Bearing capacity of pultrusion fiberglass gusset sheets in frame structures

Introduction. At present, design and construction of all-composite structures with the use of pultrusion fiberglass profiles (PFP) are developing. The bearing capacity of all-composite structures is often limited by their node connections. Over the last two decades, many studies have been devoted to the operation of fiber-reinforced polymer (FRP) element nodes connected at right angles (or in the direction of pultrusion and across it). Frame construction nodes are formed by adjoining frame elements at different angles to the bands through gusset sheets. In accordance with the literature analysis, a small number of tests have been carried out to investigate connections at angles to the pultrusion direction. Existing design solutions of gusset sheets in FRP frame structures are mainly made of steel or composite material produced using other technologies (compaction method, pressure treatment method). This study focuses on the implementation of a node connection on unidirectional gusset sheets in which the fibers are positioned at the angle of 0°. Taking into account the specific features of the material, the gusset sheet design in frame structures has been adapted to the properties of pultrusion fiberglass. The purpose of this study is to increase the efficiency of PFP gusset sheet use in frame structures based on the specifications of this material. Materials and methods. The adaptive method was used when designing the node connection design on the frame structure gusset sheets. The material of the trapezoidal steel truss is changed to the composite material while retaining the original design solution. Subsequently, the structure is upgraded to take into account the properties and features of the composite material. Results. The main results of the study involve determining the factor of safety of pultrusion fiberglass at different angles to the direction of force. In order to increase the bearing capacity of the element node connection, various gusset plate design solutions are provided, which take into account different forces in the frame structure elements. Conclusions. When designing PFP constructions, features of the material must be taken into account. Replacing traditional materials with composite without adjusting the design layout and upgrading the structure leads to increased material intensity.