Kingpost Design

THIET KE THIET KE THIET KE THIET KE KINGPOSTKINGPOSTKINGPOSTKINGPOST & & & & SHEAR STUDSHEAR STUDSHEAR STUDSHEAR STUD

TO GI VIT_2010 KETCAU.COM Page 1

THIET KE CAC KETTHIET KE CAC KETTHIET KE CAC KETTHIET KE CAC KET CAU PHUC VU CHO TCAU PHUC VU CHO TCAU PHUC VU CHO TCAU PHUC VU CHO THI CONG TANG HAM HI CONG TANG HAM HI CONG TANG HAM HI CONG TANG HAM THEO THEO THEO THEO PHNG PHAP TOPDOWNPHNG PHAP TOPDOWNPHNG PHAP TOPDOWNPHNG PHAP TOPDOWN

5.1. THIET KE COT CHOTHIET KE COT CHOTHIET KE COT CHOTHIET KE COT CHO NG TAM KINGPOSTNG TAM KINGPOSTNG TAM KINGPOSTNG TAM KINGPOST 5.1.1. KHAI BAO MO HNHKHAI BAO MO HNHKHAI BAO MO HNHKHAI BAO MO HNH

Cot chong tam chu yeu chu tai trong thang ng cua cac tang ham va mot vai tang noi trong giai oan thi cong tang ham. Gan ung nhat, sinh vien chon mo hnh tnh toan noi lc cho cot chong tam vao giai oan thi cong ao at en cao trnh chuan b thi cong san tang ham 3.

Gia thuyet rang khi thi cong xuong tang ham 3, th ben tren a thi cong c 5 tang noi. Khi o mo hnh tnh toan noi lc cho cot chong tam la 3 tang ham va 5 tang noi.

Hnh.5.1. Mo hnh tnh toan cot chong tam



5.1.2. KHAI BAO VAT LIEUKHAI BAO VAT LIEUKHAI BAO VAT LIEUKHAI BAO VAT LIEU

Be tong cap o ben B30, co Rn = 17MPa, Rtn = 1.2MPa.

Cot thep AIII, co Rs = Rsc = 365MPa.

Vat lieu lam cot chong tam: cot chong tam co tiet dien ch I to hp t nhng tam thep ban co chieu day t 20mm, vi cac ch tieu cng o nh sau :

Mac thepMac thepMac thepMac thep E( kN/mE( kN/mE( kN/mE( kN/m 2222)))) FFFF uuuu ( kN/m( kN/m( kN/m( kN/m 2222)))) FFFF yyyy (kN/m(kN/m(kN/m(kN/m 2222)))) F (kN/mF (kN/mF (kN/mF (kN/m 2222)))) CCT38 2.1x108 380000 230000 220000

5.1.3. KHAI BAO CAC TIET DIENKHAI BAO CAC TIET DIENKHAI BAO CAC TIET DIENKHAI BAO CAC TIET DIEN

5.1.3.1. San :San :San :San :

San tang tret, san tang ham 1 va san tang ham 2 : toan bo cac o san eu co chieu day 300mm.

Cac san tang noi co chieu day 150mm.

5.1.3.2. Dam: Dam: Dam: Dam:

Cac dam chnh 300x700mm, dam bien cung co co kch thc 300x700m m.

Dam tai v tr loi thang phuc vu thi cong topdown phan loi thang: co tiet dien 60x120cm va 50x80cm

5.1.3.3. Cot chong tam (kingpost)Cot chong tam (kingpost)Cot chong tam (kingpost)Cot chong tam (kingpost)

Hnh.5.2. Mo hnh bo tr cot chong tam



Hnh.5.3. Mat bang bo tr cot chong tam TTTTTTTT V trV trV trV tr Ten cotTen cotTen cotTen cot Tiet dien (mm)Tiet dien (mm)Tiet dien (mm)Tiet dien (mm)

1 Cot goc C1, C19, C14, C18 400X600

2 Cot bien C40, C43, C45, C12, C44, C15, C17, C9, C34

500X640

3 Cot gia C32, C33, C8, C20, C26 500X640

4 Cot loi thang

C42, C49, C53, C54, C41, C47 400X400

5.1.3.4. Tng vay : Tng vay : Tng vay : Tng vay :

Co chieu day 1.2m, chieu sau thc te cua tng vay la -53m, nhng trong mo hnh tnh toan nay, sinh vien khai bao tng vay ngam tai v tr cao trnh ay san tang ham 3 va co o cng khang uon theo 2 phng bang 0.

5.1.3.5. VacVacVacVac h chu lc va loi thang mayh chu lc va loi thang mayh chu lc va loi thang mayh chu lc va loi thang may: tat ca co chieu day 300mm.



5.1.4. TAI TRONGTAI TRONGTAI TRONGTAI TRONG

5.1.4.1. Hoat tai thi congHoat tai thi congHoat tai thi congHoat tai thi cong

San tret: tap trung nhieu thiet b, vat t thi cong, nen co the lay Ptret = 20 kN/m2.

San tang ham 1 va san tang ham 2 : Pham1 = Pham2 = 6 kN/m2.



San tang noi : Pnoi = 6 kN/m2.

5.1.4.1. Noi lc trong cac san tanNoi lc trong cac san tanNoi lc trong cac san tanNoi lc trong cac san tan g ham do ap lc at gay rag ham do ap lc at gay rag ham do ap lc at gay rag ham do ap lc at gay ra

Tai trong nay lay t mo hnh tnh toan tng vay trong giai oan ao at thi cong tang ham 3, c nhap theo chu vi cua tng san di dang phan bo eu tren ng thang.

Tang tret : Ntret = 433.6 kN/m



Tang ham 1 : Nham1 = - 645.9 kN/m

Tang ham 2 : Nham2 = - 950 kN/m



5.1.5. KIEM TRA TIET DIEN COT CHONG TAM KIEM TRA TIET DIEN COT CHONG TAM KIEM TRA TIET DIEN COT CHONG TAM KIEM TRA TIET DIEN COT CHONG TAM

T ket qua chay mo hnh trong ETABS. ta co ket qua noi lc cho he cot chong tam nh sau:

Hnh.5.4. Ket qua lc doc trong he cot chong tam

Hnh.5.5. Ket qua mo men M33 trong he cot chong tam



Hnh.5.1. Ket qua mo men M22 trong he cot chong tam e tnh toan kiem tra he cot chong tam, ta dung 3 cap noi lc nh sau:

Cap th 1 (Nmax, MXtu, MYtu)

Cap th 2 (MXmax, MYtu, Ntu)

Cap th 3 (MYmax, MXtu, Ntu)

Ta tm 3 cap to hp noi lc cho moi nhom cot, ket qua to hp noi lc nh sau:

TTTTTTTT V trV trV trV tr Tiet dien Tiet dien Tiet dien Tiet dien

(mm)(mm)(mm)(mm) Cap noi lcCap noi lcCap noi lcCap noi lc

Lc doc N Lc doc N Lc doc N Lc doc N (kN)(kN)(kN)(kN)

Moment Moment Moment Moment Mx (kNm)Mx (kNm)Mx (kNm)Mx (kNm)

Moment Moment Moment Moment My (kNm)My (kNm)My (kNm)My (kNm)

1 Cot goc 400X600 Cap th 1 3333 4444 65656565 0.57 1.35 Cap th 2 2574 17.8317.8317.8317.83 0.95 Cap th 3 2836 3.81 10.2410.2410.2410.24

2 Cot bien 500X640 Cap th 1 5555 029029029029 18.62 12.36 Cap th 2 4289 100.56100.56100.56100.56 10.07 Cap th 3 4538 14.56 85.6785.6785.6785.67

3 Cot gia 500X640 Cap th 1 6666 314314314314 2.63 1.62 Cap th 2 4137 27.3627.3627.3627.36 2.04 Cap th 3 5024 7.14 31.0231.0231.0231.02

4 Cot loi thang

400X600 Cap th 1 3386338633863386 5.23 1.00 Cap th 2 3254 21.5621.5621.5621.56 0.87



Cap th 3 2897 4.62 15.6215.6215.6215.62

e cho an toan nhat, sinh vien chon cach kiem tra nh sau: oi vi tng loai tiet dien cot, chon ra Nmax cua cap noi lc th nhat, MXmax cua cap noi lc th 2, MYmax cua cap noi lc th 3 e kiem tra tiet dien cot chong tam. Ket qua tnh toan nh sau

TTTTTTTT V trV trV trV tr Tiet dien (mm)Tiet dien (mm)Tiet dien (mm)Tiet dien (mm) Lc doc Lc doc Lc doc Lc doc

N (kN)N (kN)N (kN)N (kN) Moment Moment Moment Moment

Mx (kNm)Mx (kNm)Mx (kNm)Mx (kNm) Moment Moment Moment Moment

MMMM y (kNm)y (kNm)y (kNm)y (kNm)

1 Cot goc va Cot loi thang

Ch I to hp 400x600x30x30

3465 21.56 15.62

2 Cot bien va Cot gia

Hnh hop 500x640x30x30

6314 100.56 85.67

Kiem tra cot chong tam co tiet dien hnh hop 500x600x50x40mmKiem tra cot chong tam co tiet dien hnh hop 500x600x50x40mmKiem tra cot chong tam co tiet dien hnh hop 500x600x50x40mmKiem tra cot chong tam co tiet dien hnh hop 500x600x50x40mm (kingpost loai(kingpost loai(kingpost loai(kingpost loai 1)1)1)1)

V trV trV trV tr Tiet dien (mm)Tiet dien (mm)Tiet dien (mm)Tiet dien (mm) Lc doc Lc doc Lc doc Lc doc



My (kNm)My (kNm)My (kNm)My (kNm) Cot bien va Cot gia

Hnh hop 500x600x30x30

6314 100.56 85.67

a. Xac nh chieu dai tnh toana. Xac nh chieu dai tnh toana. Xac nh chieu dai tnh toana. Xac nh chieu dai tnh toan

Chieu dai tnh toan trong mat phang khung lx = 0.7x6 = 4.2m

Chieu dai tnh toan ngoai mat phang khung ly = 4.2m

b. Xac nh o lech tam va tiet dien cotb. Xac nh o lech tam va tiet dien cotb. Xac nh o lech tam va tiet dien cotb. Xac nh o lech tam va tiet dien cot

o lech tam:

Hnh.5.2.

X0X X 0

Y0Y Y 0

M 100.56e 100 1.11cm e e e' 1.11 5 6.11cm

N 6314M 85.67

e 100 0.91cm e e e' 0.91 5 5.91cmN 6314

= = = = + = + =

= = = = + = + =

Vi e = 5cm la o lech tam cho phep khi thi cong cot chong tam.

Chon tiet dien cot chong tam co cac kch thc nh sau :



Hnh.5.3. Tiet dien cot chong tam loai 1 c. Cac dat trng tiet dienc. Cac dat trng tiet dienc. Cac dat trng tiet dienc. Cac dat trng tiet dien

A (cm2)

IX (cm4)

IY (cm4)

WX (cm3)

WY (cm3)

rX (cm)

rY (cm)

X (cm)

Y (cm)

932 106018 104455 3927 4178 10.67 10.59 39.38 39.67

Ta co XXXX va YYYY eu nho hn o manh gii han [] = 120] = 120] = 120] = 120

x x 8f 345000

=39.38 =1.52E 2.110

=

y y 8f 345000

=39.67 =1.55E 2.110

=

d. o lech tam tng oi m va o ld. o lech tam tng oi m va o ld. o lech tam tng oi m va o ld. o lech tam tng oi m va o l ech tam tnh oi mech tam tnh oi mech tam tnh oi mech tam tnh oi m eeee

xx

x

e A 6.11 932m 1.44

W 3927

= = =

YY

Y

e A 5.91 932m 1.32

W 4178

= = =

Vi < 5, m < 5 va fw

A1

A> , tra bang D9, Phu luc D cua TCXDVN 338 : 2005 Thiet ke ket cau

thep, ta co he so c tnh theo cong thc:

= (1.9 0.1m) 0.02(6 m)



mex = xmx = 3.83 mey = ymy = 3.55

d. Kiem tra bend. Kiem tra bend. Kiem tra bend. Kiem tra ben

Cot chu nen uon c kiem tra ben theo cong thc:

yxc

n nx ny

4 8 8

2 2

MMN y x fA I I

6314 100.56 85.67VT 0.32 0.25932 10 106018 10 104455 10120800(kN / m ) 220000(kN / m )

+ +

= + +

= <

Vay cot thoa ieu kien beVay cot thoa ieu kien beVay cot thoa ieu kien beVay cot thoa ieu kien ben.n.n.n.

e. Kiem tra on nh tong thee. Kiem tra on nh tong thee. Kiem tra on nh tong thee. Kiem tra on nh tong the

On nh tong the theo phng X : Vi x = 1.52 va mex = 3.55, tra bang D10, Phu luc D cua TCXDVN 338 : 2005 Thiet ke ket cau thep, ta co he so ex = 0.291. On nh tong the cua cot theo phng X c kiem tra theo cong thc:

2 24

N 6314 203421.4kN/ m f 220000kN / mA 0.291 932 10

= = < =

Vay cot thoa ieu kien on nh tong the theo phng XVay cot thoa ieu kien on nh tong the theo phng XVay cot thoa ieu kien on nh tong the theo phng XVay cot thoa ieu kien on nh tong the theo phng X

On nh tong the theo phng Y : Vi y = 1.55 va mey = 3.83, tra bang D10, Phu luc D cua TCXDVN 338 : 2005 Thiet ke ket cau thep, ta co he so ey = 0.302. On nh tong the cua cot theo phng Y c kiem tra theo cong thc:

2 24

N 6314 190912.7kN / m f 220000kN / mA 0.302 932 10

= = < =

Vay cot thoa ieu kien on nh tong the theo phnVay cot thoa ieu kien on nh tong the theo phnVay cot thoa ieu kien on nh tong the theo phnVay cot thoa ieu kien on nh tong the theo phn g Yg Yg Yg Y

f. Kiem tra on nh cuc bof. Kiem tra on nh cuc bof. Kiem tra on nh cuc bof. Kiem tra on nh cuc bo

Kiem tra on nh cuc bo cho ban bung: gia tr gii han [ hw/tw] oi vi cot chu nen lech tam c lay theo Bang 33, TCXDVN 338 : 2005 Thiet ke ket cau thep. Ta co:

82 2w1

w

h E 2.1 10(1.3 0.1 ) (1.3 0.1 1.52 ) 37.8t f 220000

= + = + =

Trong o ta co 1 x = ( oi vi tiet dien hnh hop, gia tr cua [ hw/tw] lay cho ban bung

nam song song vi mat phang tac dung cua moment uon)



w w

w w

h h54 13.5 37.8t 3 t

= = < =

Vay ban bung thoa ieu kien on nh coVay ban bung thoa ieu kien on nh coVay ban bung thoa ieu kien on nh coVay ban bung thoa ieu kien on nh co c bo.c bo.c bo.c bo.

Kiem tra ieu kien on nh cuc bo cho ban canh : oi vi cot co tiet dien hnh hop, th gia tr gii han [ b0/tf ] c lay giong nh oi vi ban bung. Ta co:

82 201

f

b E 2.1 10(1.3 0.1 ) (1.3 0.1 1.55 ) 38.0t f 220000

= + = + =

Trong o ta co 1 y = ( oi vi tiet dien hnh hop, gia tr cua [ b0 /tf] lay cho ban canh

nam song song vi mat phang tac dung cua moment uon)

0 0

f f

b b50 16.7 38.0t 3 t

= = < =

Vay ban canh thoa ieu kien on nh cuc bo.Vay ban canh thoa ieu kien on nh cuc bo.Vay ban canh thoa ieu kien on nh cuc bo.Vay ban canh thoa ieu kien on nh cuc bo.

Kiem tra cot chong tamKiem tra cot chong tamKiem tra cot chong tamKiem tra cot chong tam co tiet dien ch I to hp 400x600co tiet dien ch I to hp 400x600co tiet dien ch I to hp 400x600co tiet dien ch I to hp 400x600 ( kingpost loai 2)( kingpost loai 2)( kingpost loai 2)( kingpost loai 2)

TTTTTTTT V trV trV trV tr Tiet dien (mm)Tiet dien (mm)Tiet dien (mm)Tiet dien (mm) Lc doc Lc doc Lc doc Lc doc



My (kNm)My (kNm)My (kNm)My (kNm)

1 Cot goc Ch I to hp

400x600x30x30 3465 21.56 15.62

a. Xac nh chieu dai tnh toana. Xac nh chieu dai tnh toana. Xac nh chieu dai tnh toana. Xac nh chieu dai tnh toan

Chieu dai tnh toan trong mat phang khung lx = 0.7x6 = 4.2m

Chieu dai tnh toan ngoai mat phang khung ly = 4.2m

b. Xac nh o lech tam va tiet dien cotb. Xac nh o lech tam va tiet dien cotb. Xac nh o lech tam va tiet dien cotb. Xac nh o lech tam va tiet dien cot

o lech tam:

X0X X 0

Y0Y Y 0

M 21.56e 100 0.56cm e e e' 0.56 5 5.56cm

N 3465M 15.62

e 100 0.40cm e e e' 0.40 5 5.40cmN 3465

= = = = + = + =

= = = = + = + =

Vi e = 5cm la o lech tam cho phep khi thi cong cot chong tam.

Chon tiet dien cot chong tam co cac kch thc nh sau:



Hnh.5.4. Cau tao tiet dien cot chong tam loai 2 c. Cac dat trng tiet dienc. Cac dat trng tiet dienc. Cac dat trng tiet dienc. Cac dat trng tiet dien

A (cm2)

IX (cm4)

IY (cm4)

WX (cm3)

WY (cm3)

rX (cm)

rY (cm)

X (cm)

Y (cm)

402 39546 32122 1465 1606 9.92 8.94 42.35 46.99

Ta co XXXX va YYYY eu nho hn o manh gii han [] = 120] = 120] = 120] = 120

x x 8f 220000

=42.35 =1.72E 2.110

=

y y 8f 220000

=46.99 =1.90E 2.110

=

d. o lech tam tng oi m va o lech tam tnh oi md. o lech tam tng oi m va o lech tam tnh oi md. o lech tam tng oi m va o lech tam tnh oi md. o lech tam tng oi m va o lech tam tnh oi m eeee

xx

x

e A 5.56 402m 1.53

W 1465

= = =

YY

Y

e A 5.40 402m 1.35

W 1606

= = =

Vi < 5, m < 5 va fw

A1

A> , tra bang D9, Phu luc D cua TCXDVN 338 : 2005

Thiet ke ket cau thep, t a co he so c tnh theo cong thc:

= (1.9 0.1m) 0.02(6 m)



mex = xmx = 4.34 mey = ymy = 4.30

d. Kiem tra bend. Kiem tra bend. Kiem tra bend. Kiem tra ben

Cot chu nen uon c kiem tra ben theo cong thc:

yxc

n nx ny

4 8 8

2 2

MMN y x fA I I

3465 21.56 15.62VT 0.3 0.2402 10 39546 10 32122 10122256(kN / m ) 220000(kN / m )

+ +

= + +

= <

Vay cot thoa ieu kien ben.Vay cot thoa ieu kien ben.Vay cot thoa ieu kien ben.Vay cot thoa ieu kien ben.

e. Kiem tra on nh tong thee. Kiem tra on nh tong thee. Kiem tra on nh tong thee. Kiem tra on nh tong the

On nh tong the theo phng X : Vi x = 1.72 va mex = 4.34, tra bang D10, Phu luc D cua TCXDVN 338 : 2005 Thiet ke ket cau thep, ta co he so ex = 0.281. On nh tong the cua cot theo phng X c kiem tra theo cong thc:

2 24

N 3465 202150kN/ m f 220000kN/ mA 0.281 402 10

= = < =

Vay cot thoa ieu kien on nh tong the theo phng XVay cot thoa ieu kien on nh tong the theo phng XVay cot thoa ieu kien on nh tong the theo phng XVay cot thoa ieu kien on nh tong the theo phng X....

On nh tong the theo phng Y : Vi y = 1.90 va mey = 4.30, tra bang D10, Phu luc D cua TCXDVN 338 : 2005 Thiet ke ket cau thep, ta co he so ey = 0.278. On nh tong the cua cot theo phng Y c kiem tra theo cong thc:

2 24

N 3465 202482kN/ m f 220000kN/ mA 0.278 932 10

= = < =

Vay cot thoa ieu kien on nh tong the theo phng YVay cot thoa ieu kien on nh tong the theo phng YVay cot thoa ieu kien on nh tong the theo phng YVay cot thoa ieu kien on nh tong the theo phng Y....

f. Kiem tra on nh cuc bof. Kiem tra on nh cuc bof. Kiem tra on nh cuc bof. Kiem tra on nh cuc bo

Kiem tra on nh cuc bo cho ban bung: gia tr gii han [ hw/tw] oi vi cot chu nen lech tam co m > 1 va 1 < 2, tiet dien ch I c lay theo Bang 33, TCXDVN 338 : 2005 Thiet ke ket cau thep nh sau:

82 2w1

w

h E 2.1 10(1.3 0.1 ) (1.3 0.1 1.72 ) 39.5t f 220000

= + = + =

Trong o ta co 1 x = ( oi vi tiet dien ch I, gia tr cua [ hw/tw] lay cho ban bung nam song

song vi mat phang tac dung cua moment uon)



w w

w w

h h54 18 39.5t 3 t

= = < =

Vay ban bung thoa ieu kien on nh coc bo.Vay ban bung thoa ieu kien on nh coc bo.Vay ban bung thoa ieu kien on nh coc bo.Vay ban bung thoa ieu kien on nh coc bo.

Kiem tra ieu kien on nh cuc bo cho ban canh : oi vi cot co tiet dien ch I, th gia tr gii han [ b0/tf ] c lay theo Bang 35, TCXDVN 338 : 2005 Thiet ke ket cau thep nh sau :

80

f

b E 2.1 10(0.36 0.1 ) (0.36 0.1 1.9) 13.57t f 220000

= + = + =

Trong o ta co y =

0 0

f f

b b40 13.3 13.57t 3 t

= = < =

Vay ban canh thoa ieu kien on nh cuc bo.Vay ban canh thoa ieu kien on nh cuc bo.Vay ban canh thoa ieu kien on nh cuc bo.Vay ban canh thoa ieu kien on nh cuc bo.

Vay, vi 2 loai tiet dien a chon, cot am bao kha nang chu tai va on nh trong suot thi gian thi cong.

5.2. THIET KE CAC SHEATHIET KE CAC SHEATHIET KE CAC SHEATHIET KE CAC SHEAR STUD R STUD R STUD R STUD (INH CHONG CAT)(INH CHONG CAT)(INH CHONG CAT)(INH CHONG CAT) 5.2.1. Quan iem thiet keQuan iem thiet keQuan iem thiet keQuan iem thiet ke

Trong suot qua trnh thi cong tang ham theo phng phap topdown th kingpost (cot chong tam) gi vai tro rat quan trong la chu toan bo tai trong cua cac tang noi va cac tang ham thay cho cot chu lc cua cong trnh. Cho nen, thiet ke kingpost am bao chu c toan bo tai trong cong trnh trong qua trnh thi cong la mot nhiem vu quan trong. Mot nhiem vu na khong kem phan quan trong quyet nh s thanh bai qua trnh thi cong tang ham o chnh la giai quyet lien ket gia kingpost va cau kien cong trnh tai cac v tr:

Thiet ke tai v tr kingpost giao vi he dam san tang ham am bao chong lc cat t dam san tang ham truyen xuong kingpost.

Thiet ke do sau cam kingpost vao coc barrette e am bao cho kingpost truyen tai trong t cac tang tren xuong coc barrette mot cach an toan ma khong gay pha hoai coc.

Khi cam kingpost vao coc barrette hay tai v tr giao gia kingpost va dam san tang ham th gia be tong va be mat kingpost co phat sinh mot lc ma sat nhat nh chong lai lc cat sinh ra tai nhng v tr giao nay. Nhng bo bo qua s co mat cua lc ma sat gia be tong va kingpost, sinh vien chon giai phap thiet ke cac shear stud tai cac v tr nay e chong lc cat. Khi o, toan bo lc doc t cong trnh se c cac shear stud truyen qua be tong cua coc barrette.



5.2.2. Thiet ke shear stud cho oan kingpost cam vao coc barretteThiet ke shear stud cho oan kingpost cam vao coc barretteThiet ke shear stud cho oan kingpost cam vao coc barretteThiet ke shear stud cho oan kingpost cam vao coc barrette

5.2.2.1. Lc doc ln nhat truyen xuong chan cot:Lc doc ln nhat truyen xuong chan cot:Lc doc ln nhat truyen xuong chan cot:Lc doc ln nhat truyen xuong chan cot:

oi vi kingpost loai 1 (hnh hop 500x640x30x30): Nmax = 6314kN

oi vi kingpost loai 2 (ch I400x600x30x30): Nmax = 3465kN

5.2.2.2. Kha nang chu cat cua shear studKha nang chu cat cua shear studKha nang chu cat cua shear studKha nang chu cat cua shear stud

Theo tieu chuan thiet ke BS 5950 3.1 cua Anh quy nh, kha nang chu cat cua mot shear stud phu thuoc vao ng knh shear stud va cng o chu nen mau th be tong 28 ngay nh sau:

Cap o ben cua be tong lam coc barrette la B25, ta chon shear stud co ng knh d = 19mm, chieu cao danh ngha la h0 = 100mm, chieu cao lam viec la h = 95mm co kha nang chu cat tieu chuan la Qtc = 100kN.

Hnh.5.5. Hnh shear stud chong cat e xac nh kha nang chu cat tnh toan Qtt cua mot shear stud, trong tieu chuan quy nh he so an toan lay bang 1.51.8.

ttQ 100Q 58.88kNk 1.7

= = =



So lng shear stud can bo tr cho chan kingpost am bao kha nang chu cat la:

Kingpost loai 1: 1max1tt

N 6314n 107.23(Shear stud)Q 58.88= = =

Kingpost loai 2: 1max1tt

N 3465n 58.84(Shear stud)Q 58.88= = =

5.2.2.3. Bo tr shear studBo tr shear studBo tr shear studBo tr shear stud

Viec bo tr shear stud sao cho am bao kha nang chu lc toi a cua chung la mot eu rat can thiet, theo trong tieu chuan e ngh bo tr shear st ud nh sau:

Khoang cach toi thieu gia 2 shear stud gan nhau nhat tnh t tam en tam la khong qua 5 lan ng knh cua shear stud, vay lmin 5 x 19 = 95mm.

Khoang cach nho nhat tnh t tam shear stud en mep kingpost la 20mm.

Vay, chon cach bo tr cho cac shear stud nh sau:

Kingpost loai 1: khoang cach gia cac shear stud la 150mm, bo tr eu cho 4 mat cua kingpost, moi mat la 30 shear stud.

Kingpost loai 2: khoang cach gia cac shear stud la 150mm, bo tr eu cho 4 mat cua kingpost, moi mat la 15 shear stud.

Hnh.5.6. The hien khoang cach nho nhat t mep kingpost en shear stud

Ket qua bo tr shear stud cho oan kingpost cam vao coc barrette nh sau:



Hnh.5.7. Bo tr shear stud cho oan cot kingpost loai 1 cam vao coc barrette



Hnh.5.8. Mat cat 1-1

Hnh.5.9. Bo tr shear stud cho oan cot kingpost loai 2 cam vao coc barrette



Hnh.5.10. Mat cat 2-2

Hnh.5.11. Thc te s bo tr shear stud chong cat cho kingpost 5.2.3. Thiet ke shear stud cho oan kingpost giao vi dam san tang hamThiet ke shear stud cho oan kingpost giao vi dam san tang hamThiet ke shear stud cho oan kingpost giao vi dam san tang hamThiet ke shear stud cho oan kingpost giao vi dam san tang ham

Lc cat tnh toan cho cac shear stud tai v tr nay c lay t:

Hoat tai thi cong dam san tang ham: p = 20kN/m2 (lay cho san co hoat tai thi cong ln nhat la san tret)

Psan = 8.5 x 8.0 x 20 = 1360 kN

Trong lng do ket cau dam san tang ham truyen vao:

Gsan = 8.5 x 8.0 x 0.3 x 25 + 0.3 x 0.7 x 8.5 x 25 + 0.3 x 0.7 x 8 .0 x 25 = 596.6 kN

Lc cat gay ra tai v tr giao gia kingpost va dam san tang ham la :

Q = Psan + Gsan = 1360 + 596.6 = 1956.6kN

Chon loai shear stud co kha nang chong cat tng t nh a chon cho oan kingpost cam vao au coc barrette, khi o so lng shear stud can bo tr cho oan shear stud giao vi dam san tang ham se la:

1tt

Q 1956.6n 33.23(Shear stud)Q 58.88= = =

Chon 36 cay shear stud bo tr eu cho 4 mat (moi mat 9 cay) va khoang cach gia cac cay la 150mm.



Hnh.5.12. Bo tr shear stud cho oan cot giao vi san tang ham

Hnh.5.13. Thc te s bo tr shear stud chong cat cho kingpost

Documents

Kingpost Design