What is a concrete lattice

What is a concrete lattice?

A new slab system with precast concrete lattice-reinforced joists began to be developed in Germany in the mid-20th century, using brick blocks as filler, and a cement and sand topping. This new system was introduced in Brazil in the 1940s.

The ever-changing requirements of modern architecture, and the growing need for efficiency in civil engineering, drive the search for constructive systems that satisfy these aspects. They also need to ensure the structures’ requisites of load-bearing capacity, service performance, and durability.

Until a few years ago, the structure most widely used in the construction of building slabs was the solid reinforced concrete slab. This slab required extensive formwork and falsework and had a high self-weight, making it unsuitable for today’s requirements.

Pre-cast rib slabs are an alternative to traditional structural systems.

The precast slab is a reinforced concrete system that combines ease of construction with structural integrity on your build. Precast concrete is a construction material created by pouring concrete into a preshaped mold. The concrete is then left to cure. Once cured, the precast concrete product is delivered to the project.

This type of slab has been used extensively in civil engineering, especially in small and medium-sized buildings, as it consumes less concrete and wood. It doesn’t requires formwork and is safe and easy to build.

Precast concrete is often stronger than traditional systems. Not only are precast concrete products already reinforced with steel rebar, but the controlled curing process also ensures that the concrete will set correctly for maximized strength.

These slabs offer several advantages over other systems. Such advantages include reduced consumption of building materials, lower labour costs, simplicity and speed of installation, easy installation of service conduits, lower self-weight of the concrete structure, versatility in use, and economy.

At PJ Projects, our core product is our concrete rib and block slab, (sometimes called the pre-cast lattice rib and block system).

The lattice girder is essential to bond with your concrete topping. Reinforcing from 1Y10 up to 4Y16 to be cast accordingly, depending on lattice beam spans. PJ Projects can manufacture ribs of up to 13m long. The lattice girder forms a substantial key with the insitu topping. The reinforcing steel supports the rib’s unique shape to suit the loading. Our design has revolutionised the manufacturing of reinforced concrete slabs.

The Rib and Block Slab System comprises of Lattice Lintel Ribs, Hollow Core Blocks (see our post here on blocks), Reinforced Steel and Mesh. Our concrete rib and block slabs are the best products available today. They have a unique design and are perfect for self-installation.

This picture shows an example of our concrete rib and block slab (150mm x 50mm).

Concrete lattice beams are highly versatile, cost-effective, reinforcing alternatives to traditional suspended flooring systems.

A: Substantial key to bond with concrete topping
B: Ref. 1379/1479 Girder
C: 16m reinforced steel (rebar)

Benefits of The Concrete Rib and Block Slabs

The Pre-cast Concrete Rib and Block Slabs have several distinctive features that offer benefits over other rib and block and more conventional methods of construction.

These are:

1. Eliminates the Need for Conventional Decking Systems
Because the ribs and blocks form a complete deck into which the concrete is poured, the ribs merely require temporary support until the concrete has gained strength. Propping centres will vary from case to case, and will be specified by the Engineer.

2. Why reduce the conventional reinforcing?
The lattice provides a rigid, steel truss-like structure which, when cast into the concrete, enables the rib to withstand handling loads and support the weight of the hollow blocks construction loads. It also contributes towards the tensile reinforcement required in the completed slab, and provides an excellent shear key between the pre-cast rib and concrete.

3. Reduced Volume of Insitu Concrete
The hollow concrete block replaces a substantial volume of insitu concrete. This leads to a significant reduction in the dead load supported by the structure and subsequential cost savings made by the reduction in size of other elements, such as the beams, columns, and foundations.

4. Ease of Installation and Reduced Construction Time
Due to the simplicity of the system, it can be swiftly installed on site using less skilled labour than is needed for more conventional slab constructions. The use of ordinary pre-cast ribs means that the ribs are always straight, simplifying the installation of the beams and the placing of the blocks in between. As the lattice girder adds stiffness and handling facilities to the beam, the installation time of the system is reduced.

5. Design Benefits
The ribs are purpose-made under strictly controlled factory conditions, eliminating potential problems of “one size fits all” situations. The large variety of cast-in reinforcing combinations allows for economical design.

PJ Projects has been manufacturing pre-cast concrete rib and block first-floor slabs for more than 20 years.

We are big enough to provide all your pre-cast concrete requirements, but small enough to build a lasting relationship with you. We are well-known for our reliability and prompt service. PJ Projects is situated in Cullinan, just outside Pretoria. We supply pre-cast concrete rib and block first-floor slabs to building contractors, developers, and individual builders in the whole of Gauteng, Limpopo, and Mpumalanga provinces. We deliver within a 300km radius of our yard.

Our Value-added Services

We know the cost of construction – especially if contract deadlines are not met! PJ Projects is committed to making it easy for you to obtain concrete material, in time and on budget. We take pride in the quality of our products and offer value-added services for your convenience:

  • On request for a quotation, building plans are collected or emailed.
  • Should an engineer’s appointment letter be required, it can be arranged with our office.
  • An engineer’s site visit will take place after installation.
  • A certificate will be issued upon completion.

Contact us today to request a quotation or to ask us any questions you have. You can also call us directly on 012 736 9056 or 072 049 9560.

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