Análise da influência da ligação viga de transição-pilar em edifícios de concreto armado submetidos à análise incremental

Abstract

The populational increase, together with the densification of regions over the last few years in Brazil, has caused a frequent demand for housing in increasingly limited spaces. In addition, the growth of the vehicle fleet has also increased the value of commercial and residential buildings with large garage floors, restricting the positioning of structural elements, especially columns. As a solution, transition beams are used to transfer column stresses from upper floors to lower levels. The stresses acting on these beams are usually of high magnitude. In addition to this, there is also the possibility of neglecting the loads acting on the structure as a whole when carrying out a conventional analysis, considering the structure to be built and stressed at the same time. Considering that the structure is stressed throughout its construction provides more accurate results that are consistent with reality, a process known as the incremental effect. Therefore, this work seeks to analyze the influence of the transition beam-column connection in reinforced concrete buildings in terms of the overall stability of the structure, the magnitude of the redistribution of forces and the respective reinforcements required. It also evaluates the impact of the use of spherical plain bearings at the base of columns that rise on transition beams, a practice adopted by some designers but with limited published literature. To do this, 8 models were designed in the TQS software, 4 with 12 floors, identified as M02, and 4 with 25 floors, identified as M01. The structures adopted have a regular geometry, alternating between incremental effect considerations and the use of a ball joint at the base of these columns. The analysis was based on columns P8 and P30 and transition beams VT1 and VT2. The results of the coefficient z, total displacements and relative displacements between floors showed little or no difference between the models of the same dimensions, as well as being in accordance with the standard. In terms of normal stress, the differences occurred when comparing models with and without incremental analysis. The parameters evaluated that underwent the most significant variations when considering the incremental effect and/or the use of spherical plain bearings were bending moments and the reinforcement required to design the elements analyzed. The study also pointed out that, for the most part, the greatest stresses were obtained in the models that took the incremental effect into account. On the other hand, it was possible to see a sharp reduction in the reinforcement of columns that have their base labeled over the transition beams.