Buildings

29 pages, 10322 KiB

Open AccessArticle

Numerical and Statistical Evaluation of the Performance of Carbon Fiber-Reinforced Polymers as Tunnel Lining Reinforcement during Subway Operation

by Ishola Valere Loic Chango and Jun Chen

Buildings 2022, 12(11), 1913; https://doi.org/10.3390/buildings12111913 - 7 Nov 2022

Cited by 3 | Viewed by 1692

Abstract

Ground vibrations during train operations have become a serious problem in recent years. Local residents often feel disturbed by the vibrations emanating from the railroad line. This inconvenience is particularly pronounced in loose areas traversed by subways. However, improving the mechanical properties of [...] Read more.

Ground vibrations during train operations have become a serious problem in recent years. Local residents often feel disturbed by the vibrations emanating from the railroad line. This inconvenience is particularly pronounced in loose areas traversed by subways. However, improving the mechanical properties of tunnels has been the subject of several studies. Among these works, the widely discussed fiber-reinforced polymer (FRP) is considered as a material that can be incorporated into the tunnel structure to increase stiffness, durability, and corrosion resistance. However, the function of FRP in the interaction between the soil and the tunnel during operation has scarcely been studied. In this study, the effectiveness of carbon fiber-reinforced polymers (CFRP) as reinforcement of tunnel lining on ground vibration is investigated. For this purpose, a nonlinear 3D finite element model was developed based on a subway section in Shanghai to simulate the dynamic behavior of the system. The moving subway load was modeled as a transient dynamic load via a DLOAD subroutine, in which the rail irregularities are taken into account. The numerical model was efficiently validated by field tests. Then, the efficiency of using CFRP as concrete reinforcement of the tunnel lining during the subway operation was investigated. In addition, a statistical analysis of the ground dynamic response depending on the CFRP bars properties is presented, evaluated, and discussed. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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17 pages, 12690 KiB

Open AccessArticle

Finite Element Model for Vibration Serviceability Evaluation of a Suspended Floor with and without Tuned Mass Dampers

by Zhihao Wang, Luyao Song, Zhipeng Cheng, Hui Yang, Jinlong Wen and Meng Qi

Buildings 2023, 13(2), 309; https://doi.org/10.3390/buildings13020309 - 20 Jan 2023

Cited by 6 | Viewed by 2009

Abstract

This study aims to provide an accurate finite element (FE) modeling method for structural vibration serviceability evaluation of the suspended floor under human-induced excitation. The fundamental dynamic characteristics and human-induced vibration responses of a typical suspended floor were first measured via a series [...] Read more.

This study aims to provide an accurate finite element (FE) modeling method for structural vibration serviceability evaluation of the suspended floor under human-induced excitation. The fundamental dynamic characteristics and human-induced vibration responses of a typical suspended floor were first measured via a series of field tests. Subsequently, the overall and local equivalent FE models of the suspended floor were respectively established, and their applicability was then verified by comparing the predicted dynamic characteristics and responses of the suspended floor with the corresponding field test results. Finally, passive tuned mass dampers (TMDs) were designed for vibration control of the suspended floor using the local equivalent FE model, and the applicability of the local FE model in assessing the vibration serviceability of the suspended floor with TMDs was further confirmed via pedestrian-induced vibration tests. Results demonstrate that the simplified local equivalent FE model proposed in this study can well replace the complicated overall FE model to evaluate the vibration serviceability of the suspended floor with and without TMDs. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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18 pages, 10814 KiB

Open AccessArticle

Train-Induced Vibration Predictions Based on Data-Driven Cascaded State-Space Model

by Ziyu Tao, Zihao Hu, Ganming Wu, Conghui Huang, Chao Zou and Zhiyun Ying

Buildings 2022, 12(2), 114; https://doi.org/10.3390/buildings12020114 - 25 Jan 2022

Cited by 13 | Viewed by 3650

Abstract

Over-track buildings above metro depots have become common in megacities due to urban land shortages. The transmission of vibrations into the over-track buildings during routine train operations has the potential to adversely impact the occupants in terms of perceptible vibration and noise. There [...] Read more.

Over-track buildings above metro depots have become common in megacities due to urban land shortages. The transmission of vibrations into the over-track buildings during routine train operations has the potential to adversely impact the occupants in terms of perceptible vibration and noise. There is a need to quantify the potential impacts before construction for planning and design purposes. Train-induced vibration measurements were carried out on a six-story over-track building at the Luogang metro depot in Guangzhou, China, which is located adjacent to the tracks. The measurements were used to develop a data-driven cascaded state-space model, which can be applied to planned over-track buildings located in track areas to predict and assess whether train-induced vibrations would adversely affect the buildings’ future occupants. Vibration levels in the platform of the building’s columns were used as inputs to the models, thereby avoiding the complexity of modeling the transfer behavior of the platform. The predicted vibration levels corresponded with measurements in the existing building. This comparison validated the use of the model for future residential buildings where the predictions indicate that the impacts on its occupants will be within the applicable criteria. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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17 pages, 3329 KiB

Open AccessArticle

Equivalent Dynamic Load Factor of Different Non-Exceedance Probability for Crowd Jumping Loads

by Jiecheng Xiong, Shuqian Duan, Hui Qian and Ziye Pan

Buildings 2022, 12(4), 450; https://doi.org/10.3390/buildings12040450 - 6 Apr 2022

Cited by 5 | Viewed by 3822

Abstract

Existing dynamic load factors (DLF) for crowd jumping loads are modeled by identifying the peaks and energies from the corresponding Fourier amplitude spectrum, which may underestimate and overestimate structural responses, respectively. Based on the principle of equal structural responses, this study herein develops [...] Read more.

Existing dynamic load factors (DLF) for crowd jumping loads are modeled by identifying the peaks and energies from the corresponding Fourier amplitude spectrum, which may underestimate and overestimate structural responses, respectively. Based on the principle of equal structural responses, this study herein develops an equivalent DLF, using the frequency response function to weight and integrate the power spectral density (PSD) matrix of crowd jumping loads. Firstly, massive PSD matrices of different crowd sizes and different metronome frequencies are simulated using a random field model of crowd jumping loads. Thereafter, the equivalent DLF of different structural damping ratios, crowd sizes, metronome frequencies, and non-exceedance probabilities are investigated, and a model of the equivalent DLF is established accordingly. It is believed that this model could provide an efficient and accurate way to conduct reliability design for structures subjected to crowd jumping loads. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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18 pages, 4362 KiB

Open AccessArticle

Dynamic Reliability Analysis of Large-Span Structures under Crowd Bouncing Excitation

by Dongjun Zeng, Haoqi Wang and Jun Chen

Buildings 2022, 12(3), 332; https://doi.org/10.3390/buildings12030332 - 10 Mar 2022

Cited by 7 | Viewed by 2158

Abstract

Bouncing is one of the most common human crowd activities on civil infrastructures such as sports stadiums and concert halls, where the audience tends to make their bodies jump up and down to celebrate or participate in sport and musical events. Dynamic loads [...] Read more.

Bouncing is one of the most common human crowd activities on civil infrastructures such as sports stadiums and concert halls, where the audience tends to make their bodies jump up and down to celebrate or participate in sport and musical events. Dynamic loads are thus generated and exerted on the structures, giving unpleasant structural vibration, which may affect the functionality of the structure or even lead to a panic of the crowd. Although researchers have studied human-induced vibration from many perspectives including load models, calculation methods, criteria for serviceability evaluation, etc., there has been minimal work regarding crowd-induced reliability analysis, mainly because the stochastic feature of the crowd load as well as the mechanism describing the crowd–structure interaction is still not clear. In this paper, a framework to calculate crowd-induced structural vibration that considers the crowd–structure interaction effect is proposed and is validated through an experimental test. The dynamic parameters of the bouncing person in the crowd are adopted from a previous statistical study. The feasibility of a probability density evolution method (PDEM) is proved to be effective to calculate structural stochastic vibration under the bouncing crowd. The dynamic reliability of the structure is thus analyzed based on the stochastic responses. Results show that the consideration of the crowd–structure interaction effect significantly affects the dynamic reliability, which is also dependent on various factors including bouncing frequency, failure criteria, limit threshold, human model parameter distribution, etc. This paper provides a foundation for the performance-based vibration serviceability design of large-span structures. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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19 pages, 4709 KiB

Open AccessArticle

Evaluation of Inverted-Pendulum-with-Rigid-Legs Walking Locomotion Models for Civil Engineering Applications

by Stana Živanović, Bintian Lin, Hiep Vu Dang, Sigong Zhang, Mladen Ćosić, Colin Caprani and Qingwen Zhang

Buildings 2022, 12(8), 1216; https://doi.org/10.3390/buildings12081216 - 11 Aug 2022

Cited by 5 | Viewed by 2534

Abstract

Bipedal models for walkers, originally developed in the research field of biomechanics, have been identified as potential candidates for modelling pedestrians in structural engineering applications. These models provide insight into both the kinetics and kinematics of walking locomotion and are considered to have [...] Read more.

Bipedal models for walkers, originally developed in the research field of biomechanics, have been identified as potential candidates for modelling pedestrians in structural engineering applications. These models provide insight into both the kinetics and kinematics of walking locomotion and are considered to have a significant potential to improve the vibration serviceability assessment of civil engineering structures. Despite this notion, the ability of the bipedal models to represent the key features of the walking gait and natural variability within the pedestrian population are still under-researched. This paper critically evaluates the performance of two bipedal models with rigid legs to realistically both reproduce key features of an individual pedestrian’s walking gait and represent a wide range of individuals. The evaluation is performed for walking on a rigid, rather than vibrating, structure due to the availability of experimental data and expectation that successful modelling on rigid surfaces is a necessary condition for progressing towards modelling on the vibrating structures. Ready-to-use equations are provided and the ability of the models to represent the kinematics and kinetics of individual pedestrians as well as the inter-subject variability typical of the human population is critically evaluated. It was found that the two models could generate realistic combinations of the gait parameters and their correlations, but are less successful in reproducing genuine kinetic and kinematics profiles. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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21 pages, 7557 KiB

Open AccessArticle

Vibration Serviceability Assessment of a Historic Suspension Footbridge

by Elyas Bayat, Angelo Milone, Federica Tubino and Fiammetta Venuti

Buildings 2022, 12(6), 732; https://doi.org/10.3390/buildings12060732 - 28 May 2022

Cited by 2 | Viewed by 2032

Abstract

Experimental and numerical studies for the structural and vibration serviceability assessment of a historic suspension footbridge adopting non-invasive surveys and low-cost equipment are presented. Field surveys have been carried out to determine geometric properties, ambient vibration tests have been performed to estimate the [...] Read more.

Experimental and numerical studies for the structural and vibration serviceability assessment of a historic suspension footbridge adopting non-invasive surveys and low-cost equipment are presented. Field surveys have been carried out to determine geometric properties, ambient vibration tests have been performed to estimate the dynamic properties, and the dynamic response of the footbridge under the action of a single crossing pedestrian has been recorded. Based on field surveys, a 3D Finite Element model was built and was then calibrated against ambient vibration test results. The experimentally-measured maximum acceleration under the action of one crossing pedestrian is compared with the ones obtained numerically and analytically. Furthermore, vibration serviceability assessment under multi-pedestrian loading is carried out, adopting the simplified procedure recommended by a recent guideline. Results show that low-cost non-invasive dynamic testing is suitable to correctly identify the footbridge vertical natural frequencies and mode shapes, including higher-order ones, and to draw considerations about the state of degradation of the structure. Moreover, the level of vibration under the action of a single pedestrian can be estimated with sufficient accuracy using a simplified loading model, provided that the modal damping ratio is properly tuned. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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17 pages, 7828 KiB

Open AccessArticle

Maximal Multivariable Coefficient Analysis between Vibration Limits and Relevant Factors in General Buildings

by Lei Cao and Jun Chen

Buildings 2022, 12(6), 807; https://doi.org/10.3390/buildings12060807 - 11 Jun 2022

Viewed by 1436

Abstract

The vibration limit is an essential prerequisite for building vibration serviceability assessment, and various biological/environmental factors affect it deeply. Yet quantitative relationships between vibration limits and these factors in general buildings, such as the human weight, height and number of stories, stay unknown. [...] Read more.

The vibration limit is an essential prerequisite for building vibration serviceability assessment, and various biological/environmental factors affect it deeply. Yet quantitative relationships between vibration limits and these factors in general buildings, such as the human weight, height and number of stories, stay unknown. Based on data collected by an investigation conducted on a cell phone application, this paper proposed a novel approach for quantifying correlations between common relevant factors in general buildings and limits by maximal information coefficient (MIC). Vibration serviceability was thoroughly proved to be a multivariable system and crest factor/BMI had a higher correlation than other factors. A functional relationship and 95% confidence intervals between vibration limits and crest factor/BMI were proposed, respectively. Lilliefors test and normal probability plot show that residuals between fitted values of limits and measured ones follow a normal distribution. Finally, estimation of vibration serviceability based on probability was suggested when the crest factor/BMI and vibration magnitude were known. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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21 pages, 4182 KiB

Open AccessArticle

Sensitivity Analysis for Pedestrian-Induced Vibration in Footbridges

by Xiaojun Wei, Jingwei Zhang, Hao Zhou and Stana Živanović

Buildings 2022, 12(7), 883; https://doi.org/10.3390/buildings12070883 - 22 Jun 2022

Cited by 9 | Viewed by 2290

Abstract

This paper aims to provide a novel insight into the influence of uncertainties in system- and pedestrian-induced load parameters on the vibration response of footbridges. The study begins with a sensitivity analysis for the vertical vibration response of a representative footbridge to two [...] Read more.

This paper aims to provide a novel insight into the influence of uncertainties in system- and pedestrian-induced load parameters on the vibration response of footbridges. The study begins with a sensitivity analysis for the vertical vibration response of a representative footbridge to two loading cases: a single pedestrian and a crowd. Two methods are utilized: the Sobol’-based global sensitivity analysis method and the local sensitivity analysis method. Uncertainties in all model parameters (which include bridge and human body dynamics in a walking posture, as well as dynamic force generated by humans) are considered in stochastic response estimation. Parametric analysis is then performed to investigate the influence of the variation of the mean values of the bridge modal mass, damping ratio, and natural frequency on the results of global and local sensitivity analysis. Systematic comparison of the results of global and local sensitivity analysis is performed to identify their similarities and differences. It has been found that the sensitive parameters and their importance ranking strongly depend on bridge modal properties and loading scenarios (i.e., a single pedestrian or a crowd crossing). The damping ratio and natural frequency of the human body are found to be the only two insensitive parameters. Therefore, they could be treated as deterministic parameters in the stochastic estimation of human-induced vibration. Global sensitivity analysis is recommended as a choice for the sensitivity analysis of pedestrian-induced vibration of footbridges as it leads to more reliable results, owing to the advantage of characterizing model sensitivity over the entire input spaces. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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25 pages, 26299 KiB

Open AccessArticle

A Case Study on Structural Serviceability Subjected to Railway-Induced Vibrations at TOD Developed Metro Depot

by Yingying Liao, Peijie Zhang, Qiong Wu and Hougui Zhang

Buildings 2022, 12(8), 1070; https://doi.org/10.3390/buildings12081070 - 22 Jul 2022

Cited by 9 | Viewed by 2516

Abstract

As a sustainable mode of metro-development strategy, transit-oriented development (TOD) is rapidly growing to finance the transport infrastructure investment. The main negative consequence of constructing residential buildings directly over metro depots is railway-induced vibration, that may affect structural serviceability. The residents may feel [...] Read more.

As a sustainable mode of metro-development strategy, transit-oriented development (TOD) is rapidly growing to finance the transport infrastructure investment. The main negative consequence of constructing residential buildings directly over metro depots is railway-induced vibration, that may affect structural serviceability. The residents may feel uncomfortable, as the metro trains start running very early in the morning and finish daily operations very late at night. In order to evaluate the level of human comfort subject to the special situation, a case study was provided in this paper. Directed by the academic review, there were four common comfort evaluation methods, with difference indexes to describe the influence of vibrations. Therefore, a measurement campaign was conducted and both acceleration and velocity sensors were simultaneously installed at the same measurement points, to reduce the influence of the conversion accuracy. The results show that there are certain differences between the evaluation methods in assessing the vibration comfort, but considering the most adverse effects together, the over-track building at this particular TOD-developed depot can ensure that 90% of the occupants would not be highly annoyed by the vibrations. The main negative effect on human comfort at the TOD depot is that the high-level vibrations would cause interruptions in sleep. Among them, the vibrations in this case would affect the rest of 17% of the occupants in the bedrooms on the seventh floor, and make it difficult for 9% of the occupants to fall asleep. Therefore, the evaluation index was suggested to consider more factors related to sleep difficulties and awake threshold values. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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23 pages, 7105 KiB

Open AccessArticle

Human-Induced-Vibration Response Analysis and Comfort Evaluation Method of Large-Span Steel Vierendeel Sandwich Plate

by Lan Jiang, Ruoheng Cheng, Huagang Zhang and Kejian Ma

Buildings 2022, 12(8), 1228; https://doi.org/10.3390/buildings12081228 - 12 Aug 2022

Cited by 7 | Viewed by 1963

Abstract

A steel Vierendeel sandwich plate used as a large-span lightweight floor structure for vibration comfort during crowd gatherings was considered. Taking the steel Vierendeel sandwich plate in Guizhou Museum as an example, through finite element transient analysis, the effects of the structural damping, [...] Read more.

A steel Vierendeel sandwich plate used as a large-span lightweight floor structure for vibration comfort during crowd gatherings was considered. Taking the steel Vierendeel sandwich plate in Guizhou Museum as an example, through finite element transient analysis, the effects of the structural damping, pedestrian self-weight, floor span, surface concrete slab thickness, and structural parameters on the floor’s acceleration response distribution were deeply studied. According to the distribution characteristics of the acceleration response, a distribution model function was constructed, and a distribution Gauss model of the relationship between the peak acceleration response and the position of the steel Vierendeel sandwich plate was established. A field test of the sandwich plate under human-induced fixed-point excitation was carried out, and the model fitting results were compared with the actual test results. The results showed that the Gaussian model could effectively estimate the peak acceleration response at different positions on the floor. In addition, according to the distribution model, a comfort evaluation method based on the comfort assurance rate was proposed that could greatly reduce the representative value of the acceleration evaluation. The research results provide a reference for the comfort evaluation and corresponding vibration-reduction design of long-span steel Vierendeel sandwich plates. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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16 pages, 7978 KiB

Open AccessArticle

Experimental Study and Numerical Simulation Analysis on Vertical Vibration Performances of 12 m Span Wood Truss Joist Floors

by Zhanyi Zhang, Shuangyong Wang, Hao Deng and Haibin Zhou

Buildings 2022, 12(9), 1455; https://doi.org/10.3390/buildings12091455 - 15 Sep 2022

Cited by 1 | Viewed by 1700

Abstract

Walking-induced vibration control in wood floors is a critical issue attracting the attention of many researchers and engineers. This paper presents an experimental study applying static deflection tests, modal tests, and pedestrian load tests to a series of full-scale 12 m span tooth [...] Read more.

Walking-induced vibration control in wood floors is a critical issue attracting the attention of many researchers and engineers. This paper presents an experimental study applying static deflection tests, modal tests, and pedestrian load tests to a series of full-scale 12 m span tooth plates connected to wood truss joist floors with strongbacks and partition walls. A comparison of the calculation error of vibration parameters between the theoretical formula and a numerical model was also conducted. The results show that strongbacks and partition walls effectively reduce both the vertical displacement and the root means acceleration at the center of the floor under pedestrian load but increases the natural frequency. The partition wall can achieve a better vibration-reduction effect than strongbacks. The error of the finite element model is higher than that of the theoretical formula. Using the theoretical formula in engineering wood floor design is recommended. Full article

(This article belongs to the Special Issue Structural Vibration Serviceability and Human Comfort)

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