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1. Team Member:
Ahmed Al-Shehhi 200000069
Waleed Al-Alawi 200101647
Abdullah Al-Neyadi 200101637
Hassan Al-Hassani 200005052
Projects advisor : Bilal El-Ariss Design of Concrete Girder Bridge
2. Executive Summary
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 :
Analysis and determine bending moments and shear forces
Compute the reinforcement areas needed for the shear and moments, and the dimensions of the different components of the bridge
5. Project description
6. 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
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. Reinforcement requirements:
Reinforcement requirements due to flexure
Reinforcement requirements due to Shear
11. 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.
12. 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
13. 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.
14. 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. Reinforcement requirements due to flexure
15. 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.
16. 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.
17. 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.
19. 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
20. 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. 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 Minimum shear reinforcement
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.
25. Analysis of Pier Cap Dead load of pier cap
Live load of pier cap
26. 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
27. 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
28. Dead load of pier cap
29. 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.
30. 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
Live load of pier cap
31. Live load of pier cap Example of calculationsCase 3: Centre to left
32. Live load of pier cap
33. Live load of pier cap Reactions for eight cases
34. Maximum Values in Dead Load
35. Maximum Values in Live Load Found the maximum in the same position of maximum dead load
36. Maximum Values in Live Load
37. Ultimate Moment & Shear
39. 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.
40. Design of Slab (Inputs) Use PROKON for slab
Inputs: Slab cross section
41. Design of Slab (Inputs)
42. Design of Slab (Inputs)
43. Design of Slab (Inputs)
44. Design of Slab (Outputs)
45. Design of Slab (Outputs) Area of steel (As)
46. Design of Girder (Inputs) Use Hand Calculations Method
47. 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
48. Design of Girder
49. Design of Girder Minimum Spacing of stirrups = Maximum of
Use minimum Spacing (S) = 600mm
50. Design of Girder
51. Design of Pier Cap (Inputs)
52. Design of Pier Cap (Inputs)
53. Design of Pier Cap (Outputs)
54. 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
55. Design of Pier Cap (Outputs)
56. Design of Pier Cap (Outputs)
57. 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