Near-Source Ground Motion Selection With Fling-Step Displacement
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Solution Overview
Problem
Existing ground motion selection methods fail to adequately consider the fling-step effect in near-source strong motion records, leading to incomplete retention of permanent displacement information and errors in seismic response analysis due to manual interventions and filtering techniques.
Innovation Solution
A method and system for selecting near-source strong motion records that incorporate fling-step effects by using a multivariate conditional distribution framework, considering additional ground motion features like duration and cumulative energy, and employing Latin hypercube sampling and K-S tests to ensure accurate selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If standard baseline correction and band-pass filtering methods are used to process ground motion records, then processing efficiency is improved, but permanent displacement information is lost
Solution Approach 1:
The patent extracts and preserves the permanent displacement component from the ground motion record by using a baseline correction method that specifically targets and retains the fling-step effect, separating it from the noise that would otherwise be removed by standard filtering
Solution Approach 2:
The patent changes the processing parameters by using a high-pass filter with a very low cutoff frequency (0.01 Hz) instead of the conventional higher cutoff frequencies, allowing permanent displacement information to pass through while still removing high-frequency noise
2Reliability
If high-pass filtering is applied to remove low-frequency noise, then signal quality is improved, but permanent displacement information is removed
Solution Approach 1:
The patent changes the filter cutoff frequency parameter to an extremely low value (0.01 Hz), which is low enough to preserve the permanent displacement signal while still providing noise rejection. This parameter adjustment resolves the contradiction between noise removal and information preservation
3Ease of operation
If single ground motion intensity measure is used for spectrum matching, then selection simplicity is improved, but destructive capacity description is insufficient
Solution Approach 1:
The patent transitions from using a single ground motion intensity measure to using multiple intensity measures simultaneously. This dimensional expansion allows the selection method to capture both the amplitude characteristics (PGA) and the permanent displacement characteristics (fling-step amplitude) of ground motions, providing a more comprehensive description of destructive capacity
4Measurement precision
If manual intervention is used to determine split time points in multi-segment baseline correction, then correction accuracy is improved, but error accumulation occurs
Solution Approach 1:
The patent implements a self-service mechanism where the baseline correction method automatically determines the split time points and correction parameters without requiring manual intervention. This automated approach eliminates human error while maintaining correction accuracy through algorithmic optimization
Data Source
AI summary
A method for selecting near-source strong motion records considering fling-step effects includes the following steps: introducing a permanent displacement as a conditional parameter into ground motion selection based on generalized conditional intensity measures, and giving a target permanent displacement by extended probabilistic fault displacement hazard analysis; characterizing a frequency content component of a ground motion with a spectral displacement instead of spectral acceleration in a target ground motion intensity measure set; further calculating an empirical correlation coefficient suitable for near-source strong motion records with permanent displacement, constructing a corresponding target conditional distribution, and finally obtaining a data set of near-source strong motion records with permanent displacement most consistent with a target conditional distribution by optimizing selection from a near-source strong motion database. A reasonable ground motion selection method is provided for seismic response analysis of near-source engineering structures under a strong motion-fault dislocation coupled effect.