a case study-delhi metro phase iii - balanced cantilever bridge

8/15/2019 A Case Study-Delhi Metro Phase III - Balanced Cantilever Bridge

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A Case Study on Balanced CantileverBridges – Delhi Metro Phase III

Piyush Santhalia – Project Engineer


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Case StudiesSl.No

SpanArrangement (m)

Project Client Contractor Status

1 34 + 60 + 34 CC28Delhi Metro –Phase III, Line 7

DelhiMetro

L&T Completed

2 60 + 60 CC28Delhi Metro –Phase III, Line 7

L&T Super-structurepartlycompleted

3 37 + 69 + 67 + 55

+ 34

CC26R

Delhi Metro –

Phase III, Line 7

ITD Foundation

and Sub-structurecompleted


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CC28 – Balanced Cantilever Bridge

i) 34 + 60 + 34 m ii) 60 + 60 m


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CC28 – Balanced Cantilever BridgeI. 34 + 60 + 34 m

II. 60 + 60 m


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CC28 – Balanced Cantilever BridgeI. 34m + 60m + 34mStructure Type : Cast-in-Situ PSC Box Girder


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CC28 – Balanced Cantilever BridgeI. 34 + 60 + 34m Span - General Arrangement


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CC28 – Balanced Cantilever BridgeI. 34 + 60 + 34 Cross Sections

Overall Width of Deck = 8.844 m

Depth of the Box Girder: Varies from 5m at intermediate Piers to 2.1m at Mid-Span

Area (m 2) 8.890

Iyy (m 4) 28.79

Area (m 2) 4.980

Iyy (m 4) 2.63


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CC28 – Balanced Cantilever BridgeI. 34 + 60 + 34 Foundation & Sub - structure

Intermediate Piers P122 and P123 are integral Piers.

Twin Piers, each leaf of dimension 1000 X 3400 mm

Free Bearings at P121 and P124.

Circular Piers with 2100 mm diameter

Pile Foundation

1000 mm dia. , cast-in-situ bored piles.


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CC28 – Balanced Cantilever BridgeI. 34 + 60 + 34 Construction Sequence


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CC28 – Balanced Cantilever BridgeI. 34 + 60 + 34 Construction Sequence contd…


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Casting of Segment S8 (one just before stitch segment)


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Casting of Stitch Segment


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CC28 – Balanced Cantilever BridgeI. 34 + 60 + 34 Analysis & Design

- Midas Civil has been used for numerical modelling and Structural Analysis

- Super Structure (Box Girder) Piers and Piles have been modelled as Line Element

- Pile Cap has been modelled as plate element.

- Point Spring Supports to take the effect of soil.


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- Concrete has been modelled with time dependent properties in Midas Civil

- Creep and Shrinkage and compressive strength gain behaviour has been defined as

per CEB-FIP


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- Internal Prestressing

- 19T15 and 12T15 anchorages

http://localhost/var/www/apps/conversion/tmp/scratch_3/AECOM-CC-28-NN-13001-PRESTRESSING_R3%20(Sh%201%20to%208).pdfhttp://localhost/var/www/apps/conversion/tmp/scratch_3/AECOM-CC-28-NN-13001-PRESTRESSING_R3%20(Sh%201%20to%208).pdf


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- Simulation of exact Construction Sequence in Midas.

- Able to check stresses at intermediate steps in all construction stages.


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- Maximum Stress (Tension) at top Fibre Envelope (during construction)

- Maximum Compression at Top Fibre Envelope (during construction)


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- Maximum Tension at Bottom Fibre Envelope (during construction)

- Effect of stressing Tendons one by one


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- Results: Stress Check for Service Loads: Normal Case

Stresses at Top Fibre due to Combination G I (N/mm 2)

Stresses at Bottom Fibre due to Combination G I (N/mm2)


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- Pre-camber: Day of commissioning as the critical day

- Precision: Only 6mm of difference between the theoretical value and theobserved value of deflection at the cantilever tips, just before stitching.


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- Deformation, including the effect of creep after 120 years

Deformation due to Normal Case – after 120 years (mm)


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CC28 – Balanced Cantilever BridgeII. 60m + 60m

Structure Type : Cast-in-Situ PSC Box Girder


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CC28 – Balanced Cantilever BridgeII. 60 + 60m Span - General Arrangement


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CC28 – Balanced Cantilever BridgeII. 60 + 60m Foundation & Sub - structure

Intermediate Piers P217 is integral Piers.

2300mm Diameter circular Pier

Free Bearings at P216 & P218.

Circular Piers with 2100 mm diameter

Pile Foundation

1000 mm dia. , cast-in-situ bored piles.


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CC28 – Balanced Cantilever BridgeII. 60 + 60m Analysis & Design

- Midas Civil has been used for numerical modelling and Structural Analysis

- Super Structure (Box Girder) Piers and Piles have been modelled as Line Element

- Pile Cap has been modelled as plate element.

- Point Spring Supports to take the effect of soil.


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CC28 – Balanced Cantilever BridgeII. 60 + 60m Construction Sequence contd…


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CC28 – Balanced Cantilever BridgeII. 60 + 60m Construction Sequence contd…


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- Maximum Stress (Tension) at Top Fibre Envelope (during construction)

- Maximum Compression at Top Fibre Envelope (during construction)

Sign Convention: +ve Value of Stresses denote Tension-ve Values denote compression


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- Maximum Tension at Bottom Fibre Envelope (during construction)

- Maximum Compression at Bottom Fibre Envelope (during construction)



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- Results: Stress Check for Service Loads: Normal Case

Stresses at Top Fibre due to Combination G I (N/mm2)

Stresses at Bottom Fibre due to Combination G I (N/mm2 )



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- Pre-camber: Day of commissioning as the critical day


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- Deformation, including the effect of creep after 120 years

Deformation due to Normal Case – after 120 years (mm)


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CC26R – Balanced Cantilever BridgeI. 37 + 69.9 + 67 + 55 + 34m Span - General Arrangement


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CC26R – Balanced Cantilever BridgeI. 37 + 69.9 + 67 + 55 + 34m Cross SectionsOverall Width of Deck = 8.844 m

Depth of the Box Girder: Varies from 4.7m at intermediate Piers to 2.8m at Mid-Span

Area (m 2) 10.01

Iyy (m 4) 28.73

Area (m 2) 5.90

Iyy (m 4) 6.13


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CC26R – Balanced Cantilever BridgeI. 37 + 69.9 + 67 + 55 + 34m Construction Sequence

Intermediate PiersP235: Free Pier

P236: Integral PierP237: Integral PierP238: Free Pier


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CC26R – Balanced Cantilever Bridge

I. 37 + 69.9 + 67 + 55 + 34m Construction Sequence contd…

Stresses at Top Fibre due to DL + PS + CR + SH (N/mm2)


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Stresses at Bottom Fibre due to DL + PS + CR + SH (N/mm2)


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I. 37 + 69.9 + 67 + 55 + 34m Foundation & Sub - structurePile Arrangement at P236

Intermediate PiersP235: Free PierP236: Integral Pier

P237: Integral PierP238: Free Pier


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I. 37 + 69.9 + 67 + 55 + 34m Foundation & Sub - structurePile Arrangement at P237

Intermediate PiersP235: Free PierP236: Integral Pier

P237: Integral PierP238: Free Pier


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I. 37 + 69.9 + 67 + 55 + 34m Analysis & Design




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I. 37 + 69.9 + 67 + 55 + 34m Analysis & DesignStress Check for Service Loads: Normal Case


Stresses at Top Fibre due to Combination G I (N/mm 2)

Stresses at Bottom Fibre due to Combination G I (N/mm 2)


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Thank You

a case study-delhi metro phase iii - balanced cantilever bridge

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