Plieninių rėminių konstrukcijų pasiduodančių mazgų modeliavimo ir projektavimo metodų kūrimas

Abstract

The main parts of the framework are beams, columns and joints. Taking into account all structural members, the accurate behaviour of the joints is least considered in the design practice. This is the framework part, which behaviour is the most simplified. Framework calculations are still performed according to the assumption that joints are either ideally rigid or ideally pinned, in spite of the fact that majority of the joints is neither ideally rigid nor ideally pinned. The idealization of joints into ideally rigid or ideally pinned significantly simplifies the calculation and design, but herewith limits the possibility to obtain the real behaviour of the whole structure. Structural and economical benefit of using the semi-rigid joints is widely known. The real behaviour of the framework allows designing more proper and safer structures, herewith reaching the economical benefit. Incorrect idealization of the behaviour may lead to design of an uneconomical structure and decrease its safety. Recently, the topic of semi-rigid joints is increasingly investigated. Many investigations have been performed with different joints of steel frameworks. Majority of investigations have been performed, when the joints were under bending moment – the force that has the biggest influence on joint behaviour. Only particular types of joints that are mostly used in practice were investigated. Despite the progress in this area, usage of semi-rigid joints in design practise is still problematic. Till now it is not clear how to adopt the existing methods to the non-investigated types of joints in point of calculation and how to evaluate the influence not only of bending moment but also of axial force to the behaviour of joints. The objectives of this scientific work are – investigation of influence of bending moment and axial force influence to the joint behaviour; extension of component method for joint calculation taking into account the influence of bending moment and axial force; application of proposed method to design practice. Such type of the investigation work in the Department of Steel and Timber Structures of VGTU is performed for the first time, because the current problems are widely investigated neither in Lithuania nor in other countries. There is a lack of information about the adaptation of existing joint calculation methods for evaluation of axial force influence to the joints behaviour. Such information is necessary to obtain the higher quality of steel framework design. Consequently, it is purposeful to perform scientific investigations on this topic.