Modular and Offsite Construction (MOC) Summit Proceedings
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Steel Beam-Column Joint with Discontinuous Vertical Reinforcing Bars
Get PDFThe authors proposed steel beam-column connections for precast concrete frames in previous studies. The steel-concrete composite frames provided fast assembly time as steels with economy of concrete structures. However, when enough space is not available at column-beam joints steel sections from beams cannot be connected with column brackets. This paper suggests that some vertical reinforcing bars are disconnected at joints by connecting vertical steel reinforcements to steel plates placed above and below column steels to provide load transferring path. Loads from re-bars are transferred to steel plates, column steels and back to steel plates and re-bars below column steels. Re-bars connected to steel plates by bolts at above and below column steel are discontinued at joint to provide spaces for connections between column brackets and beam steels. Extensive experiments were performed to verify load transfer from re-bars to steel plates above joints and steel plates to re-bars below joint. The flexural load bearing capacity of a column with total of 24 vertical re-bars were compared to columns with discontinuous re-bars at joints. The number of discontinuous re-bars at joint used in column specimen was 0 (0.0%), 4 (16.7%), 12 (50.0%), and 20 (83.3%). The numbers in parenthesis are the percentages of discontinuous rebars to the total number of vertical re-bars of control column. Experiments showed how loads from vertical steel reinforcements that were cut off at joints were transferred to steel plate. The test results also demonstrated that a part of flexural capacities were reduced for specimen with discontinuous vertical re-bars. The reduction of 6.0 %, 13.7% and 54.0% of flexural capacities were observed for columns with 4 (16.7%), 12 (50.0%) and 20 (83.3%) discontinuous vertical rebars, respectively. The test results can be used to design vertical reinforcing bars and column joints that can provide space for column brackets to which steel members of beams are connected
Design and Specification Compilation of a Modularized Prefabricated High-rise Steel Frame Structure with Inclined Braces Part I: Integral Structural Design
Get PDFModularized prefabricated steel structures have certain obvious advantages, i.e., rapid construction, industrial-scale production and pro-environmental aspects, and are the main method in industrialization of steel structures. Although applications of these structures have been reported all over the world, in most cases, the steel structural systems are only suitable for low-rise buildings, and their application in high-rise buildings is quite limited. This paper proposes a new type of modularized prefabricated high-rise steel frame structure with inclined braces. Based on the T30 hotel building, the mechanical properties, failure mode, failure mechanism and elastic-plastic development laws are investigated by using the elastic design of a structure under various load conditions, the analysis of the internal force and displacement responses under frequent earthquakes via the response spectrum method and linear time-history analysis, the static elastic-plastic pushover analysis under rare earthquake conditions. According to finite element simulations and testing, elastic and elastic-plastic structural design methods are proposed in this paper. This work provides an important reference for research and design of the same type of modularized prefabricated high-rise steel structures, and the design method has been compiled into design specification
Robotic Assembly System for Steel Structures
Get PDFWorkers are required to stand on dangerous unfinished steel structures to assemble elements manually. Therefore, we developed a robotic assembly system (RAS) to prevent accidental falls. The RAS consists of four methods: rotation, alignment, bolting, and unloading. The rotation method utilizes a flywheel equipped on top of a rigging beam to rotate the beam. The vertical alignment relies on a camera and a marker to align the altitude of the beam. The horizontal alignment relies on a specially designed shape that can smoothly guide the beam to the right position. The bolting method adds an additional plug hole above each bolt hole to assemble the beam. The unloading method uses pin mechanisms and motors to unload the cable and the RAS. The system is tested in a scaled indoor experiment and the results show that the process is finished without workers stay in the high place. In conclusion, the RAS helps reduce accidental falls, is suitable to the current erection method, and can be broadly introduced to existing sites
From Digital to Physical: Advancing Industrialized Construction through Digital Prototyping Processes
Get PDFRecent development in digital design strategies and fabrication tools has offered the Architecture, Engineering, and Construction (AEC) industry the opportunity to rethink the prefabricated building industry. Different methodologies have been proposed with the aim of formulating an efficient link between design and fabrication processes, based on devising effective data workflows to overcome complexities associated with conventional production models. This paper demonstrates recent developments in implementing a Digital Prototyping model toward establishing a comprehensive strategy for design and fabrication of a family of building components. The proposed model is specifically designed and implemented to realize a prefabricated construction system, BONE Structure®, with the aim of enabling high precision in design and fabrication, in addition to supporting pre-defined assembly on jobsites. This paper represents a phase from an ongoing research endeavor toward infusing the design and production processes with digital logic, aiming for high flexibility and customization in building design, specifically the housing realm
Modular Home off-site Construction Production Line Improvement
Get PDFToday modular and off-site construction practices are widely used as a novel approach to residential and commercial building construction. Although this approach is known for its high production efficiency and low material waste, manufacturers are facing the challenge of fully differentiating their modular construction procedures from the conventional construction approach. Manufacturers are thus seeking to continuously implement efficient methodologies to improve their production line effectiveness, thereby enhancing their market competitiveness. This paper proposes a methodology enabling the modular manufacturer to overcome this challenge and increase their assembly line productivity by implementing building information modelling (BIM)-supported lean manufacturing concepts, with a particular focus on the importance of the upstream pre-assembly line. This technique was implemented on a case-study, a residential modular factory, and increased the production line productivity by implementing the Lean-assembly concept. This approach is supported by the information provided from an enhanced BIM model generated to deliver accurate resource quantity required at each assembly station
Older Adult-Centred Design
Get PDFA poorly designed home environment is likely to cause falling for older adults. By employing the concept of older adult-centred design, home design that reduces the risk of falls for older adults can be achieved. This approach focuses on meeting specific human needs and enabling individuals to experience improved functionality within the living space. This paper presents an evidencebased analysis of bathroom design from the perspective of reducing the risk of falling for older adults. The methodology is divided into three stages: (1) evidence-based review of bathroom design; (2) cohesive analysis of evidence-based studies; and (3) definition of best practice for older adult-centred design. The outcome of this paper is an evidence-based approach to older adultcentred design that is associated with the minimum risk of falling
A Framework for Comparative Evaluation of the Life Cycle Sustainability of Modular and Conventional Buildings
Get PDFIn recent decades, the construction industry has experienced the process of industrialization and off-site construction methods have been used as a substitute for their conventional on-site counterparts. Off-site construction is defined as a process, in which building elements and components are manufactured and preassembled off the construction site, in a factory environment, before their installation on the final project location. Modular construction is one of the main methods of off-site construction that can be applied to diverse types of buildings, ranging from a small residential building to a complicated commercial project. The published technical literature indicates that modular buildings offer numerous benefits that can effectively contribute to the sustainability in construction. However, there is a lack of comparative studies, which comparatively analyzed the life cycle sustainability performance of modular and conventional buildings. This paper proposes a life cycle sustainability assessment (LCSA) framework based on the analytic hierarchy process (AHP), which is one of the multicriteria decision making (MCDM) techniques. This framework evaluates and compares the life cycle sustainability of modular and conventional buildings by addressing all the key sustainability dimensions, i.e., environmental, economic, and social. Different components of the proposed framework and the potential outcomes of its application are presented in this paper
Behavior of Double Fish Plate Connector between Steel Plate Shear Wall Structure and Steel Frame
Get PDFThis paper mainly researched the behavior of double fish plate connector between steel plate shear wall structure and steel frame. Four single fish plate connectors and four double fish plate connectors were tested under monotonic and cyclic loading. The hysteretic curves, skeleton curves, stiffness degradation curve and ductility coefficient were considered to study the behavior of two connections. Results showed that the behavior of double fish plate connector between steel plate shear walls and steel frame was better than single fish plate connector. Double fish plate connectors had higher bearing capacity, slower stiffness degradation, better ductility and better energy dissipation capacity. Constraint effect of steel plate shear walls became stronger, and the out-of-plane buckling failure of steel plate shear walls was delayed. Therefore, the double fish plate connectors could improve the behavior of connection between steel plate shear walls and steel frame, and provide a reference for engineering applicatio
Modelling International Project Feasibility of Sustainable Construction Management: Case Study of Tele-Communication Towers
Get PDFThis paper presents a new conceptual model for feasibility study of projects incorporating sustainability criteria. Large construction projects have an important influence on the attainment of sustainable development indices. Some of these projects particularly in developing countries have not sufficiently considered sustainability issues even with the participation of international companies in these projects during the feasibility phase as well as other phases such as design and operation. Previous studies have not addressed the relevance of the project feasibility phase in terms of sustainability performance. This paper is a result of the initial stages of an on-going study to develop a rigorous model of construction feasibility with sustainability considerations. Two case studies of similar construction projects were selected from two developing countries. The model for project feasibility study proposed in this paper includes economic, social, and environmental performance criteria in addition to traditional project criteria. The paper suggests there is an urgent need for shifting from the traditional approach of project feasibility study to a new approach embracing sustainability principles
BIM-enabled Modular and Industrialized Construction in China
Get PDFThe Chinese construction market is huge in terms of its size but facing many issues not matching its high speed development, such as low field productivity, unreliable quality, high resource and energy consumption, often safety accidents, and significant environment pollution. Those issues are mainly associated with the old fashion of construction method. The concept of industrialization of construction has been recognized since the establishment of the People’s Republic of China, but did not get well developed until recently the industry is under the pressure of increasing labour cost and the demand of sustainable development. There was a surge of Building Information Modeling (BIM) application in last few years in China and the industry has seen lots of benefits of virtual design and construction. Integrating BIM technology into industrialization of construction is seen as a promising opportunity to improve the performance of modular and industrialized construction. This paper first reviews the history of industrialization of the Chinese construction industry and then discusses the recent BIM adoption in China. The approaches of using BIM to enable modular design and industrialized construction and installation in China are the main focus of this paper