What is a concrete grillage: its varieties, creation technology

Upon delving into the realm of engineering and construction, you may encounter the phrase "concrete grillage." Although it sounds technical, this idea is very important to infrastructure and building design. Concrete grillages are essentially a kind of foundation system that give structures stability and support. Consider it as a robust subsurface framework that is intended to disperse weight uniformly and avert settlement or movement.

Concrete grillages come in a variety of varieties, each suitable for a different set of circumstances and demands. Single and double grillages are among the most popular varieties. Usually consisting of a single layer of beams, a single grillage is utilized for situations with lower loads or less demanding circumstances. A double grillage, on the other hand, has two layers of beams and provides additional strength and stability for heavier structures or more difficult situations.

A concrete grillage is made up of several essential steps. Engineers first create the grillage based on the project’s unique specifications. After that, the beams are arranged in a grid pattern and concrete is poured over them, allowing the concrete to cure and set. Because of its meticulous construction, the grillage is guaranteed to support the anticipated loads and serve as a strong base for any structures that are built on top.

Gaining an appreciation for concrete grillages in construction can be achieved by knowing how they operate. Although they may not be the most visually appealing component of a structure, they are essential to maintaining its stability and security. Understanding concrete grillages can help you better understand how structures are supported from the ground up, whether you’re building a house or a high-rise.

Aspect Description
What is a Concrete Grillage? A concrete grillage is a type of foundation used to distribute loads evenly. It consists of horizontal and vertical concrete beams or slabs that spread the weight of a structure over a larger area.
Types of Concrete Grillage 1. **Single Grillage**: Made of one layer of beams. Simple and used for lighter loads.
2. **Double Grillage**: Consists of two layers of beams crossing each other. Used for heavier loads and better distribution.
3. **Slab-and-Beam Grillage**: Uses a combination of concrete slabs and beams. Provides strong support and is used in various applications.
Creation Technology The process starts with designing the grillage to suit the load and soil conditions. Concrete beams are cast, often using molds. Once set, they are arranged in the required pattern and connected. Reinforcement bars are included to strengthen the structure. Finally, the grillage is tested for stability before being covered with additional layers if needed.

Before starting the grillage device

You must plan and prepare everything before putting in screw piles with a concrete grillage. Utilizing a tape measure and computations, marking is done. The necessary number of steel rods for reinforcement and the shields needed to install formwork are ready in advance. A grinder (for cutting reinforcement), additional supplies, and work tools might be required.

It is preferable to arrange the formwork shields and fasteners according to brands and sizes to facilitate work. The remaining tools and supplies are the same as those required for any reinforced concrete project. Several tasks must be completed in order to install screw piles with a concrete grillage (per the standard).

  • Draw up foundation acceptance certificates according to the diagram.
  • Determine storage locations, movement paths of mechanisms, enlargement of reinforcement meshes, formwork, prepare all tools and equipment for work.
  • Sand and concrete preparation for the grillage must be completed.
  • Temporary lighting of the facility, connection of devices.
  • Mark on the surface the installation locations of the formwork for pouring.

Types and purpose of grillages

A grillage’s design may vary based on its type, function, and purpose.

– A frame constructed of metal beams welded to the tops of screw piles is known as the grillage.

It is noteworthy to discuss pile bushings separately; these grillages are distinguished by the use of multiple piles that are secured at the top. Together, they function as a sort of "bundle," submerged in the earth next to one another to efficiently accept and distribute point loads or loads from columns. Usually, industrial and energy construction use this kind of strip grillage structure. A concrete grillage is typically made by hand in private construction.

Strip foundations with grillages

This kind of foundation serves as the structure’s dependable and long-lasting support. Two methods exist for implementing a structure with strip grillage: one involves using the technology above ground, and the other involves constructing a lattice structure that is intended to support a specific portion of the load.

Strip foundations with grillage are typically placed in complex terrain areas, on slopes. This type of design makes the foundation dependable without requiring the use of specialized equipment or intricate design work, which makes it perfect for buildings made of lightweight materials.

A 30-centimeter layer of sand must be filled under the concrete frame in order to implement this type of pile-screw structure. Additionally, the supports and lattice (made of roofing felt, polyethylene film, or asbestos-cement pipes) must be waterproofed. Carefully calculating the pitch and number of piles, the thickness of the grillage, and other parameters is also necessary.

For a fence

In this instance, complete fence protection is the main objective, which a traditional flat fence is unable to achieve. The functions, materials, and design of a grillage for a fence are nearly the same as those of a structure of a similar kind for a house foundation.

For a pile foundation

A columnar foundation with a grillage is arranged for certain building structures, guaranteeing the required parameters of rigidity and weight of the frame. The supporting columns are strapped with a monolithic wooden, metal, or reinforced concrete belt to keep them from collapsing.

Plans for pile foundations for buildings:

  • Pillars resting on a crushed stone embankment without deepening into the soil. The foundation of the house is rigid, it is possible to exclude subsidence.
  • Deepening columns with a suspended belt into the ground is the most common scheme of pile foundations.
  • Without a grillage – relevant for the construction of small buildings.

Types by placement

There are various design options for the grillage depending on where it is placed in relation to ground level. The foundation requirements, the land’s features, and the planned building are taken into consideration when selecting a particular project.

High

25 centimeters or more above the soil’s surface is considered a high grillage. This option makes it feasible to achieve increased floor ventilation while removing the possibility of mold and moisture buildup. By raising the grillage above the ground, you can timely make foundation repairs and conduct routine foundation inspections.

You can store tools, garden tools, and other items in the subterranean area. This kind of grillage’s primary drawback is its incapacity to build a fully functional basement.

Elevated

The most common type of raised grillage in construction is ground level. The base of the tape is a sand and gravel cushion that is ten to fifteen centimeters thick. To construct it, the necessary amount of soil is taken out and replaced with gravel. This is one method of setting up an anti-heaving cushion to stop the soil from rising during a frost.

By lowering the soil’s moisture content, a gravel cushion keeps water from building up beneath the foundation. The primary benefit of this kind of grillage is the notable enhancement of heat-saving properties due to the lack of a blown space between the soil and the ceiling.

Recessed

This grillage is situated below ground, in a designated trench where formwork is mounted and concrete mortar is poured after piles are installed. A room built on such a foundation is strong, dependable, and has exceptional heat-saving qualities.

A concrete grillage is a structural framework that is frequently used in civil engineering and construction. It is composed of steel and concrete and offers a strong foundation for supporting large loads. This article discusses the various forms of concrete grillages, ranging in complexity from straightforward to intricate designs, and details the methodical procedure for making them. We hope to simplify the understanding of concrete grillages and their significance for sturdy and stable structures by dissecting the technology and techniques involved.

Pile-grillage foundations

Numerous factors influence the technology selection for building a pile-grillage foundation. Considering the design elements, the concrete grade for the grillage, the materials, and the technologies employed all play a part.

Technology of grillage with bored piles

When building on slopes, uneven ground, or unstable soils, a foundation with a grillage on bored piles is required. This is a wise decision when building medium-sized and small-sized structures. Grillage-supported bored pile foundations are significantly less expensive and have a higher bearing capacity than strip and monolithic foundations.

Up to 1,500 kilograms can be loaded onto bored piles. Every pile needs a waterproofing layer, which is constructed from two layers of roofing felt or roofing felt and fixed in a layer of non-freezing soil. Concrete is shielded from deformation and the pressure of soil on the supports is lessened by waterproofing.

The following are the key benefits of a bored pile foundation:

  • Installation in any type of soil
  • Preservation of the surrounding landscape
  • Absence of impact of dynamic forces on nearby buildings
  • Location below the freezing level of the soil
  • The ability to install under buildings made of brick, wood, frame type
  • Low cost
  • Installation speed

The pillars are put in place, their apexes are leveled, and they are connected by a single belt. The structure’s weight can be distributed uniformly throughout the base thanks to this grillage. The space between the soil and the floor that results from a grillage using bored piles is a drawback because it necessitates the insulation of the foundation, which adds to the cost, time, and effort.

Grillage on screw piles

This kind of foundation has the benefit of not requiring excavation work to be installed. Buildings on heaving or clayey soils can be constructed with a grillage on screw piles. Their heads are leveled off and the lattice belt is put in place after the supports are installed.

Since these supports are typically designed for lightweight buildings, installing a monolithic concrete or reinforced concrete base for screw piles is essentially never done. The grillage’s metal structure is typically composed of metal angles or channels. Metal platforms that allow for the adjustment of the axial displacement of the supports are welded to the heads of the screw piles prior to the installation of the grillage. After that, a channel or angle is used to tie each pile together, forming a sturdy and dependable structure.

Creating a pile-grillage foundation with your own hands

You can certainly construct a pile-grillage foundation by hand. A grillage on a columnar foundation is selected for the construction of small buildings (gazebos, summer cottages), while the pile option is appropriate for structures that will be occupied permanently. The best times to complete the work are in the late spring, early summer, or early fall. Prior to beginning the next phases of the work, the site must be cleared of any vegetation and debris.

It is necessary to order concrete with a strength class of B17.5–22.55 or purchase ingredients to be mixed with concrete in a concrete mixer in advance. Under the future strapping, add gravel or small crushed stone if needed.

Formwork

Ten centimeters above the height of the strip grillage is where the forming is installed. The wooden boards or planks used to construct formwork must be strong enough to support the weight of the concrete without breaking or dispersing.

How is reinforcement performed

Rebuilding a precast monolithic grillage is necessary. The project will determine the depth of the steel rods used for reinforcement, which have a cross-section of 12–18 millimeters. The mesh is laid uniformly with a step of 15–30 centimeters. The tape’s base has tie-downs installed all the way around.

Prior to installation, the wire is cut, the frame is mounted in the formwork, and it is then securely fastened to the pile reinforcement. The upper portion of the piles that protrude above the soil’s surface are drilled with holes, embedded components are inserted through them, and longitudinal reinforcing whips are fastened to them. The upper whips are tied together with steel rods that are inserted into the piles. A layer of two to three rods of reinforcement is placed inside the piles.

Concrete

Equal horizontal layers of concrete are poured, with a thickness of ten to fifteen centimeters. Before pouring the next layer, each one must first be successively tamped with a vibrating tool.

Once the formwork has been filled, the pillars should be inside the concrete monolith, just like the lower rods of the reinforcement cage. The upper edge of the pile should not be level with the concrete base. Before pouring, metal pipes are first inserted into the piles and shaken to fill the interior volume. Filling the void left by the edges of the formwork panels is the final step.

Pouring the grillage can be done with concrete of grade M300 or M350.

Grillage: weather and temperature-humidity conditions

Installing the grillage occurs during hot, calm weather—ideally without any precipitation. Additionally, the surface shouldn’t be exposed to direct sunlight. When the air temperature is below zero, the concrete needs to lose as little heat as possible during the preparation and laying processes. In order to prevent freezing, the ground must first be warmed to a positive temperature before beginning any work on heaving soils.

Dismantling the formwork

Following the concrete pour, the formwork is taken apart, with the spacers and fasteners removed before the boards are removed. If the formwork panels are unable to effortlessly separate from the hardened monolith, the solution has not yet reached the necessary strength and hardness.

Drying and care

The monolith needs to be properly cared for when the concrete grillage is poured. The building is consistently shielded from the sun, wind, and precipitation. If the air temperature rises above +22C, the polyethylene film covering the surface is periodically moistened with water.

Waterproofing

Waterproofing the concrete grillage is essential, particularly when building recessed pile-grillage foundations. It’s also a good idea to keep damp areas away from raised grillages.

The kind of soil, the level of groundwater, the type of grillage, one’s ability to pay, and other considerations all influence the waterproofing method and material selection.

Gaining an understanding of concrete grillages provides a strong basis for a variety of structures and opens up a world of construction possibilities. These grillages are necessary for both residential and commercial projects because they distribute loads and provide stability. The success of your project can be greatly impacted by your understanding of the various types of concrete grillages and their applications, whether you’re designing a new home’s foundation or strengthening a commercial building.

There is flexibility in meeting various structural requirements thanks to the variety of concrete grillages available, ranging from straightforward beam grillages to intricate multi-layered designs. From load distribution capabilities to cost efficiency, each type has advantages of its own. The scale of the project, the amount of load required, and the budget all play a role in selecting the appropriate type.

Concrete grillage creation is now more reliable and efficient thanks to advancements in technology. More durability and improved quality control are guaranteed by modern methods. Comprehending the process can aid in making well-informed decisions and achieving optimal outcomes for your construction requirements, regardless of whether you choose to use prefabricated components or cast on-site.

Concrete grillages are essentially a fundamental component of contemporary architecture. Understanding their varieties, applications, and production processes gives you important new perspective on a cornerstone of building design. This information guarantees that your construction projects are built on a stable and dependable foundation in addition to aiding in planning and execution.

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Marina Petrova

Candidate of Technical Sciences and teacher of the Faculty of Construction. In my articles, I talk about the latest scientific discoveries and innovations in the field of cement and concrete technologies.

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