Estimation of the Seismic Damage Potential of RC Frames Using Seismic Parameters

Variation of the fundamental period is regarded as one of the methods to assess the damage of the structures under earthquakes. The inter-relationship among seismic parameters and variation of the fundamental period can identify the potential structural damage of an earthquake. For this purpose, the present paper aimed to study the relations among main seismic parameters, incorporating a variety of information about ground motion and variation of fundamental period. Three RC frames were analyzed under far-fault earthquake records by nonlinear dynamic analyses and mathematical methods applied to assay the correlation between seismic parameters and variation of fundamental period. Based on the results, high correlations were observed between some seismic parameters and variation of fundamental period. Further, based on regression equations, new parameters with a very strong correlation with variations of fundamental periods were achieved, which can be regarded as appropriate indices to estimate the potential structural damage of an earthquake.

Simulation of dynamic response of vibroisolated object

This paper presents application of Finite Element Method in designing of a vibroisolated object. A model of power generator of 113 MW was chosen for the analysis. Such the generator is used in one of power plants in Silesia district. Several frequency domain dynamic analyses aimed at assessment of influence of vibroisolation on acceleration level of the generator foundation were performed. Three different models of the generator were considered. For the purposes of verification of the obtained results measured vibration accelerations were used.

THE COMPARISON OF THE DYNAMIC TESTS RESULTS FROM SENSORY PLATFORMS

The article deals with dynamic plantography, which is a popular diagnostic method focused on assessment of the foot condition during walking and to expose foot disorders. The aim of the paper is to discover whether it’s possible to do dynamic analyses on short platforms by using comparison of short and long sensory platform output. To get dynamic output were used ImportaMedica platforms, specific long platform Elegance and short platform Speed. Three subjects were involved in dynamic test on both platforms. The evaluated parameters were surface of the foot, maximum and average pressure, speed and gait line. By comparing these parameters the biggest difference was discovered in adapting walking because of the correct tread on short platform. When comparing the outputs from the long and short platforms, a longer duration of the right and left footsteps was recorded for all three subjects on the short platform.

Calculated assessment of the impact of geometric deviations from the design on the parameters of mechanical safety of building metal structures within the framework of scientific and technical support for construction

An important part of scientific and technical support of civil engineering facilities at a construction stage - evaluation of influence of fluctuations from a designed geometry onto mechanical safety parameters of load-bearing metal structures - is considered. A multi-tier structure (industrial frame tower) is employed to demonstrate main features of such an assessment. Given is an approach to an analysis of as-built documentation and to a choice of most significant fluctuations of structural metal elements from a designed geometry. Effect of erection sequence being taken into consideration, the so-called genetic non-linearity, during computational estimation of a stress-strain state of metal structures mounted with deviations from their design positions is investigated. Results of static and dynamic analyses of designed and as-built (with geometry fluctuations taken into consideration) models of the multi-level industrial frame tower are obtained and compared with each other. Basing on these results, guidelines for computational assessment of effects of fluctuations from a designed geometry onto mechanical safety parameters of similar frame systems are formulated.

A Comparative Study of Signal Processing Methods for Contactless Geodetic Monitoring

Building structures are subject to various deformations caused by external and internal factors. Deformations are determined by various methods in the form of monitoring. It is very important to monitor the dynamic vibration response on bridge structures since these measurements allow us to identify any possible damage over time and take appropriate action. Our experiment, described in this article, is based on the use of non-contact methods, among which we used a geodetic instrument RTS (Robotic Total Station) and a seismograph to measure vibrations. The purpose and novelty of our work are reflected in the use of geodetic instruments to determine the dynamic response and synchronization of the obtained results. When using RTS technology, we increased data acquisition from 9 to 26 measurements per second. Comparative analysis of the measured signals was performed using FFT (Fast Fourier Transformation) and LSP (Lomb–Scargle Periodogram), based on LSSA (Least-Squares Spectral Analysis). The results showed us that when using the RTS geodetic instrument, it is possible to achieve frequency spectra comparable to those measured with a seismograph instrument. By increasing the number of measurements, the RTS method can be used to obtain more continuous data, which are essential for dynamic analyses.