Search results for: tunnel construction

Authors: Naik Muhammad, Zahid Ullah, Dong-Ho Choi

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Submerged floating tunnel (SFT) is a new solution for the transportation infrastructure through sea straits, fjords, and inland waters, and can be a good alternative to long span suspension bridges. SFT is a massive cylindrical structure that floats at a certain depth below the water surface and subjected to extreme environmental conditions. The identification of dominant structural response of SFT becomes more important due to intended environmental conditions for the design of SFT. The time domain dynamic problem of SFT moored by vertical and inclined mooring cables/anchors is formulated. The dynamic time history analysis of SFT subjected to hydrodynamic and seismic excitations is performed. The SFT is modeled by finite element 3D beam, and the mooring cables are modeled by truss elements. Based on the dynamic time history analysis the displacements and internal forces of SFT were calculated. The response of SFT is presented for hydrodynamic and seismic excitations. The transverse internal forces of SFT were the maximum compared to vertical direction, for both hydrodynamic and seismic cases; this indicates that the cable system provides very small stiffness in transverse direction as compared to vertical direction of SFT.

Keywords: submerged floating tunnel, hydrodynamic analysis, time history analysis, seismic response

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Authors: Jaehyun Choi, Hyunjung Kim, Namho Kim

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Earthwork is one of the critical civil construction operations that require large-quantities of resources due to its intensive dependency upon construction equipment. Therefore, efficient construction equipment management can highly contribute to productivity improvements and cost savings. Earthwork operation utilizes various combinations of construction equipment in order to meet project requirements such as time and cost. Identification of site condition and construction methods should be performed in advance in order to develop a proper execution plan. The factors to be considered include capacity of equipment assigned, the method of construction, the size of the site, and the surrounding condition. In addition, optimal combination of various construction equipment should be selected. However, in real world practice, equipment utilization plan is performed based on experience and intuition of management. The researchers evaluated the efficiency of various alternatives of construction equipment combinations by utilizing the process simulation model, validated the model from a case study project, and presented a methodology to find optimized plan among alternatives.

Keywords: earthwork operation, construction equipment, process simulation, optimization

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Authors: Pedro Ferreira, Alexandre Frugoli, Pedro Frugoli, Lucio Leonardo, Thais Cavalheri

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The teaching of fluid mechanics in engineering courses is, in general, a source of great difficulties for learning. The possibility of the use of experiments with didactic wind tunnels can facilitate the education of future professionals. The objective of this proposal is the development of a low-cost aerodynamic balance to be used in a didactic wind tunnel. The set is comprised of an Arduino microcontroller, programmed by an open source software, linked to load cells built by students from another project. The didactic wind tunnel is 5,0m long and the test area is 90,0 cm x 90,0 cm x 150,0 cm. The Weq® electric motor, model W-22 of 9,2 HP, moves a fan with nine blades, each blade 32,0 cm long. The Weq® frequency inverter, model WEGCFW 08 (Vector Inverter) is responsible for wind speed control and also for the motor inversion of the rotational direction. A flat-convex profile prototype of airfoil was tested by measuring the drag and lift forces for certain attack angles; the air flux conditions remained constant, monitored by a Pitot tube connected to a EXTECH® Instruments digital pressure differential manometer Model HD755. The results indicate a good agreement with the theory. The choice of all of the components of this proposal resulted in a low-cost product providing a high level of specific knowledge of mechanics of fluids, which may be a good alternative to teaching in countries with scarce educational resources. The system also allows the expansion to measure other parameters like fluid velocity, temperature, pressure as well as the possibility of automation of other functions.

Keywords: aerodynamic balance, wind tunnel, strain gauge, load cell, Arduino, low-cost education

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Authors: Clare S. Sullivan

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The high desert of central Oregon, USA is a challenging growing environment: short growing season (70-100 days); average annual precipitation of 280 mm; drastic swings in diurnal temperatures; possibility of frost any time of year; and sandy soils low in organic matter. Despite strong demand, there is almost no fruit grown in central Oregon due to potential yield loss caused by early and late frosts. Elsewhere in the USA, protected culture (i.e., high tunnels) has been used to extend fruit production seasons and improve yields. In central Oregon, high tunnels are used to grow multiple high-value vegetable crops, and farmers are unlikely to plant a perennial crop in a high tunnel unless proven profitable. In May 2019, two berry trials were established on a farm in Alfalfa, OR, to evaluate raspberry and strawberry yield, season length, and fruit quality in protected (high tunnels) vs. unprotected culture (open field). The main objective was to determine whether high tunnel berry production is a viable enterprise for the region. Each trial was arranged using a split-plot design. The main factor was the production system (high tunnel vs. open field), and the replicated, subplot factor was berry variety. Four day-neutral strawberry varieties and four primocane-bearing raspberry varieties were planted for the study and were managed using organic practices. Berries were harvested once a week early in the season, and twice a week as production increased. Harvested berries were separated into ‘marketable’ and ‘unmarketable’ in order to calculate percent cull. First-year results revealed berry yield and quality differences between varieties and production systems. Strawberry marketable yield and berry fruit size increased significantly in the high tunnel compared to the field; percent yield increase ranged from 7-46% by variety. Evie 2 was the highest yielding strawberry, although berry quality was lower than other berries. Raspberry marketable yield and berry fruit size tended to increase in the high tunnel compared to the field, although variety had a more significant effect. Joan J was the highest yielding raspberry and out-yielded the other varieties by 250% outdoor and 350% indoor. Overall, strawberry and raspberry yields tended to improve in high tunnels as compared to the field, but data from a second year will help determine whether high tunnel investment is worthwhile. It is expected that the production system will have more of an effect on berry yield and season length for second-year plants in 2020.

Keywords: berries, high tunnel, local food, organic

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Authors: Syed Sohaib Bin Hasib, Hiyam Al-Kilidar

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Meeting project deadlines is a major challenge for most construction projects. In this study, perceptions of contractors, clients, and consultants are compared relative to a list of factors derived from the review of the extant literature on project delay. 59 causes (categorized into 8 groups) of project delays were identified from the literature. A survey was devised to get insights and ranking of these factors from clients, consultants & contractors in the Australian construction industry. Findings showed that project delays in the Australian construction industry are mainly the result of skill shortages, interference in execution, and poor coordination and communication between the project stakeholders.

Keywords: construction, delay factors, time delay, australian construction industry

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Authors: Matthew O. Ikuabe, Ayodeji E. Oke, Clinton O. Aigbavboa, Douglas O. Aghimien

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The use of technological innovations have been touted to be beneficial in the delivery of construction projects. Particularly, Radio Frequency Identification (RFID) technology is widely regarded to be of immense advantage for the management of construction projects. This study focused on evaluating the barriers to the use of Radio Frequency Identification (RFID) technology for the delivery of construction projects. Using Gauteng Provincein South Africa as the study area, questionnaire was used in eliciting responses from construction professionals, which made up the population of the study. Retrieved data was analysed using Mean Item Score and One-Sample t-test. Findings from the study showed that the most significant barriers to the deployment of RFID for construction project delivery are high cost and lack of awareness. Conclusively, the study made recommendations that would aid in the abatement of the barriers to the use of RFID technology for construction project delivery.

Keywords: barriers, construction, project delivery, RFID

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Authors: Preeda Sansakorn, Min An

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In order to be capable of dealing with uncertainties, subjectivities, including vagueness arising in building construction projects, the application of fuzzy reasoning technique based on fuzzy set theory is proposed. This study contributes significantly to the development of a fuzzy reasoning safety risk assessment model for building construction projects that could be employed to assess the risk magnitude of each hazardous event identified during construction, and a third parameter of probability of consequence is incorporated in the model. By using the proposed safety risk analysis methodology, more reliable and less ambiguities, which provide the safety risk management project team for decision-making purposes.

Keywords: safety risk assessment, building construction safety, fuzzy reasoning, construction risk assessment model, building construction projects

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Authors: Nuruddeen Usman, Usman Mohammed Gidado

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A construction and post construction activity in buildings contributes to environmental degradation, because of the generation of solid waste during construction to the production of carbon dioxide by the occupants during utilization. These problems were caused as a result of lack of adopting green building technology during and after construction. However, this study aims at conceptualizing the factors that are affecting the adoption of green building technology with a view to suggest better ways for its successful adoption in the construction industry through developing a green building technology model. Thus, the research findings show that: Economic, social, cultural, and technological progresses are the factors affecting Green Building Technology Adoption. Therefore, identifying these factors and developing the model might help in the successful adoption of green building technology.

Keywords: green building technology, construction, post construction, degradation

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Authors: A. Latif Karimi

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Since 2001, construction works, especially the construction of new homes and residential buildings, witnessed a dramatic boom across Afghanistan. More so, the construction industry and house builders are relied upon as important players in the country’s job market, economy and infrastructural development schemes. However, a lack of innovation, quality assurance mechanism, substandard construction and market dominance by traditional methods push all the parties in house building sector to shift for more advanced construction techniques and mass production technologies to meet the rising demands for proper accommodation. Meanwhile, rapid population growth and urbanization are widening the gap between the demand and supply of new and modern houses in urban areas like Kabul, Herat, etc. This paper investigates about current condition of construction practices in house building projects, the associated challenges, and the outcomes of transition to more reasonable and sustainable building methods. It is obvious, the introduction and use of Modern Methods of Construction (MMC) can help construction industry and house builders in Afghanistan to tackle the challenges and meet the desired standards for modern houses. This paper focuses on prefabrication, a popular MMC that is becoming more common, improving in quality and available in a variety of budgets. It is revealed that this method is the way forward to improving house building practices as it has been proven to reduce construction time, minimize waste and improve environmental performance of construction developments.

Keywords: modern houses, traditional construction, modern methods of construction, prefabrication, sustainable building

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Authors: Hyeon-Seong Kim, Sang-Mi Park, Seul-Gi Kim, Seon-Ju Han, Leen-Seok Kang

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The use of BIM, including 4D CAD system, in a construction project is gradually increasing. Since the building construction works repeatedly in the vertical space, it is relatively easy to confirm the interference effect when applying the BIM, but the interference effect for the civil engineering project is relatively small because the civil works perform non-repetitive processes in the horizontal space. For this reason, it is desirable to apply BIM to the construction phase when applying BIM to the civil engineering project, and the most active BIM tool applied to the construction phase is the 4D CAD function for the schedule management. This paper proposes the application procedure of BIM by the construction phase of civil engineering project and a linear 4D CAD construction methodology suitable for the civil engineering project in which linear work is performed.

Keywords: BIM, 4D CAD, linear 4D simulation, VR

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Authors: Arturo Galván, Jatziri Y. Moreno-Martínez, Israel Enrique Herrera Díaz, José Ramón Gasca Tirado

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In recent years, one of the methods most used for the construction of tunnels in soft soil is the shield-driven tunneling. The advantage of this construction technique is that it allows excavating the tunnel while at the same time a primary lining is placed, which consists of precast segments. There are joints between segments, also called longitudinal joints, and joints between rings (called as circumferential joints). This is the reason because of this type of constructions cannot be considered as a continuous structure. The effect of these joints influences in the rigidity of the segmental lining and therefore in its structural response. A parametric study was performed to take into account the effect of different parameters in the structural response of typical segmental tunnels built in soft soil by using non-linear numerical models based on Finite Element Method by means of the software package ANSYS v. 11.0. In the first part of this study, two types of numerical models were performed. In the first one, the segments were modeled by using beam elements based on Timoshenko beam theory whilst the segment joints were modeled by using inelastic rotational springs considering the constitutive moment-rotation relation proposed by Gladwell. In this way, the mechanical behavior of longitudinal joints was simulated. On the other hand for simulating the mechanical behavior of circumferential joints elastic springs were considered. As well as, the stability given by the soil was modeled by means of elastic-linear springs. In the second type of models, the segments were modeled by means of three-dimensional solid elements and the joints with contact elements. In these models, the zone of the joints is modeled as a discontinuous (increasing the computational effort) therefore a discrete model is obtained. With these contact elements the mechanical behavior of joints is simulated considering that when the joint is closed, there is transmission of compressive and shear stresses but not of tensile stresses and when the joint is opened, there is no transmission of stresses. This type of models can detect changes in the geometry because of the relative movement of the elements that form the joints. A comparison between the numerical results with two types of models was carried out. In this way, the hypothesis considered in the simplified models were validated. In addition, the numerical models were calibrated with (Lab-based) experimental results obtained from the literature of a typical tunnel built in Europe. In the second part of this work, a parametric study was performed by using the simplified models due to less used computational effort compared to complex models. In the parametric study, the effect of material properties, the geometry of the tunnel, the arrangement of the longitudinal joints and the coupling of the rings were studied. Finally, it was concluded that the mechanical behavior of segment and ring joints and the arrangement of the segment joints affect the global behavior of the lining. As well as, the effect of the coupling between rings modifies the structural capacity of the lining.

Keywords: numerical models, parametric study, segmental tunnels, structural response

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Authors: Faraz Ali Memon

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Stakeholders are a vital part of any organisation. It includes working on the demands of different stakeholders within the projects. However, the reality of construction projects is slightly different when it comes to practice. The UK construction projects have a history of failing to complete projects on time and within the budget. The purpose of this qualitative study is to enhance knowledge of stakeholder engagement. Semi-structured interviews will be carried out using a purposive sampling technique. It includes interviewing and getting knowledge from industry practitioners from top UK construction firms on how to manage stakeholders effectively. The findings from this study will help in understanding stakeholders' impact and how the engagement of stakeholders can affect construction projects. The conclusions of this study add value to the existing body of knowledge on stakeholder management, especially in the UK, where academic studies on construction projects are few. As a contribution, this study will provide a practical guide for the practitioners to engage stakeholders within the scope of the project. In addition, this study is limited to UK construction projects. Therefore, the outcome may not be generalised to other developing and underdeveloped countries.

Keywords: stakeholders, UK construction, project management, cost and time

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Authors: Aftab Hameed Memon, Shadab Noor, Muhammad Akram Akhund

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Lean construction is a philosophy adopted in the construction industry to increase the value of a project by reducing waste and improving construction productivity. Lean emphasizes on maximizing the value of a project with less expenditure. Globally, lean philosophy has received wider popularity in construction sector. Lean construction has supported the practitioners with several tools and techniques to implement at various stages of a construction project. Following the global trends, this study has investigated the lean practice in Pakistan. The level of implementation of different lean tools and techniques altogether with potential benefits experienced by its implementation in construction projects of Pakistan is analyzed. To achieve the targets, the opinion was sought by the practitioners involved in handling construction projects representing four stakeholders that are a client, consultant, contractors and material suppliers through a structured questionnaire. A total of 34 completed questionnaires were collected and then statistically analyzed. The findings of the analysis have highlighted that pull approach, work standardization, just in time, increase visualization tools, integrated project delivery method and fail-safe for quality are common lean techniques implemented in the local construction industry. While reduction in waste, client’s satisfaction, improved communication, visual control and proper task management are major benefits of the lean construction application.

Keywords: lean construction, lean tools and techniques, lean benefits, waste reduction, Pakistan

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Authors: Zhenyu Yang, Qiunan Chen, Xiaocheng Huang

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Reliable prediction of tunnel collapse remains a prominent challenge in the field of civil engineering. In this study, leveraging the nonlinear Hoek-Brown failure criterion and the upper-bound theorem, an analytical solution for the collapse surface of shallowly buried circular tunnels was derived, taking into account the coupled effects of surface loads and pore water pressures. Initially, surface loads and pore water pressures were introduced as external force factors, equating the energy dissipation rate to the external force, yielding our objective function. Subsequently, the variational method was employed for optimization, and the outcomes were juxtaposed with previous research findings. Furthermore, we utilized the deduced equation set to systematically analyze the influence of various rock mass parameters on collapse shape and extent. To validate our analytical solutions, a comparison with prior studies was executed. The corroboration underscored the efficacy of our proposed methodology, offering invaluable insights for collapse risk assessment in practical engineering applications.

Keywords: tunnel roof stability, analytical solution, hoek–brown failure criterion, limit analysis

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Authors: A. M. Naraghi, V. Gonzalez, M. O'Sullivan, C. G. Walker, M. Poshdar, F. Ying, M. Abdelmegid

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Discrete Event Simulation (DES) and Agent Based Simulation (ABS) are two simulation approaches that have been proposed to support decision-making in the construction industry. Despite the wide use of these simulation approaches in the construction field, their applications for production and material planning is still limited. This is largely due to the dynamic and complex nature of construction material supply chain systems. Moreover, managing the flow of construction material is not well integrated with site logistics in traditional construction planning methods. This paper presents a hybrid of DES and ABS to simulate on-site and off-site material supply processes. DES is applied to determine the best production scenarios with information of on-site production systems, while ABS is used to optimize the supply chain network. A case study of a construction piling project in New Zealand is presented illustrating the potential benefits of using the proposed hybrid simulation model in construction material flow planning. The hybrid model presented can be used to evaluate the impact of different decisions on construction supply chain management.

Keywords: construction supply-chain management, simulation modeling, decision-support tools, hybrid simulation

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Authors: Soo-yeon Seo, Seol-ki Kim, Su-jin Jung

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In the construction of a building, it is necessary to minimize construction period and secure enough work space for stacking of materials during the construction especially in city area. In this manner, various top-down construction methods have been developed and widely used in Korea. This paper investigates the stress variation of underground structure of a building constructed by using SPS (Strut as Permanent System) known as a top-down method in Korea through an analytical approach. Various types of earth pressure distribution related to ground condition were considered in the structural analysis of an example structure at each step of the excavation. From the analysis, the most high member force acting on beams was found when the ground type was medium sandy soil and a stress concentration was found in corner area.

Keywords: construction of building, top-down construction method, earth pressure distribution, member force, stress concentration

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Authors: Hassan Abdelgadir

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Cost overruns have harmed the economies and reputations of several construction companies around the world. Many project management systems have been developed to keep track of a project's budget. However, due to several cost overrun difficulties in the construction industry, cost management is still deemed inadequate. As a result, the goal of this term paper is to identify and group prospective construction project cost overrun reasons based on their origin groups.Basically, all potential cost overrun elements were rigorously checked through 1iterature analysis before being divided into seven (7) groups of originating components, including project, contract, client, contractor, consultant, labor, and external. Each potential factor was completely defined with examples.

Keywords: construction projects, cost overruns, construction company, factors effect costoverruns

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Authors: Gurbir Singh Khaira, Anmoldeep Singh Kang

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Exposures to environmental pollution remain a major source of health risk throughout the world, though risks are generally higher in developing countries, where poverty, lack of investment in modern technology and weak environmental legislation combine to cause high pollution levels. This paper will tell us about the environment is threatened severely by so many problems, some of which are caused by the activities of Construction Projects. The research reveals major environmental impacts of building construction projects to include environmental pollution, resource depletion and habitat destruction causing Destruction of ecosystem, Desertification, Soil Erosion and increasing Material Wastage. Construction is considered as one of the main sources of environmental pollution in the world, the level of knowledge and awareness of project participants, especially project managers, with regards to environmental impacts of construction processes needs to be enhanced. It was found that ‘Transportation Resource’, ‘Noise Pollution’, and ‘Dust Generation with Construction Machinery’ are the greatest environmental impacts in INDIA respectively. The results of this study are useful for construction managers and other participants in construction sites to become aware of construction processes impacts on the environment.

Keywords: construction projects, environmental impacts, material waste age, awareness

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Authors: S. A. Anuar, N. H. Hamid, M. H. Hashim, S. M. D. Salleh

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This paper present the experimental work on the seismic performance of double unit tunnel form building (TFB) subjected to in-plane lateral cyclic loading. A one third scale of 3-storey double unit of TFB is tested at ±0.01%, ±0.1%, ±0.25%, ±0.5%, ±0.75% and ±1.0% drifts until the structure achieves its strength degradation. After that, the TFB is repaired and retrofitted using additional shear wall, steel angle and CFRP sheet. A similar testing approach is applied to the specimen after repair and retrofit. The crack patterns, lateral strength, stiffness, ductility and equivalent viscous damping (EVD) were analyzed and compared before and after repair and retrofit. The result indicates that the lateral strength increases by 22 in pushing direction and 27% in pulling direction. Moreover, the stiffness and ductility obtained before and after retrofit increase tremendously by 87.87% and 39.66%, respectively. Meanwhile, the energy absorption measured by equivalent viscous damping obtained after retrofit increase by 12.34% in pulling direction. It can be concluded that the proposed retrofit method is capable to increase the lateral strength capacity, stiffness and energy absorption of double unit TFB.

Keywords: tunnel form building, in-plane lateral cyclic loading, crack pattern, lateral strength, stiffness, ductility, equivalent viscous damping, repair and retrofit

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Authors: G. Robles, A. Stifi, José L. Ponz-Tienda, S. Gentes

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This research paper aims to identify, analyze and rank factors affecting labor productivity in Spain with respect to their relative importance. Using a selected set of 35 factors, a structured questionnaire survey was utilized as the method to collect data from companies. Target population is comprised by a random representative sample of practitioners related with the Spanish construction industry. Findings reveal the top five ranked factors are as follows: (1) shortage or late supply of materials; (2) clarity of the drawings and project documents; (3) clear and daily task assignment; (4) tools or equipment shortages; (5) level of skill and experience of laborers. Additionally, this research also pretends to provide simple and comprehensive recommendations so that they could be implemented by construction managers for an effective management of construction labor forces.

Keywords: construction management, factors, improvement, labor productivity, lean construction

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Authors: Md. Aftabuzzaman, Md. Kamruzzaman

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Road-related expenditure and building construction activity are two significant drivers of the Victorian economy. This paper investigates the relationship between building construction activity and road-related expenditure. Data for construction activities were collected from Victorian Building Authority, and road-related expenditure data were explored by the Bureau of Infrastructure and Transport Research Economics. The trend between these two sectors was compared. The analysis found a strong relationship between road-related expenditure and the volume of construction activity, i.e., the more construction activities, the greater the requirement of road-related expenditure, or vice-versa. The road-related expenditure has a two-year lag period, suggesting that the road sector requires two years to respond to the growth in the building sector.

Keywords: building construction activity, infrastructure, road expenditure, Victorian Building Authority

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Authors: Abdullah Mohammed Alshehri

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The projects in the construction industry have significantly increased, given its contribution to the overall Gross Domestic Product (GDP) of the countries. Reflecting upon the complex nature and involvement of various agents, the study aims to analyze the conflicts cause within construction projects. Therefore, the study strived to come out with understanding the levels of conflict interaction across project phases. However, this conducted by investigating the association between antecedents and apparent conflicts inherent in. The study used a qualitative approach for collecting the data through a quantitative, semi-structured method. Formation of a questionnaire survey has been conducted for over 30 respondents. However, the survey came out with the identification of 25 conflict cause categories, which can take place in different construction project phases, including pre-design phase, pre-construction phase, construction phase, commissioning, and completion phase. For example, conflicts associated with inconsistencies or discrepancies within or between project documents, which took place at tendering time in the pre-construction phase were relatable with the selection of material specifications that should be supplied or used in the construction projects at the construction phase. Its analysis can provide comprehensive understanding, trace the root of the problem, which offers a roadmap to deepen the understanding of the conflict conditions and ‘course of action’ necessary for project management strategy actions toward avoiding or minimizing conflict causes at project life.

Keywords: construction, conflict causes, levels, interaction, phases

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Authors: Jyoti Singh, Ahmed Stifi, Sascha Gentes

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The process of construction significantly contributes to high level of risks, complexity and uncertainties leading to cost and time overrun, customer dissatisfaction etc. lean construction is important as it is a comprehensive system of tools and concepts focusing on moving closer to customer satisfaction by understanding the process, identifying the waste and eliminating it. The proposed work includes identification of knowledge areas from lean perspective, lean tools/concepts used in lean construction and establishing a relationship matrix between knowledge areas and lean tools/concepts, thus developing and building up a lean construction body of knowledge (LCBOK), i.e. a guide to lean construction, aiming to provide guidelines to manage individual projects and also helping construction industry to minimise waste and maximize value to the customer. In this study, we identified 8 knowledge areas and 62 lean tools/concepts from lean perspective and also one tool can help to manage two or more knowledge areas.

Keywords: knowledge areas, lean body matrix, lean construction, lean tools

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Authors: Samira Haghbin, Behnam Daryayelaal, Zeinab Amiri

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As a result of rapid progress of technology in various industries, the only way to survive in a competitive market of business is to update one's situation along with the said developments. During recent decades, Robotics and automation of the construction operation has emerged as one of the important technologies grabbing the attention of various industries and specially the construction industry. Because of the coming labor shortage of the aging society in the near future, robots will be used in construction fields more than ever. By predicting the condition of Robotics in world's future construction industry, we can make necessary preparations to face with needs imposed by the time and stay ahead. This article takes a library study approach and presents a literature review of existing studies with an aim to investigate the use of robotics in past, present and future of construction industry and make predictions on its' growth and change process. Therefore, to make familiar with this kind of technology and its' requirements in the construction industry, the status of Robotics in construction industry of different countries of the world has been studied and necessary context for its' future progress is expressed. It is hoped that identifying needs and required contexts will facilitate further development of advanced technologies such as robotics industry and lead to more preparation for future.

Keywords: future of robotics, construction industry, construction automation, trends of automation

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Authors: Nuruddeen Usman, Usman Mohammed Gidado, Muhammad Ahmad Ibrahim

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Construction industry is one of the sectors that are eyeing adoption of ICT for its development due to the advancement in technology. Though, many manufacturing sectors had been using it, but construction industry was left behind, especially in the developing nation like Nigeria. On account of that, the objective of this study is to conceptually and quantitatively synthesise whether the slow adoption of ICT by the construction industries can be attributable to cybercrime threats. The result of the investigation found that, the risk of cybercrime, and lack of adequate cyber security policies that can enforce and punish defaulters are among the things that hinder ICT adoption of the Nigerian construction industries. Therefore, there is need for the nations to educate their citizens on cybercrime risk, and to establish cybercrime police units that can be monitoring and controlling all online communications.

Keywords: construction industry, cybercrime, information and communication technology adoption, risk

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Authors: Ezekiel Ejiofor Nnadi

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Nigeria construction industry is known for its active construction activities. This has earmarked the industry to be the key to economic growth of the nation. It has largest employer of labour and gives sustenance to other industries like manufacturing industry. While this is a sign of growth and prosperity; the waste generated by the industry has always been a problem and a serious concern. It results in wastage of economic gain and has resultant health effect on the populace apart from injury being sustained on sites. This work provides a platform to learn more about construction waste, its management strategy and how to reduce waste production in Nigeria construction industry. Construction sites, waste management authority and public health institutions in Lagos as the centre of most construction activities in Nigeria were selected, and a set of questionnaire was administered to using the systematic sampling technique. Descriptive statistics and relative importance index (RII) technique were employed for the analysis of the data gathered. The findings of the analysis show that excessive wastes reduce contractors’ profit margin and also that some construction wastes contain hazardous and toxic elements such as lead, asbestos or radioactive materials which required proper handling and effective disposal. The conclusion was drawn that the check on waste on construction sites starts with the designers to the contractors who execute on site.

Keywords: construction cost, construction industry, economic growth, materials wastes

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Authors: Gelacio JuáRez-Luna, Daniel Enrique GonzáLez-RamíRez, Enrique Tenorio-Montero

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Frame elements coupled with springs elements are used for modelling the development of hinges in segmented tunnels, the spring elements modelled the rotational, transversal and axial failure. These spring elements are equipped with constitutive models to include independently the moment, shear force and axial force, respectively. These constitutive models are formulated based on damage mechanics and experimental test reported in the literature review. The mesh of the segmented tunnels was discretized in the software GID, and the nonlinear analyses were carried out in the finite element software ANSYS. These analyses provide the capacity curve of the primary and secondary lining of a segmented tunnel. Two numerical examples of segmented tunnels show the capability of the spring elements to release energy by the development of hinges. The first example is a segmental concrete lining discretized with frame elements loaded until hinges occurred in the lining. The second example is a tunnel with primary and secondary lining, discretized with a double ring frame model. The outer ring simulates the segmental concrete lining and the inner ring simulates the secondary cast-in-place concrete lining. Spring elements also modelled the joints between the segments in the circumferential direction and the ring joints, which connect parallel adjacent rings. The computed load vs displacement curves are congruent with numerical and experimental results reported in the literature review. It is shown that the modelling of a tunnel with primary and secondary lining with frame elements and springs provides reasonable results and save computational cost, comparing with 2D or 3D models equipped with smeared crack models.

Keywords: damage, hinges, lining, tunnel

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Authors: Yuanyuan Liu, Yuanqing Wang, Di Li

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Carbon dioxide (CO2) emissions mitigation from road construction activities is one of the potential pathways to deal with climate change due to its higher use of materials, machinery energy consumption, and high quantity of vehicle and equipment fuels for transportation and on-site construction activities. Aiming to assess the environmental impact of the road infrastructure construction activities and to identify hotspots of emissions sources, this study developed a life-cycle CO2 emissions assessment framework covering three stages of material production, to-site and on-site transportation under the guidance of the principle of LCA ISO14040. Then streamlined inventory analysis on sub-processes of each stage was conducted based on the budget files from cases of highway projects in China. The calculation results were normalized into functional unit represented as ton per km per lane. Then a comparison between the amount of emissions from each stage, and sub-process was made to identify the major contributor in the whole highway lifecycle. In addition, the calculating results were used to be compared with results in other countries for understanding the level of CO2 emissions associated with Chinese road infrastructure in the world. The results showed that materials production stage produces the most of the CO2 emissions (for more than 80%), and the production of cement and steel accounts for large quantities of carbon emissions. Life cycle CO2 emissions of fuel and electric energy associated with to-site and on-site transportation vehicle and equipment are a minor component of total life cycle CO2 emissions from highway project construction activities. Bridges and tunnels are dominant large carbon contributor compared to the road segments. The life cycle CO2 emissions of road segment in highway project in China are slightly higher than the estimation results of highways in European countries and USA, about 1500 ton per km per lane. In particularly, the life cycle CO2 emissions of road pavement in majority cities all over the world are about 500 ton per km per lane. However, there is obvious difference between the cities when the estimation on life cycle CO2 emissions of highway projects included bridge and tunnel. The findings of the study could offer decision makers a more comprehensive reference to understand the contribution of road infrastructure to climate change, especially understand the contribution from road infrastructure construction activities in China. In addition, the identified hotspots of emissions sources provide the insights of how to reduce road carbon emissions for development of sustainable transportation.

Keywords: carbon dioxide emissions, construction activities, highway, life cycle assessment

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Authors: Syed Hassan Raza Shah, Mohammad Mohammad Ali

Abstract:

The flow over a smoothly profiled airfoil at a low Reynolds number is highly susceptible to separate even at a very low angle of attack. An investigation was made to study the effect of leading-edge and trailing-edge corrugation with the spanwise change in the ridges resulted due to the change in the chord length for an infinite wing. The wind tunnel results using NACA0018 wings revealed that leading and trailing edge corrugation did not have any benefit in terms of aerodynamic efficiency or delayed stall. The leading edge and trailing edge corrugation didn't change the lift curve slope, with the leading edge corrugation wing stalling first in the range of Reynolds number of 50,000 to 125,000.

Keywords: leading and trailing edge corrugations, low reynolds number, wind tunnel testing, NACA0018

Procedia PDF Downloads 251

Authors: Muhamad Azani Yahya, Vikneswaran Munikanan, Mohammed Alias Yusof

Abstract:

Lean thinking holds the potential for improving the construction sector, and therefore, it is a concept that should be adopted by construction sector players and academicians in the real industry. Bridging from that, a learning process for construction sector players regarding this matter should be the agenda in gaining the knowledge in preparation for their career. Lean principles offer opportunities for reducing lead times, eliminating non-value adding activities, reducing variability, and are facilitated by methods such as pull scheduling, simplified operations and buffer reduction. Thus, the drive for rapid construction, which is a systematic approach in enhancing efficiency to deliver a project using time reduction, while lean is the continuous process of eliminating waste, meeting or exceeding all customer requirements, focusing on the entire value stream and pursuing perfection in the execution of a constructed project. The methodology presented is shown to be valid through literature, interviews and questionnaire. The results show that the majority of construction sector players unfamiliar with lean thinking and they agreed that it can improve the construction process flow. With this background knowledge established and identified, best practices and recommended action are drawn.

Keywords: construction improvement, rapid construction, time reduction, lean construction

Procedia PDF Downloads 345