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18 pages, 3602 KiB

Open AccessArticle

Optimal Cable Force Adjustment for Long-Span Concrete-Filled Steel Tube Arch Bridges: Real-Time Correction and Reliable Results

by Mengsheng Yu, Xinyu Yao, Nianchun Deng, Tianzhi Hao, Longlin Wang and Hua Wang

Buildings 2023, 13(9), 2214; https://doi.org/10.3390/buildings13092214 - 30 Aug 2023

Cited by 1 | Viewed by 698

Abstract

For complex structures, the existing optimization method for suspender cable forces involves extensive matrix operations during the solution process, requiring high computational power and time. As a result, obtaining a more accurate solution becomes challenging. To address this issue and improve the stress [...] Read more.

For complex structures, the existing optimization method for suspender cable forces involves extensive matrix operations during the solution process, requiring high computational power and time. As a result, obtaining a more accurate solution becomes challenging. To address this issue and improve the stress distribution of suspenders in the completed state, while minimizing the need for frequent cable force adjustments and grid beam elevation changes during construction, a novel method for cable force optimization is proposed. In this study, the Pingnan Third Bridge, which is the world’s longest large span arch bridge with a span of 575 m, is taken as the engineering background. This study combines finite element analysis and multi-objective optimization methods to develop a cable force optimization approach for real-time correction during the panel girder lifting of long-span concrete-filled steel tube (CFST) arch bridges. The optimization method involves treating the panel girder weight and displacement during construction as parameter variables, and considering the displacement and unevenness of the panel girder in the completed state as constraint conditions. The objective equation is defined based on the displacement and cable force during the lifting construction process and, through optimization, the cable forces and displacements of each lifting section are calculated. The results demonstrate the feasibility of integrating optimization theory into the cable force optimization process during panel girder lifting. In this study, we have taken into account the characteristics of real-world engineering and focused on specific key points to reduce the order of the influence matrix. Consequently, the computational costs are reduced, facilitating the development of a multi-objective tension optimization program. By minimizing segment displacement variations and ensuring even cable force distribution in the completed state, the method ensures that the bridge meets the required completion requirements without the need for repetitive iterations or cumbersome calculations. It provides higher optimization efficiency and superior outcomes, offering significant value for cable force calculations during suspender construction of similar bridge types and guiding construction processes. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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19 pages, 4472 KiB

Open AccessArticle

Nonlinear Stress-Free-State Forward Analysis Method of Long-Span Cable-Stayed Bridges Constructed in Stages

by Shaoyang Wei, Wenfeng Gong, Xiaoguang Wu and Zhaohui Zhang

Buildings 2023, 13(7), 1735; https://doi.org/10.3390/buildings13071735 - 08 Jul 2023

Viewed by 785

Abstract

Structural analysis and construction control of staged-construction processes are major subjects in the context of modern long-span bridges. Although the forward and backward analysis methods are able to simulate situations, their main disadvantage is that they usually apply the stage superposition principle. In [...] Read more.

Structural analysis and construction control of staged-construction processes are major subjects in the context of modern long-span bridges. Although the forward and backward analysis methods are able to simulate situations, their main disadvantage is that they usually apply the stage superposition principle. In the actual construction process, due to changes made to the plan, the construction process needs to be adjusted at any time, and it is difficult to implement the construction process in complete accordance with the established plan. As a result, the existing simulation method based on the incremental structural analysis of each construction stage has poor adaptability to such adjustments. In this study, considering the strong geometric nonlinear behavior of the long-span cable-stayed bridge construction process, the geometrically nonlinear mechanical equations of the staged-construction bar system structure were derived. The minimum potential energy theorem was used by introducing the concept of the stress-free-state variable of the structural elements. The equation reflects the influence of the change in the stress-free-state variables of structural elements on the completion state of the structure. From the analysis of the geometrical condition that the equilibrium equation holds, the stress-free installation condition of the closing section of the planar beam element structure was obtained. A new simulation method for long-span cable-stayed bridge construction has been proposed, which is called the stress-free-state forward analysis. This method can directly obtain the intermediate process state of cable-stayed bridge construction without performing stage-by-stage demolition calculations, and causing the internal force and deformation of the completion state to reach the design target state. This method can realize the simulation of multi-process parallel operation in construction, and solves the problem of automatic filtering of temporary loads. To illustrate the application of the method, a long-span cable-stayed bridge was analyzed. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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14 pages, 3350 KiB

Open AccessArticle

Application of Bayesian Update Method in the Construction Control of Continuous Rigid Frame Bridge Girders with High Piers and Large Spans

by Xiaolong Zhou, Taoxin Deng, Li Chen, Jie Chen, Ao Li, Qijie Yuan, Wei Fang and Jianfeng Gu

Buildings 2023, 13(6), 1556; https://doi.org/10.3390/buildings13061556 - 19 Jun 2023

Cited by 2 | Viewed by 882

Abstract

In the construction process of large-scale bridges, there are uncertainties and time-varying factors in the environment and construction loads. It is difficult to make accurate estimates of the theoretical calculation models of construction control in advance. In view of this situation, Bayesian dynamic [...] Read more.

In the construction process of large-scale bridges, there are uncertainties and time-varying factors in the environment and construction loads. It is difficult to make accurate estimates of the theoretical calculation models of construction control in advance. In view of this situation, Bayesian dynamic updating method is introduced to re-estimate the predicted results of the theoretical model. When applying this method, first, the finite element calculation model is determined based on the response surface method, and its calculation results are used as prior information. Then, combined with the actual detection data during the construction process, the Bayesian update formula is derived based on the conjugate prior distribution to correct the theoretical prediction results of bridge construction monitoring. Finally, the actual stress detection data of the control section of high-pier and large-span continuous rigid frame bridges during the construction process illustrate the application process of Bayesian updating in improving the theoretical prediction model. Results indicate that the internal force of the bridge control section obtained by re-evaluating by Bayesian theory not only incorporates the priori information models but also actual monitors sample information during the construction process. The predicted results reflect the true deformation and stress state of the bridge during the bridge construction process and improve the precision of construction monitoring. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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16 pages, 6216 KiB

Open AccessArticle

Identification of Simulated Damage in Prestressed Anchorage Using Admittance-Based Active Sensing Technique

by Chi-Thien Nguyen, Thanh-Truong Nguyen, Trung-Hau Nguyen, Ba-Tung Le, Tran-De-Nhat Truong, Duc-Duy Ho and Thanh-Canh Huynh

Buildings 2023, 13(4), 1068; https://doi.org/10.3390/buildings13041068 - 18 Apr 2023

Cited by 1 | Viewed by 966

Abstract

This study examined the feasibility of the admittance-based method for detecting simulated damage in the bearing plate of a prestressed anchorage. The proposed method utilized the PZT (lead zirconate titanate) interface technique to acquire a strong admittance response from the anchorage. Firstly, the [...] Read more.

This study examined the feasibility of the admittance-based method for detecting simulated damage in the bearing plate of a prestressed anchorage. The proposed method utilized the PZT (lead zirconate titanate) interface technique to acquire a strong admittance response from the anchorage. Firstly, the numerical feasibility of the method was demonstrated by detecting the presence of fatigue cracks and preload changes in a fixed–fixed beam-like structure. Next, the experimental verification was carried out using a lab-scale prestressed anchorage model. A PZT interface prototype was designed and surface-mounted on the bearing plate. The admittance response of the PZT interface was measured before and after the simulated damage cases of the bearing plate. Afterwards, a statistical damage metric, root-mean-square deviation (RMSD) was used to quantify the change in the admittance spectrum and identify the damage’s presence. It was shown that the experimental admittance response was consistent with the numerical simulation result in the same effective frequency band. Both the numerical and experimental results showed clear shifts in the admittance spectrum due to structural damage. The simulated damages in the bearing plate were successfully identified by the RMSD evaluation metric. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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15 pages, 4510 KiB

Open AccessArticle

Detection and Damage Evaluation of Hinge Joints in Hollow Slab Bridges Based on a Light-Load Field Test

by Aiping Guo, Haiqing Zhu and Ajuan Jiang

Buildings 2023, 13(3), 699; https://doi.org/10.3390/buildings13030699 - 06 Mar 2023

Viewed by 1475

Abstract

The hollow slab bridge is a widely used bridge type for urban bridges. The slabs are prefabricated in a factory and are assembled on site, and then the hinge joints are poured on site. Shallow hinge joints have been used in most existing [...] Read more.

The hollow slab bridge is a widely used bridge type for urban bridges. The slabs are prefabricated in a factory and are assembled on site, and then the hinge joints are poured on site. Shallow hinge joints have been used in most existing hollow slab bridges, which commonly bring inadequate connection to the adjacent slabs and probably result in bridge damage. Traditional detection and test methods for hinge joints interrupt traffic, which is inconvenient for local commuters. In the present study, a light-load field test method for hinge joints was proposed. The principles and procedures of the light-load test were concluded and provided based on the test results of 96 spans. The theoretical and measured lateral load distribution ratios were calculated and compared based on hinge joint plate theory. The damage evaluation method and damage classification for hinge joints were defined based on the test results of 1100 hinge joints. Furthermore, the accuracy of the proposed method was verified by a destructive experiment. The research results indicate that the light-load field test and the damage evaluation method for hinge joints are indeed convenient, reliable, and economical, and deserve practical spread and repetition in this area. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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15 pages, 6353 KiB

Open AccessArticle

Stress Detection of Precast Pipe Piles Based on the Low-Loss Slotting Method

by Jinbao Li, Biqing Li, Degen Chen, Chang Wu and Hong Zhu

Buildings 2023, 13(3), 648; https://doi.org/10.3390/buildings13030648 - 28 Feb 2023

Viewed by 1044

Abstract

Tilting of buildings due to uneven settlement, construction quality issues or other problems is one of the critical accidents threatening the safety of buildings. In order to determine a reasonable solution with respect to the rectification of the tilting building, detection of the [...] Read more.

Tilting of buildings due to uneven settlement, construction quality issues or other problems is one of the critical accidents threatening the safety of buildings. In order to determine a reasonable solution with respect to the rectification of the tilting building, detection of the stresses of the substructure is necessary. In this study, a stress release method to test the stress of prefabricated pipe pile under loading is studied by combining experimental research and finite element numerical simulation. Based on various measurements, such as traditional strain gauges, vibrating wire strain gauges, and three-dimensional digital image correlation (DIC) tests, the relationship between local residual stress and actual stress of the slotted area at different load levels is determined. Meanwhile, the stress release process in slotted precast pipe pile was numerically simulated with ABAQUS to investigate the influence of the slotting dimension parameters on the stress release rate at different load levels. Based on 1042 sets of finite element modeling results of multi-parameter combination, the quantitative relationship between slot width, depth, spacing, prestress level and stress release rate is studied. An explicit prediction model of the stress release rate is given by regression analysis of combined test results and simulation data. With the prediction model, the stress condition of a loaded precast pipe pile can be accurately predicted based on low-loss slotting. Compared to the traditional stress release method, the proposed method has better controllability and applicability, less damage to the structure, and stronger anti-disturbance ability. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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21 pages, 5472 KiB

Open AccessArticle

Modelling Strategies for the Updating of Infilled RC Building FEMs Considering the Construction Phases

by Vanni Nicoletti and Fabrizio Gara

Buildings 2023, 13(3), 598; https://doi.org/10.3390/buildings13030598 - 24 Feb 2023

Cited by 3 | Viewed by 1157

Abstract

This paper deals with modelling strategies for the updating of Finite Element Models (FEMs) of infilled Reinforced Concrete (RC) frame buildings. As is known, this building typology is the most adopted worldwide for residential houses and strategic buildings, such as hospitals, schools, police [...] Read more.

This paper deals with modelling strategies for the updating of Finite Element Models (FEMs) of infilled Reinforced Concrete (RC) frame buildings. As is known, this building typology is the most adopted worldwide for residential houses and strategic buildings, such as hospitals, schools, police stations, etc. The importance of achieving trustworthy numerical models for these kinds of structures, especially the latter ones, is clear. The updating procedure mainly consists in changing the geometrical and mechanical material properties of models until pre-determined convergence criteria are verified, the latter based on the comparison between numerical and experimental outcomes. In this work, the modelling strategies that can be adopted to refine FEMs of infilled RC buildings are treated in-depth, starting from the simple model usually developed for design purposes. Modelling techniques relevant to the geometry, the mechanical properties, the mass, and the restraint conditions of the model are discussed. Moreover, the approaches that can be adopted to calibrate numerical models during the construction process are addressed as well. Then, an application of the proposed strategies is provided with reference to a real building that was investigated during its construction. The proposed modelling strategies proved to be effective in the model updating of the considered building and provide useful support for the calibration of FEMs of this building typology in general. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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14 pages, 4376 KiB

Open AccessArticle

Effect of Shear Deformation at Segmental Joints on the Short-Term Deflection of Large-Span Cantilever Cast Prestressed Concrete Box Girders

by Jie Liu, Xiangyu Huang, Juanjuan Chen and Qiaoyun Wu

Buildings 2023, 13(1), 219; https://doi.org/10.3390/buildings13010219 - 12 Jan 2023

Cited by 1 | Viewed by 1170

Abstract

The excessive deflection of large-span cantilever cast prestressed concrete (LCCPC) box girders has always been a complex problem to be solved in bridge engineering. To analyze the effect of shear deformation at segmental joints on the deflection of LCCPC box girders, comparison tests [...] Read more.

The excessive deflection of large-span cantilever cast prestressed concrete (LCCPC) box girders has always been a complex problem to be solved in bridge engineering. To analyze the effect of shear deformation at segmental joints on the deflection of LCCPC box girders, comparison tests were carried out on three prestressed concrete (PC) I-girders with joints and a PC I-girder without joints, and a finite element simulation method of segmental joints was proposed based on the tests. Subsequently, finite element analysis was conducted on a test girder and the Assistant Shipping Channel Bridge of Humen Bridge (a PC continuous rigid frame bridge with a main span of 270 m) using this method. The experimental and theoretical analysis results showed that the effect of the shear deformation at joints compared to the deformation at midspan of the girder specimens was negligible. Deformation at midspan of the specimens would not significantly increase, even if shear rigidity at the joints was significantly reduced or there were more joints in the girder specimen. The effect of shear deformation at segmental joints on the deflection of LCCPC box girders was quite small and thus insignificant. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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22 pages, 5649 KiB

Open AccessArticle

Structural Damage Identification Based on Convolutional Neural Networks and Improved Hunter–Prey Optimization Algorithm

by Chunyan Xiang, Jianfeng Gu, Jin Luo, Hao Qu, Chang Sun, Wenkun Jia and Feng Wang

Buildings 2022, 12(9), 1324; https://doi.org/10.3390/buildings12091324 - 29 Aug 2022

Cited by 9 | Viewed by 1584

Abstract

Accurate damage identification is of great significance to maintain timely and prevent structural failure. To accurately and quickly identify the structural damage, a novel two-stage approach based on convolutional neural networks (CNN) and an improved hunter–prey optimization algorithm (IHPO) is proposed. In the [...] Read more.

Accurate damage identification is of great significance to maintain timely and prevent structural failure. To accurately and quickly identify the structural damage, a novel two-stage approach based on convolutional neural networks (CNN) and an improved hunter–prey optimization algorithm (IHPO) is proposed. In the first stage, the cross-correlation-based damage localization index (CCBLI) is formulated using acceleration and is input into the CNN to locate structural damage. In the second stage, the IHPO algorithm is applied to optimize the objective function, and then the damage severity is quantified. A numerical model of the American Society of Civil Engineers (ASCE) benchmark frame structure and a test structure of a three-storey frame are adopted to verify the effectiveness of the proposed method. The results demonstrate that the proposed approach is effective in locating and quantifying structural damage precisely regardless of noise perturbations. In addition, the reliability of the proposed approach is evaluated using a comparison between it and approaches based on CNN or the IHPO algorithm alone. The comparison results indicate that in single and multiple damage events, the proposed two-stage damage identification approach outperforms the other two approaches on the accuracy, and the average consumption time is 20% less than the method using the IHPO algorithm alone. Therefore, this paper provides a guideline for the study of high-accuracy and quick damage identification using both data-based and model-based hybrid methods. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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24 pages, 6334 KiB

Open AccessArticle

Online Sifting Technique for Structural Health Monitoring Data Based on Recursive EMD Processing Framework

by Danhui Dan, Chenqi Wang, Ruiyang Pan and Yangmei Cao

Buildings 2022, 12(9), 1312; https://doi.org/10.3390/buildings12091312 - 26 Aug 2022

Cited by 3 | Viewed by 1397

Abstract

Real-time and online screening techniques for single load effect signal monitoring are one of the key issues in smart structure monitoring. In this paper, an online signal sifting framework called online recursive empirical mode decomposition (EMD) is proposed. The framework is based on [...] Read more.

Real-time and online screening techniques for single load effect signal monitoring are one of the key issues in smart structure monitoring. In this paper, an online signal sifting framework called online recursive empirical mode decomposition (EMD) is proposed. The framework is based on an improved EMD that optimizes the boundary effect by using extreme value recursion and eigensystem realization algorithm (ERA) extension, and combines the intrinsic mode functions (IMFs) correlation coefficient and adaptive filtering to select IMFs for signal reconstruction to achieve the sifting purpose. When applied to simulated signals, the method satisfies the requirements of signal sifting in an online environment with high adaptivity, low parameter sensitivity and good robustness. The method was applied to the dynamic strain data collected by the health monitoring system of Daishan Second Bridge to achieve real-time online sifting of strain signals caused by traffic loads, which provided the basis for subsequent data analysis applications and confirmed the value of the application in a real bridge health monitoring system. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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21 pages, 6003 KiB

Open AccessArticle

Research on the Application of Multi-Source Data Analysis for Bridge Safety Monitoring in the Reconstruction and Demolition Process

by Meizhen Fu, Yuxiong Liang, Qingsong Feng, Bitao Wu and Guoxi Tang

Buildings 2022, 12(8), 1195; https://doi.org/10.3390/buildings12081195 - 09 Aug 2022

Cited by 6 | Viewed by 1650

Abstract

With the increase of bridge-required demolition/dismantling for reconstruction or modification, the early warning of construction emergencies is greatly needed for monitoring the structural safety of bridges under construction. In this paper, based on the multi-source data of nearby construction and demolition construction of [...] Read more.

With the increase of bridge-required demolition/dismantling for reconstruction or modification, the early warning of construction emergencies is greatly needed for monitoring the structural safety of bridges under construction. In this paper, based on the multi-source data of nearby construction and demolition construction of a large-span RC arch bridge in China, the Analytic Hierarchy Process (AHP) method is adopted to analyze the multi-source data and set the early warning threshold for bridge safety in construction. According to the analytical results, a reasonable evaluation of AHP factors can improve the accuracy and timeliness of safety early warning in the structural safety monitoring of bridges during the construction process. The weight of the monitoring data in AHP should be assigned according to its reliability, stability, and importance. Bridge safety assessment of nearby construction having harmful vibration should prioritize dynamic bridge monitoring by cooperating with multi-source data, including stress, and deformation monitoring of the bridge is necessary. The assessment results proved that multi-source data, including but not limited to structural stress and deformation monitoring data, vibration data, theoretical prediction data, environment data such as temperature data, and construction/maintenance history data, are necessary for safety monitoring and early warning of construction with specifications related to bridge construction. The early warnings triggered by the evaluation results successfully ensure the safety status of the bridge during nearby construction and demolition construction, which shows the proposed method can provide a guideline for comprehensively evaluating and early warning of the status of bridge construction. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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17 pages, 12557 KiB

Open AccessArticle

Research on Soft Flutter of 420m-Span Pedestrian Suspension Bridge and Its Aerodynamic Measures

by Qinghai Guan, Lei Liu, Hui Gao, Yujing Wang and Jiawu Li

Buildings 2022, 12(8), 1173; https://doi.org/10.3390/buildings12081173 - 05 Aug 2022

Cited by 4 | Viewed by 1731

Abstract

In order to study the flutter of long-span pedestrian suspension bridge and its aerodynamic control, a 420m-span pedestrian suspension bridge is used as an engineering example, the wind-induced vibration of seven particular aerodynamic sections is studied by wind tunnel tests, and the soft [...] Read more.

In order to study the flutter of long-span pedestrian suspension bridge and its aerodynamic control, a 420m-span pedestrian suspension bridge is used as an engineering example, the wind-induced vibration of seven particular aerodynamic sections is studied by wind tunnel tests, and the soft flutter phenomenon of two kinds of aerodynamic sections is identified. The results show that the wind fairing and the wind-retaining plate measures are not necessarily effective measures to improve the wind-induced stability of long-span pedestrian suspension bridge, as these two measures may reduce the flutter stability: the wind fairing section in the positive angle of attack is prone to torsion-based soft flutter phenomenon, in which the vertical vibration spectrum contains multiple vibration frequencies, so the conventional formulation of the linearized self-excited forces is no longer satisfied; the wind-retaining plate section in the negative angle of attack is prone to soft flutter dominated by vertical vibration, and the beat vibration phenomenon is found in the torsional vibration time history of the wind-retaining section. Slotting in the center of the girder section can significantly change the flow state of the section, which is an effective measure to improve the flutter stability of the pedestrian suspension bridge. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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21 pages, 6906 KiB

Open AccessArticle

Research on Bridge Damage Identification Based on WPE-MDS and HTF-SAPSO

by Haoxuan Wu, Minshui Huang, Zihao Wan and Zian Xu

Buildings 2022, 12(8), 1089; https://doi.org/10.3390/buildings12081089 - 25 Jul 2022

Cited by 1 | Viewed by 1229

Abstract

In recent decades, structural damage identification based on the wavelet analysis method has been widely developed, but it is still confronted with many difficulties, such as large decomposition error and complex data. In order to overcome the shortcomings of analysis based on wavelet, [...] Read more.

In recent decades, structural damage identification based on the wavelet analysis method has been widely developed, but it is still confronted with many difficulties, such as large decomposition error and complex data. In order to overcome the shortcomings of analysis based on wavelet, the wavelet packet analysis method is adopted to decompose the acceleration data into wavelet packets, and the frequency band energy value after wavelet packet decomposition (WPE) is taken as the different dimensions of the Mahalanobis distance squared (MDS) in this study, where the MDS value of the same element between different samples is calculated, and the mean value of 30 groups of MDS values for each element is processed. The change rate between the MDS value of the element that exceeds the MDS value in the healthy state and the MDS mean value in the healthy state as the objective function. The combination of weight coefficient and hyperbolic tangent function is used to improve the simulated annealing particle swarm optimization (SAPSO) algorithm, and the improved hyperbolic tangent function-simulated annealing particle swarm optimization (HTF-SAPSO) is used to iteratively calculate the damage severity. The numerical simulation and vibration testing of a steel beam are conducted to verify the identification performance of damage location and the analysis of damage severity by this method, respectively. The numerical model of the experimental I-beam is established based on the MATLAB modeling platform, and the different damage cases are utilized to illustrate the correctness of this study. The different proportions of noise effects are adopted to the numerical simulation analysis, where the correlations between noise effects and MDS value and damage severity are analyzed. In the numerical simulation, although the MDS value increases to different degrees with the increase of the noise ratio, the damage identification result of the damaged element remains mostly constant, which indicates that the influence is negligible. In conclusion, it is feasible to construct the damage index via the combination of WPE and MDS values, the damage location can be judged from whether the MDS value of the element exceeds the threshold, and the HTF-SAPSO algorithm is more efficient and accurate to be adopted in the quantification of the damage severity. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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11 pages, 3200 KiB

Open AccessArticle

Prestressed Concrete Box Girder with High-Capacity Strands-Monitoring and Analysis during Fabrication

by Xin Jiang, Xinlin Ban, Lin Ma, Yonghua Su, Qi Cao, Zhouyu Zhang and Jichao Guo

Buildings 2022, 12(7), 911; https://doi.org/10.3390/buildings12070911 - 28 Jun 2022

Cited by 1 | Viewed by 2043

Abstract

Despite the attractive merits of high-capacity strands, the application in bridge girders is limited due to concerns, including concrete cracking, excessive stress, and cambers. An efficient and defect-free production is the first step to wide application. The objective of this research was to [...] Read more.

Despite the attractive merits of high-capacity strands, the application in bridge girders is limited due to concerns, including concrete cracking, excessive stress, and cambers. An efficient and defect-free production is the first step to wide application. The objective of this research was to alleviate the production concerns of prestressed concrete bridge girders using high-capacity strands. A gigantic prestressed concrete box girder using 18-mm strands was produced; its entire fabrication process (from strand stressing to detension) was introduced. Sixteen temperature gauges were embedded in the girder to monitor the hydration of the large volume of concrete and the adjacent environmental temperature. Moreover, displacement transducers were used to measure the camber at detension; load cells were installed to monitor the variations of the prestressing strand tensile forces during fabrication. Monitoring and analysis showed that the timing of the detension is determined by the hydration of the concrete, the compressive strength of the concrete, and its modulus of elasticity or age. Since the tensile forces in strands are affected by the concrete’s internal temperature, the detension is conducted after the concrete temperature falls back (close to its initial value); otherwise, unfavorable and considerable prestress losses are caused. Finally, a 4-d detension was suggested since the hydration was not a concern at the time; the predicted prestress loss and camber were acceptable and the concrete material properties at 4 d satisfied the requirements. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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14 pages, 7413 KiB

Open AccessArticle

Structural Performance and Reasonable Cross-Ratio of Cross-Cable Multi-Tower Cable-Stayed Bridges

by Sisi Yao, Biao Peng, Luyao Wang and Hengda Chen

Buildings 2022, 12(6), 764; https://doi.org/10.3390/buildings12060764 - 04 Jun 2022

Cited by 3 | Viewed by 1526

Abstract

The Queensferry Crossing in the UK is the first multi-tower cable-stayed bridge in the world to use mid-span cross-stayed cables to improve structural rigidity. To study the structural performance and economy of cross-cable multi-tower cable-stayed bridges, a total of 11 finite element models [...] Read more.

The Queensferry Crossing in the UK is the first multi-tower cable-stayed bridge in the world to use mid-span cross-stayed cables to improve structural rigidity. To study the structural performance and economy of cross-cable multi-tower cable-stayed bridges, a total of 11 finite element models were established using two cross-cable setting methods. By changing the number of crossed cables in the mid-span, the variation laws of structural deformation and internal force are obtained. The cross-cable efficiency based on structural stiffness and the cross-cable economy based on the consumption of cables used in the entire bridge are quantitatively analyzed, and it is considered that there is a reasonable cross-ratio of cross-cables. Combined with the current design specification and the empirical data of the actual bridge, the limits of the double indicators were determined, and a scheme comparison chart was formed. The results show that under the action of unbalanced load, the cross cable can greatly reduce deformation and balance the internal force of the structure. The optimal solution is to form a mid-span cable crossing by adjusting the cable spacing, and the reasonable range of cross-ratio is 15%~35%. If the structural stiffness is improved by adding additional cross cables, the cross-ratio should be controlled within 16% to ensure structural economy. This provides a reference for the design and research of cross-cable multi-tower cable-stayed bridges in the future. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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14 pages, 4341 KiB

Open AccessArticle

Analysis of Buckling Deformation for the Side Plate of Rectangular CSFT Column Based on Plate Theory with Bi-Axial Loads

by Bing Xu, Lang Wang, Chunyan Xiang and Zhenyu Han

Buildings 2022, 12(5), 626; https://doi.org/10.3390/buildings12050626 - 09 May 2022

Cited by 2 | Viewed by 1573

Abstract

In this paper, under the condition of bidirectional stress, the buckling deformation of the side plate in a rectangular concrete-filled steel tube (CFST) column has been studied in detail. We have conducted a theocratical analysis, an experimental validation and a finite element simulation [...] Read more.

In this paper, under the condition of bidirectional stress, the buckling deformation of the side plate in a rectangular concrete-filled steel tube (CFST) column has been studied in detail. We have conducted a theocratical analysis, an experimental validation and a finite element simulation to investigate the influences of the height-width ratios and Nominal Poisson’s ratios on the buckling form of the side plate, and we also try to explain the change of buckling form between unidirectional and bidirectional stress, both of them can provide a good reference and basis for design and application of the CFST column. The specific work can be summarized as follows: Firstly, a theoretical analysis has been conducted to study the buckling coefficient solution method of the thin plate under the conditions of axial compress and transverse tension. Then, under the conditions of the unidirectional and the bidirectional stress, a comparative study is carried out to investigate the changing relationship of the buckling coefficient (k) of the side plate; the results indicate that the buckling characteristic is changed due to the bidirectional stress, meanwhile, the buckling coefficient and the number of buckling half-wave will increase. Furthermore, the existing outcomes and the numerical simulations are adopted to study the relevance between the number of the elastic buckling half-wave in the side plate and the corresponding height-width ratio of the component; the results indicate that the former is larger than the latter. Finally, based on the obtained, the buckling relationship curve, the conclusion can be drawn as follows: when the bidirectional stress has been applied to the side plate, there is an equal interval between the different buckling half-waves; meanwhile, the interval shows a quadratic function reduce trend with the increase of nominal Poisson’s ratio. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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16 pages, 16667 KiB

Open AccessArticle

Improved Data-Driven Stochastic Subspace Identification with Autocorrelation Matrix Modal Order Estimation for Bridge Modal Parameter Extraction Using GB-SAR Data

by Xianglei Liu, Songxue Zhao, Peipei Wang, Runjie Wang and Ming Huang

Buildings 2022, 12(2), 253; https://doi.org/10.3390/buildings12020253 - 21 Feb 2022

Cited by 8 | Viewed by 1822

Abstract

With the advantage of non-contact measurement, ground-based synthetic aperture radar (GB-SAR) has been widely used to obtain the dynamic deflection of various bridges. Data-driven stochastic subspace recognition (Data-SSI), a popularized time-domain technique, is commonly used for modal parameter identification of bridges. To improve [...] Read more.

With the advantage of non-contact measurement, ground-based synthetic aperture radar (GB-SAR) has been widely used to obtain the dynamic deflection of various bridges. Data-driven stochastic subspace recognition (Data-SSI), a popularized time-domain technique, is commonly used for modal parameter identification of bridges. To improve the computational efficiency and accuracy of the Data-SSI method for bridge modal parameter estimation using GB-SAR, this paper proposes an improved Data-SSI method. First, boxplot data filtering is applied to screen out the error points to generate a Hankel matrix. Second, the Hankel matrix compression method is presented to reduce the ill-conditioned vectors in the column vectors of the Hankel matrix to improve calculation efficiency. Finally, the exact modal order (EMO) modal estimation algorithm based on the autocorrelation matrix is adopted to reduce the generation of false modes and improve the calculation efficiency. The results of simulation and field experiments show that the natural frequency values for the improved Data-SSI method are 2.3208 and 2.3189 and the damping ratio coefficient values are 8.10 and 8.08, under windows 1 and 2, respectively. The operation times using the improved Data-SSI method are 2.02 s and 7.61 s under windows 1 and 2, respectively. This proves that the proposed improved Data-SSI method has higher accuracy and computational efficiency. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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34 pages, 2990 KiB

Open AccessReview

The Current Development of Structural Health Monitoring for Bridges: A Review

by Zhihang Deng, Minshui Huang, Neng Wan and Jianwei Zhang

Buildings 2023, 13(6), 1360; https://doi.org/10.3390/buildings13061360 - 23 May 2023

Cited by 21 | Viewed by 5155

Abstract

The health monitoring system of a bridge is an important guarantee for the safe operation of the bridge and has always been a research hotspot in the field of civil engineering. This paper reviews the latest progressions in bridge health monitoring over the [...] Read more.

The health monitoring system of a bridge is an important guarantee for the safe operation of the bridge and has always been a research hotspot in the field of civil engineering. This paper reviews the latest progressions in bridge health monitoring over the past five years. This paper is organized according to the various links of the bridge health monitoring system. Firstly, the literature on monitoring technology is divided into two categories, sensor technology and computer vision technology, for review. Secondly, based on the obtained monitoring data, the data processing methods including preprocessing, noise reduction, and reconstruction are summarized. Then, the technical literature on abnormal data early warning systems is summarized. The recent advances in vibration-based and non-destructive testing-based damage identification methods are reviewed in the next section. Finally, the advantages and disadvantages of the existing research and the future research directions are summarized. This review aims to provide a clear framework and some reliable methods for future research. Full article

(This article belongs to the Special Issue Construction Process Monitoring and Structural Damage Identification for Buildings and Bridges)

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