Can composite material be compared kilo for kilo against other materials?

The cost analysis will depend largely on the size of the structure. In the case of large structures, by using latticed solutions, a very efficient use of composite material can be achieved, and therefore be more competitive compared to other materials.

It is essential to know that the strength of composite material is superior to that of steel, but the elastic modulus is lower, so we must design for stiffness. Therefore, structural systems must have sufficient inertia to achieve the necessary stiffness and the minimum possible weight.

The last thing we verify is resistance, not the other way around, as is usually done in metal structures.

One variable to consider is that in composite materials we do not have the variety of profiles that exist in steel, so each specific case must be analyzed to reach the best possible structure.

It would be very difficult to use a cost-per-kilo comparator, since the weight of composite material is lower compared to other materials. For example, a 20x20 meter roof made of composite material can weigh up to 3 times less than a metal one; therefore, the cost analysis will depend largely on the size of the structure.

In general, there is no cost per kg of structure that can be applied generically, as it is advisable to carry out a prior analysis.

In addition, composite material is competitive for other reasons beyond price; in certain corrosive environments, or where dielectric, lightweight or electromagnetic wave-transparent solutions are required, a long-term cost analysis can be performed, which may generate a comparison between the initial cost and the maintenance of the structure.

In terms of initial cost, fiberglass structures can be comparable when compared to very heavy hot-dip galvanized or 304 stainless steel structures.

Then in the medium and long term, against the maintenance costs of the same.