The tallest structures today (commonly called "skyscrapers" or high-rise) are constructed using structural steel due to its constructability, as well as its high strength-to-weight ratio, which is the strength of a material over its density.
The cost of construction materials depends entirely on the geographical location of the project and the availability of the materials. Reinforced concrete derives about half of its construction costs from the required form-work. This refers to the lumber necessary to build the "box" or container in which the concrete is poured and held until it cures. The expense of the forms makes structural steel and precast concrete popular options for designers due to the reduced costs and time, as well as the loading of the lower structures.
I-beams (also known as H-beam, w-beam, or double-T beam, is a beam with an I or H-shaped cross-section) are usually made of structural steel and are used in construction and civil engineering.
Flanges & Web
The horizontal elements of the "I" are known as flanges, while the vertical element is termed the "web".
The height/deep of the I-beam from the outer face of one flange to the outer face of the other flange.
Nowadays, structural steel form-work can be finished in short time, and after the structual framing, lightweight aggregate precast concrete panels will be erected subsequently rapidly.
Commonly, the beam height of I-beam HE100A to I-beam HE160A is from 96mm to 152mm, lightweight aggregate precast concrete panels are designed with width from 90mm to 150mm, this make the lightweight aggregate precast concrete panels perfectly combined and embedding with I-beam structural steel while installing.