A beam is a prefabricated member consisting of concrete and steel, which is produced in two types: prefabricated beams and truss beams. Arrows are subjected to force in two stages: The first stage: during the transportation of the beams and the execution of the roof. The second stage: after removing the roof concrete and collecting the piles
truss beam
The prefabricated truss consists of a steel truss and a concrete heel. The concrete mold has a metal heel, and if a permanent mold (foundole) is used, it is called a shoe truss beam.
Pre-tensioned beam
To create prestressing in beam concrete, usually several strands of steel wire with a diameter of 5 mm, with an ultimate strength of 17,500 to 19,000 kg/cm2 are used. The wires are stretched to 65% of their final strength before concreting. After concreting and obtaining sufficient strength in concrete, and creating a proper connection between steel and concrete, they are slowly released so that the beam is subjected to compressive stress. The concrete cover on the steel wires is at least 20 mm in all directions, and the distance between the two adjacent wires is such that the largest stone grain of concrete can easily move through them. The location of the wires is chosen so that the compressive stress in the lower part of the beam is higher than the stress in its upper part. Prestressed beams usually do not have transverse reinforcements. But in some of its types, in order to strengthen the shear strength of the two ends of the beam, transverse rebars are placed inside the concrete of the beam as shown below, so that in addition to the shear reinforcement of the beam, they provide the necessary clamps for transporting the beams.
Types of beams
There are common types of joists, which in Iran are Kermit joists or metal joists and concrete heel joists or block joists. Standard beam
Standard joist refers to a joist whose production steps are based on standard standards. Niazi industrial joist standard joist is produced based on Iran's national standard and national building regulations and has a standard mark permit. Standard joist includes standard Kermit joist and joist The standard block or concrete beam is standardized and the finished products are checked by the quality control unit.
The price of the beam
The price of cermet beams and the price of concrete block beams in Tehran and Iran is dependent on the daily price of cement, iron and rebar, so you, dear customers, can check the current price of beams using the online beam price calculation software on Niazi Industrial Beams website. And if needed, receive and pay the corresponding pre-invoice.