Mesoscopic Numerical Simulation Of Concrete Cracking Caused By Nonuniform Corrosion Of Strands,
2024
Nanchang Urban Planning & Design Institute Group Co ., Ltd, Nanchang , Jiangxi 330000 , China
Mesoscopic Numerical Simulation Of Concrete Cracking Caused By Nonuniform Corrosion Of Strands, Zeng Tianbao, Chen Hong, Huang Xiaoqi, Tu Ronghui, Dai Lizhao
Journal of China & Foreign Highway
The non-uniform corrosion of spinning strands will induce concrete cracking.A non-uniform expansion model of corrosion products of strands was established，and a mesoscopic numerical model of concrete cracking caused by non-uniform corrosion of strands was built.Concrete was considered as a three-phase composite material composed of mortar matrix，aggregate，and interface layer.The concrete cracking behavior caused by the non-uniform corrosion of strands was simulated by embedding cohesive elements.The rationality of the proposed model was verified by existing experimental data，and the influence of protective layer thickness and aggregate content of concrete on the width of corrosion-induced cracks was discussed.The results show that the proposed non-uniform …
Parameter Sensitivity Analysis Of Single‑Tower Cable‑Stayed Bridge With Mixed Beam,
2024
School of Civil Engineering and Architecture , Wuyi University , Jiangmen , Guangdong 529000 , China
Parameter Sensitivity Analysis Of Single‑Tower Cable‑Stayed Bridge With Mixed Beam, Chen Kongliang, Ye Jianxin, Xu Yufeng, Huang Zhuobin, Guo Fengtao
Journal of China & Foreign Highway
To improve the efficiency of the review simulation model of the bridge monitoring unit and study the influence of different parameters of the single-tower mixed beam cable-stayed bridge on the bridge ’s completed state in the construction process，this paper，taking the cable-stayed bridge of Tongji Road in Foshan with a span of （200+68+46） m as the engineering background，adopted the single control variable method and response surface-Monte Carlo method for sensitivity analysis.Taking the main beam alignment，main tower alignment，main beam stress，and the variation of cable-stayed bridge force as control objectives，this paper studied the influence of the variation of main beam weight，initial tensile force，and …
Key Technology And Numerical Simulation Of Cast‑In‑Place Construction Of Main Arch Ring Of Reinforced Concrete Arch Bridge Based On Suspension Steel Arch Method,
2024
CCCC Guangzhou Waterway Bureau Co ., Ltd., Guangzhou , Guangdong 510290 , China
Key Technology And Numerical Simulation Of Cast‑In‑Place Construction Of Main Arch Ring Of Reinforced Concrete Arch Bridge Based On Suspension Steel Arch Method, Su Xueping, Xia Zhengzhi, Lyu Songgang, Duan Pengjie, Lyu Yigang
Journal of China & Foreign Highway
Steel arch frame replaced such construction methods as floor bracket or segment cantilever assembly and it was applied to arch circle cast-in-place across deep water canyons in mountainous areas，which had certain advantages and was worth promoting and applying.By introducing the key construction technologies of Sanchahe Bridge，including steel arch frame cantilever fastener method assembly，arch water tank method precompression，and main arch ring layered pouring，the common problems in the construction process of crossing the deep water canyon were solved effectively.Based on Midas Civil overall modeling of finite elements，the key construction technologies adopted by the bridge were numerically simulated and analyzed，and the successful construction …
Design And Installation Technology Of Hanging Basket For Long‑Span Concrete Girder Cable‑Stayed Bridge,
2024
CCCC Second Harbor Engineering Co ., Ltd., No.5 Branch , Wuhan , Hubei 430040 , China
Design And Installation Technology Of Hanging Basket For Long‑Span Concrete Girder Cable‑Stayed Bridge, Zeng Xianliu, Pang Jianguo, Chen Cheng
Journal of China & Foreign Highway
The main bridge of Zhungeer Yellow River Super Major Bridge is a （160+440+160） m double tower double cable plane full floating system concrete grider cable-stayed bridge.The main beam is a 28.4m wide double box prestressed concrete structure.It was constructed by cantilever pouring with a front fulcrum hanging basket.The maximum weight of the cantilever pouring section is 5 800 kN.To ensure the integral rigidity of the hanging basket，the hanging basket bearing platform adopted the steel box girder structure.The long and large components were connected by high-strength bolts made in sections to facilitate the transportation and installation of the hanging basket.The hanging …
Key Construction Techniques For Emended Cap Unsealed Bottom Of Deep‑Water Hard Rock,
2024
CCCC Second Harbor Engineering Co ., Ltd., Wuhan , Hubei 430014 , China ;Transportation Industry Key Laboratory of Large-Span Bridge Construction Technology , Wuhan Hubei 430014 , China ;Research and Development Center of Intelligent Manufacturing Technologies of Transport Industry Infrastructure , Wuhan , Hubei 430014 , China
Key Construction Techniques For Emended Cap Unsealed Bottom Of Deep‑Water Hard Rock, Zeng Jian, Guan Xiaohui, Guo Zhiwei
Journal of China & Foreign Highway
In the construction of a deep-water embedded cap foundation，it was required to excavate the mud surface to the depth below sealing concrete and clean the bottom carefully，ensuring the height and quality of bottoming concrete.For hard rock under good geological conditions，there exist such problems as difficulty in excavation，long excavation time consumption，and high construction cost.Based on the construction of the main pier caps of the Chongqing Jiahua Metro Bridge，this paper adopted the method of combining theoretical analysis，numerical calculation，and engineering implementation verification，which developed an emended cap unsealed bottom key construction techniques for deep-water hard rock.This construction technology used the method of excavating the …
Influence Of Blasting Point Position And Foundation Pit Height On Blasting Vibration During Foundation Pit Blasting Excavation,
2024
Shanghai Tunnel Engineering Co ., Ltd, Shanghai 200232 , China
Influence Of Blasting Point Position And Foundation Pit Height On Blasting Vibration During Foundation Pit Blasting Excavation, Liu Kuan, Xu Zhihao, Tang Yuan, Shen Jun, Bao Xiaohua, Shen Pinghuan, Ou Yang
Journal of China & Foreign Highway
In view of inaccurate vibration prediction of foundation pit blasting，the influence of blasting point position and foundation pit height on vibration during foundation pit blasting excavation was studied by using finite element simulation software.First，based on the foundation pit blasting excavation of the Mawan Cross-Sea Passage，a numerical simulation was carried out to verify the applicability of the model.Then，under unchanged blasting center distance，the distance from the blasting point to the edge of the foundation pit and the foundation pit height were changed respectively，and the influence of these two factors on surface vibration was studied.The results show that a greater distance from the …
Reasonable Construction Method For Grade Ⅳ Surrounding Rock In Single‑Hole Four‑Lane Super‑Span Highway Tunnel,
2024
CCCC-SHB Fourth Engineering Co ., Ltd., Luoyang , Henan 471013 , China
Reasonable Construction Method For Grade Ⅳ Surrounding Rock In Single‑Hole Four‑Lane Super‑Span Highway Tunnel, Li Heyin, Gao Jingming, Li Yanfeng, Xun Wenjie, Dong Fangfang, Zhang Jiangang
Journal of China & Foreign Highway
In order to study the reasonable constr uction method of super-span highway tunnels，the Xinghuacun No.1 tunnel included in the reconstruction and expansion project of the Xiaocaohu –Urumqi section of the Lianyungang –Khorgos Expressway in Xinjiang was studied.The numerical simulation method was used to analyze the deformation and stress of the supporting structure of the Grade tisurrounding rock in the super-span highway tunnel constructed by the center diaphragm （CD） method，the upper-bench CD method，and the three-bench and seven-step excavation method.Under the premise that the deformation and the stress of the supporting structure met the design requirements，the advantages and disadvantages of each construction …
Excavation Method For Ⅴⅴ‑Grade Surrounding Rock Of Double‑Hole Eight‑Lane Super‑Long‑Span Tunnel,
2024
School of Civil Engineering & Architecture ， Xiamen University of Technology ， Xiamen， Fujian 361024， China
Excavation Method For Ⅴⅴ‑Grade Surrounding Rock Of Double‑Hole Eight‑Lane Super‑Long‑Span Tunnel, Shi Youzhi, Liu Xudong, Yong Jinzhu
Journal of China & Foreign Highway
In order to reduce the adverse effect of back heading blasting on the completed supporting structure at the entrance of a double-hole eight-lane super-long-span tunnel with Ⅴ-grade surrounding rock，the Niuzhaishan tunnel project in Pingtan was taken as an example.The original design of the double-side heading method is easy to cause the collapse of the temporary steel support that has been completed when blasting happens near the back heading.In view of this，this paper put forward scheme 1 of canceling the temporary transverse support and the up-and-down step method with vertical support （scheme 2）.It then used the finite element method to calculate …
Influence Of Concrete Barrier Slope Parameters On Protective Effect Against Vehicle Collision,
2024
Beijing Hualuan Traffic Technology Co ., Ltd., Beijing 100070 , China
Influence Of Concrete Barrier Slope Parameters On Protective Effect Against Vehicle Collision, Gong Shuai
Journal of China & Foreign Highway
In order to study the influence of concrete barrier slope parameters on the protective effect against vehicle collision，the vehicle models and concrete barrier models were established.The validity of these models was verified using the real vehicle test data.Then，the collision analysis was conducted on the single-slope concrete barrier with different slopes，improved concrete barrier with different slope parameter combinations，and reinforced concrete barrier with anti-climbing function by using the validated models，respectively.The results show that the slope is the key parameter that affects the protective performance of the single-slope barrier，and vehicles cannot be effectively protected if the slope is too small or too large.The …
Design And Evaluation Of Land‑Saving And Beautiful Median Barriers,
2024
Shandong Jinyu Information Technology Group Co ., Ltd., Jinan , Shandong 250101 , China
Design And Evaluation Of Land‑Saving And Beautiful Median Barriers, Li Jingjun, Wa Ng Xin, Qi Jie, Wang Zijian, Liu Siyuan
Journal of China & Foreign Highway
During the construction and expansion of expressways and national and provincial highways，more diversified requirements have been put forward for the median barrier，including reliable protective performance，small footprints，beautiful traffic environments，and economic costs.However，the existing median barrier achievements still have some shortcomings.In order to better meet the design and use needs of median barriers for highways，theoretical analysis，computer simulation，and full-scale impact tests with real vehicles were adopted，and the force characteristics of different types of median barriers were analyzed.A new design concept of beam-column integration was put forward.Through systematic research on the barrier height，width，beam，column，foundation，and other structures，a land-saving and beautiful median barrier was developed.The median barrier had …
Guardrail Improvement For Old Bridges In Expressways,
2024
Jiangsu Guoqiang Traffic Science & Technology Co ., Ltd., Nanjing , Jiangsu 210000 , China
Guardrail Improvement For Old Bridges In Expressways, Liu Xinping, Zhang Shihui, Shang Zhongping, Han Yue, Zhang Qiang
Journal of China & Foreign Highway
In view of the insufficient protection grade of the guardrail in old bridges，a combined guardrail suitable for the low concrete wall guardrail in the old bridge was designed and developed by using finite element analysis while not damaging the main structure of the bridge.The protection grade was verified to reach SA grade through a full-scale vehicle collision test.The guardrail was designed with new high-strength alloy steel，with light weight and beautiful appearance.There was no need to dismantle the original concrete foundation in the old bridge，which is convenient for construction and requires low cost.Therefore，it is worth being popularized and applied in the …
Research And Field Test On Ultra‑Thin Wearing Course Based On Balanced Design Concept,
2024
Anhui Transportation Holding Group Co ., Ltd.， Hefei， Anhui 230088， China
Research And Field Test On Ultra‑Thin Wearing Course Based On Balanced Design Concept, Gu Jianjun, Li Xia, Li Atan, Sun Qiang, Li Jie, Jiang Zhaowei
Journal of China & Foreign Highway
To address the application of an ultra-thin wearing course in expressway asphalt pavement maintenance engineering，the ultra-thin wearing course system based on the balance design concept was systematically studied.In this paper，the action mechanism and application characteristics of modifiers were analyzed，and the proportion design test of the ultra-thin wearing course was designed based on the balance design method.Finally，according to the proportion design test，the optimal proportion of the ultra-thin wearing course material was selected for test road paving.Research shows that the direct-cast high viscosity modifier is convenient for transportation and storage，improves the elastic recovery of asphalt mixtures and reduces permanent deformation.Under the condition …
Intelligent Bridge Lifecycl E Maintenance System Based On Long‑Term Inspection,
2024
Shenzhen Road & Bridge Group Co ., Ltd., Shenzhen , Guangdong 518000 , China
Intelligent Bridge Lifecycl E Maintenance System Based On Long‑Term Inspection, Ye Zhiwei, Zhang Jiaxin, Tan Haishan, Fan Lei, He Wen, Dong You, Wu Wanglin
Journal of China & Foreign Highway
The current bridge maintenance sy stem in China primarily relies on bridge inspection data to prioritize the state of bridges and allocate a limited budget accordingly.This strategy focuses on repairing bridges with low performance，concentrating on restorative maintenance but ignoring preventive maintenance.In view of the total lifecycle cost，the repair-oriented method may require a lower initial investment but leads to significant resource consumption in the mid to late stages.Based on existing highway bridge maintenance systems，an intelligent maintenance system relying on Chinese standards and bridge inspection data and combining repair and prevention was developed.The system model mainly consisted of two modules：the bridge performance …
Improvement Of Gravelly Laterite And Cement Stable Disposal In West Africa,
2024
China Road and Bridge Corporation , Beijing 100011 , China
Improvement Of Gravelly Laterite And Cement Stable Disposal In West Africa, Jin Haibing, Yi Zicheng, Zhuo Rong
Journal of China & Foreign Highway
Owing to poor gradation and high liquid limit and plasticity index，the application of gravel laterite on road paving is limited in West Africa.To overcome this issue，laterite granule combined with sand at different content was explored.The performance including the particle composition，limit water content and CBR value was investigated.The results indicate that sand treatment can improve the gradation，enhance the compactness，and reduce the plasticity index.The improved gravel laterite can meet the requirements of subbase，cushion，and base courses.Cement treatment can improve the mechanical properties of laterite grains.Cement and sand content affect the unconfined compressive strength significantly，with an optimal sand content range identified.Specifically，laterite granules mixed with …
Review Of Cyclic Voltammetry Measurements For Uranium In Flinak Molten Salt,
2024
Brigham Young University
Review Of Cyclic Voltammetry Measurements For Uranium In Flinak Molten Salt, Jackson Ivory
Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)
The electrochemical behavior of uranium FLiNaK molten salts is explored, focusing on cyclic voltammetry (CV) as a powerful tool for redox characterization and diffusion studies. Through a comprehensive review of recent research, the study highlights the significance of CV in understanding electrode kinetics, material compatibility, and process optimization in molten salt environments. The findings underscore the potential of FLiNaK molten salt reactors in advancing nuclear energy technologies, fuel processing, and waste management strategies. Collaborative interdisciplinary efforts are emphasized to address challenges and accelerate innovation in electrochemical methods for nuclear applications.
An Overview Of How To Measure The Kinetic Properties Of An Anode Material For The Chlorine Evolution Reaction,
2024
Brigham Young University
An Overview Of How To Measure The Kinetic Properties Of An Anode Material For The Chlorine Evolution Reaction, Cameron Vann
Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)
The process of generating chlorine gas using electrolysis in aqueous systems is well established. However, a new process requires chlorine to be generated at high temperatures using molten salt. This harsh environment requires a new study of anode materials for the chlorine evolution reaction. Anode materials can be compared by their kinetic parameters, the transfer coefficient α and the exchange current i0. The basic theory of these properties as they relate to the chlorine evolution reaction has been detailed and an analysis method for finding these effective parameters has been shown and demonstrated.
Selective Separation Of Metal Ions From Aqueous Process Streams Using Magnetite Adsorbent,
2024
Montana Technological University
Selective Separation Of Metal Ions From Aqueous Process Streams Using Magnetite Adsorbent, Daniel Geottlich
Graduate Theses & Non-Theses
The effect of coexisting ions on the selectivity of adsorption onto magnetite nanoparticles (MNPs) for various elements in aqueous solutions was investigated. Surrogate solutions of varying concentrations of rare earth elements (REEs), heavy metals, and gangue elements (low commercial value elements or metals) were mixed with MNPs. Selectivity experiments were performed on surrogate samples based on the composition of a REE ore concentrate and a leach liquor from the chlorinated products of the roasted REE ore concentrate. Adsorption efficiency of magnetite was determined by measuring ion concentration in a sample using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Magnetite is selective …
Electrical Resistance Tomography Measurements In Column Flotation Of Pure Hydrophobic And Hydrophilic Systems,
2024
Montana Technological University
Electrical Resistance Tomography Measurements In Column Flotation Of Pure Hydrophobic And Hydrophilic Systems, Vimeipha Vilayphone
Graduate Theses & Non-Theses
Column flotation was phenomenologically investigated with Electrical Resistance Tomography (ERT) as an uninterrupted instrument to measure gas holdup. Two-phase tests were performed to use the measurements for examining gas dispersion. Results were found to duplicate the findings in a previous thesis. With confidence attained in experimental procedures, three-phase tests were then performed to compare gas holdup with hydrophobic and hydrophilic solids. Hydrophobic solids included talc as well as dolomite with dodecyl amine (DDA) collector. Hydrophilic solids included dolomite as well as talc with carboxymethyl cellulose (CMC) depressant. Variables throughout the research included frother concentration and sparger size. Results showed gas …
Process Intensification For Rare Earth Elements Adsorption By Resonant Vibratory Mixing,
2024
Montana Technological University
Process Intensification For Rare Earth Elements Adsorption By Resonant Vibratory Mixing, Oluwatosin Adebayo, Richard Ladouceur, Zainab Nasrullah
Graduate Theses & Non-Theses
The adsorption capacity for six rare earth elements (Lanthanum, Terbium, Neodymium, Dysprosium, Praseodymium, and Holmium) by biochar produced from hemp feedstock was investigated. An innovative approach to enhancing the adsorption of rare earth elements using biochar was studied and investigates the potential of resonant vibratory mixing (RVM) as a process intensification method compared to conventional mechanical mixing for the adsorption process. Hemp hurds as source of biomass was pyrolyzed to produce biochar at a temperature of 4500C for 60 minutes. The biochar was characterized by FTIR (Fourier Transform Infra-red), SEM (Scanning Electron Microscopy), Surpass 3 Electrokinetic solid surface analyzer, and …
Enhancement Of The Mechanical Behavior Of Nitinol Wire For Vascular Stent Applications By The Addition Of A Polymer Matrix Composite Coating,
2024
Montana Technological University
Enhancement Of The Mechanical Behavior Of Nitinol Wire For Vascular Stent Applications By The Addition Of A Polymer Matrix Composite Coating, Baylie Phillips
Graduate Theses & Non-Theses
Several clinical studies since 2008 have reported stent failure through mechanical means from inadequate strength, fatigue failure, coating failure via delamination and cracking, and pathological failures. Enhancement of the mechanical performance and stability of the polymer coating has the potential to minimize coating failure, aiding in the prevention of the other failure modes. The present study fabricated a polymer matrix composite coating from poly(D,L-lactide-co-glycolic) acid (PLGA) and hydroxyapatite (HA) nanoparticles on nitinol wires. Five weight fractions of HA (1.0, 2.5, 5.0, 7.5, and 10.0 wt.% HA) were studied for their influence on the mechanical performance of nitinol. The coatings were …
