چكيده به لاتين
Abstract: Fire is a hazard that causes damage to human life and property. One of the concerns of human societies that has become more important in the 20th century is to have buildings that are safe from fire and damage caused by it. Steel joints play a key and vital structural role in maintaining the stability and resilience of steel frame structures both in normal and high temperatures. investigations carried out by research and industrial centers on fire incidents and progressive destruction of steel structures Under the effect of fire in recent years, such as: destruction of the World Trade Towers on September 11, 2001 in New York City and the catastrophic incident of the destruction of Plasco building due to fire in 2016 in Iran, has made structural effect of steel connections in the face of fire more clear. In this thesis, the performance of two conventional girder steel joints in a steel frame with one floor and one opening under the effect of fire (at high temperatures) has been evaluated. The connections examined in this research are: a Flush Endplate screw connection model (bending connection with end plate) and a beam and column welded connection model with two corners in the wing and two corners in the beam (Top-Seat-Web-Angel). Connections were modeled with the help of ABAQUS finite element analysis software, and then the simulated models were validated with experimental data obtained from previous experimental tests on this type of connections. The very good compatibility of these models with the experimental results and also the comparison of the structural behavior of the built models with the laboratory models confirmed the validity and accuracy of the models. After making sure of the modeling, the design, modeling and evaluation of the performance of two types of steel connection with the scarf plate and sub-series, once welded and once screwed (BFP and WFP) were done under the effect of fire, changes in shape and destruction criteria, including permissible rotation. and allowable deflection for both types of connections at high temperatures were investigated and compared based on the graphs of beam-time, beam-temp, rotation-time and rotation-temperature graphs. The obtained results indicated that the mode of destruction of both connections is the same and occurs due to the rupture of the weld connected to the scarf plate and the column wing. Also, the results showed that the WFP connection has a greater ability to withstand than the BFP connection, and this in Meanwhile, the BFP connection showed better performance rotation.
