the socialist republic of viet nam
DESCRIPTION
engTRANSCRIPT
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TABLE OF CONTENTS
1.General 21.1Basic Design Concept 21.2List of bridge 21.3Major Change from Feasibility Study 21.4Typical Cross Section 4
2.Design conditions 52.1Applied Design Standards and Specifications 52.2Design Criteria 52.3Materials 7
3.Bridge of Package 8 83.1Review of span arrangement 83.2Substructure 123.3Superstructure of hollow slab girder 153.4Superstructure of I girder 19
General1.
1.1Basic Design Concept
Bridges and structures design in this project is for phase I. Phase II is considered only for a setting of vertical clearance.
Detailed design was carried out based on the result of Feasibility Study unless there was no change in design conditions such as future plans,geotechnical conditions and topographical conditions.
1.2List of bridge
Bridge and viaduct length, location and bridge type is shown in following table.
List of Bridge
Name of Bridge ChannelLength
(m)
Span Arrangement
(m)
Type of
Structure
Do Xuan Hop
Flyover
from Km2+972.4
to Km3+442.6479.2 7@[email protected]+7@30
PC Hollow
Slab
Ba Hien Bridge
Left Bridge :
from Km3+847.4
to Km3+924.8
83.7 [email protected] PC I girder
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Right Bridge :
from Km3+827.4
to Km3+904.8
1.3Major Change from Feasibility Study
Span arrangement and general issue
Name of Bridge Design Change
Do Xuan Hop
Flyover
Type of bridge was changed from Super-T girder in FS 2007 to PC HollowSlab in order to make a consideration of architectural aspects at HCMC PCrequest because the structure is located within the urban area.
HCMC requested to allow traffic to enter the expressway from Do Xuan Hopstreet without the need to go through RR2 or Nguyen Thi Dinh Street (whichwill become one-way street). In accordance with the concept, the type of DoXuan Hop intersection was designed as roundabout. And the location of pierswas designed to avoid roundabout.
For the reasons mentioned above, span arrangement was changed from 11spans (11@40m) to 16 spans (7@30m+2@25m+7@30m).
Ba Hien Bridge
Ba Hien Bridge was designed as I-girder as same as F/S.
The shape of bridge changed from squared bridge in FS 2007 to skew bridge inorder to make a consideration of direction of flow in Ba Hien River.
The structures around connection part of rampways, which are difficult toconstruct in Phase II, shall be constructed at the same time of rampwayconstruction in this Project. Therefore, according to the ramp way of RR2 ICplan in phase II, the width of bridge adapt to the one in phase II, and thewidth of left bridge become wider as the section number increase.
Detail design of structure
Name of Bridge Design Change
Do Xuan Hop
Flyover
From structure examination, pile type was changed from RC piles (40 x 40 cm)to bored piles (D=1.2m).
Footing thickness was increased from 1.5m to 2.0m.
Pier cross section was changed from rectangle to oval.
The bridge pier was designed graceful form with a curve based on aestheticstudy.
Girder height is 1.4m.
Type of bridge was changed from Super-T girder to PC Hollow Slab withchange of span length (from 40m to 30m).
Planting and foundation of slab for planting was designed between bridges ofeach direction.
Ba Hien Bridge
From structure examination, pile type was changed from RC piles (40 x 40 cm)to bored piles (D=1.2m).
Footing thickness was increased from 1.5m to 2.0m.
Pier cross section was changed from oval to circle.
Pier thickness was increased from 1.4m to 2.0m.
Girder height is 1.45m, not changed from F/S 2007.
The width of left bridge becomes wider (from 19.76m to 22.08m) as the sectionnumber increase.
MSE (Mechanically Stabilized Earth) wall was designed as retaining wall withreinforced soil wall system.
Planting and foundation of slab for planting was designed between bridges ofeach direction.
1.4Typical Cross Section
Typical cross sections of bridge are shown in following figures.
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Figure 1.4-1 Typical Cross Section of Urban Expressway (Do Xuan Hop Flyover)
Figure 1.4-2 Typical Cross Section of Urban Expressway (Ba Hien Bridge)
2.Design conditions
2.1Applied Design Standards and Specifications
Following Vietnamese standards and specifications have been applied in the bridge design.
Table 2.1-1 Applied Vietnamese Standards and Specifications
22 TCN-272-05 Specification for Bridge Design
22TCN221-95 Transport Project in area with earthquakes Design Standard
TCVN 5729-97 Expressways design specifications
TCVN 4054-2005Highways design specifications (applied for connections,collector roads)
Following international standards and specifications are also applied as reference after getting approval of the client.
Table 2.1-2 Applied International Standards and Specifications
AASHTO LRFD Bridge Design Specifications
AASHTO LRFD Bridge Construction Specifications
ASTM A 416-85 Prestressed steel for reinforcing concrete
Standard Specifications for Highway Bridges (Japan Road Association, 2002)
2.2Design Criteria
1)Load combinationThe load combination for Limit State Condition is given based on Article 3.3 of 22TCN-272-05.
Load2.
Dead Load
Applied dead load for design calculation is summarized as the following:
Table 2.2-1 Unit Weight
MaterialDensity[kN/m3 (kg/m3)]
Bituminous Wearing Surfaces 22.1 (2250)
Compacted Sand, Silt or Clay 18.9 (1925)
Concrete Plain 23.5 (2400)
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MaterialDensity[kN/m3 (kg/m3)]
Reinforced 24.5 (2500)
Loose Sand, Silt or Gravel 15.7 (1600)
Soft Clay 15.7 (1600)
Steel 77.0 (7850)
Water 9.8 (1000)
(Source: 22 TCN-272-05)
Live Load
HL-93 shall be applied as live load for the design of the bridge.
Figure 2.2-1 Design Vehicular Live Load HL-93
Other loads are applied in accordance with 22 TCN-272-05.
3)Vertical ClearanceThe vertical clearance of overpass and underpass will be decided based on the road category and discussion with the local authority.
Table 2.2-2 Vertical Clearance for Roads and Railways
CategoryVertical Clearance[m]
Remark
Other 3.20
National and Provincial Highway 4.50
Expressway 5.00 Throughway
Railway 6.00
(Source: TCVN5729:97)
4)Navigation Clearance
Navigation clearances for existing canals have been confirmed by Waterway Unit under Department of Transportation of Ho Chi Minh City,with the letter No. 745/KDS-QLKT-CL dated 22 July 2010, main contents as shown in Table 1.2.1-5:
Table 2.2-3 Navigation Clearance
No. Canal (Bridge in the Project) Required Navigation Clearance
1 Ba Cua (Do Xuan Hop Flyover) W=13, H=3m
2 Ba Hien (Ba Hien Bridge) N/A (Not planned as river traffic way)
Sseismic Design5.
Seismic effect will be considered for the bridge design and applied acceleration coefficient in this project is accordance with 22 TCN-272-05and TCXDVN 375:2006.
Zone of Maximum Seismic Intensity: Imax 6 (MSK-64)Seismic Zone 1
Acceleration Coefficient: A 0.09Table 2.2-4 Acceleration Coefficient for each Package
Package Acceleration Coefficient Location
8 0.0856, 0.0747 District 2, District 9, HCMC
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(Source: 22TCN221-95)
2.3Materials
1)Reinforcing barTable 2.3-1 Reinforcing Bar
Round bar CI
Yield strength 240MPa
Tensile strength 380MPa
Elastic modulus 200,000MPa
Deformation bar CIII
Yield strength 400MPa
Tensile strength 600MPa
Elastic modulus 200,000MPa
Source : TCVN 1651 85
Concrete2.
The following concrete classes and modulus are used.
Table 2.3-2 Concrete Class and Modules
Class Strength Modulus Structure
C50 50MPa 38,007MPa Precast girder (Super T)
C35 35MPa 31,799MPaCIP deck slab inc. link slab,Crossbeam of Super T,Hollow slab
C30 30MPa 29,440MPaAbutment, Piers Bored pile,Precast concrete plank forSuper T
C25 25MPa 26,875MPaParapet, Pedestal oflamp-post, Approach slab
C20 20MPa - Sealing concrete
C10 10MPa - Blinding concrete
Notes, Strength is based on cylinder strength (MPa)
Pre-stressing Strands2.
Table 2.3-3 Hollow slab girder
Diameter 12.7*12 strand 12.7*12 strand
ASTM A416
Location to beused
Deck slab Bottom slab
Tensile strength 1860MPa
Yield strength 1670MPa
Elastic modulus 200,000MPa
3.Bridge of Package 8
3.1Review of span arrangement
Do Xuan Hop Flyover
As for Do Xuan Hop Street, connection rampways to the urban expressway was requested to design. In accordance with the concept, the type ofDo Xuan Hop intersection was designed as roundabout. And the location of piers was designed to avoid roundabout. According to thismodification, bridge pier arrangement has been carefully decided so that there will be neither re-arrangement nor interfering of structures in PhaseII. In consideration of urban landscaping, bridge type has been changed to hollow slab girder from Super-T girder.
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Table 3.1-1Comparison in Pier Location of Do Xuan Hop Flyover
Table 3.1-2Comparison in Pier Location of Do Xuan Hop Flyover
No.1 Basic Plan (Round shaped) No. 2 Alternative Plan (Ellipse shaped)
Profile&Plan
Shape of pier changed from squareto circle for not invadingroundabout.
Two pier locations are close toroundabout.
Piers of elevation are crowded.
Crossing length is short.
Shape of pier is square.
Piers locate apart fromroundabout.
Pier location of both up and downroad matches.
Crossing length is more 40m.
Figure 3.1-1Span arrangement of F/S
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Figure 3.1-2Improved span arrangement in D/DBa Hien Bridge
Ba Hien Bridge was designed as I-girder as same as F/S. Widening by RR2 Interchange rampway is in the bridge location and bridge width is aswide as 19.75 - 22.08 m and two (2) piers are installed in one (1) foundation. In consideration of the river flow, the bridge angle is set to skew tokeep a river width of 10m and make the bridge pier shape with circle section.
Figure 3.1-3Span arrangement of F/S
Figure 3.1-41Improved span arrangement of D/D3.2Substructure
Design of pier cap and column1.
Pier shape is rectangler section in a general part. Pier shape are shown below.
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Bridge Shape of pier
Do Xuan Flyover Oval
Ba Hien Bridge Circle
Figure 3.2-1Pier shape of Do Xuan Flyover
Figure 3.2-2Pier shape of Ba Hien bridge
Table 3.2-1Shape of pier
Design results of pier cap and column are shown in following tables.
Table 3.2-2Do Xuan Hop Flyover
Table 3.2-3Ba Hien Bridge
2)Design of pile
The kind of pile is applied bored pile to the bridges. Soil condition of two bridges has thin hard layer, if driven pile is applied, there is possibilitythat drive is impossible by intermediate hard layer. Therefore, bored pile is selected.
Pile type and pile number of bridges of Package 8 are shown in the following table.
Table 3.2-4Pile type and pile number of Package 8 bridge
Bridge Pile type D Number of pile (/pier)
Abutment Pier
Do Xuan HopFlyover
Bored pile D1.2 6,8 5,6
Ba Hien Bridge Bored pile D1.2 8 8
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Design results of pile are shown in following tables.
Table 3.2-5Do Xuan Hop Flyover
Item EL2
Length Number Force Capacity
Safy
of pile of pile (KN) (KN)
A1 -2.00 61.00 2X8 4472.00 4578.69 1.02
P1, P2 -2.00 71.00 2X5 4495.00 4585.78 1.02
P3 -2.00 71.00 2X5 3825.00 4016.20 1.05
P4, P5 -2.00 81.50 2X5 3825.00 3858.21 1.01
P6 -2.00 61.00 2X5 4840.00 5030.01 1.04
P7 -2.00 61.00 2X5 4840.00 4846.35 1.00
P8 -2.00 61.00 2X5 4328.00 4475.84 1.03
P9 -2.00 66.00 2X5 4840.00 4845.06 1.00
P10 -2.00 71.00 2X5 4840.00 5889.78 1.22
P11 -2.00 66.00 2X5 4495.00 4585.78 1.02
P12 -2.00 66.00 2X5 4495.00 4527.16 1.01
P13 -2.00 66.00 2X5 4495.00 4531.37 1.01
P14,P15 -2.00 61.00 2X5 4495.00 4585.78 1.02
A2 -2.00 66.00 2X8 4224.00 4253.00 1.01
Table 3.2-6Ba Hien Bridge
Item EL2
Length Number Force Capacity
Safy
of pile of pile (KN) (KN)
A1L -1.50 69.00 8.00 5054.00 5900.00 1.17
P1L -1.00 69.00 8.00 3664.20 5895.00 1.61
P2L -3.00 69.00 8.00 3720.60 4886.00 1.31
A2L -1.50 73.00 10.00 4401.20 5271.00 1.20
A1R -1.50 71.00 8.00 4129.99 4995.00 1.21
P1R -3.00 69.00 8.00 3341.80 5010.00 1.50
P2R -3.00 69.00 8.00 2996.60 5010.00 1.67
A2R -1.50 71.00 8.00 4205.80 6124.00 1.46
Design result
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Figure 3.2-3Bored Pile D=1.2m
3.3Superstructure of hollow slab girder
Span arrangement and structure type1.
a. Structural properties
Continuous Deck (W=12.25 m, including railing)
b. Girder Arrangement
Girder arrangement of Do Xuan Hop Flyover is 7@[email protected]+7@30 m continuous hollow slab girder. The general view of bridge is shownin Figure.
Continuous span length is determined to fill the conditions of construction period and deflection did not become excessive. Assumedconstruction schedule of Package 8 is shown in a figure. In order to complete Do Xuan Hop flyover within construction period of 24-27month,it is necessary to divide into two bridges of 8span, and it needs to construct superstructure simultaneously by 4 parties. In the design,construction joint and jack space is prepared in consideration of this construction process.
Figure 3.3-1Construction Schedule of Package 8
Figure 3.3-2General view of hollow slab bridge
Design of girder2.
a.Member DimensionGirder shape is shown below.
Figure 3.3-3Typical Cross Section of Hollow slab Girderb.Tendon Arrangement
Tendon arrangement of Do Xuan Hop Flyover.
Tendon arrangement of Hollow salb girder is shown below. 23 internal cable of 12.7mm are arranged in web. Tendon is arranged . Tendonarrangement at major section is shown below.
Figure 3.3-4Tendon arrangement of Do Xuan Hop Flyover
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Figure 3.3-5Tendon arrangement of typical section
Design result of girder3.
In analysis, a structure condition is changed and construction schedule is reflected in presumption of creep and shrinkage according toconstruction schedule. Construction sequence taken into consideration in analysis is shown in a figure. And Check results of stress in servicelimit state of Hollow slab girder are shown bellow.
Figure 3.3-6Construction sequence
Figure 3.3-7Concrete Stress of deck slab at Service
Figure 3.3-8Concrete Stress of bottom flange at Service Limit stateThe result of the bending resistance of Strength limit state is shown in the followingfigure.
Figure 3.3-9Result of checking of bending resistance at M-Max and M-Min
4.
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Bearing
a.Rubber BearingThe girder is fixed by rubber bearing at abutment and centre pier. In Do Xuan Hop Flyover, longitudinal displacement is not large and rubberbearing can distribute reaction force of super structure for each pier. Elastic bearing is chose from above reason and durability and cost.
Figure 3.3-1Notes; Anchor bar is installed with rubber bearing for longitudinal unexpected earthquake and transverse movement
0Bearing Arrangement
Figure 3.3-11Rubber Bearing
3.4Superstructure of I girder
Girder arrangement and structure type1.
a.Structural propertiesDiscontinuous Deck ( W=19.75m for right bridge , and from 19.760m to 22.08m for left bridge)
b.Girder ArrangementOne span consists of 8 I girders for right bridge, 9 I girders for left bridge . The typical cross section is shown in Figure.
Figure 3.4-1Typical Cross Section of Viaduct
Design of girder2.
a.Member DimensionGirder shape of I girder for 25.7m span is shown below.
General section Cross beam section
Figure 3.4-2Typical Cross Section of I Girder (Lc=25.7m)b.Tendon Arrangement
Arrangement of I Girder is shown below. 5 strands are arranged for a girder.
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Figure 3.4-3Tendon Arrangement of I Girder (L=25.7m)
Bearing3.
Rubber bearing is adopted due to durability and economical reason. The bearing is widely used for this type of bridge. Above eachintermediate pier, slab is connected with link slab and roadability is improved.
Figure 3.4-4Bearing Arrangement
Figure 3.4-5Rubber Bearing
Expansion Joint4.
A finger type joint is applied for super I-girder.
Figure 3.4-6Type Expansion Joint
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