FYPs/Thesis/Journal from Higher Education Institutions in Hong Kong


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Institution Title Type Date Author(s) Abstract Link
HKUST Automated Quality Assessment of Precast Concrete Elements Using 3D Laser Scan Data Thesis 08/2017 Qian WANG Precast concrete elements are popularly adopted in buildings and civil infrastructures like bridges because they provide well-controlled quality, reduced construction time, and less environmental impact. To ensure the performance of complete precast concrete structures, individual precast concrete elements must be cast according to the as-designed blueprints. Any inconsistency between the as-built and as-designed dimensions can result in assembly difficulty or structure failure, causing delay and additional cost. Therefore, it is essential to conduct geometry quality assessment for precast concrete elements before they are shipped to the construction sites. Currently, the quality assessment of precast concrete elements is still relying on manual inspection, which is time-consuming and labor-intensive. Besides, due to tedious work, manual inspection is also error-prone and unreliable. Thus, automated, efficient, and accurate approaches for geometry quality assessment of precast concrete elements are desired. Nowadays, 3D laser scanning has been widely applied to the quality assessment of buildings and civil infrastructures because it can acquire 3D range measurement data at a high speed and high accuracy. However, existing research of laser scanning based quality assessment is mainly focused on simple-geometry elements, such as straight columns and rectangular concrete surfaces. There has been limited research on the quality assessment of precast concrete elements with complex shapes. To tackle the limitations of existing research, this research aims to develop automated, efficient, and accurate techniques for the geometry quality assessment of precast concrete elements using 3D laser scan data. The geometry quality assessment includes dimensional quality assessment, surface flatness and distortion assessment, and rebar position assessment.

For dimensional quality assessment, a dimensional quality assessment technique focusing on the side surfaces of precast concrete panels is developed. This technique aligns the laser scan data with the as-designed building information model (BIM), and extracts the as-built dimensions of the elements. Furthermore, an improved dimensional quality assessment and as-built BIM creation technique is developed to inspect the entire precast concrete element, rather than a surface only, and to automatically create a BIM model for storing the as-built dimensions for better visualization and management. As a supporting study, a novel mixed pixel filter is developed to remove noise data namely mixed pixels from raw laser scan data and to improve the dimension estimation accuracy. The proposed mixed pixel filter formulates the locations of mixed pixels, based on which the optimal threshold value is obtained to classify scan data into mixed pixels and valid points. Another supporting study is to investigate the influence factors for edge line estimation accuracy. Four influence factors are identified and the effect of each factor is analyzed based on numerical simulations. Implications are eventually suggested based on the analysis.

For surface flatness and distortion assessment, the developed technique identifies a few measures for both surface flatness and distortion. These measures are then automatically calculated from the laser scan data of the precast concrete surface for surface quality assessment. Furthermore, an automated rebar position estimation technique is developed to estimate the rebar positions for rebar positioning quality assessment. The technique can recognize individual rebars from the laser scan data of reinforced precast concrete elements and accurately estimate the rebar positions.

This research provides automated approaches for the quality assessment of precast concrete elements, which are able to greatly save the labor cost and time for quality assessment. In addition, the quality of precast concrete structures can be improved due to the faster and more economical quality assessment, thereby further promoting the adoption of precast concrete elements in the construction industry.
HKUST Development of Approaches in Embodied Carbon of Buildings: From Construction Materials to Building Structural Design Thesis 08/2016 Jielong GAN Global warming has been considered as a major environmental challenge nowadays. Among various sources of anthropogenic greenhouse gas (GHG) emissions, the building sector is one of the major contributors to global warming, in which a substantial amount of the GHG emissions are embodied carbon from construction material production and transportation. Embodied carbon can account for 50% of the life cycle GHG emissions in buildings, and this percentage can become more significant for those buildings with shorter service life or higher energy efficiency. Therefore, reducing the embodied carbon in buildings is critically important and can help decrease the life cycle GHG emissions in buildings, thereby pushing human’s living environment towards a sustainable and low carbon future.

This thesis uses two approaches to reducing the embodied carbon in buildings. The first approach focuses on the construction material aspect and aims to reduce the embodied carbon from the manufacturing processes and transportations of construction materials. In this thesis, only the cement-based material (i.e., concrete) and quarried material (i.e., aggregate) are studied using the construction materials approach, as they account for more than 60% of the embodied carbon in a reinforced concrete (RC) building. Methods to the reduction of embodied carbon of aggregate and concrete are proposed, considering the feature of each material. Aggregate is very heavy and generates a large amount of emissions during transportation, therefore the aggregate study presents a mathematical model based on life cycle assessment (LCA) and multi-objective optimization (MOO) in order to plan the optimal amount of aggregate from different supply sources. The model can help stakeholders formulate sustainable material supply strategies that minimize the embodied carbon and material cost. For the concrete study, embodied carbon from concrete mix proportions is more important. Thus, a systematic embodied carbon quantification and mitigation framework is proposed for low carbon concrete mix design. The parameters that significantly affect the mix design and embodied carbon of concrete, namely the compressive strength class, the cement type, the supplementary cementitious materials (SCMs) and the maximum aggregate size, are considered. The proposed framework can be used to identify the low carbon mix design for concrete, and the results serves as a basis for reducing the embodied carbon emissions in buildings.

Another approach to reducing the embodied carbon in buildings considers different kinds of construction materials together, and focuses on building design aspect in order to minimize the total amounts of construction materials and embodied carbon in buildings. While the previous studies in this particular stream concentrated on low-rise building, they overlooked the analysis on high-rise buildings. However, the structural forms, construction materials and component designs in high-rise buildings are different from those in low-rise buildings, which can cause a large variability in the embodied carbon estimates. Therefore, an embodied carbon accounting methodology based on building information modeling (BIM) for high-rise buildings is proposed in this thesis, and relationships between embodied carbon and the critical parameters in high-rise building design are evaluated through BIM and CFD technologies. A 60-story composite core-outrigger building is designed based on the structure of a typical high-rise building in Hong Kong (i.e., Cheung Kong Center), and then used as a reference for the comparative studies. The results of embodied carbon are expressed in terms of carbon dioxide equivalent (CO2-e). The first comparative study focuses on the material procurement strategies. The embodied carbon in the reference building is evaluated with different assumptions for the material manufacturing processes, the amounts of recycled scrap and cement substitutes, and the transportation distance. It is found that structural steel and rebar from traditional blast furnace account for 76% of the embodied carbon in high-rise buildings. If a contractor chooses to use steel from electric arc furnace (with 100% recycled scrap as the feedstock), the embodied carbon of a high-rise building can be decreased by 60%. As for concrete, 10-20% embodied carbon reduction is achieved by using 35% fly ash (FA) or 75% ground granulated blast-furnace slag (GGBS) in mix design. Comparative studies are also carried out to determine the embodied carbon associated with different construction materials, building heights and structural forms. The 60-story composite core-outrigger reference building has a unitary embodied carbon of 557 kg CO2-e/m2 gross floor area (GFA). If the construction material changes to structural steel, the unitary embodied carbon increases to 759 kg CO2-e/m2 GFA, while the value of embodied carbon decreases to 537 kg CO2-e/m2 GFA if RC is used in construction. Core-frame structures are suitable for buildings of 40 stories or below, with the minimum embodied carbon at 525 kg CO2-e/m2 GFA. The optimal height range for core-outrigger structures is from 50-story to 70-story with 530 kg CO2-e/m2 GFA, whereas tubular structures are in the range between 70-story and 90-story at 540 kg CO2-e/m2 GFA. The results serve as a basis for more environmentally friendly building design, thereby improving our built environment towards a sustainable and low carbon future.
HKUST Mapping of BIM and GIS for Interoperable Geospatial Data Management and Analysis for the Built Environment Thesis 08/2015 Yichuan DENG The Building Information Modeling (BIM) domain and the Geographic Information System (GIS) domain share a mutual need for information from each other. Information from GIS can facilitate BIM applications such as site selection and onsite material layout, while models from BIM help generate detailed models in GIS and achieve better utility management. The mapping between the key schemas in the BIM domain and the GIS domain is the most critical step towards interoperability between the two domains. In this research, Industry Foundation Classes (IFC) and City Geography Markup Language (CityGML) were chosen as the key schemas due to their wide applications in the BIM domain and the GIS domain, respectively. A review of previous studies on the integration between BIM and GIS reveals that so far there is no bi-directional mapping considering both geometric and semantic information between IFC and CityGML. Moreover, the transformation between different Levels of Detail (LoDs) in 3D GIS models has not been fully studied. The objective of this research is to develop techniques and tools to allow bi-directional mapping between key schemas in the BIM domain and the GIS domain considering transformation of geometry, semantic information and LoDs. Three use cases based on the integration between BIM and GIS are presented to show how the integration can facilitate problem solving in the architecture, engineering and construction (AEC) industry.

First, the sufficiency of the IFC schema for storing GIS data was evaluated using text analysis techniques and version different analysis. An extension for IFC 4 was developed to store data from CityGML. Then a linguistic-based semi-automatic mapping framework for IFC and CityGML was developed and evaluated, which showed promising results. The bi-directional mapping between IFC and CityGML was developed using instance-based mapping with reference ontology. The mapping framework was compared to previous studies to show its effectiveness.

Second, the transformation between LoDs in 3D GIS models was developed based on the LoD definitions in CityGML. This is a critical step for mapping between BIM and GIS as 3D GIS models are usually represented in different LoDs. An exterior shell extraction algorithm was proposed to facilitate the transformation between LoDs in CityGML. The algorithms of transformation from higher LoDs to lower LoDs were developed and validated using complex and large-scale 3D GIS models.

Finally, three use cases were developed to show how BIM and GIS can facilitate problem solving in the AEC industry. The first use case aimed to build 3D noise maps for urban environments using data from BIM and GIS. The Italian C.N.R. model was used for noise prediction. The highlight of this use case study is that by using BIM and GIS integration, the noise mapping can be performed at room level and the design models can be flexibly updated. The second use case considered construction supply chain management (CSCM) using BIM and GIS integration. The allocation of consolidation centers for multiple construction sites, which is a problem seldom studied by previous literature, is formulated and solved by integrating BIM and GIS. The third case aimed to develop a 3D underground utility management system for urban environments. The system uses modeling functions in BIM as data sources for utility management. Moreover, an algorithm was developed to allow transforming 2D CAD drawings into 3D utility lines.
HKUST Social BIMCloud – A Distributed Cloud-based BIM Framework for Object-based Lifecycle Information Exchange and Supply Chain Integration Thesis 08/2015 Moumita DAS Due to its fragmented and multi-domain architecture, the AEC (architecture, engineering, and construction) industry faces the issues of data transfer efficiency and data consistency while exchanging large BIM files. In this thesis, a cloud based BIM framework, called Social BIMCloud is presented for building design and management of lifecycle activities. Social BIMCloud addresses the issue of data transfer efficiency by reducing the size of the BIM files being exchanged through dynamic splitting and merging mechanisms. Data consistency is also improved by hosting a common integrated BIM model which is updated partially instead of generating a new BIM file for every new change, which usually leads to data duplicity. This collaborative framework, Social BIMCloud is termed “Social” in particular, as it captures and manages the formal and informal social interactions that take place in a construction project. The methodology for capturing and managing social interactions through Social BIMCloud has been demonstrated in this thesis by integrating it with popular BIM software, Autodesk Revit.

Social BIMCloud provides the scope for extending and integrating it with external planning and analysis applications in a plug-and-play manner for lifecycle integration. In this thesis, methodologies and demonstrations have been presented for extending and integrating Social BIMCloud for – (1) construction supply chain (CSC), (2) green building design, and (3) construction site layout planning. For CSC integration, an ontology based web service framework is presented. Ontologies incorporate data semantics in the information exchanged. Therefore, the information exchanging parties, i.e. software applications in the case of automatic information exchange, comprehend the meaning of the information and therefore facilitate smooth flow of heterogeneous information. Two example ontologies have developed by studying the CSC and those ontologies have been used to enrich the data model of Social BIMCloud for accommodating and supporting CSC integration.

Popular energy simulation software were studied to design and extend the schema of Social BIMCloud in order to integrate it with standard simulation and analysis engines through a web service based framework. Social BIMCloud has also been extended for managing construction logistics by integrating it with a construction site layout planning (CSLP) engine. For this integration, the data model of Social BIMCloud has been extended for construction schedule information like activity start date, end date and the relation of each activity with one or more building elements and the vice versa. Finally this thesis discusses the scope of future extensions and improvements on Social BIMCloud for facilitating smooth flow of information in the construction industry.
HKUST Study on Legal Aspects of BIM Projects Report 06/2020 Ka Cheong TANG
Tsz Yin CHOW
Building Information Modeling (BIM) is an emerging technology applied in Architecture, Engineering and Construction (AEC) industry. With the increase in the BIM application, some legal uncertainties have appeared and led to a high risk in legal aspects when adopting BIM in design and construction projects. It is vital that BIM users should be aware of the potential legal issues and develop suitable legal documents and contracts to prevent these issues from occurring. Within this context, a critical review on different cases associated with BIM is carried out in order to provide an overview of potential legal issues. Model copyright, right of BIM common data environment control and responsible control were discussed. Furthermore, three protocols and guidelines commissioned by the United Kingdom, the United States and Singapore are compared and analyzed. BIM Protocol published by Construction Industry Council of the United Kingdom is suggested as the most comprehensive and structured protocol in the analysis. Recommendations on the aspects of BIM cyber security, practical completion and contractors’ perspective are made to Hong Kong AEC professional institutes to commission a suitable and comprehensive protocol for the local industry. N.A.
HKUST Study on BIM Project Execution Plan and BIM Uses in Comparison with PMBOK Report 06/2020 Ka Wing Ngan
Project successful strongly relies on PMBOK. Besides that, BIM is important because it is a powerful tool in delivery of BIM-based project. To implement BIM, BIM uses are defined based on project goals. To effective implement BIM as planned, BIM project execution plan (PXP) is necessary to control BIM. In the first section, this paper compares supporting infrastructure from BIM project execution plan (PXP) to PMBOK to find out the relationship. The categories of supporting infrastructure are BIM PXP overview, project information, key project contacts, project goals / BIM uses, organizational roles / staffing, BIM process design, BIM information exchanges, BIM and facility data requirement, collaboration procedures, quality control, technological infrastructure needs, model structure, project deliverables and delivery strategy / contract whereas PMBOK are integration, scope, time, cost, quality, human resources, communication, risk, procurement and stakeholder management. From the investigation, it is found that risk and cost management is not obviously applied from the categories of supporting infrastructure. In the second section, this paper investigate the relationship of various BIM uses in terms of PMBOK. The considerable BIM uses are design authoring, design review, 3D coordination, cost estimation, phase planning (4D Modelling), digital fabrication and site utilization planning. It is also found that scope, communication and human resources management is not obviously applied from the selected BIM uses. In the third section, we recommend that for BIM PXP additional section including project cost management and BIM risk management should be included; and for BIM uses attention should be paid in drafting BIM PXP to support BIM uses and other BIM uses maybe considered. Manager may benefit from the relationship developed and recommendation in BIM implementation. N.A.