The use of natural period of vibration as an indicator of the global second-order effects on reinforced concrete structures

• Grant number: 15/18450-8
• Support Opportunities: Regular Research Grants
• Start date: November 01, 2015
• End date: October 31, 2017
• Field of knowledge: Engineering - Civil Engineering - Structural Engineering
• Principal Investigator: Gustavo Henrique Siqueira
• Grantee: Gustavo Henrique Siqueira
• Host Institution: Faculdade de Engenharia Civil, Arquitetura e Urbanismo (FEC). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Recent research has indicate that, in substitution of traditional simplified methods to verify the displaceability of a structure, the natural period of vibration can be used as an indicator of susceptibility to global second-order effects. This technique assumes that the natural period of vibration and the global second-order effects depend essentially on the same variables - stiffness matrix and mass matrix of the structure - and therefore must be related. Actually, the verification and validation of this technique has been restricted to the study of steel structures. In this research project, due to the peculiarities and differences of concrete structures with respect to the steel structures, the development of simplified relations are proposed to consider directly the second-order effects in concrete structures based on their natural period of vibration. The effectiveness of this technique, using different structural configurations, will be verified by comparing the results of final design moments obtained using the simplified coefficient ³z and the results of nonlinear numerical analysis performed in SAP2000. The objective is to develop a simplified method to consider directly second-order effects on three-dimensional frames, thus eliminating the limitation of analyzing only plane frames with an approximate methodology. It is also intended to evaluate the applicability of the method on structures with any geometry in the plane, even for structures sensitive to torsional effects, wherein the fundamental period of vibration and its corresponding mode of vibration cause a twist on the vertical axis (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

REIS, DANIEL G.; SIQUEIRA, GUSTAVO H.; VIEIRA, JR., LUIZ C. M.; ZIEMIAN, RONALD D.. Simplified Approach Based on the Natural Period of Vibration for Considering Second-Order Effects on Reinforced Concrete Frames. INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS, v. 18, n. 5, MAY 2018. (15/18450-8)

F. F. LEITÃO; G. H. SIQUEIRA; L. C. M. VIEIRA JR.; S. J. C. ALMEIDA. Análise dos efeitos globais de segunda ordem em estruturas irregulares em concreto armado utilizando o período natural de vibração. Rev. IBRACON Estrut. Mater., v. 12, n. 2, p. 408-428, 2019-05-20. (15/18450-8)