Does Stronger Concrete Make Stronger and More Resilient Elements?

Abstract

Over the last few decades multistory buildings have been designed using gradually stronger and stronger concrete. The obvious advantage of increasing the material strength is the ability of the designer to reduce section area of some members without sacrificing strength. This paper takes a broader view in that it examines a number of mechanical characteristics of a structural member that had been thinned-down because of stronger concrete. Apart from nominal strength there is the elementary quantity of elongation at failure, which limits the deflection that can be attained. Other properties of concern are: Natural frequency, deflection under static and dynamic lateral loading, dynamic bending moment response under lateral loading and, above all, the amount of energy absorbed prior to the beginning of failure. The importance of the latter comes from the fact that when some elements are subjected to extreme loads, they are certain to fail, but the amount of energy absorbed by their destruction may be decisive for the survival or collapse of the entire structure. A distinction is made between prescribed lateral loading and a prescribed pressure applied. The paper uses simplified methods of comparison, which makes it possible to reach clear conclusions related to the advantages and disadvantages of employing high-strength concrete.