03-TCXDVN 375 2006 Thiet ke cong trinh chiu dong dat.pdf

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TCXDVN Tiu chun xy dng Vit nam

TCXDVN 375 : 2006 Xut bn ln 1

Thit k cng trnh chu ng t

Design 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

ICIC KIM SOT 27/06/2008

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mc lc

Li ni u ................................................................................................................................................. 1

1. Tng qut......................................................................................................................................... 3

1.1. Phm vi p dng...............................................................................................................................3

1.1.1. Phm vi p dng ca tiu chun: Thit k cng trnh chu ng t............................................... 3

1.1.2. Phm vi p dng ca phn 1............................................................................................................3

1.2. Cc ti liu tham kho v tiu chun ...............................................................................................4

1.2.1. Cc tiu chun tham kho chung.....................................................................................................4

1.2.2. Nhng Quy chun v Tiu chun tham kho khc..........................................................................5

1.3. Cc gi thit ...................................................................................................................................... 5

1.4. S phn bit gia cc nguyn tc v cc quy nh p dng ...........................................................5

1.5. Thut ng v nh ngha ...................................................................................................................6

1.5.1. Thut ng chung...............................................................................................................................6

1.5.2. Cc thut ng khc c s dng trong tiu chun ........................................................................6

1.6. K hiu .............................................................................................................................................. 7

1.6.1. Tng qut.......................................................................................................................................... 7

1.6.2. Cc k hiu khc c s dng trong chng 2 v chng 3.......................................................... 7

1.6.3. Cc k hiu khc c s dng trong chng 4...............................................................................8

1.6.4. Cc k hiu khc c s dng trong chng 5...............................................................................9

1.6.5. Cc k hiu khc c s dng trong chng 6.............................................................................14




1.6.9. Cc k hiu khc c s dng trong chng 10...........................................................................19

1.7. n v SI..........................................................................................................................................19

2. Yu cu v tnh nng v cc tiu ch cn tun theo.................................................................21

2.1. Nhng yu cu c bn....................................................................................................................21


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2.2. Cc tiu ch cn tun theo ..............................................................................................................22

2.2.1. Tng qut........................................................................................................................................22

2.2.2. Trng thi cc hn ..........................................................................................................................23

2.2.3. Trng thi hn ch h hng ...........................................................................................................23

2.2.4. Cc bin php c th......................................................................................................................24

3. iu kin nn t v tc ng ng t....................................................................................25

3.1. iu kin nn t............................................................................................................................25

3.1.1. Tng qut........................................................................................................................................25

3.1.2. Nhn dng cc loi nn t............................................................................................................25

3.2. Tc ng ng t..........................................................................................................................27

3.2.1. Cc vng ng t .........................................................................................................................27

3.2.2. Biu din c bn ca tc ng ng t........................................................................................27

3.2.3. Nhng cch biu din khc ca tc ng ng t.......................................................................32

3.2.4. Cc t hp tc ng ng t vi cc tc ng khc ....................................................................34

4. Thit k nh...................................................................................................................................36

4.1. Tng qut........................................................................................................................................36

4.1.1. Phm vi p dng.............................................................................................................................36

4.2. Cc c trng ca cng trnh chu ng t ..................................................................................36

4.2.1. Nhng nguyn tc c bn ca thit k c s .................................................................................36

4.2.2. Cc cu kin khng chn chnh v ph .........................................................................................38

4.2.3. Tiu ch v tnh u n ca kt cu..............................................................................................39

4.2.4. Cc h s t hp ca tc ng thay i.........................................................................................42

4.2.5. Mc v h s tm quan trng....................................................................................................43

4.3. Phn tch kt cu ............................................................................................................................43

4.3.1. M hnh ...........................................................................................................................................43

4.3.2. Hiu ng xon ngu nhin .............................................................................................................44

4.3.3. Cc phng php phn tch ...........................................................................................................44

4.3.4. Tnh ton chuyn v.........................................................................................................................56

4.3.5. B phn phi kt cu ........................................................................................................................56

4.3.6. Cc bin php b sung i vi khung c khi xy chn................................................................58


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4.4. Kim tra an ton .............................................................................................................................61

4.4.1. Tng qut........................................................................................................................................61

4.4.2. Trng thi cc hn ..........................................................................................................................61

4.4.3. Hn ch h hng ............................................................................................................................65

5. Nhng quy nh c th cho kt cu btng..............................................................................67

5.1. Tng qut........................................................................................................................................67

5.1.1. Phm vi p dng.............................................................................................................................67

5.1.2. Thut ng v nh ngha .................................................................................................................67

5.2. Quan nim thit k..........................................................................................................................69

5.2.1. Kh nng tiu tn nng lng v cc cp do kt cu..................................................................69

5.2.2. Loi kt cu v h s ng x..........................................................................................................70

5.2.3. Tiu ch thit k...............................................................................................................................73

5.2.4. Kim tra mc an ton ................................................................................................................76

5.3. Thit k theo EN 1992-1-1 .............................................................................................................77

5.3.1. Tng qut........................................................................................................................................77

5.3.2. Vt liu ............................................................................................................................................77

5.3.3. H s ng x...................................................................................................................................77

5.4. Thit k cho trng hp cp do kt cu trung bnh......................................................................77

5.4.1. Vt liu v kch thc hnh hc .......................................................................................................77

5.4.2. H qu tc ng thit k.................................................................................................................79

5.4.3. Kim tra v cu to theo trng thi cc hn...................................................................................84

5.5. Thit k cho trng hp cp do kt cu cao ................................................................................95

5.5.1. Vt liu v kch thc hnh hc .......................................................................................................95

5.5.2. H qu tc ng thit k.................................................................................................................96

5.5.3. Kim tra theo trng thi cc hn v cu to...................................................................................98

5.6. Cc yu cu v neo v mi ni ....................................................................................................108

5.6.1. Tng qut......................................................................................................................................108

5.6.2. Neo ct thp..................................................................................................................................109

5.6.3. Ni cc thanh ct thp ..................................................................................................................110

5.7. Thit k v cu to cc cu kin khng chn ph.......................................................................111

5.8. Cc b phn ca mng btng ....................................................................................................112


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5.8.1. Phm vi .........................................................................................................................................112

5.8.2 Dm ging v dm ging mng ...................................................................................................113

5.8.3. Mi ni cc cu kin thng ng vi dm mng hoc tng ......................................................113

5.8.4. Cc v i cc btng c ti ch ...............................................................................................114

5.9. nh hng cc b do tng chn bng khi xy hoc btng ...................................................114

5.10. Yu cu i vi tm cng bng btng........................................................................................115

5.11. Kt cu btng c sn................................................................................................................116

5.11.1 Tng qut......................................................................................................................................116

5.11.2. Mi ni cc cu kin c sn .......................................................................................................120

5.11.3. Cu kin........................................................................................................................................121

6. Nhng quy nh c th cho kt cu thp ................................................................................125

6.1. Tng qut......................................................................................................................................125

6.1.1 Phm vi p dng.................................................................................................................. 125

6.1.2 Cc quan nim thit k ........................................................................................................ 125

6.1.3 Kim tra an ton ............................................................................................................. 126

6.2. Vt liu ..........................................................................................................................................126

6.3. Dng kt cu v h s ng x......................................................................................................127

6.3.1 Cc dng kt cu................................................................................................................. 127

6.3.2 H s ng x........................................................................................................................ 131

6.4. Phn tch kt cu ..........................................................................................................................132

6.5. Cc tiu ch thit k v quy nh cu to cho mi loi kt cu c kh nng tiu tn nng lng ....................................................................................................................................132

6.5.1 Tng qut............................................................................................................................. 132

6.5.2 Cc tiu ch thit k cho kt cu c kh nng tiu tn nng lng...................................... 132

6.5.3 Cc quy nh thit k cho nhng cu kin c kh nng tiu tn nng lng lm vic chu nn hoc un ........................................................................................................ 133

6.5.4 Cc quy nh thit k cho cc b phn hoc cu kin chu ko .......................................... 133

6.5.5 Cc quy nh thit k cho nhng lin kt trong vng tiu tn nng lng ........................... 133

6.6. Cc quy nh c th cho thit k khung chu mmen ..................................................................134

6.6.1 Cc tiu ch thit k ............................................................................................................. 134

6.6.2 Dm ..................................................................................................................................... 134

6.6.3 Ct ....................................................................................................................................... 135


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6.6.4 Lin kt dm - ct ................................................................................................................ 136

6.7. Thit k v cc quy nh cu to cho khung vi h ging ng tm...........................................138

6.7.1 Tiu ch thit k.................................................................................................................... 138

6.7.2 Php phn tch..................................................................................................................... 138

6.7.3 Cc thanh ging cho.......................................................................................................... 139

6.7.4 Dm v ct........................................................................................................................... 140

6.8. Thit k v cc quy nh cu to cho khung c h ging lch tm .............................................141

6.8.1 Cc tiu ch thit k ............................................................................................................. 141

6.8.2 Cc on ni khng chn .................................................................................................... 141

6.8.3 Cc cu kin khng c on ni khng chn ...................................................................... 144

6.8.4 Lin kt ca cc on ni khng chn ................................................................................ 145

6.9. Cc quy nh thit k cho kt cu kiu con lc ngc .................................................................146

6.10. 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.........................................146

6.10.1 Kt cu c li btng hoc vch btng.............................................................................. 146

6.10.2 Khung chu mmen kt hp vi h ging ng tm............................................................. 146

6.10.3 Khung chu mmen kt hp vi tng chn......................................................................... 146

6.11. Qun l thit k v thi cng ..........................................................................................................147

7. Nhng quy nh c th cho kt cu lin hp thp - btng..................................................148

7.1 Tng qut............................................................................................................................. 148

7.1.2 Phm vi p dng.................................................................................................................. 148

7.1.2 Cc quan nim thit k ........................................................................................................ 148

7.1.3 Kim tra an ton ............................................................................................................. 149

7.2 Vt liu................................................................................................................................. 149

7.2.1 Btng ................................................................................................................................. 149

7.2.2 Ct thp trong btng .......................................................................................................... 150

7.2.3 Kt cu thp......................................................................................................................... 150

7.3 Dng kt cu v h s ng x ............................................................................................. 150

7.3.1 Dng kt cu........................................................................................................................ 150

7.3.2 H s ng x........................................................................................................................ 152

7.4 Phn tch kt cu ................................................................................................................. 152

7.4.1 Phm vi................................................................................................................................ 152


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7.4.2 cng ca tit din ........................................................................................................... 153

7.5 Cc tiu ch thit k v quy nh cu to cho mi loi kt cu c kh nng tiu tn nng lng..................................................................................................................................... 153

7.5.1 Tng quan............................................................................................................................ 153

7.5.2 Cc tiu ch thit k i vi kt cu c kh nng tiu tn nng lng ................................. 153

7.5.3 bn do ca cc vng tiu tn nng lng .................................................................... 154

7.5.4 Cc quy nh cu to cho lin kt lin hp trong vng tiu tn nng lng......................... 154

7.6 Cc quy nh cho cu kin................................................................................................... 156

7.6.1 Tng qut............................................................................................................................. 156

7.6.2 Dm thp lin hp vi bn ................................................................................................... 159

7.6.3 Chiu rng hu hiu ca bn............................................................................................... 160

7.6.4 Ct lin hp c bao bc hon ton ................................................................................. 161

7.6.5 Cu kin c bc btng mt phn ................................................................................... 164

7.6.6 Ct thp nhi btng ........................................................................................................... 166

7.7 Cc quy nh c th cho thit k khung chu mmen .......................................................... 166

7.7.1 Cc tiu ch ring ................................................................................................................. 166

7.7.2 Php phn tch..................................................................................................................... 166

7.7.3 Cc quy nh cho dm v ct .............................................................................................. 167

7.7.4 Lin kt dm ct ............................................................................................................... 167

7.7.5 iu kin b qua c trng lin hp ca dm vi bn.................................................... 167

7.8 Cc quy nh thit k v cu to cho khung lin hp vi ging ng tm ........................... 167

7.8.1 Cc tiu ch c th ............................................................................................................... 167

7.8.2 Phng php phn tch........................................................................................................ 168

7.8.3 Cc cu kin ging cho ..................................................................................................... 168

7.8.4 Dm v ct........................................................................................................................... 168

7.9 Cc quy nh thit k v cu to cho khung lin hp vi ging lch tm ............................ 168

7.9.1 Cc tiu ch ring ................................................................................................................. 168

7.9.2 Php phn tch..................................................................................................................... 168

7.9.3 on ni .............................................................................................................................. 168

7.9.4 Cu kin khng cha on ni khng chn......................................................................... 169

7.10 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................................................................... 169

7.10.1 Cc tiu ch .......................................................................................................................... 169


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7.10.2 Php phn tch..................................................................................................................... 171

7.10.3 Cc quy nh cu to cho tng lin hp thuc cp do kt cu trung bnh DCM ............. 171

7.10.4 Cc quy nh cu to cho dm ni thuc cp do kt cu trung bnh DCM ........................ 172

7.10.5 Cc quy nh cu to cho cp do kt cu cao DCH .......................................................... 172

7.11 Cc quy nh thit k v cu to cho vch cng lin hp dng tm thp bc btng.................................................................................................................................. 172

7.12 Kim sot thit k v thi cng.............................................................................................. 173

8. Nhng quy nh c th cho kt cu g....................................................................................174

8.1 Tng qut............................................................................................................................. 174

8.1.1 Phm vi p dng.................................................................................................................. 174

8.1.2 Cc nh ngha..................................................................................................................... 174

8.1.3 Cc quan nim thit k ........................................................................................................ 174

8.2 Vt liu v cc c trng ca vng tiu tn nng lng ...................................................... 175

8.3 Cp do kt cu v h s ng x ........................................................................................ 176

8.4 Phn tch kt cu ................................................................................................................. 177

8.5 Cc quy nh cu to ........................................................................................................... 177

8.5.1 Tng qut............................................................................................................................. 177

8.5.2 Nhng quy nh cu to cho lin kt.................................................................................... 177

8.5.3 Cc quy nh cu to cho tm cng nm ngang ................................................................. 178

8.6 Kim tra an ton ............................................................................................................. 178

8.7 Kim sot thit k v thi cng.............................................................................................. 179

9. Nhng quy nh c th cho kt cu xy..................................................................................180

9.1 Phm vi p dng.................................................................................................................. 180

9.2 Vt liu v kiu lin kt ........................................................................................................ 180

9.2.1 Cc loi vin xy.................................................................................................................. 180

9.2.2 Cng nh nht ca vin xy ......................................................................................... 180

9.2.3 Va xy................................................................................................................................ 180

9.2.4 Kiu xp vin xy................................................................................................................. 180

9.3 Cc loi cng trnh v h s ng x..................................................................................... 180

9.4 Phn tch kt cu ................................................................................................................. 181

9.5 Tiu ch thit k v quy nh thi cng................................................................................... 182


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9.5.1 Tng qut............................................................................................................................. 182

9.5.2 Cc yu cu b sung cho khi xy khng c ct thp tho mn Phn 1 ca tiu chun ny ............................................................................................................................ 183

9.5.3 Cc yu cu b sung cho khi xy b hn ch bin dng.................................................... 183

9.5.4 Cc yu cu b sung cho khi xy c ct thp ................................................................... 184

9.6 Kim tra an ton .................................................................................................................. 185

9.7 Cc quy nh cho nh xy n gin .................................................................................. 185

9.7.1 Tng qut............................................................................................................................. 185

9.7.2 Cc quy nh........................................................................................................................ 185

10 Cch chn y ............................................................................................................................188

10.1 Phm vi p dng.................................................................................................................. 188

10.2 Cc nh ngha..................................................................................................................... 188

10.3 Cc yu cu c bn ............................................................................................................. 190

10.4 Cc tiu ch cn tun theo ................................................................................................... 190

10.5 Cc iu khon thit k chung ............................................................................................ 190

10.5.1 Cc iu khon chung lin quan n thit b ....................................................................... 190

10.5.2 Kim sot cc chuyn ng khng mong mun.................................................................. 191

10.5.3 Kim sot cc chuyn ng nn vi sai do ng t ............................................................ 191

10.5.4 Kim sot chuyn v tng i vi nn t v cc cng trnh xung quanh .......................... 191

10.5.5 Thit k c s cng trnh c cch chn y..................................................................... 191

10.6 Tc ng ng t............................................................................................................... 192

10.7 H s ng x........................................................................................................................ 192

10.8 Cc c trng ca h cch chn ......................................................................................... 192

10.9 Phn tch kt cu ................................................................................................................. 193

10.9.1 Tng qut............................................................................................................................. 193

10.9.2 Phn tch tuyn tnh tng ng ........................................................................................ 193

10.9.3 Phn tch tuyn tnh n gin .............................................................................................. 194

10.9.4 Phn tch tuyn tnh n gin ha theo dng dao ng ...................................................... 196

10.9.5 Phn tch theo lch s thi gian ............................................................................................ 196

10.9.6 Cc b phn phi kt cu ...................................................................................................... 197

10.10 Kim tra an ton theo trng thi cc hn........................................................................ 197


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Ph lc A (tham kho) Ph phn ng chuyn v n hi.........................................................................199

Ph lc B (tham kho) Xc nh chuyn v mc tiu i vi phn tch tnh phi tuyn (y dn).............201

Ph lc C (bt buc) Thit k bn ca dm lin hp thp btng ti lin kt ...................................205

Ph lc D (tham kho) Cc thut ng v nh ngha ...............................................................................214

Ph lc E (tham kho) Cc k hiu ..........................................................................................................223

Ph lc F Mc v h s tm quan trng........................................................................................226

Ph lc G Phn cp, phn loi cng trnh xy dng ...........................................................................228

Ph lc H Bn phn vng gia tc nn lnh th vit nam...................................................................1

Ph lc I Bng phn vng gia tc nn theo a danh hnh chnh......................................................... 3

Ph lc K Bng chuyn i t nh gia tc nn sang cp ng t .....................................................25


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Li ni u

TCXDVN 375:2006: Thit k cng trnh chu ng t mc bin son trn ck 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 : Mc v h s tm quan trng

- Ph lc G : Phn cp, phn loi cng trnh xy dng

- Ph lc H : Bn phn vng gia tc nn lnh th Vit Nam

- Ph lc I : Bng Phn vng gia tc nn theo a danh hnh chnh

- Ph lc K : Bng chuyn i t nh gia tc nn sang cp ng t.

Cc tiu chun tham kho chung trch dn iu 1.2.1 chma mc 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 lmt 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 nmc. 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 mc Hi ng Khoa hc cp Nh nmc nghim

thu nm 2005. Bn s dng trong tiu chun c tin cy v php l tmkng mkng l mt phin bn c th ca bn cng tn mc chnh l theo kin ngh trong bin bn

nh gi ca Hi ng nghim thu Nh nmc.

Trong bn phn vng gia tc, nh gia tc nn tham chiu agR trn lnh th Vit Nam

mc biu th bng cc mng ng tr. Gi tr agR gia hai mng ng tr mc 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 tm quyt nh.


2

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 = JI.agR, chia thnh ba trmng hp ng t

- ng t mnh ag t 0,08g, phi tnh ton v cu to khng chn

- ng t yu 0,04g d ag < 0,08g, ch cn p dng cc gii php khng chn mc 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 cmng chn ng Ms t 5,5, ng cong ph dng 2 dng cho nhng vng c cmng 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 cmng chn ng Ms t 5,5.

Khng thit k chu ng t nhm 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 JI thch hp. Trmng hp c th c tranh chp

v mc tm quan trng, gi tr JI do ch u tm 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.


Tiu chun xy dng vit nam TCXDVN 3

3

Xut bn ln 1

Thit k cng trnh chu ng t

Design of structures for earthquake resistances

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

1. Tng qut

1.1. Phm vi p dng

1.1.1. Phm vi p dng ca tiu chun: Thit k cng trnh chu ng t

(1)P 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:

x Sinh mng con ngi c bo v;

x Cc h hng c hn ch;

x 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. Phm vi p dng ca Phn 1

(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.

(4) Chng 4 bao gm nhng quy nh thit k chung, c bit lin quan n nh.


TCXDVN 375 : 2006

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(5) 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.

x Chng 5: Nhng quy nh c th cho kt cu btng;

x Chng 6: Nhng quy nh c th cho kt cu thp;

x Chng 7: Nhng quy nh c th cho kt cu lin hp thp - btng;

x Chng 8: Nhng quy nh c th cho kt cu g;

x 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. Cc ti liu tham kho v tiu chun

(1)P 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

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


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1.2.2. Nhng Quy chun v Tiu chun tham kho khc

(1)P p dng tiu chun ny phi tham kho cc Tiu chun EN 1990, EN 1997 v EN 1999.

(2) 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 n v o lng quc t (h SI) v ng dng ca n;

EN 1090-1 Thi cng kt cu thp Phn 1: Nhng qui nh chung v nhng qui nh cho nh.

1.3. Cc gi thit

(1) 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. S phn bit gia cc nguyn tc v cc quy nh p dng

(1) Cc nguyn tc bao gm:

- 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) Cc nguyn tc c k hiu bng ch P sau con s nm trong ngoc n, v d (1)P.

(3) 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


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quan v t nht chng phi tng ng v mt an ton, kh nng s dng v bn ca kt cu.

(5) Cc quy nh p dng c k hiu bng mt con s nm trong ngoc n, v d (1).

1.5. Thut ng v nh ngha

1.5.1. Thut ng chung

(1) Nhng thut ng v nh ngha c cho trong Ph lc D;

1.5.2. Cc thut ng khc c s dng trong tiu chun

(1) Di y nh ngha mt s thut ng c s dng trong tiu chun ny:

x 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.

x 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.

x 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.

x Vng tiu tn nng lng

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.

x 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.

x H s tm quan trng

H s c lin quan n nhng hu qu ca vic h hng kt cu.

x 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.

x 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.


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x 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.

x 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.

x 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.

x Hiu ng bc 2 (hiu ng P-')

Mt cch tnh kt cu theo s tnh bin dng.

1.6. K hiu

1.6.1. Tng qut

(1) 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 Gi tr thit k ca tc ng ng t ( = JI . AEk)

AEk Gi tr c trng ca tc ng ng t i vi chu k lp tham chiu

Ed Gi tr thit k ca cc h qu tc ng

NSPT S nht p trong th nghim xuyn tiu chun (SPT)

PNCR Xc sut tham chiu vt qu trong 50 nm ca tc ng ng t tham chiu i vi yu cu khng sp

Q Tc ng thay i

S H s t nn

Se(T) Ph phn ng gia tc nn n hi theo phng nm ngang cn gi l


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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) Ph phn ng gia tc nn n hi theo phng thng ng

SDe(T) Ph phn ng chuyn v n hi

Sd(T) 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 Chu k dao ng ca h tuyn tnh mt bc t do

Ts 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 nh gia tc nn tham chiu trn nn loi A

ag Gia tc nn thit k trn nn loi A

avg Gia tc nn thit k theo phng thng ng

cu Cng chng ct khng thot nc ca t nn

dg Chuyn v nn thit k

g Gia tc trng trng

q H s ng x

vs,30 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.

JI H s tm quan trng

K H s hiu chnh cn

[ T s cn nht tnh bng phn trm

\2,i H s t hp cho gi tr c coi l lu di ca tc ng thay i i

\E,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

1.6.3. Cc k hiu khc c s dng trong chng 4

EE H qu ca tc ng ng t

EEdx, EEdy 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

D T s gia gia tc nn thit k v gia tc trng trng


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Fi Lc ng t theo phng nm ngang ti tng th i

Fa Lc ng t theo phng nm ngang tc ng ln mt b phn phi kt cu

Fb Lc ct y

H Chiu cao nh k t mng hoc t nh ca phn cng pha di

Lmax, Lmin Kch thc ln nht v kch thc nh nht trn mt bng ca ngi nh o theo cc phng vung gc

Rd Gi tr thit k ca bn

Sa H s ng t ca b phn phi kt cu

T1 Chu k dao ng c bn ca cng trnh

Ta Chu k dao ng c bn ca b phn phi kt cu

Wa Trng lng ca b phn phi kt cu

d Chuyn v

dr Chuyn v ngang thit k tng i gia cc tng

ea lch tm ngu nhin ca khi lng mt tng so vi v tr danh ngha ca n

h Chiu cao tng

mi Khi lng tng th i

n S tng pha trn mng hoc trn nh ca phn cng pha di

qa H s ng x ca b phn phi kt cu.

qd H s ng x chuyn v

si Chuyn v ca khi lng mi trong dng dao ng c bn ca cng trnh

zi Chiu cao ca khi lng mi pha trn cao trnh t tc ng ng t

Ja H s tm quan trng ca b phn phi kt cu

Jd H s vt cng cho tm cng (i-a-phc)

T H s nhy ca chuyn v ngang tng i gia cc tng.


Ac Din tch tit din ca cu kin btng

Ash Tng din tch tit din ca ct thp ai nm ngang trong nt dm-ct

Asi Tng din tch cc thanh ct thp theo tng phng cho ca dm lin kt


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Ast Din tch tit din ca ct thp ngang

Asv Tng din tch ct thp ng bng tng

Asv,i Tng din tch ca cc thanh thp ng ca ct nm gia cc thanh gc theo mt phng i qua nt

Aw Tng din tch tit din chiu ln mt nm ngang ca tng

6Asi 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

6Asj 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

6MRb 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

6MRc 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

Do ng knh ca li c ct ai hn ch bin dng trong ct tit din trn

Mi,d Mmen ti u mt ca mt dm hoc ct tnh tan kh nng chu ct thit k

MRb,i Gi tr thit k kh nng chu mmen un ca dm ti u mt th i

MRc,i Gi tr thit k ca kh nng chu mmen un ca ct ti u mt th i

NEd Lc dc trc thu c t php phn tch theo tnh hung thit k chu ng t

T1 Chu k c bn ca cng trnh theo phng ang xt

TC Chu k ng vi gii hn trn ca on c gia tc khng i ca ph n hi

VEd Lc ct trong tng thu c t php phn tch theo tnh hung thit k chu ng t

Vdd Kh nng cht ca cc thanh thp thng ng trong tng

VEd Lc ct thit k trong tng

VEd,max 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

VEd,min 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

Vfd Phn lc ma st tham gia lm tng kh nng ca tng chng li s ct do trt


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Vid Phn lc ng gp do cc thanh thp xin vo bn ca tng chng li s ct do trt

VRd, c 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

VRd, S Gi tr thit k ca kh nng chu ct chng li s trt

b Chiu rng cnh di ca dm

bc Kch thc tit din ngang ca ct

beff Chiu rng hu hiu ca cnh dm chu ko ti b mt ca ct

bi Khong cch gia cc thanh lin k nhau c gii hn bi gc un ca ct thp ai hoc bi ai mc trong ct

b0 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)

bw B dy ca phn c ct ai hn ch bin dng ca tit din tng, hoc chiu rng bng dm

bw0 B dy phn bng tng

d Chiu cao lm vic ca tit din

dbL ng knh thanh ct thp dc

dbw ng knh thanh ct thp ai

fcd Gi tr thit k ca cng chu nn ca btng

fctm Gi tr trung bnh ca cng chu ko ca btng

fyd Gi tr thit k ca gii hn chy ca thp

fyd, h Gi tr thit k ca gii hn chy ca ct thp ca bng dm theo phng nm ngang

fyd, v Gi tr thit k ca gii hn chy ca ct thp ca bng dm theo phng ng

fyld Gi tr thit k ca gii hn chy ca ct thp dc

fywd Gi tr thit k ca gii hn chy ca ct thp ngang

h Chiu cao tit din ngang

hc Chiu cao tit din ngang ca ct theo phng ang xt

hf B dy cnh

hjc Khong cch gia cc lp ngoi cng ca ct thp ct trong nt dm-ct

hjw Khong cch gia cc thanh ct thp pha trn v pha di dm


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h0 Chiu cao phn li c ct ai hn ch bin dng trong mt ct (tnh ti ng tm ca ct thp ai)

hs Chiu cao thng thy ca tng

hw Chiu cao tng hoc chiu cao tit din ngang ca dm

kD 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 H s phn nh dng ph hoi ch o trong h kt cu c tng chu lc

lc1 Chiu di thng thy ca dm hoc ct

lcr Chiu di vng ti hn

li 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

lw Chiu di tit din ngang ca tng

n Tng s cc thanh thp dc c gi bi cc thanh ct thp ai hoc ging ngang theo chu vi ca tit din ct

q0 Gi tr c bn ca h s ng x

s Khong cch ct thp ngang

xu Chiu cao ca trc trung ha

z Cnh tay n ca ni lc

D H s hiu ng hn ch bin dng, gc gia cc thanh thp t cho v trc ca dm lin kt

D0 T s kch thc ca tng trong h kt cu

D1 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

Du H s nhn ca tc ng ng t thit k theo phng nm ngang ti thi im hnh thnh c ch do ton b

Jc H s ring ca btng

JRd 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

Js H s ring ca thp

Hcu2 Bin dng ti hn ca btng khng c ct ai hn ch bin dng

Hcu2,c Bin dng ti hn ca btng c ct ai hn ch bin dng


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Hsu,k Gi tr c trng ca dn di gii hn ca ct thp

Hsy,d Gi tr thit k ca bin dng thp ti im chy do

K 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

Pf H s ma st gia btng vi btng khi chu tc ng c chu k

PI H s do kt cu khi un

PG H s do kt cu khi chuyn v

v Lc dc quy i trong tnh hung thit k chu ng t

[ Chiu cao quy i tnh n trc trung ha

U Hm lng ct thp chu ko

U Hm lng ct thp chu nn trong dm

Vcm Gi tr trung bnh ca ng sut php ca btng

Uh Hm lng ct thp ca cc thanh nm ngang ca phn bng tng

U1 Tng hm lng ct thp dc

Umax Hm lng ct thp chu ko cho php ti a trong vng ti hn ca dm khng chn chnh

Uv Hm lng ct thp ca cc thanh thng ng ca phn bng tng

Uw Hm lng ct thp chu ct

Zv T s c hc ca ct thp thng ng trong bn bng

Zwd T s th tch c hc ca ct ai hn ch bin dng trong pham vi cc vng ti hn


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L Nhp dm

MEd Mmen un thit k tnh ton theo tnh hung thit k chu ng t

Mp1,RdA Gi tr thit k ca mmen do ti u mt A ca mt cu kin

Mp1,RdB Gi tr thit k ca mmen do ti u mt B ca mt cu kin

NEd Lc dc thit k tnh ton theo tnh hung thit k chu ng t

NEd,E Lc dc t php tnh ton ch do tc ng ng t thit k

NEd,G 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

Np1,Rd Gi tr thit k ca bn do khi ko ca tit din ngang ca mt cu kin theo EN 1993-1-1:2004

NRd

(MEd,VEd)

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

Rd bn ca lin kt theo EN 1993-1-1:2004

Rfy 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

VEd Lc ct thit k tnh ton theo tnh hung thit k chu ng t

VEd,G 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

VEd,M Lc ct do cc mmen do t vo ti hai u dm

Vwp,Ed Lc ct thit k trong mt ca bn bng panen do tc ng ng t thit k gy ra

Vwp,Rd bn ct thit k ca bn bng panen theo EN 1993-1-1:2004

e Chiu di ca on ni khng chn

fy Gii hn chy danh ngha ca thp

fymax ng sut chy cho php ti a ca thp

q H s ng x

tw B dy bn bng ca on ni khng chn

tf B dy bn cnh ca on ni khng chn

: 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


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lng trong cc khung ging ng tm hoc lch tm tng ng vi iu (1) trong C1.6.7.4 v 6.8.3.


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D 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

D1 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

Du 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

JM H s ring cho tham s vt liu

Jov H s vt cng ca vt liu

G vng ca dm ti gia nhp so vi ng tip tuyn vi trc dm ti u dm (Hnh 6.11)

Jpb 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

Js H s ring ca thp

Tp Kh nng xoay ca vng khp do

O mnh khng th nguyn ca mt cu kin nh nh ngha trong EN 1993-1-1:2004


Apl Din tch ca tm theo phng nm ngang

Ea Mun n hi ca thp

Ecm Mun n hi trung bnh ca btng theo EN 1992-1-1:2004

Ia Mmen qun tnh ca din tch phn thp trong tit din lin hp, i vi trc i qua tm ca tit din lin hp

Ic Mmen qun tnh ca din tch phn btng trong tit din lin hp, i vi trc i qua tm ca tit din lin hp

Ieq Mmen qun tnh tng ng ca din tch tit din lin hp

Is 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

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


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Vwp,Ed 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

Vwp,Rd bn ct ca bn bng bng lin hp thp - btng theo EN 1994-1:2004

b Chiu rng ca bn cnh

be Chiu rng tnh ton bn cnh v mi pha ca bn bng bng thp

beff Tng chiu rng hu hiu ca bn cnh bng btng

b0 Chiu rng (kch thc nh nht) ca li btng b hn ch bin dng

dbL ng knh ct thp dc

dbw ng knh ct thp ai

fyd Gii hn chy thit k ca thp

fydf Gii hn chy thit k ca thp trong bn cnh

fydw Cng thit k ca ct thp bn bng

hb Chiu cao ca dm lin hp

bb Chiu rng ca dm lin hp

hc Chiu cao ca tit din ct lin hp thp - btng

kr H s hu hiu ca hnh dng cc sn ca mt ct tm thp

kt H s suy gim bn ct thit k ca cc nt lin kt theo EN 1994-1

lcl Chiu di thng thy ca ct

lcr Chiu di ca vng ti hn

n T s mun thp - btng i vi tc ng ngn hn

q H s ng x

r H s gim cng btng tnh ton cng ca ct lin hp thp - btng

tf B dy bn cnh

Jc H s ring ca btng


Jov H s vt cng ca vt liu

Js H s ring ca thp


TCXDVN 375 : 2006

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Ha Tng bin dng ca thp ti trng thi cc hn

Hcu2 Bin dng nn cc hn ca btng khng b hn ch bin dng

K lin kt ti thiu nh nh ngha trong 6.6.1.2 ca EN 1994-1-1:2004


E0 Mun n hi ca g khi cht ti tc thi

b Chiu rng ca tit din g

d ng knh vt lin kt

h Chiu cao ca dm g

kmod H s iu chnh cng ca g cho cht ti tc thi theo EN 1995-1-1:2004

q H s ng x



ag,urm 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

Amin 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

fb, min Cng nn tiu chun ca vin xy vung gc vi mt y

fbh, min Cng nn tiu chun ca vin xy song song vi mt y v trong mt phng tng

fm, min Cng ti thiu cho va xy

h Chiu cao thng thy ln nht ca l m lin k vi bc tng

hef Chiu cao hu hiu ca tng

l Chiu di ca tng

n S tng nm pha trn mt t

pA,min 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

pmax T l phn trm ca tng din tch sn bn trn mc ang xt

q H s ng x

tef B dy hu hiu ca tng


TCXDVN 375 : 2006

19

'A,max 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

'm,max chnh lch ln nht v khi lng gia cc tng lin k nhau ca nh xy n gin


Js H s ring ca ct thp

Omin T s gia kch thc ca cnh ngn v cnh di trong mt bng


Keff 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

KV cng tng cng ca h cch chn theo phng thng ng

Kxi cng hu hiu ca b cch chn th i theo phng x

Kyi cng hu hiu ca b cch chn th i theo phng y

Teff 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

Tf Chu k c bn ca kt cu bn trn c gi thit l ngm ti y

TV Chu k c bn ca kt cu bn trn theo phng thng ng, kt cu bn trn c xem l tuyt i cng

M Khi lng ca kt cu bn trn

Ms mnh

ddc Chuyn v thit k hu hiu ca tm cng theo phng xem xt

ddb Tng chuyn v thit k ca b cch chn

etot,y Tng lch tm theo phng y

fj Lc theo phng ngang ti mi tng th j

ry Bn knh xon ca h cch chn

(xi,yi) Ta ca b cch chn th i so vi tm cng hu hiu

Gi H s khuch i

[eff cn hu hiu

1.7. n v SI

(1)P Cc n v SI phi c s dng ph hp vi ISO 1000.


TCXDVN 375 : 2006

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(2) Khi tnh ton dng cc n v sau y:

- Lc v ti trng: kN, kN/m, kN/m2

- Khi lng ring: kg/m3, t/m3

- Khi lng: kg, t

- Trng lng ring: kN/m3

- ng sut v cng :

N/mm2 (= MN/m2 hoc MPa), kN/m2 (=kPa)

- Mmen (un,v.v..): kNm

- Gia tc: m/s2, g (g=9,81m/s2)


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2. Yu cu v tnh nng v cc tiu ch cn tun theo

2.1. Nhng yu cu c bn

(1)P 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:

x 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 JI (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 PNCR hoc cho TNCR s dng cho Vit Nam l PNCR =10% vTNCR = 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.

x 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 JI. 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 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


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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) a 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 JI, 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: JI | (TLR/ TL)

-1/k. Mt cch

khc, gi tr ca h s tm quan trng JI, 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: JI | (PL/ PLR)

-1/k.

2.2. Cc tiu ch cn tun theo

2.2.1. Tng qut

(1)P 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):

x Cc trng thi cc hn

x 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.

(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


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cc yu cu c bn ca tiu chun ny m khng cn kim tra phn tch an ton.

2.2.2. Trng thi cc hn

(1)P 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.

2.2.3. Trng thi hn ch h hng

(1)P 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.


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(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.

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.


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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. iu kin nn t v tc ng ng t

3.1. iu kin nn t

3.1.1. Tng qut

(1)P Phi thc hin cng tc kho st ph hp phn bit iu kin nn t theo 3.1.2.

(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. Nhn dng cc loi nn t

(1) 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

Cc tham s

Loi M t vs,30(m/s)

NSPT

(nht/30cm)

cu

(Pa)

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.

!800 - -

B 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.

360-800 !50 !250

C t ct, cui si cht, cht va hoc t st cng c b dy ln t hng chc ti hng trm mt.

180-360 15-50 70 -


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Cc tham s

Loi M t vs,30(m/s)

NSPT

(nht/30cm)

cu

(Pa)

250

D 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.

180 15 70

E 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.

S1 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.

100

(tham kho)

- 10-20

S2 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.

(2) Nn t cn c phn loi theo gi tr ca vn tc sng ct trung bnh vs,30(m/s) nu c gi tr ny. Nu khng, c th dng gi tr NSPT.

(3) Vn tc sng ct trung bnh, vs,30 c tnh ton theo biu thc sau:

N

i i

is h

1

30,

30

Q

Q

(3.1)

trong :

hi, vi chiu dy (m) v vn tc sng ct (ti mc bin dng ct bng 10-5 hoc

thp hn) ca lp th i trong tng s N lp tn ti trong 30m t trn b mt.

(4)P i vi cc a im c iu kin nn t thuc mt trong hai loi nn c bit S1 v S2 cn phi c nghin cu c bit xc nh tc ng ng t. i vi nhng loi nn ny, c bit l i vi nn S2, cn phi xem xt kh nng ph hu nn khi chu tc ng ng t.

Ghi ch: Cn c bit lu nu trm tch l nn loi S1. in hnh ca loi nn t ny l gi tr vs rt thp, cn bn trong nh v phm vi m rng bt thng v ng x tuyn tnh. V th, c th to ra nhng hiu ng d thng v s khuch i chn ng nn v tng tc nn-cng trnh (xem chng 6, Phn 2). Trng hp ny, cn nghin cu c bit xc nh tc ng ng t nhm thit lp quan h gia ph phn ng vi chiu dy v gi tr vs ca lp st/ bn v s tng phn v cng gia lp ny v cc lp t nm di.


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3.2. Tc ng ng t

3.2.1. Cc vng ng t

(1)P Vi hu ht nhng ng dng ca tiu chun ny, nguy c ng t c m t di dng mt tham s l nh gia tc nn tham chiu agR trn nn loi A. Cc tham s b sung cn thit cho cc dng kt cu c th c cho trong cc phn lin quan ca tiu chun ny.

Ghi ch: nh gia tc nn tham chiu agR trn nn loi A c ly t bn phn vng gia tc nn lnh th Vit Nam cho trong Ph lc H, Phn 1 hoc c ly t bn phn vng nh ng t ca mt s vng lnh th c c quan c thm quyn ph duyt.

(2) Trong tiu chun ny, 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. T nh gia tc nn c th chuyn i sang cp ng t theo thang MSK-64 hoc thang MM da vo bng chuyn i cho trong Ph lc K, Phn 1.

(3) nh gia tc nn tham chiu do c quan Nh nc c thm quyn la chn cho tng vng ng t, tng ng vi chu k lp tham chiu TNCR ca tc ng ng t i vi yu cu khng sp (hoc mt cch tng ng l xc sut tham chiu vt qu trong 50 nm, PNCR) (xem 2.1(1)P). H s tm quan trng JI bng 1,0 c gn cho chu k lp tham chiu. Vi chu k lp khc chu k lp tham chiu (xem cc mc quan trng trong 2.1(3)P v (4)), gia tc nn thit k ag trn nn loi A s bng agR nhn vi h s tm quan trng JI (tc l ag = JI. agR) (xem ghi ch

ca 2.1(4)).

Gi tr agR ly theo Bn phn vng gia tc nn lnh th Vit Nam, t l 1 :1 000 000 (phin bn thu nh cho trong Ph lc H, Phn 1) hoc Bng phn vng gia tc nn theo a danh hnh chnh cho trong Ph lc I, Phn 1 (gi tr gia tc nn agR cho trong bng c xem l gi tr i din cho c vng a danh).

(4) Trng hp ng t yu, c th s dng cc quy trnh thit k chu ng t c gim nh hoc n gin ho cho mt s loi, dng kt cu.

Ghi ch: Trng hp ng t yu l trng hp khi gia tc nn thit k ag trn nn loi A khng vt qu 0,08g (0,78m/s2).

(5)P Trong trng hp ng t rt yu, khng cn phi tun theo nhng iu khon ca tiu chun ny.

Ghi ch: Trng hp ng t rt yu l trng hp khi gia tc nn thit k ag trn nn loi A khng vt qu 0,04g (0,39m/s2).

3.2.2. Biu din c bn ca tc ng ng t

3.2.2.1. Tng qut

(1)P Trong phm vi tiu chun ny, chuyn ng ng t ti mt im cho trc trn b mt c biu din bng ph phn ng gia tc n hi, c gi tt l ph phn ng n hi.


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(2) Dng ca ph phn ng n hi c ly nh nhau i vi hai mc tc ng ng t gii thiu trong 2.1(1)P v 2.2.1(1)P vi yu cu khng sp (trng thi cc hn - tc ng ng t thit k) v i vi yu cu hn ch h hng.

(3)P Tc ng ng t theo phng nm ngang c m t bng hai thnh phn vung gc c xem l c lp v biu din bng cng mt ph phn ng.

(4) i vi ba thnh phn ca tc ng ng t, c th chp nhn mt hoc nhiu dng khc nhau ca ph phn ng, ph thuc vo cc vng ngun v ln ng t pht sinh t chng.

Ghi ch 1: Khi la chn hnh dng ph hp cho ph phn ng, cn lu ti ln ca nhng trn ng t gp phn ln nht trong vic nh gi nguy c ng t theo phng php xc sut m khng thin v gii hn trn an ton (v d trn ng t cc i c th xy ra) c xc nh nhm mc ch ny.

(5) nhng ni chu nh hng ng t pht sinh t cc ngun rt khc nhau, kh nng s dng nhiu hn mt dng ph phn ng phi c xem xt c th th hin ng tc ng ng t thit k. Trong nhng trng hp nh vy, thng thng gi tr ca ag cho tng loi ph phn ng v tng trn ng t s khc nhau.

(6) i vi cc cng trnh quan trng (JI !1) cn xt cc hiu ng khuch i a hnh.

Ghi ch: Ph lc tham kho A, Phn 2 cung cp thng tin v hiu ng khuch i a hnh.

(7) C th biu din chuyn ng ng t theo hm ca thi gian (xem 3.2.3).

(8) i vi mt s loi cng trnh, c th xt s bin thin ca chuyn ng nn t trong khng gian cng nh theo thi gian.

3.2.2.2. Ph phn ng n hi theo phng nm ngang

(1)P Vi cc thnh phn nm ngang ca tc ng ng t, ph phn ng n hi Se(T) c xc nh bng cc cng thc sau (xem Hnh 3.1):

0 : ( ) . . 1 .( .2,5 1)B e g

B

TT T S T a S

TK

d d

(3.2)

: ( ) . . .2,5B C e gT T T S T a SKd d (3.3)

dd

TTSaTSTTT CgeDC 5,2: K

(3.4)

dd

2

.5,2:4

TTTSaTSsTT DCgeD K

(3.5)

trong :

Se(T) Ph phn ng n hi ;


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T Chu k dao ng ca h tuyn tnh mt bc t do;

ag Gia tc nn thit k trn nn loi A (ag = JI. agR);

TB Gii hn di ca chu k, ng vi on nm ngang ca ph phn ng gia tc;

TC Gii hn trn ca chu k, ng vi on nm ngang ca ph phn ng gia tc;

TD Gi tr xc nh im bt u ca phn phn ng dch chuyn khng i trong ph phn ng;

S H s nn;

K H s iu chnh cn vi gi tr tham chiu K = 1 i vi cn nht 5%,

xem (3) ca iu ny.

Hnh 3.1. Dng ca ph phn ng n hi.

(2)P Gi tr ca chu k TB, TC v TD v ca h s nn S m t dng ph phn ng n hi ph thuc vo loi nn t, nu khng xt ti a cht tng su (xem 3.1.2(1)).

Ghi ch 1: i vi 5 loi nn t A, B, C, D, v E, gi tr cc tham s S, TB, TC v TD c cho trong Bng 3.2, cc dng ph c chun ho theo ag vi cn 5% c cho Hnh 3.2.

Bng 3.2. Gi tr ca cc tham s m t cc ph phn ng n hi

Loi nn t S TB(s) TC(s) TD(s)

A 1,0 0,15 0,4 2,0

B 1,2 0,15 0,5 2,0

C 1,15 0,20 0,6 2,0


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D 1,35 0,20 0,8 2,0

E 1,4 0,15 0,5 2,0

Hnh 3.2. Ph phn ng n hi cho cc loi nn t t A n E ( cn 5%).

Ghi ch 2: i vi cc nn t Loi S1 v S2, cn c cc nghin cu ring xc nh cc gi tr tng ng ca S, TB, TC v TD.

(3) H s iu chnh cn K c th xc nh bng biu thc:

K= 10/(5+ [ ) t 0,55 (3.6)

trong :

[ t s cn nht ca kt cu, tnh bng phn trm.

(4) Trng hp c bit, khi dng t s cn nht khc 5%, gi tr ny c cho trong phn c lin quan ca tiu chun ny.

(5)P Ph phn ng chuyn v n hi SDe(T), nhn c bng cch bin i trc tip ph phn ng gia tc n hi Se(T) theo biu thc sau:

2

.2)()(

STTSTS eDe

(3.7)

(6) Thng thng, cn p dng biu thc (3.7) cho cc chu k dao ng khng vt qu 4,0s. i vi cc kt cu c chu k dao ng ln hn 4,0s c th dng mt nh ngha ph chuyn v n hi hon chnh hn.

Ghi ch: Vi ph phn ng n hi tham kho ghi ch 1 ca 3.2.2.2(2)P, mt nh ngha nh th c trnh by trong Ph lc tham kho A di dng ph phn ng chuyn v. i vi nhng chu k di hn 4s, ph phn ng gia tc n hi Se(T) c th ly t ph phn ng chuyn v n hi da vo biu thc (3.7).


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3.2.2.3. Ph phn ng n hi theo phng thng ng

(1)P Thnh phn thng ng ca tc ng ng t phi c th hin bng ph phn ng n hi, Sve(T), c xc nh bng cch s dng cc biu thc t (3.8) n (3.11).

dd )10,3.(1.:0 K

BvgveB T

TaTSTT

(3.8)

0,3..: KvgveCB aTSTTT dd (3.9)

TT

aTSTTT CvgveDC .0,3..: K dd (3.10)

2

..0,3..:4

TTT

aTSsTT DCvgveD K dd (3.11)

Ghi ch: i vi 5 loi nn t A, B, C, D, v E, gi tr cc tham s TB, TC v TD m t cc ph thng ng c cho trong Bng 3.3. Khng p dng cc gi tr ny cho cc loi nn t c bit S1 v S2.

Bng 3.3. Gi tr cc tham s m t ph phn ng n hi theo phng thng ng

gvg aa / TB(s) TC(s) TD(s)

0,90 0,05 0,15 1,0

3.2.2.4. Chuyn v nn thit k

(1) Tr phi c nghin cu ring da trn thng tin sn c, gi tr chuyn v nn thit k dg ng vi gia tc nn thit k c th tnh bng biu thc sau:

dg = 0,025. ag . S. TC .TD (3.12)

vi ag, S, TC v TD nh nh ngha trong 3.2.2.2.

3.2.2.5. Ph thit k dng cho phn tch n hi

(1) Kh nng khng chn ca h kt cu trong min ng x phi tuyn thng cho php thit k kt cu vi cc lc ng t b hn so vi cc lc ng vi phn ng n hi tuyn tnh.

(2) trnh phi phn tch trc tip cc kt cu khng n hi, ngi ta k n kh nng tiu tn nng lng ch yu thng qua ng x do ca cc cu kin ca n v/hoc cc c cu khc bng cch phn tch n hi da trn ph phn ng c chit gim t ph phn ng n hi, v th ph ny c gi l ph thit k. S chit gim c thc hin bng cch a vo h s ng x q.

(3)P H s ng x q biu th mt cch gn ng t s gia lc ng t m kt cu s phi chu nu phn ng ca n l hon ton n hi vi t s cn nht 5% v lc ng t c th s dng khi thit k theo m hnh phn tch n hi thng thng m vn tip tc bo m cho kt cu mt phn ng tha mn cc yu cu t ra. Gi tr ca h s ng x q trong c xt ti nh hng ca t s cn nht khc 5%


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ca cc loi vt liu v h kt cu khc nhau ty theo cp do kt cu tng ng c cho trong cc phn khc nhau ca tiu chun ny. Gi tr ca h s ng x q c th khc nhau theo cc hng nm ngang khc nhau ca kt cu, mc d s phn loi cp do kt cu phi nh nhau trong mi hng.

(4)P i vi cc thnh phn nm ngang ca tc ng ng t, ph thit k Sd(T) c xc nh bng cc biu thc sau:

2 2,5 20 : ( ) . .

3 3B d g

B

TT T S T a S

T q

d d

(3.13)

2,5: ( ) . .B C d gT T T S T a S

qd d

(3.14)

t

dd

g

Cg

dDC

a

TT

qSa

TSTTT.

5,2.

:

E (3.15)

t

d

g

DCg

dD

a

TTT

qSa

TSTT.

.5,2.

: 2

E (3.16)

Trong :

ag, S, TC v TD nh nh ngha trong 3.2.2.2;

Sd(T) ph thit k;

q h s ng x;

E h s ng vi cn di ca ph thit k theo phng nm ngang, E= 0,2.

(5) i vi thnh phn thng ng ca tc ng ng t, ph thit k cho bi cc biu thc (3.13) n (3.16) vi gia tc nn thit k avg theo phng thng ng c thay bng gi tr ag ; S ly bng 1,0 cn cc tham s khc nh nh ngha trong 3.2.2.3.

(6) i vi thnh phn thng ng ca tc ng ng t, h s ng x q ni chung c th ly nh hn hoc bng 1,5 cho mi loi vt liu v h kt cu.

(7) Vic ly gi tr q ln hn 1,5 theo phng thng ng cn c l gii thng qua phn tch ph hp.

(8)P Ph thit k c xc nh nh trn khng thch hp cho thit k cng trnh c h cch chn y hoc c h tiu tn nng lng.

3.2.3. Nhng cch biu din khc ca tc ng ng t

3.2.3.1. Biu din theo lch s thi gian

3.2.3.1.1. Tng qut


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(1)P Chuyn ng ng t cng c th c biu din di dng gin gia tc nn v cc i lng lin quan (vn tc v chuyn v).

(2)P Khi tnh ton kt cu theo m hnh khng gian, chuyn ng ng t phi bao gm ba gin gia tc tc ng ng thi. Khng th s dng ng thi cng mt gin gia tc cho c hai phng nm ngang. C th thc hin nhng n gin ho ph hp vi nhng phn c lin quan ca tiu chun ny.

(3) Ty theo tnh cht ca vic p dng v thng tin thc c, vic m t chuyn ng ng t c th thc hin bng cch s dng cc gin gia tc nhn to (xem 3.2.3.1.2) v cc gin gia tc ghi c hoc cc gin gia tc m phng (xem 3.2.3.1.3).

3.2.3.1.2. Gin gia tc nhn to

(1)P Cc gin gia tc nhn to phi thit lp ph hp vi ph phn ng n hi cho trong 3.2.2.2 v 3.2.2.3 vi t s cn nht 5% ( [= 5%).

(2)P Khong thi gian ko di ca cc gin gia tc phi ph hp vi mnh v cc c trng c lin quan khc ca hin tng ng t dng lm c s xc nh ag.

(3) Khi khng c d liu hin trng c th, khong thi gian ko di ti thiu Ts ca phn dng trong cc gin gia tc c ly bng 10s.

(4) B gin gia tc nhn to cn tun th nhng quy nh sau y:

a) Ti thiu cn s dng ba gin gia tc;

b) Cc gi tr trung bnh ca ph phn ng gia tc khi T=0 (c tnh t cc gin gia tc) khng nh hn gi tr ag.S ca a im ang xt.

c) Trong min chu k t 0,2T1 n 2T1, trong T1 l chu k c bn ca kt cu theo phng gin gia tc c p dng, bt k gi tr no ca ph phn ng n hi trung bnh ng vi t s cn 5% tnh c t tt c cc khong thi gian khng c nh hn 90% gi tr ng vi ph phn ng n hi c t s cn 5%.

3.2.3.1.3. Gin gia tc ghi c hoc gin gia tc m phng

(1)P C th s dng gin gia tc ghi c hoc gin gia tc thit lp thng qua m phng vt l ngun pht sinh v cc c ch lan truyn min l cc mu s dng c nh gi l tng thch vi cc c trng ng t ca ngun pht sinh v cc iu kin nn t ph hp vi a im xy dng. Cc gi tr ca gin gia tc ny c hiu chnh theo gi tr ag.S ca vng ang xt.

(2)P Vic phn tch hiu ng khuch i nn t v vic kim tra n nh ng lc mi dc, cn xem 2.2, Phn 2.

(3) B gin gia tc ghi c hoc m phng c s dng cn tun theo 3.2.3.1.2(4).


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3.2.3.2. M hnh khng gian ca tc ng ng t

(1)P i vi kt cu c nhng c trng ring n mc khng th gi thit rng lc kch ng tt c cc im ta l nh nhau, phi s dng cc m hnh khng gian cho tc ng ng t (xem 3.2.2.1(8)).

(2)P Cc m hnh khng gian ni trn phi ph hp vi cc ph phn ng n hi c s dng nh ngha tc ng ng t theo 3.2.2.2 v 3.2.2.3.

3.2.4. Cc t hp tc ng ng t vi cc tc ng khc

(1)P Gi tr thit k Ed ca cc h qu tc ng do ng t gy ra phi c xc nh

theo cng thc: , 2, ,

1 1

" " " " " "dd k j E i k i

j i

E G P A Qt t

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