A) Since the producers of chromite beams sell them by the kilo, the heavier they make them, the more profit they get. Therefore, sometimes beams with a weight of two or three times the required weight are made and It is delivered to the customer and thousands of justifications are presented for this so that the consumer is also convinced that these heavy beams are made completely in principle and according to calculations. Unfortunately, some engineers encourage this because they do not know the calculations of this type of beams and cannot control the beams, so as not to build a weak beam. Most of the details of the chromite beams that can be seen in the executive plans of the structures fully support this and unfortunately, with this method, national funds will be buried in the roof of the buildings.
b) If the same manufacturers have a ceiling implementation contract with the customer, since they have to reduce their costs, they do the exact opposite with a 180 degree turn. In this case, since they still do not have the ability to calculate the beams, they make the upper wing of the beams slightly thinner so that it does not bend during the concreting of the beams (the reason for this is completely obvious to the experts), but they make the lower wing of the beams very weak and it is not important for them at all. It is not known what loads these beams should bear during operation.
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In the case of calculations based on metal beams in structures, it reduces the consumption of steel by 6%. 20% reduction in concrete on the roof in metal beams weighing one square meter with concrete with metal beams about 190 kg.
An important point in the discussion of lightening, which is unfortunately due to the lack of cooperation of the engineers and also due to the lack of time to calculate the structure based on Loading the roof, and it is noteworthy that it increases the cost and wastes national resources.
