TRU, Alm.del - 2021-22 - Bilag 97: Orientering om tredjepartsvurdering af tidsplanen for byggeriet af den nye Storstrømsbro, fra transportministeren

Transportudvalget 2021-22
TRU Alm.del Bilag 97
Offentligt

25 OCTOBER 2021

DANISH ROAD DIRECTORATE

STORSTRØM BRIDGE

INVESTIGATION REPORT

WORK PLAN AND TIME SCHEDULE FOR DESIGN & CONSTRUCTION

TRU, Alm.del - 2021-22 - Bilag 97: Orientering om tredjepartsvurdering af tidsplanen for byggeriet af den nye Storstrømsbro, fra transportministeren TRU, Alm.del - 2021-22 - Bilag 97: Orientering om tredjepartsvurdering af tidsplanen for byggeriet af den nye Storstrømsbro, fra transportministeren

ADDRESS

COWI North America Ltd.

138 13th Street East,

Suite 400

North Vancouver, BC

V7L 0E5

Canada

TEL

FAX

WWW

+1 604 986 1222

+1 604 986 1302

cowi-na.com

25 OCTOBER 2021

DANISH ROAD DIRECTORATE

STORSTRØM BRIDGE

INVESTIGATION REPORT

WORK PLAN AND TIME SCHEDULE FOR DESIGN & CONSTRUCTION

PROJECT NO.

DOCUMENT NO.

PREPARED

REVIEWED

A047030

VERSION

A047030-COWI-RPT-001-0

DATE OF ISSUE

DESCRIPTION

Nedim Alca

James Campbell

APPROVED

25 October 2021

Final Report

Peter Reinholdt

STORSTRØM BRIDGE

INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

EXECUTIVE SUMMARY

A 4 km long combined road and rail bridge, Storstrøm Bridge, is being constructed between

the islands of Sjælland and Falster. It is being built under a Design and Build Contract by

Storstrøm Bridge Joint Venture (SBJV) for the Danish Road Directorate (DRD). The Contract

was signed in early 2018, but the Project has suffered significant delays.

COWI North America Ltd. (COWI) was requested by the DRD to provide an unbiased

assessment of the time schedule, on which the DRD has based their estimated timing for

opening of the new bridge to road traffic and have it ready for installing catenary system

for railway by second half of year 2024, and to advise on possible actions which could be

taken to improve speed of construction and reliability of predictions.

In this study, the overall construction programme was reviewed with a fresh set of eyes, a

site visit was conducted, DRD and COWI site staff were interviewed, the construction

schedule was assessed by considering three scenarios, and suggestions on how to improve

the schedule are provided.

This report covers:

›

A brief description of the bridge (Section 2);

Current state of design & construction and remaining work (Section 3);

SBJV's design & construction schedule (proposed, updated, and actual) (Section 4);

Site visit & observations (Section 5);

Analysis of schedule for three potential scenarios (Section 6);

Assessment of construction schedule going forward and recommended measure to

improve the construction schedule (Section 7); and

›

Summary & recommendations (Section 8).

In this study, three different construction scenarios are considered. Using the progress to

date to predict the future is not meaningful as only a few precast segments have been

produced and extrapolating their production duration would lead to an unrealistically long

construction period. However, there is no doubt that it is feasible to increase the

construction speed. It will take some time to ramp-up production and the production rate

might vary depending on steps taken related to workforce and equipment. Considering all

of these, the three scenarios considered in this study are:

›

Scenario 1: Pessimistic case – slow ramp-up and slow progress.

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STORSTRØM BRIDGE

INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

›

Scenario 2: Realistic case – ramp-up and progress between Scenarios 1 and 3.

Scenario 3: Optimistic case – ramp-up and progress expected for a well-organized and

experienced design & build team working collaboratively.

This study finds that if radical changes to construction are not implemented by January

2022, it will be unlikely that the new bridge can be opened to road traffic and that it will be

ready for installing the catenary system for railway by second half of year 2024.

The radical changes might include one or more of the following (each would take some time

to implement, hence, a decision needs to be made regarding which one(s) to adopt

quickly):

›

Adding a major international contractor with a large workforce (including workers,

foremen, engineers, and management staff experienced in similar major bridge

construction projects) and equipment to the SBJV team.

›

SBJV increasing its own capacity with a large injection of workforce (including workers,

foremen, engineers, and management staff experienced in similar major bridge

construction projects) and equipment well beyond currently on site.

›

Working on multiple fronts by switching to traditional in-situ construction for parts of

the bridge.

›

Adding one more precast girder production facility.

A significant investment by SBJV has been made in the prefabrication yard and the

equipment. The segment fabrication facilities and segment installation equipment are

appropriate for the project; however, they need to be utilized much more effectively than

they have been to date. Even if the facilities and equipment are used effectively, it will still

be very challenging to complete construction by mid 2024.

Completion of design, including design approvals, is not expected to be critical. It is

recommended that SBJV be open to DRD's design improvement suggestions for increasing

construction speed.

Additional measures are recommended to improve SBJV's operations and construction

schedule related to the following areas (see Section 7 for more details):

›

General Approach & Culture

Planning & Scheduling

Segment Fabrication

Storage

Offshore Operations

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STORSTRØM BRIDGE

INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

CONTENTS

2.1

2.2

3.1

3.2

3.3

4.1

SCOPE OF WORK

PROJECT DESCRIPTION

Storstrøm Project

Storstrøm Bridge

CURRENT STATE OF DESIGN & CONSTRUCTION AND

REMAINING WORK

Key Dates

Design Progress & Remaining Work

Construction Progress & Remaining Work

SBJV's DESIGN & CONSTRUCTION SCHEDULE

SBJV's Proposed & Updated versus Actual Schedule

SITE VISIT & OBSERVATIONS

ANALYSIS OF SCHEDULE FOR THREE SCENARIOS

SCHEDULE ASSESMENT & RECOMMENDED IMPROVEMENT

MEASURES

SUMMARY & RECOMMENDATIONS

Appendix A

Appendix B

Masnedø Yard Layout

High Level Schedules for Three Scenarios

A-1

B-1

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STORSTRØM BRIDGE

INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

›

SCOPE OF WORK

To evaluate the design and construction progress to date;

To assess whether the bridge can be open to road traffic and installation of railway catenary

system in the second half of 2024;

The overarching purposes of this study are:

›

To propose actions to be taken to improve progress of work in order to achieve the second

half of 2024 completion goal.

The scope of work of this study includes, but is not limited, to the following:

›

Analyse the remaining design and construction tasks to be performed.

Prepare a work plan for execution of these design and construction tasks, assuming a speed

of design and construction that can be expected from an experienced international bridge

design & build contractor.

›

Identify factors that might be obstacles to realisation of this work plan;

Assess their likelihood and extent of delay they could inflict;

Propose actions to minimise the likelihood of these obstacles occurring; and

Identify possible mitigating actions to limit their consequences if they occur.

Describe three scenarios and associated time schedules under these three different

assumptions for speed of construction and evaluate the likelihood of each.

›

Assess the probability that the bridge will open to road traffic in the second half of 2024.

Describe three different scenarios leading to different opening dates. For each of these

scenarios, assess their likelihood and describe assumptions and a justification.

Perform critical path analysis of the scenarios and identify the most critical activities in

the time schedules.

Propose actions to improve progress of work on site.

Taking past performance into consideration when predicting future progress, the following

activities are performed:

›

Analyse previous Work Schedules and past performance of SBJV on the project.

Analyse causes for previous delays and slip of the programme, including assessing the effect

of mitigation actions taken and/or not taken.

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STORSTRØM BRIDGE

INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

2.1

PROJECT DESCRIPTION

Storstrøm Project

The overall Storstrøm Project comprises (see Figure 1):

›

The new Storstrøm Bridge, an approximately 4 km long combined bridge with a double-track

railway, two-lane carriageway, cycle track and footpath;

›

Lowering of existing railway on Falster;

Embankments on Masnedø and Falster;

Roads and paths with related drainage;

Minor Underpasses and a roundabouts; and

Demolition of the existing Storstrøm Bridge.

Figure 1 - Storstrøm Project

This report focuses on the design and construction schedule for the new Storstrøm Bridge. The

schedule for the other components of the Storstrøm Project is not on the critical path and hence

are excluded from this study.

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STORSTRØM BRIDGE

INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

2.2

Storstrøm Bridge

The bridge is a concrete box girder bridge and has a total length of 3,832 m, see Figure 2. The

bridge comprises a central main cable stayed bridge (CSB), connected to land by two approach

viaducts. The cable stayed bridge has two 160 m long spans over the navigation channels. The

south viaduct has 23 spans of 80 m with a total length of 1,840 m. The north viaduct has one

span of 72 m and 20 spans of 80 m with a total length of 1,672 m.

Figure 2 – Bridge Plan & Elevation

For the areas close to Falster and Masnedø the foundations and piers 23S & 22S and 20N & 21N

are constructed in-situ by means of a temporary causeway. The remainder of the pier foundations

are precast concrete elements. There are three defined types of precast foundation ranging in

plan dimensions of 12m x 19m to 20m x 20m, see Figure 3.

Figure 3 – Typical Precast Foundation

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The first few bridge piers and pier heads are constructed using precast pier segments connected

to each other using 0.8m tall cast in place "stitches". The later piers are constructed using a

jump-form system for the lower pier, precast pier segments connected to each other using 0.8m

tall cast in place "stitches” for the upper pier, and then the pier head H1 is cast in-situ. See

Figure 4 for the later pier construction.

Figure 4 – Precast Pier Segments and Stitches

First two girder spans of the south viaduct (24S to 22S) and first two spans of the north viaduct

(22N to 20N) are constructed over land and/or temporary causeway using cast-in-place concrete

on falsework. The remainder of the spans are constructed using precast superstructure elements,

see Figure 5.

Figure 5 – Bridge Span Lengths

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The cable stayed bridge pylon foundation 1C is precast. After the foundation is placed in the

channel, the pylon is constructed using cast-in-place concrete methods, see Figure 6.

Figure 6 – Precast 1C Foundation and Cast-in-place Pylon

The cable stayed bridge superstructure spans (1C-1S and 1C-1N) comprise precast girders that

are erected on temporary piers, see Figure 7. Once the pylon is complete and the girders have

been positioned, the stay cables are installed and stressed.

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STORSTRØM BRIDGE

INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

Figure 7 – Main Cable Stayed Bridge Construction

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INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

CURRENT STATE OF DESIGN & CONSTRUCTION

AND REMAINING WORK

Key Dates

3.1

The key dates related to the Storstrøm Bridge design and construction are as follows:

›

Contract award – 26 February 2018

Supplementary geotechnical investigations were completed early 2019

Basic Design completed February 2019

Detailed Design is currently underway

Contractor mobilization on site – October 2018 (start of earth works for yard)

Prefabrication yard construction – October 2018 to March 2020

Start of precast segments:

›

Precast pier foundations February 2020

Precast pier segments July 2020

Precast girders November 2020

Start of cast-in-place foundations & piers:

›

South viaduct - F23S December 2019

North viaduct – F21N March 2021

Start of cast-in-place spans:

›

South viaduct November 2020

North viaduct Not yet commenced

Start of precast 1C foundation June 2020

The project had a slow start. For example, it took about 2 years from signing the contract to

casting first precast foundation bottom slab (for 21S), which should have started on 2019 March

(delayed by 12 months).

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STORSTRØM BRIDGE

INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

3.2

Design Progress & Remaining Work

Basic Design for the bridge was completed in 2019. Table 1 summarizes the Detailed Design

progress to date and the remaining design work.

Table 1 - Detailed Design Progress (as of 14th September 2021)

Number of Design

Packages in

Progress (not yet

submitted DRD)

Number of Design

Packages in Review

(submitted to DRD but not

approved / being revised

by SBJV)

Number of

Approved

Design

Packages

Total

Pier Foundations

Pier Shafts

Girders

Pylon & cables

Land works & other

packages

Ancillary Works

Major Temporary

Works

Total

135

1) Including 1C and under-foundations (number may vary as some packages containing both

foundations and piers have been split in a later revisions). Abutment foundations not included

2) Pylon foundation 1C is included in pier foundations above

a) Numbers from SBJV's DDDP v6, uploaded 10.09.2021

The design status as of 14

September 2021 is summarized on Figure 8, where:

›

Green solid and dotted lines: approved

Yellow: approval process ongoing

Unboxed elements: DP not submitted yet

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INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

Figure 8 – Design Status as of 14 September 2021

The key take-away from Figure 8 is that the design is well ahead of construction and SBJV has

the opportunity to work on construction of many segments and on many construction fronts.

3.3

Construction Progress & Remaining Work

The casting facilities and erection equipment seem to be appropriate for the job. However, there

does not seem to be sufficient storage space for all the pieces if the production rate is increased

to levels initially planned for the project.

The prefabrication yard on Masnedø Island has the following facilities (see Appendix A for layout):

›

A concrete batching plant: main and back-up facilities capable of producing 80 m³ per hour

and 40 m³ per hour, respectively. The maximum rate of production to-date has been ~30

m³ per hour. A learning curve is expected to be able to consistently achieve production

rates significantly more than that needed to-date to meet the full production needs of in-situ,

offshore, and precast construction.

›

Shed 2 & yard: Precast girder production line. It is planned to work on four girders at the

same time in a production line fashion.

›

Shed 3 & yard: Precast pier foundation production facility. There are two beds inside the

shed for casting the bottom slab and ribs. The foundations are then moved outside for

construction of the pier elevation. In the yard, there are four stations for pier construction.

›

Shed 4 & yard: Precast pier segment production facility. One casting bed for each segment

type (C1, C2, C3, C4, H1, H2).

›

Shed 5: Rebar processing facility (cut & bend).

Quay (140 m) for loading pier foundations and segments on to barges.

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INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

›

Storage area for various falsework, SPMTs, materials etc.

Table 2 summarizes the construction progress to date and the remaining work.

Table 2 – Construction Progress (as of 31st August 2021)

Number of

Units

Fabrication /

Construction

underway

Abutments

In-situ Spans

Precast Pier

Foundations

Precast Pier

Shafts

Precast Pier

Tops

Precast

Segment 0

Precast Girders

Precast 1C

Foundation

Pylon

CSB Precast

Girders

Cable System

Number of

Units

Fabrication

completed

Number of

Units Erected

Total

Percent

complete

100%

~35%

~15%

104

~15%

~2%

~1%

~90%

~15%

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4.1

SBJV's DESIGN & CONSTRUCTION SCHEDULE

SBJV's Proposed & Updated versus Actual Schedule

The production rates for different units are given in Table 3. The production rates given in SBJV's

proposal appear to be reasonable and consistent with what is expected from an experienced

international design and build team. The actual production is, however, much slower than

proposed by SBJV.

Table 3 – Construction / Fabrication Production Rates

SBJV Proposal

Work Schedule

F (months)

Work Schedule G

(C2) (months)

5.0

Actual (first/

average)

14.7 (P23S)

Cast-in-place

pier

Cast-in-place

girder

Precast Pier

foundations

Precast Pier

shafts

2 piers worth per

month

2 units per month

2.5 months

11.1

5.3

4.5

12 (est.) first

girder

2 (first cycle)

1.6 (first cycle)

9.4 (F21S)

Included with

precast pier

foundations

Included with

precast pier

foundations

Included with

precast pier

foundations

1.0

Incomplete

Precast Pier Tops

Included in Pier

shafts

Included with

precast pier

foundations

Incomplete

Precast Reduced

Deck Segments

Precast Girders

Included in

Precast Girders

2 months (2

spans per month)

0.7

Not commenced

3.0 (first cycle)

2.0 (first cycle)

5.4 (est.) first

girder

Precast 1C

Foundation

Pylon

CSB Precast

Girders

Cables

Already in place in

2021

25 months

19 months

8.4

5.0

19.2

22.3

Not commenced

3 months

3.1 (phase 1&2)

3.5 (phase 1&2)

Not commenced

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SITE VISIT & OBSERVATIONS

The site visit included an inspection of the main

Masnedø

Nedim Alca of COWI North America visited the site and interviewed the DRD and COWI site staff

between 13

& 16

September 2021.

yard, Sheds 2 through 5, and the abutments and in-situ spans at Falster and

Masnedø. A

summary of the site visit and interviews is provided below. This is not intended to be a

comprehensive list; it provides a flavour of the Project status, what has been working well, what

can be improved, and concerns going forward.

›

General

›

SBJV mainly engages subcontractors to perform the work on site. Initially the

subcontractor supervision by SBJV was inadequate, but this has improved through the

use of Site Supervisors. SBJV has also experienced difficulty retaining staff and

subcontractors and as a consequence of frequent staff changes, there has been

inconsistent production rates and quality. SBJV has recently started to employ ‘blue

collar’ staff to work directly under their control.

›

Subcontractors' lack of sufficient proficiency in English, which is the main language for

all site paperwork such as work methods and QA/QC documentation, is leading to

subcontractors not understating and/or not addressing project requirements. This is

resulting in inconsistencies in construction quality and speed.

›

SBJV increased technical, quality, supervision, and claim staff in Spring 2021, however,

still lacking experienced leaders.

›

Decision making process within SBJV seems to be slow. All decisions seem to be taken

above the project director level, making it difficult to resolve issues at the site.

›

After a slow start and change of the lead Designer, the design and the design review

process has become efficient. Currently, design is well-ahead of construction and

approved designs are available for a significant portion of the bridge. Completion of the

design is not expected to be critical.

›

The relationship between SBJV and DRD design teams appears to be well, however,

SBJV is not open to suggestions for design improvements which might improve

construction speed. Designers and Independent Checkers are talking to each other and

the weekly design meetings are productive and open.

›

Construction interface & planning are lacking, which is affecting production rate and

quality.

›

The number of construction workers appears to be very low for a project of this scale.

Most of the production is performed during one shift per day. Workers on site are

moved from one area or production line to another to address priority-of-the-day, which

is affecting productivity and quality.

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›

The main construction site at Masnedø Island has limited storage space to store

completed precast components. If and when the precast unit production rate is

increased, this might become an issue if there are delays with installation offshore.

›

Offshore work such as precast pier shaft stitch casting, Segment 0 production, precast

girder placement, main pylon casting, Power Joint casting, and all operations for the

main span construction have not commenced yet and will have learning curves. It might

be possible to use the area currently occupied by the Pier 1C foundation to store precast

pier foundations, precast pier segments, and/or precast girders. Barges can be rented

to store precast girders.

›

Quality Management, Inspection, Checking, and Re-work

›

SBJV's approach to quality management needs to be improved. Procedures and

documentation for the quality management system, work methods, team meetings etc.

are inadequate. Handling of NCR's and remedial & corrective actions do not seem to be

effective and do not seem to lead to corrective actions. Communication and

collaboration between SBJV's construction and QA/QC teams needs to be improved.

›

The SBJV does not operate their own Project specific document management system

(for example, Aconex) but relies upon ProjectWise (managed by the DRD), Microsoft

Teams and emails. This mixed use of systems by SBJV, and SBJV not providing

sufficient number of Document Controllers, have been challenging for smooth and

efficient flow of documents and information between parties to the Contract.

›

Construction quality in general is satisfactory for components constructed to date,

however, construction quality remains a concern due to high rate of workforce turnover.

›

Method statements and working procedures are prepared by inexperienced staff and

lacking details, except those prepared by specialist subcontractors, such as Fagioli,

which are appropriate. The persons nominated as Checker and Approver of these

documents need to review these documents more closely. The documents do not

appear to be used on site by the non-English speaking subcontractors due to the

language barrier.

›

Many Site Query Changes (SQC's) are not closed but this is not causing any work

stoppages.

DRD and COWI teams are working closely with SBJV's QA/QC team to avoid construction

delays despite unsatisfactory level of quality system documentation, however, the

concerns raised in the previous bullets can lead to work stoppages, rework, and delay.

When the production rate increases, special attention needs to be paid to integration of

QA/QC process and construction.

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›

Embankments

›

Construction of the embankments is on-going, however, there seems to be lack of

planning leading to rehandling of the material placed. This is not only a quality concern

but is also inefficient and costly for the SBJV. Regardless, the work on the

embankments is not expected to be on the critical path.

›

Abutments and in-situ spans

›

Both abutments are substantially complete. The construction of the

Masnedø

and

Falster in-situ spans is not expected to be on the critical path as the erection sequence,

temporary restraints, and closure procedures of the spans next to them can be modified

to suit if necessary.

›

Construction of the Falster in-situ spans is underway. There are some cracks and

honeycombs in concrete, however, overall quality of construction is good. The

construction of the two Falster spans started ~11 months ago (the initial plan was to

construct both

Masnedø

and Falster in-situ spans in 10 months). Falsework design and

approval in accordance with the Danish Handbook on Falsework (due to SBJV's lack of

planning and lack of sufficient workforce) are some of the challenges.

›

Once the Falster in-situ spans are completed, the falsework will be moved to the north

side to construct the

Masnedø in-situ spans.

›

Dredging and foundation preparation & placement

›

The dredging and foundation preparation for placement of precast pier foundations is

not expected to be on the critical path. The learning curve is complete and the

appropriate equipment and subcontractors are on site.

›

All dredging for the foundations has been completed. It takes one week per pier to

perform the final preparations to place a precast pier foundation.

›

The inclusion piles for Pier 1C are complete. The inclusion piles for the remaining piers

(1N, 1S, 12S) are expected to start in October 2021.

›

Pier 21S precast foundation had issues during placement because the survey boat had

calibration error. Surface of the ballast was undulating above tolerance. NW corner has

a gap of 2-3 cm tall in a 4mx4m area. The foundation will be lifted, the screeding layer

corrected and then replaced.

›

Precast Pier Foundations & Piers

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›

Shed 3 contains two stations for precast pier foundation bottom slab & rib fabrication. A

third station is currently being prepared in the yard just outside of Shed 3, which will

help improve the production rate.

›

Method statements for work in Sheds 3 & 4 are appropriate.

It seems feasible to achieve production rates indicated in SBJV's stand-alone schedule

for the precast pier foundations with the facilities on site, however, there must also be

an adequate workforce.

›

The catamaran has lifting (currently certified for 2,550 tonnes) and height limitations.

These limit the height of pier shaft that can be cast on top of the precast pier

foundations. Employing cranes with higher weight capacity and higher reach would

minimize number of stitch joints for the pier shafts.

›

SBJV is considering eliminating stitches and cast all upper piers in-situ. This might be a

reason why there is currently no production of pier segments.

›

Precast Girders

›

The precast girder production line in Shed 2 is sophisticated and well-suited to produce

quality segments.

›

Method statements for work in Shed 2 are appropriate.

It seems feasible to achieve production rates indicated in SBJV's stand-alone schedule

for the precast girders with the facilities on site, however, there must also be an

adequate workforce.

›

Segment 0 is key to be able to install fabricated precast girders, however, there are no

forms on site currently. In order to speed-up construction and reduce offshore work, it

would be beneficial to re-evaluate the Segment 0 construction process. If large crane(s)

with sufficient capacity and reach are brought on site, Segment 0 can be cast in its

entirety (except for the "wings").

›

Pier 1C and Cable Stayed Bridge

›

Pier 1C precast foundation is almost complete and planned to be installed in early

October 2021.

›

Currently, no drawings or method statements have been submitted for Power Joint and

Upper Pylon.

›

The current plan for offshore casting involves the use of static mixers on a barge. The

batched concrete is loaded into mixers for transportation to the quay, and then

transferred to the static mixers. The barge is then towed offshore to where the concrete

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is needed, such as the pier body stitches, the pier heads, the Lower and Upper Pylon

and the Power Joint. The double handling of concrete, instead of pumping directly from

the concrete trucks, could lead to concrete waste (due to rejecting batches) and cold

joints & honeycombing. Significant learning curve related to offshore in-situ casting is

expected.

›

The Lower Pylon is planned to be cast in 4m lifts, which is similar to other cable stayed

bridges.

›

Only preliminary design drawings are available for the temporary works related to the

cable stayed bridge main span girder installation.

›

Stay anchor boxes design package and stay cable lengths & stressing information have

been received.

›

The current design for the Power Joint requires many construction joints, which is not

desirable for areas with congested reinforcement. It is recommended that the Power

Joint be cast with as few construction joints as possible.

›

Other

›

Waterproofing system is currently being discussed. The current plan is to install water

proofing in the winter, which has been raising quality concerns.

›

The bearing design has changed, which is affecting bearings already on site. In total

eight bearings will be discarded, and 56 bearings will be returned to the manufacturer

for rehabilitation.

›

The last full programme to be formally submitted by SBJV to the DRD was Work

Schedule Revision F on 13

October 2020. The SBJV is now in excess of five months

behind this schedule and because of this, it cannot be used with any confidence to

determine the SBJV’s future activities.

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ANALYSIS OF SCHEDULE FOR THREE SCENARIOS

Three different design and construction scenarios are considered to assess whether the bridge

can be open to road traffic and be ready for installing catenary system for railway in the second

half of 2024. In this section, the scenarios and the analysis performed are discussed.

Using the progress to date to predict the future is not meaningful as only a few precast segments

for different parts of the bridge have been produced and extrapolating their production duration

would lead to an unrealistically long construction period. There is no doubt that it is feasible to

increase the construction speed, however, it will take some time to improve the production rate

(referred to as "ramp-up") and the actual production rate would depend on many factors, e.g.

level & skill of workforce, planning of activities, number of work fronts and more.

The three scenarios considered in this study are (see Figure 8 for a graphical representation):

›

Scenario 1: Pessimistic case – slow ramp-up and slow progress. This scenario has progress

faster than that observed to date but still very slow compared to that expected from a well-

organized and experienced design & build team.

›

Scenario 2: Realistic case – ramp-up and progress between Scenarios 1 and 3.

Scenario 3: Optimistic case – rapid ramp-up and progress expected from a well-organized

and experienced design & build team and all parties working collaboratively.

Scenario 3

Production Rate

Scenario 2

Scenario 1

Time

Figure 8 – Graphical representation of the three scenarios

The main assumptions and the assumed production (fabrication and installation) rates used for

the three scenarios are shown on Tables 4 and 5, respectively.

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Table 4 – Scenario Main Assumptions

Scenario 1

Ramp-up (full

production rate

achieved by)

Fabrication

Twice as long as

Scenario 3

Installation

Twice as long as

Scenario 3

July 2022

Scenario 2

April 2022

Scenario 3

January 2022

Between Scenario 1

and Scenario 3

Between Scenario 1

and Scenario 3

Fabrication durations

equal to SBJV proposal

Installation durations

equal to SBJV proposal

Table 5 – Assumed Production (Fabrication and installation) Rates for Scenarios

Scenario 1

Precast Pier

foundations

Precast Pier shafts

1 unit per month

(total = 34 months)

1 pier worth per

month (34 months)

Precast Pier Tops

Included in Pier

shafts

Precast Segment 0

Included in Precast

Girders

Precast Girders

1 span per month

(total = 40 months)

Precast 1C

Foundation

Pylon

Cable Stayed

Bridge Main Span

Precast Girders

Cables

12 months

Already in place in

2021

48 months

38 months

Scenario 2

1.5 units per month

(total = 26 months)

1.5 piers worth per

month (26 months)

Included in Pier shafts

Scenario 3

2 units per month

(total = 17 months)

2 piers worth per

month (17 months)

Included in Pier shafts

Included in Precast

Girders

1.5 spans per month

(total = 30 months)

Already in place in

2021

36 months

29 months

Included in Precast

Girders

2 spans per month

(total = 20 months)

Already in place in

2021

24 months

4 months

9 months

6 months

The high-level schedules for the three scenarios are shown on Figures 9 through 11 (also included

in Appendix B for printing larger format).

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2021

O N

2022

J J

2023

J J

2024

J J

2025

J J

2026

J J

2027

M A M

Activity

Precast Foundations

Design

Fabricate

Install

Offshore Work

Precast Pier Shaft Segments

Design

Fabricate

Install

Offshore Work

Precast Superstructure

Design

Fabricate

Install

Offshore Work

Precast 1C Foundation

Design

Fabricate

Install

Offshore Work

Cast-in-place 1C Pylon

Design

Offshore Work

Cable-stayed Superstructure Construction

Design

Fabricate

Install superstructure

Offshore Work related to superstructure installation

Install cable-stays

Finishing Works

Design

Asphalt Overlay

Track Slab Installation

Track Installation

A M

M A M

M A

A M

Figure 9 – Scenario 1 High-Level Schedule

Activity

Precast Foundations

Design

Fabricate

Install

Offshore Work

Precast Pier Shaft Segments

Design

Fabricate

Install

Offshore Work

Precast Superstructure

Design

Fabricate

Install

Offshore Work

Precast 1C Foundation

Design

Fabricate

Install

Offshore Work

Cast-in-place 1C Pylon

Design

Offshore Work

Cable-stayed Superstructure Construction

Design

Fabricate

Install superstructure

Offshore Work related to superstructure installation

Install cable-stays

Finishing Works

Design

Asphalt Overlay

Track Slab Installation

Track Installation

2021

O N

A M

2022

J J

A M

2023

J J

M A M

2024

J J

M A

2025

J J

A M

2026

J J

2027

M A M

Figure 10 - Scenario 2 High-Level Schedule

Activity

Precast Foundations

Design

Fabricate

Install

Offshore Work

Precast Pier Shaft Segments

Design

Fabricate

Install

Offshore Work

Precast Superstructure

Design

Fabricate

Install

Offshore Work

Precast 1C Foundation

Design

Fabricate

Install

Offshore Work

Cast-in-place 1C Pylon

Design

Offshore Work

Cable-stayed Superstructure Construction

Design

Fabricate

Install superstructure

Offshore Work related to superstructure installation

Install cable-stays

Finishing Works

Design

Asphalt Overlay

Track Slab Installation

Track Installation

2021

O N

A M

2022

J J

A M

2023

J J

M A M

2024

J J

M A

2025

J J

A M

2026

J J

2027

M A M

Figure 11 - Scenario 3 High-Level Schedule

Figures 9 to 11 suggest that precast girder production is the critical activity and interrupting the

viaduct precast girder production to fabricate the cable stayed bridge main girders will likely

adversely affect the overall schedule due to learning curve involved (blue shaded durations).

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The analysis and conclusions for the three scenarios are summarized on Table 6.

Table 6 – Analysis and Conclusions of Scenarios

Scenario 1

Estimated

completion date

Critical path

items / issues to

resolve

Same as Scenario 2

Mid 2027

Scenario 2

End of 2025

Scenario 3

Mid 2024

Production rate,

workforce level, work

on multiple fronts,

offshore works

learning curve

Same as Scenario 2

Obstacles

Same as Scenario 2

but less impact

Concrete production

rate, precast segment

storage space, quality,

and safety

Same as Scenario 2

but more impact

Likelihood of

occurrence

Possible, however, will

still require significant

improvements to

current production

rates

Realistic only if radical

changes are

implemented (see

Section 7 for further

discussion)

Increase workforce (by

a factor of 4 or 5),

work on multiple work

fronts, consider

producing CSB main

span girders on a

second production line,

increase concrete

supply capacity, bring

more & larger marine

cranes

Unlikely unless radical

changes mentioned for

Scenario 2 are

implemented very fast

Potential

mitigations (also

see Section 7)

Similar to Scenario 2

The main risks to schedule are segment production rate, Segment 0 and Power Joint construction,

offshore work, safety, and quality, all of which can add one additional year or more to the

durations estimated for the three scenarios.

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SCHEDULE ASSESMENT & RECOMMENDED

IMPROVEMENT MEASURES

The site visit and interviews with DRD and COWI staff, and analysis of schedule scenarios

discussed in Section 6 indicate that:

›

If radical changes to construction are not implemented by January 2022, it will be unlikely to

be able to open the new bridge to road traffic and have it ready for installing catenary

system for railway by second half of year 2024.

›

The radical changes might include one or more of the following (each would take some time

to implement, hence, a decision needs to be made quickly regarding which one(s) to adopt:

›

Adding to the SBJV team a major international contractor with a large workforce

(including workers, foremen, engineers, and management staff experienced in similar

major bridge construction projects) and equipment.

›

SBJV increasing its own capacity with a large injection of workforce (including workers,

foremen, engineers, and management staff experienced in similar major bridge

construction projects) and equipment well beyond that currently on site.

›

Working on multiple fronts by switching to traditional in-situ construction for parts of the

bridge. This will require significant additional marine equipment (barges, cranes, tugs,

crew boats, etc.), falsework and formwork, and infrastructure suitable to allow a large

workforce performing offshore work.

›

Adding one more precast girder production facility, first to fabricate the main span

precast girders and then, if needed, fabricate some of the typical precast girders. The

precast girder production appears to be the critical activity and interrupting the typical

precast girder production to fabricate the main span precast girders potentially adds 8

months, 6 months, and 4 months to the durations of Scenarios 1, 2, and 3, respectively

(see Figures 9 to 11). The facility does not need to be as elaborate as that in Shed 2

and does not need to be a production line. It could occupy a space slightly larger than

the girder itself.

›

Significant investment has been made in the prefabrication yard (Sheds 2 to 5, concrete

batch plant etc.) and the equipment (SPMTs, catamaran, barges, cranes etc.). The segment

fabrication facilities and segment installation equipment are appropriate for the project;

however, they need to be utilized much more effectively than they have been to date. Even

if the facilities and equipment are used effectively, it will still be challenging to complete

construction by mid 2024.

›

Completion of design is not expected to be critical.

The following are additional measures are recommended to improve SBJV's operations and

construction schedule:

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›

General Approach & Culture

›

Improve communication between the site office staff and the workforce. Take steps to

eliminate language barriers and to improve collaboration.

›

Improve safety and quality culture. Any accident and/or reduction in quality can lead to

significant delays.

›

Look for opportunities to work on multiple construction fronts including segment

fabrication and installation. Preparation of one additional precast pier foundation casting

bed is currently underway, which is useful. Similar actions are needed for all other

operations.

›

Planning & Scheduling

›

Employ additional experienced construction engineers on site to work on work methods,

planning, scheduling and QA/QC.

›

Prepare stand-alone schedules for every segment fabrication and every offshore

operation. Currently, stand-alone schedules are available only for precast pier

foundation and precast girder fabrication. These are not detailed enough and are based

on single work shift.

›

Based on the stand-alone schedules and the actual production rates, continuously revise

the construction means & methods and seek for efficiencies in every operation.

›

Revise the rebar details and rethink number and location of construction joints to

improve construction speed and to minimize prefabrication yard and marine operations.

These might require design changes, which will require approvals by DRD, and hence

will require action well ahead of construction.

›

Segment Fabrication

›

Increase workforce and number of shifts per day, possibly in all sheds and operations.

Pre-fabricate reinforcement cages on several fronts in parallel before placing in the

formwork and stitching cages together.

›

Look for opportunities to modify rebar detailing for rapid construction. This will require

design changes and hence need proper planning.

›

Precast the pier foundations and piers in only one or two pieces to minimize offshore

operations.

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›

Precast the cable stayed bridge main span girders on a separate production line. This

will avoid interrupting the typical girder production and allow construction of the main

span girders independent of the typical girders.

›

Precast the entire Segment 0 (instead of partial precasting). The current scheme for

construction of Segment 0 requires many construction joints and large quantities of

concrete casting offshore.

›

Revisit concrete production capacity and if needed increase concrete production capacity

either on site or by using local concrete suppliers, which might require use of standard

concrete instead of SCC.

›

Storage in the

Masnedø yard is very limited, especially for the precast girders. When the

segment production rate is increased or if offshore segment installation is delayed, storage will

become an issue. Investigate options and take measures to address potential storage area

shortage.

›

Offshore Operations

›

Increase the size and number of the cranes. This will allow installing larger precast pier

foundation & shaft segments, largest possible Segment 0 segments, and minimize the

number of offshore operations and minimize offshore concrete placement.

›

Transport concrete to offshore locations by driving concrete trucks on to barges. The

current proposal requires double handling of concrete instead of directly pumping of

concrete from concrete trucks, which could lead to concrete waste (due to rejecting

batches) and cold joints & honeycombing.

›

Fabricate additional temporary works to allow installing multiple precast girders at the

same time.

›

Revisit Power Joint detailing and construction joints. The current design requires

multiple horizontal construction joints across congested rebar. It is recommended that

the Power Joint be cast with as few construction joints as possible.

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SUMMARY & RECOMMENDATIONS

In this study, the overall construction programme is reviewed with a fresh set of eyes, a site visit

was conducted, DRD and COWI site staff were interviewed, the construction schedule was

assessed by considering three scenarios, and suggestions on how to improve the schedule are

provided.

The three scenarios considered in this study are:

›

Scenario 1: Pessimistic case – slow ramp-up and slow progress.

Scenario 2: Realistic case – ramp-up and progress between Scenarios 1 and 3.

Scenario 3: Optimistic case – ramp-up and progress expected for a well-organized and

experienced design-build team working collaboratively.

This study finds that if radical changes to construction are not implemented by January 2022, it

will be unlikely to be able to open the new bridge to road traffic and have it ready for installing

catenary system for railway by second half of year 2024.

The radical changes might include one or more of the following (each would take some time to

implement, hence, a decision needs to be made regarding which one(s) to adopt quickly):

›

Adding a major international contractor with a large workforce (including workers, foremen,

engineers, and management staff experienced in similar major bridge construction projects)

and equipment to the SBJV team.

›

SBJV increasing its own capacity with a large injection of workforce (including workers,

foremen, engineers, and management staff experienced in similar major bridge construction

projects) and equipment well beyond currently on site.

›

Working on multiple fronts by switching to traditional in-situ construction for parts of the

bridge.

›

Adding one more precast girder production facility.

Significant investment has been made in the prefabrication yard and the equipment. The

segment fabrication facilities and segment installation equipment are appropriate for the project;

however, they need to be utilized much more effectively than they have been to date. Even if the

facilities and equipment are used effectively, it will still be very challenging to complete

construction by mid 2024.

Completion of design, including design approvals, is not expected to be critical. It is

recommended that SBJV be open to DRD's design improvement suggestions for increasing

construction speed.

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Additional measures are recommended to improve SBJV's operations and construction schedule

related to the following areas (see Section 7 for more details):

›

General Approach & Culture

Planning & Scheduling

Segment Fabrication

Storage

Offshore Operations

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A-1

Appendix A

Masnedø Yard Layout

STORSTRØM BRIDGE

INVESTIGATION OF WORK PLAN AND TIME SCHEDULE FOR CONSTRUCTION

B-1

Appendix B High Level Schedules for Three Scenarios