Dubai Metro Project Viaduct Superstructure – Calculations … · 2011. 7. 4. · DUBAI RAPID LINK...

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WS Atkins & Partners Overseas

Dubai Metro Project

Viaduct Superstructure – Calculations

Storage & Stacking of Standard Twin Track Segments

Submission of Calculations

July 2006

Dubai Metro Project – Viaduct Superstructure CalculationStorage & Stacking of Standard Twin Track Segments

WS ATKINS & PARTNERS OVERSEAS

Date: 03 July 2006Document No.: DM001-E-ACW-CVI-DR-DCC-318020

Rev: A1

Client:

JT Metro JV

Contract No. (if any):

Project Title:

Dubai Metro, UAEProject No.:

JRD4561

Document No.:

DM001-E-ACW-CVI-DR-DCC-318020 Controlled Copy No.:

Document Title:

Viaducts Superstructure – Calculations

Storage & Stacking of Standard Twin Track Segments

Covering Letter / Transmittal Ref. No.: Date of Issue:

03 July 2006

Revision, Review and Approval/Authorization Records

01 Issue to JVNigel Hewson03 July 2006

J. SundaramJuly 2006

Bruce ManeyJuly 2006

Revision DescriptionPrepared by /

dateReviewed by /

dateApp. or Auth.

by / date

Distribution (if insufficient space, please use separate paper)

Controlled Copy No. Issued to

1 JT Metro JV

2 Atkins (Office Copy)

Note: App. and Auth. mean “Approved” and “Authorized” respectively.

CONTENTS

1. INTRODUCTION ............................................................................................................ 2

2. DESIGN CHECK............................................................................................................. 2

3. RESULTS........................................................................................................................ 3

4. CONCLUSIONS.............................................................................................................. 4

APPENDICES

A. Layer storage of the segments

B. Segment stacking calcs carried out by Atkins (Dubai)

C. FE Models used in analysis and output of results

D. 20m span FE model deflections – for comparison

1. INTRODUCTION

The attached report provides the flexural stresses and permanent deformations in

the segments, for single-level stacking and for double stacking.

This report has to be read together with “Segment Stacking.pdf” previous

submitted and included in appendix B.

2. DESIGN CHECK

A FE analysis of the segments has been carried out in order to check the flexural

stresses and the permanent deformations.

Two different models have been analysed; the first model took into account a

typical mid-span segment of the simple span, the second one a typical pier

segment of the simple span. These models are shown in appendix B.

The disposition of the supports was in accordance with the sketches in the

“Segment Stacking.pdf” report, included in appendix A.

For each model two load-cases have been analysed:

Self-weight only (single level stacking)

Self-weight + concentrated loads due to the double stacking.

Appendix C shows the typical location of the supports and concentrated load

applied into the models.

The analysis has been carried out considering:

Concrete grade 30MPa

Concrete Unit weight 24.5kN/m3

Reinforcement yield strength 460MPa

Nominal cover to reinforcement 40mm

36m straight span cross sections

Thick shell surface mesh

Once obtained the stress and force distributions from Lusas then the values have

been compared with the BS5400 Part 4 stress limitation:

SLS

Reinforced concrete 0.5 fcu = 0.5 x 30MPa = 15MPa (compression)

0.56 fcu = 3.07Mpa (Tension)

Reinforcement 0.75 fy = 345MPa

Also, a bending moment capacity and crack check for the slab has been done

using SamLeap5 in order to check the maximum bending moments in the slab

obtained from the FE analysis.

The permanent deformations have been compared to those obtained for the 20, 28,

32 and 36m straight span analysis, and found to be similar. The plot of deflections

for the 20m span is given in appendix D.

3. RESULTS

See results in appendix C.

i) Deflections – single segment storage

Maximum deflections – 6.9mm in middle of slab for mid-span segment,

– 1.2mm in middle of slab for pier segment.

This is a short term deflection based on short term “E” value.

The segments could be stored for a 2 or 3 months and during this time it is

unlikely that more than 20% of the creep will occur, giving creep movements

approximately 1.5mm. All the stored field segments should creep a similar

amount and when erected this should not be a problem.

The pier segment deflection at the middle of the slab is approximately 5mm less

than the adjacent field segments. This is not a problem in the storage of the

segments but the joint may need to be aligned during the erection to match the

shear keys.

ii) Deflections – double stacking of segments

As the supports of the upper segment are always directly above the supports of the

lower segment then no additional deformations should be imposed on the lower

segment.

The analysis shows a slightly different deflection between the single stored

segment and the double stacked segments, and this is caused by the

approximations and simplifications for the supports and applied load.

iii) Stresses

The stresses set up in the segments due to storing a single segment or double

stacking are shown in the plots in appendix C.

These stresses are catered for in the bending and shear check and design.

iv) ULS shear check

Refer to previous calcs in appendix B.

v) Bending check

Transversely, the bending moments are similar to the dead load moments set up in

the permanent structure and the reinforcement provided will be adequate.

Along the edge-beams, the longitudinal tensile stresses generating from bending

will need to be catered for by the reinforcement present.

Considering the tensile stresses, maximum total tension force at the top of the

edge beam (hogging over the single support) the total tension force = 17.1 kN

(stress x area from stress plots) SLS

To limit crack widths, the stress in the reinforcement at SLS will be limited to 200

N/mm2.

Therefore required area of reinforcement = (17.1 x 103)/200 = 85.3mm

2

Considering tension in bottom of the edge beam (sagging between double

supports) the total tension force = 6.2 kN

Therefore required area of reinforcement = (6.2 x 103)/200 = 31mm

2

And considering only 2T12 (Area= 226.2mm2) as the minimum longitudinal bars

provided along the webs, the check is satisfactory.

4. CONCLUSIONS

The checks carried out suggest that the stacking arrangements as shown under

RFI No.: CIVIL/CS-RFI-112-06 is found to be acceptable based on a minimum

strength of 30MPa.

APPENDIX A

Layer storage of the segments

DE ECCHERRIZZANI

DUBAI METRO PROJECT

SUPERSTRUCTURE WORKS

APPENDIX B

Segment stacking calcs carried out by Atkins (Dubai)

APPENDIX C

FE Models used in analysis and output of results

APPENDIX D

20m span FE model deflections (for comparison)

Dubai Metro Project Viaduct Superstructure – Calculations … · 2011. 7. 4. · DUBAI RAPID LINK...

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