HOLLOWCORE

Abu Dhabi (Head Ofce) Dubai: Iraq:

P.O. Box 44495, ICAD1 P.O. Box 19302 DIP. Hay Alwahda - Aqaba Bin Na
Tel: +971 2 550 2044 Tel: +971 4 885 1033 Sq. District 904, St. # 15
Fax: +971 2 550 2344 Fax: +971 4 885 1016 Bldg. 72, Baghdad.
Tel: +964 7708 957 173

Email: estimation@gulfprecast.ae website: www.gulfprecast.ae

 HOLLOWCORE

Introduction to Hollowcore 03

Advantage of Hollowcore Slabs 04

Production Process of Hollowcore 07

Typical construction details 09

Typical Hollowcore openings 11

Typical Projects 12

Typical projects during

construction 16

CONTENTS

Gulf Precast 2
 INTRODUCTION TO HOLLOWCORE

INTRODUCTION TO
HOLLOWCORE
Hollowcore slabs are precast prestressed concrete elements extensively used for floor, roof
slabs and wall panels. The success of this precast product is owing to the combination of
high efficiency of design, automated production technology resulting in remarkable low
price, versatility in the selection of unit depth and capacity, in addition to its ready-to-paint
smooth soffit as well as its high quality and durability.

The automated manufacturing process uses a combination of dry mix concrete and
shear compaction, which considerably reduces the consumption of water and
concrete if compared to conventional process. This key sustainable advantage is
recognized by governmental authorities (such as Dubai Municipality, Abu Dhabi
Municipality, and Estidama / Leed).

Hollowcore is manufactured using long line extruders which form continuous

cores running through the slabs. The primary purpose of these cores is to
decrease by 40% to 50% the weight of the slabs, which leads to significant
savings in the rest of the members of the building construction. They are
also used as pre-existing conduits to place electrical cables and pipes,
thus reducing even further the overall construction time.

Hollowcore slabs from Gulf Precast are used horizontally in all type of
structures such as villas, buildings, commercial and industrial
structures, hotels, schools, shopping centers.

They may even be used vertically, as wall panel partitions, in

industrial structures or in boundary walls.

3 Gulf Precast
 ADVANTAGES OF HOLLOWCORE

ADVANTAGES
OF HOLLOWCORE
Advantages of Hollowcore Slabs are numerous:
Remarkably lower price compared to other systems.
Automated production under strict Quality and Safety Control.
Longer span and greater loads than conventional slabs of the
same thickness.
No need for propping and scaffolding.
Under side immediately ready for following trades.
Maximum design flexibility.
High strength, lightweight, durable structure.
Superior fire resistance.
Superior earth quake resistance.
Preexisting longitudinal holes that can be used as conduits.
Speed and ease of construction.
High thermal insulation properties.

To further increase their strength, the slabs are reinforced

longitudinally with a number of wire steel strands (the number and
diameter of which are calculated during the engineering stage),
which are prestressed for optimal resistance.

Hollowcore is the product of choice in structures that require sound

barriers between floors, excellent fire and earthquake resistance,
heat insulation characteristics, long spans, and is therefore widely
used in hotels, schools, multi-storey car parks, high rise buildings
and upscale residential and commercial complexes.

Hollowcore slabs are available in a range of seven depths:

150, 200, 265, 320, 400, 450 and 500mm slabs. The
longest span can reach up to 18m.

Abu Dhabi International Airport

Khalifa Mosque at Al Falah Community

Gulf Precast 4
 ADVANTAGES OF HOLLOWCORE

Depending on the project requirements, in particular the desired span and loading performance, Gulf
Precast Engineering department proposes and designs the most adequate and economical
Hollowcore solution for the project.

Factory produced by automatic extrusion:

Hollowcore slabs are manufactured in the factory on 125 long beds
using automatic extruders, combining high output, low manpower and
superior quality products.

Rapid construction:
Hollowcore slabs are cut to fit the requirements before leaving the
factory, thus allowing simple fast erection on site.

Immediate work deck:

Hollowcore slabs provide an immediate solid work deck for other
trades. After grouting the shear keys, the slabs can support
construction loads up to full design capacity of the floor.

No formwork or Propping:
Expensive formwork and temporary props are eliminated, giving free
uncluttered space with vastly improved access within the work site.

Reduced on-site labour:

Only a small erection crew is required to install as much as 600 square
meters per day. The time of tradesmen on site is kept to a minimum.

Efficient light weight section:

The Hollowcore and prestressing impart a lightness and strength to
the slabs which reduce the dead load on the floor. The depth of floor
and the strand pattern can be varied at minimum cost to suit the span
and load requirements.

Design flexibility:
Hollowcore slabs are compatible with most building materials
including masonry, concrete and steel. Slabs can accommodate
most building requirements including openings, angles and
cantilevers.

Al Wahda Mall, Abu Dhabi

5 Gulf Precast
 ADVANTAGES OF HOLLOWCORE

Durability:
Concrete quality meets the durability requirements of the most
stringent standards. Strand cover may be varied to suit particular
exposure classifications.

Long span:
Hollowcore slabs can accommodate long spans, resulting in flexible
open space with fewer beams, walls and supporting columns. Clear
spans of up to 18m can be obtained economically.

High load capacity:

Hollowcore slabs can handle the heavy loads required in most
factories, warehousse and storage buildings without increasing floor
depths or adding multitudes of beams and columns.

Fire resistance:
Fire resistance periods up to 240 minutes (4 hours) can be provided to
meet building code requirements.

Sound insulation:
The low sound transmission property of Hollowcore floors reduces the
amount of noise transmitted through floors and ceilings. Sound
Transmission Class ratings as specified in building codes can be met
for variety of occupancies.

Prefinished ceilings:
Exposed Hollowcore soffits can be painted directly or spray coated to
provide attractive ceilings. Alternatively ceiling tiles can be applied
directly or suspended ceiling simply installed.

Service cores:
Longitudinal core holes in floor slabs can be used as service ducts for
concealed services such as plumbing, electrical and telephone cable.
Breakouts can be drilled as required.

Gulf Precast 6
 PRODUCTION PROCESS OF HOLLOWCORE

1. Bed Preparation:
The prestressing steel beds are cleaned
thoroughly and slightly oiled to allow easy
stripping of concrete after casting. The
steel strands are then laid and fixed at
both ends.

2. Stressing the Strands:

The-7wire strands are stressed one
by one, under strict Quality Control.

The stressing forces, number of

strands and their position are all
determined according to slab
design.

3. Casting and Automatic Extrusion:

In order to meet the high durability and
strength requirements for Hollowcore, top
quality concrete (high early and ultimate
strength, zero slump, high durability) is
batched and transported to our
state-of-the-art extruder which compacts it,
then extrudes the Hollowcore section
continuously along a 125m bed.

7 Gulf Precast
 PRODUCTION PROCESS OF HOLLOWCORE

4. Detensioning and Cutting:

18 hours later, when quality checks
confirm that required concrete strength
has been reached, strands are
detensioned and the precast prestressed
concrete bed is cut into different
elements according to design.

5. Storage and Curing:

Hollowcore slabs are then stored and
cured in the yard according to quality
procedures and up to the specified
time.

6. Transport to Site:
Transport is done by flat trailers, with
Hollowcore slabs stacked
horizontally, supported by timber
planks and well secured to avoid
transport damage.

7. Erection:
Hollowcore slabs are lifted from the
trailers or stock on site by a special
spreader beam and lifting belts, to
ensure that no overstressing or
damage occurs during erection.

Up to 600 m2 of Hollowcore slabs can

be erected by one team in one day,
making Hollowcore one of the fastest
construction systems available.

Gulf Precast 8
 TYPICAL CONSTRUCTION DETAILS

SSL. C.I.S. TOPPING T8 @200

HOLLOWCORE SLAB 15 15 HOLLOWCORE SLAB

70 70

C.I.C. BEAM

HOLLOWCORE SLAB CONNECTION DETAIL

1
1200

H.C.S. 70 70 H.C.S.
C.I.S. BEAM

1200

H.C.S. H.C.S.
1200

H.C.S. H.C.S.
1

SECTION PLAN

CAST IN SITU T8 @200

TOPPING

1200
HOLLOWCORE SLAB
13mm PRESTRESSED
STRANDS
SECTION 1 - 1

CAST IN SITU T8 @200 CAST IN SITU

GROUT
TOPPING TOPPING

X X

35 35
T12 LINK HOLLOWCORE CLAB
HOLLOWCORE SLAB

C.I.S. BEAM

TYPICAL HOLLOWCORE SLAB CONNECTION DETAIL

9 Gulf Precast
 TYPICAL CONSTRUCTION DETAILS

C.I.S. BEAM Y

500 500 T12 LINK

CUT OUT TO BE GROUT

AFTER ERECTION

1200 CUT OUT TO BE GROUT

AFTER ERECTION
T12 LINK

35 35
HOLLOWCORE SLAB Y HOLLOWCORE SLAB

SECTION X - X

CAST IN SITU GROUT T8 @200

TOPPING

1200

HOLLOWCORE SLAB

SECTION Y - Y

JOINT GROUT

JOINT GROUT
20

CONCRETE BEAM

TAMPING
3MM - SEALANT NOT REQUIRED

SLAB JOINT (SHEAR KEY)

SUPPORT ON CONCRETE BEAM

JOINT GROUT UPSTAND CASTED EITHER

BEFORE OR AFTER SLAB ERECTION JOINT GROUT
20

TIE REINFORCEMENT BARS IN SLAB JOINT STUDS WELDED TO BEAM

CONCRETE BEAM
TAMPING

SUPPORT ON STEEL STRUCTURE

SUPPORT ON CONCRETE BEAM

Gulf Precast 10
 TYPICAL HOLLOWCORE OPENINGS

HC 26-103-F2
T8 STEEL CONNECTED BETWEEN
TWO HOLLOWCORE SLABS HC 26-103-F2e

6
(TO BE DONE AT SITE)
C.I.S. TOPPING HC 26-103-F2f
T8 @ 200

430
430
HC 26-103-F2g 655
70

100

HC 26-103-F2h

6
265

HC 26-103-F2k

AS PER OPENING SIZE HOLLOWCORE SLAB

STRANDS

Typical opening support detail with saddle

A98 MESH T8 STEEL CONNECTED BETWEEN

C.I.S. TOPPING
TWO HOLLOWCORE SLABS
( TO BE DONE AT SITE)

375 375
1200 1200

150 x 10 EQUAL ANGLE SADDLE

Typical opening support detail with saddle

11 Gulf Precast
 TYPICAL PROJECTS

TYPICAL
PROJECTS
Ruwais Housing Complex

Al Wathba Insurance Building

Al Rawdhat Building

Al Barari Villas, Abu Dhabi

Erection of Hollowcore at Emirati Housing Development, Al Ain

Al Qalaa Villas

22 Villas for Sheikh Hamdan Bin Zayed

Gulf Precast 12
 TYPICAL PROJECTS

Paris Sorbonne University during construction

Paris Sorbonne University, Abu Dhabi

IKEA, Abu Dhabi

Dubai Mall

Dubai Mall during construction

Dubai Garden Apartments

13 Gulf Precast
 TYPICAL PROJECTS

Abu Dhabi Theatre

Abu Dhabi Financial Centre

MAN Showroom, Jebel Ali, Dubai

Al Falah Community, Abu Dhabi

MAN Showroom, Jebel Ali, Dubai

Al Falah Community during construction

Workers Village, Abu Dhabi

Gulf Precast 14
 TYPICAL PROJECTS

Industrial City of Abu Dhabi

Etihad Interim Terminal 3 , Abu Dhabi

15 Gulf Precast
 TYPICAL PROJECTS DURING CONSTRUCTION

Gulf Precast 16
 TYPICAL PROJECTS DURING CONSTRUCTION

17 Gulf Precast
 HOLLOWCORE

Abu Dhabi (Head Ofce) Dubai: Iraq:

P.O. Box 44495, ICAD1 P.O. Box 19302 DIP. Hay Alwahda - Aqaba Bin Na
Tel: +971 2 550 2044 Tel: +971 4 885 1033 Sq. District 904, St. # 15
Fax: +971 2 550 2344 Fax: +971 4 885 1016 Bldg. 72, Baghdad.
Tel: +964 7708 957 173

Email: estimation@gulfprecast.ae website: www.gulfprecast.ae