Team Member:

1
Design of Concrete Girder Bridge
UNITED ARAB EMIRATES UNIVERSITY College of
Engineering Civil Environmental Engineering
Department
Graduation Project II

• Team Member
• Ahmed Al-Shehhi 200000069
• Waleed Al-Alawi 200101647
• Abdullah Al-Neyadi 200101637
• Hassan Al-Hassani 200005052
• Projects advisor Bilal El-Ariss

2
Presentation outline

• Executive Summary
• Introduction
• Background theory
• Methods and Techniques
• Analysis of pier cap
• Design of bridge deck ,girders and pier cap
• Results and discussions
• Conclusions and recommendations

3
Executive Summary

• Analysis and design of a concrete girder bridge
• Graduation project I
• Graduation project II
• Pier cap analysis
• Design of bridge deck , girders and pier cap

4
Executive Summary

• Software used
• SAP2000
• Analysis and determine bending moments and shear
  forces
• PROKON
• Compute the reinforcement areas needed for the
  shear and moments, and the dimensions of the
  different components of the bridge

5
Introduction

• Project description
• Bridge location

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Introduction

• Project description
• Continuous girder bridges .
• Two lanes in each direction and two shoulders and
  carries the traffic in two directions .
• Two span girders .

7
Introduction

• Bridge Dimensions

198 ft Total Bridge length
2 No. of spans
99 ft Length of span
60.74 ft Total bridge width
12.635 ft Two lanes each lane width
3.75 ft Side walk width
8 No. of girders
7.22 ft Distance between girders
5.1 ft Cantilever length
8
Introduction

• AASHTO specifications
• American Concrete Institute (ACI) code

9
Introduction

• Bridge location
• Abu Samra Bridge is located on the high way
  between Abu Dhabi and Al-Ain .

10

Background Theory

• Reinforcement requirements
• Design method
• Reinforcement requirements due to flexure
• Reinforcement requirements due to Shear
• T-Girder

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Design method

• The method which will be used in our project is
  the ultimate-strength design method.
• It's called now ultimate strength design.
• The working dead and live loads are multiplied by
  certain load factors and the resulting values are
  called factored loads.

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Reinforcement requirements due to flexure

• The reinforcing bars will be distributed as
  follows
• This reinforcing may not be spaced farther on
  center than 3 times the slab thickness.
• A percentage of the main positive moment
  reinforcement which is perpendicular to the
  traffic shall be distributed in the parallel
  direction of the traffic

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Reinforcement requirements due to flexure

• Spacing limits for reinforcement
• For cast-in-place concrete the clear distance
  between parallel bars in a layer shall not be
  less that 1.5 bar diameter.
• Not less than1.5 times the maximum size of the
  coarse aggregate or 1.5 inches.

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Reinforcement requirements due to flexure

• Positive Moment Reinforcement
• At least one-third the positive moment
  reinforcement in simple members and one-fourth
  the positive moment reinforcement in continuous
  members shall extend along the same face of the
  members into the support in beams, such
  reinforcement shall extend into the support at
  least 6 inches.
• The development length
• The reinforcement bars must be extended some
  distance back into the support and out into the
  beam to anchor them or develop their strength.

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Reinforcement requirements due to Shear

• The failure of reinforced concrete beams in shear
  are quite different form their failures in
  bending.
• Shear failures occur suddenly with little or no
  advance warning.
• If pure shear is produced in a member, a
  principal tensile stress of equal magnitude will
  be produced on another plane.

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Types of Shear Reinforcement

• Stirrups perpendicular to the axis of the member
  or making an angle of the member or making and
  angle of 45 degrees or more with the longitudinal
  tension reinforcement.
• Welded wire fabric with wires located
  perpendicular to the axis of the member.
• Longitudinal reinforcement with a bent portion
  making an angle of 30 degrees or more with
  longitudinal tension reinforcement.
• Combinations of stirrups and bent longitudinal
  reinforcement.
• Spirals.

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Shear strength

• Design of cross section subject to shear shall be
  based on
• Where Vn nominal shear strength
• Vu factored shear force at the section
  considered

18
Shear strength provided by concrete

• For members subjected to shear and flexure only
  (Vc) is computed by
• Where bw the width of web
• d the distance from the extreme compression
  fiber to the centroid of the longitudinal tension
  reinforcement.

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Shear strength provided by Shear Reinforcement

• When shear reinforcement perpendicular to the
  axis of the member is used
• Where Av the area of shear reinforcement with in
  distance s.
• S Spacing between stirrups
• Shear Strength Vs shall not be taken greater than
  

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Minimum shear reinforcement

• A minimum area of shear reinforcement shall be
  provided in all flexural members expect slab and
  footing where the factored shear force Vu exceeds
  one-half the shear strength
  provided by concrete 1/2.
• The area provided shall not be less than
• Where b and s are in inches.

21
Minimum shear reinforcement

• Spacing of Shear Reinforcement
• Spacing of shear reinforcement placed
  perpendicular to the axis of the member shall not
  exceed d/2 of 24 inches.
• Shrinkage temperature reinforcement
• Reinforcement for shrinkage and temperature
  stress shall be provided near exposed surfaces of
  walls and slabs not otherwise reinforced.
• The total area of reinforcement provided shall be
  at least 1/8 square inch per foot in each
  direction.
• The spacing of shrinkage and temperature
  reinforcement shall not exceed three times the
  wall or slab thickness, or 18 inches

22
Girder ( T Section )

• The Total width of slab effective as a T-girder
  flange shall not exceed one-fourth of the span
  length of the girder.
• The effective flange width overhanging on each
  side of the web shall not exceed six times the
  thickness of the slab or one-half the clear
  distance to the next web.

23
Recommended Minimum Depths for Constant Depth
Members.
24
Analysis of Pier Cap
25
Analysis of Pier Cap

• Dead load of pier cap
• Live load of pier cap

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Dead load of pier cap

• Estimate the thickness
• L 50.54 ft
• Length of span 25.27 ft
• Minimum thickness of the bridge cap piers
• Width (b) 0.5 Depth 3 ft

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Dead load of pier cap

• Own weight of pier cap Density of conc. area
  1
• 150 Ib/ft 3 (6 3) 1
  
• 2700 Ib/ft
• Uniform wheel load wheel load S/6 Impact
  factor
• 26 kip
• Concentrated load from interior girder
• 490 Ib
• Concentrated load from interior girder
• 546 Ib

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Dead load of pier cap
Dead load
B.M.D
Shear force diagram
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Live load of pier cap

• Use several cases by distributing the wheel
  trucks.
• Take the maximum wheel load 18000 Ib
• Find the reactions in each supports for all
  cases.
• Take the maximum values of reaction.

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Live load of pier cap

• These are the following cases
• Case 1 Full shift left
• Case 2 Full shift right
• Case 3 Centre to left
• Case 4 Centre to right
• Case 5 one truck centre to left
• Case 6 one truck to left
• Case 7 one truck centre to right
• Case 8 one truck to right

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Live load of pier cap

• Example of calculationsCase 3 Centre to left

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Live load of pier cap
Uniform wheel load

• ? M2 0
• R1 ( 26 2.95 ) / 7.22 10.6 k
• ? Fy 0
• 10.6 R2 26 0
• R2 15.4 k
• ? M3 0
• R2 ( 26 4.17 ) / 7.22 15 k
• ? Fy 0
• 15 R3 26 0
• R3 11 k

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Live load of pier cap

• Reactions for eight cases

R8 R7 R6 R5 R4 R3 R2 R1
47.61 14.59 30.39 30.4 32 33.15 20.67 52.72 Cases 1
52.72 19.41 32.95 32.05 30.39 30.4 29.1 32.98 Cases 2
32.2 12.6 30.576 30.39 30.39 30.576 34.6 21.92 Cases 3
17.18 8.82 34.76 10.98 10.98 19.41 15.4 10.6 Cases 4
0 0 0 2.4 25 12.2 0 0 Case 5
0 0 0 0 0 14.5 29.4 24.6 Case 6
0 0 11.1 27.9 20.2 0 0 0 Case 7
10.8 12.2 23.4 0 0 0 0 0 Case 8
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Maximum Values in Dead Load
Distance Maximum Shear Force
25.27 ft 104.57 kips
   
Distance Maximum positive moment
16.2346 ft 138.72 k-ft
   
Distance Maximum negative moment
25.27 ft 245.59 k-ft
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Maximum Values in Live Load

• Found the maximum in the same position of maximum
  dead load

Maximum Case 8 Case 7 Case 6 Case 5 Case 4 Case 3 Case 2 Case 1  
166.92 k 51.88 k 51.88 k 52.56 k 13.9 k 166.26 k 166.15 k 166.92 k 165.85 k Max. shear force
281.89 k-ft 48.63 k-ft Zero 7.52 k-ft Zero 270.27 k-ft 274.2 k-ft 281.89 k-ft 261.44 k-ft Max. positive moment
510.36 k-ft 60.1 k-ft 60.1 k-ft 70.47 k-ft 65.01 k-ft 510.36 k-ft 509.3 k-ft 502.89 k-ft 504.3 k-ft Max. negative moment
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Maximum Values in Live Load
Maximum shear force in case 2
Maximum positive moment in case 2
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Ultimate Moment Shear
271.49 k DL shear LL shear
420.61 k-ft DL pos. moment LL pos. moment
755.95 k-ft DL neg. moment LL neg. moment
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Design Stage
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Design of girder bridge

• Design of slab by using Prokon software
• Design the girders using manual calculation
  method
• Design the pier cap by using Prokon software.

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Design of Slab (Inputs)

• Use PROKON for slab
• Inputs Slab cross section

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Design of Slab (Inputs)
42
Design of Slab (Inputs)
43
Design of Slab (Inputs)
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Design of Slab (Outputs)
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Design of Slab (Outputs)

• Area of steel (As)

Bars As (Top) mm2 Bars As (Bottom) mm2
4 ? 22 1430 5 ? 16 924 Cantilever
8 ? 10 564 4 ? 16 614 Middle
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Design of Girder (Inputs)

• Use Hand Calculations Method

Negative Positive
2033.73 KN-m 4745.37 KN-m Interior
2033.73 KN-m 4745.37 KN-m Exterior
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Design of Girder

• Positive section
• The following equations were used to compute Area
  of steel needed for the section (As)
• Fy 420 MPa
• Fc 21 MPa
• Mu 4745 KN-m
• b 2200.656 mm
• d 1601.4 mm

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Design of Girder
49
Design of Girder

• Minimum Spacing of stirrups Maximum of
• 600 mm
• .
• Use minimum Spacing (S) 600mm

50
Design of Girder
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Design of Pier Cap (Inputs)

• Using Prokon software to design
• Inputs
• Parameters
• Fcu,
• Fy,
• D.L and L.L factors
• density of concrete
• Length of each span 7.7 m

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Design of Pier Cap (Inputs)
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Design of Pier Cap (Outputs)
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Design of Pier Cap (Outputs)

• Minimum spacing s maximum of (depth
  cover)/2 (1829-
  50)/2 890 mm
• 
  600 mm
• So minimum spacing (s) 890 mm.
• Minimum number of bars length of span /
  Spacing 7700 / 890 8.6 9 bars
• Take 10mm Stirrups diameter for the pier cap

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Design of Pier Cap (Outputs)
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Design of Pier Cap (Outputs)
bars As- Bottom (mm2) bars As-Top (mm2)  
9 10 0 9 43 12,000 Middle
9 13 889 10 19 2560 First End
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Conclusion

• Finish the analysis of pier cap.
• Finish the design of superstructure for a girder
  bridge
• Use SAP2000 and Prokon programs in design
• The objective of GPII is fulfilled
• Learn main concepts on structural analysis and
  design