AVALIAÇÃO DA INFLUÊNCIA DO POSICIONAMENTO DO NÚCLEO RÍGIDO EM ESTRUTURAS DE AÇO: ESTUDO DE CASO
Palavras-chave:
Steel structures, Concrete core, Second order analysisResumo
One of the main ways of stiffening tall buildings or formed by slender profiles, case of multi-
storey steel buildings, are based on the introduction of the concrete core, capable of resisting both
vertical and horizontal efforts. Generally, this bracing subsystem is positioned around the service core
in the central regions of the building. However, architectural proposals accasionally lead to asymmetry
of the plant core, a factor that influences the capability of the structure to withstand lateral efforts, and
to the appearance of torsion. This work proposes the analysis of displacements, distribution of efforts
and overall stability of models of a twelve-story steel structure, with the indicated variations: 1) center
of gravity of the coincident concrete core and structure; 2) shear center of the concrete core coinciding
with the center of gravity of the structure; 3) asymmetric concrete core in relation to the two axes. The
models were analyzed in the SAP2000 finite element software, where the efforts were obtained in the
metallic profiles in linear and geometrically non-linear analysis by the process P-delta process and
displacements used to calculate second order efforts through the Effort Amplification Method
Applicants. For verification of the core and calculation of the coefficient γz was used the TQS software.
It was concluded that the core positioning influences the torsion efforts, which become more accentuated
by the increasing distance from the shear center to the action resulting from the lateral loads. For the
building under analysis, the greatest variation of second-order efforts occurred in the Amplification
Method of the Requester Efforts, but did not show considerable variations through the P-delta analysis
process and the enhancement method γz coefficient. The difference of efforts between the models was
basically die to the geometric distribution generated by the positioning of the concrete core.
