C(\ng hai bi~u d6 ap l\Ic thdm vii ap l\Ic tInh dfrY n6i len tdm day cong triOO ta duQ'c bi~u d6 t6ng ap l\Ic dfry n6i len tdm day cong trinh.
* f)~ don gian h6a bi~u d6 t6ng ap l\Ic dfry n6i len tdm day cong triOO cling Iii m(\t hiOO thang (HiOO 2.lg).
2. Tinh toan t6ng ap hrc day n6i len tam day cong trinh
* Pban bi~u d6 t6ng ap l\Ic dfry n6i len tdm day cong triOOthilnh 2 hiOO don giiln (hinh chCrOO~tvii hinh tam giac) d~ tiOOtoano
• WI = Yn.Sbi~u d6chfrnhat.B= Yn.(hB+Hz +t).L.B Phuong thiing dling, chi~u huang len.
* Wz = Yn .Sbieu~ii'amgiac.B =Yn.-!-(hA - hB).L.B
2
Phuang th~ng dUng, chi~u hUOng len.
Di€m d~t Iii tn;mg tam cua bi€u d6. (B la b~ r(\ngcua tfun day)
2.3. cAc THIET BJ CHONG TRAMDumDAy CONG TRiNH THirY LQI
2.3.1. Cae nguyen If chungd€ eh&ngth~m
I. Anh hutYng cua chiJu dt'JiiJutYngviJn th6m
- Keo dili duimg vi~n thfun v~ phia thuqng lUll thi W'hfun,V'hftm,q'hfund~u giam(giam t&.tcil cac tac h(li cua dong th&.m). (giam t&.tcil cac tac h(li cua dong th&.m).
Giai phap nay thuimg k~t hgp vai vi~c ch5ng xoi cho cua vilo nen thuimg duqc su d\lng r(\ng rai cho cong trinh tlr IOn d~n nho.
- Keo dili duimg vi~n th&.mv~ phia h(l lUll thi Wth&.mtang nhung V'hfun,qthftrnd~ugiam. giam.
Giai philp nily chi nen dung khi cong trinh kho co kha nang m&.t6n dinh va vi~c ch5ng xoi ng&m, troi d&.tla quan tr9ng.
- Rut ng~n duimg vi~n th&.m6 phia thuqng lUll thi W'hftrn,V'hfun,q'hftrnd~u tang(tang t&.tca cac tac h(li cua dong thfun). (tang t&.tca cac tac h(li cua dong thfun).
Giai phap nily chi dUng cho cong trinh nho, kinh phi h(ln hvp.
- Rut ng~n duimg vi~n th&.m6 phia h(l lUll thi W'hfungiam nhung V'hftm,qthftrnd~utang. tang.
Giai phap nily nen dUng khi cong trinh r&.td~ m&.t6n dinh (c(\t nuac thuqng lUll IOn). Luc nay c&nphili b5 tri thi~t bi 19Cnguqc t5t.
2. Anh hutYng cua hinh d(lng iJutYngviJn thdm
- Cac dO(ln duimg vi~n th&.mth~ng dUng vii nghieng co tac d\lllg tieu hao c(\tnuac th&.mhi~u qua han phuang ngang. Tuy nhien vi~c thi cong cac thi~t bi ch5ng nuac th&.mhi~u qua han phuang ngang. Tuy nhien vi~c thi cong cac thi~t bi ch5ng th&.mtheo phuang th~ng dUng (cu, tuimg ch~n ...) thuimg kho khan, t5n kern nen chi su d\lng 6 nhUng cong trinh vua vii IOn, quan tr9ng.
- Duimg vi~n thfun co d(lllg gay khuc co tac d\lng ch5ng th&.mti~p xuc t5t hand(lng th~ng. Vi~c thi cong d(lng gay khuc (d(lng chan khay, vilnh dai ch5ng thAm...) d(lng th~ng. Vi~c thi cong d(lng gay khuc (d(lng chan khay, vilnh dai ch5ng thAm...) ciing khong kh6 khan, t5n kern nhi~u nen thuimg duqc su d\lng f(\ng rai d~c bi~t Iii d(lng chan khay vi chlmg con Iilm tang 5n dinh v~ truqt cho cong trinh.
2.3.2. Cae thiit bi ehBngthdm trong cllng trinh thiiy IQi
1. San truO'c
D~ptrim
Lap da baa v~ Ddt set
Hinh 2.3. Siin tmac biing ddt set *Cdn tao'. .
- San truac b~g dill set (Hinh
2.3):
Chi~u dili san truac phl,lthuQc jF'
vilo nhi~u y~u t6 nhu dQ chenh m\IC nuac thuqng h~ luu, b~ dily tfrng thfun... Siin truac cilng dili tac dl,lllg cilng Ian tuy nhien tac
dl,lngcua san truac khong tang theo tYI~vm dQdili.
Chi~u dili san truac I~ytrong khoimg Lst=(375)H lil hgp Iy. H - Chi~u cao cQtnuac ap l\Ic th~m.
Theo yeu cfruch6ng th~m b~ dily san truac co th~ xac dinh theo cong thuc:
(2-8)
MI - DQ chenh cQt nuac th~m phia tren vil duai san truac t~i di~m tinh toano
[J] - Gradien th~m cho phep d6i vai v~t li~u lilm san truac.
- San truac b~ngda xay, betong, betong c6t thep (Hinh 2.4):
So vai san truac b~ng d~t set san truac b~ng da xay, betong, betong c6t thep co chi~u day (t) nho hon.
Hinh 2.4. San tmac biing da xay (be tong, betong c6t thep)
D~ptrim
* Tae d\lng:
- Keo dili duimg vi~n th~m v~ phia thuqng luu nen giam ap l\Ic th~m len t~m day cong trinh, giam luu luqng th~m, giam Vra. Vi th~ tang kha nang 6n dinh, giam m~t nuac, giam kha nang xoi ngfrmvil troi d~t... tuy nhien hi~u qua khong cao so vai cu thuqng luu (vi keo diliduimg vi~n th~m thea phuong nk ngang).