The paper investigates the potential of adopting the spectral acceleration S
a
(T) as an efficient measure for the estimation of the seismic performance of bare and infilled R/C buildings within the ...context of Performance-Based Earthquake Engineering. A large number of planar R/C buildings with different masonry infills' distributions are analyzed using nonlinear time-history analyses. The correlation between several damage measures and the S
a
(T) for a wide range of periods is investigated. The results point out the conditions under which the S
a
(T) can be used as an efficient parameter that describes adequately the damage response of bare and infilled R/C frames.
Typical transmission line steel lattice towers are not designed for seismic excitations, based on the assumption that their ultimate limit state is governed by climatic actions (wind and ice). ...However, it is not unusual for line inspection reports to indicate the observation of moderate to severe structural damages after intense ground motions, which can ultimately reduce the capacity of tower elements. Performance-Based Earthquake Engineering (PBEE) assessment is a modern technique to earthquake resistant design frequently adopted for building frame structures, but not yet employed in the design of transmission line supports, to the best of the authors’ knowledge. The present article evaluates the seismic performance of two typical 230kV transmission towers in a PBEE framework, considering artificial and actual ground motions based on Chilean seismicity. Time-domain nonlinear dynamic analysis is employed to numerically obtain tower responses considering distinct earthquake loading scenarios according to two model configurations: stand-alone and tower-line section. Significant structural damage was detected even for moderate ground motions, which might reduce the tower capacity to future climatic events. The estimated failure probability for the ultimate limit state was found greater than the recommended values in the standard IEC 60826 (2017).
•Performance-Based Earthquake Engineering assessment of transmission towers is carried out.•Time-domain material and geometrical nonlinear dynamic analysis is employed.•Two typical 230 kV are assessed considering based on Chilean seismicity.•Significant structural damage was detected even for moderate ground motions.•The estimated failure probability for the ultimate limit state was greater than recommended values.
•A dataset comprising 21 planar slender RC walls is presented.•Material model modifications are required to predict displacement capacity.•Accurate simulation of displacement capacity requires ...regularizing material models.•Unconfined/confined concrete crushing energies are recommended for regularization.•Response is simulated well with force-based elements and regularized material models.
The research presented here developed a model for simulating the nonlinear cyclic response of flexure-controlled concrete walls, which meets the dual objectives of accuracy and computational efficiency. The proposed model represents a significant advancement in that it provides accurate simulation of the dominate failure mechanism exhibited by flexural walls in the laboratory and field: compression-controlled failure characterized by simultaneous crushing of concrete and buckling of longitudinal reinforcement. The first steps in the model development effort comprised assembly of an experimental database and review of current modeling approaches for walls (e.g., lumped plasticity, distributed plasticity, and continuum elements). Model evaluation indicated that the most viable option to achieve accuracy and efficiency was the use of beam–column line elements with fiber-type cross-section models at the integration points. Initially, both displacement-based and force-based element formulations were evaluated; however, the displacement-based formulation resulted in an inaccurate representation of the axial force distribution along the length of the element. Therefore, only the force-based formulation was chosen for further study. The basic model included standard 1D constitutive models for confined concrete, plain concrete and reinforcing steel. Comparing simulated and measured response data showed that the concrete and steel material models must be regularized using a mesh-dependent characteristic length and a material-dependent post-yield energy to enable accurate, mesh-objective simulation of strength loss due to compression failure. The post-yield energy values were determined using relevant experimental data, an important but missing component of prior research on material regularization. The results of this study show that use of the regularized constitutive models significantly improved the accuracy of response predictions.
Computer vision-based inspection methods show promise for automating post-earthquake building inspections. These methods survey a building with unmanned aerial vehicles and automatically detect ...damage in the collected images. Nevertheless, assessing the damage’s impact on structural safety requires localizing damage to specific building components with known design and function. This paper proposes a BIM-based automated inspection framework to provide context for visual surveys. A deep learning-based semantic segmentation algorithm is trained to automatically identify damage in images. The BIM automatically associates any identified damage with specific building components. Then, components are classified into damage states consistent with component fragility models for integration with a structural analysis. To demonstrate the framework, methods are developed to photorealistically simulate severe structural damage in a synthetic computer graphics environment. A graphics model of a real building in Urbana, Illinois, is generated to test the framework; the model is integrated with a structural analysis to apply earthquake damage in a physically realistic manner. A simulated UAV survey is flown of the graphics model and the framework is applied. The method achieves high accuracy in assigning damage states to visible structural components. This assignment enables integration with a performance-based earthquake assessment to classify building safety.
Probabilistic seismic hazard analysis (PSHA) is generally recognized as the rational method to quantify the seismic threat. Classical formulation of PSHA goes back to the second half of the twentieth ...century, but its implementation can still be demanding for engineers dealing with practical applications. Moreover, in the last years, a number of developments of PSHA have been introduced; e.g., vector-valued and advanced ground motion intensity measure (IM) hazard, the inclusion of the effect of aftershocks in single-site hazard assessment, and multi-site analysis requiring the characterization of random fields of cross-correlated IMs. Although software to carry out PSHA has been available since quite some time, generally, it does not feature a user-friendly interface and does not embed most of the recent methodologies relevant from the earthquake engineering perspective. These are the main motivations behind the development of the practice-oriented software presented herein, namely REgionAl, Single-SitE and Scenario-based Seismic hazard analysis (REASSESS V2.0). In the paper, the seismic hazard assessments REASSESS enables are discussed, along with the implemented algorithms and the models/databases embedded in this version of the software. Illustrative applications exploit the potential of the tool, which is available at
http://wpage.unina.it/iuniervo/doc_en/REASSESS.htm
.
•The relative capabilities knowledge-based, machine learning-based, and mechanistic surrogate models are compared to estimate the life-cycle seismic loss of concrete frame buildings based on their ...geometry and design parameters.•Two scenarios of incomplete (early design) and complete (design development) design information are considered to evaluate the impact of design data availability on surrogate models’ prediction.•A sequential framework is proposed to implement surrogate models with lower fidelity in earlier stages of design exploration, where each prior model guide parametrization of the posterior model.•Data-driven models are a versatile tool to demarcate seismic loss under incomplete design data. Mechanistic surrogate models can better extract the relationship between design parameters and seismic loss as the scale of analysis shrinks.
A performance-based early design must assess the life cycle performance of a sizable design space at low computational cost and limited data. This paper evaluates the relative capabilities of three surrogate modeling approaches to estimate seismic loss under complete and incomplete design information scenarios. Three surrogate models of knowledge-based (i.e., from prior published assessments), data-driven (i.e., support vector machine trained on a simulation-based building inventory), and physics-based (i.e., equivalent single-degree-of-freedom systems) are systematically used to estimate bounds on direct seismic loss for four hypothetical concrete office construction projects in Charleston, South Carolina. Subsequently, a framework is presented that implements these surrogate models as a sequence to explore design alternatives consistent with divergence-convergence cycles of early design exploration. The results show that all different surrogate models provide reasonable accuracy for the complete design information case, whereas data-driven models provided higher accuracy than the other models. For incomplete design information, the data-driven models demarcated the performance space and estimated the same median loss values as detailed loss analysis. In contrast, physics-based surrogate models were more accurate in capturing the relationship between loss and design parameters for smaller sets of design alternatives. Nevertheless, all different surrogate modeling techniques were inadequate to capture loss variability between different designs of the same geometry.
