For a building equipped with anti-seismic devices, the value of the damping force of the dampers positioned at the superstructure is very important for an efficient anti-seismic damping and therefore an optimization of the seismic protection system with dampers is required. There are several configurations for placing the dampers that amplify the displacement and the damper axial force. This paper presents a computational mathematical model made for determining the coefficients of displacement multiplication and the damping force multiplication for two special positioning configurations of the antiseismic dampers using levers. Based on this model, a software program was created that allows to choose the geometrical parameters of two configurations of dampers placement having as criterion of choice the value of the amplification coefficient of the dampers displacement or the damper axial force.

To save the environment we need to recycle. In order to save natural resources we must recycle glass products. These recycled glass products are crushed and the necessary sorts are created, namely 0/4 mm and 4/8 mm, which we can partially replace from the aggregates of ballast or quarry needed to make concrete pavers. A study has been made on the mechanical strength of the pavers. The study consisted of making concrete paving stones, as well as making recipes with crushed and sorted recycled glass. The same tests were carried out to verify the products.In this paper we will present in parallel both the results on classic pavers and the results on recycled glass pavers, the so-called "firefly" concrete. The tests show that recycled materials can be used successfully but in well-defined proportions. These quantities of recycled materials are determined by physical and mechanical testing of the finished product.

In the paper presented are given oscillation amplitude threshold compaction and vibrating platform, stiffness and viscosity of the concrete, and the frequency and amplitude of movement on compacting concrete.

The paper is based on dynamic modeling research and experimental results obtained for freshly compacted concrete under stationary vibration. Thus, computational relationships and laws for vibration parameters and dissipated energy will be presented. In correlation with the dissipated energy, it will be evidenced by the evolution of the compaction degree and the resistance of the concrete depending on the vibration duration. It is noted that significant correlations have been established between the displacement curve of the dissipated energy and the loop hysteresis area for several vibration frequencies specific to the dynamic compaction regime

Abstract. The paper presents the rheological modelling of fresh concrete subjected to vibrations during the compacting process. The compacting efficiency can be estimated by means of the vibration transmissibility from the vibrating tool to the fresh concrete mass. Also the experimental results are presented.