The research paper presents a novel approach toward constructing motion equations for structures with attached MTMDs (multiple tuned mass dampers). A primary system with MDOF (multiple dynamic degrees of freedom) was reduced to an equivalent system with a SDOF (single degree of freedom) through the modal approach, and equations from additional MTMDs were added to a thus-created system. Optimization based on ℌ₂ and ℌ_∞ for the transfer function associated with the generalized displacement of an SDOF system was applied. The research work utilized GA (genetic algorithms) and SA (simulated annealing method) optimization algorithms to determine the stiffness and damping parameters for individual TMDs. The effect of damping and stiffness (MTMD tuning) distribution depending on the number of TMDs was also analyzed. The paper also reviews the impact of primary system mass change on the efficiency of optimized MTMDs, as well as confirms the results of other authors involving greater MTMD effectiveness relative to a single TMD.

The purpose of this paper is to present methods of vibrations damping coefficient determination. The methods, such as collocation method, two energetic methods and half-power bandwidth method concern composite structures. The verification of methods has been taken into account in this work. Two real compound models and two numerical models have been created. Time series of vibrations of these models have been measured and calculated. The comparison of four methods has been made on the basis of obtained results.

The publication focuses on the issue of inventory surveying of façade scaffolding. The authors considered various land surveying methods such as photogrammetry, laser scanning or total station. To test these methods, sample measurements were performed on the deployed scaffolding. Specific equipment was used: GOM Tritop system with invar scale patterns, Leica C20 scanner and Leica TS50 total station. The authors present arguments for and against mentioned methods and also an analysis of the measurements of 10 scaffoldings. Finally, as a leading method the total station was chosen. The results of the tests and analyses confirmed that the accuracy of the selected method is 3 mm for the width and 3.6 mm for the height of the frame. Research material was collected from April to November 2016, with the use of Leica TS50 total station (1cc, 1 mm + 1 ppm), by one surveying team.

The paper presents FEM analysis of the wind action on overhead transmission power lines. The wind action is based on a stochastic simulation of the wind field in several points of the structure and on the wind tunnel tests on aerodynamic coefficients of the single conductor consisting of three wires. In FEM calculations the section of the transmission power line composed of three spans is considered. Non-linear analysis with deadweight of the structure is performed first to obtain the deformed shape of conductors. Next, time-dependent wind forces are applied to respective points of conductors and non-linear dynamic analysis is carried out.

A mathematical model of structure with multiple tuned mass dampers (MTMD) is presented in this paper. An important difficulty, connected with these model, is building a global damping matrix of the system. The own proposals of FEM elements describing additional elements attached to the main system in the form of tuned dampers are presented here. The benefits of the new FEM elements are briefly discussed.