Time filter

Source Type

Cao H.,HongKong Zhuhai Macao bridge authority
1st CCPS Asia-Pacific Conference on Process Safety 2013, APCPS 2013 | Year: 2013

This paper introduces the integrated HSE (Health, Safety and Environment) management model adopted by the owner of the Hong Kong-Zhuhai-Macao Bridge during its construction, including the preliminary work before this creative adoption, the main content as well as the performance of this model. Considering the satisfying operation status indicated by the monitoring data, the author advocates that the HSE management model being applied in major infrastructure construction. © Copyright (2013) By AIChE. All rights reserved.


Wang Z.-T.,CAS Wuhan Institute of Hydrobiology | Wang Z.-T.,University of Chinese Academy of Sciences | Wang Z.-T.,Hawaii Institute of Marine Biology | Nachtigall P.E.,Hawaii Institute of Marine Biology | And 7 more authors.
PLoS ONE | Year: 2015

A growing demand for sustainable energy has led to an increase in construction of offshore windfarms. Guishan windmill farm will be constructed in the Pearl River Estuary, China, which sustains the world's largest known population of Indo-Pacific humpback dolphins (Sousa chinensis). Dolphin conservation is an urgent issue in this region. By using passive acoustic monitoring, a baseline distribution of data on this species in the Pearl River Estuary during pre-construction period had been collected. Dolphin biosonar detection and its diel, lunar, seasonal and tidal patterns were examined using a Generalized Linear Model. Significant higher echolocation detections at night than during the day, in winter-spring than in summer-autumn, at high tide than at flood tide were recognized. Significant higher echolocation detections during the new moon were recognized at night time. The diel, lunar and seasonal patterns for the echolocation encounter duration also significantly varied. These patterns could be due to the spatial-temporal variability of dolphin prey and illumination conditions. The baseline information will be useful for driving further effective action on the conservation of this species and in facilitating later assessments of the effects of the offshore windfarm on the dolphins by comparing the baseline to post construction and post mitigation efforts. © 2015 Wang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Wang Z.-T.,CAS Wuhan Institute of Hydrobiology | Wang Z.-T.,University of Chinese Academy of Sciences | Wang Z.-T.,Hawaii Institute of Marine Biology | Wang Z.-T.,Duke University | And 9 more authors.
PeerJ | Year: 2016

Background. Knowledge of species-specific vocalization characteristics and their associated active communication space, the effective range over which a communication signal can be detected by a conspecific, is critical for understanding the impacts of underwater acoustic pollution, as well as other threats. Methods. We used a two-dimensional cross-shaped hydrophone array system to record the whistles of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in shallow-water environments of the Pearl River Estuary (PRE) and Beibu Gulf (BG), China. Using hyperbolic position fixing, which exploits time differences of arrival of a signal between pairs of hydrophone receivers, we obtained source location estimates for whistles with good signal-to-noise ratio (SNR≥10 dB) and not polluted by other sounds and back-calculated their apparent source levels (ASL). Combining with the masking levels (including simultaneous noise levels, masking tonal threshold, and the Sousa auditory threshold) and the custom made site-specific sound propagation models, we further estimated their active communication space (ACS). Results. Humpback dolphins produced whistles with average root-mean-square ASL of 138.5±6.8 (mean±standard deviation) and 137.2± 7.0 dB re 1 mPa in PRE (N D33) and BG (N D209), respectively. We found statistically significant differences in ASLs among different whistle contour types. The mean and maximum ACS of whistles were estimated to be 14.7 ± 2.6 (median± quartile deviation) and 17.1±3.5min PRE, and 34.2 ± 9.5 and 43.5 ± 12.2 m in BG. Using just the auditory threshold as the masking level produced the mean and maximum ACSat of 24.3 ± 4.8 and 35.7 ± 4.6 m for PRE, and 60.7 ± 18.1 and 74.3 ± 25.3 m for BG. The small ACSs were due to the high ambient noise level. Significant differences in ACSs were also observed among different whistle contour types. Discussion. Besides shedding some light for evaluating appropriate noise exposure levels and information for the regulation of underwater acoustic pollution, these baseline data can also be used for aiding the passive acoustic monitoring of dolphin populations, defining the boundaries of separate groups in a more biologically meaningful way during field surveys, and guiding the appropriate approach distance for local dolphin-watching boats and research boat during focal group following. © 2016 Wang et al.


Wang Z.,CAS Wuhan Institute of Hydrobiology | Wang Z.,University of Chinese Academy of Sciences | Wang Z.,Hawaii Institute of Marine Biology | Wu Y.,Sun Yat Sen University | And 5 more authors.
PLoS ONE | Year: 2014

Anthropogenic noise in aquatic environments is a worldwide concern due to its potential adverse effects on the environment and aquatic life. The Hongkong-Zhuhai-Macao Bridge is currently under construction in the Pearl River Estuary, a hot spot for the Indo-Pacific humpbacked dolphin (Sousa chinensis) in China. The OCTA-KONG, the world's largest vibration hammer, is being used during this construction project to drive or extract steel shell piles 22 m in diameter. This activity poses a substantial threat to marine mammals, and an environmental assessment is critically needed. The underwater acoustic properties of the OCTA-KONG were analyzed, and the potential impacts of the underwater acoustic energy on Sousa, including auditory masking and physiological impacts, were assessed. The fundamental frequency of the OCTA-KONG vibration ranged from 15 Hz to 16 Hz, and the noise increments were below 20 kHz, with a dominant frequency and energy below 10 kHz. The resulting sounds are most likely detectable by Sousa over distances of up to 3.5 km from the source. Although Sousa clicks do not appear to be adversely affected, Sousa whistles are susceptible to auditory masking, which may negatively impact this species' social life. Therefore, a safety zone with a radius of 500 m is proposed. Although the zero-to-peak source level (SL) of the OCTA-KONG was lower than the physiological damage level, the maximum root-mean-square SL exceeded the cetacean safety exposure level on several occasions. Moreover, the majority of the unweighted cumulative source sound exposure levels (SSELs) and the cetacean auditory weighted cumulative SSELs exceeded the acoustic threshold levels for the onset of temporary threshold shift, a type of potentially recoverable auditory damage resulting from prolonged sound exposure. These findings may aid in the identification and design of appropriate mitigation methods, such as the use of air bubble curtains, "soft start" and "power down" techniques. © 2014 Wang et al.


PubMed | Transport Planning and Research Institute, Hongkong Zhuhai Macao Bridge Authority, Sun Yat Sen University, Japan National Research Institute of Fisheries Engineering and 2 more.
Type: Journal Article | Journal: PloS one | Year: 2015

A growing demand for sustainable energy has led to an increase in construction of offshore windfarms. Guishan windmill farm will be constructed in the Pearl River Estuary, China, which sustains the worlds largest known population of Indo-Pacific humpback dolphins (Sousa chinensis). Dolphin conservation is an urgent issue in this region. By using passive acoustic monitoring, a baseline distribution of data on this species in the Pearl River Estuary during pre-construction period had been collected. Dolphin biosonar detection and its diel, lunar, seasonal and tidal patterns were examined using a Generalized Linear Model. Significant higher echolocation detections at night than during the day, in winter-spring than in summer-autumn, at high tide than at flood tide were recognized. Significant higher echolocation detections during the new moon were recognized at night time. The diel, lunar and seasonal patterns for the echolocation encounter duration also significantly varied. These patterns could be due to the spatial-temporal variability of dolphin prey and illumination conditions. The baseline information will be useful for driving further effective action on the conservation of this species and in facilitating later assessments of the effects of the offshore windfarm on the dolphins by comparing the baseline to post construction and post mitigation efforts.


PubMed | Transport Planning and Research Institute, Hongkong Zhuhai Macao Bridge Authority, Sun Yat Sen University, Qinzhou University and 3 more.
Type: | Journal: PeerJ | Year: 2016

Background. Knowledge of species-specific vocalization characteristics and their associated active communication space, the effective range over which a communication signal can be detected by a conspecific, is critical for understanding the impacts of underwater acoustic pollution, as well as other threats. Methods. We used a two-dimensional cross-shaped hydrophone array system to record the whistles of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in shallow-water environments of the Pearl River Estuary (PRE) and Beibu Gulf (BG), China. Using hyperbolic position fixing, which exploits time differences of arrival of a signal between pairs of hydrophone receivers, we obtained source location estimates for whistles with good signal-to-noise ratio (SNR 10 dB) and not polluted by other sounds and back-calculated their apparent source levels (ASL). Combining with the masking levels (including simultaneous noise levels, masking tonal threshold, and the Sousa auditory threshold) and the custom made site-specific sound propagation models, we further estimated their active communication space (ACS). Results. Humpback dolphins produced whistles with average root-mean-square ASL of 138.5 6.8 (mean standard deviation) and 137.2 7.0 dB re 1 Pa in PRE (N = 33) and BG (N = 209), respectively. We found statistically significant differences in ASLs among different whistle contour types. The mean and maximum ACS of whistles were estimated to be 14.7 2.6 (median quartile deviation) and 17.1 3.5 m in PRE, and 34.2 9.5 and 43.5 12.2 m in BG. Using just the auditory threshold as the masking level produced the mean and maximum ACSat of 24.3 4.8 and 35.7 4.6 m for PRE, and 60.7 18.1 and 74.3 25.3 m for BG. The small ACSs were due to the high ambient noise level. Significant differences in ACSs were also observed among different whistle contour types. Discussion. Besides shedding some light for evaluating appropriate noise exposure levels and information for the regulation of underwater acoustic pollution, these baseline data can also be used for aiding the passive acoustic monitoring of dolphin populations, defining the boundaries of separate groups in a more biologically meaningful way during field surveys, and guiding the appropriate approach distance for local dolphin-watching boats and research boat during focal group following.


PubMed | Transport Planning and Research Institute, University of Chinese Academy of Sciences, Sun Yat Sen University, CAS Wuhan Institute of Hydrobiology and Hongkong Zhuhai Macao Bridge Authority
Type: Journal Article | Journal: PloS one | Year: 2014

Anthropogenic noise in aquatic environments is a worldwide concern due to its potential adverse effects on the environment and aquatic life. The Hongkong-Zhuhai-Macao Bridge is currently under construction in the Pearl River Estuary, a hot spot for the Indo-Pacific humpbacked dolphin (Sousa chinensis) in China. The OCTA-KONG, the worlds largest vibration hammer, is being used during this construction project to drive or extract steel shell piles 22 m in diameter. This activity poses a substantial threat to marine mammals, and an environmental assessment is critically needed. The underwater acoustic properties of the OCTA-KONG were analyzed, and the potential impacts of the underwater acoustic energy on Sousa, including auditory masking and physiological impacts, were assessed. The fundamental frequency of the OCTA-KONG vibration ranged from 15 Hz to 16 Hz, and the noise increments were below 20 kHz, with a dominant frequency and energy below 10 kHz. The resulting sounds are most likely detectable by Sousa over distances of up to 3.5 km from the source. Although Sousa clicks do not appear to be adversely affected, Sousa whistles are susceptible to auditory masking, which may negatively impact this species social life. Therefore, a safety zone with a radius of 500 m is proposed. Although the zero-to-peak source level (SL) of the OCTA-KONG was lower than the physiological damage level, the maximum root-mean-square SL exceeded the cetacean safety exposure level on several occasions. Moreover, the majority of the unweighted cumulative source sound exposure levels (SSELs) and the cetacean auditory weighted cumulative SSELs exceeded the acoustic threshold levels for the onset of temporary threshold shift, a type of potentially recoverable auditory damage resulting from prolonged sound exposure. These findings may aid in the identification and design of appropriate mitigation methods, such as the use of air bubble curtains, soft start and power down techniques.


Su Z.,Hongkong Zhuhai Macao Bridge Authority | He C.,Southwest Jiaotong University
Modern Tunnelling Technology | Year: 2015

The mechanical mechanism of a fabricated shield tunnel segment lining with longitudinal deformation is rather complex, and it is often difficult to determine the values of the longitudinal loads because of the structure/ground interaction. At present, the segment's additional internal forces, joint bolt forces and joint openings cannot be directly calculated by the common longitudinal elastic foundation beam model or the three-dimensional homogeneous shell model. In this paper, based on a longitudinal shell-spring-contact FEM model, the additional 3D internal forces and deformations after the longitudinal deformation of a shield tunnel are analyzed by a forced displacement method. The calculation results indicate that longitudinal deformation of a shield tunnel causes not only additional longitudinal internal forces, but also a certain transverse deformation and additional transverse internal forces; main bending zones and shearing zones occur along the longitudinal direction; concrete stress concentration occurs near the areas with large longitudinal internal bolt forces. © 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved.


Ma N.-J.,South China University of Technology | Wang R.-H.,South China University of Technology | Han Q.,South China University of Technology | Li P.-J.,South China University of Technology | Piao L.,Hongkong Zhuhai Macao Bridge Authority
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2012

Based on energy principle, the local vibration of orthotropic steel bridge decks was studied. The orthotropic steel bridge deck was considered to be a stiffened plate. Both longitudinal stiffeners and transverse diaphragms were considered to be beam elements according to the equivalent principle of mass and rigidity. Besides, the plate was analyzed with classic thin plate theory. The mode shape functions were expressed by the product of two independent beam functions. During the deviation of frequency equation, eccentricity and torsion of stiffeners were considered, as well as the membrane strain energy of the plate. A stiffened plate with three classical boundary conditions was studied. The results show that the method proposed is in good agreement with the software ANSYS. The eccentricity of stiffeners has a significant influence on lower frequencies, while the torsional rigidity of stiffeners has a significant influence on higher frequencies, and the equivalent orthotropic plate method is not appropriate to compute high frequencies.

Loading Hongkong Zhuhai Macao Bridge Authority collaborators
Loading Hongkong Zhuhai Macao Bridge Authority collaborators