The Halfen-Moment Group of companies started its operation in Malaysia, supplying mechanical couplers to construction sites, as a cost effective alternative for conventional splicing. One of our first iconic projects was the Petronas Towers. Since then, the group has been expanding rapidly and today the MOMENT® coupler is a well established brand in the market.
With headquarters in Malaysia, serving as the central hub, and being supported by its subsidiaries in Singapore, Philippines and India together with invaluable partners in other markets, we have positioned ourselves as a leading building products player with an established and extensive network throughout Asia and the Middle East. Long term partnerships with our customers motivate us to continuously extend our product offering to more reinforcement and construction accessories. Our product range is used from small scale residential projects to large development projects in infrastructure, high rise or commercial construction. Our specialized teams are there to provide technical information and to ensure consistent and high quality solutions. Since 2012, the Halfen-Moment Group has been part of CRH plc, a Global Fortune 500 company, with an annual turnover in excess of €27 billion. Thanks to CRH plc, The Halfen-Moment Group has access to financial resources, innovative products and technical expertise from around the world in order to support its continuous development. Being part of a stock quoted company, we are aware of our global, local and social responsibility. Leading our business with integrity is our daily credo
Quality
Providing quality assurance & safe products through excellent
service, is one of the top principles of Halfen-Moment Group.
Being part of CRH plc., we strive to adhere to the most stringent
group quality policies. Our in house team is conceived daily
with quality checks to ensure the highest quality is offered. Our
quality management system is accorded by the ISO 9001 :
2008 accreditation.
Outstanding Support
technical support, statistical calculation to product installation
performed by our qualified engineers & specially trained staff.
MPT PRESTRESSING AND POST TENSIONING SYSTEM
is designed and tested to meet stringent standards, the range of buildings and civil engineering applications includes:
• Commercial and residential high rise
• Retails shopping centers
• Load transfer structures
• Slabs on grade
• Silos and reservoirs
• Bridges
• Ground anchoring and earth retaining.
MPT FLAT SLAB SYSTEMS
MPT flat slab system is normally adopted for bonded tendon. The strands are individually gripped in one triangle flat anchor head unit and transmit their pre-stressing forces by means of flat type anchor plate casting unit. The strands are stressed individually by means of a mono strand jack. The strands are contained in one flat duct (duct size: 20mm x 70mm) which is made of corrugated galvanized metal. To ensure corrosion protection and to give adequate bond strength, the tendons are filled with suitable cement grout mix after complete stressing of the strands. Facilitating of concrete placing due to the absence of tendons in the webs, and ease for placing tendons.
MPT DEAD END ANCHORAGE
Stressing of a tendon from one end only, to which the load is applied
MPT MULTISTRAND ROUND SYSTEMS
A method of reinforcing and pre-stressing concrete, masonry and other structural elements. Today, it is used for a wide range of applications including office buildings, condominiums, hotels, parking structures, slab-on-ground foundations, ground anchors, storage tanks, stadiums, silos, and bridges.
The systems are normally adopted for bonded tendons. The tendons consist of a bundle of strands with a nominal diameter of 0.5” (12.7 mm.) or 0.6” (15.2 mm.). The number of strands per tendon can be from 4 strands up to 42 strands of diameter 0.5” or 31 strands of diameter 0.6”. The strands in the tendons are contained in one round duct which is made of corrugated galvanized metal.
The strands are individually gripped in one anchor head unit and transmit their pre-stressing force by means of anchor plate casting unit. For each anchor size, special spiral reinforcement is provided at the anchor plate casting to give adequate splitting reinforcement for bustling stresses developed at the anchorage zone. The strands in tendon are stressed simultaneously by means of a multi strand stressing jack from capacity 1,100 KN up to 5,000 KN. The strands can also be stressed individually by means of mono jack.
Post-tensioning is a method of reinforcing (strengthening) concrete or other materials with high-strength steel strands or bars, typically referred to as tendons.
Post-tensioning applications include high rising buildings, office and apartment buildings, parking, structures, slabs-on-ground, bridges, sports stadiums, rock and soil anchors, and water-tanks.
In many cases, post-tensioning allows construction that would otherwise be impossible due to either site constraints or architectural requirements.
MPT T13 ANCHORAGE
MPT T15 ANCHORAGE
STRANDS
The strands are formed with seven steel wires: one central wire around which the other six are wrapped. They are generally supplied already stabilized (low relaxation) and certified according to the regulations by an independent laboratory, in coils weighing kg 2500-3000. Usually greased or waxed strands, incased in a HDPE sheath, commonly called unbounded, are used to manufacture the external tendons. Such Strands can be hot-dip galvanized too.
POST TENSIONING JACKS
The jack is placed over the strand and when tensioning starts they are automatically and simultaneously engaged in the pulling head of the jack. Once the required elongation and load are reached the lock-off device of the jack can be activated to house the wedges in the anchor head uniformly. The tensioning can be accomplished in more steps based on the elongation of the cable. A tensioned cable can be released using proper releasing devices
GROUTING
Cables are normally grouted after sealing their anchorages with concrete or, if required, using proper grouting caps. Before grouting the tendons, they should be flushed to ensure that no obstruction would impede the flow of the injected grout. The sandless grout, injected using MPT grouting pump, is kept under pressure throughout curing. The water-to-cement ratio is kept as low as possible. Usual proportion of ingredients are: 36-38 liters of water, 100kg of cement and addictive according to the instructions of the manufacturer. The mix produces 72-74 liters of grout
Components of Post Tensioning Slab
1. Ducts
Thin sheet metal pipes with claw coupling or welded overlapped seam supplied in lengths of 5 and 6 m respectively are used as a standard. Ducts are connected to each other by an external screw coupling and sealed with PE tape. Plastic ducts are also available in the market these days which are water tight , frictionless and fatigue resistant
2. Tendons
The basic element of a post-tensioning system is called a tendon. A post-tensioning tendon is made up of one or more pieces of prestressing steel, coated with a protective coating, and housed inside a duct or sheathing.
The prestressing steel is manufactured as per the requirements of ASTM A-416 and typical strand sizes are 0.50 and 0.60 inch in diameter. A typical steel strand used for post-tensioning will yield about 243,000 psi. In contrast, a typical piece of rebar will yield about 60,000 psi.
3. Anchors
Anchors are used to anchor the tendons into the concrete while terminating or joining two tendons. Main function of anchorage is to transfer the stressing force to the concrete once the stressing process is completed.
Construction of Post Tensioned Slab
- The installation of post tensioning tendons in the concrete and stressing it requires skilled labour and a personnel who are certified in doing the tensioning works.
- The tendons are laid down along with the conventional rebars. The position of laying of the tendons is decided by the engineer. These tendons are encased in plastic or steel ducts so that they do not come in contact with the water in concrete.
- One end of the tendons are anchored with the help of anchor and the other end is left open with plastic pocket former, where the tendons are stressed. Couplers are used in between if any construction joint is formed.
- Concrete is poured and the alignment of these tendons are taken care of so as to let their positions unaltered. Once after the concrete has achieved its 75% of strength , that is around 20 – 23 days, these tendons are stressed with the help of stressing jacks.
- The tensioning is done to a force equal to 80% of a strand’s tensile strength. For a typical ½-inch grade 270 strand, the strand is tensioned to a force of 33,000 pounds. As the tensioning comes into effect, the steel gets elongated, and the concrete is compressed.
- When the proper tensioning force is reached, the prestressing steel is anchored in place. The anchors are designed to provide a permanent mechanical connection, keeping the steel in tension, and the concrete in compression.
- The extra tendons that are left out at one end are trimmed and non shrink grouting is put in the anchor pocket.
Advantages of Post Tension Slab
1. Architectural Benefits
Post-Tensioned Slab has an advantage over others as it makes a very efficient base for floor design with thin slabs and columnless spaces in larger spans. It provides an architect the freedom to work freely with his designs.
2. Commercial Spaces
Post-tensioning results in thinner concrete slabs making the valuable savings in floor to floor height available as additional floors.This can provide extra rentable space within the same overall building height.
3. Reduces Deadload
As the post-tensioned slabs have lesser thickness, the quantity of concrete and reinforcement used is reduced upto 20% – 30% when compared to conventional concrete slabs.
4. Structural Durability
Post-Tensioned slabs show reduced cracking, improved durability and lower maintenance costs. Their deflection can be controlled by varying the amount of post-tensioning to balance any portion of applied loads immediately after stressing.
5. Popularity
The demand for Post-Tensioned slabs, throughout the world, continues to increase because of the significant benefits for developers, architects, engineers, contractors and end users.
