Civil and Environmental Engineering Commons^™

Study On Optimal Layout Of Cross ⁃Diaphragm In Oblique Small Box Girder, Mai Xinhao

Journal of China & Foreign Highway

In order to determine the optimal layout of the cross⁃diaphragms in the oblique small box girder, a prestressed concrete small box girder bridge with a 50 m span was taken as the research object, and its internal force under the load of the moving beam was numerically simulated and measured. First, the model was modified according to the measured stress data, and the maximum distance between the cross⁃diaphragms was determined by using the warping-limited normal stress. Then, the height and thickness of the middle cross⁃diaphragms were determined according to the deflection difference coefficient of the bridge span. Finally, according to …

Non⁃Gaussian Features Of Fluctuating Wind Pressures Under Combined Axle Condition, Chen Zhiqiang

Journal of China & Foreign Highway

In view of the non-Gaussian characteristics of wind pressure on the train surface of a typical high-speed railway train and bridge system, the Gaussian variable was expressed as a Hermite polynomial considering non-Gaussian variables by using Hermite series expansion method, and the probability density curve and peak factor of train surface were analyzed. The results show that the Davenport peak factor based on Gaussian distribution obviously underestimates the non-Gaussian peak factor, and its probability density curve deviates from the actual curve of the measuring point. The Hermite series peak factor method based on the modified method takes into account the …

Application Of 3d Reconstruction Model In Inspection Of Bridge Apparent Defects, Xu Guangli, Li Shaoyong, Tang Jun, Liu Shuqi, Zhou Yin

Journal of China & Foreign Highway

In view of problems such as low efficiency, poor accuracy, and imprecise three-dimensional (3D) location of defects in apparent defect inspection of bridges, this paper proposed a method for apparent defect inspection of bridges based on a 3D reconstruction model. By taking the indoor rectangular beam as the object, a three-dimensional bridge model was established, and its accuracy was verified. Then, based on the point cloud data derived from the model, a program was written in Python to realize the identification, measurement, and parameter derivation of apparent defects of bridges. Dade Bridge in Kunming, Yunnan Province was set as the …

Design And Construction Of Steel Caisson For Inclined Pilecap Of Beitstadsund Bridge In Norway, Yang Dingjun

Journal of China & Foreign Highway

At present, the underwater bridge foundation construction technology in China and abroad has been relatively mature, but the different geographical environments, hydrogeological conditions, the form of basic structure, and the available construction equipment lead to different construction schemes and technologies. The Beitstadsund Bridge in Norway is located near the Arctic Circle in central Norway and across the strait. In the design and construction of the deep-water steel cofferdam of the inclined steel pile cap for the bridge, the overall installation of the steel cofferdam was realized by setting the cofferdam support on the inclined steel pipe group, the overall positioning …

Study On Correction Method Of Cable Length Error In Construction Control Of Cable ⁃Stayed Bridges, Huang Gen, Chen Changsong

Journal of China & Foreign Highway

In order to effectively correct the stay cable length error during the construction of the cable-stayed bridge, this paper proposed a correction method with the exposure of the sockets as the error control index and analyzed the influence of the elastic modulus, temperature effect, and anchor point coordinates of the cable on the cable length error from the perspective of construction control. Then, error correction was achieved by adjusting the position of the manufacturing cable length and the nut at the anchor end. The results of application in Jiayu Yangtze River Highway Bridge show that this method can improve the …

Analysis Of Mechanical And Deformation Characteristics Of Karst Tunnel Structure And Research On Treatment Technology, Huang Haifeng, Chang Zhenchao, Luo Junhui, Zhou Xiang, Ceng Fuquan, Tian Fapai

Journal of China & Foreign Highway

Combined with the construction process of Nongmo Karst Tunnel on Du’an–Bama Expressway, this paper used Midas-GTS finite element calculation software to conduct numerical simulation research on the stability of surrounding rock and treatment structure of tunnel with karst caves on either side, analyzed the influence of tunnel excavation on the stress and deformation characteristics of surrounding rock and supporting structure, and probed into the treatment effect of biased wall and root pile on the treatment of karst tunnel. The results show that the surrounding rock at the bottom of the tunnel, the top of the composite foundation, and the top …

Effect Of Temperature And Light On Characteristics Of Asphalt Emissions, Zhu Xuwei, Tian Bo

Journal of China & Foreign Highway

In order to study the effects of temperature and light on the characteristics of asphalt emissions, atmospheric pressure chemical ionization–time-of-flight mass spectrometer (APCI‑TOF MS) and electron impact ionization mass spectrometry (EI‑MS) were used to quantitatively characterize the composition information of PG 62-22 asphalt emissions at different temperatures (40–200 °C). The effects of different temperatures and light on total emission factor, SOA conversion factor, intermediate volatile organic compound (IVOC)/semi-volatile organic compound (SVOC) volume fraction, and aromatics volume fraction of asphalt emissions were studied. The results show that the components of asphalt emissions change with temperature, and the components are complex and …

Study On Triaxial Mechanical Properties Of Glass Fiber Reinforced Cement Soil In Short Age, Wang Wei, Dai Mengdan, Yu Wenjie

Journal of China & Foreign Highway

In order to evaluate the improvement effect of fiber on the brittle damage of cement soil, a triaxial unconsolidated undrained (UU) test was carried out on glass fiber cement soil (GCS) with a curing age of 7 d and a mass fraction of glass fiber (GF) of 0, 2‰, 4‰, 6‰, and 8‰, respectively. The results show that: ① GCS retains the original strain softening characteristics of cement soil; ② For the same mass fraction of GF, the peak stress, peak strain, and residual strength of GCS samples increase gradually with the increase in confining pressure, but the brittleness index …

Study On Experimental Application Of Xinjiang Steel Slag In Cement Stabilized Base, Chen Wei, Yu Haiming, Li Qian, Huang Yong, Si Yi

Journal of China & Foreign Highway

Based on the experimental study of Xinjiang steel slag in cement-stabilized base, the physical and chemical characteristics of steel slag were analyzed, and the unconfined compressive strength, splitting strength, and dry shrinkage performance of cement-stabilized steel slag and gravel mixture with different cement dosages (4% and 5%) and steel slag contents (30%, 40%, and 60%) were analyzed. The test results show that steel slag can be used as a good engineering aggregate in a cement-stabilized base, and with the addition of steel slag, the unconfined compressive strength and splitting strength of steel slag and gravel mixture are increased to varying …

Mechanical Properties And Micro Analysis Of Cement Stabilized Steel Slag Macadam Base, Wan Tianbao

Journal of China & Foreign Highway

With steel slag as coarse aggregate, cement-stabilized steel slag macadam base material was designed and prepared by selecting three kinds of cement dosage and three kinds of steel slag content. The mechanical properties of cement-stabilized steel slag macadam base were studied through compaction and unconfined compressive strength tests, and XRD and SEM microscopic tests were carried out to analyze the mineral composition and microscopic morphology of steel slag and mixture and clarify the internal mechanism of hydration product formation and microstructure and strength formation. The results show that the maximum dry density and optimum moisture content of cement-stabilized steel slag …

Analysis Of Influence Of Moisture Content ⁃Temperature Dual Factor On Mechanical Properties Of Red Clay, Wang Jiangtao, Bao Temenbaiyila, Yang Weiguang, Zhou Qi, Fu Helin

Journal of China & Foreign Highway

Under the new climatic environment and engineering construction requirements, engineering problems involving red clay are becoming more and more prominent, and it is urgent to deeply grasp the mechanical and engineering properties of residual slope red clay. The typical red clay in Hunan Province was studied in this paper. Based on the unconsolidated undrained direct shear test, this paper studied the mechanical properties of residual slope red clay under the influence of moisture content and temperature, focusing on the most unfavorable conditions affecting the mechanical properties of red clay. The results show that: ① The shear strength of red clay …

Traffic Conflict Analysis Of Multila Neexpressway Based On Simulation, Ceng Yuekai, Zhou Tao, Chen Yazhen

Journal of China & Foreign Highway

In order to prevent traffic accidents on multi-lane expressways, the VISSIM traffic simulation model was established based on three types of multi-lane traffic conflicts: mixed passenger and cargo type, separated passenger and cargo type, and separated main and auxiliary type. SSAM software was used to obtain traffic conflict data, and the form, quantity, and location of the conflicts were analyzed. The results show that traffic conflicts are the most under the mixed passenger and cargo type, which are mainly distributed in the upper 100 m range of the innermost lane, outermost lane, and deceleration lane. The traffic conflicts under the …

Risk Analysis Of Highway Nighttime Maintenance Operation Based On Sem, Fan Jinhua, Zou Leping, Qi Shaoren, Tian Zhen

Journal of China & Foreign Highway

In order to analyze the factors affecting the risk of nighttime expressway maintenance operation and quantitatively assess the degree of influence of various factors on the risk of nighttime maintenance operation, this paper extracted five first-level indicators and 36 second-level indicators that affect the risk of operation through literature review, accident data, and questionnaire survey and built an evaluation system. The first-order and second-order confirmatory factor analysis models were constructed by using a structural equation model (SEM) based on 343 questionnaires of the nighttime maintenance operation risks. The results show that the driver factor has the greatest effect on the …

Study On Effectiveness Evaluation Method Of Expressway Drainage System In Rainy Area, Luo Datian, Li Jiayi, Zou Jingrong

Journal of China & Foreign Highway

In order to comprehensively evaluate the effectiveness of expressway drainage systems in rainy areas and comprehensively analyze the factors affecting the effectiveness of drainage systems, this paper took the perfection of drainage system, stability of drainage facilities, and road traffic safety as the first-level evaluation index and six kinds of influencing factors such as the degree of integrity as the second-level index, and it put forward the evaluation criteria of the effectiveness of expressway drainage system in rainy areas. The fuzzy comprehensive evaluation method was used to determine the membership degree of expert scoring through the trapezoid membership function, and …

Research On Crack And Permeability Characteristics Of Cement ⁃Modified Expansive Soil Under Dry ⁃Wet Cycles, Bao Guiyong, Xu Yangshaojun, Jiang Zhijie, Rong Hongliu, Wang Jinlong

Journal of China & Foreign Highway

In order to study the engineering permeability characteristics of cement-modified expansive soil under dry and wet cycles, the mix ratio of cement-modified expansive soil was designed, and the orthogonal design test method was adopted. Image analysis software PACS, unconfined compressive strength test, and laboratory permeability test were used to study the crack development, strength attenuation characteristics, and permeability changes of cement-modified expansive soil under dry and wet cycle conditions. The results show that soil permeability and strength are greatly affected by the number of dry and wet cycles. Under the condition of dry and wet cycles, the moisture content of …

Assessing The Impact Of Spatial Resolution Of Uas-Based Remote Sensing And Spectral Resolution Of Proximal Sensing On Crop Nitrogen Retrieval Accuracy, Kianoosh Hassani, Hamed Gholizadeh, Saleh Taghvaeian, Victoria Natalie, Jonathan Carpenter, Jamey Jacob

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Foliar nitrogen (N) plays a central role in photosynthetic machinery of plants, regulating their growth rates. However, field-based methods for monitoring plant N concentration are costly and limited in their ability to cover large spatial extents. In this study, we had two objectives: (1) assess the capability of unoccupied aerial system (UAS) and non-imaging spectroscopic data in estimating sorghum and corn N concentration and (2) determine the impact of spatial and spectral resolution of reflectance data on estimating sorghum and corn N concentration. We used a UAS and an ASD spectroradiometer to collect canopy- and leaf-level spectral data from sorghum …

Exploring The Determinants Of Organic Matter Bioavailability Through Substrate-Explicit Thermodynamic Modeling, Firnaaz Ahamed, Yaqi You, Amy Burgin, James C. Stegen, Timothy D. Scheibe, Hyun-Seob Song

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Microbial decomposition of organic matter (OM) in river corridors is a major driver of nutrient and energy cycles in natural ecosystems. Recent advances in omics technologies enabled high-throughput generation of molecular data that could be used to inform biogeochemical models. With ultrahigh-resolution OM data becoming more readily available, in particular, the substrate-explicit thermodynamic modeling (SXTM) has emerged as a promising approach due to its ability to predict OM degradation and respiration rates from chemical formulae of compounds. This model implicitly assumes that all detected organic compounds are bioavailable, and that aerobic respiration is driven solely by thermodynamics. Despite promising demonstrations …

Analysis Of Evolution And Morphology Of Urban And Road Networks: Case Study Lebanon-Nabatiyeh Area, Amal Al Ghorayeb, Adel Elkordi, Ghaleb Faour, Zeinab Jaber, Youssef Attallah

BAU Journal - Science and Technology

This study examines the morphology and evolution of urban and road networks and their relationship with topography in the Lebanon-Nabatiyeh area, by using GIS and remote sensing data. and calculate the annual urban growth percentage rate. The results reveal a clear relationship between the morphology of urban and road networks and their evolution over four periods, as well as the influence of the surrounding topography on their configuration. The study recommends that urban areas should be developed in areas with a slope range of 15º or more to improve the urban structure and infrastructure surrounding them. Understanding the evolution and …

Methods And Surface Materials Repair For Concrete Structures – A Review, Lelian W. Elkhatib, Adel Elkordi, Jamal Khatib

BAU Journal - Science and Technology

Concrete is a very critical material that may require maintenance and possible repair periodically, especially in important structure such as bridges. In general, concrete in structures (e.g. reinforced concrete) may be subjected to cracks due to a variety of reasons. These include, design and external environments such as the ingress of harmful ions into the concrete, unexpected extra loads including earthquakes. These cracks can affect not only the appearance of the structure but more importantly the structural performance of concrete and the integrity of the concrete structure. Therefore, when cracks occur a proper repair method should be selected, based on …

Mechanical And Durability Properties Of Fly Ash Geopolymer Concrete – A Review, Ali Shebli, Jamal Khatib, Adel Elkordi

BAU Journal - Science and Technology

Geopolymers have emerged as a promising alternative for Ordinary portland cement (OPC) in construction industry, due to their potential to minimize the emissions of carbon dioxide (CO₂) and improve the efficiency of waste recycling. This paper aims to study the fresh and hardened properties of fly ash geopolymer concrete (GPC), as well as to review the raw materials used in the production of geopolymers. Several factors impact the mechanical and durability properties of fly ash GPC, including the specific type of fly ash utilized, the curing temperature, the alkaline activator (AA) concentration, and the type of AA used. …

Understanding The Flow Dynamics Of The Pearl River, Ms, Through Hydrodynamic Modeling, Nahruma Mehzabeen Pieu

Master's Theses

The Pearl River brings fresh water and nutrients into Lake Borgne regulating conditions for oyster growth in estuarine waters. However, there are no flow measurement stations installed on East Pearl or West Pearl either at the river outlets or after the upstream bifurcation of the Pearl. This study aims to model the Lower Pearl River to understand the flow dynamics in the major branches, and to determine the final outflow distribution into the Mississippi Sound, aiming to improve river forcing for ocean models studying estuarine dynamics of the Mississippi Sound.

Synthetic meandering bathymetry with updated banks is developed and applied …

Maize Nitrogen Uptake, Grain Nitrogen Concentration And Root-Zone Residual Nitrate Nitrogen Response Under Center Pivot, Subsurface Drip And Surface (Furrow) Irrigation, Suat Irmak, Ali T. Mohammed, Matthew Drudik

Department of Agricultural and Biological Systems Engineering: Faculty Publications

While the impact(s) of irrigation and nitrogen (N) levels on crop yields have been investigated separately, research lacks about how different irrigation methods coupled with different N application timing strategies under full and limited irrigation levels effect yield, soil nitrate nitrogen (NO₃-N) residual and stover N uptake. Knowledge of these dynamics can help to establish effective water and N management guidelines for the same crop under different irrigation methods and irrigation levels. This research investigated maize (Zea mays L.) residual soil NO₃-N concentration and stover and grain N uptake response to water under different irrigation …

Investigation Of Placement Of Polyethylenimine Within Thin Film Composite Reverse Osmosis Membranes For Enhanced Anti-Fouling Properties, Taylor F. Austin

Master's Theses

Fresh water scarcity is an alarming issue for communities across the globe. The development of water recycling and reuse technologies has become crucial in expanding the limited water resources. Reverse osmosis (RO) is among the key processes that can treat wastewater to meet potable water reuse standards. Despite the advancements in RO membrane technologies, many challenges persist regarding the operation and maintenance of RO membranes, such as membrane fouling. Extensive research investigations have focused on developing RO membrane modifications to combat the decreased performance due to fouling. Polyethylenimine (PEI) is a promising polymer used for enhancing the anti-fouling properties of …

Enhancing Construction Safety Training Of Bridges Using Augmented Reality And Virtual Reality, Mohamed Sherif Elrifaee

Theses and Dissertations

Infrastructure development projects are widely acknowledged as some of the most complex and challenging projects to undertake. The construction of bridges, in particular, has proven to be a significant safety risk for workers, with a considerable number of accidents reported on construction sites. There is a lack of comprehensive training programs specifically designed for bridge construction safety, and only a few studies have explored the use of both AR and VR to enhance safety training in construction. As such, this research aims to improve the safety of bridge construction sites through the implementation of Augmented Reality (AR) and Virtual Reality …

Integration Of Environmental Sustainability And Decision Making: Case Studies Of Civil Infrastructure, Sussan Moussavi

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Sustainable development is important in the planning and design of critical civil infrastructure systems. However, decision making related to these systems currently lacks meaningful sustainability considerations. To fill this gap, this research explores the life cycle impacts of wastewater and energy infrastructure using case studies, life cycle assessment methodologies, and stakeholder discussions. Environmental and economic impacts, which are more commonly quantified, as well as more difficult to quantify societal factors, are explored. The goal of this research is to help inform decision making and facilitate the consideration of the three pillars of sustainability (e.g., economic, environmental, and social) during the …

Engineering A Multicompartment In Vitro Model For Dorsal Root Ganglia Phenotypic Assessment, Sydney M. Caparaso, Adan Redwine, Rebecca A. Wachs

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Despite the significant global prevalence of chronic pain, current methods to identify pain therapeutics often fail translation to the clinic. Phenotypic screening platforms rely on modeling and assessing key pathologies relevant to chronic pain, improving predictive capability. Patients with chronic pain often present with sensitization of primary sensory neurons (that extend from dorsal root ganglia [DRG]). During neuronal sensitization, painful nociceptors display lowered stimulation thresholds. To model neuronal excitability, it is necessary to maintain three key anatomical features of DRGs to have a physiologically relevant platform: (1) isolation between DRG cell bodies and neurons, (2) 3D platform to preserve cell–cell …

Post-Processed Data And Graphical Tools For A Conus-Wide Eddy Flux Evapotranspiration Dataset, J. M. Volk, J. L. Huntington, F. Melton, B. Minor, T. Wang, S. Anapalli, R. G. Anderson, S. Evett, A. French, R. Jasoni, N. Bambach, W. P. Kustas, J. Alfieri, J. Prueger, L. Hipps, L. Mckee, S. J. Castro, M. M. Alsina, A. J. Mcelrone, M. Reba, B. Runkle, M. Saber, C. Sanchez, E. Tajfar, R. Allen, M. Anderson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Large sample datasets of in situ evapotranspiration (ET) measurements with well documented data provenance and quality assurance are critical for water management and many fields of earth science research. We present a post-processed ET oriented dataset at daily and monthly timesteps, from 161 stations, including 148 eddy covariance flux towers, that were chosen based on their data quality from nearly 350 stations across the contiguous United States. In addition to ET, the data includes energy and heat fluxes, meteorological measurements, and reference ET downloaded from grid- MET for each flux station. Data processing techniques were conducted in a reproducible manner …

Soybean Crop Coefficients Under Different Seeding Rates And Full And Limited Irrigation And Rainfed Management, Suat Irmak, Rupinder Sandhu

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The effects of soybean seeding rates on evapotranspiration (ET_c) and grassand alfalfa-reference crop coefficients (K_co and K_cr) were investigated under five seeding rates (185,250, 247,000, 308,750, 370,500 and 432,250 seeds ha^-1) (62, 82, 103, 124 and 144% of the recommended seeding rate of 300,000 seeds ha^-1 in the experimental region) and different irrigation strategies (i.e. full irrigation treatment [FIT], limited irrigation of 75% FIT and 50% FIT and rainfed treatment). K_co and K_cr values were developed for each soybean growth stage. The seasonal ET_c ranged from 460 mm for …

Streambank Erosion Phenomena And Understanding: Current Research And Future Directions, Celso Castro-Bolinaga, Aaron R. Mittelstet, Kyle Mankin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Streams are in dynamic equilibrium with their environments, and as that environment is altered by human development and changing climate, streambank erosion is a common, but little understood, result. This article highlights the contributions of the special collection “Streambank Erosion, Sediment Dynamics, and Restoration (SER),” which assembled six studies that represent key advances in streambank erosion research, highlight current research in the field, and identify directions for future research. The studies in this special collection were grouped into three central themes: (1) streambank erosion monitoring, (2) streambank erodibility characterization, and (3) streambank erosion loading. In this article, key findings within …

Toward Automated Irrigation Management With Integrated Crop Water Stress Index And Spatial Soil Water Balance, Sandeep Bhatti, Derek M. Heeren, Susan A. O’Shaughnessy, Christopher M. U. Neale, Jacob Larue, Steve Melvin, Eric Wilkening, Geng Bai

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Decision support systems intended for precision irrigation aim at reducing irrigation applications while optimizing crop yield to achieve maximum crop water productivity (CWP). These systems incorporate on-site sensor data, remote sensing inputs, and advanced algorithms with spatial and temporal characteristics to compute precise crop water needs. The availability of variable rate irrigation (VRI) systems enables irrigation applications at a sub-field scale. The combination of an appropriate VRI system along with a precise decision support system would be ideal for improved CWP. The objective of this study was to compare and evaluate two decision support systems in terms of seasonal applied …