Selection of Roof Casting Formwork Systems for the Bird Island Project: Case Study. The paper illustrates the complexities involved in the selection and deployment of a formwork system through a study of the concrete formwork selection on the Bird Island Flats Tunnel project. This $290 million project was a part of the Central Artery/Tunnel project in Boston, Massachusetts. Because the conventional shoring methods could not produce the output needed to meet the project schedule and budget, the contractor solicited proposals from formwork manufacturers and chose the system from CONESCO Industries.

1. Selection of Roof Casting Formwork
Systems for the Bird
Island Project: Case Study
Presentors:
Muhammad Umar nazir (cn-015)
Imran naeem (cn-012)

2. Selection of Roof Casting Formwork Systems for the
Bird
Island Project: Case Study
• Authors:
Tariq Abdelhamid, Ph.D
Mohamed El-Gafy, Ph.D, P.E
Panagiotis Mitropoulos, Ph.D
• JOURNAL:
PRACTICE PERIODICAL ON STRUCTURAL DESIGN AND
CONSTRUCTION © ASCE / NOVEMBER 2009

3. Contents
• Abstract
• Scope
• Summary
• Objective
• Methodology
• Literature Review
• Data Analysis
• Conclusions

4. ABSTRACT
• Formwork is a major contributor to profitability—or the lack of it—on most large
and complex concrete jobs.
• Formwork has major consequences for the project schedule, as well as all related
trades, such as ironworkers and cement finishers.
• Consequently, selecting a formwork system and planning its field operations must
consider the effects of the system on the overall project.
• This may result in significant difficulties in meeting the project requirements.
• The paper illustrates the complexities involved in the selection and deployment of a
formwork

5. SCOPE
• This paper reports on an in-depth study of the formwork system selection
problem on the Bird Island Flats Tunnel project.
• The project is a part of the Central Artery/Tunnel project in Boston,
Massachusetts.

6. SUMMARY
• The challenge on this $290 million project was the budget and schedule requirements for the
tunnel roofs.
• The width and thickness of the roofs were on average 18.29 m 60 ft and 2.44 m 8 ft,
respectively.
• The conventional shoring methods were not able to keep the project on time for critical
interim milestones as well as on budget.
• The alternative forming systems available did not provide a solution because of the time
and effort required for setup and takedown operations.
• The management team solicited proposals from formwork manufacturers, and chose the
system from CONESCO Industries.

7. OBJECTIVE
• This study has two objectives:
• First to identify the issues involved in the selection and
sequencing of a custom-made formwork system
• Second to formulate a detailed analysis method to
improve decision-making.

8. METHODOLOGY
• The paper consists of two parts.
• The first part describes the project and presents the issues involved in the selection
of the formwork system. It identifies the complexities of the decisions that faced
the construction team, and describes how the selection was made and how the final
decision came about.
• The second part presents analytical methods and techniques to support the
decision-making process. A detailed analysis and comparison of formwork systems
is performed that accounts for all the key formwork parameters. Such analysis is
necessary in order to select the best system for the project.

9. LITERATURE REVIEW
• Conventional System
The conventional system available consisted of a number of aluminum joists
that are supported by standard I beams. The concrete is poured against 2.3 cm
3/4 in. plywood that is placed on the aluminum joist. The concrete, plywood,
aluminum joists, and standard I beams are supported on steel shoring legs. The
system is very similar to scaffolds used for work done at high elevations. The
systems available were categorized by the capacity of the shoring legs. 10, 25,
and 100 kip/leg shoring systems were available. The cross section and layout of
such a system is shown in Fig.

10. CONVENTIONAL FORMWORK

11. LITERATURE REVIEW
• CONESCO Roof Casting Machines
• The winning proposal for a formwork system called the “Roof Casting Machines”
was submitted by the CONESCO Corporation. Each Roof Casting Machine
consisted of two major components, a self-propelled traveler and the form set. The
traveler is a three-dimensional rectangular frame equipped with a gasoline engine
which makes it able to transport the custom form set to its desired location.
Hydraulic cylinders on the traveler are used for initial horizontal and vertical
adjustments of the form sets. The form set is also equipped with hydraulic cylinders
for further adjustment. A detailed illustration of the traveler and form set is shown
in Fig.

12. CONESCO ROOF CASTING MACHINE

13. Machine Types with Height and Width Changes
MACHINE
TYPE
HEIGHT
(meters)
WIDTH
(meters)
TRAVELLER
MIN MAX MIN MAX
I A 7.43 9.54 11.43 15.70 I A
I B 5.53 7.56 11.43 15.70 I B or II B
II A 7.41 7.60 12.95 22.71 II A or II B
II B 5.18 9.34 12.80 22.56 II B
III 6.28 9.05 17.53 28.50 III

14. CONESCO ROOF CASTING MACHINE

15. ANALYSIS
• M/O started the system evaluation process by comparing the available
conventional shoring systems and the CONESCO casting machines.
• This comparison was based on operating cost, acquisition cost, technical
performance of the systems, and ability to adjust formwork to tunnel
dimensions.
• The records we have state $4,772,300 in net savings, and 36 weeks saved in
schedule time, when comparing the conventional system to the CONESCO
casting machines

16. ANALYSIS
CONVENTIONAL CONESCO DIFFERENCE
COST ($) 1,500,000 3,500,000 -2,000,000
PRODUCTION
(m2/MH)
.42 1.62 1.2
MAN HOURS (MH)
REQUIRED
164,900 28,473 136427
TIME (WEEKS) 86 50 36 (8 months)
MH COST (50$/MH) 8,245,000 1,423,650 6,821,350
TOTAL COST ($) 9,745,000 4,923,650 4,821,350

17. CONCLUSIONS
• The case study has focused on time and cost related to the use of three different
formwork systems.
• A time-cost trade–off analysis was also followed when investigating alternative
sequencing schemes for the one system that was selected using computer
simulation.
• Contractors in projects involving nonconventional formwork must carefully
consider the implications of formwork systems selection and sequencing of
concrete casting operations.
• The use of simulation in this study reveals its utility to a long-term and
comprehensive approach to planning and management.