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ICI Update - April 2011 01
Contents• From the President’s Desk 1
• News from Centres
th• 16 ICI (KBC) Civil-Aid (Torsteel) Endowment Lecture 6
- Construction of Underpasses in Restricted Boundary Conditions - Er. Jose Kurian
• Selected Seminar Papers 17
- Self Compacting Concrete for the Tallest Building in India - Mr. S.A. Reddi
• 27
• Student Chapters 28
• Forthcoming Events 29
• New Members 32
• Election Notice 33
Strengthening International Relations
From the President’s Desk
April 2011 Vol. 2 Issue: 04
In recent times, ICI has been receiving growing recognition in the international sphere. Our in t e rna t i ona l c on f e r ence , ACECON 2010, was not only co-sponsored by two world-renowned bodies, namely, the American Concrete Institute (ACI) and the Asian Concrete Federation (ACF) but also witnessed participation of experts from nearly two-dozen countries. The Roving Seminars on Sustainability held in January 2011 at Bengarulu, Nagpur, Jaipur and Kolkata were jointly organized by ICI and SINTEF, Norway. The recently-concluded Round Table meetings held at Mumbai, Bengarulu, Chennai, Hyderabad and Delhi were the outcome of joint efforts of ICI and t h e F e d e r a l H i g h w a y Administration, USA. Besides being helpful in disseminating technical information to Indian participants on the latest trends,
these events have enhanced ICI's image in international sphere.
With a view to reinforce this trend, I was quick to respond to ACI's invitation and attended ACI Convention held in Tampa, Fl.
nd thfrom April 2 to 6 , 2011. I made use the opportunity to establish contacts with the ACI President, the Executive Vice-President and other functionaries of ACI. I also met many well-known experts. All of them showed keen interest in the activities of ICI, while some have promised to participate in future ICI events. I witnessed functioning of the two ACI Committee meetings and attended technical sessions on performance requirements and testing. I must admit that all this was a great learning experience! Incidentally, I must acknowledge with thanks the immense help rendered by our GC member Prof Gajanan M.Sabnis during my visit to USA.
ICI can learn a lot from the ACI. Worldwide, ACI is known for its valuable technical documents which contain a plethora of information on a variety of topics in structural concrete. Such
excel lent compilat ion was possible through the painstaking efforts of a large number of technical committees of ACI. I am happy to inform that ICI has also made a small beginning in this direction and a draft document of the first ICI Committee is under circulation. ICI needs to form a number of Technical Committees and commence the work of p r e p a r a t i o n o f t e c h n i c a l documents which could be very useful to practicing professionals in India.
During ACI Convention at Tampa, I attended at least five technical s e ss i ons on pe r f o rmance requirements and testing. The t r e n d o f p e r f o r m a n c e specifications now seems to be p i c k i n g u p i n t h e U S A . Considering the fact that the shift from prescriptive to performance specifications is closely related to sustainability, ICI needs to make some serious efforts in bringing awareness about the new trend amongst its members and Indian professionals.
Vijay Kulkarni
President
ICI Update - April 2011 02
News from Centres
Indian Concrete Institute, Ghaziabad Centre
and UltraTech Cement Limited jointly organized
Technical Symposium on March 26, 2011 at
Hotel Royal Residency, Saharanpur.
The function was attended by about 70
Researchers , Eng ineers , Arch i tec ts ,
Consultants from Saharanpur. Er.Rahul Goel,
Regional Head, Technical Services, UltraTech
Cement welcomed the members of ICI and other
delegates from construction industry.
Er.P.C. Sharma, Chairman, ICI Ghaziabad
Centre detailed on ICI and its upcoming event
i.e. National Conference on Repair and
Rehabilitation of Concrete Structures at Noida
during May 6-7, 2011.
ICI-Ghaziabad Centre
Lighting of Lamp by Dr. Rajeev Goel and Sh. Surit RoyDignitaries on the dias
Dinner Question-Answer Session
Er. A.K Sharma, Chief Engineer, CPWD was the
Chief Guest for the evening and delivered a
keynote address on “Durability of concrete
together with repair & rehabilitation methods”
and Er. P.C Sharma delivered his talk on
“Shankh-A novel ferrocement structure at
Ghaziabad”.
Dr. Rajeev Goel, Honorary Secretary, ICI
Western UP Ghaziabad Centre, coordinated the
function. Mr. Surit Roy, UltraTech thanked
every one for their participation and co-
operation for making the event successful. The
function was followed by cocktail dinner.
ICI-Pune Centre, organized a technical lecture
on Saturday 26.03.2011 titled 'Specialised
Concrete' by Er. Yusuf Inamdar at Arkey Engg &
Foundry Services, Pune 411 004. Er. Yusuf
Inamdaar touched upon various types of
special concretes.
ICI-Pune Centre
Er. Yusuf Inamdar delivering his lecture
Organized “ICI-North Bengal Centre” at Siliguri,
District Darjelling, West Bengal Organized a
technical lecture on “Repair and Rehabilitation of
concrete Structures”. Er. A K Sharma, Chief
New ICI Centre
th30 Centre at Siliguri
The function was presided over by Er. A K Sharma,
Chief Engineer, IBBMZ, CPWD, Siliguri, who also
gave the concluding remarks..
An Executive body of office bearers comprising of
Er. Shishir Bansal, Superintending Engineer,
Siliguri Central Circle, CPWD as Chairman, Er. G
K Bhaduri, consultant, Pioneer Engineering Pvt.
Ltd. as Hony. Secy. and Er. Pradeep Kumar,
Executive Engineer, Siliguri Central Division,
CPWD as Treasurer, was formed besides 6 other
members.
The programme was sponsored by M/S Pidilite
Industries Ltd. and was attended by 120 delegates.
Programme ended with cocktails and dinner.
Shishir Bansal
Chairman, ICI-NBC
Mr.Shishir Bansal, Chairman,ICI-NBC addressing the gathering
Er.A.K.Sharma, CE,CDO-CPWD making presentation
Section of the participantsChief Guest Mr.K.P.S.Ghuman, CE, MES addressing the gathering
ICI Update - April 2011 03
News from Centres
Engineer, CDO, CPWD, New Delhi presented the
key note lecture on “ Causes of Deterioration of
Concrete” followed by presentation on 'Building
repairs' by Er. Atul Vaidya, Head of technical
Marketing-Pidilite Industries Ltd. and Er. Sudhir
Samant Head of training and application - Pidilite
Industries Ltd.
Brig. K P S Ghuman, Chief Engineer MES, Siliguri
Zone was the Chief Guest,
ICI Update - April 2011 04
News from Centres
ICI-Ahmedabad Centre
Report on Lecture organized by ICI, Ahmedabad Centre in association with Ambuja Cement
ICI-Ahmedabad Centre organized a technical thlecture on 14 April, 2011 at Bhaikaka Hall,
Ahmedabad in association with Ambuja Cement,
GICEA and Institution of Engineers (Gujarat State
Centre) on “ Sustainable Cements and Concrete for
the Structures in the Climate Change Era”. The
lecture was delivered by Mr. P.K.Mehta (Professor
Emeritus in civil and Environmental Engineering,
University of California, Berkeley, USA). More than
two hundred and fifty professionals attended the
lecture.
Mr. Umesh Soni (Secretary- ICI, Ahmedabad Centre) introducing the Speaker
Mr. P. N. Jain (Chairman - ICI, Ahmedabad Centre) on the Dias with the Speaker
A section of the audience Mr. P.N. Jain,Chairman (Ahmedabad Centre) falicitating the Speaker
ICI Update - April 2011 05
News from Centres
Dr.Mehta discussed in depth about Sustainability
in Construction industry with relevant data and
also presented outcomes of some scientific
research. He also discussed some case studies
using HVFAC technology. The lecture was
followed by question and answer session.
Participants interacted enthusiastically with the
speaker.
Earlier Mr. Bharat Modi. President-GICEA
welcomed the gathering. Mr. Mukesh Majithia,
VP-GICEA, Mr.Pradeep N. Jain, Chairman, ICI-
Ahmedabad Centre and Mr. Hitesh Barot,
Customer Support, Ambuja Cements Ltd.,
felicitated the speaker. Mr. Bakul Desai,
Secretary GICEA proposed vote of thanks.
P.N.JAIN Chairman ICI, Ahmedabad Centre
UMESH SONISecretary-ICI, Ahmedabad Centre
Dignitaries participated in the event
Plans are on the anvil to conduct several
competitions for student members at All India
Level and to award winners at the time of Annual
Event of ICI. Such events will provide immense
opportunity to you to exhibit your talents at the
National level and to interact with the experts from
the civil engineering field.
You will be hearing more from us soon.
R. RADHAKRISHNANSecretary General
Dear Student Members,
In response to your interest evoked in ICI we are
keen to extend more benefits for the students
community. In the recently held Governing
Council Meeting, decision has been taken to waive
the entrance fee of Rs.1000/- for you when you
apply for regular membership of ICI within an year
after your graduation. By this, you will be
recovering the entire annual fee you pay as a
student member.
ICI Update - April 2011 06
Construction of Underpasses in Restricted Boundary Conditions
Jose Kurian
Chief Engineer, DTTDC, New Delhi.
Abstract
Introduction : Rapid growth in vehicular traffic necessitated the provision of grade separators like flyovers
and underpasses in New Delhi. This paper covers up case studies on four underpasses constructed with
different technologies to overcome the restrictions of various kinds in these sites.
SCOPE: First underpass constructed at Punjabi-Bagh crossing was placed 12 m below the ground as it was
the lowest component of four tier grade separator. Iron-ore layers were provided on the base slab as
counterweight to annul the high uplift pressure.
Second underpass at Madhuban-Chowk crossing had a restriction of already planned Metro-rail in transverse
direction. High uplift pressure on the base slab due to high water table was countered by permanent pre-
stressed soil anchors.
Third Underpass at Prembari-pul crossing had to be designed within the restricted passage available between
the running irrigation canal and Metro Rail corridor.
Fourth Underpass at Moolchand crossing was to be provided beneath the existing Flyover in transverse
direction. Innovative techniques were used to provide diaphragm walls beneath the flyover and in between
the piers of existing flyover.
Conclusion : Implementation of modern techniques and innovative designs is the solution to all complexities
arising in the design of infrastructures.
KEY WORDS: Uplift, Ironore, Soil Anchors, Voiders, Diaphragm wall, couplers
Introduction
New Delhi, the Capital city of India had been facing phenomenal growth of vehicular traffic without the
proportionate growth of infrastructure. It resulted in all sort of traffic congestions, increase in pollution
level, exponential rise in traveling time, increase in stress level, etc. etc. To limit these levels, it was decided
to construct grade separators on important corridors. The traffic flow system of Delhi is a Ring-Radial
pattern with two concentric Roads popularly known as Ring Road and Outer Ring Road. Radials to these
rings connect the traffic to the heart of Delhi. Ring Road and Outer Ring Road are the life lines for citizens of
Delhi. As one of the improvement measures, it was decided to start with the separation of grades at every
junction of these circular roads, so that crawling traffic can be made to run without any interruption on
these two corridors.
Kind of grade separators provided were flyovers, underpasses or in combination of clover leaves as per the
site requirement as well as feasibility. Though many of these locations were good enough to provide flyovers
or underpasses, but some of them were not friendly enough to design the structures without deploying extra
design skills. In general, kind of restrictions faced were limited site available, existence of structures
constructed in past, high water table causing high uplift pressures on foundation systems etc. etc.
This paper covers the underpasses constructed in this decade at four such locations where the boundary
conditions were not favorable and special design inputs, geometric as well as structural, were required to
make the structure feasible. Four such locations identified are Punjabi Bagh crossing on Ring Road,
Madhuban Chowk intersection on outer Ring Road, Prembari Pul crossing and Moolchand crossing, both
on Ring Road.
th16 ICI (KBC) Civil-Aid (Torsteel) Endowment Lecture
ICI Update - April 2011 07
Punjabi Bagh Grade Separator
Location
Punjabi Bagh crossing is one of the important intersections on the Ring Road at its junction with Rohtak
Road in western part of Delhi. Here, the traffic volumes were very high along both the roads and therefore it
was essential to provide free traffic movement in both the directions.
Design Challenges
Number of residential and commercial buildings all around the crossing did not permit a full clover leaf.
Thus an innovative four tier grade separator was designed and provided for the first time in country. The
scheme provided for three levels for vehicular traffic and separate level for pedestrian movement. The three
levels for traffic movement are a flyover along Ring Road, an Underpass along Rohtak Road and a ground
level Rotary for turning traffic. Since the Underpass was the lowest component of the four tier grade
separator, it was provided at a depth of about 12 m below the natural ground level. Thus, the base slab was
subjected to huge uplift pressure of underground water. Figure 1 shows a cross sectional area of grade
separator with all components like flyover, rotary, pedestrian plaza and Underpass.
General Features
The six lane flyover is 828 m long consisting of 516 m stilt portion and 312 m embankment portion. There
are dual carriageways of 11.0 m each with 1.2 m central verge and RCC crash Barrier on either side. The
longitudinal gradient is 1 in 30 with a vertical clearance of 5.7 m and 2.5 per cent camber for drainage. A
Rotary of size 75 m x 50 m (25 m straight portion and semi circle of 50 m diameter on either side) has been
provided at ground level for turning traffic. A pedestrian plaza covering entire intersection on Ring Road and
Rohtak Road with four arms for entry / exit is another feature of this Project.
The 626 m long underpass along Rohtak Road below the surface level Rotary and pedestrian plaza caters for
two way traffic with 11 m wide dual carriageway, each providing 3 lanes. There is a vertical clearance of 5.5
m The central portion measuring 100 m of Underpass is covered to accommodate pedestrian plaza and
Rotary. The area on either side of this closed portion is open to sky laid at longitudinal slope of 1 in 30 with
two summit curves at extreme ends and two valley curves where open portions meet the covered portion.
Figure 2 gives a full view of Underpass along with other components after it was opened to traffic.
Figure 1 : Cross sectional area of Punjabi Bagh Grade Separator
ICI Update - April 2011 08
Figure 2 : Underpass alongwith other components
Structural and Constructional Aspects
From structural design and construction considerations the underpass was divided in four zones as under.
Central Covered Portion (Zone-IV)
The central 100 m portion of underpass is a covered one and has two levels. The lower one is the main
underpass for vehicular traffic, while the upper one is pedestrian plaza. In the central covered portion, the
integrated structural system consisting of 800 mm thick, 18 m deep diaphragm walls alongside the
underpass with one central row of intermittent 800 mm thick and 28 m deep diaphragm wall. The
diaphragm walls, outer and central panels, have been horizontally connected at three levels, i.e. at base slab
of Underpass, floor and roof slab level of pedestrian plaza.
Trellis Portion (Zone-III)
In this portion 800 & 600 mm thick and upto 12 m deep diaphragm walls on the outer side and 600 mm dia.
pile-column at 2.5 m c/c in the central verge have been provided. The trellis have been provided as struts at
top, above clear headroom of 5.5 m connecting diaphragm walls and central piles to take care of lateral earth
pressure. 500 mm thick RCC base slab has been provided at bottom, below iron ore, connecting diaphragm
walls. Figure 3 shows the cross sectional area of underpass with trellis in Z III.
Open Portion with Diaphragm Wall (Zone-II)
In this portion 600 thick, 4.5 to 7.5 m deep diaphragm wall has been provided. A 150 mm thick RCC wall has
been provided alongside the diaphragm wall to share the lateral load while also acting as facia wall.
Open Portion with Retaining Wall (Zone-I)
For depth up to 3 m, open excavation with conventional retaining wall integral with the base slab was
adopted.
Figure 3 : Cross sectional area of underpass with trellis in Z III.
ICI Update - April 2011 09
The uplift force due to buoyancy was a major factor in deciding the foundation system. The water table was
observed to be varying from 6 to 7 m below the ground level. For purpose of design, the buoyancy force in the
underpass was calculated considering water table at 3 m below of the original ground level and further to
ensure accuracy of the design assumptions during service life of the structure weep hole were provided in
the diaphragm wall at this level. The foundation system consisted of RCC base slab spanning between outer
diaphragm walls and thickness varied from 500 mm in Zone-II to 800 mm in Zone-IV.
Figure 4: Iron ore layers being laid over the base slab as counter weight
To counteract the uplift forces on base slab due to buoyancy, two alternatives were considered, one was with
the tension piles and the other was the use of dead weight to counter the uplift. Use of iron ore was preferred
over tension piles system for reliability, economy and speed of construction. The depth of iron ore layer over
base slab varied from 600 mm in Zone-II to 1300 mm in Zone III and 800 mm in Zone-IV.
Besides this, during excavation and construction of base slab till the laying of iron ore, the water level was
lowered and maintained at specified lower level through continuous operation of vacuum pump operated
well point dewatering system. Figure 4 shows the iron ore layers being added over the base slab to counter
the uplift pressure.
Madhuban Chowk Underpass
Location
Madhuban Chowk is one of the important intersections on the Outer Ring Road at its junction with road
designated as Road No. 41. Here, Delhi Metro Rail Corporation (DMRC) had already planned an overhead
corridor in transverse direction. To plan a flyover over and above the metro line with all mandatory overhead
clearances was not only a costly solution, but visually unpleasing hindering the sky line. This had caused
the restriction in providing a grade separator for vehicular traffic travelling along the outer ring road. Thus,
decision was taken to provide an Underpass along the outer Ring Road.
Design Challenges
Incidentally, during the Planning stage, when soil investigation was carried out, the underground water
table was found at just 2 m below the ground level, while the construction of underpass had required going
as deep as 7 m. Thus the deepest structural portion of the underpass i.e. the bottom of the base slab was
subjected to pressure of 5m high water column which was required to by countered. One conventional
solution was to provide tension plies or to add weight to the base slab by adding some heavier material like
concrete itself or a metallic ore. But providing any additional layer of any material would have required
pushing the slab further down. This in consequence would have further increased the uplift pressure on
base slab. In the instant case, the uplift pressure was already too high to have a reasonable thickness of
overweight. Other alternative of providing tension piles is also not a healthy solution in water bound area. In
the present circumstances, the feasible solution was to anchor the slab by means of ground anchors.
ICI Update - April 2011 10
General Features
The 555 m long Underpass caters for two way traffic, with 9 m wide dual carriageway, each providing 3
lanes. The central portion of the Underpass is covered with 1200 mm thick pre-stressed voided slab with a
clearance of 5.3 m for the through traffic. The length of this covered corridor is 60 m and is horizontal in
longitudinal direction, but with a camber of 2.5 % for draining out the rain water.
Fig. 5. Typical Cross Section of Underpass through the covered portion
The slab at top caters for cross traffic at grade. The area on either side of this closed portion is open to sky
laid at longitudinal slope of 1 in 30 with two summit curves at extreme ends and two valley curves where
open portions meet the covered portion. One arm of the Underpass is in curve with 4 % super-elevation and
remaining is provided with a normal camber of 2.5 % to drain out the rain water. Fig. 5 shows a section of
Underpass in covered portion.
Structural and Constructional Aspects
The construction of the Underpass was taken up from top to bottom. The side retaining walls were designed
and constructed as Diaphragm wall having thickness 800mm at deep portions and 600 mm at shallow
portions. As a part of top to bottom construction, first of all 800 mm thick diaphragm wall panels of closed
portion were cast followed by the casting of slab at the required level on the virgin soil only. After casting of
all diaphragm wall panels on both sides of Underpass, the excavation was carried out to remove the earth.
Since the water table in the Underpass area was too high, dewatering wells were provided at close intervals
to keep the water table low and ease out the construction activities like excavation, waterproofing, laying of
base slab and installation of anchors including pre-stressing and grouting etc. After successful installation
of the anchors, remaining works like PFRC wearing course, cladding to diaphragm wall with decorative
finish, crash barriers, planters etc. were executed and traffic was allowed through the Underpass.
General layout of anchors
Total 990 nos. soil anchors were provided in the area, wherever the slab was subjected to uplift pressure.
For the convenience of execution, all the anchors in complete underpass area were made of 40 T capacity,
but depending upon the uplift pressure expected, the spacing between the anchors had been adjusted. In
the shallow area, the spacing had been kept as 3.5 m centre to centre in both directions and when the depth
is increased to 4 m, the spacing was reduced to 2.5 m centre to centre in both the directions.
ICI Update - April 2011 11
Figure 6 : Details of the Anchor (L-Section and Cross Sections)
Design capacity of soil anchor
Initially Performance Test, Proof Test and Creep Test were conducted for 40 T capacity on 3 anchors in
project area in accordance with the FIP recommendations for the design and construction of prestressed
concrete ground anchors. The parameters adopted were bonded length of anchor as 10m, un-bonded length
of anchor as 10m and the dia of bore-hole as 150mm. Figure 6 shows the vertical section and cross section of
the typical anchor.
Installation and Prestressing of anchors
RCC Base slab (800 mm thick in the deep portion and 600 mm thick in shallow portion) was cast prior to the
installation of the anchors. While the base slab was casted, a through hole of 300 mm dia. was created at the
anchor locations and after the concrete was set and gained sufficient strength, 150 mm Ø bore in the soil
beneath the base slab was drilled using rotary drilling machine. As one of the corrosion protection measures
adopted to protect the strands, the anchors were grouted internally as well as externally with cement grout.
After grouting, the anchor was prestressed after a minimum of 21 days. The pressure grouting, injection-
grouting was carried out to effectively seal any loose pockets and eliminate the possibility of water oozing. All
anchorages were epoxy painted and covered with grout after stressing. The recess was then concreted with
non-shrink grout. Figure 7 shows the hydraulic rig C-6 in operating and Figure 8 shows the anchors
installed in position.
ICI Update - April 2011 12
Figure 7 : C-6 Hydraulic Rig in operation Figure 8 : Anchors installed in position
Fig. 9. A view of Underpass in operation
The base slab was overlaid by 75 mm thick poly-fiber reinforced concrete wearing course as a protection
layer to soil anchors and smooth riding surface. Fig. 9 shows a view of Underpass after the same was opened
to traffic.
Prem Bari Underpass
Location
Prembari Pul crossing is one of the important intersections on the Ring Road at its junction with road
designated as Road No. 37 (Raja Nahar Singh Marg). To facilitate the smooth movement of traffic, it was
decided to provide a grade separator at this intersection. Various options considered were the cloverleaves
interchange option which was not feasible due to space restrictions. The flyover option though good but was
not possible due to presence of DMRC structure on the western side. Considering the above constraints,
Underpass along Ring Road was the only feasible option to minimize bottlenecks for Ring Road traffic.
Design Challenges
Delhi Metro Rail Corporation (DMRC) had already constructed elevated corridor on its western side, while
Yamuna Irrigation Canal was existing on its eastern side. Due to these limitations on both the sides, the
Underpass was to be designed within the limited length of 255 m. This had caused the restriction in
providing a grade separator along the ring road. For a normal underpass with a covered portion of 35 m,
length of the underpass required is around 425 m keeping 1 in 25 as maximum permitted gradient and 30 m
long summit/valley curves. Figure 10 shows a view having the constraints of Yamuna canal bridge and
DMRC structure restricting the length of Underpass.
ICI Update - April 2011 13
Figure 10 : Underpass plan showing Yamuna Canal and DMRC Structure on two ends
The Underpass is constructed by partially raising the intersection from the existing ground level up to 3.5 m
and partially lowering the Ring Road to a maximum of 2.5 m from the current levels.
General Features
The 255 m long Underpass caters for two way traffic with 9.2 m wide dual carriageway, each providing 3
lanes. The central portion of the Underpass having a length of 35 m is covered with 1200 mm thick
prestressed voided slab which caters for cross traffic at grade. The area on either side of this closed portion is
open to sky laid at longitudinal slope of 1 in 25 with two summit curves at extreme ends and two valley
curves where open portions meet the covered portion. Figure 11 shows a section of Underpass in covered
portion.
Fig. 11. Typical Cross Section of Underpass through the covered portion
Structural and Constructional Aspects
The construction of the Underpass was taken up from top to bottom. The side retaining walls were designed
and constructed as Diaphragm wall having thickness 800mm at deep portions and 600 mm at shallow
portions. As a part of top to bottom construction, first of all 800 mm thick diaphragm wall panels of closed
portion were cast followed by raising the wall as the level of the central portion of the underpass was
designed as raised from normal ground level. Thereafter the slab was cast and after maturity of slab
concrete, the excavation was carried out to remove the earth followed by cosmetic works like 125 mm thick
PFRC wearing course, cladding to diaphragm wall, crash barriers, planters etc. Figure 12 shows a view of
Underpass after the same was opened to traffic.
ICI Update - April 2011 14
Figure 12 : A view of Underpass in operation
Moolchand Underpass
Location
Underpass at Moolchand interchange is one of the important intersections on the Ring Road at its junction
with Lala Lajpat Rai road in southern part of Delhi. Here, Delhi PWD had already constructed an overhead
corridor in transverse direction. It was not feasible to plan a flyover over and above the existing flyover. This
had caused the restriction in providing a grade separator for vehicular traffic travelling along the outer ring
road. Thus, decision was taken to provide an Underpass along the outer Ring Road.
General Features
422 m long Underpass caters for two way traffic with 9.15 m wide dual carriageway, each providing 3 lanes.
The central portion of the Underpass is covered with 1000 mm thick pre-stressed voided slab in M45 grade
concrete with a clearance of 5.3 m for the through traffic. The length of this covered corridor is 72 m and is
horizontal in longitudinal direction, but with a camber of 2.5 % for draining out the rain water. The slab at
top caters for cross traffic at grade.
Figure 13 : Typical cross-section of Underpass showing flyover in transverse direction
The area on either side of this closed portion is open to sky laid at longitudinal slope of 1 in 30 with two
summit curves at extreme ends and two valley curves where open portions meet the covered portion. Figure
13 shows a section of Underpass in covered portion.
Design Challenges
To provide an Underpass under the existing flyover was a big challenge. The first challenge was to restrict
the Underpass within the obligatory span of the flyover and saving its Piers and foundations from any kind
of settlement while laying the foundation of Underpass. Next challenge was to provide diaphragm wall in the
area beneath the flyover due to restrictions in height making impossible for the normal rig to operate in this
area.
ICI Update - April 2011 15
Structural and Constructional Aspects
The construction of the Underpass was taken up from top to bottom. The side retaining walls were designed
and constructed as Diaphragm wall having thickness 800mm at deep portions and 600 mm at shallow
portions. As a part of top to bottom construction, first of all 800 mm thick diaphragm wall panels of closed
portion were cast. For the construction of diaphragm wall at central 24m stretch beneath the flyover, having
limited headroom available for works (which is approx. 5.2 m), special rig (RH6) and special tripod for
reinforcement cage lowering were deployed. After construction of guide wall, the RH6 was erected. Rotary
drill of 800 mm dia was attached to the rig. Mud reservoir was filled up and trenching was commenced with
drill. Drill was rotated in the controlled head of bentonite mud. After predetermined drilling time, the drilled
muck was taken out with Reverse Circulation method. Figure 14 shows a view of the machinery deployed
for providing diaphragm wall under the flyover area and the earth slurry being flushed out.
Figure 14 : Working system of RH-6 Figure 15 : Coupled Reinforcement bars
Fabricating a reinforcement cage of 20 m height and then inserting in the vertical slit of diaphragm wall was
another challenging task. So, the reinforcement cages were fabricated in parts of 4 m height each and each
of them were joined by means of mechanical couplers. Each part of the cage inserted and kept on hold at
specific height for making a connection with next cage by mechanical coupler. The special tripod hoisted the
cage and then lowered it in to the complete trench. By this process, the total height of the reinforcement cage
was completed and inserted. Figure 15 shows the reinforcement bars connected by means of mechanical
couplers. After lowering the re-inforcement cage, trimie pipe was lowered in pieces (connected while
lowering) for full depth of trench, with the help of special tripod. Concreting was done with tremie method.
Thereafter the slab was cast and only after maturity of slab concrete, the excavation was carried out to
remove the earth. Remaining construction activities like excavation, laying of 300 mm thick RCC base slab
and PFRC wearing course, cladding to diaphragm wall with decorative finish, crash barriers, planters etc.
were executed and traffic was allowed through the Underpass. Fig. 16 shows a view of the Underpass after
opening to traffic.
Figure 16 : A view of Underpass with flyover on top
ICI Update - April 2011 16
Monitoring of Adjacent Structures
The diaphragm wall and adjacent structures were monitored for settlement and lateral displacement of the
surrounding soils during and after the construction of the wall. The settlement of the existing foundations
was measured by taking levels using leveling instruments. The displacement of the surrounding soils was
monitored using inclinometers installed in between the diaphragm wall and adjacent structures.
Conclusion
Designing of any structure may not be convenient at every location. Constraints do exist, but a feasible
solution is always available. It requires a good planning after considering the various options to overcome
any constraint. The four Underpasses discussed in this paper had some kind of limitations. Base slab of
Punjabi Bagh Underpass being too deep, had to bear a good amount of uplift pressure which was overcome
by adding counter weight in the form of iron ore layer on the base slab. In Madhuban Chowk Underpass,
water table being too high created high uplift pressure on base slab, which was annulled by providing 20 m
deep soil anchors at a spacing of 2.5 to 3.5 m c/c. Prembari Underpass had limiting length due to
permanent structure on eastern as well as western side and permissible gradients were achieved by raising
the height of Underpass at its centre. Moolchand Underpass was to be constructed under an existing flyover
and between the piers of obligatory span, thus innovative methods were used to provide diaphragm wall and
simultaneously protecting the foundation of Flyover from any kind of damages.
Acknowledgements
The authors are thankful to Er. Pradeep Garg, Executive Engineer, Punjabi Bagh Grade Separator Project,
Er. B B Badhwa, Executive Engineer, Prembari Pul Underpass Project and Er. K C Pant, Executive
Engineer, Moolchand intersection interchange Project who have provided the necessary information,
relevant data and project photographs, without which it was not possible to compete the paper in the
present shape.
References
1. Narayan D., Agrawal K. N., Chugh B.K. and Rustagi S.K., “Multi level grade separator at Ring Road”,
Journal of the Indian Roads Congress Vol. 64-3, December 2003, pp.453-479.
2. Bansal S., Gupta V., “Use of prestressed soil anchors in the construction of an Underpass in high water
table zone”, Conference Document of National Seminar on Innovative Load Transfer devices and th thFoundations, organized by IIBE Delhi State Centre, 13 and 14 January, 2006, pp.19-35
To all ICI Centres
Please forward us the audited accounts statement for the financial year 2010-2011 before the end of June
2011 without fail as it is mandatory to finalise the audited accounts of the headquarters.
R. RADHAKRISHNANSecretary General
ICI Update - April 2011 17
Self Compacting Concrete for the Tallest Building in India*
S. A. ReddiFellow, Indian National Academy of Engineering
Abstract
The paper presents important aspects of the M80 grade self compacting used in the construction of the
columns of Palais Royale, a LEED-platinum-rated green residential building, about 320m tall, under
construction in downtown Mumbai, India.
Introduction
Conventional concrete casting relies on compaction to ensure adequate strength and durability. Insufficient
compaction leads to voids, which reduces compressive strength, strongly influences the natural physical
and chemical protection of embedded steel reinforcement afforded by concrete. Concrete is compacted
manually using vibrators, often operated by untrained labour with insufficient supervision, overall
durability is reduced. Inadequate compaction affects the material but also have health and safety and
environmental risks with operators subjected to 'white finger syndrome' and high levels of noise. Self Compacting Concrete (SCC) was developed in Japan as a quality assurance concept and over the last two
decades is preferred by many countries; it fills into forms and around congested reinforcement without
vibration; fluidity is realised by proper mix, increased fine aggregates, addition of mineral admixtures, new
generation of polymer superplasticizers and better quality assurance.
SCC was introduced in India in the Nineties. The reconstruction of the Reactor dome of the Kaiga Atomic
Power Project is noted for the introduction of high performance concrete Grade M-60. During the
construction of Units 3 & 4 at Kaiga, SCC was introduced for heavily reinforced components; about
5000cu.m. of SCC was successfully laid. This was followed by a number of projects across India. The
present paper presents salient aspects of the M80 grade SCC for the columns of Palais Royale, a platinum
rated green residential building, about 320m tall, under construction in downtown Mumbai. About
50000cu.m. of SCC has already been realised.
Benefits of SCC
! Increased productivity levels leading to shorter concrete construction time
! Lower concrete construction costs
! Improved working environment
! Improvement in environmental loadings
! Improved in situ concrete quality in difficult casting conditions
! Improved surface quality
Disadvantages of SCC
! Increased material costs, especially for admixtures and fine aggregates
! Increased formwork costs due to possibly higher formwork pressures
! Increased technical expertise required to develop and control mixes
! Increased variability in workability
! Stringent quality control requirements
! Reduced hardened properties modulus of elasticity
! Increased risk and uncertainty associated with the use of a new product
Selected Seminar Paper
* Paper presented ACECON 2010 an Asian Conference on 'Ecstacy in Concrete' organised by Indian
Concrete Institute at Chennai in December 2010
ICI Update - April 2011 18
Brief Description Of Palais Royale, Mumbai
A 320m tall luxury residential tower is under construction in downtown Mumbai. The structural
components are of high strength concrete. The reinforced concrete columns were earlier designed with M60
grade concrete. Based on the author's intervention, the developers agreed to increase the concrete strength
to M80. This resulted in substantial reduction in the column cross section and reinforcement. There was a
further reduction with the use of Fe 500 grade reinforcement bars. The building is founded on a reinforced
concrete raft.
Residential flats start at a height of about 80m. The space below is utilized for amenities car parks, sports
facilities, swimming pools, Building Management System (BMS) facilities etc. The floor-to-ceiling height is
typically 4.2m, doubled in the case of villas at the top.
Figure 1: Photographs of the Progress in the Construction of Palais Royale, and a Computer Generated Skeletal View
Wind tunnel tests were conducted in Canada. Special precautions against fire and firefighting measures
have been incorporated. A sophisticated Building Management System is planned to be in place. High
Strength Self Compacting Concrete, grade M80 is used for all the columns.
Palais Royale design involves a podium that houses functional spaces which require an unobstructed
spatial layout in order to give a more impressive view. For the upper structure used as residential units,
more economical shorter span design is used for columns. The layout of the podium structure uses
regularly spaced columns in longer span design. The prestressed concrete transfer girders are located
between 70m and 80m level. These are specifically designed as support for columns between the lower floors
(used for car parking and as amenity spaces) and the upper floors, the residential spaces. Joining these two
areas, the transfer girder has been designed with a width of 1.5m and a record depth of 9m. The girders are
prestressed in two directions. The tendon ducts in addition to heavily congested reinforcement necessitated
use of SCC M60 concrete for the transfer girders.
The architects and structural engineers are from Mumbai, with proof checking done by an American
consultant. There are separate consultants for the Services, Electrical, Acoustic, Lift, Environment, Fire,
Windows, Façade, Waterproofing, Waste Management, Renewable Energy, Vaastu, etc.
Materials
The workability requirements for SCC are typically defined in terms of three properties: passing ability,
filling ability, and segregation resistance. Filling ability describes the ability of concrete to flow under its own
mass and completely fill formwork. Passing ability describes the ability of concrete to flow through confined
conditions, such as the narrow openings between reinforcement bars. Segregation resistance describes the
ability of concrete to remain uniform in terms of composition during placement and until setting filling of
formwork with a liquid suspension requires workability performance described as follows:
ICI Update - April 2011 19
0 Filling ability: Complete filling of formwork and encapsulation of reinforcement and inserts.
Substantial horizontal and vertical flow of the concrete within the formwork maintains
homogeneity.
0 Passing ability: passing of obstacles such as narrow sections of the formwork, closely spaced
reinforcement etc. without blocking caused by interlocking of aggregate particles.
0 Resistance to segregation: Maintaining of homogeneity throughout mixing and during
transportation and casting.
SCC is highly sensitive to changes in material properties and proportions and, requires increased quality
control. The consequences of deviations in workability are more significant for SCC. A slight change in water
content may have minimal effect on conventionally placed concrete but lead to severe segregation and
rejected work in SCC. Only ordinary portland cement (OPC) is used, as mineral admixtures are added
separately in the batching plant. After extensive trials, OPC from Ultratech has been chosen. Processed fly
ash retains spherical shape and reduces water demand. The small particle size increases the spread of the
particle distribution, also improves workability. Processed fly ash from Dirk India, Nashik, is used.
Initially condensed silica fume was used; subsequently, reliable sources for metakaolin have been identified
and are used. Silica fume improves concrete rheology and enhances stability when used at low dosages, i.e.,
4-6% by replacement of cement, but can have detrimental effects on rheology at higher dosages. Silica fume
is expensive (Rs. 25 Rs. 30 / kg) and the quantity is restricted just to satisfy the properties. More favourable
constructability-related properties are derived with metakaolin. With average particle size 20- 30 times
larger than silica fume, the water demand with metakaolin is lower. The result is a high-strength concrete
having improved workability, finishability, and a reduced tendency for surface dehydration and plastic
cracking. Being lighter in color than silica fume, metakaolin will not darken the color of the paste or mortar.
Metakaolin is a highly reactive aluminosilicate, capable of producing mechanical and durability properties
similar to silica fume. Unlike fly ash, blast-furnace slag and silica fume, which are by-products of major
industrial processes, metakaolin is a specifically manufactured mineral admixture. Kaolin clay or China
clay is used as the raw material for its manufacture. It is a fine, white mineral, primarily of hydrated
aluminium disilicate. Extensive trials were conducted before switching over to metakaolin. Due to higher
particle size, metakaolin requires less amount of admixture than silica fume for the same slump flow. It has
a creamier texture, generates less bleed water and has better finishability than concrete with silica fume.
Chemical Admixtures
PCE based admixtures are imported. After trials, three alternative sources were identified. Fresh trial mixes
were conducted before changing the brand of PCE based admixtures. Viscosity modifiers (VMA) are added to
increase the resistance to segregation. They are high molecular weight soluble polymers, which in aqueous
medium have increased viscosity because of their interaction with water. The use of VMA is desirable but
not essential.
Aggregates
Natural aggregates and/or crushed aggregates may be used. In Palais Royale, 20mm maximum size
crushed aggregates are used for columns up to 70m; reduced to 10mm for columns above 70m. Gravel is not
used, due to erroneous perceptions. The optimum gradation of fine aggregate for high-strength concrete is
determined more by its effect on water demand than on particle packing. SCC contains high volumes of
cementitious sized material. As a result, fine sands, are less suited for SCC due to the sticky consistency
that may result. Coarse sands are desirable in SCC. The grading of fine aggregates is less critical in SCC
mixtures. Locally available sand could not match the quality requirements for SCC since the silt content is
very high. Facilities for washing in Mumbai are expensive. Hence, fine aggregate has been obtained from
Gujarat. Use of locally manufactured sand is now under consideration.
Trial mixes for M80 SCC
Large number of trial mixes was conducted with various combinations. Fresh and hardened properties
achieved in the laboratory are sometimes different from those achieved in full-scale production.
Therefore, trial batches were produced in the site batching plant. The E-value was tested, and found to
be similar to that of ordinary high strength concrete.
ICI Update - April 2011 20
Post-28-day designated acceptance ages
The selection of materials and mix proportions for high-strength SCC may be based on a designated age of
56 or 90 days rather than the traditional 28 days. For high rise buildings, loading conditions are such that
the design strengths are not needed until much later. At Palais Royale, a large number of extra cubes are
cast and tested for 56 and 90 days. Results are used for accepting concrete of occasionally lower 28 day
strength and for possible revision of structural design of columns based on 56 day strength, a common
practice in the USA. Based on statistical evaluation of works test results, the approved mix may qualify for
M90 / M100. Taking advantage of post-28-day strength gain, choosing a designated age of 56 or 90 days
allows for a reduction in the paste content of the mix, which can be highly beneficial in reducing total
shrinkage and improving long-term durability potential.
Handling of constituent materials
Materials are stored in the same manner as for production of vibrated concrete; in ground bins, silos, and
tanks for admixtures. Consistency of raw materials is controlled more frequently. Best practices are applied
on the maintenance of stockpiles of materials, i.e. moisture contents, free drainage, cleanness, and
prevention of segregation.
Production of SCC
Two 45 cu.m. batching plants are installed at site as the RMC supplies were not forthcoming for M80 SCC.
Trials were conducted to ensure complete mixing. A minimum of one minute mixing time was decided upon,
against the standard mixing time of 30 seconds. Considering the uncertainties involved in transportation,
feeding the concrete pump, laying the concrete pipelines and possible placement delays, it was decided to
allow for about one hour of delay between production of concrete and placement. The European Guidelines
provide for three levels of slump flow: SF1 (550-650 mm) appropriate for slightly reinforced structures; SF2
(650-750mm) suitable for normal applications and SF3 (760-850 mm) for very congested structures.SF2
should have been used for this project. However, a slump flow of about 800mm was adopted to cater to
uncertainties.
Constructability Properties
Constructability refers to the properties that are necessary for the mix to be produced, delivered, placed,
consolidated, finished, and cured, to achieve the required mechanical and durability properties. They
include slump flow, workability retention time, Pumpability, Finishability, and setting time. Work was
streamlined over a period of time after great deal of conflicts and dialogue between the production and
execution teams.
Transportation and Placement of SCC
Six cu.m. capacity truck mixers and concrete pumps capable of pumping concrete to the full height in one
stage are provided. Tests are conducted for each load of concrete discharged by the transit mixer: 1) Slump
flow test, 2) V-Funnel Flow Time, 3) L-Box (passing ability), 4) T-500. The concrete is distributed through
pipes supported on Self Climbing Placer Booms. The columns and shear walls are jump-formed. The form
panels use a unique patented system, scratch-proof and capable of unlimited use, realizing smooth surface
not requiring further treatment or plastering. The mix is designed for high early strength to enable removal
of formwork (with props left under) in 24 hours of concreting. A four day time cycle per floor is aimed at.
Modulus of Elasticity
The modulus of elasticity of conventional-strength concrete increases proportionally to the square root of
the compressive strength. While many empirical equations for predicting modulus of elasticity are
proposed, few equations predict the E-value of high strength SCC as accurately as they do for conventional-
strength concrete. A series of trials were conducted at site, confirmed by other laboratories, and the results
fed to the structural designer.
ICI Update - April 2011 21
SCC Robustness
SCC does not change from truck mixer to formwork; no one on the site can add water and absence of
vibration does not affect the homogeneity of the mix. This is an extra robustness that standard concrete can
never reach. Slump flow loss occurs between the batching plant and feeding into the concrete pump due to
variations in the input, batching errors etc. Any attempt to redose admixtures at the delivery end is resisted.
In extreme cases, the particular batch is rejected. There has been conflicting requirements as viewed by the
engineer in charge of placement and the engineer in charge of concrete production. While the field engineer
generally asks for higher slump flow values, the concrete production engineer sticks to the value specified.
Increasing the slump flow generally results in segregation of concrete, pipeline choke etc.
Homogeneity in the structure is higher than using normal concrete; specimens are really representative.
These conditions allow designers to choose higher loads for the material with benefits in dimensions, weight
and costs. Complicated geometries become now easy to fill, such as sharp corners, inserts as boxes or
windows in the walls, thin sections, areas with no access or with congested reinforcement. SCC is a state of
fresh concrete; hardened all characteristics are the same as normal concrete of similar strength.
3.11 Permeability
There is a reduction in permeability due to the high content of fines in the mix. Tests carried out with
comparison to standard concrete mixes having the same water/cement ratios gave impressive results.
Water penetration is reduced to about one third; penetration depth increases more slowly. This may be due
to the presence of fines particles to maintain a compact structure. So, SCC can guarantee a reduced
permeability. Spread between average and maximum penetration depth is reduced in SCC.
3.12 Grade of Concrete
The columns of Palais Royale were initially designed using M60 concrete. After considering the highly
congested reinforcement, it was decided to use M80 self compacting concrete. The designs were duly
revised, resulting in substantial reduction in column sizes and consequent increase in carpet area. In India,
adaptation of SCC for higher grades of concrete is still in its infancy; some building and bridge projects have
sporadically used high strength SCC. M80 Grade SCC has probably been used for the first time in India at
Palais Royale in Mumbai. The beams and slabs are in 60 MPa grade concrete.
Figure 2: Casting SCC - a one-man operation Figure 3: SCC flowability, passability and stability
Workability Retention
Workability retention and setting time are different properties, evaluated separately. Workability retention
depends on admixture type and dosage, mix proportions, concrete temperature, weather conditions etc.
Workability retention should be tailored to application because excessive workability retention is
unnecessary and may increase formwork pressure and segregation.
ICI Update - April 2011 22
Setting Time, Bleeding
The setting time of SCC is typically similar to that of conventionally placed concrete. However, due to the use
of chemical admixtures and mineral admixtures in SCC, setting time could increase or decrease based on
mix proportions. Polycarboxylate-based HRWRAs generally result in less of a delay in setting time. Given its
low water content and high viscosity, SCC typically exhibits minimal surface bleeding. In particular, the use
of fine filler materials and viscosity modifying admixtures increases the ability of the paste to retain water
and result in reduced bleeding.
Mix proportioning
Mix proportioning was primarily based on trial mixes; guidance drawn from Japanese and European
publications, experiences, recommendations for SCC, JSCE Manual for production & placement of SCC,
Guidelines for mix design of SCC, by Danish Technological Institute (2008) and European Guidelines for
SCC, EFNARC 2005
Concrete mix M80 adopted at Palais Royale:
Cement 400 kg
Fly Ash 200 kg
Micro Silica/ Metakaolin 40 kg
Sand 968 kg
Coarse Aggregate 676 kg
Admixture 4-5 kg
Viscosity Modifier 0.7 kg
Minor adjustments have been carried out from time to time based on variation in properties of materials and
workability requirements.
Sensitivity to variations
SCC is more sensitive to fluctuations in the total water content than vibrated concrete. Fluctuations in
aggregate gradings and moisture contents have dramatic influence on the stability and fluidity of the
concrete mix. The total water content consists of mixing water and water from the surface moisture of
aggregates. Surface moisture of aggregates are measured by either moisture probes (sensors) or manual
drying tests. Moisture probes can offer real-time result, although accuracy of the results may depend on the
position of the probe in the production chain. However, the maintenance cost can be high. Manual drying
tests are accurate, simple and reliable but take time and cannot offer real time results. SCC is more sensitive
to significant deviations of material quantities. Larger load sizes of concrete lead to better consistency, avoid
batching of small loads of SCC. Batching equipment should be regularly checked for the accuracy. A special
attention should be paid to the accuracy of liquid admixture dispensing/dosing equipment.
Figure 4: Moisture sensor for sand moisture Figure 5: Pressure transducers, flush with form panels
ICI Update - April 2011 23
Formwork
Special formwork imported from Germany is used for columns, beams and slabs. It consists of modular
panels, capable of being combined to form any shape and size. Each panel is light in weight, can be handled
by one technician. The panels are assembled with the help of spring clips and wedges. No bolts and nuts are
used. The formwork facing is similar to plywood and is made of patented synthetic material. The formwork is
capable of unlimited reuses provided they are handled carefully. The choice was based on the excellent
performance during the construction of the tallest building in the world, Burj Khalifa in Dubai.
Figure 6: Patented Formwork
The patented formwork is water-tight, avoids leak of slurry from the SCC resulting in honey-comb free
concrete. The use of foamed plastic sealing strip or moisture curing gunned silicone rubber provides
effective means of sealing joints. Pumping SCC into the form work from underneath is beneficial when high
demands of aesthetics are of importance. The problem with pores and pot-holes also tends to be less when
the concrete has been fed from underneath through valves. Vertical formwork is filled by pumps or crane
skips. . Flat and shallow formwork such as slab and decks are filled from above.
Figure 7: Column Reinforcement Figure 8: SCC Column Surface
ICI Update - April 2011 24
Form work pressures
Reports on form pressure measurements using SCC indicate that a pressure equal or nearly equal to
hydrostatic values will develop at casting rates over 3-5 meters per hour. There is need for controlling the
rate of pour. For SCC, entrapped air is forced out by the moving concrete inside the formwork. SCC should
always be given the possibility to flow for at least a certain distance. Casting all along the element should be
avoided.
Several experiments were conducted and actual formwork pressure under field conditions was monitored.
Though many authorities specify formwork be designed for full hydrostatic pressure, field experiments
indicated pressures higher than those assumed for normal concrete, but lower than hydrostatic pressure.
The rate of pour of the column concrete was regulated to ensure lower concrete pressures. The special
formwork, already procured from MEWA, Germany, did not cater to pumping from bottom up and higher
concrete pressures.
Quality Assurance
Experimental investigations relating to SCC production were aimed at optimizing the process-related
parameters for quality assurance. In this process, mixer-specific details could be defined relating to the
following parameters:
4 dosing sequence
4 dosing accuracy
4 mixing effectiveness
4 mixing time
4 mixing speed
Longer mixing times are required for the production of SCC than for standard concretes. Efficient mixing
times can be achieved by varying both mixing tools and mixing speed.
At Palais Royale a full fledged concrete technology unit has been established, with the necessary testing
equipment and highly qualified staff under the direction of a full time expert, assisted by a PhD concrete
technologist. Concrete mixes are revised from time to time based on the variations in the constituent
materials including admixtures.
E Values assumed in the design are verified from time to time by actual experiments. Before commencement
of SCC pours in columns, a series of mock ups were conducted, in order to verify segregation resistance,
temperature variations between the core and the surface etc. A number of cores were taken and examined.
Necessary corrective action in the method of placement, permissible free fall of concrete etc. has been taken,
based on the mock ups.
Figure 9: Casting of wall with two methods (Gravity filling and pressure)
ICI Update - April 2011 25
Curing
SCC is more susceptible to plastic shrinkage cracking than conventional concrete because of the lack of
bleed water and the he high paste volume. Due to the greater susceptibility to plastic shrinkage cracking,
curing is started immediately after casting regardless of weather conditions. White pigmented curing
compounds are used in Palais Royale. SCC mixes contain higher amount of fines including mineral
admixtures. Thus, there is very little or no bleeding and the concrete will sometimes be more sensitive to
plastic shrinkage cracking. The fresh concrete surface is protected from weather by polythene sheets. Water
curing is started at the earliest.
Working environment
The improvements in working environment when using SCC are substantial on the individuals, on the
society as well as on the technical and economical level. The cost of the society for health care is reduced as
well as the company costs for sick leave, early retirement etc. Legal limitation on time when persons are
subjected to high noise will not be decisive for the length of a working day. It also results in the elimination of
blood circulation disturbance due to handheld vibrators and the strongly reduced noise level. The reduction
of physical loading from lifting equipment and moving concrete is important as well as the increased safety
due to elimination of cables, transformers, vibrators on the workplace and improved verbal communication
between workers. The reduction of the overall noise from the workplace is creating fewer disturbances to
building site neighbours
Concreting
SCC is preferably pumped from below; the pipeline is connected through special valves. However, this could
not be done at Palais Royale and concreting was placed from above. The elimination of manual compaction
makes very high casting rates possible which, in combination with the high flowability, might cause high
formwork pressures. If the concrete is so designed, thixotropic effects can significantly reduce the formwork
pressure. SCC is a complex material with several sensitive interactions between the constituent materials.
Compared to vibrated concrete SCC requires more knowledge, competence and skill of personnel, more
closely controlled properties of the constituent materials and greater care in production and delivery. The
technology also requires greater skill and care in the casting operation. These call for increased focus on
training personnel and on quality assurance issues.
Finishing
Delaying the placement of high-strength SCC results in loss of workability over time, therefore deliveries of
the concrete to the site are scheduled so it will be placed promptly upon arrival. Coordination of delivery
between the batch plant and the placing team is ensured. Yet there are occasions when placement is
delayed, resulting in rapid loss of slump flow, difficulties in finishing operations etc. Finishing operations
are more difficult for SCC due to the thixotropic, sometimes sticky behaviour. Absence of bleeding makes it
even more difficult and finishing operations are related to setting time of the mix in actual conditions.
Appropriate field trials are performed in advance to improve planning and timing of finishing. The
characteristics of the SCC mix, and the skill and timing of the finishers during placement affect the quality
of the surface of slab cast. Conventional tools and ways to finish the upper surface are used This operation
takes a little longer in comparison with the finishing of conventional vibrated concrete. Excellent surface
finish is obtained while using SCC due to excellent flow characteristics, higher percentage of fine aggregate
plus mineral admixtures
Temperature of fresh concrete
Due to the massive column sizes in spite of M80 grade concrete, it was decided to restrict the temperature of
fresh concrete to maximum 30ºC. This has been achieved by adopting measures for hot weather concrete
including use of chilled water for mixing, shading over aggregate stockpiles, etc.
ICI Update - April 2011 26
SCC Issues Addressed
Despite refinements adopted at Palais Royale, several issues are yet to be resolved:
4 Workability: slump flow requirements
4 Free fall of concrete vs segregation
4 Slump loss - production to placement
4 Maximum dosage of PC based admixtures
4 Use of manufactured sand
4 Maximum size of coarse aggregate
4 Formwork pressures: Pressure of Fresh SCC on Vertical Formwork
4 In production from March 2008; 28 days work strength range : 90 - 100 MPa
4 Standard deviation of works cubes ~ 3 MPa
4 Slump flow: insistence on a higher slump flow by field staff.
4 Coarse aggregates: consistency of supply
4 Admixtures: variable quality by same supplier
Credits
Mr. Vikas Kasliwal, the Chief Executive of the Developer, has been responsible for many bold initiatives
including the use of M80 grade SCC.
Testing Fresh Concrete
Slump flow values are tested for each truck mixer load, first as the concrete is discharged from the batching
plant, and then as the concrete is fed into the pump. Any abnormal loss of slump flow is investigated in each
case and corrective action taken by the QA personnel. The variability is reduced in majority of the cases by
coordinating the time of loading; mixes are loaded into the truck mixer in coordination with the placement
crew. In extreme cases of delay, occasionally the mix is rejected.
Testing Hardened Concrete
Works test cubes 150mm size are cast as per IS Standard method except for compaction. Cubes are filled for
full depth of the mould and finished, without any tamping/vibration, and tested at 28 days for compressive
strength. Additional cubes are routinely tested at 56 and 90 days to evaluate strength increase with time.
Based on evaluation over a period of more than a year, it was observed that the M80 concrete used for
columns had strengths in excess of M90 at 56 days and M100 at 90 days. Efforts are on to redesign the
columns above 100 m, taking advantage of higher actual strengths obtained.
Mock up trials
As such high strength SCC is being used for the first time in India, a series of mock up trials were initially
conducted to validate the design & construction aspects:
, Variation in temperature of fresh concrete between the core and the surface
, Permitted free fall of SCC during placement
, Distribution of coarse aggregate over the height of pour
, Quality of surface finish
, Use of 20mm maximum size coarse aggregate
, Verification of E value of concrete
ICI Update - April 2011 27
Mr. Vijay Kulkarni was the second President of ICI to attend ACI Convention and meet many old, present and future benefactors of ICI. Prof R. Jagadish was the first ICI President, when he attended the ACI Convention in San Antonio, Texas in March 2009. At the invitation of ACI, Mr. Kulkarni participated in ACI Convention at
nd thTampa, Fl. held from April 2 to 6 . Dr. Sabnis helped Mr. Kulkarni introduce to as many individuals as he could in these four days of convention. He had discussions with both the President Dr. Ken Hover and Executive VP Ron Berg to set some future milestones in the mutually-beneficial activities for ACI and ICI. It is recommended that at least one officer, preferably President (VP as an Alternate) attend one convention of ACI every year to make meaningful cooperation in many areas.
There are some 100-plus Indians who are working prominently in ACI as volunteers and contribute to its success. They provide a large pool of resources for ICI with their involvement as members with their expertise in different fields. This contribution can be in terms of their attending various seminars/conferences organized by ICI in India.
They can also be instrumental in cementing ties with ACI as they are members of various committees that are useful in Indian scenario of cement and concrete research, design and construction.
There was a dinner meeting at a local Indian Restaurant in Tampa and 40 individuals including few spouses attended it. While speaking before the Indian community, Mr. Kulkarni sought their assistance in sharing of knowledge with professionals in India through the ICI route. He appealed them to join ICI as E-members (available only for foreign members) for $20/year or $50 for three years. These members will get the ICI Update, a monthly ICI journal. Plus, it will give them an advanced notice of many on-going activities in India, if they want to use their trip to India in a more useful manner. Out of some eligible 30 persons, 3 were life members already; one opted to join as Life Member ($250), three at $50 for three years and two at $20.
Mr. Kulkarni thanked Prof Gajanan Sabnis and Prof Kodur for taking painstaking efforts in organizing the dinner.
Indian members in ACI welcome ICI President
Strengthening International Relations
Mr. V.R. Kulkarni, President, ICI at the Dinner Meet Other dignitaries at the dinner meet
Indian Dinner at Tampa
Mr. V.R. Kulkarni, President, ICI and Dr. Gajanan M. Sabnis (2nd & 3rd from left) attending ACI committee meeting with
International partners
Student Chapters
A Guest Lecture on “Construction Project
Management” was organised by the ICI Student
Chapter Oxford Engineering College on
30/03/11. Er.Mohamed Rafikhan, Project
Engineer, Viswakarma Property Developers (P)
Ltd ., Tiruchirappalli, delivered the lecture. In his
lecture, he enlightened the students on the salient
features of construction project management like
ICI Update - April 2011 28
Oxford Engineering College, Trichirapalli
An Industrial visit to RAN India Rolling and
Moulding Pvt. Limited, Tiruchengode, Namakkal,
was organised for the Civil Engineering Students
of the college. Students had the opportunity to
learn the steel making process and to observe the
various stages of steel making like Melting,
Tapping, Moulding Rolling, etc. They also
explained the quality control measures adopted at
all stages of the process.
Lecture by Er. Mohamed Rafikhan, Project Engineer
Visit to raw material (scrap) yard
Steel Rolling Steel Rolling
project planning, structuring the project team,
periodic review, progress monitoring, reporting,
course correction, contingency plan, etc. He
stressed the importance of house keeping at site
and the safety measures to be adhered to. He also
spoke on the job opportunities for the civil
engineers and the students had effective
interaction with the guest.
ICI Update - April 2011 29
A two-day National Conference on Advances in
earthquake Resistant Design and Construction
Techniques was held at Adhiparasakthi
Engineering College, Melmaruvathur, between
April 20 & 21, 2011. This Conference was
organized by the Department under the
auspicious of ICI student chapter of APEC and was
sponsored by CSIR. The conference was
inaugurated by Prof. Dr. M. Sekar, Dean, College of
Engineering, Anna University, on 20.04.11. It was
followed by two technical sessions consisting of
keynote addresses and paper presentations. The
keynote speaker of the first session was Dr. K.
Muthumani, Deputy Director, SERC, Chennai. In
session 1, seven papers were presented. In session
2, the keynote speaker was Dr. M. Neelamegam,
Deputy Director, SERC, Chennai. In this session
also seven papers were presented.
Sessions 3 and 4 were held on 21.04.11. The
keynote speaker for session 3 was Er. P.
Sivaprakasam, Managing Director, Team
Constructions, Chennai. In this session also seven
papers were presented. The keynote speaker for
session 4 was Er. M. Karthikeyan, Managing
Director, MK associates, Chennai. It was also
followed by paper presentation by seven authors.
In each session there was lively discussion by the
participants. The valedictory function of the
conference was addressed by Prof. Dr. K. Ganesh
Babu, Ocean Engineering, IIT Madras. The chief
guests of the inaugural and valedictory function
were honoured by Dr. S. Jayashri, Principal, Prof.
Dr. V. Ramasamy, Dean and Dr. R. Rajasekaran,
Vice-Principal. The welcome address of the
inaugural address was addressed by Prof. A.
Krishnamoorthi and the same for valedictory
f u n c t i o n w a s r e n d e r e d b y P r o f . R .
Venkatakrishnaiah, both conveners of the
conference. The vote of thanks was rendered by
Prof. Dr. A. Leema Rose.
Student Chapters
APEC - Melmaruvathur - Tamil Nadu
Forthcoming Events
Call for Submissions until June 4, 2011
For Details : http://www.iabse.org/press or contact
Sissel NiggelerMarketing and Communications Manager
IABSE ETH Zurich, Hönggerberg HIL E21.3 8093 Zürich, Switzerlandtel: 41-44-633 2647 [email protected]
1. IABSE Photo Contest of Structures 2011
2. ICI-Pune Centre is organising CEMCON 2011
an International Conference & Exhibition on "Construction of High Rise Concrete Buildings (100 Mt & above)" at Sun n Sand,
Pune from 17-18 June 2011.
For details, pl contact :
CEMCON 2011C/o. Arkey Engineering & Foundry Services
Phone : 020-25670808, 25674455
ICI Update - April 2011 30
ICI Update - April 2011 31
ICI Update - April 2011 32
New Members
Individual Life Members
9207 Rameshwar Dayal Singhal Jaipur
9208 Altaf Ahmed Qureshi Indore
9209 S. Geetha Chennai
9210 Vasugi V. Chennai
9211 E. Muthu Kumar Chennai
9212 Achal K. Chowdhary Indore
9213 Archana Keerti Chowdhary Indore
9215 Dr. Hemant Kumar Vinayak Hamirpur
9216 Mallela Malyadri Reddy Guntur
9217 Suresh Rao Marpally Bangalore
9218 Benjamin Michael Ernakulam
9219 M. Sabharimala Coimbatore
9220 Sayinath G. Gaonkar Caranzalem, GOA
9221 Ignatius T. Pereira Salcete, GOA
9222 Abner M. Rodrigues Margao, GOA
9223 Ajay P. Raikar Fatorda, GOA
9224 Shridhar N. Kamat Margao, GOA
9226 S. Thirumavalavan Coimbatore
9227 Deva Kumar E. Vellore
9228 Ashutosh Kumar Pathak New Delhi
9229 Yogesh Sudhakarrao Thakare Amaravati
9230 Jamdade Amol Ganpat Sangli, Maharashtra
9214 Malwa Institute of Science & Technology Indore
9225 TEKLA India Private Limited Navi Mumbai
M.No. Name Place
Organizational Life Members
MARCHMARCH
ICI Update - April 2011 33
Headquarters Election
Notice is hereby given to all members of Indian Concrete Institute that the elections 2011 will be conducted
by postal ballot as per the time schedule indicated below.
NOTICE FOR ELECTION OF OFFICE - BEARERS - 2011
Ocean Crest, 79 Third Main Road, Gandhi Nagar, Adyar, Chennai - 20. Phone: 044 - 2491 2602. 4211 5996 Fax: 044 - 2445 5148
e-rnail : [email protected] ; [email protected] Web: indianconcreteinstitute.org
Indian Concrete Institute
Last date for receipt of nominations : 27.05.2011
Scrutiny of nominations : 30.05.2011
Last date for withdrawal of nominations : 10.06.2011
Despatch of ballot papers to be completed by (if there is contest) : 24.06.2011
Last date for receipt of ballots : 28.07.2011
Counting of ballots and declaration of results : 29.07.2011
Two members of the Governing Council from Chennai will scrutinise the nominations and ballots.
The electorate will be the members of the Institute at serial numbers 1-9107 whose subscriptions for the
period upto March 2011 are valid. Organisational members shall file their nominations / ballots with the
signature of their representative as given in their membership application filed at the Institute. Any change
in representation shall be notified to the Institute in writing, before filling the nominations/ballots.
The election shall be conducted to fill the following vacancies.
President (One)
Vice-Presidents (Four - East, West, North, South)
Governing Council Members (Nine) * Two to represent organisational members from among them elected by all members
* One to represent donor members from among them elected by all members.
* Six to represent individual members from among them, elected by all members.
Nominations may be filed in the proforma.
Nomination papers shall be put in a cover and superscribed :Nominations - Elections 2011" and sent to the
Polling /Returning Officer so as to reach him not later than 5.00p.m. on 27.5.2011.
Indian Concrete Institute
Ocean Crest,
79, 3rdMain Road,
Gandhi Nagar, Adyar,
Chennai - 600020.
R. Radhakrishnan
Returning/Polling Officer
Elections 2011
P.S.: If members wish to table any resolution at AGM 2011, notice may please be given and resolutions
made available to the Secretary General before 30.6.2011 duly proposed and seconded to enable
circulation in advance of AGM 2011.
ICI Update - April 2011 34
Indian Concrete Institute
ELECTIONS 2011
NOMINATION OF OFFICE - BEARERS
Position (President / Vice President / G.C. Member)
1.
Name & Address of nominated person! Organisation
Proposed by
Name and Address
Seconded by
candidate
2.
3.
Name and Address
Nomination agreed to by the 4.
(Signature) Memb. No.:...................................................................................
:...................................................................................
....................................................................................
....................................................................................
(Signature) Memb. No.:...................................................................................
:...................................................................................
....................................................................................
....................................................................................
:...................................................................................(Signature) Memb. No.
....................................................................................
....................................................................................
:...................................................................................
:...................................................................................
Nominations shall reach the Returning Officer", in a cover superscribed "Nominations Elections
2011" before 5.00 p. m. on 27.05.2011.
A short bio-data of the candidate in not more than 100 words highlighting the contributions to
the profession and lei should be enclosed.
Use one nomination form per candidate per position
5.
6.
R. Radhakrishnan Polling / Returning Officer Elections 2011 Indian Concrete Institute Ocean Crest, 79, 3rd Main Road, Gandhi Nagar, Adyar, Chennai - 600 020
*
Note : Organisational members should sign these papers through their authorised representatives as
indicated in membership application form or as modified and notified to ICI Headquarters before
filing the nomination
Headquarters Election