portal pier

DESIGN OF PIER SECTIONS

DESIGN FORCES: Pier 1

V (t) ML (tm) MT (tm) V (t) ML (tm) MT (tm)

1036 266 1734 1230 809 542732 69 1430 926 271 786958 5 2132 1152 290 1449755 518 1454 1035 1211 1031

Pier 2V (t) ML (tm) MT (tm) V (t) ML (tm) MT (tm)928 260 1727 1122 745 625658 67 1374 852 248 815850 14 2029 976 93 1601731 512 1439 1018 1159 682

Minimum Reinforcement and Spacing

A) Minimum area of reinforcement required(Clause 15.9.4.1 of IRS Concrete Bridge Code)Lesser of a) 1% of cross section

b) 0.15 x P / fyMaximum Ultimate load on Pier, P = 1230 tfy = 500 Mpa

B) Minimum area of reinforcement required(Clause 16.2.2 of IRC:112)

Maximum Transverse MomentMaximum Longitudinal Moment

ULS Check (Bottom)

ULS Check (top) ULS Check (Bottom)CASEMaximum Vertical LoadMinimum Vertical Load

ULS Check (top)

CASE

Maximum Vertical LoadMinimum Vertical LoadMaximum Transverse MomentMaximum Longitudinal Moment

“Detailed Design Consultancy Services for Ten Elevated Metro Stations and Viaduct between Baranagar (Km

4571.00) to Barrackpur (Km 17200.00) in Baranagar-Barrackpur Corridor of Kolkata Metro Railway Line”

Design of Normal Pier of Height 13m (RTL-Pile Cap top Level)

) q ( )

Greater of a) Asmin = 0.002Acb) Asmin = 0.1NED/fyd

Maximum Design Axial Force, NED = 1230 tfyd = 435 Mpa

C) Check for Spacing of ReinforcementClear cover to reinforcement = 50 mmDiameter of Stirrups = 10 mmMaximum Permitted spacing as per Clause 15.9.4.1 of IRS Concrete Bridge Code

= 300 mmMaximum Permitted spacing as per Clause 16.2.2 of IRC:112 Code

= 200 mm

Type of pier used capsule with semi-circular edgePier dimension in direction along the traffic = 3.4 m with architectural groovesPier dimension in direction normal to traffic = 2.10 m with architectural groovesStructural Dimension of capsule type Pier with semi-circular edge = 2.00 x 3.25 mEquivalent Rectangular pier dimension considered ( D x B ) = 1.86 x 3.03 mArea of Structural Concrete = 5.64 SqmMin As as per IRS code (%) = 0.065Min As as per IRC code (%) = 0.200Min As to be adopted (%) = 0.200

% of Steel provided = 2.20 OKTotal No of Vertical Bars = 192Maximum Diamter of Bar used = 32 mmPerimeter at c/l of vertical bars = 8306 mmSpacing of Bar = 43.3 mm OKConcrete Grade = M50




ULS CheckPuz = 17134 t d`/D = 0.04d`= 76 mm d`/B = 0.03

pt/fck = 0.044

Pier 1 Top Section

Pu or V ( t)

ML (tm)

MT (tm)Pu /

(fckBD)*MuL/

(fckB2D)

*MuT/ (fckBD2)

1036 266 1734 0.037 0.090 0.090

732 69 1430 0.026 0.080 0.080

958 5 2132 0.034 0.087 0.087

755 518 1454 0.027 0.080 0.080

# MuL ( tm )

# MuT ( tm )

p/puz αn STATUS

7687 4730 0.060 1.00 OK

6833 4205 0.043 1.00 OK

7431 4573 0.056 1.00 OK

6833 4205 0.044 1.00 OK

* Values has been taken from Chart 47 of SP16.

#Moment Capacity corresponding to applied axial load' (tm)

Maximum Longitudinal Moment 0.42Maximum Transverse Moment 0.47

Load Case

Maximum Vertical Load

Minimum Vertical Load

Maximum Transverse Moment

Maximum Longitudinal Moment

Load Case(ML/MuL)αn + (MT/MuT)αn

Maximum Vertical Load 0.40

Minimum Vertical Load 0.35

Pier 1 Bottom Section

Pu or V ( t)

ML (tm)

MT (tm)Pu /

(fckBD)*MuL/

(fckB2D)

*MuT/ (fckBD2)

1230 809 542 0.044 0.095 0.095926 271 786 0.033 0.087 0.087

1152 290 1449 0.041 0.093 0.0931035 1211 1031 0.037 0.090 0.090

# MuL ( tm )

# MuT ( tm )

p/puz αn STATUS

8114 4993 0.072 1.00 OK7431 4573 0.054 1.00 OK7943 4888 0.067 1.00 OK7687 4730 0.060 1.00 OK

Pier 2 Top Section

Pu or V ( t)

ML (tm)

MT (tm)Pu /

(fckBD)*MuL/

(fckB2D)

*MuT/ (fckBD2)

928 260 1727 0.033 0.087 0.087658 67 1374 0.023 0.078 0.078850 14 2029 0.030 0.085 0.085731 512 1439 0.026 0.080 0.080

# MuL ( tm )

# MuT ( tm )

p/puz αn STATUS

7431 4573 0.054 1.00 OK6662 4100 0.038 1.00 OK7260 4468 0.050 1.00 OK6833 4205 0.043 1.00 OK

Load Case



Maximum Vertical Load 0.21

Load Case


Minimum Vertical Load 0.21Maximum Transverse Moment 0.33Maximum Longitudinal Moment 0.38

Maximum Transverse Moment 0.46Maximum Longitudinal Moment 0.42


Maximum Vertical Load 0.41Minimum Vertical Load 0.35




Pier 2 Bottom Section

Pu or V ( t)

ML (tm)

MT (tm)Pu /

(fckBD)*MuL/

(fckB2D)

*MuT/ (fckBD2)

1122 745 625 0.040 0.092 0.092852 248 815 0.030 0.085 0.085976 93 1601 0.035 0.089 0.089

1018 1159 682 0.036 0.090 0.090

# MuL ( tm )

# MuT ( tm )

p/puz αn STATUS

7858 4835 0.065 1.00 OK7260 4468 0.050 1.00 OK7601 4678 0.057 1.00 OK7687 4730 0.059 1.00 OK

Therefore Provide 60 Nos 32 Dia bar for Pier 1 and Pier 2 throughout the section ( top to bottom )

Check for Crack Width

Allowable Crack Width = 0.2 mm

V (t) ML (tm) MT (tm)Max. Comp. Stress in

Max. Tensile Stress in

STATUS

IA 753 171 1374 12 04 114 30 OK

Load Case Crack Width (mm)

0 099

Load Case

(ML/MuL)αn + (MT/MuT)αn

Maximum Vertical Load 0.22Minimum Vertical Load 0.22


Load Case

Maximum Transverse Moment 0.35Maximum Longitudinal Moment 0.29

IA 753 171 1374 12.04 114.30 OKIB 658 180 1023 9.28 79.78 OK

IC 701 3 1623 12.88 142.20 OK

IA 908 516 263 4.50 9.00 OK

IB 870 516 555 6.84 28.61 OK

IC 819 186 1127 10.13 80.71 OK

IA 679 167 1367 11.95 118.90 OK

IB 630 174 1304 11.49 115.30 OK

IC 627 8 1554 12.34 139.70 OK

IA 834 475 318 4.68 12.10 OK

IB 834 475 318 4.68 12.10 OK

IC 745 169 1149 10.22 88.00 OK

*For crack width calculation refer next page.

Provision of Vertical Reinforcement

Provide 96 Nos 32 Dia Bar at 1st Layer Equally spaced96 Nos 0 Dia Bar at 1st Layer Equally spaced96 Nos 25 Dia Bar at 2nd Layer Equally spaced96 Nos 0 Dia Bar at 2nd Layer Equally spaced

Ast Provided = 124332 Sqmm% of Steel Provided = 2.20

Provision of Lateral Reinforcement

For Confinement ZoneNormalised axial force nk =NED/(AC fck) = 0.04 Confinement of compression zone is not required(Clause 17.2.1.1 of IRC:112-2011)Length of plastic hinge required, Lh = 0 mm above pile cap (Clause 17.2.1.4 of IRC:112-2011)Longitudinal reinforcement ratio ρL = 0.022Confined(core) concrete area, ACC = 5.16 SqmMinimum reinforcement ratio ωw,req = 0.044 [ 0.37 (Ac/ACC) nk+0.13 (fyd/fcd)(ρL-0.01)]

>=2.2, Hence OK

0.0990.020

Pier 2 Top

Pier 2 Bottom

Pier 1 Top

Pier 1 Bottom

0.155

0.000

0.000

0.020

0.108

0.101

0.150

0.000

0.000

0.040




(Clause 17.2.1.2 of IRC:112-2011)Min. confining r/f reqd ωwd = 0.120 [ Max ( ww,req ; 0.12)] for Rectangular Stirrups.(Clause 17.2.1.2 of IRC:112-2011)volumetric ratio ρw = 0.007 [ (fcd/fyd)wwd] for Rectangular Stirrups.(Clause 17.2.1.1 of IRC:112-2011)Reqd. confining reinf. Asp/sL = 20754 Sqmm/m along Longitudinal Section(Clause 17.2.1.1 of IRC:112-2011) 12499 Sqmm/m along Transverse SectionRequired max. spacing sL = 200 mm(Clause 17.2.1.3 of IRC:112-2011)Required max. spacing sT = 200 mm and provided 173.0 mm(Clause 17.2.1.3 of IRC:112-2011)Reqd. confining reinf. Asp/sT = 1005 Sqmm/m [ So, min. link Dia shoud be(Clause 17.2.2 of IRC:112-2011)For Normal ZoneMin. diameter of transverse reinforcement req.= 8 mmRequired max. spacing sL = 200 mm(Clause 16.2.3 of IRC:112-2011)Required max. spacing sT = 300 mm and provided 259.6 mm(Clause 16.2.3 of IRC:112-2011)

Details of lateral reinforcement provided

Outer Stirrups

Dia. (mm) Dia. (mm) No. Dia. (mm)

No. Long. Section

Trans. Section

10 10 4 10 8 200 N.A. N.A. 0 N.A.

Inner Longitudinal Ties

Inner Transverse Ties Spacing

(mm)

Ast (Sqmm/m)Zone Status

Confinement

Length of zone

0 mm.]

10 10 4 10 8 200 N.A. N.A. 0 N.A.10 10 4 10 8 200 N.A. N.A. 0 N.A.10 10 4 10 8 200 N.A. N.A. 0 N.A.10 10 4 10 8 200 N.A. N.A. 0 N.A.10 10 4 10 8 200 3927 2356.19 8850 ok

Transition 3Normal

ConfinementTransition 1Transition 2

portal pier

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