AKNOWLEDGEMENT:

WE EXPRESS OUR DEEP SENSE OF GRATITUDE TO MR. SHAKIR SIDDIQUE (DIRECTOR DEVELOPMENT HUMAN RESOURECE) FOR ENCOURAGING US TO DO INTERNSHIP AT THIS ORGANIZATION, PARAGON CONSTRUCTORS (PVT) LTD.

WE ARE VERY MUCH THANKFUL TO MR. SYED HASHIM (GENERAL MANAGER) FOR HIS VALUABLE GUIDANCE, KEEN INTEREST AND ENCOURAGEMENT AT VARIOUS STAGES OF OUR INTERNSHIP PERIOD.

WE EXPRESS DEEP GRATITUDE TO MR. HARIS (PLANNING ENGINEER), MR. UMAID (SITE ENGINEER), MR. FARHAN (SITE SUPERVISOR) AND MR. IRSHAD-UL-HAQ (NESPAK) FOR THEIR GUIDANCE, ENCOURAGEMENT, SUGGESTIONS AND VERY CONSTRUCTIVE CRITICISM WHICH HAVE CONTRIBUTED IMMENSLY TO OUR LEARNING EXPERIENCE.

MINHAL HAIDER

ARSALAN ASHRAF

MOHAMMAD BILAL

ABDUL BASIT

STAKESHOLDER:

Project Client : Emaar Giga karachi ltd. Project Contractor : Paragon constructors (pvt) ltd. Project Consultant : Nespak (pvt) ltd.

PARAGON :

Paragon Constructors is the leading company of PAKISTAN in the construction field as all the mega projects going on in Pakistan, such as Lucky one shopping mall, Bahria town icon hotel tower, Bahria opal tower, Emaar giga Coral towers, UBL head office building,Creek view & terrace and others are heading under their expertise. Since the company has a long history of completing their projects within in the specified timeline, now they are heading to achieve another historical landmark of completing the “EMMAR CORAL TOWER” project in the upcoming year. Such a progressive attitude of the company reflects their determination and dedication towards their profession.

EMAAR :

Emaar is a well known construction company with its origin in Dubai. Irrespective of whether a development project is residential or commercial, it has a vast history of creating something out of the box and jaw dropping. Burj kalifa of Dubai. It is an apparent evidence of their determination, innovation and construction skills.

Recently, Emaar has its greatest stake in 48 towers named as Coral Towers in Pakistan which are located at sea shore. Project is quite unique as the new construction methods are introduced for the first time in the industry. In order to complete the project in time, Emmar has facilitated the contractor to maximum.

NESPAK

Nespak is a prominent consultant company of Pakistan assisting and facilitating millions by providing their services in water management, high rise construction, transportation etc. Since its formation, NESPAK has made sure that all necessary requirements are fulfilled regarding safety and durability. In order to prevent any mishandlings and disorganization expert engineers are hired for the inspection purposes.

PROJECT DETAIL:The project comprises of 48 towers out of which two are named as CORAL TOWERS which are in under progress. According to the direction of each tower they are

designated accordingly as North tower and South tower. Podium connects both the towers and gives an elegant look from the distance. Both the towers are symmetrical in shape and dimensions. Each tower consists of two basements, one mezzanine floor and 26 ordinary floors. There are 9 columns, 9 shear walls and two cores (lift core and stair case core). The projection is provided after every 3rd floor which works as a shade against the scorching sunlight. A single floor is completed in 18days as per the policy of the contractor but it may vary due the delay in the arrival of shipments, environmental hazards or loss of material.

FORMWORK OF SLABREINFORCMENT OF SLABCONCRETEING OF SLABREINFORCMENT OF COLUMNS AND SHEARWALLPOST TENSIONING OF SLABFORMWORK OF COLUMN AND SHEAR WALLCONCRETING OF COLUMNS AND SHEARWALLSREINFORCEMENT OF COREWALL18 DAYS CYCLE OF A SINGLE FLOOR

FORMWORK OF SLAB:

The cycle begins with the placement of the scaffolding components such as horizontal props, vertical props and main beams over which the plywood deck is placed so that the slab reinforcements can be placed as per the drawing.

REINFORCEMENT OF SLAB:

A mesh of the slab reinforcement comprises of different types of bars. U-bars are used to hold the reinforcement wherever the beams lie. Punching shear reinforcement is used to provide strength against the negative moment develop at the support. Chairs are used to provide the designed height to the tendons so that it can balance the moments develop in the slab. A small U-shaped reinforcement is used to hold the trumpet enclosing the strands during stressing.

CONCRETING OF SLAB:

Concreting of slab is the most critical and important part of the cycle. It takes almost 7 to 8 hours for the complete concreting of the slab, which is done through the

Reinforcement used for holding strands on dead Chairs under the re-bars Slab reinforcement mesh

Formwork of slab

placing boom being adjusted as the floor level proceeds. Mostly this activity takes place at night to avoid the rapid setting time.

REINFORCEMENT OF COLUMNS AND SHEARWALLS:

Once the concrete is set the labors start the work on the reinforcement of columns and shear walls. Proper lap distances between bars, placement of stirrups and placement of vertical bars are laid as per the drawing so that the consultants gives the positive IR and work may proceed further.

o SHEAR WALL:

The primary purpose of the shear wall is to resist the lateral forces being developed below or above the ground surface. These lateral forces include seismic force, which is maximum at the ground surface and wind pressure, which is maximum at the higher altitude. Shear wall distributes the load developed by these forces and saves the structure from any significant failure.

POST TENSION SLAB:

The important thing about this project is post tensioning slab which is introduced for the first time in the Pakistan. The function of post tension slab is to reduce the thickness of slab, reduction in self weight of the building, reduction in steel uses in

Reinforcement of column Reinforcement of shear wall

slab, since all of the tensile forces develop in the structure is taken by the tendons. It reduces or eliminates shrinkage cracking-therefore no joints, or fewer joints, are needed.

Post tensioning wires has two ends: Live end wires Dead end wires

Live end wires are those which are free on both sides of the slab therefore stressing can be done from both ends. Dead end wires are those which are free from one end and discontinued at mid span of slab near the supports where onion of the wires is made to prevent the slippage of the stands during stressing.

The procedure of post tensioning begins with the replacement of temporary blocks with the shear blocks in the trumpet. Shear blocks are designed according to the number of strands in the tendon. Threaded wedges are provided in the holes of the block so that during the stressing, strands do not move back and stay elongated. The stressing of tendon is done through the hydraulic jack attached with the hydraulic pump. In the beginning the 50% of the designed pressure is applied then in the second round of stressing the pressure is increased up to 100%. During the stressing procedure if the wire breaks then the threaded coupler is used. The strands are threaded and fixed on both ends of the coupler for the continuity.

Shear block with wedges

FORMWORK OF COLUMNS AND SHEAR WALLS:

Although the formwork of the slab and shear wall is carried out side by side with the post tensioning of the slab but special attention is laid on the alignment of the formwork for which heavy objects are tied and hanged. The measurement is taken from the face of the form work to the string to check the alignment.

CONCRETING OF COLUMNS AND SHEARWALLS :

Columns and shear walls are concreted through the buckets lifted up by the cranes. Special attention is paid during the concreting in order to avoid the danger of breaking of formwork due to the weight of the concrete.

Formwork of column

Live end of tendon Dead end of tendon

REINFORCEMNT OF COREWALLS:

Since the reinforcement of the core is quite heavy and complicated therefore special attention is paid during the placement and the alignment of steel. Here on site there are two core pits, one is for the stairs and other one is for the elevators.

CONCRETING OF CORE:

In a high rise building majority of the load is taken by the core therefore, its strength and durability for the entire structure is very crucial. Once the consultant give the positive IR to the core reinforcement and formwork alignment then it starts the concreting of the core which is done through the placing boom.

OTHER ACTIVITIES DURING CONSTRUCTION:

Reinforcement of core walls

Concreting through bucket

GROUTING:

It is a mixture of cement, water and FOSPAK 337 chemical, used as a bonding agent between the tendon wires and corrugated sheet. It prevents the danger of corrosion in the strands and develops the homogeneity between the tendon and the concrete.

BLOCK MASONARY

Here in this project hollow blocks are used instead of solid concrete blocks. The reasons for selecting hollow blocks over solid concrete blocks are:

It reduces the building cost Economically friendly and cheap rates The acoustic system of the rooms becomes good It maintains the thermal balance It reduces the labor cost

The blocks are prepared on site. The materials used to make the blocks are:

½ cement bag 3 trolleys of aggregates and sand Water

The material is mixed in a mixing machine and transported through the wheelbarrow to the block making machine. Once the block is put into its size curing is done. These blocks are later on supplied to the site where they were used in making partition walls. During the placements of the blocks alignments is checked through the bob to maintain the uniformity of the blocks.

PLASTERING

Plastering is done over the block masonry for the uniform and plain surface. The thickness of plaster varies at some walls and ceilings due to uneven surface level. The

Block masonry Block masonry

minimum thickness of plaster is 0.75in and maximum is 2in. The material used in making a durable plaster is cement and sand mixed in the ratio of 1:4. A layout for the plaster is made on the wall and on the ceiling so that the uniformity in the thickness is maintained. Plastering at the joints is discontinued so that the cracks develop on the ceiling do not transfer at the plastering layer of the wall.

CURING OF CONCRETE:

Curing is done so that the temperature and the moisture content of the newly placed concrete remain stable. Generally curing is done for 7 days but here early strength concrete is used therefore the curing period is reduced up to 3 days.

chippingis done for plastering

Layout of plastering

Discontinuity at the top and bottom plastering

BATCHING OF CONCRETE:

Batching of concrete is a process whereby cement is mixed with the coarse aggregate and fine aggregate as well as with the water. Concrete batch plants are devices used to mix the various ingredients to form concrete. Here on site the plant used for batching is Central Mixed Plant.

The concrete batch plant can be categorizes into 4 parts:

1- Aggregate feeding2- Cement feeding3- Water and admixture for mixing the material4- Conveyance and storage

The process begins with the mixture of aggregate of size 10mm and 20mm along with the sand which is pushed forward by the operator into the bucket having a capacity of 1m3. The bucket is lifted up by the conveyor belt and drop the mixture into mixing machine where it get mixed with the water supplied through the pipe and cement supplied through the silos of capacity 100, 110 and 130 tons. The TM underneath the mixing machine hopper receives the mixture into the rotating drum mounted on a transit mixture. It takes just 17 seconds in this entire process.

The concrete prepared in the plant is of the following strength:

Lean concrete 2000psiPile 5000psi

Curing of slab

Columns 5000psiShear walls 5000psiPT slab 5000psi

The admixture used for the slab concrete is R-850 which works as an accelerator i.e. increases the setting time of concrete.

PILE LOAD TEST:Piles are used where the bearing capacity of the soil is too weak to carry the structural load. Generally piles are of two types, the one is friction pile which is used where hard strata is not available at sufficient depth so the pile uses the friction of the surrounding soil and get stuck within it. The other is end bearing pile which is used when the hard strata is available at required depth. The pile rests on that hard strata and transfers the structural load. Since the strata of the soil under the pile sometimes varies which results in the differential settlement. In order to avoid the danger of differential settlement some tests are conducted to ensure the safety of the future structure.

REACTION PILE METHOD:

In this method design load of 590 tons and maximum working load of 890 tons is applied on the index pile. The load is applied through the hydraulic pump attached with the heavy girders supported by the two supporting piles. Criteria can be carried out by loading and unloading process. If the rate of settlement is greater than 0.25mm/hr then test will go for 24 hours.

Load is applied in a cyclic manner i.e. 25%, 50%, 75% and 100% of design load which is 590 tons; this cycle is reversed on an unloading condition. A same criterion is applied at max load which is 890 tons.

Pile load test Gauges measuring the settlement

EQUIPMENTS USED IN CONSTRUCTION:

SELF ERECTING TOWER CRANE:

Self erecting tower crane is used for transferring of materials such as steel, plywood deck, hydraulic pump at high floors. The bucket used for concreting the shear wall and columns is also carried by such crane. Its maximum load carrying capacity is 4 to 5 tons and has a jib length of 40 m.

TRANSIT MIXTURE:

Transit mixture is used for transferring concrete from the batching plant to the construction site. Its carrying capacity varies according to the demand on site. Here the TM. Of 9m3 is used.

PLACING BOOM

Placing boom is used for concreting the slabs and the corewalls. It is a combination of large pipes operated hydraulically. The main pipe goes down to the last floor

Tower crane

Transit mixture

where it is attached with the static pump. When the TM pours the concrete it is pushed forward by the static pump.

STATIC PUMP

A static pump is a machine used for transferring concrete at higher floors by applying a high pressure on it. This pump is used in large construction projects where high volume of concrete is required constantly. It applies the hydraulic pressure of 10 to 20 MPA while pushing forward the concrete through the pipe line. The maximum voltage of the pump is 380volts and current is 100 ampere.

HYDRAULIC JACK AND HYDRAULIC PUMP:

Placing boom

Static pump

It is a device used for stressing the wires. It consists of the meter which shows the applied pressure value on application. The meter is filled with fluid so that needles do not get disturbed due the air pressure.

Hydraulic jack