Pub Date : 2018-04-03DOI: 10.1080/1023697X.2018.1462105
J. Kwan, Harris W K Lam, C. Ng, N. Lam, S. Chan, Jack Yiu, J. Cheuk
ABSTRACT The Geotechnical Engineering Office (GEO) has been steering technical development work to facilitate enhancement in natural terrain landslide risk management in Hong Kong. Collaborations between GEO, the academia from both local and overseas institutes and geotechnical professions have been initiated in recent years to carry out studies on various aspects, including the development of design methodologies for debris-resisting barriers, the investigation of debris impact mechanics and debris–barrier interaction as well as the improvement of detailing of debris-resisting barriers. The concerted efforts have put Hong Kong in a leading position amongst other countries in the area of combating landslide risk. Many of the studies have brought about significant impacts to the engineering practice in many different regions, and have been made reference with by practitioners worldwide in establishing directions of technical development work on the subject. This paper presents the technical advances in natural terrain landslide risk mitigation measures in Hong Kong. It covers a wide spectrum of innovative studies jointly carried out by the GEO and various experts in respect of advanced numerical modelling, laboratory flume testing, centrifuge modelling and large-scale physical modelling, etc. These studies shed light on the potential of rationalising the present barrier design approaches.
{"title":"Recent technical advancement in natural terrain landslide risk mitigation measures in Hong Kong","authors":"J. Kwan, Harris W K Lam, C. Ng, N. Lam, S. Chan, Jack Yiu, J. Cheuk","doi":"10.1080/1023697X.2018.1462105","DOIUrl":"https://doi.org/10.1080/1023697X.2018.1462105","url":null,"abstract":"ABSTRACT The Geotechnical Engineering Office (GEO) has been steering technical development work to facilitate enhancement in natural terrain landslide risk management in Hong Kong. Collaborations between GEO, the academia from both local and overseas institutes and geotechnical professions have been initiated in recent years to carry out studies on various aspects, including the development of design methodologies for debris-resisting barriers, the investigation of debris impact mechanics and debris–barrier interaction as well as the improvement of detailing of debris-resisting barriers. The concerted efforts have put Hong Kong in a leading position amongst other countries in the area of combating landslide risk. Many of the studies have brought about significant impacts to the engineering practice in many different regions, and have been made reference with by practitioners worldwide in establishing directions of technical development work on the subject. This paper presents the technical advances in natural terrain landslide risk mitigation measures in Hong Kong. It covers a wide spectrum of innovative studies jointly carried out by the GEO and various experts in respect of advanced numerical modelling, laboratory flume testing, centrifuge modelling and large-scale physical modelling, etc. These studies shed light on the potential of rationalising the present barrier design approaches.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"25 1","pages":"101 - 90"},"PeriodicalIF":0.0,"publicationDate":"2018-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1023697X.2018.1462105","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44812620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-03DOI: 10.1080/1023697X.2018.1482593
T. Länsivaara
Landslides and debris flows pose a serious risk to human lives and the built environment in many parts of the world. In Hong Kong alone, an average of around 320 landslides occurred each year from 1945 to 2000, with significant loss of life during the decade 1970–1980. Increasing population has pushed human habitation more and more into potential hazard areas. Even in less densely populated areas, landslides and debris flows may endanger infrastructure networks vital to the community. Increasing precipitation due to climate change is likely to accelerate the occurrence of landslides. Although slope stability analysis is one of the oldest disciplines in geotechnical engineering, there is an increasing demand for new research to better understand the core fundamentals of landslide and debris flow failures, so that we can more accurately predict them in today’s changing climate conditions and are able to design more robust hazard mitigation measures. I am honoured and delighted to introduce five high-quality papers and one technical note on this subject to the readers of the HKIE Transactions theme issue on “Landslides and Debris Flow – Theory and Design, Mitigation, Stabilisation and Monitoring”. The first paper by Cheung et al. discusses the use of advanced numerical analysis to model debris flows and barrier interaction. The analyses include landslide debris mobility, the structural analysis of flexible barriers, and coupled analysis of debris impact on a flexible barrier. Verification of the numerical models has been carried out against actual landslides and impact tests with good success. The article by Kwan et al. presents a very helpful summary of the many research studies concerning technical advancements in the design of both rigid and flexible barriers. The reader can pick up helpful studies, for example, on the performance of cushioning materials for reducing dynamic impact on rigid barriers, or the important aspect of serviceability of flexible barriers when a stream crosses the barrier. Lo et al. present the results of an interesting case study of a large-scale failure that occurred following an intense storm on 21 May 2016. The investigations included detailed engineering geological mapping, ground investigation and analyses to diagnose the probable causes of failure and the likelihood of further large-scale instability. The landslide occurred in difficult mountainous terrain, which presented a major challenge for the investigators. From the many important conclusions of the paper, I would like to mention that the failurewas triggered by rain-induced cleft water pressure and that a three-dimensional slope stability assessment was needed for the complex geometry. Sze et al. introduce a new type of flexible barrier in which the shape of the valley is better accounted for, resulting in more favourable geometry and greater structural effectiveness. The design and analysis of such valley-shaped barriers are presented using a state-ofthe-art
{"title":"Foreword","authors":"T. Länsivaara","doi":"10.1080/1023697X.2018.1482593","DOIUrl":"https://doi.org/10.1080/1023697X.2018.1482593","url":null,"abstract":"Landslides and debris flows pose a serious risk to human lives and the built environment in many parts of the world. In Hong Kong alone, an average of around 320 landslides occurred each year from 1945 to 2000, with significant loss of life during the decade 1970–1980. Increasing population has pushed human habitation more and more into potential hazard areas. Even in less densely populated areas, landslides and debris flows may endanger infrastructure networks vital to the community. Increasing precipitation due to climate change is likely to accelerate the occurrence of landslides. Although slope stability analysis is one of the oldest disciplines in geotechnical engineering, there is an increasing demand for new research to better understand the core fundamentals of landslide and debris flow failures, so that we can more accurately predict them in today’s changing climate conditions and are able to design more robust hazard mitigation measures. I am honoured and delighted to introduce five high-quality papers and one technical note on this subject to the readers of the HKIE Transactions theme issue on “Landslides and Debris Flow – Theory and Design, Mitigation, Stabilisation and Monitoring”. The first paper by Cheung et al. discusses the use of advanced numerical analysis to model debris flows and barrier interaction. The analyses include landslide debris mobility, the structural analysis of flexible barriers, and coupled analysis of debris impact on a flexible barrier. Verification of the numerical models has been carried out against actual landslides and impact tests with good success. The article by Kwan et al. presents a very helpful summary of the many research studies concerning technical advancements in the design of both rigid and flexible barriers. The reader can pick up helpful studies, for example, on the performance of cushioning materials for reducing dynamic impact on rigid barriers, or the important aspect of serviceability of flexible barriers when a stream crosses the barrier. Lo et al. present the results of an interesting case study of a large-scale failure that occurred following an intense storm on 21 May 2016. The investigations included detailed engineering geological mapping, ground investigation and analyses to diagnose the probable causes of failure and the likelihood of further large-scale instability. The landslide occurred in difficult mountainous terrain, which presented a major challenge for the investigators. From the many important conclusions of the paper, I would like to mention that the failurewas triggered by rain-induced cleft water pressure and that a three-dimensional slope stability assessment was needed for the complex geometry. Sze et al. introduce a new type of flexible barrier in which the shape of the valley is better accounted for, resulting in more favourable geometry and greater structural effectiveness. The design and analysis of such valley-shaped barriers are presented using a state-ofthe-art","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"25 1","pages":"75 - 75"},"PeriodicalIF":0.0,"publicationDate":"2018-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1023697X.2018.1482593","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47612295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-03DOI: 10.1080/1023697X.2018.1462104
A. L. Yifru, E Laache, H Norem, S. Nordal, V. Thakur
ABSTRACT Debris-flows are forms of landslides in mountainous regions that can potentially cause significant damage. Structural countermeasures to mitigate an entire debris-flow may become unrealistically massive and expensive. If the flow cannot be stopped completely, one may alternatively consider reducing the impact and velocity of the flow using energy dissipating structures. A debris-flow screen is such a countermeasure designed to dissipate energy. A screen is made by parallel grids, with some gaps, placed in the direction of the debris-flow on an elevated foundation. This structure acts as a filter for separating water from the saturated debris-flow to reduce its flow energy. This paper presents a laboratory model test investigating the effect of the screen with length (0.5 m and 1.0 m) and opening width (2 mm, 4 mm and 6 mm) in dissipating the debris-flow energy. The effectiveness of the screens was determined in terms of reductions in the run-out distance and the flow velocity. The importance of the screen length and the opening width is demonstrated. A hypothesis that the optimum opening size should be close to of the solid material seems to be validated. The application of the laboratory observations to the field is indicated based on the energy line and scaling principles.
{"title":"Laboratory investigation of performance of a screen type debris-flow countermeasure","authors":"A. L. Yifru, E Laache, H Norem, S. Nordal, V. Thakur","doi":"10.1080/1023697X.2018.1462104","DOIUrl":"https://doi.org/10.1080/1023697X.2018.1462104","url":null,"abstract":"ABSTRACT Debris-flows are forms of landslides in mountainous regions that can potentially cause significant damage. Structural countermeasures to mitigate an entire debris-flow may become unrealistically massive and expensive. If the flow cannot be stopped completely, one may alternatively consider reducing the impact and velocity of the flow using energy dissipating structures. A debris-flow screen is such a countermeasure designed to dissipate energy. A screen is made by parallel grids, with some gaps, placed in the direction of the debris-flow on an elevated foundation. This structure acts as a filter for separating water from the saturated debris-flow to reduce its flow energy. This paper presents a laboratory model test investigating the effect of the screen with length (0.5 m and 1.0 m) and opening width (2 mm, 4 mm and 6 mm) in dissipating the debris-flow energy. The effectiveness of the screens was determined in terms of reductions in the run-out distance and the flow velocity. The importance of the screen length and the opening width is demonstrated. A hypothesis that the optimum opening size should be close to of the solid material seems to be validated. The application of the laboratory observations to the field is indicated based on the energy line and scaling principles.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"25 1","pages":"129 - 144"},"PeriodicalIF":0.0,"publicationDate":"2018-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1023697X.2018.1462104","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46693595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-01-02DOI: 10.1080/1023697X.2017.1406827
Anthony Ma, Susana X Wu
ABSTRACT A novel three-step zero effluent discharge process was developed through a two-year research study. After completing the laboratory studies, a pilot system (50 kg/day) was built to prove the design concept. It comprised three steps: pretreatment, food waste decomposition and biogas production. Patented pretreatment was developed to treat wet and sticky Asian food waste. Through this machine, organic matter could be automatically separated from non-biodegradable matter and become fine slurry. Two bioreactors were used to cultivate two distinct types of microbial population. In the decomposition bioreactor, complex organics were broken down into three types of reusable products: floatable oil, a nutrient solution of simple organic acids and a protein-rich solid residue. The floatable oil could be sold as raw material for biodiesel, while the solid residue could be dried to produce eco fish feed. The nutrient solution was fed to the second bioreactor to produce biogas. The hydraulic retention time (HRT) of the two bioreactors were two to three days and seven to eight days, respectively. Wastewater coming out of the second bioreactor was recycled back to the pretreatment so that no wastewater was discharged. The developed process can be employed in decentralised systems to convert food waste into high market value products.
{"title":"Food waste total recycling system – a novel zero effluent discharge process for converting food waste into three high market value products","authors":"Anthony Ma, Susana X Wu","doi":"10.1080/1023697X.2017.1406827","DOIUrl":"https://doi.org/10.1080/1023697X.2017.1406827","url":null,"abstract":"ABSTRACT A novel three-step zero effluent discharge process was developed through a two-year research study. After completing the laboratory studies, a pilot system (50 kg/day) was built to prove the design concept. It comprised three steps: pretreatment, food waste decomposition and biogas production. Patented pretreatment was developed to treat wet and sticky Asian food waste. Through this machine, organic matter could be automatically separated from non-biodegradable matter and become fine slurry. Two bioreactors were used to cultivate two distinct types of microbial population. In the decomposition bioreactor, complex organics were broken down into three types of reusable products: floatable oil, a nutrient solution of simple organic acids and a protein-rich solid residue. The floatable oil could be sold as raw material for biodiesel, while the solid residue could be dried to produce eco fish feed. The nutrient solution was fed to the second bioreactor to produce biogas. The hydraulic retention time (HRT) of the two bioreactors were two to three days and seven to eight days, respectively. Wastewater coming out of the second bioreactor was recycled back to the pretreatment so that no wastewater was discharged. The developed process can be employed in decentralised systems to convert food waste into high market value products.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"25 1","pages":"17 - 28"},"PeriodicalIF":0.0,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1023697X.2017.1406827","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48542578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-01-02DOI: 10.1080/1023697X.2017.1413958
Wilson W S Mok, Victor K Lo, Germaine T M Chau, Louis Y M Lau
ABSTRACT In this paper, the design and construction of 1.75 km of 1200 mm, 1500 mm and 2800 mm diameter concrete sleeve pipelines, using slurry operated tunnel boring machines (TBM), for installation of district cooling system (DCS) pipelines, in highly variable ground conditions in the Kowloon Bay area are discussed. This was the first time that TBM pipejacking has been used in Hong Kong to construct pipelines below the seabed. The construction techniques for working pits to suit site constraints are also discussed. Hand-dug tunnels, constructed with hand-mining shield and horizontal pipe-piles, for DCS pipeline installation, due to the constraints by utilities and interfacing contracts, are highlighted.
{"title":"Trenchless construction of Phase IIIA district cooling system (DCS) by TBM pipejacking and hand-dug tunnelling on Kai Tak Development: part I – design and construction considerations","authors":"Wilson W S Mok, Victor K Lo, Germaine T M Chau, Louis Y M Lau","doi":"10.1080/1023697X.2017.1413958","DOIUrl":"https://doi.org/10.1080/1023697X.2017.1413958","url":null,"abstract":"ABSTRACT In this paper, the design and construction of 1.75 km of 1200 mm, 1500 mm and 2800 mm diameter concrete sleeve pipelines, using slurry operated tunnel boring machines (TBM), for installation of district cooling system (DCS) pipelines, in highly variable ground conditions in the Kowloon Bay area are discussed. This was the first time that TBM pipejacking has been used in Hong Kong to construct pipelines below the seabed. The construction techniques for working pits to suit site constraints are also discussed. Hand-dug tunnels, constructed with hand-mining shield and horizontal pipe-piles, for DCS pipeline installation, due to the constraints by utilities and interfacing contracts, are highlighted.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"25 1","pages":"56 - 66"},"PeriodicalIF":0.0,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1023697X.2017.1413958","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47318819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-01-02DOI: 10.1080/1023697X.2017.1409663
Y. P. Liu, Sinno Jialin Pan, Simon W K Leung, Sharon Lai-Fung Chan
ABSTRACT Long-span roofs are widely used worldwide as they provide large internal spaces without obstructions like columns. In designing long-span roofs, the traditional design method faces many difficulties, such as uncertainty in buckling effective length. The advanced second-order direct analysis (SODA) method for design shows and has many advantages for structural safety and cost saving. In this paper, the SODA considering P-Δ and P-δ effects as well as initial imperfections is proposed for designing of long-span roofs and the assumption of effective length is no longer required. The application of this concept of SODA to the design of practical structures appears to be new and unique, especially on the aspects of design at the construction stages. Key considerations for the construction of long-span structures by SODA are first reported. The planning of the lifting procedure, temporary support system (TSS) and off-loading sequences for load transfer from a TSS to permanent structure is guided by SODA such that an economic design and safe construction can be achieved. A constructed long-span single-layer roof structure in Macau is used to demonstrate the validity, practicality, accuracy and reliability of the proposed method and is taken as an example of successful joint work for advanced design by academicians and engineers in practice.
{"title":"Design and construction of long-span single-layer dome structures by direct analysis","authors":"Y. P. Liu, Sinno Jialin Pan, Simon W K Leung, Sharon Lai-Fung Chan","doi":"10.1080/1023697X.2017.1409663","DOIUrl":"https://doi.org/10.1080/1023697X.2017.1409663","url":null,"abstract":"ABSTRACT Long-span roofs are widely used worldwide as they provide large internal spaces without obstructions like columns. In designing long-span roofs, the traditional design method faces many difficulties, such as uncertainty in buckling effective length. The advanced second-order direct analysis (SODA) method for design shows and has many advantages for structural safety and cost saving. In this paper, the SODA considering P-Δ and P-δ effects as well as initial imperfections is proposed for designing of long-span roofs and the assumption of effective length is no longer required. The application of this concept of SODA to the design of practical structures appears to be new and unique, especially on the aspects of design at the construction stages. Key considerations for the construction of long-span structures by SODA are first reported. The planning of the lifting procedure, temporary support system (TSS) and off-loading sequences for load transfer from a TSS to permanent structure is guided by SODA such that an economic design and safe construction can be achieved. A constructed long-span single-layer roof structure in Macau is used to demonstrate the validity, practicality, accuracy and reliability of the proposed method and is taken as an example of successful joint work for advanced design by academicians and engineers in practice.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"25 1","pages":"29 - 43"},"PeriodicalIF":0.0,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1023697X.2017.1409663","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47134545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-01-02DOI: 10.1080/1023697X.2017.1409664
Zicheng Wang, Yadong Zhang, Jin Guo, Lina Su
ABSTRACT The outdoor equipment failures of track circuits are usually not easy to be detected. In addition, the location of outdoor equipment failures can cause trouble for on-site maintainers. To solve the problem, this paper proposes a novel method for fault diagnosis of railway track circuits based on multifractal detrended fluctuation analysis (MF-DFA). Firstly, a locomotive signal induced voltage model was established based on the uniform transmission-line theory. The locomotive signal amplitude envelope (LSAE) signals of the track circuit in the normal and fault conditions were solved out. Through this model, the influence mechanism of track circuit faults on the LSAE signals was revealed. On the basis of MF-DFA, the generalised Hurst exponents and multifractal spectra of the LSAE signals were obtained. Then the six-dimensional vectors extracted from the multifractal spectra were used as the fault features. Finally, these features were input to the extreme learning machine (ELM) to identify faults. The fault diagnosis accuracy using the method proposed in this paper reached 94.2949% after k-fold cross validation. The results indicated that MF-DFA had obvious advantages in the application of track circuit fault diagnosis.
{"title":"Application of multifractal detrended fluctuation analysis in fault diagnosis for a railway track circuit","authors":"Zicheng Wang, Yadong Zhang, Jin Guo, Lina Su","doi":"10.1080/1023697X.2017.1409664","DOIUrl":"https://doi.org/10.1080/1023697X.2017.1409664","url":null,"abstract":"ABSTRACT The outdoor equipment failures of track circuits are usually not easy to be detected. In addition, the location of outdoor equipment failures can cause trouble for on-site maintainers. To solve the problem, this paper proposes a novel method for fault diagnosis of railway track circuits based on multifractal detrended fluctuation analysis (MF-DFA). Firstly, a locomotive signal induced voltage model was established based on the uniform transmission-line theory. The locomotive signal amplitude envelope (LSAE) signals of the track circuit in the normal and fault conditions were solved out. Through this model, the influence mechanism of track circuit faults on the LSAE signals was revealed. On the basis of MF-DFA, the generalised Hurst exponents and multifractal spectra of the LSAE signals were obtained. Then the six-dimensional vectors extracted from the multifractal spectra were used as the fault features. Finally, these features were input to the extreme learning machine (ELM) to identify faults. The fault diagnosis accuracy using the method proposed in this paper reached 94.2949% after k-fold cross validation. The results indicated that MF-DFA had obvious advantages in the application of track circuit fault diagnosis.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"25 1","pages":"44 - 55"},"PeriodicalIF":0.0,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1023697X.2017.1409664","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43764398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-01-02DOI: 10.1080/1023697X.2017.1420494
Xiaojing Zhang, Xiaohua Zhang
ABSTRACT Due to the limited influence on traffic, orthotropic steel deck has been more and more widely used. However, the durability of steel deck asphalt pavement is a critical technical issue in the construction of bridges. At the Bus Rapid Transit (BRT) bus station, rutting, swelling and several other distresses were observed shortly after opening to traffic. In order to deal with these distresses, both an emergency repairing method and a long-term rehabilitation approach are proposed and analysed in this technical note. For the emergency measure, a newly-developed polymer material, which has both high-temperature stability and low-temperature flexibility, was applied and no distresses occurred for a long time when the modified self-compacting elastic concrete was used. For the long-term approach, an advanced modified asphalt binder and an improved cost-effective stone matrix asphalt (SMA) mixture with both high-temperature stability and low-temperature flexibility are developed by conducting a series of orthogonal tests in the lab. The findings of this technical note can be used as a reference to deal with similar distresses.
{"title":"Asphalt materials used in treatment of pavement distresses at the BRT bus station","authors":"Xiaojing Zhang, Xiaohua Zhang","doi":"10.1080/1023697X.2017.1420494","DOIUrl":"https://doi.org/10.1080/1023697X.2017.1420494","url":null,"abstract":"ABSTRACT Due to the limited influence on traffic, orthotropic steel deck has been more and more widely used. However, the durability of steel deck asphalt pavement is a critical technical issue in the construction of bridges. At the Bus Rapid Transit (BRT) bus station, rutting, swelling and several other distresses were observed shortly after opening to traffic. In order to deal with these distresses, both an emergency repairing method and a long-term rehabilitation approach are proposed and analysed in this technical note. For the emergency measure, a newly-developed polymer material, which has both high-temperature stability and low-temperature flexibility, was applied and no distresses occurred for a long time when the modified self-compacting elastic concrete was used. For the long-term approach, an advanced modified asphalt binder and an improved cost-effective stone matrix asphalt (SMA) mixture with both high-temperature stability and low-temperature flexibility are developed by conducting a series of orthogonal tests in the lab. The findings of this technical note can be used as a reference to deal with similar distresses.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"25 1","pages":"67 - 73"},"PeriodicalIF":0.0,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1023697X.2017.1420494","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44983934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-01-02DOI: 10.1080/1023697X.2017.1396258
H. Cochrane, Fredrick Leong, Steven So, George K. C. Or, Melvyn Lai
ABSTRACT This paper showcases the green engineering excellence in design, construction and operation of NTT Communications Hong Kong Financial Data Center Tower 2 (FDC2) at No. 6 Chun Kwong Street in Tseung Kwan O Industrial Estate, Hong Kong, and its roadmap in achieving LEED 2009 for Core and Shell Development (LEED-CS 2009) certification to the highest Platinum level. Key environmental issues are discussed with the adopted approach and technologies to avoid, minimise and mitigate environmental impacts. In particular, based on LEED assessment, FDC2 demonstrates the excellence in energy efficiency using server virtualisation to a significant reduction of ∼60% consumption equivalent to ∼510,000,000 kWh per year and greenhouse gas emission equivalent to 357,000 tonnes of CO2. This has attained the maximum 21 Points under LEED-CS 2009 EAc1 Optimise Energy Performance. Notably, FDC2 strives for “Think Sustainability from the Project Start” to reduce energy use, carbon footprint and environmental impacts, with achieving various firsts in Hong Kong and China (according to Green Business Certification Inc. (GBCI)). The sustainable operation of this world class green data centre will continue its pioneered, innovative and excellent environmental performance to play as a role model of sustainable development in the data centre and IT industry.
{"title":"Green engineering of Hong Kong and China's first data centre certified to LEED-CS 2009 Platinum","authors":"H. Cochrane, Fredrick Leong, Steven So, George K. C. Or, Melvyn Lai","doi":"10.1080/1023697X.2017.1396258","DOIUrl":"https://doi.org/10.1080/1023697X.2017.1396258","url":null,"abstract":"ABSTRACT This paper showcases the green engineering excellence in design, construction and operation of NTT Communications Hong Kong Financial Data Center Tower 2 (FDC2) at No. 6 Chun Kwong Street in Tseung Kwan O Industrial Estate, Hong Kong, and its roadmap in achieving LEED 2009 for Core and Shell Development (LEED-CS 2009) certification to the highest Platinum level. Key environmental issues are discussed with the adopted approach and technologies to avoid, minimise and mitigate environmental impacts. In particular, based on LEED assessment, FDC2 demonstrates the excellence in energy efficiency using server virtualisation to a significant reduction of ∼60% consumption equivalent to ∼510,000,000 kWh per year and greenhouse gas emission equivalent to 357,000 tonnes of CO2. This has attained the maximum 21 Points under LEED-CS 2009 EAc1 Optimise Energy Performance. Notably, FDC2 strives for “Think Sustainability from the Project Start” to reduce energy use, carbon footprint and environmental impacts, with achieving various firsts in Hong Kong and China (according to Green Business Certification Inc. (GBCI)). The sustainable operation of this world class green data centre will continue its pioneered, innovative and excellent environmental performance to play as a role model of sustainable development in the data centre and IT industry.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"25 1","pages":"1 - 16"},"PeriodicalIF":0.0,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1023697X.2017.1396258","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43188589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-10-02DOI: 10.1080/1023697X.2017.1375436
V. Gan, C. Chan, K. T. Tse, Jack C. P. Cheng, Irene Lo
ABSTRACT Understanding the impact of material choices and structural forms on the embodied carbon and construction cost in high-rise buildings is important to improve building designs with regard to sustainability. The objective of this study is to investigate the impact of the choice of construction materials and structural forms on the embodied carbon and construction cost of high-rise buildings. The results show that high-rise buildings using structural steel have the highest construction cost at 4575 HK$/m2 and the most embodied carbon at 760 kg CO2-e/m2, respectively. Using reinforced concrete for high-rise buildings reduces 30% of the embodied carbon (to 4194 HK$/m2) and 7% of the construction cost (to 537 kg CO2-e/m2). High-rise buildings using composite materials have the lowest construction cost (3740 HK$/m2), but produce slightly more embodied carbon (557 kg CO2-e/m2) than concrete buildings. For a specific structural form, the construction cost and the embodied carbon as a function of the building height follow concave upward trends, indicating that each structure has a suggested height with relatively lower cost and carbon content, e.g. 50–70 storeys for composite core-outrigger structure at around 3700–3900 HK$/m2. Similarly, the suggested height for composite tube-in-tube structure is 60–80 storeys at 3900–4100 HK$/m2, whereas braced-tube structure has a suggested height of 60–80 storeys at 3500–3600 HK$/m2.
摘要了解材料选择和结构形式对高层建筑内含碳和建筑成本的影响，对于提高建筑设计的可持续性至关重要。本研究的目的是调查建筑材料和结构形式的选择对高层建筑内含碳和建筑成本的影响。结果表明，使用结构钢的高层建筑的建筑成本最高，为4575 港元/平方米，碳含量最高，为760 kg CO2-e/m2。在高层建筑中使用钢筋混凝土可减少30%的内含碳（达到4194 港元/平方米）和建筑成本的7%（至537 kg CO2-e/m2）。使用复合材料的高层建筑的建筑成本最低（3740 港元/平方米），但产生的含碳量略高（557 kg CO2-e/m2）。对于特定的结构形式，建筑成本和内含碳作为建筑高度的函数，呈凹向上的趋势，这表明每个结构都有一个成本和碳含量相对较低的建议高度，例如，复合芯-外伸支腿结构的50–70层，约3700–3900 HK$/m2。同样，复合管中筒结构的建议高度为60-80层，为3900-4100 HK$/m2，而支撑管结构的建议高度为60–80层，为3500–3600 港元/平方米。
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