Because of their efficiency and versatility, hollow floor slabs, also referred to as multi-hollow slabs, are a common choice in construction. The hollow cores of these slabs provide weight reduction without sacrificing strength. Their distinct design improves their insulating qualities while also making them simpler to handle and install.
Hollow floor slabs, which are frequently utilized in commercial, industrial, and residential buildings, offer a dependable way to create expansive, open areas. They are perfect for floors and roofs because they can span large distances without the need for additional support structures. Faster construction times and lower construction costs are results of this structural efficiency.
Hollow floor slabs come in a variety of sizes and types, so they can be customized to fit the needs of a particular project. There is a slab type that works well for both high-rise buildings and industrial warehouses, depending on the needs of the latter. To choose the best slab for your construction needs, it is essential to comprehend the options and technical features.
| Application | Description |
| Residential Buildings | Used for floors in houses and apartments due to their strength and insulation properties. |
| Commercial Buildings | Common in offices and retail spaces, providing a solid, durable floor structure. |
| Industrial Buildings | Ideal for warehouses and factories, offering strong support for heavy machinery and equipment. |
| Parking Garages | Used in multi-level parking structures for their ability to support vehicle weight and resist weather conditions. |
| Bridges | Employed in bridge construction due to their load-bearing capacity and long-span capabilities. |
| Schools and Hospitals | Chosen for their fire resistance and acoustic insulation, making them safe and quiet. |
Because of their excellent thermal and sound insulation qualities, strength, and low weight, hollow (multi-hollow) floor slabs are frequently used in construction. They are frequently seen in residential, commercial, and industrial buildings, supporting the roofs and floors while lightening the structure’s overall weight. These slabs are made to meet precise technical requirements and are available in a range of sizes and types to accommodate different architectural requirements. Their durability and stability in a variety of environments is guaranteed.
- Application areas
- Design features
- How they are made
- Advantages and weaknesses
- Technical characteristics
- Load that hollow-core panels can withstand
- Reinforcement
- Dimensions
- Marking
- Video on the topic
- Openings and openings in hollow-core slabs
- Sizes of reinforced concrete slabs
- Floor slabs: sizes, what they are for their intended purpose, stages of slab installation
Application areas
In brick, concrete, and block buildings, hollow slabs are frequently used in the arrangement of floors at the joints between floors.
Both private residences and multi-story buildings have been built using this design. Options for reinforced concrete can serve as frames that support loads. Multi-hollow slabs are used in the construction of industrial complexes.
Mains for heating are another use for the slabs. They let you install pipes and shield them from harm by hiding them beneath a layer of dirt.
- Hollow.
- Ribbed.
- Solid.
- Monolithic.
- Solid additional.
- Lightweight.
Products made of solid materials reliably guard against deterioration and deflection. Having a minimum thickness of 160 mm, they exhibit excellent thermal insulation qualities and do not back down from forceful impacts.
In order to construct buildings out of wall blocks, concrete, and bricks, hollow varieties are created and placed in between floors. The building’s insulation against heat and sound is enhanced because it is not a monolith.
Products with ribs are used to arrange roofs on industrial buildings. They are typically installed in:
- Warehouses.
- Industrial garages.
- Hangars.
Given that reinforced concrete is used during the production process, monolithic solutions have the advantage of strength. They can also be used to construct multi-story buildings and do not fear large loads.
High-density concrete, which determines high strength properties and resistance to intensive use, is the foundation for the creation of solid slabs.
The lightweight variant is hollow inside and has a low weight. It can be applied when building a structure whose foundation is not strong enough. The foundation is under less load thanks to the slab.
Design features
Different floor slabs (FS) with varying design features and characteristics are available in the construction market. All types, however, are predicated on the following elements:
- Concrete. Created on the basis of Portland cement grade M300 or higher. A high-quality mixture helps to increase the strength and reliability of the structure.
- Steel reinforcement of class A3 or A4, which is installed in a stressed or free position. The use of reinforced elements ensures high resistance to loads.
The following structural characteristics define hollow-core floor slabs:
- Correct geometry. The product is given the shape of a parallelepiped with smooth edges.
- The presence of through cavities in the end zone. Their task is to improve the properties of sound and heat insulation.
- Specific configuration of the cross-section of the cavities. They are made round or oval.
- Dimensions. The length, width and diameter of the holes are determined by the features and type of the slab.
- Number of holes. It is selected taking into account the regulated standards and requirements.
The following benefits are made possible by the longitudinal channels’ enhancement of the slabs’ performance characteristics:
- Simplification of the installation of utility lines.
- Increasing the thermal insulation of the interfloor ceiling.
- Protection of the building from outside noise.
The lighter weight and lack of additional load on the base are two ways that hollow-core panels differ from solid alternatives. They also promise good thermal protection and soundproofing qualities.
How they are made
Slabs with hollow cores are composed of various varieties and blends of concrete. Including:
- Silicate.
- Light.
- Heavy.
Several technologies and techniques are employed when creating hollow structures based on the types of concrete mix mentioned above:
- Without formwork. Automated equipment with support for vibration compaction is used to manufacture such products. The workpiece gradually moves along the line and is processed using automation, which gives it the correct geometry and overall dimensions of hollow-core floor slabs. In order to increase the density, the structure is equipped with reinforcement ropes.
- With formwork. The concrete mix is placed in standard metal formwork with metal rods and reinforcement. When hollow-core slabs undergo the tamping procedure, they are processed in hydrothermal chambers. Upon completion of the process of steaming, the products are taken out of the formwork and left to solidify.
Given that it doesn’t require sophisticated tools or technology, the second approach is thought to be more common. It is typically utilized in industrial settings where hollow-core slabs made of reinforced concrete are manufactured. The strength properties are increased when reinforced elements are present.
Advantages and weaknesses
The advantages of the PC floor slab are as follows:
- Reduced weight. Unlike a solid panel, a hollow structure demonstrates increased strength properties with the same dimensions. At the same time, the product does not exert large loads on the frame and base.
- Affordable cost. A hollow-core floor slab is cheaper than a solid one, since its production requires less raw material. This reduces the cost of resources for the production process.
- Improved thermal protection and absorption of external noise. Such properties are associated with the presence of an air gap that the longitudinal cavities in concrete determine.
- Compliance with modern quality and reliability requirements. Products manufactured at industrial enterprises cannot be of low quality, since their production is carried out using a given technology.
- Accelerated installation. The installation of hollow-core panels takes less time than the installation of solid massive structures.
- A wide range of products with different sizes and configurations.
Contemporary slabs are made with cutting-edge technologies and are based on high-strength concrete. They can therefore be utilized in situations where there is a lot of seismic activity. The construction material will shield the building from moisture, steam, and gas if the installation guidelines are followed.
All of the surfaces in the house will be as smooth as possible if the supports are positioned correctly. The material requires little maintenance and is incredibly dependable and durable.
Each variety’s composition includes porous materials that increase resistance to freezing temperatures.
The slab can accommodate a variety of utility lines and channels because of its proper configuration. Furthermore, hollow-core constructions are impervious to various corrosion processes and do not fear shrinkage. Builders don’t need to install extra support posts when using them.
But, in addition to their benefits, the panels have drawbacks. First and foremost, there is the requirement for the use of specialized lifting equipment for installation work, which increases both the cost and the size of the construction site. To find the slab’s strength, mathematical computations are also necessary. Finding the wall’s allowable load and load-bearing capacity is essential before installation.
In order to create ceilings using hollow-core panels, the armored belt must be concreted around the box’s edge.
Technical characteristics
The following features of the multiple flooring panel are present:
- The bearing capacity per 1 m2 is 0.68 tons of permanent and 0.5 tons of temporary loads.
- Density indicators are determined by the type of concrete mix used in the production process. Specific gravity varies from 2 to 2.4 tons/m3.
- Concrete is capable of withstanding a number of compressive loads. Taking this property into account, the slabs are given the index B22.5.
- The degree of frost resistance corresponds to F200.
- Slabs can be used in environments with high humidity, since they have a water resistance level of W4.
- The dimensions of hollow-core slabs are determined by their design.
Additionally, slabs can vary in thickness. Regulations state that it needs to be at least 22 cm.
Load that hollow-core panels can withstand
The official documentation specifies the permissible loads on the slab, which are established by computing specific indicators:
- Static load of a permanent type. Such efforts include the presence of furniture in the building, equipment, partitions and insulating layers.
- Dynamic load of temporary type. This can be the movement of people or animals around the room, as well as the rearrangement of furniture and other movable structures.
Loads can act locally, sporadically, or at a point. In order to compute the allowable forces accurately, a building’s power scheme must be designed, the weight of the impact on the slab must be ascertained, and the total load must be obtained.
Reinforcement
The purpose of the reinforcement procedure is to improve the strength properties of the slab. Cement mixtures of grades M400 and M300 are added to their composition in order to achieve this. First, resistance to loads up to 400 kg/cm^/sec is guaranteed; second, the panel’s surface is shielded from deflections.
The reinforcement method, which consists of the following stages, is another way that reinforcement is carried out:
- Stretching stainless steel rods.
- Installation of a steel mesh.
- Pouring concrete mixture into formwork with reinforced elements.
- Trimming remnants of reinforcement protruding from hardened concrete.
Because tension reinforcement is used, the slab resists bending, sagging, and heavy static and dynamic loads. Double reinforcement is added to the ends of the reinforced concrete panel to increase its resistance to these kinds of actions.
When such reinforcement is present, maximum loads are protected against without deformation processes developing. The slab is in demand for the construction of multi-story industrial buildings due to these qualities.
Dimensions
It is essential to create some drawings and ascertain the dimensions of the hollow-core slabs, including thickness, width, and length, before beginning to install them. Moscow construction stores sell these products in the standard sizes listed below:
- Length indicators vary from 168 to 12000 cm.
- Width can be 98-148 cm.
- The diameter of the internal channel is 114-159 mm.
Each type of slab in this instance has a consistent thickness of 220 mm. As per the standard, it is permissible to produce individual projects with distinct performance attributes.
Marking
In reality, hollow-core slabs are not associated with any regulated brands. However, their description might mention a few parameters.
PK 15-13-10 PK is therefore identified by a number of technical features, including:
- 15 — length of the structure in decimeters.
- 12 — thickness in decimeters.
- The number 10 is the most important and indicates the permissible load of 10 kg per 1 dm2.
Hollow floor slabs are a flexible and effective option for many different types of building projects. Their special construction, which has hollow or void cores, considerably lowers their weight without sacrificing strength or durability. This makes them perfect for wide spans found in residential, parking garage, and commercial buildings.
These slabs are a sensible option for contemporary construction due to their technical qualities, which include their ability to support loads and their ability to insulate against heat. They lower material costs, expedite the construction process, and raise a building’s overall energy efficiency.
Hollow floor slabs come in a variety of sizes and types, so they can be customized to fit the needs of a particular project. These slabs offer a dependable and flexible solution that satisfies both structural and architectural needs, whether they are used for multi-story buildings, commercial buildings, or unique residential designs.
All things considered, hollow floor slabs are a crucial part of modern building, providing a unique combination of innovation and utility that raises the standard and sustainability of constructed environments. Their extensive application in a variety of projects highlights their significance and potency in contemporary building techniques.
