Use of recycled tires for earthquake protection of structures

The article presents numerous structures of earthquake-resistant foundations that have been developed by the authors and other engineers over the past more than 30 years, in which recycled metal-cord tires are used. The designs of dynamic dampers of dynamic vibrations, in which the containers for bulk fillers are made of recycled tires, are presented. Recycled tires are also effectively used in the creation of earthquake shields, as well as reinforcing elements and seismic insulation layers of earthquake-resistant ground dams. In all the above-mentioned technical solutions, the earthquake resistance of buildings and structures is achieved due to the unique geometric and physico-chemical-mechanical properties of recycled rubber tires with a metal cord.

Use of seismic insulation for seismic protection of railway bridges

The problem of seismic protection of the bridge for the conditions of Uzbekistan is considered. The bridge is located in an area with estimated seismicity of 9 points. It has massive high supports on a natural foundation and relatively small and light spans. When selecting seismic isolation, this made it possible to use the span structures as a dynamic damper for the support vibrations in the direction along the bridge. Due to the damping effect, it was possible to achieve that the seismic forces in the support in the presence of the superstructure were less than in the free support without the superstructure. At the same time, the rigidity of fastening the superstructure to the support increased in comparison with the rigidity of classical seismic isolation, which facilitated the design of the supporting elements.

Seismic Protection of an Over-Ground Parking Lot over the Dambovita River Using the Basic Insulation Method

Earthquakes cause rapid variations of direction, speed and acceleration. Vibrations are generated either by the moves of the tectonic plates, or by the volcanic activity, or by the collapse of the geological layers. The foundation conveys the maintained oscillatory movement and executes free cushioned oscillations. Due to the seismic action, an energy balance is created that contains: the energy induced into the structure, the energy absorbed by the structure and the energy returned to the ground. All these forms of energy constitute the capable energy of the structure. This energy reflects the possibilities of elastic structure deformation but also the elastoplastic deformation capacity. The seismic insulation systems are intended to reduce the impact of earthquakes on buildings by means of special devices. One uses two types of seismic systems: active and passive. The insulation of the propping base of the structure aims at inserting a smaller amount of energy into the superstructure. The protection of the structures exposed to the risk of earthquake is based on the three fundamental operational modes: insulation, connection, dissipation of energy. Connectors. Insulators and seismic dampers. The centrically braced metallic frames provide resilience, rigidity and ductility, being thus ideal for the bracing of the seismic systems.

Criteria for damping parameters optimization in seismic isolated structures

All kinds of seismic insulation systems are widely used to protect various structures and buildings, including unique ones, against earthquakes. The efficiency of such systems depends significantly on the competent selection of damping parameters. The article considers a general approach to selecting optimal damping parameters, both by the criterion of absolute accelerations and by the kinematic criterion. The optimization criterion for unique structures is also proposed.

Applicability of Commercial Software for Bridge Design with Consideration of Seismic Loading Effects

The construction of bridges with use of seismic isolation is a less-used concept in Slovakia and the Czech Republic. The concept of seismic isolation of bridges is a way of protecting bridge construction without damaging the pillars and substructure unlike the currently used methodology of consideration and development of plastic joints. When using this concept correctly, it is possible to prevent serious damage of construction and greatly reduce economic losses. Creation of a FEM (Fine Element Method) model, that is capable of correct description of the bridge behavior during a seismic event is often problematic. In this paper, the features of designing and modeling of bridge constructions with use of seismic insulation based on elastomeric bearings are presented. Furthermore, the calculations of stiffness constants required for numerical modeling are presented as well. In this paper are described methods of modeling of seismic isolations in a commonly and commercially available FEM based software. The work also contains a comparison of possibilities as well as limits of these programs. We further present recommendations for correct modeling by use of nonlinear material properties or elastic bonds between elements.

Settlement Researches of Seismically Isolated Buildings

The paper studies the efficiency of seismic isolation system in the form of rubber-metal bearings with different height buildings at multicomponent seismic impact. As an example, seismically insulated monolithic reinforced concrete 5-, 9-and 16-storey buildings are considered. The solution of the problem is obtained by a direct integration of the motion equations for an explicit scheme in the software package LS-DYNA. The calculation is performed considering nonlinear nature of rubber bearings. The analysis of the effectiveness of buildings with seismic insulation and without it is performed.