chuong 3 - dam thep
DESCRIPTION
Dam ThepTRANSCRIPT
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CHNG 3DM THPCh yu chu M v VChia 2 loi: dm hnh v dm t hp.
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Nhng K trong thit k dmTha K chu lc ti tit din nguy him.Bn bng, bn cnh tha iu kin chu lc cc b v lc tp trung.Tha K vng.Tha K n nh tng th.Tha K cu to v kh thi.
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Thit k dm thp hnhChn tit dinKim tra bnKim tra n nh tng thCu to v tnh ton cc chi tit
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Chn tit din dm hnhTheo s kt cu, xc nh M v VXc nh moment khng un yu cu:
Tra bng quy cch thp cn nng, chn li dm hnh tha:
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Kim tra K bn v unXc nh li M c k trng lng bn thn dm.Kim tra theo cng thc:
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Kim tra K bn chu ctXc nh li V c k trng lng bn thn dm.Kim tra theo cng thc Jurapski:
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Kim tra bn bng chu ng sut cc b
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Kim tra bn bng chu ng sut cc b (tt)
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Kim tra tit din chu ng thi , v c
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Kim tra vng dmVi dm n gin, nhp L chu ti trng phn b u:
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Kim tra n nh tng th dm
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THIT K DM T HPCng trnh chu ti trng ln (q>20kN/m).Nhp ln (L>12m).Trnh t: chn tit din, kim tra bn, bin dng, n nh, cu to v tnh ton cc chi tit.
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hmin h hkt (hmax)Chn chiu cao dm
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W =
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Xc nh chiu dy bn bngCoi nh bn bng ch chu lc ct Vmax
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Xc nh chiu dy bn bng (tt)
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Xc nh kch thc cnh
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Xc nh kch thc cnh (tt)
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Kim tra bnTheo K chu un:
Theo K chu ct:
Ti tit din chu ng thi M v V:
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Kim tra bn chu ng sut cc b bn bng Khi bn bng khng c sn gia cng:
Kim tra dm chu , v c:
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Kim tra vngKhi chn h hmin th khng cn kim tra vng.
Nu khng th kim tra vng:
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KiM TRA N NH TNG TH
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tnh b cn theo trnh t: tnh , tra bng 3.4 tm , tnh 1, tnh b Ch : s dng cho dm I n gin
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Cc trng hp khng cn kim tra n nh tng thC bn sn thp hoc BTCT.Khi tha iu kin:
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Cc bin php tng cng n nh tng thXem xt vic s dng bn sn.iu chnh t s bf/tf hay bf/hf tha mn biu thc trn.Gim nhp tnh ton ngoi mt phng cho cnh nn dm (b tr thm h ging, thanh chng ngang).
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n nh cc b bn cnh
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n nh cc b bn cnh (tt)ng sut ti hn:
Quan nim mt n nh khi cr = f
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n nh cc b bn bngDo ng sut tip (do V):
Cho cr = fv, suy ra:
Ch : ti trng tnh tc dng
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n nh cc b bn bng (tt)Khi th tha iu kin n nh bn bng.Ngc li phi gia cng sn ngang.
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n nh cc b bn bng (tt)Khi b tr sn ngang nh trn th mnh quy c thay i nh sau:Nu lc ny th bn bng t K n nh
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n nh cc b bn bng (tt)
Do ng sut php:
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n nh cc b bn bng (tt)iu kin khng ch:
Khi t s hw/tw vt qu gi tr trn th bn bng b mt n nh cc b.Cn phi gia cng sn dc.
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n nh cc b bn bng (tt)Do tc dng ng thi ca ng sut php v ng sut tip:Trng hp th 1: khi khng c ti trng tp trung (c = 0) v
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n nh cc b bn bng (tt)Trng hp th 2: khi c ti trng tp trung (c 0) v
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CU TO V TNH TON CC CHI TiT DM HNHLin kt bn bng v cnh:
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Cu to mi ni dm
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Cu to mi ni dm (tt)
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Cu to mi ni dm (tt)
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Cu to mi ni dm (tt)
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Cu to mi ni dm (tt)
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Cu to mi ni dm (tt)
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Cu to mi ni dm (tt)
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TNH TON MI NI DM T HP
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Dng lin kt bulong ni dm
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Dng lin kt bulong ni dm (tt)Tng din tch cc bn ni khng nh hn din tch thp c bn.Khi ni cnh: nu l bulong chim 15% din tch bn ni th ly tit din thc ca bn ni ( tr i tit din gim yu do l khot).
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Dng lin kt bulong ni dm (tt)Moment un tc dng ti mi ni:
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Dng lin kt bulong ni dm (tt)Trnh t tnh ton: Chn trc ng knh bulong v kch thc bn ghp.Tnh ton kim tra mi ni bng: chn trc s hng bulong nw cho 1 bn mi ni (chn theo khong cch min), tnh ton theo cng thc (khi ch c M):
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Dng lin kt bulong ni dm (tt)
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Dng lin kt bulong ni dm (tt)Khi c M v V tc dng ng thi (V ch do bn bng chu):
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Dng lin kt bulong ni dm (tt)Kim tra mi ni cnh: S bulong mt bn mi ni:
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CHNG 4: CT C CHU NN NG TM V LCH TMS tnh u ct: ngang khp c nh, dc ngm trt.Chn ct: khp, ngm.Khung: u ct lin kt cng.Ct chu nn ng tm: u ct LK khp.Chiu di tnh ton: L0 = .L: h s chiu di tnh ton (ph thuc s tnh), tra bng 4.1
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mnh ca ct
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CT C CHU NN NG TM
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Tnh ton ct c chu nn ng tmTnh ton v bn:
Tnh ton n nh tng th:
min tra bng II.1 ph lc II ty theo max
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Tnh ton ct c chu nn ng tm (tt)Tnh ton n nh cc b: xt mnh ca tng bn bng hay bn cnh.
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Tnh ton ct c chu nn ng tm (tt)Tnh ton v bn:
Tnh n nh tng th:
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Tnh ton ct c chu nn ng tm (tt)Tnh ton n nh cc b:
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Tnh ton ct c chu nn ng tm (tt)
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Tnh ton ct c chu nn ng tm (tt)
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Xc nh tit din ct c chu nn ng tm
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Xc nh tit din ct c chu nn ng tm (tt)
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Xc nh tit din ct c chu nn ng tm (tt)
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Xc nh tit din ct c chu nn lch tm, nn un