Digital Commons Network^™

Back‑Calculation Of Subgrade Modulus Based On Genetic Algorithm And Viscoelasticity Theory, Dai Fugui, Wang Xihui, Wu Yaguang, Li Hai

Journal of China & Foreign Highway

To improve the applicability of the PFWD detection method for the back-calculation of subgrade modulus，taking the subgrade splicing project of the west loop line in Nairobi as an example，this paper adopted 3D Kelvin viscoelasticity model and quasi-static response analysis to deduce the displacement function of viscoelastic subgrade under long-term fixed loads，and combined the principle of liner superposition of viscoelasticity with genetic algorithm to propose a new method based on multi-population genetic algorithm for the modulus back-calculation of viscoelastic subgrade.Among them，the corresponding program for back-calculation was written by Matlab.The comparison between theoretical derivation and field tests shows that the peak value …

Correlation Between Pavement Distress And Structural Hidden Distress, Liu Xianming, Xia Han, Hu Dongping, Yan Chen, Yang Rui, Zhong Xinran

Journal of China & Foreign Highway

The hidden distress in the pavement structure does great harm to the performance and service life of the road.In this work，based on the statistical idea of pavement distress rate in the Highway Performance Assessment Standards （JTG 5210—2018），an index of characterizing hidden distress in the pavement structure，namely pavement structure distress rate，was proposed.Based on the actual highway inspection project，the pavement distress and the hidden distress in the depth of 1 m below the pavement of a two-way four-lane highway with a length of 38 km were studied.The overall situation of pavement distress and hidden distress and their spatial distribution were analyzed statistically …

Review Of Evaluation Methods For Mixing Workability Of Asphalt Mixture, Dong Fuqiang, Zu Yuanzhe, Yu Xin, Chen Bei, Liu Lin

Journal of China & Foreign Highway

To clarify the evaluation methods an d research status of mixing workability of asphalt mixture， by consulting relevant research literature in China and abroad and analyzing different evaluation methods，indexes，and research findings of the workability of asphalt mixture，the applicability and evaluation effects of different workability evaluation methods were systematically summarized，and the comparative analysis and comprehensive review were made on the main influencing factors of the mixing workability.The results show that in most evaluation methods for the mixing workability of asphalt mixture，corresponding indexes are constructed to quantitatively evaluate the workability by quantifying the resistance or energy consumption in the mixing process.Besides，in some …

Research Review Of Biomass Ash As Concrete Admixture, Ma Bicong, Liang Jian, Weng Yiling

Journal of China & Foreign Highway

In order to provide a comprehensive overview of research progress in the use of biomass ash as concrete admixture，the physical and chemical properties，mechanism of action，factors affecting the production process of biomass ash，and the effects of biomass ash incorporation on the working properties，mechanical properties，and durability of concrete were studied.The results show that biomass ash has a smaller density and a larger specific surface area than traditional mineral admixture，and the total amount of active components，namely SiO2 + Al2O3 + Fe2O3 （SAF） in most biomass ashes exceeds the requirements of class F volcanic ash （≥70%）.Incorporating biomass ash can effectively improve the mechanical properties …

Structural Repair And Performance Evaluation Of Aged Sbs Modified Asphalt, Xu Guang, Li Qishi, Kuang Huaping, Zhang Henglong, Zhou Ruibo, Chen Yanmei

Journal of China & Foreign Highway

To rejuvenate the excellent performance of aged styrene-butadiene-styrene （SBS） modified asphalt，colza oil bio-asphalt （COA） and polymethylene polyphenyl isocyanate （PAPI） were used in this study for adjusting the asphalt components and repairing SBS molecular structure，respectively.The above-mentioned dual regeneration mechanism was verified by comparing the effects of different rejuvenation components on the physical and rheological properties，as well as the molecular weight distribution of short-term aged SBS modified asphalt.Moreover，according to the change law of rheological properties of unaged base asphalt and SBS modified asphalt under the effect of dual regeneration agent，the influence of the regeneration agent on the phase angle platform area was …

Compaction Characteristics Of Granular Material And Its Structural Mechanical Behavior Considering Orthotropy, Huang You, Zhang Yunbao, Liu Zhaohui, Pan Yu, Liu Zebin, Fang Ronghai

Journal of China & Foreign Highway

The orthotropy of granular materials is closely related to the compaction process and has a significant impact on the mechanical behavior of pavement structures.In this study，in order to study the effect of the compaction process on the orthotropy of granular materials，different compaction methods and compaction energies were employed to compact granular materials for pavement into specimens，and improved dynamic resilient mechanical tests were conducted.Orthotropic coefficients （α2） of typical granular materials were obtained，and the finite element method was used to conduct mechanical analysis of asphalt pavement structures considering the orthotropy of granular materials.The results show that the dry density of specimens by …

Effect Of Basalt Fiber On Strength Of Cement‑Stabilized Macadam Base, Shu Hongbo, Tang Zhengguang, Zhang Yanhong, Bu Xilian, Liang Dong

Journal of China & Foreign Highway

To study the performance of basalt fiber in improving the poor angularity of the crushed cobble base，based on the orthogonal test，this paper determined that the optimal dosage of basalt fiber in the cement-stabilized crushed cobble was 1 kg/m3 （15 mm） + 2 kg/m3 （25 mm）.Besides，unconfined compressive strength and splitting strength tests were carried out on mixtures under three working conditions including the cement-stabilized crushed cobble，cement-stabilized crushed cobble with the optimal dosage of basalt fiber，and cement-stabilized macadam （limestone machine-crushed stone ）.The results show that influenced by the aggregate angularity，the strength of the cement-stabilized macadam （limestone machine-crushed stone ） mixture is better …

Vessel Collision Force And Anti‑Collision Performance Of Long‑Span Beam‑Arch Composite Rigid Frame Bridge, Zhang Wenming, Wang Zhiwei, Lai Yaping

Journal of China & Foreign Highway

Beam-arch composite rigid frame bridge is a new bridge type，and it has few vessel collision studies.By taking the Lijia Jialing River Bridge as the engineering background，the standard value of vessel collision force and anti-collision performance of the long-span beam-arch composite rigid frame bridge were studied.After determining the representative vessel type and vessel collision calculation conditions，the vessel-bridge collision processes of the single-pier models under various calculation scenarios were simulated by using ANSYS/LS-DYNA nonlinear finite element transient dynamic software.The simulation results of collision forces were compared with the results of several empirical formulas.Finally，the full bridge model and the ultimate bearing capacity of …

Installation And Connection Mode Of Stiffening Beam Segment Of Steel Truss Suspension Bridge, Chen Changsong, Wu Junjie

Journal of China & Foreign Highway

During the construction of long-span steel truss suspension bridges，the main girder can be connected in segment-by-segment articulated connection method and rigid-articulated connection combination method.Taking a Yangtze River Highway Bridge in Hubei Province as an example，this paper established the plane calculation model of the full bridge using the Bridge Design and Construction Monitoring System BDCMS to simulate the above two connection methods of the main girder in construction.From the comprehensive analysis of chord member internal forces and line shape of the stiffening beam，this paper finds that the rigid-articulated connection combination method is more appropriate in the construction.In addition，this paper researched the …

Seismic Responses Of Cable‑Sta Yed Bridge Considering Ponding Effect Under Near‑Fa Ult Ground Motions, Lyu Long, Yu Deen, Yuan Yuhang, Yang Huaiyu

Journal of China & Foreign Highway

To study the influence of the pon ding e ffect on seismic responses of the cable-stayed bridge under near-fault ground motions，taking a double-tower cable-stayed bridge as the engineering background，this paper analyzed the ponding response of the main bridge and the main beam of the approach bridge of the cable-stayed bridge under near-fault ground motions and the influence of the ponding response on the structural seismic response.Besides，the influence of viscous dampers and elastic cables on the ponding effect of the cable-stayed bridge under near-fault ground motions was studied，which was compared with the seismic response of the cable-stayed bridge under far-fault ground …

Multi‑Dimensional And Multi‑Point Random Seismic Response Analysis Of Long‑Span Cable‑Stayed Bridges At Different Sites, Shi Yi, Lu Lu, Fan Shuli, Shen Meng, Zuo Chunyuan, Sun Xinguo, Cao Feifei

Journal of China & Foreign Highway

To study the random seismic response of long-span cable-stayed bridges at different sites，the site transfer function was used to evaluate the influence of different site conditions on ground motion propagation.By considering the traveling wave effect and the coherence effect，the multi-point power spectrum under different site conditions was generated.By using the pseudo excitation method for solving the absolute displacement，the seismic responses of cable-stayed bridges under uniform excitation and multi-dimensional and multi-point excitation at different sites were compared.A long-span cable-stayed bridge was selected as an example，and Ansys finite element software was used to analyze the random seismic response of the bridge.By considering …

Experimental Study On Influence Of Stress Ratio On Fatigue Life Of High Strength Steel Wire, Zeng Yi, Yan Donghuang, Xu Hongsheng, Yang Ying

Journal of China & Foreign Highway

To clarify the influence of stress ratio on the fatigue life of high strength steel wire and verify the applicability of the fracture mechanics model to evaluate the fatigue life of steel wire，based on the assumption of equating wire corrosion pits to notches，fatigue tests were carried out on steel wire samples with different prefabricated notch depths at different stress ratios，and a fatigue life empirical equation considering the stress ratio effect was established.The results show that the fatigue life of the steel wire samples is significantly influenced by the stress ratio，which decreases with the increase in the stress ratio.The increase in …

Rigid Domain Optimization Of Steel Truss Joint With Reference To Multi‑Scale Model, Liu Gaocheng, Liu Jian, Dong Chuangwen, Li Chuanxi

Journal of China & Foreign Highway

The rigidity enhancement effect of the integral gusset plate is often simulated in the calculation of an integral nodal steel truss bridge by using a beam element with a rigid arm to improve the calculation accuracy.By taking Zhongshan Lianshwan Bridge as the engineering background，an optimization method based on a multi-scale truss model for nodal rigid domain simulation was proposed and verified.Five consecutive standard sections were selected as the study objects，and the beam element model with rigid arm and the multi-scale model of gusset plate substructure were established by using Ansys.The same boundary and loading conditions were applied.The deflection of the …

Design And Simulation Of Anti‑Collision System On Independent Pile With External Composite, Liao Yuanyuan, Liu Yu, Zhu Lu, Fang Hai, Zhang Jinrui, Han Juan

Journal of China & Foreign Highway

The precise calculation of the ship-bridge collision force is necessary for the assessment of the structural safety of the bridge and the design of an effective anti-collision system.Taking the ship-bridge issue in Furong Bridge in Xiangtan City，this paper compared the collision forces from different angles and in different locations calculated through the finite element software Ansys/LS-DYNA with the results calculated through the empirical formula，thereby determining the fortification collision forces of the bridge piers.Based on the weak anti-collision ability of the bridge double-limb thin-walled pier，the paper designed and implemented a new anti-collision system combined with composite and concrete-filled steel independent piles.The …

Influence Of High Temperature On Large Cantilever Construction Control Of Wide Extradosed Cable‑Stayed Bridge, Zhu Haojie, Zhang Xiedong, Li Yong, Lin Yuan, Wu Di

Journal of China & Foreign Highway

In order to investigate the influence of temperature gradient on the construction of wide extradosed cable-stayed bridges in the large cantilever construction stage at high temperatures，the solar radiation and thermal boundary conditions of wide equal-height box girder were theoretically calculated，and the thermal analysis finite element model of the wide equal-height box girder was established by Abaqus.The cross-section temperature of the box girder was measured by intelligent string sensors and an infrared thermometer.The temperature gradient and its distribution of wide equal-height box girder from sunrise to sunset on a certain day in summer were calculated.The finite element model of the construction …

Method Of Solving Initial Construction Cable Force Of Completed Cable‑Stayed Bridge, Xu Yufeng, Chen Si, Xie Yunfei, Zhu Mengyang

Journal of China & Foreign Highway

To solve the initial construction cable forces of a completed cable-stayed bridge，a method that combines unstressed cable length and forward-iteration is proposed.Firstly，the unstressed length of each cable is calculated according to the completed bridge state.Then，the initial cable forces are obtained by using the unstressed cable length for the forward analysis.The initial construction cable forces are adjusted by difference iteration.Finally，the initial construction cable forces are fine-tuned according to the deformation of the pylon deformation to obtain the bridge completion state that satisfies the deviation requirements.The proposed method is employed in a cable-stayed bridge with a known completion state to calculate the …

Impact Resistance Of Ecc Pipe Piles Based On Ls‑Dyna, Zeng Qingyou, Ye Chenfeng, Liu Junjun, Feng Kai, Cheng Peiyuan, Chen Weihong

Journal of China & Foreign Highway

To study the impact resistance of Engineering Cementitious Composite （ECC） pipe piles，this paper used ANSYS/LS-DYNA to simulate the impact of a vertical drop hammer on the pipe piles.The HJC constitutive model of ECC was established based on key parameters obtained from static tension and compression tests and dynamic compression tests.The correctness of the finite element model was verified by split Hopkinson Pressure Bar （SHPB） tests.The parametric analysis conducted on the pipe pile models compounded with different hammer mass and impact velocity yielded dynamic responses including the displacement，time-history curve of energy，and effective plastic strain diagrams of the pipe piles under various …

Comparative Study Of Different Ventilation Methods During Tunnel Construction, Yue Kun, Bao Xiaohua, Ao Xiang, Liu Kuan, Wu Han, Li Tao, Shen Jun

Journal of China & Foreign Highway

The continuous improvement of tunnel construction technology brings a rapid increase in the speed and mileage of tunnel excavation，during which ventilation is a main problem affecting construction efficiency and safety.Taking the Zhuhai Xingye Express （West Line ） tunnel project as an example，this paper studied the influences of forced ventilation，exhaust ventilation，and hybrid ventilation on the dilution and discharge of harmful gas CO near the tunnel face and the wind speed in the tunnel.The results show that hybrid ventilation performs better in CO dilution，while exhaust ventilation has higher CO emission efficiency with a lower wind speed near the working face.Therefore，although forced ventilation …

Treatment And Measurement Of Water Inrush During Highway Tunnel Construction, Wang C Haojie, Feng Zhihua, Fan Haobo

Journal of China & Foreign Highway

As a special geological condition of highway tunnels，water inrush will cause difficulties in engineering construction technology and management.Unnecessary disputes and management difficulties will emerge when different construction units hold different views about the treatment measures of water inrush，which leads to distributed provisions in the specification and a long treatment period.In view of key problems about the water inrush during highway tunnel construction，including water inrush treatment concept，investigation and estimation，measurement and pricing，and on-site confirmation，this paper systematically sorted out the current regulations and other guiding documents and investigated the treatment methods of tunnel water inrush and reverse slope pumping in China ’s highway …

Stability Of Excavation Face Of Double‑Mode Shield In Earth Pressure Mode Crossing Fault Zone Of Pearl River, Tong Bin, Zhang Bin, Zhu Hanbiao, Wang Shuying

Journal of China & Foreign Highway

In view of the stability of the excavation face of the double-mode shield crossing the fault zone of the Pearl River，the project of the section from Hongshengsha Station to Yufengwei Station of the second phase of Guangzhou Metro Line Seven was studied.Through numerical simulations conducted to analyze the whole area and the local high-risk area of the shield crossing the fault zone of the Pearl River，this paper explored the construction risk of the shield crossing process.Besides，this paper analyzed the influence of different support stresses and grouting pressures on the stability of the excavation face and ground deformation，and finally，the tunneling parameters …

Intelligent Recognition Technology Of Highway Cracks Based On Semantic Segmentation, Gao Liang, Rao Faqiang, Yang Zhongmin, Dai Zongsheng, Sun Hao

Journal of China & Foreign Highway

Real-time detection and timely treatment of highway cracks are crucially fundamental for vehicle safety.Rapid identification and comparison of cracks is a new method for monitoring the development and changes of geological disasters especially when they induce cracks.Therefore，this study proposed an intelligent recognition method of highway cracks based on semantic segmentation，establishing a model with dataset，neural network，calculation parameters，and evaluation indicators to rapidly identify the cracks.The results show that，firstly，when the neural network Attention U-net built in this study semantically segments highway cracks，the binary cross loss function value and accuracy rate reach 0.008 7 and 0.998 4，respectively.Secondly，compared with traditional algorithms，the semantic segmentation method shows …

Overall Design Concept Of Municipal Reconstruction Of Cross‑City Expressway, Fu Yuankun, Zhang Yu

Journal of China & Foreign Highway

The municipal reconstruction of the cross-city expressway is of great significance in enlarging the urban framework，refining the spatial pattern，and promoting the integrated development of clusters.However，China’s expressways seldom undergo municipal reconstruction，with less synergy formed with cities.Therefore，taking one case described above in Hebei Province as an example，this article proposed the overall design concept of integrating with the city from urban space，road networks，municipal facilities，urban ecology，cultural landscape，and other perspectives after analyzing problems in urban space，traffic，industry，landscape and urban quality in existing cross-city expressways. In addition，this paper studied and optimized the municipal reconstruction plan.Holding a theme of “municipalization ”，the plan eliminated the fragmentation of urban space …

Deformation Measurement And Safety Warning Of Highway Bridges Based On Machine Vision, Su Ziyue, Du Wenkang, Lei Dong

Journal of China & Foreign Highway

The structural safety of highway bridges plays a crucial role in traffic safety operations and regional economic development.Due to the rapid increase and complex changes in traffic loads，the demand for real-time monitoring of bridge ’s structural deformation and safety conditions has been increasingly prominent.However，the structural health monitoring system，dominated by contact sensors，has limitations such as difficult installation and construction，complicated maintenance and replacement，and the need to interrupt traffic.To this end，a non-contact deformation measurement system based on machine vision was proposed.Template matching and feature point recognition methods were utilized to achieve recognition of structural surface markings and displacement extraction of key positions.The accuracy …

Development Trend On Raw Materials Market Of Ready‑Mixed Concrete Under Green Construction, Ding Hu, Ding Qingjun, Lin Haojun, Zhang Zhen

Journal of China & Foreign Highway

In the face of resource depletion，high energy consumption in production，high carbon emissions，and serious pollution brought by traditional pumpcrete raw materials，a variety of new raw materials have been gradually developed and promoted to conform with the green construction promoted by China ’s civil engineering industry，witnessing a stable increase in quality，output，and social recognition.High-quality natural river sand and pebbles are in short supply at the origin，and they can be explored in old silted river channels.Gravel and manufactured sand produced using large particle size natural pebbles，limestone，construction waste，and others as raw materials will become new substitutes.In the transformation and upgrading of production enterprises which tend …

Post‑Evaluation Method For Decision‑Making And Implementation Of Highway Maintenance Projects Based On Ahp‑Dematel, Yu Wei, Yang Na, Li Jue

Journal of China & Foreign Highway

Addressing the current lack of post-evaluation management systems related to highways，particularly highway maintenance，this paper proposed a post-evaluation method for the decision-making and implementation of highway maintenance projects based on the combination of analytic hierarchy process （AHP） and decision-making trial and evaluation laboratory （DEMATEL ）.After building a post-evaluation model for the decision-making and implementation of highway maintenance projects and designing the evaluation process，this paper calculated key factors influencing the post-evaluation of the decision-making and implementation of highway maintenance projects and their respective comprehensive weights.The research results indicate that decision-making can possess higher accuracy and efficiency under the above calculation method，providing a …

Lessons Learned From 60 Years Of Pavement Trials In Continental Climate Regions Of Canada And Future Perspective, Wang Di, Li Jingxiao, Ren Xueyuan, Zhang Fan, Yuan Dongdong

Journal of China & Foreign Highway

During the early 1960 s，Canadian road authorities began using stiffer asphalt to address the issue of early rutting in the wheel track zone of asphalt pavements，which was caused by the growing traffic volumes.Pavements constructed with stiffer asphalt commonly exhibit evenly spaced transverse cracks due to the significant internal stresses caused by low temperatures and the inadequate resistance of the asphalt to cracking under such conditions.Research conducted on asphalt pavements with cracks caused by low temperatures has verified the significant impact of asphalt ’s consistency，temperature sensitivity，phase uniformity，and durability.In order to tackle the difficulties presented by the utilization of modified asphalt in …

Scale-Dependent Drivers Of Air-Sea Co2 Flux Variability, Amanda R. Fay, Dustin Carroll, Galen A. Mckinley, Dimitris Menemenlis, Hong Zhang

Faculty Research, Scholarly, and Creative Activity

In climate studies, it is crucial to distinguish between changes caused by natural variability and those resulting from external forcing. Here we use a suite of numerical experiments based on the ECCO-Darwin ocean biogeochemistry model to separate the impact of the atmospheric carbon dioxide (CO2) growth rate and climate on the ocean carbon sink — with a goal of disentangling the space-time variability of the dominant drivers. When globally integrated, the variable atmospheric growth rate and climate exhibit similar magnitude impacts on ocean carbon uptake. At local scales, interannual variability in air-sea CO2 flux is dominated by climate. The implications …

Investigating Students' Expectations And Engagement In General And Organic Chemistry Laboratory Courses, Elizabeth B. Vaughan, Saraswathi Tummuru, Jack Barbera

Chemistry Faculty Publications and Presentations

Students’ expectations for their laboratory coursework are theorized to have an impact on their learning experiences and behaviors, such as engagement. Before students’ expectations and engagement can be explored in different types of undergraduate chemistry laboratory courses, appropriate measures of these constructs must be identified, and evidence of validity and reliability for the data collected with these instruments must be investigated. This study collected evidence related to response process validity, internal structure validity, and single administration reliability for version 2 of the Meaningful Learning in the Laboratory Instrument (MLLIv2) and a measure of student engagement in the undergraduate chemistry laboratory. …

10.28.2024 Orsp Connect, Liz Williamson

ORED Newsletter

ORSP Name Change

RED Talk

Businesses Invited to a Day With NASA

LINC Door Prize Winners

Revealing Grounding Zone And Subglacial Processes At Cosgrove Ice Shelf: Seafloor Analogs For The Modern Antarctic Ice Sheet, Rosemary E. Burkhalter-Castro

USF Tampa Graduate Theses and Dissertations

The future loss of ice in West Antarctica is one of the biggest uncertainties in projections of global sea level rise. The West Antarctic Ice Sheet (WAIS), home to Cosgrove Ice Shelf (CIS), contains enough ice to raise global sea level by more than three meters if it collapsed completely. Accurately predicting how much sea level change may occur from a future collapse of WAIS is of particular interest to low-lying, heavily populated coastal areas such as Florida. For this reason, it is important to understand the processes underpinning rapid changes and retreat at marine-terminating glaciers in the Amundsen Sea. …