Efeitos da protensão na frequência natural de vigas de concreto

Abstract

The development of researches related to Structural Dynamics is no longer motivated just to understand the behavior of buildings in relation to seismic actions. This fact happened because there was an advance of materials and technologies used in the constructions, which allowed the construction of larger, more complex and slender edifications, that consequently needs a better knowledge of their structural functioning. To solve this requisite, the study of Structural Dynamics is a very useful and precise tool. Still, in the context of Civil Engineering modernization, the prestressing technique on structures has become an effective and useful technology to provide structural solutions, because it offers a good cost-benefit ratio. For these structures to function as expected and do not present pathologies, it is necessary to study their dynamic characteristics. This paper presents a study about the effects that the prestress force can cause in a concrete beam, mainly on natural vibration frequency. For this, it was carried out an analytical and experimental comparative study of a beam model. This comparison shows the analytical method produces consistent results with that observed experimentally, provided that is possible to quantify the stifness of structure. It was also noted that the prestress force wasn’t sufficient to increase the stiffness of the element and consequently did not alter their natural frequency. In addition, the influence of the prestress technique as structural reinforcement was analyzed.