SCHOOL OF ARCHITECTURE, BUILDING & DESIGN

BACHELOR OF QUANTITY SURVEYING (HONS)

CONSTRUCTION TECHNOLOGY III (BLD60304)

GROUP ASSIGNMENT

GROUP MEMBERS:

1. WONG JIA JING (0327221)

2. YEAP PHAY SHIAN (0322243)

3. YEE JYH LIN (0322408)

LECTURER: IR. CHAI VOON CHIET

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TUTORIAL SESSION: SEC 2

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TABLE OF CONTENT

No. Content Page No.

1 1.0 Introduction

1.1 Industrialized Building System (IBS) 1.2 Formwork System

1.2.1 Steel Formwork System 1.2.2 Tunnel Formwork System

3-4

2 2.0 Tunnel Formwork Construction Process 2.1 Casting Process of Tunnel Formwork System

5-7

3 3.0 Advantages and Disadvantages of Tunnel Formwork System

3.1 Advantages 3.2 Disadvantages

8-9

4 4.0 Case Study

4.1 Case Study I – The Paramount Buckhead in Atlanta

4.2 Case Study II – Rohan Abhilasha in Pune, India

10-13

5 5.0 Conclusion

14-15

6 6.0 References 16

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1.0 INTRODUCTION

1.1 INDUSTRIALIZED BUILDING SYSTEM (IBS)

Industrialized Building System is a technique of construction whereby the components

are manufactured and in a controlled environment, either at site or off site, placed and

assembled into construction works.

Generally, there are five types of IBS in Malaysia that are:

Pre-cast concrete frames

Formwork systems

Steel frame systems

Prefabricated timber frames

Block work systems

1.2 FORMWORK SYSTEM

Formwork serves as a mould for concrete structural components in which fresh concrete

is poured only to harden subsequently. IBS formwork system includes steel, aluminum,

timber formwork system and so on.

Tunnel formwork system is a type of steel formwork system.

1.2.1 Steel Formwork System

Steel formwork system is considered as one of the ‘low-level’ IBS as the site casting is

still required for the system. As such, the issue of structural quality control arises. Despite

this, tunnel formwork system is still better than the conventional construction process as

the finishes is of better quality, constructions process is faster, costs saving and less site

labours and materials are required. Steel formwork does not absorb moisture from

concrete and it does not shrink or warp.

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1.2.2 Tunnel Formwork System

This report will mainly be focused on Tunnel Formwork System.

Tunnel Formwork System is classified as a type of steel formwork system. Known as a

modern method of construction (MMC), it is used widely in the construction of cellular

structures that consists of high degree of repetition, for instance, private housings,

commercial developments, hotels and prisons. All of these buildings have monolithic

structures. The system creates an efficient load bearing structure for use in a wide variety

of applications. Tunnel formwork comes in half units and in the form of an inverted “L”

whereby it is bolted together at the top to form each tunnel. The articulated struts brace

the horizontal and vertical panels, thus allowing the adjustment of horizontal level of the

slab and also simplifying the process of dismantling the formwork.

This formwork system ensures the laying of base concrete and wall concrete

simultaneously. It makes sure that the surfaces subject to concrete are made of sheet

metal. The prefabricated tunnel formwork can be reused up to 600 times and it is able to

suit a variety of module sizes. A 24-hour construction cycle can be achieved and the

buildability of in-situ concrete is improved by using tunnel formwork system. Tunnel

formwork works by creating cells, which can be easily subdivided to create rooms. If

longer spans are required, tunnel forms can be extended using a mid-span section.

Diagram (a) – Tunnel Formwork System

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2.0 TUNNEL FORMWORK CONSTRUCTION PROCESS

The on-site implementation of 24-hour cycle is separated into the following operations:

i. Stripping off the previous day’s formwork.

ii. Correctly placing the formwork for the current day’s phase by a tower crane.

iii. Installation of mechanical, electrical and plumbing services.

iv. Installation of reinforcement in the walls and slabs.

v. Pouring of concrete in walls and slabs in one single operation.

vi. Heaters fired up if necessary

vii. Overnight curing starts.

viii. The engineer carries out a concrete test to ensure that the previous day’s pour has

achieved the required strength.

When a storey has been completed, the process is repeated on the next floor.

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2.1 Casting Process of Tunnel Formwork System:

1) Prefabricated wall reinforcement is placed at the correct position by crane prior to

casting the kickers.

2) As two and a half tunnel is craned in position, it is bolted together and tied.

3) The wall concrete is poured.

4) Slab reinforcements are fixed.

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5) Slab concrete is placed. The formwork system allows the tarpaulins to wrap the pour

and for the usage of butane heaters to maintain a suitable high temperature. This is so that

the concrete can reach its desired strength overnight.

6) The tunnel- formworks are removed the next day.

7) The process is repeated for the next two bays.

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3.0 ADVANTAGES & DISADVANTAGES OF TUNNEL FORMWORK SYSTEM

3.1 ADVANTAGES

Quality

The precise, even steel face of the formwork gives a smooth and high-quality finish.

Wallpaper can be applied directly or a skim coat may be used to enhance the plastered

finish.

Time

Construction process is simplified due to the nature of repetition and the use of

prefabricated forms so construction process is speedier.

Costs

Monolithic construction results in saving on foundations. Tunnel formwork system

usually reduces the cost of the frame by more than 15%. Also, less labour is required. It

serves as a quicker return on investment.

Design

Flexibility in design and layout of the building gives more freedom in the building

outlook.

Safety

Tunnel formwork system consists of integral working platforms and edge protection

systems. It also requires less tools and equipment so accidents can be reduced on site.

Efficient

Since it has a repetitive nature, familiarity with operations is encouraged, leading to

improve in productivity and efficiency.

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Sustainability

The in-situ casting on site and the locally available materials can minimize transportation

impacts. Scheduled delivery and almost non-wastage produce a neater site. Furthermore,

concrete’s thermal mass coupled with the right insulation and boiler design reduces

heating costs.

3.2 DISADVANTAGES

Costs

Tunnel formwork system has a high initial cost and equipment and machinery costs are

relatively higher due to the cranes needed for each block. Due to speedy construction,

high cash flow required.

Dimensional Limitations

This system has low degree of modular flexibility. Lowered slab is not allowed since it

prevents the removal of formwork and suspended ceiling is required. Basement storey

cannot be constructed using tunnel formwork as the removal of formwork is not possible.

Various geometrical forms and angle are hard for special formwork to be designed.

Coordination Issues

The high production of this system relates to the management functions. As such,

coordination problems cause delays in schedule.

Skilled Labour

Skilled labour force is needed compared to conventional systems.

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4.1 Case Study I - The Paramount Buckhead in Atlanta

Diagram (b) - The Paramount Buckhead, Atlanta

The Paramount Buckhead in Atlanta, by The Hanover Company, Houston is a 44-storey

residential structure. It is one of the tallest residential structure ever constructed using

tunnel form and it is the third tunnel form project for the building’s owner. From this case

study, there are a few aspects that are identified:

Efficient in concrete casting

One floor can be completed in every 3 days. Completion of shell was completed

one month ahead as per schedule.

At the Buckhead site, it took only 5 minutes for a small crew to remove both half-

tunnel forms from the previous day’s placement and set them up at their next

location

85% of the work uses tunnel form which allow them to fulfill the contract with “2

homes per day” requirement.

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Affordable single-family residence & apartment

Tunnel form help reduce time to build structure because workers formed both

walls and decks in one operation hence reducing overhead cost

Refinements purpose

Ideal for project like these that offer repetitive framing opportunities. The more

repetitive steps there are, the greater the benefit.

Less chance of making mistake since its cycled-work based.

For the Paramount project, Stull reports that workers could easily locate the

tunnel forms precisely each time they were moved, so the building was only 3⁄8

inch out of plumb in its 44 stories.

Because of the smooth still skin of form, process pitching and painting on walls

and ceiling accelerates.

Speed of construction with a small crew is the most marketed benefit

Only a few workers are required to place ask the formwork needed for an entire

floor. Workers help to give instruction to the crane operator during installation.

Tunnel-formed building require low maintenance, and it’s strong & rigid structure.

Quietness

Strong selling point of this project.

There is no creaking or movement in the floors, and concrete walls transmit little

sound

Require good detail planning

To take full advantages of the system

Design around the use of tunnel form

Plan about daily flow of construction of this project where by labour force are

performing the same tasks each day

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4.2 Case Study II - Rohan Abhilasha in Pune, India

Diagram (c) - Rohan Abhilasha in Pune, India

Rohan Abhilasha is a residential project that used advanced tunnel form system in

Pune, India. It contains 25 towers, each having 12 residential levels with 2 ground

levels. Rohan Abhilasha is the first projects to employ the tunnel form system for

constructing the towers and the individual apartments in each tower in the area.

Tunnel form system was identified as the most suitable formwork system for the

construction of this multi-storeyed building with its speciality.

Shorter erection period permits an earlier recovery of capital

Tunnel form allow the contractor to lay wall and slab concrete at the same

time.

One layer is constructed with a set of formwork every day.

Has a production cycle of 1-3 days per floor.

Cost of financing the construction capital is considerably decreased with high

construction speed.

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Effectiveness in production and minimization of labour costs

Reuses the formwork from housing units a few times, result in effectiveness

in production of building.

Less labour required.

Assurance of Good Quality

Precast products that manufactured and cured in plant such as staircases

were used.

Made in monitored and controlled environment, therefore high product

quality and reliability.

Result in increased productivity after erection at a very short period of time.

Strong and durable against earthquakes

Located in country that suffers high frequency of earthquakes.

Tunnel formwork system that creates efficient load-bearing structures which

are known as the most earthquake resistant structures were used.

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5.0 Conclusion

Different formwork systems provide a wide range of concrete construction solution that

can be chosen to suit the needs of a particular development. As compared to the

conventional formwork, tunnel formwork which is a type of modern formwork systems,

which are mostly modular, are designed for speed and efficiency. When compared in

detail, tunnel formwork system promotes one day’s cycle per floor whereas conventional

formwork system on the other hand provide a minimum cycle time of 21 days. For

quality wise, the final concrete finish quality, plastering is not required for concrete that

adopt tunnel formwork but it is necessary for conventional formwork product. Even

though tunnel formwork requires high initial cost when compared to conventional

formwork system, it is still considered as economic especially for mass housing project.

In additional to cost factor, number of time of reuse for tunnel formwork system is also

much higher as compare to the conventional one. Reuse time of tunnel formwork system

would be around 300 to 500 times whereas for conventional formwork has maximum of

only 50 times.

Through the case study that we’ve chosen to analyse, it shows evidence of the beneficial

side of tunnel formwork. Quality of concrete finish is ensured, increase efficiency of

work and improve cost effectiveness of a project.

The main reason why India apply the use of tunnel formwork is because they are the

manufacturer. Tunnel formwork system was first discovered in France. It is then

duplicated by India and manufactured in India. Therefore, India adopt the use of tunnel

formwork in most of their construction. As for Atlanta, tunnel formwork system is

applied mainly because of structurer advantage. In America, the New Madrid earthquake

zone that could have a devastating earthquake that would be felt in nearly a dozen states,

researcher say, threatening large cities such as Atlanta. In content with this, tunnel

formwork is therefore applied not only for its structurer benefit but also for time

efficiency and cost effectiveness.

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Despite the beneficial side of adopting tunnel formwork in the construction industry,

safety precaution should be taken while applying the used of tunnel formwork. Heavy

machinery and on-site management are critical factors in implementing tunnel formwork.

Therefore, safety precaution would include training session given to labours to help

improve their knowledge and skills. Employer’s responsibility towards the health and

safety of all labour in the on-site environment also plays a significant role to ensure their

action do not harm anyone while working, including themselves. Besides, maintaining a

safe working environment is also very important. Without acknowledgement of

appropriate safety precaution, coordination problem may arise and would most probably

cause remarkable delay in schedule.

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6.0 References

https://theconstructor.org/concrete/tunnel- form-construction-technique/8574/

http://www.concretecentre.com/Building-Elements/Walls/Tunnel-form.aspx

http://civil-resources.blogspot.my/2010/06/formwork.html

http://tunnelformconstruction.com/tunnel%20form.htm

http://www.portisan.com/tunnel-formwork.html

http://web.itu.edu.tr/~kanoglu/crs_bps_cn_tunnelformworksystem.pdf

http://www.outinord.fr/siteanglais/indexanglais.html

http://edition.cnn.com/2015/08/17/us/americans-earthquake-risk-usgs/

http://www.rohanbuilders.com/blog/tunnel- form-construction-technique-at-rohan-

abhilasha-pune

https://propstory.com/home/pune/rohan-abhilasha-wagholi-pune/

http://www.concreteconstruction.net/projects/commercial- industrial/building-

with-tunnel-forms_o

https://www.irjet.net/archives/V4/i3/IRJET-V4I397.pdf

http://www.krishisanskriti.org/vol_image/07Sep201512090750.pdf

http://www.constructionworld.in/News/In-Form/87245