Buildings

24 pages, 5167 KiB

Open AccessArticle

Damage Identification Method and Uncertainty Analysis of Beam Structures Based on SVM and Swarm Intelligence Algorithm

by Zhixiang Hu, Huiyu Zhu, Lei Huang and Cheng Cheng

Buildings 2022, 12(11), 1950; https://doi.org/10.3390/buildings12111950 - 11 Nov 2022

Viewed by 1029

A two-stage damage identification method for beam structures based on support vector machine and swarm intelligence optimization algorithms is proposed. First, the frequencies and mode shapes of the beam structure are obtained using the smooth orthogonal decomposition method, and the normalized modal curvature [...] Read more.

A two-stage damage identification method for beam structures based on support vector machine and swarm intelligence optimization algorithms is proposed. First, the frequencies and mode shapes of the beam structure are obtained using the smooth orthogonal decomposition method, and the normalized modal curvature is calculated as the input of a pre-trained support vector machine to determine the damage location. Then, the stiffness loss at the damaged location of the structure is calculated using swarm intelligence algorithms. The fitness function is the sum of the residual squares of the frequencies of the damaged structure identified by the smooth orthogonal decomposition method and the frequencies calculated for each iteration of the intelligent optimization algorithm. Numerical examples of a damaged simply supported beam structure are used to verify the damage identification performance of the two-stage method. The accuracy of the support vector machine model under different damage degrees and noise levels is studied using the Monte-Carlo method, and an uncertainty of the damage degree prediction value is studied by comparing the particle swarm optimization algorithm, moth-fire algorithm, and mayfly algorithm. Full article

(This article belongs to the Special Issue Uncertainty Propagation of Complex Engineering Structures/Systems)

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Graphical abstract

24 pages, 2537 KiB

Open AccessArticle

Framework for Designing Virtual Water and Power Supply Networks with Interdependent Characteristics for Resilience Assessment

by Huiquan Miao, Siyuan Gao and Ding Wang

Buildings 2022, 12(10), 1670; https://doi.org/10.3390/buildings12101670 - 12 Oct 2022

Cited by 1 | Viewed by 1392

Abstract

Urban water and power supply networks with interdependent characteristics are essential components of urban infrastructures and play an important role in maintaining the daily operations and post-disaster recovery of cities. The aim of this study is to provide a method for researchers of [...] Read more.

Urban water and power supply networks with interdependent characteristics are essential components of urban infrastructures and play an important role in maintaining the daily operations and post-disaster recovery of cities. The aim of this study is to provide a method for researchers of resilient cities to build virtual water and power supply networks according to their basic physical mechanisms so that they can complete the risk or resilience evaluation of benchmark cities when some confidential infrastructure information is difficult to obtain. The innovation is that a new design framework for urban virtual water and power networks with interdependent characteristics combined with geographic information is suggested based on the perspective of practical engineering. After giving an overview of the framework, this paper presents the planning and design of the water and power supply networks as well as the interdependence between them in detail. Then the water and power supply networks of a virtual city called Virtual Shangcheng City are established, which verify the feasibility and practicality of the approach. This framework can establish virtual water and power supply networks with interdependent characteristics that conform to actual engineering and urban geographic information characteristics. Moreover, it can provide an effective modeling method for water and power supply networks in the absence of data for urban resilience and disaster risk studies. Full article

(This article belongs to the Special Issue Uncertainty Propagation of Complex Engineering Structures/Systems)

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20 pages, 4352 KiB

Open AccessArticle

Stochastic Optimization of Dissipation Structures Based on Lyapunov Differential Equations and the Full Stress Design Method

by Yunlong Zhang, Weizhi Xu, Dongsheng Du and Shuguang Wang

Buildings 2023, 13(3), 665; https://doi.org/10.3390/buildings13030665 - 02 Mar 2023

Cited by 1 | Viewed by 911

Abstract

This article presents a Lyapunov precise integral-based analysis method for seismic structures with added viscous fluid dampers. This study uses the full stress algorithm as the optimization method, considering the mean square of interstory drifts as the optimization objective, the position of the [...] Read more.

This article presents a Lyapunov precise integral-based analysis method for seismic structures with added viscous fluid dampers. This study uses the full stress algorithm as the optimization method, considering the mean square of interstory drifts as the optimization objective, the position of the damper as the optimization object, and the random vibration analysis method as the calculation method to optimize seismic frame structures with viscous dampers. A precise integral solution is derived for the Lyapunov equation based on the general expression of the Lyapunov differential equation for the damping system under the excitation of a nonstationary stochastic process using two types of modulation functions:

g (t) = 1

and

g (t) = \sqrt{t}

. Finally, the optimal damping arrangement is achieved using this method with a six-layer non-eccentric planar frame. In addition, the optimization results of this study are verified with those in the literature using time-history analysis, which verifies the feasibility and effectiveness of the proposed method. This study provides a method for the optimal configuration of dampers for seismic response of structures, which is beneficial for engineering applications and the protection of seismic structures. Full article

(This article belongs to the Special Issue Uncertainty Propagation of Complex Engineering Structures/Systems)

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13 pages, 3728 KiB

Open AccessArticle

Probabilistic Modeling for Cementitious Materials Based on Data of Nanoindentation

by Hankun Liu, Xiaodan Ren, Jie Li, Linglong Luo and Hongbing Li

Buildings 2023, 13(2), 416; https://doi.org/10.3390/buildings13020416 - 02 Feb 2023

Viewed by 900

Abstract

By introducing probabilistic modeling approaches, the interface transition zone (ITZ) and the bulk paste (BP) of concrete are investigated on the basis of the nanoindentation results, especially with respect to the relationship between the microstructure and mechanical properties of cementitious materials. The investigation [...] Read more.

By introducing probabilistic modeling approaches, the interface transition zone (ITZ) and the bulk paste (BP) of concrete are investigated on the basis of the nanoindentation results, especially with respect to the relationship between the microstructure and mechanical properties of cementitious materials. The investigation of the probability density function (PDF) of the random field for nanoindentation properties revealed that the same properties of the ITZ and the BP usually yield the same PDF, which was elaborated from different points of view. Specifically, a log-normal distribution was best for nanoindentation hardness, whereas the Weibull distribution and gamma distribution were much more suitable for the nanoindentation modulus of both the ITZ and the BP. According to the comparative study of the correlation structure, both the ITZ and BP obeyed the exponential correlation structure associated with a first-order autoregressive process, and basically exhibited a similar scale of fluctuation. Furthermore, the scales of fluctuation were found to be directly related to the clinker size and the distance between clinkers. Our work provides a new approach to stochastically modeling cementitious materials, where the content of hydration products controls the mean values of nano-properties, the indentation property dominates the PDF, and the nano-topological structure governs the correlation structure. Full article

(This article belongs to the Special Issue Uncertainty Propagation of Complex Engineering Structures/Systems)

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19 pages, 4478 KiB

Open AccessArticle

A Modified Compression Field Theory Based Analytical Model of RC Slab-Column Joint without Punching Shear Reinforcement

by Linfeng Wu, Tiancan Huang, Yili Tong and Shixue Liang

Buildings 2022, 12(2), 226; https://doi.org/10.3390/buildings12020226 - 17 Feb 2022

Cited by 8 | Viewed by 3410

Abstract

RC slab–column structures are widely used because of the advantages of small space occupation for horizontal members, easy construction and good economy. However, slab–column joints are prone to punching shear failures, which deteriorates structural safety. This paper provides an analytical model to predict [...] Read more.

RC slab–column structures are widely used because of the advantages of small space occupation for horizontal members, easy construction and good economy. However, slab–column joints are prone to punching shear failures, which deteriorates structural safety. This paper provides an analytical model to predict the punching shear capacity of the RC slab–column joint. A database of 251 test results is established for the shear punching capacity of slab–column joints without punching shear reinforcement. The performance of existing design codes in predicting the shear resistance of slab–column joints is investigated and compared based on the database. Then, based on the modified compression field theory (MCFT) model, an equation for calculating the punching shear resistance of slab–column joints without punching shear reinforcement is established. The prediction results of the analytical model are enhanced by using the regression analysis method. The model proposed in this paper is based on both reliable theoretical and the summary of a large number of test results, which has higher prediction accuracy than the design codes. Full article

(This article belongs to the Special Issue Uncertainty Propagation of Complex Engineering Structures/Systems)

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17 pages, 8001 KiB

Open AccessArticle

Effect of Spatial Variation of Earthquake Ground Motions on Seismic Vulnerability of Urban Road Network Considering Building Environment

by Ding Wang, Xinyu Zhao and Yue Liu

Buildings 2022, 12(3), 308; https://doi.org/10.3390/buildings12030308 - 05 Mar 2022

Cited by 2 | Viewed by 1554

Abstract

Evaluating the seismic damage of urban road infrastructure systems is of vital importance in reducing the earthquake hazard risk of cities. Urban road infrastructure systems are commonly represented as a spatial network that covers the whole city, and in its seismic damage analysis [...] Read more.

Evaluating the seismic damage of urban road infrastructure systems is of vital importance in reducing the earthquake hazard risk of cities. Urban road infrastructure systems are commonly represented as a spatial network that covers the whole city, and in its seismic damage analysis the spatial variation of earthquake ground motions cannot be ignored. However, the effect of the spatial variation of ground motions on the seismic vulnerability of urban road networks is unknown. In this article, based on the case study on Datong, China, it is shown that the spatially variation of ground motions may increase the damage risk of urban road networks and should be considered in the seismic vulnerability analysis. This was achieved by developing a method to evaluate the performance of a post-earthquake road network considering the structural damage of road components and the building environment. This work is anticipated to be a starting point for more sophisticated studies on the earthquake risk analysis of spatially extended urban lifeline systems. Full article

(This article belongs to the Special Issue Uncertainty Propagation of Complex Engineering Structures/Systems)

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25 pages, 8637 KiB

Open AccessArticle

Stochastic Semi-Physical Model for Nonstationary Spatially Variable Ground Motions in an Engineering Site

by Huiquan Miao, Yanqiong Ding and Jiaxu Shen

Buildings 2022, 12(10), 1727; https://doi.org/10.3390/buildings12101727 - 18 Oct 2022

Cited by 2 | Viewed by 1195

Abstract

Spatially variable ground motions are crucial for the seismic analysis and design of extended and multi-support structures. In this study, a new random nonstationary spatially variable ground motion model based on the propagation process of seismic waves is proposed. In particular, the amplitude [...] Read more.

Spatially variable ground motions are crucial for the seismic analysis and design of extended and multi-support structures. In this study, a new random nonstationary spatially variable ground motion model based on the propagation process of seismic waves is proposed. In particular, the amplitude and phase transfer functions of seismic waves at the local site are studied herein. The probability density function of the corresponding parameters is given. Two simple examples are used to show the generation of random ground motions. Compared with traditional methods, our proposed model not only has a clear physical background but also shows good practicability. The model should be for those researchers who want to use nonstationary spatially variable ground motions to study the seismic response of lifeline systems or building portfolios. Full article

(This article belongs to the Special Issue Uncertainty Propagation of Complex Engineering Structures/Systems)

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19 pages, 7554 KiB

Open AccessArticle

A Seismic Checking Method of Engineering Structures Based on the Stochastic Semi-Physical Model of Seismic Ground Motions

by Yanqiong Ding, Yazhou Xu and Huiquan Miao

Buildings 2022, 12(4), 488; https://doi.org/10.3390/buildings12040488 - 14 Apr 2022

Viewed by 1876

Abstract

A seismic checking method of engineering structures based on the stochastic semi-physical model of seismic ground motions is developed. Four groups of stochastic ground motions are generated using the stochastic semi-physical model of seismic ground motions. In conjunction with the probability density evolution [...] Read more.

A seismic checking method of engineering structures based on the stochastic semi-physical model of seismic ground motions is developed. Four groups of stochastic ground motions are generated using the stochastic semi-physical model of seismic ground motions. In conjunction with the probability density evolution method (PDEM) and the idea of the equivalent extreme-value event, the dynamic reliabilities of an engineering structure are evaluated. The dynamic reliability of the structure is taken as an index for seismic checking. A five-story reinforced concrete frame structure is analyzed using both the response spectrum method and the proposed method. Some features of the instantaneous probability density function (PDF) and its evolution, the extreme value distribution, and the dynamic reliability are discussed and compared with the results of the response spectrum method in the Chinese seismic code. The seismic checking results of the response spectrum method show that the structure is safe, while the results of the proposed method reveal a failure probability as high as 35.39%. Moreover, the structure has such different reliabilities when it is excited by different groups of simulated seismic ground motions. It reveals that a structure designed according to the seismic code may carry a high risk of failure. The proposed method provides a more accurate way for the evaluation of the reliabilities of engineering structures. Full article

(This article belongs to the Special Issue Uncertainty Propagation of Complex Engineering Structures/Systems)

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12 pages, 3193 KiB

Open AccessArticle

Uncertainty Analysis of Inverse Problem of Resistivity Model in Internal Defects Detection of Buildings

by Shan Xu, Xinran Wang, Ruiguang Zhu and Ding Wang

Buildings 2022, 12(5), 622; https://doi.org/10.3390/buildings12050622 - 07 May 2022

Cited by 3 | Viewed by 1383

Abstract

Fissure detection in ancient buildings is of vital importance in the evaluation of resistance or remediation in urban areas. Electrical resistivity imaging is an efficient tool to detect fissures or moisture erosion in buildings by highlighting the resistivity contrasts in the inversion models. [...] Read more.

Fissure detection in ancient buildings is of vital importance in the evaluation of resistance or remediation in urban areas. Electrical resistivity imaging is an efficient tool to detect fissures or moisture erosion in buildings by highlighting the resistivity contrasts in the inversion models. The traditional results of ERT images give deterministic interpretations of the internal artifact. However, the existence of equivalent models may correspond to different physical realities in engineering cases, to which the traditional ERT model cannot respond. In this paper, through the application of a field test on an ancient wall, it is shown that the segmentation of the equivalent model family is applicable to solve the internal defects detection problem in a probabilistic approach. It is achieved by performing a probabilistic approach to apply the uncertainty analysis. The procedure begins with the reduction in dimensions of the model by spectral decomposition, and the uncertainty space is rebuilt via Particle Swarm Optimization (PSO). By computing the uncertainty space, probabilistic maps are created to demonstrate the electrical anomaly in a simpler structure. The proposed method provides a more accurate approach for the internal defects detection of buildings by considering the possibilities hidden in the equivalent model family of ERT results. Full article

(This article belongs to the Special Issue Uncertainty Propagation of Complex Engineering Structures/Systems)

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