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Effect of Stirrup Corrosion and Fire on Shear Behavior of Reinforced Concrete Beams
Jialiang Liu,Jijun Miao,Guangzhong Ba,Jiangzhuang Xiao,Dongshuai Hou 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.9
This article presents an investigation on corrosion damage effects on the shear bearing capacity of reinforced concrete (RC) beams after a fire. Accelerated corrosion tests were conducted using four RC beams designed with corrosion crack widths ranging from 0.1 mm to 0.3 mm to simulate an aggressive corrosion-prone environment. One control beam (B1) did not undergo accelerated corrosion. The fire test was conducted separately on each beam for two hours to explore how the different widths of corrosive cracks affect heat propagation at elevated fire-induced temperatures. A residual capacity test determined the effects of corrosion on the beams’ residual shear strength after a fire. The experimental results showed that corrosion cracks accelerate the heat propagation in concrete during a fire; moreover, the post-fire residual shear strength for corroded RC beams slightly decreased with an increasing degree of corrosion on the stirrups. The authors also developed a corresponding simplified calculating method to determine residual shear strength, which showed shear design provisions that could improve some existing codes.
Calculation of Thermal Fields of Cracked Concrete at Elevated Temperatures
Yanchun Liu,Jijun Miao,Jialiang Liu,Guangzhong Ba,Caiwei Liu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.1
This paper analyzes the effects of cracking on the thermal field of concrete at elevated temperatures. In four concrete specimens with pre-made cracks, fire tests were performed. Then finite element analysis and theoretical analysis were conducted, which have indicated that heat conduction was the primary source of heat transfer in cracked concrete. At last mathematical software MATLAB was used to calculate the temperatures distributions of a simplified model based on theoretical analysis, which were compared with the test results. The results show that as the thermal diffusion of air is far greater than that of concrete, there is an increase in the thermal propagation through the cracked regions in comparison with undamaged regions, and the temperatures increase with the increase of cracks’ widths. The temperature of concrete farther away from a crack was less affected because concrete has a lower thermal diffusion coefficient. The water content of concrete has an impact on the temperature distributions, which should be considered at the early stage of fire when determining the concrete temperature distributions.
Linya Liu,Zhiyuan Zuo,Qinyue Zhou,Jialiang Qin,Quanmin Liu 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.4
CA mortar layer disengagement will give rise to the overall structural changes of the track and variation in the vibration form of the ballastless track. By establishing a vehicle-track-viaduct coupling analysis and calculation model, it is possible to analyze the CRTS-I type track structure vibration response while the track slab is disengaging with the power flow evaluation method, to compare the two disengaging types, namely partial contact loss at one edge beneath track slab and partial contact loss at midpoint beneath track slab. It can also study how the length of disengaging influences the track structures vibration power. It is showed that when the partial contact loss beneath track slab, and the relative vibration energy level between the rail and the track slab increases significantly within [10, 200]Hz with the same disengaging length, the partial contact loss at one edge beneath track slab has more prominent influence on the vibration power than the partial contact loss at midpoint beneath track slab. With the increase of disengaging length, the relative vibration energy level of the track slab grows sharply, but it will change significantly when it reaches 1.56 m. Little effect will be caused by the relative vibration energy level of the viaduct. The partial contact loss beneath the track slab will cause more power distribution and transmission between the trail and track slab, and will then affect the service life of the rail and track slab.
Xu Zhiqiang,He Jialiang,Liu Tong,Li Haidong 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.1
In the context of triple play Ominimedia is not just the simple combination of various media, but the aggregation of all media with different features, communication power and influences,and the interaction and mutual fusion among media of different forms and functions. This paper, based on the development trend of triple play, focused on the theme of Ominimedia, studied the traditional media development strategies to Ominimedia and analyzed in detail the strategies of cloud, tube, end and content aggregation. At the same time it explored the strategies for Ominimedia core competitive strength improvement from multiple dimensions of 3D media, communication channel, AirSharing and brand operation with the expectation of offering references to Ominimedia globalization in the context of triple play.
Liu Yongliang,Li Lingzhi,Yang Jialiang,Huang Hongliang,Song Wei 한국유전학회 2023 Genes & Genomics Vol.45 No.8
Background The Antarctic krill, Euphausia superba (E. superba), is a key organism in the Antarctic marine ecosystem and has been widely studied. However, there is a lack of transcriptome data focusing on temperature responses. Methods In this study, we performed transcriptome sequencing of E. superba samples exposed to three different temperatures: −1.19 °C (low temperature, LT), − 0.37 °C (medium temperature, MT), and 3 °C (high temperature, HT). Results Illumina sequencing generated 772,109,224 clean reads from the three temperature groups. In total, 1,623, 142, and 842 genes were differentially expressed in MT versus LT, HT versus LT, and HT versus MT, respectively. Moreover, Kyoto Encyclopedia of Genes and Genomes analysis revealed that these differentially expressed genes were mainly involved in the Hippo signaling pathway, MAPK signaling pathway, and Toll−like receptor signaling pathway. Quantitative reverse-transcription PCR revealed that ESG037073 expression was significantly upregulated in the MT group compared with the LT group, and ESG037998 expression was significantly higher in the HT group than in the LT group. Conclusions This is the first transcriptome analysis of E. superba exposed to three different temperatures. Our results provide valuable resources for further studies on the molecular mechanisms underlying temperature adaptation in E. superba.
Structural noise mitigation for viaduct box girder using acoustic modal contribution analysis
Liu Linya,Jialiang Qin,Yun-Lai Zhou,Rui Xi,Siyuan Peng 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.4
In high-speed railway (HSR) system, the structure-borne noise inside viaduct at low frequency has been extensively investigated for its mitigation as a research hotspot owing to its harm to the nearby residents. This study proposed a novel acoustic optimization method for declining the structure-borne noise in viaduct-like structures by separating the acoustic contribution of each structural component in the measured acoustic field. The structural vibration and related acoustic sourcing, propagation, and radiation characteristics for the viaduct box girder under passing vehicle loading are studied by incorporating Finite Element Method (FEM) with Modal Acoustic Vector (MAV) analysis. Based on the Modal Acoustic Transfer Vector (MATV), the structural vibration mode that contributes maximum to the structure-borne noise shall be hereinafter filtered for the acoustic radiation. With vibration mode shapes, the locations of maximum amplitudes for being ribbed to mitigate the structure-borne noise are then obtained, and the structure-borne noise mitigation performance shall be eventually analyzed regarding to the ribbing conduction. The results demonstrate that the structural vibration and structure-borne noise of the viaduct box girder mainly occupy both in the range within 100 Hz, and the dominant frequency bands both are [31.5, 80] Hz. The peak frequency for the structureborne noise of the viaduct box girder is mainly caused by 16th and 62th vibration modes; these two mode shapes mainly reflect the local vibration of the wing plate and top plate. By introducing web plate at the maximum amplitude of main mode shapes that contribute most to the acoustic modal contribution factors, the acoustic pressure peaks at the field-testing points are hereinafter obviously declined, this implies that the structure-borne noise mitigation performance is relatively promising for the viaduct.
Optimal Power Flow of DC-Grid Based on Improved PSO Algorithm
Liu, Xianzheng,Wang, Xingcheng,Wen, Jialiang The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.8 No.1
Voltage sourced converter (VSC) based direct-current (DC) grid has the ability to control power flow flexibly and securely, thus it has become one of the most valid approaches in aspect of large-scale renewable power generation, oceanic island power supply and new urban grid construction. To solve the optimal power flow (OPF) problem in DC grid, an adaptive particle swarm optimization (PSO) algorithm based on fuzzy control theory is proposed in this paper, and the optimal operation considering both power loss and voltage quality is realized. Firstly, the fuzzy membership curve is used to transform two objectives into one, the fitness value of latest step is introduced as input of fuzzy controller to adjust the controlling parameters of PSO dynamically. The proposed strategy was applied in solving the power flow issue in six terminals DC grid model, and corresponding results are presented to verify the effectiveness and feasibility of proposed algorithm.