Numerical analysis of the beam-column connection stiffness in precast concrete with welded steel angle

Resumo

The use of precast elements in civil construction has the main advantag of expediting the structures construction process, as well as increased technological control of the materials used. Despite this, precast structures presente a discontinuity in the connections between the elements, such as between beam and column. This has become an important object of study, where we seek to improve the continuity of these regions, ensuring better distribution of loads and increasing the stiffness of the connection. Therefore, the objective of this study is to analyze, using numerical methods, the stiffness of the beam-column connection in precast concrete using a steel angle welded to the beams and column. To achieve this goal, the structure will be modeled using the Finite Element Method. A structural system composed of two beams and a column with the steel angle welded to the elements in the connection region. The angle is employed to assure a level of continuity in the connections between structural elements and increase its rigidity hence creating a with semi-rigid condition. The result of the numerical model will be verified with a proposed analytical model, considering the existence of a spring in the connection that guarantees the increased stiffness, reducing rotation in the support. From the rotation predicted in the numerical model, we can estimate the rotational stiffness and apply it to the analytical model for comparison and validation. In the numerical model, 4 analyzes will be carried out, the first analysis wont have the welded angle. The other three analyzes will be carried out with the welded angle, changing the weld area on the column and beams. Finally, the results are expected to demonstrate that the application of the welded angle on the beam and column presents better performance for semi-rigid connection, bringing greater rigidity to the connection, reducing the existing rotation and achieving a better redistribution of loads, thus ensuring a lower maximum positive bending moment for the beam. It is also expected that angles with larger weld areas guarantee greater rigidity for the connection than those with smaller weld areas.