Reinforced concrete floor beams

In today’s construction, reinforced concrete floor beams are vital parts that give buildings the necessary stability and support. These beams are essential to the structural integrity of floors and roofs in both residential and commercial buildings because they are made to support heavy loads over extended spans.

The composition of reinforced concrete floor beams, which consists of both concrete and steel reinforcement, is what makes them unique. The majority of the beam is composed of concrete, which is renowned for its compressive strength. To improve tensile strength, steel reinforcement rods or bars are embedded within the concrete. This combination ensures durability and safety by enabling the beam to resist bending and cracking under high loads.

The versatility of reinforced concrete floor beams in terms of design and construction is one of their main benefits. It is possible for engineers to modify the beams’ dimensions and reinforcement to meet particular structural needs, which gives architects and load-bearing capacities more flexibility.

To support the weight of the structure above, these beams are usually positioned horizontally between columns or walls. They serve as the structural framework for floors and ceilings in multi-story buildings, offering a reliable platform for a range of applications, including homes and offices.

Furthermore, reinforced concrete floor beams greatly increase a building’s overall resistance to weather-related events like hurricanes and earthquakes. Their resilient design and capacity to rebalance loads help avert catastrophic failure, which makes them a top option in areas vulnerable to earthquakes or unfavorable weather.

Comprehending the fundamentals of reinforced concrete floor beams is essential for both architects and builders to guarantee the structural soundness and security of constructions. Building experts may design areas that are not only practical but also safe and long-lasting for users by carefully integrating these beams into their plans.

Advantages and disadvantages of reinforced concrete beams

A highly resilient building material, heavy reinforced concrete can withstand large loads under compression, bending, and torsion. Furthermore, producing this product is substantially less expensive than producing rolled steel I-beams or channels.

The advantages of reinforced concrete floor beams were determined by these and other factors.

• Ability to bear several times greater loads compared to wooden analogues.
• High rigidity allowing to cover large spans.
• Resistance to harmful atmospheric and biological factors: moisture, corrosion, fungi and woodworms.
• Resistance to open fire.
• Lower cost of manufacturing compared to floor beams made of rolled steel.

• The large weight of the product that determines the high “own” load on the walls and the foundation.
• The need to use special construction equipment when unloading and installing the product.
• High thermal conductivity compared to wooden analogues.
• Economic inexpediency of use in the construction of single-story private residential buildings. Floor beams of a single-story house take the load from the elements of the rafter system, roofing material and the material from which the floor is made (usually two layers of boards insulated with basalt wool and plywood). This is a relatively light-weight structure, which can be more than supported by floor beams made of solid wood.

Features and dimensions of reinforced concrete floor beams

Floor beams are made using heavy or light structural concrete reinforced with hot-rolled or thermomechanically strengthened reinforcement of class A600-A1000, in compliance with GOST 20372-2015 requirements.

In addition, the sizes listed in Table must match the standard sizes of GOST 20372-2015 reinforced concrete floor beams.1.

Depending on the length of the floor, the following categories of load-bearing products are governed by the normative document GOST 20372-2015:

• Reinforced concrete floor beams of the BSP6-BSP9 series covering spans of 5960-8960 mm.
• Products marked 1BSP 12-2BSP12 covering spans of 11960 mm.
• Rafter beams 1BSD18 permitted for the construction of a span of 17960 mm.
• Beams of the 1BSD15 series for the construction of spans of 14960 mm.
• Beams of the 1BSD21 series used for the construction of 20960 mm long floors.

The product type is referred to above by the following designations: BSD (gable rafter beam with parallel chords) and BSP (rafter beam with parallel chords).

Reinforced concrete floor beams are essential for maintaining structural durability and integrity in the construction industry. These beams are crucial parts that evenly distribute loads throughout spaces and support the weight of buildings. It is essential that builders, engineers, and architects all understand their materials, installation techniques, and designs. The main features of reinforced concrete floor beams are examined in this article, along with their practical uses in contemporary building and fundamental theories. We learn how these beams contribute to the strength and stability of concrete structures by exploring their significance and functionality, which makes them essential in the built environment.

Load for reinforced concrete beams

This value is typically specified in the working documentation’s technical requirements and specifications for the construction of a particular building or structure. Based on the unique loads on the building elements, the design engineer performs a preliminary calculation. Then, the result is multiplied by the safety factor, and the floor beam’s parameters are included in the working documentation. To put it another way, every object has a unique dimension for the floor beams and other building components.

It can be suggested that private developers, who frequently construct their buildings without a project, use the empirical method below to determine the dimensions of concrete floor beams:

• The initial value for the calculation is the span length between the load-bearing walls or the load-bearing wall and the load-bearing partition. For example, the span length is 5,500 mm.
• We calculate the height of the cross section. The minimum height should correspond to 1/15 of the span length: 5,500/15 = 366 mm. We take the value closest to 366 mm from the values ​​of available reinforced concrete products.
• We calculate the width of the cross section. The width of the cross section should be at least 100 mm and calculated using the following formula: section height/2…4. Thus, 366/3=122 mm, where "3" is the arithmetic mean of 2…4. The obtained result is also rounded to the nearest larger value of the width of the available product.

Note: Because the above-mentioned calculation scheme accounts for the safety factor, engineering calculations of the beam section based on particular initial data regarding the product’s load value may differ negatively.

Reinforcement of a reinforced concrete floor beam

In the following systemic cases, reinforcing a completed reinforced concrete structure under operation might be necessary:

• Partial destruction and exposure of the reinforcement belt of the product, due to harmful atmospheric and other factors.
• Additional floors or levels (increase in load on the beam).
• Design errors led to the appearance of harbingers of the destruction of the structure: longitudinal and transverse cracks, exfoliation and collapse of parts of the structure of the structure.

The goal of reinforcing floor beams is to reduce the load or increase the product’s cross-section by adding extra components like portal frames, unloading brackets and struts, and columns (posts).

The product’s cross-section is expanded by:

• Building up the beam body with concrete from below. The technology is implemented by installing formwork for the lower part of the product, additional reinforcement and pouring concrete mixture.
• Reinforced concrete collar. In this case, the formwork is installed along the entire perimeter of the cross-section along the entire length of the beam. During the installation of the formwork, an additional reinforcement belt is formed, connected to the standard reinforcement belt. Ultimately, the resulting "pie" is concreted in one way or another.

Furthermore, reinforced concrete products are strengthened by construction and repair companies using rolled steel straps to reinforce the outer surface of the beam.

• sheet reinforcement on a polymer solution and anchor bolts;
• steel angles welded to the standard reinforcement;
• additional reinforcement bars located in specially cut grooves subsequently filled with polymer concrete;
• steel truss ties and ties made of reinforcing steel.

It is important to remember that the type of floor beam reinforcement should be chosen based on the findings of the site inspection and engineering calculations.

Reinforced concrete floors on metal beams

Rolled steel is occasionally used as I-beams and channels for floor beams that are then covered in concrete slabs. If it is not possible to buy prefabricated or solid reinforced concrete floor beams, this is a workable alternative.

For instance, as of this writing, 9,000 rubles will get you a brand-new concrete beam with a 220×180 mm cross-section and a 6,000 mm length. Simultaneously, an I-beam No. 18 used in similar length (6000 mm) and bearing capacity costs 39,500 rubles. When all other factors are held constant, the price difference is ten times greater. Product cost information is sourced from publicly available sources. This situation needs to be considered when planning and erecting structures.

Conclusion

To sum up, it is important to remember that proper economic and strength calculations are required to verify whether utilizing reinforced concrete floor beams produced at precast concrete plants in the construction of low-rise buildings is feasible.

Practice demonstrates that floors made of logs or wooden beams treated with compounds that prevent damage from fungi and woodworms are permitted in 90% of low-rise buildings with a height of one or two stories.

Modern construction relies heavily on reinforced concrete floor beams, which provide sturdiness and strength to buildings of all sizes. These beams can span considerable distances without sagging or cracking under heavy loads because they combine the tensile strength of steel reinforcement with the compressive strength of concrete.

The adaptability of reinforced concrete floor beams is one of their main benefits. They are appropriate for a variety of building styles and architectural designs since they can be made to accommodate different loads and support conditions. These beams ensure the stability and longevity of the structure whether they are used in commercial, industrial, or residential settings. They offer dependable support.

The function that reinforced concrete floor beams play in boosting fire resistance is another significant feature. In contrast to steel-only constructions, where elevated temperatures may cause the beams’ integrity to deteriorate, reinforced concrete beams offer efficient fire protection due to their concrete encasement. This building is essential for protecting inhabitants and reducing damage in the event of a fire.

Additionally, floor beams made of reinforced concrete support environmentally friendly building techniques. The main component of these beams, concrete, comes from readily available resources like clay and limestone. Furthermore, because reinforced concrete is long-lasting, there is less need for regular replacement or maintenance, which lessens the environmental impact of building lifecycle management.

In conclusion, because of their durability, adaptability, fire resistance, and strength, reinforced concrete floor beams are essential parts of contemporary construction. They are essential for maintaining the structural integrity and safety of buildings of all shapes and sizes, as well as for promoting sustainable building methods. Reinforced concrete remains a fundamental material that meets the demands of modern architectural and engineering challenges even as construction technologies advance.

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