Advanced Model of Spatiotemporal Mining-Induced Kinematic Excitation for Multiple-Support Bridges Based on the Regional Seismicity Characteristics

Abstract

In the paper, an advanced model of spatiotemporal mining-induced kinematic excitation (SMIKE) for multiple-support bridges exposed to mining-induced seismicity is proposed. The uniqueness of this model results from the possibility of its application in any region of mining activity, as it is based on empirical regression functions characterizing such regions. In the model, the loss of coherency resulting from the scattering of waves in the heterogeneous ground, the wave-passage effect originating in different arrival times of waves to consecutive supports, and the site-response effect depending on the local soil conditions are taken into account. The loss of coherency of mining-induced seismic waves is obtained by applying a random field generator based on a spatial correlation function to produce time histories of accelerations on consecutive structure supports based on an originally recorded shock. The deterministic approach is used to account for temporal wave variability. The proposed SMIKE model is applied to assess the dynamic performance of a five-span bridge under a mining-induced shock recorded in the Upper Silesian Coal Basin (USCB), Poland. The first model’s parameter (space scale parameter) is identified on the basis of regression curves defined for the USCB region. The estimation of the second parameter (the mean apparent wave passage velocity) is based on discrete experimental data acquired via the vibroseis excitation registered in the in situ experiment. The impact of the model application on the dynamic performance of the bridge is assessed by comparing the dynamic response levels under SMIKE excitations, classic uniform excitations, and the “traveling wave” model—accounting only for the wave passage effect. The influence of wave velocity occurs to be crucial, modifying (either amplifying or reducing, depending on the location of the analyzed point) the dynamic response level up to a factor of two. The introduction of the space scale parameter changes the results by 20% in relation to the outcomes obtained for the “traveling” wave only.

Optimization of the Crest Factor for Complex-Valued Multisine Signals

“…A heuristic and simple approach is to clip the absolute value of the complex values in the time-domain while keeping the phase. As a result, the clipping algorithms presented in (11) have to be modified to keep the phases for complex signals as:…”

“…Multisine test signals are used in various applications, such as testing of analog integrated circuits [6], electric drivetrains [7], impedance spectroscopy [8], [9], battery diagnosis [10], vibration analysis of bridges [11], or even wireless channel estimation [12], [13].…”

On the Susceptibility of Reinforced Concrete Beam and Rigid-Frame Bridges Subjected to Spatially Varying Mining-Induced Seismic Excitation

“…Eurocode 8 [11] recommends considering this effect for long bridge structures under seismic events. The spatially varying ground motion phenomenon is well recognized in regions with natural seismicity [12][13][14], but, to the best of the authors' knowledge, it is rarely referred to in the context of mining-induced tremors [15][16][17]. Also, most studies of bridges and other multiple-supports structures focus on their responses to spatiotemporal variation in ground motion resulting from natural earthquakes [18][19][20][21][22][23][24][25][26][27][28][29].…”