................................. 65 Tng qut........................................................................................................................................ 65 Trng thi cc hn.......................................................................................................................... 65 Hn ch h hng ............................................................................................................................ 70 Nhng quy nh c th cho kt cu btng.............................................................................. 72 Tng qut........................................................................................................................................ 72 Phm vi p dng............................................................................................................................. 72 Thut ng v nh ngha................................................................................................................. 72 Quan nim thit k ......................................................................................................................... 74 Kh nng tiu tn nng lng v cc cp do kt cu.................................................................. 74 Loi kt cu v h s ng x.......................................................................................................... 75 Tiu ch thit k............................................................................................................................... 78 Kim tra mc an ton ................................................................................................................ 82 Thit k theo EN 1992-1-1 ............................................................................................................. 82 Tng qut........................................................................................................................................ 82 Vt liu ............................................................................................................................................ 82 H s ng x................................................................................................................................... 82 Thit k cho trng hp cp do kt cu trung bnh...................................................................... 83 Vt liu v kch thc hnh hc....................................................................................................... 83 H qu tc ng thit k ................................................................................................................ 84 Kim tra v cu to theo trng thi cc hn .................................................................................. 89 Thit k cho trng hp cp do kt cu cao.............................................................................. 100 Vt liu v kch thc hnh hc..................................................................................................... 100 H qu tc ng thit k .............................................................................................................. 102

5.5.3. 5.6. 5.6.1. 5.6.2. 5.6.3. 5.7. 5.8. 5.8.1. 5.8.2 5.8.3. 5.8.4. 5.9. 5.10. 5.11. 5.11.1 5.11.2. 5.11.3. 6. 6.1. 6.1.1 6.1.2 6.1.3 6.2. 6.3. 6.3.1 6.3.2 6.4. 6.5. 6.5.1 6.5.2 6.5.3 6.5.4 6.5.5 6.6. 6.6.1 6.6.2 6.6.3 6.6.4 6.7. 6.7.1 6.7.2 6.7.3 6.7.4 6.8. 6.8.1 6.8.2

Kim tra theo trng thi cc hn v cu to ................................................................................ 104 Cc yu cu v neo v mi ni .................................................................................................... 115 Tng qut...................................................................................................................................... 115 Neo ct thp ................................................................................................................................. 115 Ni cc thanh ct thp.................................................................................................................. 117 Thit k v cu to cc cu kin khng chn ph....................................................................... 118 Cc b phn ca mng btng.................................................................................................... 119 Phm vi......................................................................................................................................... 119 Dm ging v dm ging mng ................................................................................................... 120 Mi ni cc cu kin thng ng vi dm mng hoc tng ...................................................... 120 Cc v i cc btng c ti ch ............................................................................................... 121 nh hng cc b do tng chn bng khi xy hoc btng ................................................... 121 Yu cu i vi tm cng bng btng........................................................................................ 122 Kt cu btng c sn................................................................................................................ 123 Tng qut...................................................................................................................................... 123 Mi ni cc cu kin c sn ....................................................................................................... 127 Cu kin........................................................................................................................................ 128 Nhng quy nh c th cho kt cu thp ................................................................................ 132 Tng qut...................................................................................................................................... 132 Phm vi p dng .................................................................................................................. 132 Cc quan nim thit k ........................................................................................................ 132 Kim tra an ton.............................................................................................................. 133 Vt liu .......................................................................................................................................... 133 Dng kt cu v h s ng x...................................................................................................... 135 Cc dng kt cu ................................................................................................................. 135 H s ng x ........................................................................................................................ 139 Phn tch kt cu .......................................................................................................................... 140 Cc tiu ch thit k v quy nh cu to cho mi loi kt cu c kh nng tiu tn nng lng140 Tng qut ............................................................................................................................. 140 Cc tiu ch thit k cho kt cu c kh nng tiu tn nng lng ...................................... 140 Cc quy nh thit k cho nhng cu kin c kh nng tiu tn nng lng lm vic chu nn hoc un .............................................................................................................................. 141 Cc quy nh thit k cho cc b phn hoc cu kin chu ko........................................... 141 Cc quy nh thit k cho nhng lin kt trong vng tiu tn nng lng............................ 141 Cc quy nh c th cho thit k khung chu mmen .................................................................. 142 Cc tiu ch thit k.............................................................................................................. 142 Dm ..................................................................................................................................... 142 Ct ....................................................................................................................................... 143 Lin kt dm - ct................................................................................................................. 145 Thit k v cc quy nh cu to cho khung vi h ging ng tm........................................... 146 Tiu ch thit k .................................................................................................................... 146 Php phn tch ..................................................................................................................... 147 Cc thanh ging cho .......................................................................................................... 148 Dm v ct ........................................................................................................................... 148 Thit k v cc quy nh cu to cho khung c h ging lch tm............................................. 149 Cc tiu ch thit k.............................................................................................................. 149 Cc on ni khng chn .................................................................................................... 150 iii

6.8.3 6.8.4 6.9. 6.10. 6.10.1 6.10.2 6.10.3 6.11. 7. 7.1 7.1.2 7.1.2 7.1.3 7.2 7.2.1 7.2.2 7.2.3 7.3 7.3.1 7.3.2 7.4 7.4.1 7.4.2 7.5 7.5.1 7.5.2 7.5.3 7.5.4 7.6 7.6.1 7.6.2 7.6.3 7.6.4 7.6.5 7.6.6 7.7 7.7.1 7.7.2 7.7.3 7.7.4 7.7.5 7.8 7.8.1 7.8.2 7.8.3 7.8.4 7.9 7.9.1 7.9.2 iv

Cc cu kin khng c on ni khng chn ...................................................................... 153 Lin kt ca cc on ni khng chn................................................................................. 154 Cc quy nh thit k cho kt cu kiu con lc ngc................................................................. 155 Cc quy nh thit k i vi kt cu thp c li btng hoc vch btng v i vi khung chu mmen kt hp vi h ging ng tm hoc tng chn ........................................................... 155 Kt cu c li btng hoc vch btng .............................................................................. 155 Khung chu mmen kt hp vi h ging ng tm ............................................................. 155 Khung chu mmen kt hp vi tng chn ......................................................................... 156 Qun l thit k v thi cng .......................................................................................................... 156 Nhng quy nh c th cho kt cu lin hp thp - btng.................................................. 157 Tng qut ............................................................................................................................. 157 Phm vi p dng .................................................................................................................. 157 Cc quan nim thit k ........................................................................................................ 157 Kim tra an ton.............................................................................................................. 158 Vt liu ................................................................................................................................. 159 Btng.................................................................................................................................. 159 Ct thp trong btng .......................................................................................................... 159 Kt cu thp ......................................................................................................................... 159 Dng kt cu v h s ng x.............................................................................................. 159 Dng kt cu ........................................................................................................................ 159 H s ng x ........................................................................................................................ 161 Phn tch kt cu.................................................................................................................. 162 Phm vi ................................................................................................................................ 162 cng ca tit din ........................................................................................................... 162 Cc tiu ch thit k v quy nh cu to cho mi loi kt cu c kh nng tiu tn nng lng..... 163 Tng quan ............................................................................................................................ 163 Cc tiu ch thit k i vi kt cu c kh nng tiu tn nng lng.................................. 163 bn do ca cc vng tiu tn nng lng..................................................................... 163 Cc quy nh cu to cho lin kt lin hp trong vng tiu tn nng lng ......................... 164 Cc quy nh cho cu kin ................................................................................................... 165 Tng qut ............................................................................................................................. 165 Dm thp lin hp vi bn ................................................................................................... 169 Chiu rng hu hiu ca bn ............................................................................................... 171 Ct lin hp c bao bc hon ton ................................................................................. 172 Cu kin c bc btng mt phn ................................................................................... 176 Ct thp nhi btng............................................................................................................ 177 Cc quy nh c th cho thit k khung chu mmen........................................................... 177 Cc tiu ch ring ................................................................................................................. 177 Php phn tch ..................................................................................................................... 178 Cc quy nh cho dm v ct............................................................................................... 178 Lin kt dm ct................................................................................................................ 179 iu kin b qua c trng lin hp ca dm vi bn .................................................... 179 Cc quy nh thit k v cu to cho khung lin hp vi ging ng tm ........................... 179 Cc tiu ch c th................................................................................................................ 179 Phng php phn tch ........................................................................................................ 179 Cc cu kin ging cho...................................................................................................... 179 Dm v ct ........................................................................................................................... 180 Cc quy nh thit k v cu to cho khung lin hp vi ging lch tm............................. 180 Cc tiu ch ring ................................................................................................................. 180 Php phn tch ..................................................................................................................... 180

7.9.3 7.9.4 7.10 7.10.1 7.10.2 7.10.3 7.10.4 7.10.5 7.11 7.12 8. 8.1 8.1.1 8.1.2 8.1.3 8.2 8.3 8.4 8.5 8.5.1 8.5.2 8.5.3 8.6 8.7 9. 9.1 9.2 9.2.1 9.2.2 9.2.3 9.2.4 9.3 9.4 9.5 9.5.1 9.5.2 9.5.3 9.5.4 9.6 9.7 9.7.1 9.7.2

on ni............................................................................................................................... 180 Cu kin khng cha on ni khng chn ......................................................................... 181 Cc quy nh thit k v cu to cho h kt cu to bi vch cng bng btng ct thp lin hp vi cc cu kin thp chu lc ....................................................................................... 181 Cc tiu ch .......................................................................................................................... 181 Php phn tch ..................................................................................................................... 183 Cc quy nh cu to cho tng lin hp thuc cp do kt cu trung bnh DCM.............. 183 Cc quy nh cu to cho dm ni thuc cp do kt cu trung bnh DCM ........................ 184 Cc quy nh cu to cho cp do kt cu cao DCH........................................................... 184 Cc quy nh thit k v cu to cho vch cng lin hp dng tm thp bc btng ......... 184 Kim sot thit k v thi cng .............................................................................................. 185 Nhng quy nh c th cho kt cu g.................................................................................... 186 Tng qut ............................................................................................................................. 186 Phm vi p dng .................................................................................................................. 186 Cc nh ngha ..................................................................................................................... 186 Cc quan nim thit k ........................................................................................................ 186 Vt liu v cc c trng ca vng tiu tn nng lng....................................................... 187 Cp do kt cu v h s ng x......................................................................................... 188 Phn tch kt cu.................................................................................................................. 189 Cc quy nh cu to ........................................................................................................... 190 Tng qut ............................................................................................................................. 190 Nhng quy nh cu to cho lin kt .................................................................................... 190 Cc quy nh cu to cho tm cng nm ngang.................................................................. 190 Kim tra an ton.............................................................................................................. 191 Kim sot thit k v thi cng .............................................................................................. 191 Nhng quy nh c th cho kt cu xy.................................................................................. 193 Phm vi p dng .................................................................................................................. 193 Vt liu v kiu lin kt ........................................................................................................ 193 Cc loi vin xy .................................................................................................................. 193 Cng nh nht ca vin xy.......................................................................................... 193 Va xy ................................................................................................................................ 193 Kiu xp vin xy ................................................................................................................. 193 Cc loi cng trnh v h s ng x ..................................................................................... 194 Phn tch kt cu.................................................................................................................. 195 Tiu ch thit k v quy nh thi cng ................................................................................... 196 Tng qut ............................................................................................................................. 196 Cc yu cu b sung cho khi xy khng c ct thp tho mn Phn 1 ca tiu chun ny ............................................................................................................................................. 197 Cc yu cu b sung cho khi xy b hn ch bin dng .................................................... 197 Cc yu cu b sung cho khi xy c ct thp.................................................................... 198 Kim tra an ton................................................................................................................... 199 Cc quy nh cho nh xy n gin................................................................................... 199 Tng qut ............................................................................................................................. 199 Cc quy nh ........................................................................................................................ 199 v

10 10.1 10.2 10.3 10.4 10.5 10.5.1 10.5.2 10.5.3 10.5.4 10.5.5 10.6 10.7 10.8 10.9 10.9.1 10.9.2 10.9.3 10.9.4 10.9.5 10.9.6 10.10

Cch chn y ............................................................................................................................ 202 Phm vi p dng .................................................................................................................. 202 Cc nh ngha ..................................................................................................................... 202 Cc yu cu c bn ............................................................................................................. 204 Cc tiu ch cn tun theo.................................................................................................... 204 Cc iu khon thit k chung............................................................................................. 205 Cc iu khon chung lin quan n thit b ....................................................................... 205 Kim sot cc chuyn ng khng mong mun .................................................................. 205 Kim sot cc chuyn ng nn vi sai do ng t............................................................. 205 Kim sot chuyn v tng i vi nn t v cc cng trnh xung quanh........................... 206 Thit k c s cng trnh c cch chn y ..................................................................... 206 Tc ng ng t ............................................................................................................... 206 H s ng x ........................................................................................................................ 207 Cc c trng ca h cch chn.......................................................................................... 207 Phn tch kt cu.................................................................................................................. 207 Tng qut ............................................................................................................................. 207 Phn tch tuyn tnh tng ng......................................................................................... 208 Phn tch tuyn tnh n gin............................................................................................... 209 Phn tch tuyn tnh n gin ha theo dng dao ng....................................................... 211 Phn tch theo lch s thi gian ............................................................................................ 212 Cc b phn phi kt cu ...................................................................................................... 212 Kim tra an ton theo trng thi cc hn ........................................................................ 212

Ph lc A (tham kho) Ph phn ng chuyn v n hi......................................................................... 214 Ph lc B (tham kho) Xc nh chuyn v mc tiu i vi phn tch tnh phi tuyn (y dn)............. 216 Ph lc C (bt buc) Thit k bn ca dm lin hp thp btng ti lin kt ................................... 220 Ph lc D (tham kho) Cc thut ng v nh ngha ............................................................................... 231 Ph lc E (tham kho) Cc k hiu .......................................................................................................... 241 Ph lc F Mc v h s tm quan trng........................................................................................ 244 Ph lc G Phn cp, phn loi cng trnh xy dng ........................................................................... 246 Ph lc H Bn phn vng gia tc nn lnh th vit nam............................................................... 257 Ph lc I Bng phn vng gia tc nn theo a danh hnh chnh..................................................... 259 Ph lc K Bng chuyn i t nh gia tc nn sang cp ng t................................................... 279

vi

Li ni u

TCXDVN 375:2006: Thit k cng trnh chu ng t c bin son trn c s chp nhn Eurocode 8: Design of structures for earthquake resistance c b sung hoc thay th cc phn mang tnh c th Vit Nam. Eurocode 8 c 6 phn: EN1998 - 1: Quy nh chung, tc ng ng t v quy nh i vi kt cu nh; EN1998 - 2: Quy nh c th cho cu; EN1998 - 3: Quy nh cho nh gi v gia cng khng chn nhng cng trnh hin hu; EN1998 - 4: Quy nh c th cho sil, b cha, ng ng; EN1998 - 5: Quy nh c th cho nn mng, tng chn v nhng vn a k thut; EN1998 - 6: Quy nh c th cho cng trnh dng thp, dng ct, ng khi. Trong ln ban hnh ny mi cp n cc iu khon i vi nh v cng trnh tng ng vi cc phn ca Eurocode 8 nh sau: - Phn 1 tng ng vi EN1998 - 1; - Phn 2 tng ng vi EN1998 - 5; Cc phn b sung hoc thay th cho ni dung Phn 1: - Ph lc F : - Ph lc G : - Ph lc H : - Ph lc I : - Ph lc K : Mc v h s tm quan trng Phn cp, phn loi cng trnh xy dng Bn phn vng gia tc nn lnh th Vit Nam Bng Phn vng gia tc nn theo a danh hnh chnh Bng chuyn i t nh gia tc nn sang cp ng t.

Cc tiu chun tham kho chung trch dn iu 1.2.1 cha c thay th bng cc tiu chun hin hnh ca Vit Nam, v cn m bo tnh ng b gia cc tiu chun trong h thng tiu chun Chu u. H thng tiu chun Vit Nam tip cn h thng tiu chun Chu u s ln lt ban hnh cc tiu chun trch dn ny. Bn phn vng gia tc nn lnh th Vit Nam l kt qu ca ti c lp cp Nh nc. Nghin cu d bo ng t v dao ng nn Vit Nam do Vin Vt l a cu thit lp v chu trch nhim php l c Hi ng Khoa hc cp Nh nc nghim thu nm 2005. Bn s dng trong tiu chun c tin cy v php l tng ng l mt phin bn c th ca bn cng tn c chnh l theo kin ngh trong bin bn nh gi ca Hi ng nghim thu Nh nc. Trong bn phn vng gia tc, nh gia tc nn tham chiu agR trn lnh th Vit Nam c biu th bng cc ng ng tr. Gi tr agR gia hai ng ng tr c xc nh theo nguyn tc ni suy tuyn tnh. nhng vng c th c tranh chp v gia tc nn, gi tr agR do Ch u t quyt nh.

1

T nh gia tc nn agR c th chuyn i sang cp ng t theo thang MSK-64, thang MM hoc cc thang phn bc khc, khi cn p dng cc tiu chun thit k chu ng t khc nhau. Theo gi tr gia tc nn thit k ag = I.agR, chia thnh ba trng hp ng t - ng t mnh ag 0,08g, phi tnh ton v cu to khng chn - ng t yu 0,04g ag < 0,08g, ch cn p dng cc gii php khng chn c gim nh - ng t rt yu ag < 0,04g, khng cn thit k khng chn Trong Eurocode 8 kin ngh dng hai dng ng cong ph, ng cong ph dng 1 dng cho nhng vng c cng chn ng Ms 5,5, ng cong ph dng 2 dng cho nhng vng c cng chn ng Ms < 5,5. Trong tiu chun s dng ng cong ph dng 1 v phn ln cc vng pht sinh ng t ca Vit Nam c cng chn ng Ms 5,5. Khng thit k chu ng t nh nhau i vi mi cng trnh m cng trnh khc nhau thit k chu ng t khc nhau. Ty theo mc tm quan trng ca cng trnh ang xem xt p dng h s tm quan trng I thch hp. Trng hp c th c tranh chp v mc tm quan trng, gi tr I do ch u t quyt nh. TCXDVN 375 : 2006 do Vin Khoa hc Cng ngh Xy dng bin son, V Khoa hc Cng ngh trnh duyt, B Xy dng ban hnh theo quyt nh s ngy thng nm 2006.

2

Tiu chun xy dng vit nam

TCXDVN 375 : 2006

Xut bn ln 1

Thit k cng trnh chu ng tDesign of structures for earthquake resistancesPhn 1: Quy nh chung, tc ng ng t v quy nh i vi kt cu nh 1. 1.1. 1.1.1. (1)P Tng qut Phm vi p dng Phm vi p dng ca tiu chun: Thit k cng trnh chu ng t Tiu chun ny p dng thit k nh v cng trnh xy dng trong vng c ng t. Mc ch ca tiu chun ny l bo m trong trng hp c ng t th: Sinh mng con ngi c bo v; Cc h hng c hn ch; Nhng cng trnh quan trng c chc nng bo v dn s vn c th duy tr hot ng.Ghi ch: Do bn cht ngu nhin ca hin tng ng t cng nh nhng hn ch ca cc gii php hin c nhm gii quyt hu qu ng t nn nhng mc ch ni trn ch l tng i kh thi v ch c th nh gi thng qua khi nim xc sut. Mc bo v i vi cc loi cng trnh khc nhau ch c th nh gi thng qua khi nim xc sut l mt bi ton phn b ti u cc ngun ti nguyn v do vy c th thay i tu theo tng quc gia, tu theo tm quan trng tng i ca nguy c ng t so vi cc nguy c do cc nguyn nhn khc cng nh tu theo iu kin kinh t ni chung.

(2)P

Nhng cng trnh c bit nh nh my in ht nhn, cng trnh ngoi khi v cc p ln nm ngoi phm vi quy nh ca tiu chun ny.

(3)P

Ngoi nhng iu khon ca cc tiu chun khc c lin quan, tiu chun thit k ny ch bao gm nhng iu khon buc phi tun theo khi thit k cng trnh trong vng ng t. Tiu chun ny b sung v kha cnh khng chn cho cc tiu chun khc.

1.1.2. (1)

Phm vi p dng ca Phn 1 Tiu chun ny p dng thit k nh v cng trnh xy dng trong vng c ng t. Tiu chun c chia thnh 10 chng, trong c mt s chng dnh ring cho thit k nh.

(2)

Chng 2 bao gm nhng yu cu v tnh nng v cc tiu ch cn tun theo p dng cho nh v cng trnh xy dng trong vng ng t.

(3)

Chng 3 bao gm nhng quy nh biu din tc ng ng t v vic t hp chng vi cc tc ng khc. 3

TCXDVN 375 : 2006

(4) (5)

Chng 4 bao gm nhng quy nh thit k chung, c bit lin quan n nh. Chng 5 ti chng 9 gm nhng quy nh thit k c th cho cc loi vt liu, cu kin v kt cu khc nhau, c bit lin quan n nh. Chng 5: Nhng quy nh c th cho kt cu btng; Chng 6: Nhng quy nh c th cho kt cu thp; Chng 7: Nhng quy nh c th cho kt cu lin hp thp - btng; Chng 8: Nhng quy nh c th cho kt cu g; Chng 9: Nhng quy nh c th cho kt cu xy;

(6)

Chng 10 bao gm nhng yu cu c bn v cc kha cnh cn thit khc ca vic thit k v an ton c lin quan ti cch chn y kt cu, c bit l cch chn y nh.

(7)

Ph lc C bao gm nhng quy nh b sung lin quan ti vic thit k ct thp bn cnh ca dm lin hp thp - btng v tr nt dm - ct ca khung chu mmen.Ghi ch: Ph lc tham kho A v ph lc tham kho B bao gm nhng qui nh b sung lin quan n ph phn ng chuyn v n hi v lin quan n chuyn v mc tiu trong phn tch phi tuyn tnh.

1.2. (1)P

Cc ti liu tham kho v tiu chun Tiu chun ny c hnh thnh t cc ti liu tham kho c hoc khng ngy thng v nhng iu khon t cc n phm khc. Cc ti liu tham kho c trch dn ti nhng v tr thch hp trong vn bn tiu chun v cc n phm c lit k di y. i vi cc ti liu c ngy thng, nhng sa i b sung sau ngy xut bn ch c p dng i vi tiu chun khi tiu chun ny c sa i, b sung. i vi cc ti liu khng ngy thng th dng phin bn mi nht.

1.2.1.

Cc tiu chun tham kho chung EN 1990 Eurocode 0 - C s thit k kt cu

EN 1992-1-1 Eurocode 2 - Thit k kt cu btng Phn 1-1: Tng qut - Nhng quy nh chung v nhng quy nh cho nh v cng trnh dn dng EN 1993-1-1 Eurocode 3 - Thit k kt cu thp - Phn 1-1: Tng qut - Nhng quy nh chung EN 1994-1-1 Eurocode 4 - Thit k kt cu lin hp thp - btng - Phn 1-1: Tng qut Nhng quy nh chung v nhng quy nh cho nh

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EN 1995-1-1 Eurocode 5 - Thit k kt cu g - Phn 1-1: Tng qut - Nhng quy nh chung v nhng quy nh cho nh EN 1996-1-1 Eurocode 6 - Thit k kt cu xy - Phn 1-1: Tng qut - Nhng quy nh cho kt cu xy c ct thp v khng c ct thp EN 1997-1-1 Eurocode 7 - Thit k a k thut - Phn 1: Nhng quy nh chung 1.2.2. (1)P (2) Nhng Quy chun v Tiu chun tham kho khc p dng tiu chun ny phi tham kho cc Tiu chun EN 1990, EN 1997 v EN 1999. Tiu chun ny cn bao gm cc ti liu tham kho khc v tiu chun c trch dn ti nhng ch ph hp trong vn bn tiu chun. Nhng ti liu tham kho v tiu chun y l: ISO 1000 EN 1090-1 n v o lng quc t (h SI) v ng dng ca n; Thi cng kt cu thp Phn 1: Nhng qui nh chung v nhng qui nh cho nh. 1.3. (1) Cc gi thit Gi thit chung: - La chn v thit k kt cu c thc hin bi nhng ngi c kinh nghim v c trnh thch hp; - Thi cng c tin hnh bi nhng ngi c kinh nghim v c k nng thch hp; - Gim st v kim tra cht lng c thc hin y trong qu trnh cng tc vn phng thit k, cng xng, nh my v ngoi hin trng; - Vt liu v sn phm xy dng c s dng theo quy nh ca cc tiu chun hin hnh c lin quan, theo ti liu tham kho hoc theo cc ch dn k thut sn phm; - Kt cu c bo tr y , ng cch; - Kt cu c s dng ph hp vi gi thit thit k. (2)P Gi thit l s khng xy ra nhng thay i trong kt cu giai on thi cng hoc giai on s dng sau ny ca cng trnh, tr nhng thay i c l do xc ng v c kim chng l ng n. Do bn cht c th ca phn ng ng t, iu ny c p dng ngay c cho trng hp c nhng thay i lm tng bn ca kt cu. 1.4. (1) S phn bit gia cc nguyn tc v cc quy nh p dng Cc nguyn tc bao gm: 5

TCXDVN 375 : 2006

- Cc ch dn v nh ngha chung khng c la chn no khc; - Cc yu cu v m hnh phn tch khng c la chn no khc tr phi c nhng ch dn ring. (2) (3) Cc nguyn tc c k hiu bng ch P sau con s nm trong ngoc n, v d (1)P. Cc quy nh p dng ni chung l nhng quy nh c xy dng trn c s tha nhn cc nguyn tc v tho mn cc yu cu ca n. (4) Cho php s dng cc quy nh thit k la chn khc vi cc quy nh p dng, vi iu kin cc quy nh la chn phi ph hp vi nhng nguyn tc c lin quan v t nht chng phi tng ng v mt an ton, kh nng s dng v bn ca kt cu. (5) 1.5. 1.5.1. (1) 1.5.2. (1) Cc quy nh p dng c k hiu bng mt con s nm trong ngoc n, v d (1). Thut ng v nh ngha Thut ng chung Nhng thut ng v nh ngha c cho trong Ph lc D; Cc thut ng khc c s dng trong tiu chun Di y nh ngha mt s thut ng c s dng trong tiu chun ny: H s ng x H s c s dng cho mc ch thit k gim ln ca lc thu c t phn tch tuyn tnh, nhm xt n phn ng phi tuyn ca kt cu, lin quan n vt liu, h kt cu v quy trnh thit k. Phng php thit k theo kh nng chu lc v tiu tn nng lng Phng php thit k trong mt s cu kin ca h kt cu c la chn, thit k v cu to ph hp nhm m bo tiu tn nng lng thng qua cc bin dng ln trong khi tt c nhng cu kin cn li vn m bo bn c th duy tr c cch tiu tn nng lng chn. Kt cu tiu tn nng lng Kt cu c kh nng tiu tn nng lng bng cch ng x tr do do kt cu v/hoc bng cc c ch khc. Vng tiu tn nng lng

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Vng c nh trc ca mt kt cu tiu tn nng lng. S tiu tn nng lng ca kt cu ch yu tp trung ti y.Ghi ch 1: Vng ny cn c gi l vng ti hn.

n v c lp v mt ng lc Kt cu hoc mt phn kt cu trc tip chu dao ng nn v phn ng ca n khng chu nh hng bi phn ng ca cc n v hoc kt cu bn cnh. H s tm quan trng H s c lin quan n nhng hu qu ca vic h hng kt cu. Kt cu khng tiu tn nng lng Kt cu c thit k cho trng hp chu ng t nhng khng tnh n ng x phi tuyn ca vt liu. B phn phi kt cu Cc b phn kin trc, c kh hoc in, do khng c kh nng chu lc hoc do cch lin kt vi kt cu khng c xem l cu kin chu lc trong thit k chu ng t. Cu kin khng chn chnh Cu kin c xem l mt phn ca h kt cu chu tc ng ng t, c m hnh ha trong tnh ton thit k chu ng t v c thit k, cu to hon chnh m bo yu cu khng chn theo nhng quy nh ca tiu chun ny. Cu kin khng chn ph

Cu kin khng c xem l mt phn ca h kt cu chu tc ng ng t. Cng v cng chng li tc ng ng t ca n c b qua.Ghi ch 2: Nhng cu kin ny khng yu cu phi tun th tt c cc quy nh ca tiu chun ny, nhng phi c thit k v cu to sao cho vn c th chu c trng lc khi chu cc chuyn v gy ra bi tnh hung thit k chu ng t.

Phn cng pha di Phn nh v cng trnh c xem l cng tuyt i so vi phn nh v cng trnh pha trn n, v d ct ng ten v tuyn t trn mi nh, phn nh t mi tr xung c xem l phn cng pha di ca ct ng ten. Hiu ng bc 2 (hiu ng P-)

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Mt cch tnh kt cu theo s tnh bin dng. 1.6. 1.6.1. (1) K hiu Tng qut p dng nhng k hiu cho trong Ph lc E. Vi nhng k hiu lin quan n vt liu, cng nh nhng k hiu khng lin quan mt cch c th vi ng t th p dng nhng iu khon ca cc tiu chun lin quan khc. (2) Nhng k hiu khc, lin quan n tc ng ng t, c nh ngha trong vn bn tiu chun ni chng xut hin d s dng. Tuy nhin, cc k hiu xut hin thng xuyn nht c s dng trong tiu chun ny c lit k v nh ngha trong 1.6.2 ti 1.6.3. 1.6.2. Cc k hiu khc c s dng trong chng 2 v chng 3 AEd AEk Ed NSPT PNCR Gi tr thit k ca tc ng ng t ( = I . AEk) Gi tr c trng ca tc ng ng t i vi chu k lp tham chiu Gi tr thit k ca cc h qu tc ng S nht p trong th nghim xuyn tiu chun (SPT) Xc sut tham chiu vt qu trong 50 nm ca tc ng ng t tham chiu i vi yu cu khng sp Q S Se(T) Tc ng thay i H s t nn Ph phn ng gia tc nn n hi theo phng nm ngang cn gi l ph phn ng n hi. Khi T= 0, gia tc ph cho bi ph ny bng gia tc nn thit k cho nn loi A nhn vi h s t nn S. Sve(T) SDe(T) Sd(T) Ph phn ng gia tc nn n hi theo phng thng ng Ph phn ng chuyn v n hi Ph thit k (trong phn tch n hi). Khi T= 0, gia tc ph cho bi ph ny bng gia tc nn thit k trn nn loi A nhn vi h s t nn S T Ts Chu k dao ng ca h tuyn tnh mt bc t do Khong thi gian ko di dao ng trong bin khng nh hn 1/3 bin cc i. TNCR Chu k lp tham chiu ca tc ng ng t tham chiu theo yu cu khng sp agR ag 8 nh gia tc nn tham chiu trn nn loi A Gia tc nn thit k trn nn loi A

TCXDVN 375 : 2006

avg cu dg g q vs,30

Gia tc nn thit k theo phng thng ng Cng chng ct khng thot nc ca t nn Chuyn v nn thit k Gia tc trng trng H s ng x Gi tr trung bnh ca vn tc truyn sng ct trong 30m pha trn ca mt ct t nn ni c bin dng ct bng hoc thp hn10-5.

I 2,i E,i1.6.3.

H s tm quan trng H s hiu chnh cn T s cn nht tnh bng phn trm H s t hp cho gi tr c coi l lu di ca tc ng thay i i H s t hp cho tc ng thay i i, s dng khi xc nh cc h qu ca tc ng ng t thit k

Cc k hiu khc c s dng trong chng 4 EE EEdx, EEdy H qu ca tc ng ng t Gi tr thit k ca cc h qu tc ng gy ra bi cc thnh phn nm ngang (x v y) ca tc ng ng t EEdz Gi tr thit k ca cc h qu tc ng gy ra bi thnh phn thng ng ca tc ng ng t

Fi Fa Fb H Lmax, Lmin

T s gia gia tc nn thit k v gia tc trng trng Lc ng t theo phng nm ngang ti tng th i Lc ng t theo phng nm ngang tc ng ln mt b phn phi kt cu Lc ct y Chiu cao nh k t mng hoc t nh ca phn cng pha di Kch thc ln nht v kch thc nh nht trn mt bng ca ngi nh o theo cc phng vung gc

Rd Sa T1 Ta Wa

Gi tr thit k ca bn H s ng t ca b phn phi kt cu Chu k dao ng c bn ca cng trnh Chu k dao ng c bn ca b phn phi kt cu Trng lng ca b phn phi kt cu 9

TCXDVN 375 : 2006

d dr ea h mi n qa qd si zi

Chuyn v Chuyn v ngang thit k tng i gia cc tng lch tm ngu nhin ca khi lng mt tng so vi v tr danh ngha ca n Chiu cao tng Khi lng tng th i S tng pha trn mng hoc trn nh ca phn cng pha di H s ng x ca b phn phi kt cu. H s ng x chuyn v Chuyn v ca khi lng mi trong dng dao ng c bn ca cng trnh Chiu cao ca khi lng mi pha trn cao trnh t tc ng ng t H s tm quan trng ca b phn phi kt cu H s vt cng cho tm cng (i-a-phc) H s nhy ca chuyn v ngang tng i gia cc tng.

a d 1.6.4.

Cc k hiu khc c s dng trong chng 5

Ac Ash Asi Ast Asv Asv,i Aw Asi Asj

Din tch tit din ca cu kin btng Tng din tch tit din ca ct thp ai nm ngang trong nt dm-ct Tng din tch cc thanh ct thp theo tng phng cho ca dm lin kt Din tch tit din ca ct thp ngang Tng din tch ct thp ng bng tng Tng din tch ca cc thanh thp ng ca ct nm gia cc thanh gc theo mt phng i qua nt Tng din tch tit din chiu ln mt nm ngang ca tng Tng din tch ca tt c cc thanh thp xin theo c hai phng, khi trong tng c b tr cc thanh thp xin chng li s ct do trt Tng din tch ca tt c cc thanh thp thng ng trong phn bng tng, hoc ca cc thanh thp b sung c b tr theo mt cch ring phn u tng chng li s ct do trt

MRb MRc

Tng cc gi tr thit k ca kh nng chu mmen un ca cc dm quy t vo nt ti mi ni theo phng ang xt Tng cc gi tr thit k ca kh nng chu mmen un ca cc ct hnh thnh nn khung ti mt mi ni theo phng ang xt

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Do Mi,d MRb,i MRc,i NEd T1 TC V Vdd VEd VEd,max VEd,min Vfd Vid VRd, c VRd, S b bc beff bi b0 bwEd

ng knh ca li c ct ai hn ch bin dng trong ct tit din trn Mmen ti u mt ca mt dm hoc ct tnh tan kh nng chu ct thit k Gi tr thit k kh nng chu mmen un ca dm ti u mt th i Gi tr thit k ca kh nng chu mmen un ca ct ti u mt th i Lc dc trc thu c t php phn tch theo tnh hung thit k chu ng t Chu k c bn ca cng trnh theo phng ang xt Chu k ng vi gii hn trn ca on c gia tc khng i ca ph n hi Lc ct trong tng thu c t php phn tch theo tnh hung thit k chu ng t Kh nng cht ca cc thanh thp thng ng trong tng Lc ct thit k trong tng Lc ct tc dng ln nht ti tit din u mt ca dm thu c t tnh ton thit k theo kh nng chu lc Lc ct tc dng nh nht ti tit din u mt ca dm thu c t tnh ton thit k theo kh nng chu lc Phn lc ma st tham gia lm tng kh nng ca tng chng li s ct do trt Phn lc ng gp do cc thanh thp xin vo bn ca tng chng li s ct do trt Gi tr thit k ca kh nng chu ct ca cc cu kin khng c ct thp chu ct theo tiu chun EN 1992-1-1:2004 Gi tr thit k ca kh nng chu ct chng li s trt Chiu rng cnh di ca dm Kch thc tit din ngang ca ct Chiu rng hu hiu ca cnh dm chu ko ti b mt ca ct Khong cch gia cc thanh lin k nhau c gii hn bi gc un ca ct thp ai hoc bi ai mc trong ct Chiu rng ca phn li c ct ai hn ch bin dng trong ct hoc trong phn u tng ca tng (tnh ti ng tm ca ct thp ai) B dy ca phn c ct ai hn ch bin dng ca tit din tng, hoc chiu rng bng dm

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bw0 d dbL dbw fcd fctm fyd fyd, h fyd, v fyld fywd h hc hf hjc hjw h0 hs hw kD

B dy phn bng tng Chiu cao lm vic ca tit din ng knh thanh ct thp dc ng knh thanh ct thp ai Gi tr thit k ca cng chu nn ca btng Gi tr trung bnh ca cng chu ko ca btng Gi tr thit k ca gii hn chy ca thp Gi tr thit k ca gii hn chy ca ct thp ca bng dm theo phng nm ngang Gi tr thit k ca gii hn chy ca ct thp ca bng dm theo phng ng Gi tr thit k ca gii hn chy ca ct thp dc Gi tr thit k ca gii hn chy ca ct thp ngang Chiu cao tit din ngang Chiu cao tit din ngang ca ct theo phng ang xt B dy cnh Khong cch gia cc lp ngoi cng ca ct thp ct trong nt dm-ct Khong cch gia cc thanh ct thp pha trn v pha di dm Chiu cao phn li c ct ai hn ch bin dng trong mt ct (tnh ti ng tm ca ct thp ai) Chiu cao thng thy ca tng Chiu cao tng hoc chiu cao tit din ngang ca dm H s phn nh cp do kt cu trong tnh ton chiu cao tit din ct cn thit neo cc thanh thp dm trong nt, ly bng 1 cho cp do kt cu cao v bng 2/3 cho cp do kt cu trung bnh

kw lc1 lcr li lw12

H s phn nh dng ph hoi ch o trong h kt cu c tng chu lc Chiu di thng thy ca dm hoc ct Chiu di vng ti hn Khong cch gia cc ng tm ca hai hng ct thp xin ti tit din chn tng c cc thanh ct thp xin chu ct do trt Chiu di tit din ngang ca tng

TCXDVN 375 : 2006

n q0 s xu z

Tng s cc thanh thp dc c gi bi cc thanh ct thp ai hoc ging ngang theo chu vi ca tit din ct Gi tr c bn ca h s ng x Khong cch ct thp ngang Chiu cao ca trc trung ha Cnh tay n ca ni lc H s hiu ng hn ch bin dng, gc gia cc thanh thp t cho v trc ca dm lin kt

0 1 u c Rd s cu2 cu2,c su,k sy,d f v

T s kch thc ca tng trong h kt cu H s nhn ca tc ng ng t thit k theo phng nm ngang ti thi im hnh thnh khp do u tin trong h kt cu H s nhn ca tc ng ng t thit k theo phng nm ngang ti thi im hnh thnh c ch do ton b H s ring ca btng H s thiu tin cy ca m hnh i vi gi tr thit k ca bn khi tnh h qu ca tc ng, c tnh n cc nguyn nhn vt cng khc nhau H s ring ca thp Bin dng ti hn ca btng khng c ct ai hn ch bin dng Bin dng ti hn ca btng c ct ai hn ch bin dng Gi tr c trng ca dn di gii hn ca ct thp Gi tr thit k ca bin dng thp ti im chy do H s gim cng chu nn ca btng do bin dng ko theo phng ngang ca tit din T s VEd,min/VEd,max gia cc lc ct tc dng nh nht v ln nht ti tit din u mt ca dm H s ma st gia btng vi btng khi chu tc ng c chu k H s do kt cu khi un H s do kt cu khi chuyn v Lc dc quy i trong tnh hung thit k chu ng t Chiu cao quy i tnh n trc trung ha

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cm h 1 max v w v wd

Hm lng ct thp chu ko Hm lng ct thp chu nn trong dm Gi tr trung bnh ca ng sut php ca btng Hm lng ct thp ca cc thanh nm ngang ca phn bng tng Tng hm lng ct thp dc Hm lng ct thp chu ko cho php ti a trong vng ti hn ca dm khng chn chnh Hm lng ct thp ca cc thanh thng ng ca phn bng tng Hm lng ct thp chu ct T s c hc ca ct thp thng ng trong bn bng T s th tch c hc ca ct ai hn ch bin dng trong pham vi cc vng ti hn

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1.6.5.

Cc k hiu khc c s dng trong chng 6

L MEd Mp1,RdA Mp1,RdB NEd NEd,E NEd,G Np1,Rd NRd (MEd,VEd) Rd Rfy VEd VEd,G VEd,M Vwp,Ed Vwp,Rd e fy fymax q tw tf

Nhp dm Mmen un thit k tnh ton theo tnh hung thit k chu ng t Gi tr thit k ca mmen do ti u mt A ca mt cu kin Gi tr thit k ca mmen do ti u mt B ca mt cu kin Lc dc thit k tnh ton theo tnh hung thit k chu ng t Lc dc t php tnh ton ch do tc ng ng t thit k Lc dc do cc tc ng khng phi tc ng ng t, c k n trong t hp cc tc ng theo tnh hung thit k chu ng t Gi tr thit k ca bn do khi ko ca tit din ngang ca mt cu kin theo EN 1993-1-1:2004 Gi tr thit k ca lc dc trong ct hoc thanh cho theo EN 1993-1-1:2004, c tnh n s tng tc vi mmen un Med v lc ct VEd trong tnh hung c ng t bn ca lin kt theo EN 1993-1-1:2004 bn do ca cu kin tiu tn nng lng c lin kt da trn ng sut chy thit k ca vt liu nh nh ngha trong EN 1993-1-1:2004 Lc ct thit k tnh ton theo tnh hung thit k chu ng t Lc ct do cc tc ng khng phi tc ng ng t c k n trong t hp tc ng theo tnh hung thit k chu ng t Lc ct do cc mmen do t vo ti hai u dm Lc ct thit k trong mt ca bn bng panen do tc ng ng t thit k gy ra bn ct thit k ca bn bng panen theo EN 1993-1-1:2004 Chiu di ca on ni khng chn Gii hn chy danh ngha ca thp ng sut chy cho php ti a ca thp H s ng x B dy bn bng ca on ni khng chn B dy bn cnh ca on ni khng chn

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H s nhn vi lc dc NEd,E. Lc dc ny c tnh t tc ng ng t thit k, dnh cho vic thit k cc cu kin khng tiu tn nng lng trong cc khung ging ng tm hoc lch tm tng ng vi iu (1) trong C1.6.7.4 v 6.8.3.

T s gia mmen un thit k nh hn MEd,A ti mt u mt ca on ni khng chn vi mmen un ln hn MEd,B ti u mt hnh thnh khp do, c hai mmen u c ly gi tr tuyt i

1 u M ov pb

H s nhn ca tc ng ng t thit k theo phng nm ngang ti thi im hnh thnh khp do u tin trong h kt cu H s nhn ca tc ng ng t thit k theo phng nm ngang ti thi im hnh thnh khp do trn ton b h kt cu H s ring cho tham s vt liu H s vt cng ca vt liu vng ca dm ti gia nhp so vi ng tip tuyn vi trc dm ti u dm (Hnh 6.11) H s nhn vi bn do thit k khi ko Np1,Rd ca ging chu nn trong h ging ch V, d tnh nh hng ca tc ng ng t khng cn bng ln dm m ging c lin kt vo

s p 1.6.6.

H s ring ca thp Kh nng xoay ca vng khp do mnh khng th nguyn ca mt cu kin nh nh ngha trong EN 19931-1:2004

Cc k hiu khc c s dng trong chng 7

Apl Ea Ecm Ia Ic Ieq Is

Din tch ca tm theo phng nm ngang Mun n hi ca thp Mun n hi trung bnh ca btng theo EN 1992-1-1:2004 Mmen qun tnh ca din tch phn thp trong tit din lin hp, i vi trc i qua tm ca tit din lin hp Mmen qun tnh ca din tch phn btng trong tit din lin hp, i vi trc i qua tm ca tit din lin hp Mmen qun tnh tng ng ca din tch tit din lin hp Mmen qun tnh ca din tch cc thanh ct thp trong mt tit din lin hp, i vi trc i qua tm ca tit din lin hp

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Mp1,Rd,c

Mmen do ca ct, c ly l cn di v c tnh ton c xt ti phn btng ca tit din v ch xt ti phn thp ca tit din c xp vo loi c tnh do kt cu

MU,Rd,b

Cn trn ca mmen do ca dm, c tnh ton c xt ti phn btng ca tit din v ton b phn thp trong tit din , k c nhng tit din khng c coi l c tnh do kt cu

Vwp,Ed Vwp,Rd b be beff b0 dbL dbw fyd fydf fydw hb bb hc kr kt lcl lcr n q r tf

Lc ct thit k trong bn bng, c tnh ton trn c s bn do ca cc vng tiu tn nng lng lin k trong dm hoc trong cc mi lin kt bn ct ca bn bng bng lin hp thp - btng theo EN 1994-1:2004 Chiu rng ca bn cnh Chiu rng tnh ton bn cnh v mi pha ca bn bng bng thp Tng chiu rng hu hiu ca bn cnh bng btng Chiu rng (kch thc nh nht) ca li btng b hn ch bin dng ng knh ct thp dc ng knh ct thp ai Gii hn chy thit k ca thp Gii hn chy thit k ca thp trong bn cnh Cng thit k ca ct thp bn bng Chiu cao ca dm lin hp Chiu rng ca dm lin hp Chiu cao ca tit din ct lin hp thp - btng H s hu hiu ca hnh dng cc sn ca mt ct tm thp H s suy gim bn ct thit k ca cc nt lin kt theo EN 1994-1 Chiu di thng thy ca ct Chiu di ca vng ti hn T s mun thp - btng i vi tc ng ngn hn H s ng x H s gim cng btng tnh ton cng ca ct lin hp thp - btng B dy bn cnh

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c M ov s a cu2 1.6.7.

H s ring ca btng H s ring cho tham s vt liu H s vt cng ca vt liu H s ring ca thp Tng bin dng ca thp ti trng thi cc hn Bin dng nn cc hn ca btng khng b hn ch bin dng lin kt ti thiu nh nh ngha trong 6.6.1.2 ca EN 1994-1-1:2004

Cc k hiu khc c s dng trong chng 8

E0 b d h kmod q M1.6.8.

Mun n hi ca g khi cht ti tc thi Chiu rng ca tit din g ng knh vt lin kt Chiu cao ca dm g H s iu chnh cng ca g cho cht ti tc thi theo EN 1995-1-1:2004 H s ng x H s ring cho tham s vt liu

Cc k hiu khc c s dng trong chng 9

ag,urm Amin fb, min fbh, min fm, min h hef l n18

Gi tr cn trn ca gia tc nn thit k s dng cho loi khi xy khng c ct thp tha mn nhng iu khon ca tiu chun ny Tng din tch tit din ngang ca tng xy yu cu trong mi hng nm ngang p dng cc quy nh cho nh xy n gin Cng nn tiu chun ca vin xy vung gc vi mt y Cng nn tiu chun ca vin xy song song vi mt y v trong mt phng tng Cng ti thiu cho va xy Chiu cao thng thy ln nht ca l m lin k vi bc tng Chiu cao hu hiu ca tng Chiu di ca tng S tng nm pha trn mt t

TCXDVN 375 : 2006

pA,min pmax q tef A,max m,max M s min1.6.9.

T l phn trm ti thiu ca tng din tch tit din chiu ln mt ngang ca vch cng theo tng phng vi tng din tch ngang theo tng T l phn trm ca tng din tch sn bn trn mc ang xt H s ng x B dy hu hiu ca tng chnh lch ln nht v din tch tit din ngang ca vch cng ngang gia cc tng lin k nhau ca nh xy n gin chnh lch ln nht v khi lng gia cc tng lin k nhau ca nh xy n gin H s ring cho tham s vt liu H s ring ca ct thp T s gia kch thc ca cnh ngn v cnh di trong mt bng

Cc k hiu khc c s dng trong chng 10

Keff KV Kxi Kyi Teff Tf TV M Ms ddc ddb etot,y fj ry

cng hu hiu ca h cch chn theo phng nm ngang xem xt, ti mt chuyn v tng ng vi chuyn v thit k ddc cng tng cng ca h cch chn theo phng thng ng cng hu hiu ca b cch chn th i theo phng x cng hu hiu ca b cch chn th i theo phng y Chu k c bn hu hiu ca kt cu bn trn trong chuyn ng tnh tin ngang, kt cu bn trn c xem l tuyt i cng Chu k c bn ca kt cu bn trn c gi thit l ngm ti y Chu k c bn ca kt cu bn trn theo phng thng ng, kt cu bn trn c xem l tuyt i cng Khi lng ca kt cu bn trn mnh Chuyn v thit k hu hiu ca tm cng theo phng xem xt Tng chuyn v thit k ca b cch chn Tng lch tm theo phng y Lc theo phng ngang ti mi tng th j Bn knh xon ca h cch chn 19

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(xi,yi)

Ta ca b cch chn th i so vi tm cng hu hiu H s khuch i cn hu hiu

ieff1.7. (1)P (2) n v SI

Cc n v SI phi c s dng ph hp vi ISO 1000. Khi tnh ton dng cc n v sau y: - Lc v ti trng: - Khi lng ring: - Khi lng: - Trng lng ring: - ng sut v cng : - Mmen (un,v.v..): - Gia tc: kN, kN/m, kN/m2 kg/m3, t/m3 kg, t kN/m3 N/mm2 (= MN/m2 hoc MPa), kN/m2 (=kPa) kNm m/s2, g (g=9,81m/s2)

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2. 2.1. (1)P

Yu cu v tnh nng v cc tiu ch cn tun theo Nhng yu cu c bn Kt cu trong vng c ng t phi c thit k v thi cng sao cho tho mn nhng yu cu sau y. Mi yu cu phi c tin cy thch hp: Yu cu khng sp :

Kt cu phi c thit k v thi cng chu c tc ng ng t thit k nh nh ngha trong Chng 3 m khng b sp cc b hay sp ton phn, ng thi gi c tnh ton vn ca kt cu v cn mt phn kh nng chu ti trng sau khi ng t xy ra. Tc ng ng t thit k c biu th qua cc yu t: a) tc ng ng t tham chiu gn lin vi xc sut vt qu tham chiu PNCR, trong 50 nm hoc mt chu k lp tham chiu, TNCR, b) h s tm quan trng I (xem (2)P v (3)P ca iu ny) tnh n mc tin cy khc nhau.Ghi ch 1: Cc gi tr n nh cho P NCR hoc cho T NCR s dng cho Vit Nam l P NCR =10% vT NCR = 475 nm. Ghi ch 2: Gi tr ca xc sut vt qu PR, trong TL nm ca mc tc ng ng t c th c lin quan ti chu k lp trung bnh TR, ca mc tc ng ng t ny nh sau TR = TL ln (1- PR). V th, vi mt gi tr TL cho trc, tc ng ng t c th c xc nh mt cch tng ng theo 2 cch: hoc l bng chu k lp trung bnh, TR, hoc l bng xc sut vt qu, PR trong TL nm. Yu cu hn ch h hng:

Cng trnh phi c thit k v thi cng chu c tc ng ng t c xc sut xy ra ln hn so vi tc ng ng t thit k, m khng gy h hi v nhng hn ch s dng km theo v nhng chi ph khc phc c th ln hn mt cch bt hp l so vi gi thnh bn thn kt cu. Tc ng ng t c a vo tnh ton cho yu cu hn ch h hng c xc sut vt qu, PDLR trong 10 nm v chu k lp TDLR. Khi khng c nhng thng tin chnh xc hn, c th s dng h s gim tc ng ng t thit k theo 4.4.3.2(2) tnh tc ng ng t dng kim tra yu cu hn ch h hng.Ghi ch 3: Cc gi tr n nh cho PDLR hoc TDLR s dng Vit Nam l PDLR =10% v TDLR = 95 nm.

(2)P

tin cy cho yu cu khng sp v yu cu hn ch h hng c thit lp bi cc c quan nh nc c thm quyn i vi cc loi nh v cng trnh dn dng khc nhau trn c s nhng hu qu ca ph hoi.

(3)P

Cc mc tin cy khc nhau c xt ti bng cch phn loi cng trnh theo mc quan trng khc nhau. Mi mc quan trng c gn mt h s tm quan trng I. Khi c th c, h s ny cn thit lp sao cho n tng ng vi mt chu k lp c gi tr di hn hoc 21

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ngn hn ca hin tng ng t (so vi chu k lp tham chiu), cho chu k lp ny l ph hp thit k tng loi cng trnh c th (xem 3.2.1(3)). Cc nh ngha v mc v h s tm quan trng cho trong Ph lc F, Phn 1. (4) Cc mc khc nhau ca tin cy thu c bng cch nhn tc ng ng t tham chiu hoc nhn nhng h qu tc ng tng ng khi s dng phng php phn tch tuyn tnh vi h s tm quan trng ny. Ch dn chi tit v mc quan trng v cc h s tm quan trng c cho 4.2.5.Ghi ch: Ti hu ht cc a im, xc sut vt qu theo nm H(agR) ca nh gia tc nn tham chiu agR c th xem nh i lng bin thin theo agR nh sau: H(agR) k0 agR-k, vi gi tr ca s m k ph thuc vo tnh ng t, nhng ni chung l bng 3. V th, nu tc ng ng t c nh ngha di dng nh gia tc nn tham chiu agR, th gi tr ca h s tm quan trng I, m nhn vi tc ng ng t tham chiu t c cng mt xc sut vt qu trong TL nm cng nh trong TLR nm theo tc ng ng t tham chiu c xc nh, c th c tnh bng: I (TLR/ TL)-1/k. Mt cch khc, gi tr ca h s tm quan trng I, m phi nhn vi tc ng ng t tham chiu t c xc sut vt qu PL ca tc ng ng t trong TL nm, khc vi xc sut vt qu tham chiu PLR, cng trn cng s nm l TL, c th c tnh bng: I (PL/ PLR)-1/k.

2.2. 2.2.1. (1)P

Cc tiu ch cn tun theo Tng qut tha mn nhng yu cu c bn a ra trong 2.1, cc trng thi gii hn sau y phi c kim tra (xem 2.2.2 v 2.2.3): Cc trng thi cc hn Cc trng thi hn ch h hng

Cc trng thi cc hn l cc trng thi lin quan ti s sp hoc cc dng h hng khc ca kt cu c th gy nguy him cho s an ton ca con ngi. Cc trng thi hn ch h hng l cc trng thi lin quan ti s h hng m vt qu s lm cho mt s yu cu s dng c th khng cn c tho mn. (2)P hn ch nguy c v nng cao kh nng lm vic tt ca kt cu khi chu nhng tc ng ng t nghim trng hn so vi tc ng ng t thit k, phi thc hin thm mt lot bin php c th thch hp (xem 2.2.4). (3) i vi cc loi kt cu xc nh r l xy dng trong vng ng t yu (xem 3.2.1(4)), nhng yu cu c bn c th tho mn thng qua vic p dng nhng quy nh n gin hn so vi nhng quy nh cho trong cc phn c lin quan ca tiu chun ny.

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(4)

Trong trng hp ng t rt yu, khng nht thit phi tun theo nhng iu khon ca tiu chun ny (xem 3.2.1(5) v ghi ch v nh ngha nhng trng hp ng t rt yu).

(5)

Nhng quy nh c th cho Nh xy n gin c cho trong chng 9. Khi tun th nhng quy nh ny, Nh xy n gin nh vy c xem l tho mn cc yu cu c bn ca tiu chun ny m khng cn kim tra phn tch an ton.

2.2.2. (1)P

Trng thi cc hn H kt cu phi c kim tra v kh nng chu lc v kh nng tiu tn nng lng nh quy nh trong cc phn c lin quan ca tiu chun ny.

(2)

Kh nng chu lc v kh nng tiu tn nng lng ca kt cu lin quan n kh nng khai thc phn ng phi tuyn ca n. Trong thc t, s cn bng gia kh nng chu lc v kh nng tiu tn nng lng c c trng bi cc gi tr ca h s ng x q v vic phn cp do tng ng, cho trong cc phn c lin quan ca tiu chun ny. Trong trng hp gii hn, khi thit k cc kt cu c xem l khng tiu tn nng lng th khng tnh n bt k mt s tiu tn nng lng no do hin tng tr v ni chung khng xt ti h s ng x q ln hn 1,5, l gi tr tnh n kh nng vt cng . i vi kt cu thp hoc kt cu lin hp thp btng, gi tr gii hn ny ca h s q c th ly t 1,5 n 2. Vi nhng kt cu tiu tn nng lng, tnh n s tiu tn nng lng tr, h s ng x c ly ln hn nhng gi tr gii hn ni trn. S tiu tn nng lng ny ch yu xy ra trong cc vng c thit k mt cch c bit, gi l vng tiu tn nng lng hoc vng ti hn.Ghi ch: Gi tr ca h s ng x q cn c gii hn bi trng thi gii hn n nh ng ca kt cu v bi s h hng do mi chu k thp ca cc chi tit kt cu (c bit l cc lin kt). Phi p dng iu kin gii hn bt li nht khi xc nh cc gi tr ca h s q. Cc gi tr ca h s q cho trong cc chng lin quan c xem l tun th yu cu ny.

(3)P

Phi kim tra bo m n nh ca kt cu tng th di tc ng ng t thit k. Cn phi xem xt c n nh v trt ln v lt. Nhng quy nh c th kim tra v lt ca cng trnh c cho trong cc phn lin quan ca tiu chun ny.

(4)P

Phi kim tra c cu kin mng v t di mng c kh nng chu c nhng h qu ca tc ng sinh ra t phn ng ca kt cu bn trn m khng gy ra nhng bin dng thng xuyn ng k. Trong vic xc nh cc phn lc, phi xt n bn thc t ca cu kin kt cu truyn ti.

(5)P

Khi phn tch cn xt nh hng c th c ca cc hiu ng bc hai n cc gi tr ca cc h qu tc ng.

(6)P

Phi kim tra di tc ng ng t thit k, ng x ca cc b phn phi kt cu khng gy ri ro cho con ngi v khng gy nh hng bt li ti phn ng ca cc cu kin chu lc. i vi nh, nhng quy nh c th c cho 4.3.5 v 4.3.6.

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2.2.3. (1)P

Trng thi hn ch h hng Cn bo m ngn chn cc h hng khng th chp nhn vi tin cy ph hp bng cch tho mn nhng gii hn v bin dng hoc cc gii hn khc c nh ngha trong cc phn c lin quan ca tiu chun ny.

(2)P

Trong nhng cng trnh quan trng c chc nng bo v dn s, h kt cu phi c kim tra bo m rng chng c cng v bn nhm duy tr s hot ng ca cc thit b phc v thit yu khi xy ra ng t vi mt chu k lp ph hp.

2.2.4.

Cc bin php c th

2.2.4.1. Thit k (1) mc c th, kt cu cn c hnh dng n gin v cn i trong c mt bng ln mt ng, (xem 4.2.3). Nu cn thit, c th chia kt cu thnh cc n nguyn c lp v mt ng lc bng cc khe khng chn. (2)P bo m ng x do v tiu tn nng lng tng th, phi trnh s ph hoi gin hoc s hnh thnh sm c cu mt n nh. t c mc ch , theo yu cu trong cc phn c lin quan ca tiu chun ny, phi s dng quy trnh thit k theo kh nng chu lc v tiu tn nng lng. Quy trnh ny c s dng c c cc thnh phn kt cu khc nhau xp theo cp bc bn v theo cc dng ph hoi cn thit bo m mt c cu do ph hp v trnh cc dng ph hoi gin. (3)P Do tnh nng khng chn ca kt cu ph thuc rt nhiu vo ng x ca cc vng hoc cu kin ti hn ca n, cu to kt cu ni chung v cc vng hoc cc cu kin ti hn ni ring phi duy tr c kh nng truyn lc v tiu tn nng lng cn thit trong iu kin tc ng c chu k. p ng yu cu ny, trong thit k cn quan tm c bit n cc chi tit cu to lin kt gia cc cu kin chu lc v chi tit cu to cc vng d on c ng x phi tuyn. (4)P Phng php phn tch phi da vo m hnh kt cu ph hp, khi cn thit, m hnh ny phi xt ti nh hng ca bin dng nn t, ca nhng b phn phi kt cu v nhng kha cnh khc, chng hn nh s hin din ca nhng kt cu lin k. 2.2.4.2. H mng (1)P cng ca h mng phi truyn nhng tc ng nhn c t kt cu bn trn xung nn t cng u n cng tt. (2) Tr cng trnh cu, ni chung ch nn s dng mt dng mng cho cng mt cng trnh, tr phi cng trnh gm cc n nguyn c lp v mt ng lc.

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2.2.4.3. K hoch m bo cht lng (1)P H s thit k phi ch r kch thc, chi tit cu to v tham s vt liu ca cc cu kin. Nu c th, h s thit k cn phi bao gm c nhng c trng ca cc thit b c bit s s dng, khong cch gia nhng cu kin chu lc v b phn phi kt cu. Nhng iu khon kim sot cht lng cn thit cng phi c nu ra trong h s thit k. (2)P Yu cu phi c s kim tra c bit trong qu trnh thi cng cc cu kin c tm quan trng c bit v mt kt cu v phi c ch r trn cc bn v thit k. Trong trng hp ny, cng phi quy nh cc phng php kim tra s c s dng. (3) Trong vng ng t mnh v i vi cc cng trnh c tm quan trng c bit, cn lp k hoch chnh thc m bo cht lng, bao gm cc khu thit k, thi cng v s dng cng trnh. K hoch m bo cht lng ny l b sung vo quy trnh kim sot cht lng trong cc tiu chun khc c lin quan. 3. 3.1. 3.1.1. (1)P (2) iu kin nn t v tc ng ng t iu kin nn t Tng qut Phi thc hin cng tc kho st ph hp phn bit iu kin nn t theo 3.1.2. Nhng ch dn thm lin quan n kho st v phn loi nn t c cho trong 4.2, Phn 2. (3) a im xy dng v nn t chu lc ni chung cn trnh nhng ri ro t gy, mt n nh mi dc v ln gy nn bi s ho lng hoc s nn cht khi ng t xy ra. Kh nng xut hin cc hin tng nh th phi c kho st theo chng 4, Phn 2. (4) Cng tc kho st nn t v/hoc nghin cu a cht cn c thc hin xc nh tc ng ca ng t, ph thuc vo mc quan trng ca cng trnh v nhng iu kin c th ca d n. 3.1.2. (1) Nhn dng cc loi nn t Cc loi nn t A, B, C, D, v E c m t bng cc mt ct a tng, cc tham s cho trong Bng 3.1 v c m t di y, c th c s dng k n nh hng ca iu kin nn t ti tc ng ng t. Vic k n nh hng ny cn c th thc hin bng cch xem xt thm nh hng ca a cht tng su ti tc ng ng t. Bng 3.1. Cc loi nn t Loi M t Cc tham s

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vs,30(m/s) A hoc cc kin to a cht khc ta , k c cc t yu hn trn b mt vi b dy ln nht l 5m. t ct, cui si rt cht hoc t st rt cng c b dy t nht hng chc mt, tnh cht c hc tng dn theo su. t ct, cui si cht, cht va hoc t st cng c b dy ln t hng chc ti hng trm mt. t ri trng thi t xp n cht va (c hoc khng xen kp vi lp t dnh) hoc c a phn t dnh trng thi t mm n cng va. a tng bao gm lp t trm tch sng trn mt vi b dy trong khong 5-20m c gi tr tc truyn sng nh loi C, D v bn di l cc t cng hn vi tc truyn sng vs > 800m/s. a tng bao gm hoc cha mt lp t st mm/bn (bi) tnh do cao (PI> 40) v m cao, c chiu dy t nht l 10m. a tng bao gm cc t d ho lng, t st nhy hoc cc t khc vi cc t trong cc loi nn A-E hoc S1. < 100 (tham kho) >800

NSPT(nht/30cm)

cu (Pa) -

-

B

360-800

>50

>250

C

180-360

15-50

70 250 ls2 + eoy2, trong , bn knh qun tnh ls, bn knh xon rx , ry v cc lch tm ngu nhin eox , eoy c nh ngha trong 4.2.3.2(6).Ghi ch: Gi tr ca h s tm quan trng I , m di gi tr ny th cho php n gin ho phn tch theo 4.3.3.1(8), cho Ph lc F, Phn 1.

(9)

Kt cu nh tho mn tt c cc iu kin (8) ca mc ny nhng khng tho mn d), c th thc hin phn tch n hi-tuyn tnh bng cch s dng hai m hnh phng, mi m hnh cho mt phng ngang chnh. Trong nhng trng hp nh th, tt c cc h qu tc ng xc nh t nhng phn tch ny cn nhn vi 1,25.

(10)P

Kt cu nh khng tun th cc tiu ch t (7) n (9) ca mc ny phi c phn tch bng m hnh khng gian.

(11)P

Khi s dng m hnh khng gian, tc ng ng t thit k phi c t dc theo tt c cc phng nm ngang cn thit (xt theo cch b tr kt cu ca nh) v cc phng nm ngang vung gc vi chng. i vi nh c cc cu kin chu lc b tr theo hai phng vung gc th hai phng ny c xem l hai phng cn thit.

4.3.3.2. Phng php phn tch tnh lc ngang tng ng 4.3.3.2.1. Tng qut (1)P Phng php phn tch ny c th p dng cho cc nh m phn ng ca n khng chu nh hng ng k bi cc dng dao ng bc cao hn dng dao ng c bn trong mi phng chnh. (2) Yu cu (1)P ca iu ny c xem l tho mn nu kt cu nh p ng c c hai iu kin sau: a) C cc chu k dao ng c bn T1 theo hai hng chnh nh hn cc gi tr sau: 48

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4.T T1 C 2, 0 strong TC cho trong 3.2.2.2. b) Tho mn nhng tiu ch v tnh u n theo mt ng cho trong 4.2.3.3. 4.3.3.2.2. Lc ct y (1)P

(4.4)

Theo mi phng nm ngang c phn tch, lc ct y ng t Fb phi c xc nh theo biu thc sau: Fb = Sd (T1) . m . trong : Sd (T1) Tung ca ph thit k (xem 3.2.2.5) ti chu k T1; T1 m Chu k dao ng c bn ca nh do chuyn ng ngang theo phng ang xt; Tng khi lng ca nh trn mng hoc trn nh ca phn cng pha di, tnh ton theo 3.2.4(2); (4.5)

H s hiu chnh, ly nh sau:

= 0,85 nu T1 2 TC vi nh c trn 2 tng hoc = 1,0 vi cc trng hp khc.Ghi ch: H s tnh n thc t l trong cc nh c t nht 3 tng v 3 bc t do theo mi phng nm ngang, khi lng hu hiu ca dng dao ng c bn l trung bnh nh hn 15% so vi tng khi lng nh.

(2)

xc nh chu k dao ng c bnT1 ca nh, c th s dng cc biu thc ca cc phng php ng lc hc cng trnh (v d phng php Rayleigh).

(3)

i vi nh c chiu cao khng ln hn 40m, gi tr T1 (tnh bng s) c th tnh gn ng theo biu thc sau: T1 = Ct . H 3/4 trong : Ct = 0,085 i vi khung thp khng gian chu mmen; Ct =0,075 i vi khung btng khng gian chu mmen v khung thp c ging lch tm; Ct =0,050 i vi cc kt cu khc; (4.6)

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H (4)

chiu cao nh, tnh bng m, t mt mng hoc nh ca phn cng pha di.

i vi cc kt cu c tng chu ct bng btng hoc khi xy, gi tr Ct trong biu thc (4.6) c th ly bng: Ct= 0,075/ Ac trong : Ac = [ Ai . (0,2 + (lwi / H)) 2] v: Ac Ai tng din tch hu hiu ca cc tng chu ct trong tng u tin ca nh, tnh bng m2; din tch tit din ngang hu hiu ca tng chu ct i theo hng ang xt trong tng u tin ca nh, tnh bng m2; H nh trong (3) ca iu ny; (4.8)

(4.7)

lwi chiu di ca tng chu ct tng u tin theo hng song song vi cc lc tc ng, tnh bng m, vi iu kin: lwi /H khng c vt qu 0,9. (5) Mt cch khc c th xc nh T1 (s ) theo biu thc sau:

T1 = 2. dtrong : d

(4.9)

chuyn v ngang n hi ti nh nh, bng m, do cc lc trng trng tc dng theo phng ngang gy ra.

4.3.3.2.3. Phn b lc ng t nm ngang (1) Cc dng dao ng c bn theo cc phng nm ngang c xt ca nh c th c xc nh bng cc phng php ng lc hc cng trnh hoc c th ly gn ng bng cc chuyn v ngang tng tuyn tnh dc theo chiu cao ca nh. (2)P Tc ng ng t phi c xc nh bng cch t cc lc ngang Fi vo tt c cc tng hai m hnh phng

si.mi sj .mj , Fi = Fb .trong :

(4.10)

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Fi Fb si , sj

lc ngang tc dng ti tng th i; lc ct y do ng t tnh theo (4.5); ln lt l chuyn v ca cc khi lng mi , mj trong dng dao ng c bn;

mi, mj khi lng ca cc tng tnh theo 3.2.4 (2). (3) Khi dng dao ng c bn c ly gn ng bng cc chuyn v nm ngang tng tuyn tnh dc theo chiu cao th lc ngang Fi tnh bng:

zi .mi z j .mj Fi = Fb .trong : zi; zj

(4.11)

cao ca cc khi lng mi, mj so vi im t tc ng ng t (mt mng hoc nh ca phn cng pha di).

(4)P

Lc nm ngang Fi xc nh theo iu ny phi c phn b cho h kt cu chu ti ngang vi gi thit sn cng trong mt phng ca chng.

4.3.3.2.4. Hiu ng xon (1) Nu cng ngang v khi lng phn b i xng trong mt bng v tr phi lch tm ngu nhin nu trong 4.3.2(1)P c xt n bng mt phng php chnh xc hn (v d nh phng php trong 4.3.3.3.3(1)), th cc hiu ng xon ngu nhin c th c xc nh bng cch nhn cc h qa tc ng trong cc cu kin chu lc ring l tnh theo 4.3.3.2.3(4) vi mt h s cho bi:

= 1 + 0,6 (x/Le)trong : x

(4.12)

khong cch t cu kin ang xt n tm khi lng ca nh trong mt bng theo phng vung gc vi phng tc ng ng t ang xt.

Le

khong cch gia hai cu kin chu ti ngang xa nhau nht, theo phng vung gc vi phng tc ng ng t ang xt.

(2)

Nu thc hin phn tch bng cch s dng hai m hnh phng, mi m hnh cho mt phng ngang chnh th hiu ng xon c th xc nh bng cch nhn i lch tm ngu nhin eai tnh theo (4.3) v p dng (1) ca iu ny vi h s bng 1,2 thay cho 0,6 trong biu thc (4.12).

4.3.3.3. Phn tch ph phn ng dng dao ng 51

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4.3.3.3.1. Tng qut. (1)P Phng php phn tch ny cn c p dng cho nh khng tho mn nhng iu kin nu trong 4.3.3.2.1(2) khi ng dng phng php phn tch tnh lc ngang tng ng. (2)P Phi xt ti phn ng ca tt c cc dng dao ng gp phn ng k vo phn ng tng th ca nh. (3) Cc yu cu cho trong mc (2)P c th tho mn nu t c mt trong hai iu kin sau: - Tng cc khi lng hu hiu ca cc dng dao ng c xt chim t nht 90% tng khi lng ca kt cu; - Tt c cc dng dao ng c khi lng hu hiu ln hn 5% ca tng khi lng u c xt n.Ghi ch: Khi lng hu hiu mk ng vi dng dao ng k, c xc nh sao cho lc ct y Fbk, tc ng theo phng tc ng ca lc ng t, c th biu th di dng Fbk = Sd (Tk) mk. C th chng minh rng tng cc khi lng hu hiu (i vi tt c cc dng dao ng v i vi mt hng cho trc) l bng khi lng kt cu.

(4)

Khi s dng m hnh khng gian, nhng iu kin trn cn c kim tra cho mi phng cn thit.

(5)

Nu cc yu cu quy nh trong (3) khng th tho mn (v d trong nh v cng trnh m cc dao ng xon gp phn ng k) th s lng ti thiu cc dng dao ng k c xt trong tnh ton khi phn tch khng gian cn tho mn c hai iu kin sau: k3 n v Tk 0,20 s. trong : k n Tk s dng dao ng c xt ti trong tnh ton; s tng trn mng hoc nh ca phn cng pha di; chu k dao ng ca dng th k. (4.14) (4.13)

4.3.3.3.2. T hp cc phn ng dng dao ng

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(1)

Phn ng hai dng dao ng i v j (k c cc dng dao ng tnh tin v xon) c th xem l c lp vi nhau, nu cc chu k Ti v Tj tho mn iu kin sau: Tj 0,9 . Ti (4.15)

(2)

Khi tt c cc dng dao ng cn thit (xem 4.3.3.3.1(3)-(5)) c xem l c lp vi nhau, th gi tr ln nht EE ca h qu tc ng ng t c th ly bng:

EE =

E

2 Ei

(4.16)

trong : EE EEi (3)P h qu tc ng ng t ang xt (lc, chuyn v, vv..); gi tr ca h qu tc ng ng t ny do dng dao ng th i gy ra.

Nu (1) khng tho mn, cn thc hin cc quy trnh chnh xc hn t hp cc phn ng cc i ca cc dng dao ng, v d nh cch T hp bc hai y .

4.3.3.3.3. Hiu ng xon. (1) Khi s dng m hnh khng gian phn tch, c th xc nh cc hiu ng xon ngu nhin nu trong 4.3.2(1)P di dng gi tr bao ca nhng hiu ng do cc ti trng tnh, gm tp hp cc mmen xon Mai xung quanh trc thng ng mi tng th i: Mai = eai . Fi trong : Mai eai mmen xon tc dng ti tng th i quanh trc thng ng ca tng; lch tm ngu nhin ca khi lng tng th i theo biu thc (4.3) i vi tt c cc phng cn thit; Fi lc nm ngang tc ng ln tng th i, theo mi phng cn thit, nh nu trong 4.3.3.2.3. (2) Cc hiu ng ca ti trng ph hp vi (1) cn c xt vi du dng v m (cng du cho tt c cc tng). (3) Khi s dng hai m hnh phng ring bit phn tch, c th xt hiu ng xon bng cch p dng cc quy nh ca 4.3.3.2.4(2) i vi cc h qu tc ng c tnh theo 4.3.3.3.2. 4.3.3.4. Cc phng php phi tuyn 4.3.3.4.1. Tng qut 53 (4.17)

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(1)P

M hnh ton hc c s dng trong phn tch n hi phi c m rng c th xt ti bn ca cc cu kin chu lc v ng x sau n hi ca chng.

(2)

mc cu kin, t nht phi dng quan h lc-bin dng hai on thng. Trong nh btng ct thp v nh xy, cng n hi ca quan h lc-bin dng hai on thng cn phi tng ng vi cng ca cc tit din b nt (xem 4.3.1(7)). Trong cc cu kin c tnh do kt cu c gi thit lm vic sau gii hn chy, cng n hi ca quan h hai on thng l cng ct tuyn i vi im chy do. Cho php s dng quan h lc - bin dng ba on thng c tnh n cng trc v sau khi nt.

(3)

C th gi thit cng sau giai on chy do bng khng. Nu s suy gim cng xy ra, v d nh vi cc tng xy hoc cc cu kin gin khc th phi xt s suy gim y trong quan h lc - bin dng ca cc cu kin .

(4)

Tr phi c cc quy nh khc, cc tnh cht ca cu kin cn da vo cc gi tr trung bnh ca tham s vt liu. i vi kt cu mi, cc gi tr trung bnh ca tham s vt liu c th xc nh t cc gi tr c trng tng ng trn c s nhng thng tin cho trong EN 1992 n EN 1996 hoc trong cc tiu chun hin hnh khc.

(5)P

Cc lc trng trng theo 3.2.4 phi c t vo cc phn t thch hp ca m hnh tnh ton.

(6)

Khi xc nh quan h lc - bin dng cho cc cu kin chu lc, cn xt cc lc dc gy ra bi lc trng trng. C th b qua mmen un gy ra bi lc trng trng trong cc cu kin thng ng chu lc, tr phi chng nh hng ln ti ng x tng th ca kt cu.

(7)P

Tc ng ng t phi c t theo c hai hng dng v m v phi s dng kt qu l cc h qu ng t ln nht.

4.3.3.4.2. Phn tch tnh phi tuyn (y dn) 4.3.3.4.2.1. Tng qut (1) Phn tch y dn l phn tch tnh phi tuyn c thc hin di iu kin lc trng trng khng i v ti trng nm ngang tng mt cch n iu. Phng php ny c th p dng kim tra tnh nng kt cu ca nh hin hu v nh c thit k mi vi nhng mc ch sau: a) kim tra hoc nh gi li cc t s vt cng u/1 (xem 5.2.2.2.1, 6.3.2, 7.3.2); b) xc nh cc c cu do d kin v s phn b h hng; c) nh gi tnh nng kt cu ca nh hin hu hoc c ci to theo cc mc tiu ca tiu chun lin quan;

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d) S dng nh mt phng php thit k thay cho phng php phn tch n hi-tuyn tnh c s dng h s ng x q. Trong trng hp , chuyn v mc tiu cho trong 4.3.3.4.2.6(1)P cn c s dng lm c s thit k. (2)P Cc cng trnh khng tho mn nhng tiu ch v tnh u n trong 4.2.3.2 hoc trong 4.3.3.1(8)a)-d) phi c phn tch bng m hnh khng gian. C th s dng hai phn tch c lp trong cc ti trng ngang ch tc dng theo mt phng. (3) i vi cc nh tun theo nhng tiu ch v tnh u n trong 4.2.3.2 hoc trong 4.3.3.1(8)a)-d) c th phn tch bng hai m hnh phng, mi m hnh cho mt phng nm ngang chnh. (4) i vi cc nh khi xy thp tng, trong cc tng ch yu chu ct th mi tng c th c phn tch mt cch c lp. (5) Nhng yu cu trong (4) c xem l tho mn nu s lng tng khng ln hn 3 v nu t s hnh dng trung bnh (chiu cao trn chiu rng) ca cc tng chu lc nh hn 1,0. 4.3.3.4.2.2. Ti trng ngang (1) Cn p dng t nht hai cch phn b theo phng ng ca cc ti trng ngang theo hai s sau: - S u, da trn cc lc ngang t l vi khi lng, khng i theo chiu cao (gia tc phn ng u); - S dng dao ng, t l vi cc lc ngang tng ng vi s phn b lc ngang theo phng ang xt, s phn b ny c xc nh trong phn tch n hi (theo 4.3.3.2 hoc 4.3.3.3). (2)P Cc ti trng ngang phi t ti v tr cc khi lng trong m hnh. Phi xt ti lch tm ngu nhin theo 4.3.2(1)P. 4.3.3.4.2.3. ng cong lc chuyn v (1) Mi quan h gia lc ct y v chuyn v khng ch (ng cong lc - chuyn v) cn c xc nh bng phn tch y dn i vi cc gi tr ca chuyn v khng ch nm trong phm vi t 0 n gi tr ng vi 150% chuyn v mc tiu, xc nh trong 4.3.3.4.2.6. (2) Chuyn v khng ch c th ly tm khi lng ca mi nh. nh ca nh xy trn mi khng c xem l mi nh. 4.3.3.4.2.4. H s vt cng (1) Khi xc nh t s vt cng (u/1) bng phn tch y dn, cn s dng gi tr nh hn ca t s vt cng xc nh t hai s phn b ti trng ngang. 55

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4.3.3.4.2.5. C cu do (1)P C cu do phi c xc nh cho c hai s phn b ti trng ngang. Cc c cu do phi ph hp vi cc c cu dng xc nh h s ng x q s dng trong thit k. 4.3.3.4.2.6. Chuyn v mc tiu (1)P Chuyn v mc tiu phi c nh ngha nh mt yu cu khng chn di dng chuyn v ca h mt bc t do tng ng xc nh t ph phn ng n hi theo 3.2.2.2.Ghi ch: Ph lc tham kho B cho quy trnh xc nh chuyn v mc tiu theo ph phn ng n hi.

4.3.3.4.2.7. Quy trnh xc nh hiu ng xon (1)P Phn tch y dn thc hin vi cc s lc cho trong 4.3.3.4.2.2 c th nh gi qu thp cc bin dng ti pha cng hn ca kt cu d xon, c ngha l kt cu c dng dao ng c bn m xon chim u th. iu ny cng ng vi cc bin dng ti pha cng hn theo mt phng ca kt cu c dng dao ng th hai m xon chim u th. i vi cc kt cu nh vy, cc chuyn v ti pha cng hn phi c tng ln so vi chuyn v ca kt cu tng ng cn bng v xon.Ghi ch: Pha cng hn trong mt bng l pha c chuyn v nm ngang nh hn so vi pha t cng

hn di tc ng ca ti trng ngang tnh song song vi n. i vi cc kt cu d xon,cc chuyn v ng pha cng hn c th tng ln ng k do nh hng ca dng dao ng xon chim u th.

(2)

Yu cu quy nh trong (1) ca mc ny c xem l tho mn nu h s khuch i p dng cho cc chuyn v ca pha cng hn c da trn cc kt qu phn tch dng dao ng n hi bng m hnh khng gian.

(3)

Nu s dng hai m hnh phng phn tch kt cu c tnh u n trong mt bng th cc hiu ng xon c th xc nh theo 4.3.3.2.4 hoc 4.3.3.3.3.

4.3.3.4.3. Phn tch phi tuyn theo lch s thi gian (1) Phn ng ph thuc thi gian ca kt cu c th xc nh bng cch phn tch theo lch s thi gian cc phng trnh vi phn chuyn ng ca n, s dng cc gin gia tc biu th cc chuyn ng nn cho trong 3.2.3.1. (2) Cc m hnh kt cu cn tun theo cc yu cu t (2) n (4) trong 4.3.3.4.1 v cn c b sung bng nhng quy nh m t ng x ca cc phn t khi chu cc chu k cht- d ti sau giai on n hi. Nhng qui nh ny cn phn nh xc thc s tiu tn nng lng ca phn t trong min bin chuyn v c th xy ra khi thit k chu ng t.

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(3)

Nu phn ng c xc nh t nht t 7 phn tch phi tuyn theo lch s thi gian vi cc chuyn ng nn theo 3.2.3.1, th tr trung bnh ca cc gi tr phn ng t tt c cc phn tch cn c s dng nh gi tr thit k ca h qu tc ng Ed trong nhng kim tra cn thit theo 4.4.2.2. Trong trng hp tri ngc cn ly gi tr bt li nht ca gi tr phn ng trong cc phn tch l Ed.

4.3.3.5. T hp cc h qu ca cc thnh phn tc ng ng t 4.3.3.5.1 Cc thnh phn nm ngang ca tc ng ng t (1)P Ni chung, cc thnh phn nm ngang ca tc ng ng t (xem 3.2.2.1(3)) phi c xem l tc ng ng thi. (2) Vic t hp cc thnh phn nm ngang ca tc ng ng t c th thc hin nh sau: a) Phn ng kt cu i vi mi thnh phn phi c xc nh ring r bng cch s dng nhng quy tc t hp i vi cc phn ng dng dao ng theo 4.3.3.3.2. b) Gi tr ln nht ca mi h qu tc ng ln kt cu do hai thnh phn nm ngang ca tc ng ng t, c th xc nh bng cn bc hai ca tng bnh phng cc gi tr ca h qu tc ng do mi thnh phn nm ngang gy ra. c) Quy tc b) trn ni chung cho kt qu thin v an ton ca cc gi tr c th c ca cc h qu tc ng khc ng thi vi gi tr ln nht thu c nh trong b). C th s dng cc m hnh chnh xc hn xc nh cc gi tr c th c ng thi t nhiu h qu tc ng do hai thnh phn nm ngang ca tc ng ng t gy ra. (3) Nu khng dng b) v c) ca (2) trong iu ny, cc h qu tc ng do t hp cc thnh phn nm ngang ca tc ng ng t c th xc nh bng cch s dng c hai t hp sau: a) b) Trong : + c ngha l t hp vi; EEdx biu th cc h qu tc ng do t tc ng ng t dc theo trc nm ngang x c chn ca kt cu; EEdy biu th cc h qu tc ng do t tc ng ng t dc theo trc nm ngang y vung gc ca kt cu. EEdx + 0,30 EEdy 0,30EEdx + EEdy (4.18) (4.19)

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(4)

Nu theo cc phng nm ngang khc nhau, h kt cu hoc s phn loi tnh u n ca nh theo mt ng l khc nhau, th gi tr h s ng x q cng c th khc nhau.

(5)P

Du ca mi thnh phn trong cc t hp k trn phi ly l du bt li nht i vi h qu tc ng ring ang xt.

(6)

Khi s dng phn tch tnh phi tuyn (y dn) v m hnh kt cu khng gian, cn p dng cc quy tc t hp (2), (3) ca iu ny, xem EEdx l cc lc v bin dng do dng chuyn v mc tiu theo phng x v EEdy l cc lc v bin dng do dng chuyn v mc tiu theo phng y. Cc ni lc c c t t hp ny khng c vt qu cc kh nng tng ng.

(7)P

Khi s dng phn tch phi tuyn theo thi gian v m hnh kt cu khng gian, cc gin gia tc tc ng ng thi phi c xem l tc ng theo c hai phng nm ngang.

(8)

i vi nh tho mn cc tiu ch v tnh u n trong mt bng, trong cc tng hoc cc h ging c lp theo hai phng nm ngang chnh l cc cu kin khng chn chnh duy nht (xem 4.2.2), th tc ng ng t dc theo hai trc ngang nm chnh vung gc ca kt cu c th c gi thit tc ng ring r v khng dng nhng t hp (2), (3) ca iu ny.

4.3.3.5.2. Thnh phn thng ng ca tc ng ng t (1) Nu avg ln hn 0,25g (2,5 m/s2) th thnh phn thng ng ca tc ng ng t, nh nh ngha trong 3.2.2.3 cn c xt trong cc trng hp sau: Cc b phn kt cu nm ngang hoc gn nh nm ngang c nhp bng hoc ln hn 20m; Cc thnh phn kt cu dng cngxn nm ngang hoc gn nh nm ngang di hn 5 m; Cc thnh phn kt cu ng lc trc nm ngang hoc gn nh nm ngang; Cc dm ct; Cc kt cu c cch chn y.

(2)

Vic phn tch xc nh cc h qu ca thnh phn thng ng ca tc ng ng t c th da trn m hnh khng y ca kt cu, bao gm cc cu kin chu tc dng ca thnh phn ng t thng ng (v d nh cc thnh phn kt cu lit k trong (1) ca iu ny) v c xt ti cng ca cc cu kin lin k.

(3)

Cn a vo tnh ton cc h qu ca thnh phn thng ng ch i vi cc cu kin ang xt (v d cc cu kin lit k trong (1) ca mc ny) v cc cu kin hoc cu kin kt cu lin quan trc tip vi chng.

(4)

Nu cc thnh phn nm ngang ca tc ng ng t cng c xt n cho cc cu kin ny, c th p dng nhng quy nh trong 4.3.3.5.1(2) v m rng cho 3 thnh phn tc

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ng ng t. Ni cch khc, c th s dng tt c ba t hp sau tnh ton cc h qu tc ng: a) b) c) EEdx + 0,30 EEdy + 0,30 EEdz 0,30 EEdx + EEdy + 0,30 EEdz 0,30 EEdx + 0,30 EEdy + EEdz (4.20) (4.21) (4.22)

Trong : + c ngha l t hp vi; EEdx v EEdy nh trong 4.3.3.5.1(3); EEdz biu th cc h qu tc ng do tc dng ca thnh phn thng ng ca tc ng ng t thit k nh nh ngha trong (5) v (6) ca 3.2.2.5. (5) Nu thc hin phn tch tnh phi tuyn (y dn), th c th b qua thnh phn ng ca tc ng ng t. 4.3.4. (1)P Tnh ton chuyn v Nu thc hin phn tch tuyn tnh th cc chuyn v gy ra bi tc ng ng t thit k phi c tnh ton trn c s cc bin dng n hi ca h kt cu bng biu thc n gin sau: ds = qd dc trong : ds qd dc chuyn v ca mt im ca h kt cu gy ra bi tc ng ng t thit k; h s ng x chuyn v, gi thit bng q tr phi c quy nh khc; chuyn v ca cng im ca h kt cu c xc nh bng phn tch tuyn tnh da trn ph phn ng thit k theo 3.2.2.5. Gi tr ca ds khng nht thit phi ln hn gi tr xc nh t ph n hi.Ghi ch: Ni chung qd ln hn q nu chu k c bn ca kt cu nh hn TC (xem Hnh B2).

(4.23)

(2)P (3)

Khi xc nh cc chuyn v dc, phi xt ti cc hiu ng xon ca tc ng ng t. i vi c phn tch tnh v ng phi tuyn, cc chuyn v c xc nh l cc chuyn v nhn trc tip t phn tch m khng cn chnh l g thm.

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4.3.5.

B phn phi kt cu

4.3.5.1. Tng qut (1)P Cc kin phi kt cu ca nh (v d: tng chn mi, tng u hi, ct ng ten, thit b v ph kin c kh, tng bao, tng ngn, lan can) m trong trng hp sp c th gy nguy him cho ngi hoc nh hng ti kt cu chnh ca cng trnh hoc ti hot ng ca cc thit b quan trng, phi c kim tra kh nng chu tc ng ng t thit k cng vi gi chng. (2)P i vi cc b phn phi kt cu c tm quan trng ln hoc c tnh cht nguy him c bit th vic phn tch khng chn phi da vo mt m hnh thc ca cc kt cu ang xt v s dng cc ph phn ng thch hp thu c t phn ng ca cc cu kin ca h kt cu khng chn chnh. (3) Trong tt c cc trng hp khc, nu c l do xc ng th c php n gin ho quy trnh ny (nh trong 4.3.5.2(2)). 4.3.5.2. Kim tra (1)P Cc b phn phi kt cu, cng nh cc lin kt v phn g lp hoc neo gi chng, phi c kim tra khi thit k chu ng t (xem 3.2.4).Ghi ch: Cn xt ti s truyn dn cc b ca cc tc ng ti kt cu chnh thng qua lin kt cht vi cc b phn phi kt cu v cc nh hng ca cc cu kin ny ti ng x ca kt cu. Cc yu cu v lin kt cht vo btng c cho trong EN 1992-1-1:2004, 2.7.

(2)

C th xc nh cc h qu tc ng ng t bng cch tc dng vo b phn phi kt cu mt lc nm ngang Fa xc nh nh sau: Fa = (Sa . Wa . a) /qa trong : Fa lc ng t ngang, tc dng ti tm khi lng ca b phn phi kt cu theo phng bt li nht; Wa Sa trng lng ca cu kin; h s ng t dng cho b phn phi kt cu (xem (3) ca iu ny); h s tm quan trng ca cu kin, xem 4.3.5.3; h s ng x ca cu kin; xem Bng 4.3; (4.24)

aqa (3) 60

H s ng t Sa c th tnh bng biu thc sau:

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Sa = .S. [3(1 + z/H) / (1 + (1 Ta/T1)2) 0,5] trong :

(4.25)

S Ta T1 z

t s gia gia tc nn thit k ag trn nn t loi A, vi gia tc trng trng g; h s nn; chu k dao ng c bn ca b phn phi kt cu; chu k dao ng c bn ca cng trnh theo hng cn thit; cao ca b phn phi kt cu k t im t lc tc ng ng t (mt mng hoc nh ca phn cng pha di);

H

chiu cao cng trnh tnh t mt mng hoc t nh ca phn cng pha di.

Gi tr h s ng t Sa khng c nh hn .S . 4.3.5.3. H s tm quan trng. (1)P H s tm quan trng a khng c nh hn 1,5 i vi cc b phn phi kt cu sau: Cc b phn neo gi ca thit b my mc cn thit cho h thng bo m an ton cuc

sng; B cha v thng cha cht c hoc cht gy n xem l nguy him cho s an t