Where and how are beamless floors used, what types are there??

In contemporary architecture, beamless floors are an intriguing and becoming more and more common choice. In contrast to conventional flooring systems that depend on joists and beams, beamless floors distribute and support weight using different techniques. This method eliminates the need for obtrusive support beams and simplifies the structural design, providing new opportunities for the creation of large, open interior spaces.

These floors are utilized in a variety of constructions, including both residential and commercial buildings. Their adaptability enables more creative design solutions and bigger open spaces. They are particularly useful in constructions where it is essential to maximize floor area and minimize visible support components. Beamless floors are prized for their ability to enhance a room’s aesthetic appeal because they provide clear views and clean lines.

Beamless floor systems come in a variety of forms, each with special benefits and uses. Among the most popular are waffle slabs, which use a grid pattern to increase strength and use less material, and flat slab systems, which directly support loads with reinforced concrete. Knowing the various varieties can make it easier to choose the best solution for a project’s needs.

In conclusion, beamless floors are an example of a contemporary building method that prioritizes effectiveness and design freedom. Investigating beamless floor systems can improve the project’s appearance and provide useful advantages for both new construction and renovation projects.

What kind of plates are they called??

A construction design known as "resting overlap" uses monolithic slabs or a series of panels supported by load-bearing walls and columns. In addition to performing load-bearing and enclosing duties simultaneously, concrete slabs are known for their remarkable resistance to compression and fracture, as well as their capacity to tolerate high static and mechanical stresses.

Concrete has limitations when it comes to using it for lengthwise slab installations, though, because of its low tensile strength.

The highest resistance to bending loads is provided by pre-tension, which is found in beamless reinforced concrete floors. It also lessens the likelihood of cracks forming in the thickness of the concrete, increasing the project’s overall durability.

The requirements of the design dictate how the capitals are arranged. Where the floor slab connects to the load-bearing column, they must form the required rigidity. This ensures the stability of the framework and prevents it from being pushed along the capital’s contour.

A beamless floor with this type of reinforcement has a smaller design span and a more even distribution of moments throughout the slab’s width.

Three different types of capitals exist: type I for light loads, type II and III for medium and heavy loads. While beamless floors require more concrete to be installed than hollow or ribbed slabs, less steel reinforcement and embedded components are needed during their manufacture.

Where and when is it appropriate to install them??

Beamless floor slab installation is required for each construction site based on the technical and financial decisions the designers made for the particular operating conditions of the structure, such as for buildings with column grids of 6 × 6 m or larger if all industrial space must be used efficiently in the future.

Beamless floors have a "tendency" to cover large areas, but in actuality, they can be installed in structures of any construction volume.

They are frequently found on high-rise structures made of wall panels. Similar floors can be found in garages, warehouses, and industrial buildings.

These kinds of interfloor ceilings are rarely used in the construction of private homes, but they are frequently used in the building of large cottages, particularly when the walls are monolithic.

According to building regulations, installing beamless floors is advised:

• When constructing industrial buildings, where the type of production process requires smooth ceilings, in particular, in processing shops of food factories, meat and dairy enterprises and fish processing shops.
• On multi-storey residential and public buildings with a grid of columns 6x6m.
• At facilities to which increased SES requirements apply, for example, large industrial refrigerators.
• For buildings operating in aggressive environments.

What varieties are there??

These floors consist of a number of crucial structural components, including floor slabs supported by a network of columns, capitals, and framing beams. Half-capitals, also known as wall capitals, will be added to the end columns if the project did not call for the installation of strapping beams.

Beamless floors can be classified as prefabricated, monolithic, or universal prefabricated monolithic structures, depending on the technology used.

Prefabricated

Forms for prefabricated beamless floors consist of capitals, columns, and slabs. The former are separated into span and intercolumn slabs. To support span slabs, intercolumn ones are mounted on capitals.

The most economical type of beamless construction is this one. It is utilized when there is a maximum span of six meters between columns or other comparable load-bearing supports, and the load on such floors cannot exceed 10 kN per square meter.

Similar circumstances apply to monolithic or stone structures with prefabricated floor slabs. They are constructed from hollow-core structures or lightweight concrete panels.

Multi-hollow ones differ in that they are relatively light despite having stiffness due to internal holes arranged along the length that create stiffening ribs.

The size of the span and the load that the slabs must support determine the slabs’ dimensions. Prefabricated floors typically have the following industrial dimensions: height of 220 mm, width of 1.5 m, and maximum length of 7.0 m. The permissible range for the thickness difference between the span and intercolumn slabs is 2 to 4 cm. The slabs must be of equal thickness.

Prefabricated slabs are manufactured on serial equipment because their dimensions have to meet industrial production requirements. These products have a minimum length of three meters. Prefabricated elements typically have a width of at least 2.4 meters. There’s a chance that some slabs are smaller in size. The capitals’ maximum height is limited to 600 mm.

It is advisable to install columns in buildings that have multi-story sections, or several storey spans in height. A layer of working mortar made of cement is used to mount the slabs. If load-bearing walls are at least 250 mm thick, the 200 mm minimum support needed for a beamless slab will be satisfied. Concrete mortar is used to seal the tile joints after the slabs are laid.

Benefits of prefabricated beamless flooring include:

• high strength, ability to hold loads over 200 kg/m2;
• good manufacturing characteristics in terms of strength;
• high fire resistance;
• high water resistance;
• high biological resistance.

The remarkable weight is attributed by developers to the drawbacks of these floor changes. The high overall cost of construction is a result of the need to install them using specialized lifting equipment.

Prefabricated monolithic

This is a combination option for installing beamless floors: on specific structures, hollow blocks with a 600 mm pitch are first installed. The supporting framework serves as long-term formwork. A robust monolithic connection is produced by pouring concrete over steel mesh reinforcement.

The lightweight concrete blocks weigh no more than 20 kg per square meter for this design, 14 kg for expanded clay concrete blocks, and 5 kg for polystyrene concrete blocks. Using heavy lifting equipment is not necessary for this option.

Prefabricated monolithic beamless flooring benefits include:

• no lifting equipment is required during the installation process;
• high strength with a relatively low weight load;
• simple installation;
• high heat, water, noise and fire protection;
• easy to assemble ceiling of any configuration.

A few drawbacks for developers are the comparatively high cost of the original blocks and additional materials, as well as the higher labor intensity of installation because of the small-sized blocks.

Monolithic

Modern high-rise building has led to a widespread increase in the popularity of monolithic beamless floors. There are currently two basic techniques for prestressing these load-bearing structures:

• on supports, which are load-bearing walls and column supports;
• onto concrete using the method of tensioning reinforcement, after completion of laying and the concrete acquiring design strength.

Because prestressing reinforced concrete structures reduces the beamless floor’s design cross-section, it is possible to achieve significant cost savings with any option.

Formwork, concrete mortar, and reinforcement are used to directly create structures on the construction site. Builders particularly like these slabs because the technology makes it possible to design any kind of floor.

Load-bearing monolithic walls support a solid 12-centimeter-thick slab of reinforced concrete known as monolithic beamless flooring. One square meter of the slab weighs about 500 kg, making the structure relatively heavy.

There are multiple stages to the installation process:

1. First, load-bearing iron beams are placed on the prepared support area on the walls.
2. Formwork made of boards is fixed to them.
3. Only after this, they begin to install the reinforcement frame.
4. Formwork is poured simultaneously over the entire area. Concrete solution hardens in 28 days.

Benefits of monolithic floors without beams:

• obtaining a smooth outer surface of the floor that does not require additional sealing of the seams;
• a large selection of forms makes it possible to use the method for a variety of architectural projects;
• no lifting equipment is required during installation;
• high strength with a relatively low weight load;
• easy installation;
• high water, bio- and fire protection.

The requirement for formwork to be arranged throughout the entire area is viewed negatively by developers. While it is occasionally permitted to fill in gaps by relocating the formwork once the concrete has hardened.

With and without capitals

Capital serves as a safeguard in a beamless construction system. They are put in place on supports that lessen above-column moment and deflection while also shielding the slab from punching.

By increasing the floor’s fracture strength and ensuring the design rigidity of the slabs’ interfaces with the load-bearing supports in the building’s frame system, they protect the slabs from pushing through where the columns rest.

The calculations for every individual construction project are used to determine the dimensions of the capitals for each of the three. There are currently three types of capitals used in construction: straight, with a cap plate, and with a break.

For light loads, use option number one; for large loads, use options number two and three. A fractured capital is regarded as the most beautiful architectural feature and is capable of supporting the heaviest loads.

You must keep in mind that practical and design characteristics are not the same for capitals when doing calculations. Its computed width is the same as the section’s diameter at the slab’s boundary with the plane. The primary tensile moments of the structure are located along the external contour of the walls around the whole perimeter to determine the characteristics of capitals.

Citation. The ratio of capital size to span, which is 0.33 when average design stresses are taken into account, is thought to be the best actual indicator, while the design indicator is equal to 0.2.

As is customary, capital reinforcement is not carried out because the cross-sectional area of the materials ensures that neither compressive nor tensile loads are generated that exceed SNiP standards.

Only when improving the connection between the column and the floor or when specific operating conditions are needed for the project can reinforcement be justified. In this instance, standard 10 mm reinforcement is used to reinforce capitals without kinks, and it is positioned in the center of each side as well as the corners.

Capitalless columns can be installed with beamless floor slabs. With support columns that have a constant cross-section and equal-thickness reinforced concrete slabs, this is the most straightforward design option.

In addition to making concrete pouring and the laying of reinforcement cages much easier in practice, this design greatly streamlines the implementation of formwork operations.

This can be explained by the fact that column structures without capitals have a constant height cross-section, which allows them to precisely match the walls built in between the columns. In actuality, this strategy has shown to be effective for both residential and office buildings.

These systems stand out for having a low structural height and a smooth, flat ceiling, which let you efficiently arrange the furniture and equipment inside. In this instance, the false ceiling-covered ceiling portion is where utility networks are installed.

The task of limiting deflections needs to be completed in capitalless floors. Because of the resulting thin slabs, they are important in capitalless structures. In this instance, the system’s elastic deflection value at least doubles with an increase in creep strain.

When capitalless buildings were being constructed in the late 1950s, this issue was particularly prevalent in practice, as walls and windows would occasionally break. Thanks to modern building techniques and sophisticated computer calculations, this issue has been totally resolved.

Caisson

It goes without saying that this beamless floor installation technique is the most widely used in contemporary building. In EU countries, it is now widely used in the construction of administrative buildings where suspended ceilings are planned. The presence of ribs that are perpendicular to one another distinguishes cofferded slabs from other ribbed slab structures.

The ribs are reinforced to give such a structure the maximum rigidity and strength. Today’s caisson technology stands out for its ability to produce floors with the lowest production costs per square meter while still meeting standard indicators for strength and other requirements for reinforced concrete floors.

Plastic formwork is used to create a monolithic coffered slab. To start, the slabs are positioned slightly apart from one another to form unique spaces into which concrete mortar can be poured.

The cells are covered with a layer of fixing mortar after the reinforcing mesh is put in place. Currently, construction sites use coffered slabs that range in thickness from 250 to 450 mm. A monolithic concrete floor is created at the locations where the slabs connect to the capital and column.

The main characteristic that sets these systems apart is the concentration of concrete in compression areas, which is made possible by a perpendicular stiffener system that was developed, taking the concrete out of the tension zone. This results in a system with the maximum rigidity while also allowing for significant concrete mortar savings.

Crucial! Steel lathing and vertically positioned racks make up a special formwork that is used to properly reinforce the coffered floor slab.

Because concrete doesn’t stick to plastic, they are installed with consideration for the caisson formers’ dimensions, which will be used when they are positioned on top of the sheathing. As a result, following the concrete solution’s final hardening, the forms are simple to disassemble.

Regulatory Requirements

Beamless floors are intricate constructions, the dependability and longevity of which dictate the overall project’s performance parameters. In the area of urban planning, they are governed by numerous regulatory and subregulatory acts of the government:

• GOST 2590-2006;
• GOST 27751-2014;
• GOST 380-2005;
• GOST 535-2005;
• GOST 6727-80;
• GOST 7473-2010;
• GOST 7566-94;
• GOST 8267-93;
• GOST 8731-74.

Their actions are first intended to guarantee the safety standards for different design impacts during building construction and operation:

Consequently, any chance of destruction must be eliminated when building structures in order to protect people’s lives and health, property, and the environment:

• GOST 13015-2012;
• GOST 14098-2014;
• GOST 17624-2012;
• 22690-2015.

Acts of regulation Beamless floors are subject to specific requirements under SP Nos. 2.13330, 14.13330, 20.13330, 22.13330, 28.13330, and 131.13330 regarding maximum loads, deflections, deformations, fire resistance, moisture resistance, and frost resistance. Every indicator is adjusted based on the development area’s climate and seismic characteristics.

Characteristics and parameters

Beamless flooring needs to:

• carry the required design loads without damage;
• have rated steel, not bend under the load of its own weight and located equipment;
• possess the calculated heat, sound, moisture and biological protection, meet all SES and fire safety requirements;
• have initial characteristics to prevent the formation and excessive opening of cracks and other defects that disrupt the normal operation of the floors;
• have a service life no lower than that established for the wall structures of the building.

It will be necessary to use source materials whose characteristics will comply with SNiP standards in addition to correctly designing and installing the structure in order for all regulatory document requirements to be satisfied and the resulting reinforced concrete products to comply with GOST 27751.

The primary standardized and regulated attributes of concrete production quality are taken into consideration.

1. The optimal grade of concrete is M300-M400, and if operating conditions require it to withstand large flows of water, then grade M450-M500.
2. Compressive strength class: B2-B5.
3. The standard axial tensile strength of concrete must correspond to – 0.95 MPa.
4. Frost resistance grade F is responsible for the safe number of freezing/thawing cycles, must be no less than that of wall structures and can be in the range F=100-300.
5. Waterproof grade W, set according to the highest water pressure that can withstand concrete 15 cm thick. For example, W2 does not allow water to pass through when a slot 20 m high presses on it.V.st. (2 bar), and W12 can accordingly withstand 120 m.V.st. For the production of beamless slabs, waterproof grades from W2 to W12 can be used.
6. The mobility of concrete “P” is not lower than class 4 to guarantee high-quality filling of the reinforced structure.
7. The optimal grade for medium density D300-D600 corresponds to the compressive strength class B2-B5.

Installation process

Prior to beginning the construction of a monolithic beamless concrete floor, set up the necessary instruments, supplies, and hardware.

Technology used in manufacturing:

1. Start assembling the formwork. You will need a 20-30mm board for the side walls, a 30-40mm board for the bottom and 20mm waterproof plywood.
2. To place the formwork, use transverse beams and supports, with a distance between them of 1-1.2 m.
3. After the formwork is placed strictly horizontally, install the side walls and cover the bottom with film to prevent the solution from flowing out through the cracks and to form a smooth and even surface of the slab.
4. Reinforcement is carried out strictly according to calculation, as a rule, with wire D 10-14 mm, depending on the calculation results.
5. Knit a mesh of reinforcement with a pitch of 200 mm using soft annealed wire.
6. Reinforcement is used in whole pieces, if the length is not enough, overlap with a distance of at least 40D.
7. The joints of the connections should be staggered.
8. The mesh is reinforced at the edges with U-shaped elements, the lower zone of the mesh is reinforced above the openings, and the upper one – above the installation of load-bearing walls. In addition, reinforced reinforcement is performed in the places where the columns rest.
9. For pouring, M400 concrete is used in the composition: crushed stone-sand-concrete, as 4:2:1.
10. The concrete solution is poured alternating opposite corners, first in one, then in the opposite direction.
11. A deep vibrator is used to remove air voids.
12. The pouring process is continuous, after completion, the upper surface is leveled with devices similar to mops.
13. The formwork is removed approximately 3 weeks after the end of pouring, when the floor has gained at least 80% of its strength. Even if the formwork needs to be removed earlier, the load-bearing supports are left until the complete process of forming the strength of the monolith for at least 28 days.

Crucial! Throughout the first week, water is periodically poured onto the monolithic structure’s surface to keep it from drying out and cracking. It is advised to cover it with damp burlap or film to retain moisture on especially hot days.

Defects, causes and their elimination

When large-scale destruction occurs during the production of beamless floor slabs, defects may become apparent right away or gradually become visible over time. The client must set up ongoing quality control procedures for construction and installation work to stop this from occurring at the job site.

Inadequate work preparation, flimsy scaffolding, delays in the embedding of joints cause fractures that endanger the integrity of the slabs, and the concrete is destroyed where the capitals meet the slabs, causing the concrete to sag in the slab body.

The primary infractions in the beamless floor production process are:

• violation of reinforcement rules;
• violation of the reinforcement scheme and the use of thin rods;
• erroneous definition of assembly joints, concreting sections;
• concreting during the cold period of time, without organizing electric heating;
• violation of the design technology for welding embedded elements;
• shift of reinforcement meshes and embedded elements allowed during installation leads to peeling of the monolithic part of the capitals;
• incorrectly applied concrete grade during monolithic works.

Regretfully, not all installation flaws are immediately apparent; in fact, a lot of them are only discovered during operation or geodetic surveys. In this instance, beam-free slabs gradually deviate from the plan, and collapses happen all at once.

Pros and cons of use

Such monolithic structures have a service life of several hundred years or more. Buildings with such floors can serve multiple generations of owners because during the first 50 years, the monolith only gets stronger. The primary benefit of employing beamless concrete floors in buildings is this indication.

Experts believe that using such floor plans has the following additional benefits:

1. Possibility of installing reliable floors in rooms of different shapes and sizes.
2. High fire resistance of the structure; all beamless ceilings are non-combustible materials and can serve as reliable barriers for the spread of open flames.
3. High moisture resistance.
4. High strength and durability.
5. The absence of seams and joints on the surface of the floors, which simplifies finishing work.
6. The low specific gravity of the floor is caused by the small thickness of the slabs, which does not reduce the strength characteristics of the building, but at the same time significantly reduces the load on the base and load-bearing walls of the building.

The installation of such slabs can be done with specific wall structures made of reinforced concrete or monolith; installation is done at temperatures above + 5C; the size of the spans can only be 5 × 6 m at a standard load of 5 kN/m 2. These structures have several drawbacks, including a rather complex technological process of construction and installation work.

Furthermore, she acknowledges that the design process for these kinds of structures is extremely responsible and labor-intensive.

The use of beamless floors, commonly referred to as flat slabs, in contemporary construction is growing due to their streamlined appearance and effective load distribution. These floors use a thicker steel-reinforced slab in place of beams, giving architects more creative freedom and allowing for higher ceilings. They are especially well-liked in parking garages, commercial spaces, and high-rise buildings because they can sustain large loads and offer a continuous, smooth surface. Depending on the particular needs of the project, beamless floor types such as waffle slabs, ribbed slabs, and flat plates each have their own advantages.

Average prices

The cost of installing beamless floors can vary significantly depending on the volume of construction, the height of the work, and the chosen floor model. Prefabricated monolithic systems are the most easily obtainable and prefabricated systems for the private sector; capital-intensive monolithic systems are the most costly.

Average costs for beamless floor installation and materials:

No	Name of work/product	Dimension	Cost per unit, rub.
1.	Capital KP 1-1-1, 2980x2980x600 mm, 1.8 m 3	PC.	36500
2.	Monolithic floor with reinforcement and formwork	m 3	7300
3.	Installation of a monolithic ceiling using a profiled sheet	m 3	5600
4.	Installation of prefabricated monolithic floors:
4.1	Metallized beam "Homeowner" from 1.0 to 4.0 m	1m.P.	730
4.2	YTONG steel beam up to 9m	1m.P.	1300
4.3	Expanded clay concrete block liner 200x520x200	1 PC.	90
4.4.	Assembly work	m 3	4200

Usage	Types
Beamless floors are often used in modern buildings to create open spaces without columns or beams. They are popular in office buildings, commercial spaces, and residential constructions.	The main types of beamless floors include flat slab floors, waffle slab floors, and ribbed slab floors. Each type has its own benefits and is chosen based on the specific needs of the building design.

Beamless floors are a cutting-edge approach to modern building that have many advantages for a range of building uses. Their efficiency and adaptability allow them to be used in both large commercial buildings and residential dwellings. These floors provide a sleek and streamlined design that maximizes space and offers a modern aesthetic by doing away with the need for conventional beams.

Beamless floor types come in a variety of forms, each suited to a particular set of building requirements. Flat slab systems are widely used in low-rise and residential buildings due to their simplicity and ease of installation. Waffle slabs are frequently used in larger buildings where strength and durability are essential because of their grid-like structure, which offers excellent load distribution. Finally, ribbed slabs offer a balance of strength and simplicity by combining the advantages of both.

The exact needs of the project, such as load-bearing requirements, architectural design, and budget, will determine which beamless floor type is best. Whichever variety you choose, these floors have a lot to offer, including shorter construction times, less material consumption, and more interior design flexibility. Beamless floors are expected to become even more common as building technology develops, completely changing how we construct residential and commercial buildings.

Video on the topic

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