RTA Nad Al Sheba Paper Full

7/29/2019 RTA Nad Al Sheba Paper Full

1/10

GeneralDubai, one of the seven emirates

was just a small fishermen colony,

about fifty years ago (Fig.1a). But in

the past 35 years, i.e. after theformation of United Arab Emirates

(UAE), Dubai has developed by

leaps and bounds. Dubai has

become a hub for foreign Investors.

Dubai is known for its modern

structures, rapidly growing

civilization, foreign-tourism and

trade. It is one of the seven

emirates of the UAE where

maximum investment and

developments have taken place.

Ambitious projects like Burj-Arab

tower (Burj-Khallifa), Burj-Dubai,

Palm-Island, World-Island and

several other upcoming projects

(See Fig.1b) challenged the entire

engineering community. The local

government authorities are coming

up with projects that continuously

challenge the engineer and

modernize the habitat in Dubai.

But since 2007, Dubai is

experiencing very challenging

situation because of the global

slow-down.

Prestressed Concrete Bridges for Nad-al-

Sheba Race Course Development Project,Dubai- Lessons Learnt

AFCONS infrastructure Limited (which is the Infrastructure wing of

M/s Shapoorji & Pallonji Group) recently executed its first bridge

project in Dubai. It consisted of three prestressed concrete bridges

at Nad-al-Sheba (horse and camel) Race Course, for Roads and

Transport Authority (RTA) Dubai. During the execution, the team

members faced various problems and creative solutions were devised.

However, the project was completed in record time, fetching

appreciation from the client. Various techniques adopted and other

technical details of the project are presented in this paper.

Vivek G. Abhyankar,Sr. Manger (Design),

AFCONS Infrastructure limited, Mumbai

Figure 1a: A scene of old Dubai

160 NBM&CW MARCH 2012

Concrete Bridges


2/10

NBM&CW MARCH 2012 161

Concrete Bridges

Afcons, being one of the

pioneering construction companiesof marine structures in India and

getting diversified in other sectors

of construction like Infrastructure,

Nuclear and Industrial etc., was

keen to participate in the

international bid floated by RTA, for

the development of Nad-Al-Sheba

race course. As the tender was on

International level, construction

companies all over the world had

participated in it. But finally RTA

shortlisted Afcons, as the technical

and financial bids were most

competitive. Though it was not anew experience for the company to

work on foreign soils, the

responsibility to fulfill the

expectations of RTA was a

challenge before the project team.

(Afcons already had a considerable

experience in International projects

at locations such as Mauritius,

Madagascar (Africa), Ruwais (Abhu-

Dabhi), Iraq etc., but mostly in the

marine sector.) As RTA was

considered as a strict client to work

with, Afcons was alert during eachphase of construction.

RTA, formerly known as Dubai

Municipal Corporation had stringent

norms of construction. The entire

project was monitored by experts

from various parts of the world

under the shed of M/s Africon and

Al-Burj. Invariably the projects with

RTA are not given the Time and

Cost extension. The contractor

delaying on the projects may even

get black-listed, and will not beallowed to perform any project in

future in UAE. Officers from Britain,

Switzerland, Sudan, Pakistan, Iraq,

Sri Lanka were appointed by the

company to execute the work. The

client also had a team of competent

engineers with focused scope.

The overall project of Nad-al-

Sheba race course development

had four parts (packages) namely

construction of roads and bridges,

construction of water canal from sea

till the race course (for navigation

of visitors from other emirates), andconstruction of Main structures /

stadium, and development of

adjoining areas. Amongst these the

first package of construction of

roads and bridges was executed

by Afcons. The overall work gave

lots of learning to the organization

and entire site team. The author of

this paper is one of these teammembers. Hence the lively

experience shared by him &

presented in the paper would be of

interest to all.

Briefs About the

ProjectNad-al-sheba race course (See

Fig.1c) is located to the south of

world famous Al-Burj-tower. Sea

shore is also very close from the

race course. The areas like Camel

market, falcon house are very closefrom the project site.

The scope of work for Afcons

included construction of three

approach Bridges (namely MDN-1A,

MND-3D and the Main Bridge) to

the race course and construction of

main roads within the enter area

(See Fig.19, showing entire

alignment, scope of work),

construction of canal, partly below

the main bridge.

The fourth bridge, approaching

to the Race course building, called

VIP bridge (No. 2c in Fig. 19) was

a separate package in this tender.

The tendering of VIP Bridge was

done after processing first package.

The VIP was constructed by M/s

Figure 1b: A few modern structures (existing / coming up) in Dubai

Figure 1c: Nad-Al-Sheba Race course - birds eye view


3/10


Concrete Bridges

Balfour Beatty (See Fig.2). Another

package was to construct the

approach water canal. The

construction of canal was done by

M/s Dutco. The construction ofStadium building was executed by

M/s Mydan. For the roads and

bridges in the scope of Afcons, the

structural design was provided by

M/s Al-Burg and the Project

management consultant. For the VIP

bridge the design was provided by

a team consisting of M/s DNEC,

together with Africon UAE, Dutco

Balfour Beatty LLC, and Petrofab

Intl. FZC.

In the present paper, the works

executed by Afcons only are

described in detail. The key detailsof all the three Bridges are

described below.

Link-1A, Link-1B were completely

reduced from the current works

because of financial crises. Later

the South wing also reduced

partially.

Concrete grade used:

Super structure M40

Substructure M40

Reinforcement Grade used: Fe500

Project Duration: 19 months

Project cost: 498 M Dirham (after

Revision of scope)

PilingThe piles were driven using

Casagrande pile driving rigs. The

freshly driven bores were stabilized

using polymer solution instead of

conventional bentonite slurry. This

helped in maintaining a clean site.

A steel liner was used to stabilize

the top 10m of the freshly driven

bore. The designed capacity of each

pile below pier cap was 450 MT

and 600 MT below the Abutments.

As welding of rebars was not

allowed, couplers were used for

reinforcements in the piles, after

approval from PMC, Client and

testing lab. (Figs 3-15 show the

project at various stages of

construction). Table 1 shows

quantities involved and the time

cycle for construction of 18 m long

piles in this project.

Figure 2: The VIP bridge (recently completed by Ms/ Dutco Balfour Beatty LLC)

(a) Night View on VIP Bridge(b) Fish bone shape Steel frames

used in the VIP bridge

Project Technical Details


4/10


Concrete Bridges

Figure 3a: (Left) Rebar cage for piles getting ready, (right) final rebar cage for typical pile

Figure 3b: (Left) Pile Driving in progress, (Right) Pile-cap formwork by M/s RMD Kwikform

(i) Pile cutting device, to obtain desiredpile-cutoff level

(ii) Freshly cut pile before finishing (iii) Cut pile just after finishing

Figure 3c: Pile cutting


5/10


Concrete Bridges

Figure 3d: Reinforcements of the Piers are fitted by dedicated Rebar team and View of Pier immediately after de-shuttering

Figure 3e: Typical View of Pier Formwork supplied by M/s Anvem


6/10


Concrete Bridges

Figure 4, 5: RMDK formwork / staging for the bridge deck and Densely reinforced Prestressed concrete section

Figure 6. 7: Workers engaged in placing the Reinforcements and cable ducts at place and Typical View of Inner Bridge Formwork(M/s RMD Kwikform type)

Figure 8, 9: Bridge Expansion J oints and Bearings


7/10


Concrete Bridges

Figure 10, 11: Concreting of the bridge structure and Bitumen Road in progress

Figure 12: MDN-1A- view of portion of completed bridge(note the white epoxy coating)

Figure 13: Large width deck slab (


8/10


Concrete Bridges

Construction HurdlesWhen Afcons received a work order

for this project in August 2009, it

was a very pleasant moment.

Immediately the organization started

initial mobilization of resources

(man, material and machinery),

considering the importance of this

work. Here it is worth mentioning

that all the major works associated

with Infrastructure growth in UAE

are directly monitored by the

Ministry. Soon after acquiring the

site, the site team noticed the

clouds of Recession in all the

trades in Dubai, including the

construction projects. The team

noticed that most of the Mega-projects were on the verge of

getting Hold tag. The big projects

like Lagoons were already closed.

This created an unstable feeling

within the project team members.

After two months of initial

mobilization, the Project team

started working at site (Oct-Nov

2008). In UAE the Project offices

usually open at 6:30am / 7:00am

and close down the work at around

4:00pm, due to extreme heat. This

was a time of rainy season in UAE.

The rains imposed constraints in

the road construction and

underground works. This time was

utilized by the technical team

members, to minutely study the

Construction drawings, prepare

action plans, study the methods

followed in close by projects by

other International construction

companies, etc. During this study,the team noticed various missing

information / errors at a few places.

The same was discussed with

PMC, and queries were raised in

the form of RFI. The clients were

soon got flooded with many RFIs.

Hence consultant had to appoint

dedicated engineer to sort all the

RFI. Considering the fast tack nature

of project, Afcons team raised query

/ request to client (RTA) to pay

attention to this matter. On this RTA

instructed the contractor and

consultant both to solve the matter

at the earliest without affecting the

time and cost estimate. Soon the

consultant informed the contractor

that there are certain changes

expected to take place in the

engineering details, under re-

engineering.

In Dubai it is mandatory for any

party executing the works to have

Approval with Dubai municipal

Corp. To avoid any further delays

in approval (leading to wastage of

time) the organization decided toappoint an approved agency for

construction of piling activity. Various

approved companies were

scrutinized and M/s Swiss Bore was

finalized to start the work. As per

original contract, the bored cast-in-

situ pile of 1000 mm diameter and

32 m depth were to be constructed.

Immediately after constructing thefirst pile, the same was asked to

be load tested (using the Kentledge

method) by the PMC (see Fig.16).

The 32m pile showed very high

capacity during the test hence PMC

and client asked to perform one

more of 24m deep pile (the 24m

depth was estimated by

interpolation, though it was not an

exact approach, it was fairly logical

for friction piles in uniform strata

as exists in places like Dubai).

Soon the 24m pile was driven

and tested. The 24m also passed

the required load and settlement

criteria. The site team was asked

to proceed ahead with the piling of

bridge MDN-1A with 24m depth.

Soon the PMC started pressurizing

the contractor to further reduce the

length of the pile to 18m. The site

team wanted to recheck the same

with the tender provisions and the

soil investigation data provided by

the client. Finally with the reduced

scope, the 18m pile was driven

and tested at second bridge MDN-3D. The same also passed the

requirements. The consultant asked

the site team to proceed ahead

with 18m length of pile for the

Figure 16: Pile Load test (left) kentledge, (right) Jacks and Load cells on Pile head


9/10


Concrete Bridges

remaining work at MDN-1A and all

piles of MDN-3D. This iteration

consumed lot of time.

A typical load-settlement curve

of pile loading test is shown in

Fig. 17.

When the piling work of bridge

MDN-1A was about to get over, and

piling work of MDN-3D was just

started, the PMC asked contactor to

test a 16m deep pile and test the

same at last bridge. The 16 m

deep pile was tested and found topass the load-settlement

requirements. The client and PMC

both were very happy on this cost

saving. The PMC wanted to now

check the 12m deep pile. Here, the

Structural Consultant of the

bridge had to intervene,

asking to check the

minimum pile length to

resist the lateral loads, yetPMC got the approval from

client to get the 12m pile

checked.

Dubais soil stratum is

a typical example of fine

sandy strata with week

empty soil-pockets formed

during soil-storms. The

same was experienced

while driving 12m deep pile,

where the bore suddenly

got collapsed inwards.

Because of this, the clients

instructed to stop further re-

engineering and proceed ahead

with the 16m deep piles.

Unfortunately, the tendered quantity

had got almost half. Though the

PMC and the consultants, agreed

with 16m depth of the pile, the

second step of re-engineering was

started to reduce the number of

piles itself. But as the final pile of

16m was just meeting the

requirement, the number could not

be reduced drastically. Details of

completion of piles are shown in

Table 2.

The third step of re-engineering

was in the reduction of bridge length

in MDN-3D. Such reduction wasrequired because during the

planning stage the minimum

ground clearance for the bearings

was not followed by the Planner /

Consultants. Thus the initial few

months time (four to five moths

after initial mobilization period of

two months) was critical. The

organization could appoint a Project

Manager from Dubai, who can

speak the local language (Arabic),

and could communicate with the

clients and PMC in a better way,

and to keep an eye on the project

time loss. Then the organization

decided to work on 24 x 7 basis.

Three shifts in full swing were

started.

All these delays, trials, iteration

in first five / six months gave lots of

learning, which was used to trouble

shoot all further hurdles / issues.

The challenge was to maintain

quality, without losing time, money

and yet to give safe construction.

Now the organization geared-up to

do the work on time. Many otherproblems faced by the team, as

listed below, were carefully

addressed with sound engineering

solutions, to meet the target.

1) Delayed payments

2) Alteration / reduction in scope of

Figure 17: Details of Cyclic Pile Load Test-2

(left) Canal cross section (right) Excavation of canal in progress

Figure 18: Canal passing below the main bridge


10/10


Concrete Bridges

Outcome of This ProjectThe initial period of a few months was difficult for the

contactor. Both the parties were new to each other.

But once they understood the working style and the

project requirements in Dubai / RTA (client), the team

members could jointly overcome all the hurdles. Finally

the finished quality of output (as seen in various

photographs) was obtained. The credit also goes to

the various vendors, suppliers and the subcontractors,

as each one did their job the best.

ConclusionVery limited numbers of contactors from India take a

challenge to participate and construct international

projects. However, such contacts give lots of

knowledge, understanding about the International

construction practices, legal and contractual

provisions. Also such projects help the organization toearn lot of respect in the International construction

industry, in addition to the financial gains. Its worth

mentioning here that after completion of this project,

Afcons earned a place in the list of a few preferred

contactors to do jobs in Dubai.

Acknowledgment & References.

The author is thankful to the Afcons Infrastructure

Limited and entire site team for making all the relevant

data available for this paper. More information of this

project may be found in the following papers:-

1. Abhyankar V.G., Nad-al-Sheba Race Course

Development Project: Construction of three Bridges,

Quarterly journal of Indian Society of StructuralEngineers (ISSE), Mumbai, Vol-13/2, April-May-

J une2011

2. Karnik, M. D., M.R Birhade, and P.S. Bansod,

Experiences in Construction of Bored cast-in-situ

piles in calcareous soil Strata at Nad Al Sheba

Race Course, Dubai to be published in Proceedings

of Indian Geotechnical Conference, December

15-17, 2011,RTA Dubai (Paper No. Q-199.)

List of various Vendors / Suppliers / Sub-contactors

involved in the project :

Pile-driving M/s Swiss Boring

Formwork

o Superstructure (M/s RMD Kwikform),o Piers (M/s Anvem Steel)

Reinforcement cutting bending, BBSM/s Ulmost,

and partly done in house

Prestressing system M/s Nasa Structures (sister

co. of M/s VSL)

Bearings, Expansion J oints M/s Alga bearings and

Exp. J ts

RE walls and Geo textiles M/s Freyssinet

Concrete and other construction Chemicals :

M/s BASF

work under re-engineering

3) Delay in acceptance to RFI by PMC, action taken on

RFI

4) Construction workers issues

5) Idling of construction resources (machine / men) in

absence of approval / drawings

6) Administrative issues (pressure from other agencies /

contactors on client)7) Relocation of utilities

8) High magnitude of pre-stressing

9) Incompatible values of Stressing mentioned in

drawings, especially at cable coupler locations

At the Nad-Al-Sheba race course, a water canal was

planned to carry the passengers from sea shore and

other locations to the Race course building. The main

contractor for the construction of Water Canal was M/s

Dutko. But the construction of part of the canal passing

below the main bridge was the responsibility of Afcons.

Documents

RTA Nad Al Sheba Paper Full