Reinforced concrete beams

Modern construction requires the use of reinforced concrete beams. These beams are perfect for supporting large loads in buildings and bridges because they combine the durability of concrete with the strength of steel. Steel reinforcement increases the tensile strength of concrete, enabling the construction of stronger, longer-lasting structures.

There are many benefits to using reinforced concrete beams in construction. They need very little maintenance, are fire resistant, and are incredibly durable. They are therefore an affordable option for a variety of projects. They can also be utilized in a variety of settings, from big commercial buildings to residential residences, thanks to their adaptability.

A basic understanding of reinforced concrete beams can assist engineers, builders, and homeowners in making well-informed decisions regarding their application. For those who are interested in contemporary construction methods, this article will provide a clear and thorough overview of the salient characteristics, advantages, and typical applications of reinforced concrete beams.

Definition

A beam is a product made of reinforced concrete that has reinforcement. It supports the weight of floor slabs and other components and acts as a horizontal connector between vertical structures (walls, hangers, and columns).

Materials and characteristics

Based on concrete (heavy) classes (for compression) ranging from B22.5 to B60, their strength is determined. A thermomechanically hardened and hot-rolled metal rod reinforcement with a periodic profile, reinforcing steel ropes, hardened steel drawings of the specified classes, and wire of different strengths are all used in the reinforcement of products.

A reinforced concrete beam needs to have attained the minimum concrete strength, which is determined by three factors: transfer, design, and release (70% and 85% in warm and cold weather, respectively). These products exhibit high levels of resistance to fire, moisture, and aggressive gas compositions, as well as anti-corrosion properties.

Final goods exhibit high compliance levels in terms of strength, stiffness, and resistance to cracks. Even the standard tolerance sizes of no more than 3 mm are used for the positioning of reinforcement outlets (welded to the column reinforcement) on the exterior. Welding the end connecting plates and rods to the internal axial reinforcement creates a strong connection.

Purpose

Beams, which serve as supports for floor slabs, join the vertical structural components of buildings. This function helps the welding-united building reinforcement to form a rigid spatial strength. By shifting the weight of horizontal structures onto the supporting vertical "skeleton" of the building, these structures ensure the geometric stabilization of the structure as a whole. These products can be used to strengthen and unload the last, as well as raise the base over the foundation to the desired height. They are employed to assemble buildings with expansive floor plans (such as hangars and trading halls) and to reinforce the columns in spaces with tall ceilings.

These components, whether arranged as beams or used as columns, are made to support heavy loads. Window commissors, fences, and reinforced concrete crossbars in multi-story buildings can all be formed. A modified crossbar with a length of 12 meters is utilized in the construction of structures with a higher floor count and particularly large dimensions.

Compared to steel samples, this variety proved to be more dependable. Crossbars are actively used in the construction of transportation infrastructure, such as bridges, viaducts, parapets, transitions, and fences. Products are used in the energy sector to expand the load-bearing base of power transmission line masts. This enables loads to be distributed horizontally, increasing the supports’ bearing capacity.

Modern construction requires reinforced concrete beams because they provide the ideal balance of strength and flexibility. These beams are affordable, long-lasting, and capable of supporting large loads. In order to provide safety and stability for buildings and bridges, reinforced concrete beams combine the tensile strength of steel with the compressive strength of concrete. Because of this, they are a well-liked option for architects and builders searching for sturdy and dependable structural solutions.

Peculiarities

Their designs differ depending on the particular application site in terms of profiles, materials, cross-sectional area, and fastening technique. The samples’ cross-sectional shapes are a rectangle, a T-shaped one without shelves, and a brand with one or two shelves (for floor slabs). Slabs on one side can be supported by the one shelf option (end bay of a building, flight of stairs).

Two slabs support a model with two shelves (typical for central spans). T-shaped alterations with a low shelf lessen the structure’s visible exit into the surrounding area. With rectangular crossbars, the weight is just positioned above. Crossbars must be fastened to buildings using either rigid or hinged methods due to their structural characteristics and intended uses.

Marking

Products are marked with a alphanumeric code separated by a dash into groups. Example – RDP 6.56-110АIV. The 1st group indicates the type of beam, its cross-sectional height and length (dm), rounded to whole numbers. It is allowed to replace the contents of this group with the name of the product – beam ("P") indicating the standardized size. The second – provides information on the bearing capacity (in kN / m) of the product or its serial number by bearing capacity. Next, for prestressed reinforcement, the steel class is indicated (Latin letter and Roman numeral).

As a result, the product’s RDP 6.56-110AIV marking denotes the following: type RDP – beam for reinforced concrete hollow-core slabs, height 600 mm, length 56 mm, bearing capacity 110 kN / m, and steel class A-IV laid inside. The third set of designations, which describes the unique circumstances under which the product is suitable for use, is applied in certain situations. For instance, resistance to harsh environments, gases, and seismic tremors are covered here. Additional embedded part installation may also be considered.

Products with the RDP 6 marking.56-110AIV-Na, for example, in the 3rd group indicate that the product material is concrete with normal (“N”) permeability (permissible for use in slightly aggressive gaseous environments), inside which additional embedded elements (“a”) are installed. Beams by type are designated by letters: R – rectangular, RO – single-shelf (ROP – for hollow-core slabs, RLP – for flights of stairs, ROR – for ribbed slabs, RLR – similar to RLP), RB – shelf-less in the form of the letter “T” (RBP – for hollow-core slabs, RBR – for ribbed slabs), RD – double-shelf (RDP – for reinforced concrete hollow-core slabs, RDR – for ribbed slabs) and RKP – balcony (cantilever) for hollow-core slabs. Beams with the abbreviation are also found manufacturer (according to TU), taking into account the specifics of their shape, for example, RV, RM, AR, etc.

Difference between a crossbar and a beam

The beam can be considered a horizontal beam with special load-bearing functions (accepts loads from any direction) as the main supporting element of the building frame. It is a horizontal part of the frame, which is rigidly connected to the vertical posts of the main supporting structure (not subject to calculation). A beam laid horizontally or at an angle works as an independent structural unit of the building frame, only mainly in bending (calculated during design). Beams and girders cannot be interchanged, since the former are monolithic (reinforced concrete or metal), have a large weight, rigidity and strength, and the latter, as a rule, having a small mass, are made of wood or hollow metal structures.

Although the beams have a limited range of applications, their functionality is substantial. A reinforced concrete beam has a specific function that it always serves, no matter what the circumstances. However, the term "beam" has a broad definition that encompasses the beam. In the construction industry, beams are used for coverings, floors, or their support (an attic serves as an example of a structure whose primary purpose is to distribute the load of beams with rafters on the beams).

How to make a beam?

A reinforced concrete beam can be cast right there on the construction site. In wooden or frame buildings, a heavy monolithic product should not form a frame. Its application will necessitate a more meticulous foundation strength calculation. Strong formwork is constructed during the preparatory phase to establish the precise geometric dimensions and shape using stiffeners. The sides of the form are made of thick, moisture-resistant plywood, while the bottom is formed by metal sheets, or boards.

The form is leveled and placed on T-shaped supports made of boards. Roofing felt (film) is carefully applied to the bottom and interior walls. The number of upper and lower reinforcement frames formed in a beam depends on its length and the loads applied to the reinforced concrete structure. The upper edge of the lower frame should be situated 3 cm below the level of the upper cut of the form, and the lower edge should be at least 3 cm above the bottom. Before being installed within the form, reinforcing frames are formed outside of it.

The longitudinally oriented bottom reinforcement, which bears the tensile load, is made continuous and has a minimum diameter of 1 cm. The frames are wire-tied and welded together. In the middle third of the length, the lower longitudinal reinforcement is not joined, and in the outer quarters, the upper longitudinal reinforcement is. Sand, cement, and water are combined in a ratio of 4/2/1 to create concrete mortar. Continuous pouring is done while a vibrator is used to ram the mixture. Depending on the season, the product’s concrete needs are met during the first seven to ten days.

After two weeks, the side shields are taken off, but the lower beam support is left in place for a full 28 days. Next, an instrument is used to check the concrete’s quality. Following a complete set of grade strength, the beam is loaded if the outcome is positive.

Because they combine strength and flexibility to suit a variety of structures, reinforced concrete beams are a crucial part of contemporary construction. They offer a strong and resilient framework for infrastructure and buildings by fusing the tensile and compressive strengths of steel and concrete.

Because of their substantial load capacity, these beams are perfect for supporting roofs, floors, and bridges. Because of their adaptability, they can be made into a wide range of sizes and shapes to satisfy unique structural and architectural needs. For ensuring stability and longevity, reinforced concrete beams are a dependable option that can be utilized in residential, commercial, or industrial projects.

Professionals and do-it-yourselfers alike can benefit from having a basic understanding of reinforced concrete beam construction and realize how important these beams are to the structural integrity and safety of buildings. Every stage of the process, from careful material selection to precise placement and curing, adds to the durability and performance of the beam.

In conclusion, reinforced concrete beams are a vital component of contemporary building, offering resilience and support. Because of their versatility and capacity to withstand a wide range of loads and conditions, they are essential in many different applications and guarantee the long-term safety and functionality of structures.

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