CABLE STAYED BRIDGE AT BARDHAMAN
DESIGN SIMULATION BY LARSA AND
CONSTRUCTION STAGE ANALYSIS ALONGWITH GEOMETRY CONTROL BY LUSAS
Rajesh Prasad,Chief Project Manager M,RVNL Kolkata
Construction stage analysis of Cable Stayed Bridge with total length 188.431 m for ROB at Bardhaman Yard is presented here. The superstructure carries 7.5m carriageway and 1.5 m wide footpath on each side.
DECK Geometry:Total Length of the Bridge : 188.431 mCP1 to P1 (Steel composite deck) : 124.163 mP1 to CP2 (RCC Deck) : 64.265 mNumber of Lanes in each Direction : 2Width of bridge deck for main span : 27.7 mWidth of bridge deck for back span : 28.2 mFootpath : 1.5 m on both sidesCross Slope : 2 %
INTRODUCTION
GENERAL ARRANGEMENT
Plan & Elevation of the Bridge
GENERAL ARRANGEMENT
Cross section of the pylon
GENERAL ARRANGEMENT
Cross section of Main Span
Cross section of Back Span
In Lara4D we have simulated this construction stages so as to get more realistic analysis. As cable elements have been used which are nonlinear in nature, nonlinear analysis has been carried out at each stage.
In Larsa4D, for steel we provided following material property:
• E = 2 x108 KN/m2
• Density = 7850 Kg/m
• Shear Modulus = 7.88 x107 KN/m2
• Poisson Ratio = 0.3
Transverse section showing components of Back Span (64.266m)
65mm WEARING COAT
Transverse section showing components of Back Span (124.163m)
65mm WEARING COAT
In Larsa 4D these construction stages are simulated so as to get more realistic analysis. As cable elements have been used which are nonlinear in nature, nonlinear analysis is carried out at each stage. The initial structure has been kept with a pre-camber such that after complete construction, the deflection brings the structure to desired finish level.
Fundamental period of vibration of the structure is calculated by creating a 3D model of the structure and carrying out its modal analysis in STAAD Pro V8i/ Midas Civil/ Larsa4D.
Stage 16•Max moment in Pylon. Utilization ratio <1
Bending Moment diagram (Dead Load + SIDL)
Stage 16•Max moment in Pylon. Utilization ratio <1 Max. deflection is 208 mm (with
lane reduction it will become 166mm)
Bending Moment diagram (Two Tracks of 70R wheeled)
NATURAL VIBRATIONAL MODE SHAPE-2 (FREQUENCY = 0.66HZ & T = 1.520 SEC)
Analysis Model
• Analysis has been done using finite element analysis software
LUSAS.
• Deck is modeled as grillage of longitudinal and transverse members.
• Deck is integral at P1 and CP2. At CP1 pin support with longitudinal
free movement is used representing the Guided PTFE bearings.
• At P1 and CP2, elastic spring supports representing the pile
stiffness are used.
CABLES
PYLON
PILECAP AND PILE
TEMPORARY SUPPORTS
PIN SUPPORT
LUSAS model of the Bridge
Analysis Model
Grillage of Main Span
Grillage of Back Span
Analysis Model
• Transverse beams are modeled with steel composite properties.
• RCC girders and slabs are modeled as beam elements with
appropriate width and depth as per their spacings.
Analysis Model
• At pylon location and at the end on anchor span deck is integrated with
substructure. So the substructure is also modeled as part of grillage.
• The wall is divided in to longitudinal (vertical) and transverse members.
• The pile cap is modeled along with spring supports with the stiffness of
piles.
• Pylon is represented using beam elements.
• Cables are modeled as 3D-bar elements which exhibits the axial
stiffness in all the three orthogonal directions.
Analysis Model
Analysis Model
Isometric View of the model
Analysis Model
Rendered View of the model
SECTION PROPERTIES
Sr no Component C/S Aream2
M.I. Y-Ym4
M.I. Z-Zm4
1 Longitudinal beam MG1 0.1985 0.06506 0.02084
2 Longitudinal beam MG2 0.20134 0.11369 0.05244
3 Central pylon PL1 0.44 0.41537 0.29487
4 Side pylon PL2 0.3536 0.33657 0.23929
5 Tie Beam 0.0975 0.01546 0.01546
6 RCC side beam 4.5 2.34375 1.215
7 RCC central beam 5 2.60417 1.66667
SECTION PROPERTIES
Sr no Component C/S Aream2
M.I. Y-Ym4
M.I. Z-Zm4
8 Steel cross girder with 4.0m wide deck-End 1 0.20611 0.01292 0.00742
Steel cross girder with 4.0m wide deck-End 2 0.1614 0.0073 0.00572
9 Steel cross girder with 3.5m wide deck-End 1 0.18424 0.01264 0.00507
Steel cross girder with 3.5m wide deck-End 2 0.14478 0.00714 0.00393
10 Steel cross girder with 3.0m wide deck-End 1 0.16236 0.01231 0.0033
Steel cross girder with 3.0m wide deck-End 2 0.12815 0.00696 0.00258
11 Steel cross girder with 2.08m wide deck-End 1 0.12218 0.0115 0.0013
Steel cross girder with 2.08m wide deck-End 2 0.09761 0.00649 0.00106
12 Steel cross girder with 1.58m wide deck-End 1 0.1003 0.01086 0.00073
Steel cross girder with 1.58m wide deck-End 2 0.08099 0.00611 0.00063
Cable No
No of Strands
C/s Area (Sq.m)
6001 22 0.0033
6002 22 0.0033
6003 22 0.0033
6004 22 0.0033
6005 22 0.0033
6006 22 0.0033
6007 31 0.0047
6008 31 0.0047
6009 31 0.0047
6010 31 0.0047
6011 31 0.0047
6012 31 0.0047
6013 31 0.0047
6014 31 0.0047
6015 31 0.0047
6016 31 0.0047
6017 31 0.0047
6018 31 0.0047
SECTION PROPERTIESCable
NoNo of
StrandsC/s Area (Sq.m)
7001 73 0.011
7002 73 0.011
7003 73 0.011
7004 61 0.0092
7005 61 0.0092
7006 61 0.0092
7007 61 0.0092
7008 61 0.0092
7009 61 0.0092
7010 85 0.0128
7011 85 0.0128
7012 73 0.011
7013 73 0.011
7014 73 0.011
7015 73 0.011
7016 73 0.011
7017 73 0.011
7018 73 0.011
MATERIAL PROPERTIES - concrete
• CEB-FIP Model 1990 which is widely acceptable and available in LUSAS
is used to represent the concrete properties with age effect .
• Compressive strength of concrete varies with time is represented as
• fcm(t) = fcm exp(s(1-(28/t)^0.5))
• In above, assumed s = 0.25 (FOR NORMAL CEMENT CONCRETE )
• Concrete strength required is 50MPa (cube) = 40 MPa (cylindrical).
• Ec = 2.15E4 x (fcm/10)(1/3) = 34129000 kN/m2.
MATERIAL PROPERTIES - concrete
• Young’s modulus = 34129000 kN/m2.
• Poison ratio = 0.15
• Density = 2.548 t/m3
• Coefficient of thermal expansion = 0.000012
• Comp. strength = 40000 kN/m2.
• Relative humidity = 70%
• Nominal size = 2Ac/U
MATERIAL PROPERTIES – steel
• Young’s modulus = 200000000 kN/m2.
• Poison ratio = 0.3
• Density = 7.85 t/m3.
• Coefficient of thermal expansion= 0.000012
SUPPORT CONDITION
• Pylon P1 and Pier CP2 are modelled as pilecap with spring
supports of having stiffness of pile.
• At pier CP1, pin support is assumed at bearing level. So only
vertical and transverse translations are restrained and other
displacements are allowed to be free.
• Temporary supports with their corresponding stiffnesses are
assigned to rear concrete deck. These supports are modelled
as "Compression only" spring supports and will be ineffective
when the deck lifts off.
LOADINGS
• Self weight of decks is applied as body force to longitudinal
members, and the weight of cross girder is applied as UDL on
corresponding member.
• The weight of steel stiffeners, diaphragms are precisely considered
and their respective loading locations are used. To account the
weight of evenly distributed stiffeners/studs, material density is
modified appropriately.
• The following table and figure shows a typical 12m segment of
main girder along with the DL considered.
LOADINGS
DL considerations for MG2:
DL considerations for MG1:
SR. Pylon Total WT Consideration forNO. (kN) Model
1 PL1 3115 Density Modified to 13.23 T/m3
2 PL2 5070 Density Modified to 13.34 T/m3
• The weight of pylon segments are also considered according to
the detail drawings by appropriately modifying material density.
DL considerations for Pylon:
• The self weight of DEC
considered for analysis is
applied as four point loads.
To account for the weight of
rails etc., the weight of DEC
has been increased
accordingly (7.6% for front
and rear support and 25.4 %
for CW trolley). Hence the
total weight of DEC
considered is 1806 kN.
DL considerations for Deck Erection Crane (DEC):
• To account for the weight of cable installation equipments and
strand coils, an additional 24T is considered as below.
DL considerations for Cable Installation Equipments & Strand coils etc:
• For each of the six material trolley rails, 1kN/m load is assumed.
SIDL Consideration
• Referring to CES Design report, Following SIDL has been considered.– For crash barrier:1.946 kN/m2 (Applied to total width of
25.7 m)– For wearing coat: 1.43 kN/m2 (Applied to total carriage way
width)
Construction stages
• Load case 1 : Casting of RCC wall at P1 and CP2 is considered to be complete.
• Load case 2 : Casting of RCC beam & slab between P1 and CP1.(DL is assigned. )
• Load case 3 : Erection of steel pylon. (Gravity is assigned to erected pylon )• Load case 4 : Activation and stressing of Backspan cables 6010 & 7010• Load case 5 : Erection of 1st panel.• Load case 6 : Activation and stressing of cables 6009, 7009.• Load case 7 : Panel 1 Green Concrete Load (DL is applied as UDL on CG)• Load case 8 : Activation of Deck on 1st panel.• Load case 9 : Erection of DEC.
Construction stages
• Load case 10 : Activation and stressing of Back span cables 6011 & 7011• Load case 11 : DEC moved for 2nd panel.• Load case 12 : Erection of 2nd panel.• Load case 13 : Activation and stressing of cables 6008, 7008.• Load case 14 : Panel 2 Green Concrete Load (DL is applied as UDL on CG)• Load case 15 : Activation of Deck on 2nd panel.• Load cases16 to 62: Load cases 10 to 15 described above are repeated in
sequence for erection of panel 3 onwards till completion of the entire deck i.e panel 10.
• Load case 62 : Activation of Deck on 10th panel.• Load case 63 : Remove DEC• Load case 64 : Crash Barrier load is applied.• Load case 65 : Second Stage Stressing• Load case 66 : Temporary back span supports removed• Load case 67 : Wearing Coat load is applied.
Analysis and Design checks
• Considering the above stages, analysis has been carried out. Analysis steps have been described in detail in our design note No 8160/E/DN-01-R2.
• Design forces and the stress checks are presented in our design Note no 8160/E/DN-03-R1.
• Theoretical profile of the deck is presented in drawing no 8161/E/DD-02 to 13.
• Few suggestions are received from DDC and are incorporated in the analysis. The revised details and the entire set of the camber drawings will be submitted shortly.
DEFLECTION COMPARISON SL. No. Description of stage Actual Stage
Deflection
Theorotical Stage
Deflection
SL. No. Description of stage Actual Stage Deflection
Theorotical Stage
Deflection1 After Stressing MS-1 6 After casting slab 6009 46 26.95 6009 -28 -15.45 5009 37 42.41 5009 -13 -15.40 7009 49 29.37 7009 -29 -18.312 After casting slab 6008 -55 -45.72 6009 -13 -12.77 5008 -55 -45.93 5009 -14 -12.88 7008 -62 -52.64 7009 -20 -16.30 7 Stressing of BS-3 3 Stressing of BS-2 6009 14 11.67 6009 7 5.92 5009 5 11.69 5009 5 5.81 7009 7 11.50 7009 8 5.00 6008 24 29.864 Erection of panel-2 5008 23 29.91 6009 -40 -28.29 7008 23 30.25 5009 -28 -28.48 8 Restressing of 5008 7009 -37 -27.61 6009 -2 -4.875 Stressing of MS-2 5009 25 23.49 6009 27 30.32 7009 11 5.82 5009 13 30.48 6008 -8 -6.54 7009 27 31.39 5008 83 82.09 6008 142 109.97 7008 22 18.95 5008 136 110.23 9 Erection of panel-3 7008 123 107.92 6009 -35 -30.37
5009 -21 -30.95 7009 -33 -33.92 6008 -96 -111.70 5008 -98 -113.10 7008 -104 -115.71
SURVEY REPORT FORMAT
2 MILLION CYCLE FATIGUE TEST
COMPLETION OF 2 MILLION CYCLE FATIGUE TEST ON 12.05.2014
TENSILE LOAD TEST OF THE STRAND AFTER 2 MILLION CYCLES
1
1
COMMENCEMENT OF FATIGUE TEST SECOND STRAND ON 13.05.2014
44
INSPECTION OF ANCHORAGES
45
CHECKING HARDNESS OF WEDGES
46
ROTATIVE FLEXION TEST (12.05.2014)
47
Trial of Girders at site
Trial of DEC at Fabrication yard
Trolley loaded with Girders/slabs
USFD Checking of Track over Deck
Pylon And Deck Erection For Barddhaman Cable
Stayed ROB
Rail Vikas Nigam Limited
• Pylon erected with High Capacity Tower Crane
• Steel Girders of Composite Deck to be erected with Deck Erection Crane
PYLON SEGMENTS ERECTION WITH TOWER CRANE
ERECTION OF PYLON SEGMENTS
The Team
Placement of Middle girder
Placement of 2 end girder
Placement of 2 cross girder
Placement of 2 more girder (power/traffic block)
Placement of 2 more cross girder (power/traffic block)
Special arrangement of temporary P/F for tightening of HSFG bolts.
Tightening , Checking of HSFG bolts followed by painting at site.
View after placements of all girders for panel no. 3 over track.
View after placements of all girders for panel no. 3 over track.
Placements of Cables, Slabs, Casting deck
Placements of Cables, Slabs, Casting deck
View after placements of all Precast Slab for panel no. 2 over track.
Installation of strand
Survey Reports (Cable 5011)
• HDPE Ducts Preparation• Corrected Table for Temperature• HDPE Duct Welding Table Instructions• Master Strand Preparation Form• Standard Strand Setting Form• Master Strand Setting Form• Isotension Statement• Cable Force Measurement• Anchorage Gird – Under Deck/Outside Pylon• Anchorage Grid – Inside Pylon/Over Deck
Power/Traffic Block Requirement
1/2
Power/Traffic Block Requirement
2/2