Analysis of the main girder of the double-beam bridge crane with two trolleys

In this research, the problem of calculating the necessary static quantities of the main girder with the box crosssection of the double-beam bridge crane with two trolleys were analyzed. The aim is to determine the critical position on the girder due to the action of all loads in the vertical plane, as a function of input parameters, and to obtain expressions for calculating deflections in the vertical and horizontal planes, as well as bending moments in these planes, ie maximum (total) stress in the girder. Verification of the results was carried out in the SAP2000 software package, with proved a quite good correlation between the results obtained, for the proposed method of the calculation model of the box-girder, in the mentioned software package. The goal of this research is primarily to show how the application of the SAP2000 software package in an easy, fast and simple way can perform the dimensioning and design of this type of carrying structures, taking into account important static conditions that must be satisfied. By applying the proposed modelling method and using a certain module in the mentioned software package, the designer easily achieves the preliminary geometric values of the girder in the initial design phase, where he can completely rely on the obtained results. Also, all geometric quantities necessary for further phases in the design and calculation are obtained. Guidelines are given on how to prepare a calculation model in this software package for these types of carrying structures, as well as recommendations related to the design of these types of carrying structures made of S355 material.