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Evolution of suspension bridge structural systems,design theories,and shape-finding methods:A literature survey

Journal of Traffic and Transportation Engineering(English Edition) 2024年第2期11卷 225-244页

作者： Wenming Zhang Genmin Tian Yupeng Chen key laboratory of concrete and Pre-stressed concrete Structures of Ministry of Education Southeast UniversityNanjing 210096China State key laboratory of Safety Durability and Healthy Operation of Long Span BridgesSoutheast UniversityNanjing 210096China

Modern suspension bridges exhibit a trend of lighter structures,more diversified structural forms,and longer spans,the latter already exceeding two *** performance under dead and live loads depends on their structural and main cable systems,while cablesupported bridges especially rely on the design analysis and construction control of the main *** literary survey systematically analyzes the research progress and state-ofthe-art status quo in the structural systems and design theories of suspension bridges,focusing on the structural systems,main cable shape analyses,live load effect analyses,and emerging lucrative research *** than 100 reliable references have been surveyed.(1)Multi-span or multi-main cable schemes appeal to increasing attention,which may become a better choice in terms of structural systems in scenarios with extremely long spans and heavy *** cable layouts,such as spatial main cables and hybrid cable-stayed suspension systems have also become feasible approaches for enhancing structural stiffness.(2)The shape-finding analysis during the construction phase is more complex and has more essential factors than that of the completed bridge *** theories combining analytical methods and finite element methods are more suitable for the shape-finding analysis of complex cable systems than any single theory of the two,especially for novel cable systems.(3)The live load effect analysis methods based on traditional deflection theory or modified/improved deflection theories still have wide applications,but the refined theory of treating hangers as discrete members is also constantly developing,which is expected to provide new ideas for more complex structural analysis under the different types of live loads and their distribution forms.

关键词： Suspension bridges Structural system Cable analysis Shape-finding analysis Construction control and calculation Live load effect

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Impact factors and pathways of halonitromethanes formation from aspartic acid during LED-UV_(265)/chlorine disinfection

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Frontiers of Environmental Science & Engineering 2024年第1期18卷 129-144页

作者： Liangwen Zhu Tao Wang Qian Tang Qing Wang Lin Deng Jun Hu Chaoqun Tan Rajendra Prasad Singh key laboratory of concrete and Prestressed concrete Structures of Ministry of Education School of Civil EngineeringSoutheast UniversityNanjing 211189China College of Environment Zhejiang University of TechnologyHangzhou 310014China

Light emitting diode (LED-UV)/chlorine disinfection can replace UV/chlorine disinfection in wastewater treatment plants and water supply plants. Halonitromethanes (HNMs) are a class of novel nitrogenous disinfection by-products, which are characterized by higher cytotoxicity and genotoxicity than regulated disinfection by-products. Herein, the impact factors and pathways of HNMs formation from aspartic acid (ASP) were investigated during LED-UV_(265)/chlorine disinfection. The results showed that three types of chlorinated-HNMs (Cl-HNMs) were found during LED-UV265/chlorine disinfection, and their concentrations increased first and then declined as the reaction progressed. Cl-HNMs yields increased with increasing LED-UV_(265) intensity, free chlorine dosage, and ASP concentration, which declined with increasing pH (6.0–8.0). Meantime, the important impact of the coexisting ions contained in water matrices on HNMs formation from ASP was observed during LED-UV_(265)/chlorine disinfection. It was found that copper ions (Cu^(2+)) promoted Cl-HNMs formation. Furthermore, when bromide (Br–) appeared during LED-UV265/chlorine disinfection, nine types of HNMs were detected simultaneously. Moreover, Br– not only converted Cl-HNMs toward brominated (chlorinated)-HNMs and brominated-HNMs but also showed a marked effect on HNMs concentrations and species. Subsequently, the possible pathways of HNMs formation from ASP were proposed during LED-UV_(265)/chlorine disinfection. At last, it was proved that the formation trends of HNMs obtained in the real waters were similar to those in simulated waters. This work elaborated on the influence factors and pathways of HNMs formation, which is conducive to controlling the HNMs produced during LED-UV_(265)/chlorine disinfection.

关键词： LED-UV265 chlorine HNMs Aspartic acid Bromide Copper ions

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Exploration of instantaneous frequency for local control assessment in real-time hybrid simulation

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Earthquake Engineering and Engineering Vibration 2024年第4期23卷 995-1008页

作者： Xu Weijie Peng Changle Guo Tong Chen Cheng key laboratory of concrete and Prestressed concrete Structures of the Ministry of Education Southeast UniversityNanjing 211189China School of Engineering San Francisco State UniversitySan Francisco 94132-1722USA

Local control parameters such as instantaneous delay and instantaneous amplitude play an essential role in evaluating the performance and maintaining the stability of real-time hybrid simulation(RTHS).However,existing methods have limitations in obtaining this local assessment in either the time domain or frequency *** this study,the instantaneous frequency is introduced to determine local control parameters for actuator tracking assessment in a real-time hybrid *** properties,including amplitude,delay,frequency and phase,are then calculated based on analytic signals translated from actuator tracking signals through the Hilbert *** issues are discussed and solutions are proposed for calculation of local control *** simulations are first conducted for sinusoidal and chirp signals with time varying amplitude error and delay to demonstrate the potential of the proposed *** tests also are conducted for a predefined random signal as well as the RTHS of a single degree of freedom structure with a self-centering viscous damper to experimentally verify the effectiveness of the proposed use of the instantaneous *** from the ensuing analysis clearly demonstrate that the instantaneous frequency provides great potential for local control assessment,and the proposed method enables local tracking parameters with good accuracy.

关键词： real-time hybrid simulation tracking assessment instantaneous frequency Hilbert transform

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Pulses in ground motions identified through surface partial matching and their impact on seismic rocking consequence

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 35-50页

作者： Tang Yuchuan Wang Jiankang Wu Gang School of Civil Engineering Southeast UniversityKey Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of EducationNanjing 211102China National and Local Joint Engineering Research Center for Intelligent Construction and Maintenance Nanjing 211102China

In seismology and earthquake engineering,it is fundamental to identify and characterize the pulse-like features in pulse-type ground *** capture the pulses that dominate structural responses,this study establishes congruence and shift relationships between response spectrum surfaces.A similarity search between spectrum surfaces,supplemented with a similarity search in time series,has been applied to characterize the pulse-like features in pulse-type ground *** identified pulses are tested in predicting the rocking consequences of slender rectangular blocks under the original ground ***,the prediction is promising for the majority of the ground motions where the dominant pulse is correctly identified.

关键词： velocity pulse ground motion surface similarity rocking overturning

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Fatigue Crack Propagation Law of Corroded Steel Box Girders in Long Span Bridges

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 201-227页

作者： Ying Wang Longxiao Chao Jun Chen Songbai Jiang key laboratory of concrete and Prestressed concrete Structures of Ministry of Education School of Civil EngineeringSoutheast UniversityNanjing211189China Jiangsu Provincial Engineering Construction Standard Station Nanjing210036China

In order to investigate the fatigue performance of orthotropic anisotropic steel bridge decks,this study realizes the simulation of the welding process through elastic-plastic finite element theory,thermal-structural sequential coupling,and the birth-death element *** simulated welding residual stresses are introduced into the multiscale finite element model of the bridge as the initial ***,the study explores the impact of residual stress on crack propagation in the fatigue-vulnerable components of the corroded steel box *** results indicate that fatigue cracks at the weld toe of the top deck,the weld root of the top deck,and the opening of the transverse diaphragm will not propagate under the action of a standard vehicle ***,the inclusion of residual stress leads to the propagation of these *** considering residual stress,the fatigue crack propagation paths at the weld toe of the transverse diaphragm and the U-rib weld toe align with those observed in actual *** the absence of residual stress,the cracks at the toe of the transverse diaphragm with a 15%mass loss rate are categorized as type I ***,when residual stress is considered,these cracks become I-II composite *** stress significantly alters the cumulative energy release rate of the three ***,incorporating the influence of residual stress is essential when assessing the fatigue performance of corroded steel box girders in long-span bridges.

关键词： Residual stress crack propagation corroded steel box girder cumulative energy release rate

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Study on Evacuation Strategy of Commercial High-Rise Building under Fire Based on FDS and Pathfinder

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Computer Modeling in Engineering & Sciences 2024年第2期138卷 1077-1102页

作者： Zheng Yan Ying Wang Longxiao Chao Jian Guo key laboratory of concrete and Prestressed concrete Structures of Ministry of Education SoutheastUniversityNanjing210096China Nanjing Yang Zi State-Owned Investment Group Nanjing210096China

With the development of economy and society and the growth of population,the high-rise and multi-function of commercial buildings have become an international *** it also poses huge fire *** of the existing studies’research objects are predominantly high-rise residential buildings,without considering the impact of different functional zones(Standard floor,entertainment zone,office zone,equipment room and so on)and personnel distribution of commercial buildings *** the influence of using elevators to carry evacuees on the refuge floor on personnel evacuation is rarely *** this work,the fire scenario of the Yangtze River InternationalConferenceCenter,a high-rise commercial building,is simulated with the Pyrosim programto get the necessary parameters under various fire scenarios and to calculate the available evacuation time *** the same time,according to the complex functional zone of the commercial high-rise building and the distribution of people in different time periods,a reasonable evacuation strategy is developed and simulated by Pathfinder *** results indicate that unorganized evacuation will lead individuals to take the erroneous evacuation route,resulting in a vast region of congestion;comprehensive consideration of the time staggering and the reasonable distribution of evacuation routes can significantly improve evacuation efficiency,and the TRSET of night and working hours is 36.6%–55.3%and 49.9%–79.6%of unorganized evacuation,*** the night fire,60%of the people use elevator-refuge floor to evacuate is the optimal strategy;for the fire during working hours,half of the people on standard floors use the elevator to evacuate and people on multifunctional floors evacuate in four batches is the best *** results of this study can provide viable solutions and a foundation for analyzing the fire evacuation and safety of big commercial high-rise buildings.

关键词： High-rise building fire personnel evacuation refuge floor safety analysis

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Resilience-incorporated seismic risk assessment of precast concrete frames with“dry”connections

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 403-425页

作者： Wu Chenhao Tang Yuchuan Cao Xuyang Wu Gang key laboratory of concrete and Prestressed concrete Structures of the Ministry of Education Nanjing 211102China Department of Civil and Environmental Engineering University of CaliforniaLos AngelesCA 90095USA School of Civil Engineering Southeast UniversityNanjing 211102China College of Civil and Transportation Engineering Hohai UniversityNanjing 210024China

A resilience-incorporated risk assessment framework is proposed and demonstrated in this study to manifest the advantageous seismic resilience of precast concrete frame(PCF)structures with“dry”connections in terms of their low damage and rapid *** framework integrates various uncertainties in the seismic hazard,fragility,capacity,demand,loss functions,and post-earthquake *** this study,the PCF structures are distinguished from ordinary reinforced concrete frame(RCF)structures by characterizing multiple limit states for the PCF based on its unique damage ***,probabilistic story-wise pushover analyses are performed to yield story-wise capacities for the predefined limit *** the seismic resilience analysis,a step-wise recovery model is proposed to idealize the functionality recovery process,with separate considerations of the repair and non-repair *** recovery model leverages the economic loss and downtime to delineate the stochastic post-earthquake recovery curves for the resilience loss *** such,contingencies in the probabilistic post-earthquake repairs are incorporated and the empirical judgments on the recovery parameters are largely *** proposed framework is demonstrated through a comparative study between two“dry”connected PCFs and one RCF designed as alternative structural systems for a prototype *** results from the risk quantification indicate that the PCFs show reduced loss hazards and lower expected losses relative to the ***,the PCF equipped with energy dissipation devices at the“dry”connections largely reduces the expected economic loss,downtime,and resilience loss by 29%,56%,and 60%,respectively,compared to the RCF.

关键词： precast concrete frame non-emulative precast system seismic resilience seismic risk functional recovery

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Frequency-dependent Electrical Capacitance and Resistance of Ultra-high Performance concrete and Their Responses to Compressive Strain

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 968-978页

作者：吴瑜孙明清 ZHU Lutao SONG Qiulei CHEN Jianzhong Hubei key laboratory of Theory and Application of Advanced Materials Mechanics School of ScienceWuhan University of TechnologyWuhan 430070China School of Civil Engineering and Architecture Hubei University of Arts and ScienceXiangyang 441053China Suzhou concrete and Cement Products Research Institude Co. LtdSuzhou 215026China

The frequency-dependent electrical properties and strain self-sensing behaviour of ultra-high performance concrete(UHPC)as cement-based stress/strain self-sensing(CBSS)smart materials were investigated in the frequency range from 100 Hz to 300 *** using the electrical parameters of the equivalent electric circuit model,the quantitative relations of capacitance and conductance of CBSS with the measurement frequency were *** capacitance and the conductance exhibit power-law type dependence on the measurement *** calculated capacitance values at frequencies beyond 2 kHz and conductance values are consistent with the experimental *** sweep-frequency test and the fixed-frequency test were performed to examine effects of the excitation frequencies on strain self-sensing properties of *** fractional change in capacitance(FCC)and resistance(FCR)of CBSS are frequency-dependent in the frequency range from 100 Hz to the f_(B),but frequency-independent in the frequency range from the f_(B)to 300 *** f_(A)and the f_(B)are 1.7-4.0 kHz and 11-78 kHz depending on the fiber dosages,*** and FCR reach their maximum at the f_(A)and 100 Hz,*** responses of capacitance and resistance of CBSS to strain show good repeatability during cyclic *** the fiber dosage increases,capacitance-based sensitivity to strain increases initially and then decreases at the f_(A),and resistance-based sensitivity to strain of CBSS increases with increasing fiber contents.

关键词： UHPC strain self-sensing capacitance-based frequency-dependent

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Effect of coral sand on the mechanical properties and hydration mechanism of magnesium potassium phosphate cement mortar

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第2期25卷 116-129页

作者： Hao LIU Huamei YANG Houzhen WEI Jining YU Qingshan MENG Rongtao YAN College of Civil Engineering and Architecture Guilin University of TechnologyGuilin541004China Guangxi key laboratory of Geomechanics and Geotechnical Engineering Guilin University of TechnologyGuilin541004China State key laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China School of Intelligent Construction Wuchang University of TechnologyWuhan430002China Hydraulic concrete Institute China Three Gorges CorporationBeijing100038China The First Railway Survey and Design Institute Group Corporation Xi’an710043China

Damaged structures on coral islands have been spalling and cracking due to the dual corrosion of tides and *** ensure easy access to aggregate materials,magnesium potassium phosphate cement(MKPC)and coral sand(CS)are mixed to repair damaged structures on coral ***,CS is significantly different from land-sourced sand in mineral composition,particle morphology,and *** has a substantial impact on the hydration characteristics and macroscopic properties of MKPC ***,in this study we investigated the compressive strength,interfacial mechanical properties,and corrosion resistance of MKPC CS *** in the morphology,microstructure,and relative contents of hydration products were revealed by scanning electron microscope-energy dispersive spectrometer(SEM-EDS)and X-ray diffraction(XRD).The results indicated that the compressive strength increased linearly with the interfacial micro-hardness,and then stabilized after long-term immersion in pure water and Na2SO4 solution,showing excellent corrosion *** with MKPC river sand(RS)mortar,the hydration products of CS mortar were an intermediate product 6KPO2·8H2O with a relative content of 3.9%at 1 h and 4.1%at 12 *** hydration product MgKPO_(4)·6H_(2)O increased rapidly after 7-d curing,with an increased growth rate of 1100%.Our results showed that CS promoted the nucleation and formation of hydration products of MKPC,resulting in better crystallinity,tighter overlapping,and a denser interfacial transition *** results of this study provide technical support for applying MKPC mortar as a rapid repair material for damaged structures on coral islands.

关键词： Magnesium potassium phosphate cement(MKPC) Coral sand(CS) Mechanical properties Corrosion resistance Hydration mechanism

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Seismic performance evaluation of water supply pipes installed in a full-scale RC frame structure based on a shaking table test

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 163-178页

作者： Wu Houli Guo Endong Wang Jingyi Dai Xin Dai Chenxi key laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina Earthquake AdministrationHarbin 150080China key laboratory of Earthquake Disaster Mitigation Ministry of Emergency ManagementHarbin 150080China

As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much *** paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete(RC)frame *** material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic *** response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions.A seismic fragility study of displacement demand is conducted based on numerical *** acceleration response and displacement response of different combinations are *** results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes.

关键词： water supply pipe different materials shaking table test amplification factor seismic fragility

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