Eco Voided Slabs

Build Faster. Lighter. Economical. Flexible. Greener.

Slab System

EVOS, the best on the world market “Slabs Void Former” system, developed by CME International, is a superior Voided Slab solution, newly patented, with a registered trademark in over 50 countries, accredited by the International Code Council (ICC) and many international bodies, manufactured in 3 countries in highest quality and standards. Evos provides easy handling, product stability at site and a perfect match between theoretical designs and actual implementation at site.

The concept of EVOS is very simple, while keeping on the traditional nature of the solid concrete slab as a static and cast in situ slab, and without any complications and without compromising the bottom steel and concrete cover; Evos replaces the non-working concrete inside the slab (between the bottom and top steel reinforcement) with voids.

The immediate result of the concrete displacement is of course slabs weight reduction. Evos slabs are in average 30% lighter than solid slabs and 15% lighter than posttensioned slabs. But the benefit is achieved when reflecting reduction in slab weight on vertical elements and foundation steel reinforcement and concrete quantities.

Void formers can be used in various types of concrete structures such as: commercial ,residential , parking, malls, factories, hospitals etc. . .

Void formers have an Oval Cylindrical shape. Void formers are made of recycled plastic materials and have a wide range of heights, depending on the structural design requirements, based on slab spans, loads, arrangement, …….

EVOS section has no sharp edges due to VF shape. No concentrated stresses.

Improved vibration resistance.

EVOS positioning steel cage consists of only one factory made piece, used to integrate void formers andmake spacing between them. Which leading to fast assembly, stability on slab, very easy distribution and handling. Steel cages are positioned between the bottomand top reinforcement layers in the slab's cross section where they also serve as supporting cages for the top steel. Steel Cage advantages:

1. Increased stability of void formers’ bodies inside Steel Cages with very limited internal movement 2. Dramatically improved strength and stability to support normal foot traffic and reinforcement bars distribution.3. Fixed symmetry of I section alongside the slab in both directions4. Uniform effective depth as design proposed & fixed slab thickness, due to fixed steel cage height.5. Cold Joints covered: no need for extra steel for cold joints coverage; Steel cage legs work as shear links between concrete layers, in addition to Increased slab shear capacity6. Thanks to the well-designed SC structure, VF are wrapped firmly from the top and underneath by steel, guaranteed together with the sunken adequate bonding AT ALL TIMES.

20 - 45% Less slab 20 - 25% Less building structure weight Less building total height Up to 40% less columns Up to 20m span Cancellation of drop beams

Smoothness of stress distribution. No internal cracks. 100% controlled concrete quantit ies. Enhanced wave diffusion of sound impact.

Almost 18 EVOS sections in one square meter, which means the perfect bracing and bearing capacity, enhanced load transfer and reduced local punching.

B. Why One Factory Made Piece Steel Cage is Important ?

Why Voided Slab system ?

A. Why Void Formers ?

Engineering

Weight reduction is achieved by displacing concrete that would otherwise be under tension and therefore not contributing to the load bearing mechanism. The shape of create voids within the slab is dictated by the shape of the void former and it is the most important factor in determining the behavior of the voided slab. EVOS has undergone extensive development to obtain the optimal shape for efficient load-bearing ability and maximize load reduction and maximize stiffness factor.

The location of the voids is such that there is no interference with the compression areas of the slab. The stress-strain relationship therefore is not altered compared to a solid slab. Additionally, reinforcement covers are respected.

Stress/Strain Diagram

Cross Section in EVOS Slab

Concrete

Top Flexural SteelReinforcement

EVOS Module(SCU)

Design Concept

EVOS bi-axial voided slab can be designed and planned by any structural engineer. EVOS slab is dimensioned with the methods used for traditional solid slabs and compatible with any concrete design code. Just like any other two-way slab system, EVOS voided slab system is permitted to be analyzed and designed by any procedure satisfying equilibrium and geometric compatibility in accordance with any code. As well, the system is flexible during design, during construction & post construction slab cutting & coring. Finite element analysis can be used in any case and strongly recommended. EVOS voided slab system take into account the presence of solid and voided areas of the slab through the application of numerical adaptation factors to the parameters of dead load reduction, stiffness factor & shear force factor.

The system has, one factory made piece, positioning steel cage to ensure fixed symmetry of I section alongside the slab in both directions. In addition to keep uniform effective depth as designproposed & fixed slab thickness, due to fixed steel cage height. Steel cage legs work as shear linksbetween concrete layers, thus increasing the slab's shearing capacity. Moreover, the presence of the steel cage covers the cold joints so no need for extra steel for cold joints coverage.

Bottom Flexural SteelReinforcement

Site Application

Full Steel Cage Site Application

3D View of the assembly

Evos with full steel cage application, the following should be carefully considered:

3. Labors can walk-on top square of steel cage during top steel distribution.

Full Steel Cage, 1 single piece, factory-made, 2.5m length

3D View of the assembly

Mini Steel Cage Site Application

Mini Steel Cage, 1 single piece, factory-made, 2.5m length

Evos with mini steel cage application, the following should be carefully considered:

3. wooden boards are needed to walk-on during the distribution of the top reinforcement steel.

1. Cold joints coverage: vertical bars in the mini steel cage, cover the required steel for cold joints, no further shear links are needed.

4. I section: I section is maintained by securing Void former center-to-center distance in both directions by steel cage cavity spacing and by tying the bottom of steel cage to bottom of steel reinforcement at both ends of steel cage.

1. Cold joints coverage: vertical bars in the full steel cage, cover the required steel for cold joints, no further shear links are needed.

2. Bonding: provided bonding with full sc 15mm for the top steel reinforcement and 15mm for thebottom steel reinforcement (10mm sunken depth+5mm sc). In case more bonding is required diagonal steel rebar should be laid below and top void former, diameter subject to desired extra bonding.

I section: I section is maintained by securing Void former center-to-center distance in both directions by steel cage cavity spacing and by tying the bottom of steel cage to bottom of steel reinforcement at both ends of steel cage.

4.

2. Bonding: provided bonding with mini sc 10mm for the top steel reinforcement and 10mm for the bottom steel reinforcement (10mm sunken depth). In case more bonding is required diagonal steel rebar should be laid below and top void former, diameter subject to desired extra bonding.

Sections in Voided Slab system

Section before casting, full SC

Section before casting,mini SC

Section after casting, full SC

Section after casting, mini SC

Optimizing structural elements materials (slabs, columns, shear walls, footings andfoundations). Optimizing elevations materials (facade). Optimizing manpower cost.

Production of 1 m3 of concrete

Releases

210 kg of CO2 into the air

Is Green

Recycled materials

One 40 ft . container replaces the delivery of 20 concrete mixers to the job site.

More Economic 

Less CO2 emissions

City Friendly

Replaces

Hybrid Solutions

EVOS void formers can be used in slabs together with other slab systems at the sametime, such as with post tension, and/or precast planks, for maximized optimization andengineering benefits.

EVOS With Planks

EVOS With PT

At Site

2. Delivery to slab working area.

3. EVOS elements distribution at the Slab.

Assembly at the jobsite.1.

5. Ready Evos Slab before casting concrete.

6. Concrete Casting.

4. Tying EVOS Modules from both ends to the bottom steel mesh.

7. After the concrete casting, the slab is ready.

Eco Voided Slabs

Office 2006, JBC 1, Cluster G, JLT, Dubai, UAE

+971 4 4431150

info@cme-int.com www.cme-int.com