Banca de DEFESA: LÁZARO SABAS MARQUES SILVA CHELES NASCIMENTO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LÁZARO SABAS MARQUES SILVA CHELES NASCIMENTO
DATE: 17/02/2023
TIME: 09:00
LOCAL: Google Meet - https://meet.google.com/ibi-kkwr-goz
TITLE:

Evaluation of vibration in prestressed reinforced concrete beam when periodically excited

KEY WORDS:

Mathematical modeling; Computational model; Vibration; Fluency; Geometric stiffness; Prestressed concrete

PAGES: 93
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

Through mathematical modeling and a computational model, this work verified the existence of resonant and non-resonant regimes in a double-supported prestressed reinforced concrete beam, when periodically excited. Aiming to prove the hypothesis that prestressing changes the natural frequency of the structure. This dissertation considered both the geometric aspect, through the concept of geometric stiffness, and the behavior of the material, through a time-varying modulus of elasticity, capable of considering the creep of the concrete. It is known that the dynamic characteristics of the structure basically depend on its stiffness and mass. With these elements, the natural frequencies and vibration modes of the system are determined. However, the initial stiffness of a structure can be affected by the so-called geometric stiffness, a function of the acting normal stress. When prestressed beams are subjected to rotating loads, the design must move the system's natural frequencies away from the excitation frequencies to avoid structure resonance. Unexpected, potentially dangerous resonance regimes can occur when the prestressing force decreases the rigidity of the structural element, altering its natural frequencies. To evaluate these aspects, a mathematical equation with formulations based on the Rayleigh method was proposed, with creep being considered by the criteria of the concrete standard NBR 6118 of ABNT (2014). The results indicated the resonant and non-resonant regimes predicted in the mathematical considerations.

COMMITTEE MEMBERS:
Presidente - ***.925.915-** - PAULO ROBERTO LOPES LIMA - UFBA
Interno - ***.925.915-** - PAULO ROBERTO LOPES LIMA - UEFS
Interno - 2178571 - RICARDO FERNANDES CARVALHO
Externo à Instituição - GUSTAVO HENRIQUE SIQUEIRA