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Kong Q.,University of Houston | Feng Q.,China Earthquake Administration | Feng Q.,Wuhan Institute of Earthquake Engineering | Song G.,Dalian University of Technology
International Journal of Smart and Nano Materials | Year: 2015

Liquid migrating into existing concrete cracks is a serious problem for the reliability of concrete structures and can sometimes induce full concrete structural failures. In this paper, the authors present recent research on water presence detection in concrete cracks using piezoceramic-based smart aggregate (SA) transducers. The active sensing approach, in which one piezoceramic transducer is used to generate stress waves and others are used to detect the stress wave responses, is adopted in this research. Cracks formed in concrete structures act as stress reliefs, which attenuate the energy of the signals received by the SAs. In case of a crack being filled with liquid, which changes the wave impedance, the piezoceramic transducers will report higher received energy levels. A wavelet packet-based approach is developed to provide calculated energy values of the received signal. These different values can help detect the liquid presence in a concrete crack. A concrete beam specimen with three embedded SAs was fabricated and tested. Experimental results verified that the SA-based active sensing approach can detect a concrete crack and further detect the liquid presence in the concrete crack. © 2015 The Author(s). Published by Taylor & Francis. Source

Cheng L.,Wuhan University | Cheng L.,Wuhan Institute of Geologyand Mineral Resources | Chen X.,Wuhan Institute of Geologyand Mineral Resources | Zhang B.,Wuhan Institute of Geologyand Mineral Resources | Cai Y.,Wuhan Institute of Earthquake Engineering
Acta Geologica Sinica | Year: 2011

The skul1 of Anshunsaurus huangnihensis Cheng, 2007, especially the skul1 roof, is described in detai1 in this paper. Compared to other genera and species of Askeptosauroidea, Anshunsaurus huangnihensis has some important transitiona1 characters from Askepiosaurus iialicus to Anshunsaurus huangguoshuensis: the rostra1 length related to the skull length between Askepiosaurus iialicus and Anshunsaurus huangguoshuensis; the postfrontal existing but distinctly reduced; the posterolatera1 process relatedly short and overlapping the parietal. The phylogenetic analysis weakly supports the evolutiona1 progress from Anshunsaurus huangnihensis to Anshunsaurus huangguoshuensis. The skeleta1 ratios indicated that the node among the Askeptosauridae ingroup. The evolutional direction of Askeptosauridae should be from Askepiosaurus iialicus to Anshunsaurus huangguoshuensis. The skeleta1 ratios indicated that the evolutiona1 progress is Askepiosaurus italicus -Anshunsaurus huangnihensis -Anshunsaurus huangguoshuensis. In biogeography provinces, the Askeptosauroidea taxa from south China have a close relationship with those from western Tethys; however, Xinpusaurus from the Late Triassic is more related to those from the eastern Pacific. Source

Cheng L.,Wuhan University | Cheng L.,Wuhan Institute of Geology and Mineral Resources | Chen X.,Wuhan Institute of Geology and Mineral Resources | Zeng X.,Wuhan Institute of Geology and Mineral Resources | Cai Y.,Wuhan Institute of Earthquake Engineering
Journal of Earth Science | Year: 2012

A new eosauropterygian, Largocephalosaurus polycarpon gen. et sp. nov., was described based on a skeleton from the Middle Triassic of Luoping (Chinese source), Yunnan (Chinese source) Province, southwestern China. The new taxon is characterized by a big skull, paired frontal, laterally expanded upper temporal fossa, anterior process of squamosal entering orbit, robust teeth with basally expanded crown and blunt tip, short cervical region, distinctly elongated transverse process of the dorsal vertebrae, short and broad dorsal ribs, stout gastralia, scapula with distinctly posterodorsally extending blade, distinctly robust humerus, eleven carpal ossifications, and a manual fomula of 2-3-4-5-5. A phylogenetic analysis suggests that Largocephalosaurus is the basal-most member of a clade including Wumengosaurus, European pachypleurosaurs, and Nothosauroidea. © 2012 China University of Geosciences and Springer-Verlag Berlin Heidelberg. Source

Li H.,China Earthquake Administration | Li H.,Wuhan Institute of Earthquake Engineering | Qin X.,China Earthquake Administration
Journal of Earthquake Engineering and Engineering Vibration | Year: 2010

In this paper, 3225 strong ground motion records from 128 earthquakes are used to calculate the ratios of the vertical to horizontal acceleration response spectra ( V/H). The records are divided into groups according to site condition, epicentral distance, magnitude and focal mechanism. This study focuses on the relationship between V/ H and these factors. The results show that : (1) the harder the site is, the larger the V/H in long-period range becomes , and the V/H in short-period range is opposite. (2) The greater the magnitude is, the higher the V/H in long-period range becomes, but the V/H in short period is not impressible. (3) The V/H in short period decreases as epicentral distance increases. (4) For great magnitude (M >7) , the V/H in long-period range reduces as the epicentral distance increases. However, for great-moderate earthquakes (M <7) , the ratio increases with the epicentral distance in near-field, and it reduces as the epicentral distance increases in far-field. (5) The V/H is also related to focal mechanism. Source

Zhang X.,Chongqing Jiaotong University | Zhang Y.,Institute of Seismology | Zhang Y.,Wuhan Institute of Earthquake Engineering
Wuhan Ligong Daxue Xuebao (Jiaotong Kexue Yu Gongcheng Ban)/Journal of Wuhan University of Technology (Transportation Science and Engineering) | Year: 2012

Steel truss carriage, which was used as the transfer equipment of heavy cargoes for sloping wharves, had different stress state, because of various handling technology. According to three types of handling technology for Xiangjiaba heavy cargo wharf, three types of working conditions were defined. The third condition was considered the most unfavorable, after the stress and deformation calculation. Through the comparison analysis of setting stiffening plates or not, the conclusion was drawn that the plates were effective on developing the holistic structure rigidity, reducing stress, and controlling deformation. The optimal program was put forward that the stiffening plates should be arranged alternately. The optimal model and computation analysis showed that the alternate arrangement of the plates meet the requirement of the safety and economy. The stress and deformation were under the allowable value of standard code. The optimal program was proved feasible. Source

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