Thus, the cross bracing must be treated as a separate part since distinct geometric entities are required to model the bolted joints. Since these joints do not provide complete continuity for all degrees of freedom, separate vertices are needed for connection. The bolted joints, which connect the cross bracing to the truss structures, and the connection at the tip of the truss structures are different from the welded joint connections. For convenience, both truss structures will be treated as a single part. A single part is used to represent the internal bracing and main members. Therefore, you need only a single geometric entity (i.e., vertex) at each welded joint in the model. The welded joints between the internal bracing and main members in the crane provide complete continuity of the translations and rotations from one region of the model to the next. In the following figures, truss A is the structure consisting of members AE, BE, and their internal bracing and truss B consists of members CE, DE, and their internal bracing. The dimensions of the crane are shown in Figure 6≡1. The crane is welded firmly to a massive structure at points A, B, C, and D. The two truss structures are connected at their ends (at point E) in such a way that allows independent movement in the 3-direction and all of the rotations, while constraining the displacements in the 1- and 2-directions to be the same. Both the internal bracing and cross bracing use steel box beams with smaller cross-sections than the main members of the truss structures. These connections can transmit little, if any, moment and, therefore, are treated as pinned joints.
The cross bracing connecting the two truss structures is bolted to the truss structures.
Each truss structure is stiffened by internal bracing, which is welded to the main members. The two main members in each truss structure are steel box beams (box cross-sections).
The crane consists of two truss structures joined together by cross bracing.
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