ENCE 717abutment Calculation

7/26/2019 ENCE 717abutment Calculation

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ENCE 717BRIDGE ENGINEERING

ABUTMENT/PIER DESIGN(Ref: FHWA PSC Girder Design)

C. C. Fu, Ph.D., P.E.

The BEST CenterUniversity of Maryland

December 2008


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Integral Abutment Design (1)Pile Cap (7.1.2)

Stage I (noncomposite)

PSI = 1.25 x (girder + slab + haunch)

Final Stage (composite)

PFNL

= 1.25(DC) + 1.50 (DW) + 1.75(LL +

IM) (Nlanes)/Ngirders

Pile (7.1.3)

Case A Capacity of the pile

Case B Transfer load to theground

Case C Ground to support theload(assume rock, only Case A needs to be

investigated.)


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Integral Abutment Design (2)

Backwall (7.1.4) (80% of simple beam moment)

Case A -

Pu = 1.5 x (girder + slab)wu = 1.5 x (pile cap + diaphragm)

Case B -

PStr-I = factored girder reaction

wStr-I = 1.25(pile cap + end diaph. + approach slab) + 1.50

(approach FWS) + 1.75(approach slab lane load) (Nlanes)/Ngirders


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Backwall (7.1.4)

Passive pressure -

wp = 1/2 x z2kp

wu = 1.5 x wp


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Wingwall (7.1.5)

Passive pressure (kp=3) -wu at bottom of slab=0.2k/ft

2; at bottom of wall=3.24 k/ft2

Mp = (Rect. Volume x base length) + (pyramid volume x base length)

Active pressure (ka = 0.333) Ma = (ka/kp)*Mp +Mcollision

base length

1/4 base length


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Approach Slab (7.1.6)

Single lane loaded

E = 10 + 5 (L1

W1

)

Multiple lane loaded

E = 84 + 1.44 (L1W) 12W/NL

Mu = wl2/8 + 1.75 (LL+IM Moment)


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Intermediate Pier Design (1)


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Intermediate Pier Design (2)


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IntermediatePier Design (3)

Longitudinal

Braking force (BR)

Wind load along axes ofsuperstructure

Wind load on sub = Wcap + Wcol

Transverse

Wind load transverse to thesuperstructure

Wind load on sub

Wind on live load


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IntermediatePier Design (4)

Moment

1, 2 = P/LW M

l(L/2)(L3W/12)

5, 6 = P/LW M

t(L/2)(W3L/12)

Shear

Vux = 4L2 + 0.5(1 4)L2

Vuy = 8L4 + 0.5(5 8)L4

Two-way (punching shear)

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ENCE 717abutment Calculation