A proactive system for real-time safety management in construction sites

Construction sites still present high accident rates. The advent of advanced sensing technologies has motivated the development of unprecedented automated systems, capable of supporting health and safety control. Their application is particularly critical in those cases where regular safety inspections may prove to be inadequate in terms of preventing risks which, because of their specific nature, are unpredictable.This paper reports the development of a first prototype for the proactive safety management and real-time signaling of potential overhead hazards. It is expected to enhance standard safety policies and assist inspectors and coordinators in executing their tasks. The system performs real-time tracking using ultra wide band technology and implements proactive virtual fencing logics. The development of the system, its laboratory test results, the algorithm optimization, and the final field test results are reported herein. The results achieved demonstrate the capability of proactive logics to reinforce safety management policies and assist personnel in coping with unpredictable hazardous events.     

Improved indoor environment through optimised ventilator and furniture positioning: A case of slum rehabilitation housing,Mumbai, India

This study optimized the ventilator and furniture location of a tenement unit in a low-income urban habitat to obtain maximum experiential indoor environmental quality (e-IEQ) over the breathing zone. Hypothetical interior layouts using a combination of the two design parameters of ventilator location and bed position were generated for optimizing the design layout. This layout could promote maximum indoor airflow and minimum indoor air temperature and contaminant concentration. In this study, an improved indoor environment is hypothesized to be attainable through improved natural ventilation and thermal performance in the occupied zones. A sequential methodology involving “parametric design modeling–computational simulation–multiobjective optimization–multicriteria decision making”-based framework was selected. Results exhibited that the currently designed tenement unit had a poor indoor environment, whereas the hypothesized iterated layout “optimized design layout, scenario 3 (ODL 3)” derived from the optimization and decision-making algorithm performed effectively in providing e-IEQ. An increase in experiential indoor air velocity by 0.2 m/s and a decrease in temperature by 2 °C were observed over the monitoring point in the ODL 3 considering the existing scenario. Therefore, this study can find a way toward the development of sustainable habitat design guidelines under upcoming slum redevelopment policies across the nation.     

A group decision support system for implementing value management methodology in construction briefing

This paper describes a group decision support system (GDSS) developed in response to the need of a computer supported collaborative work environment for implementing the value management (VM) methodology in construction briefing. The GDSS is based on the VM methodology that allows a client to define and represent his or her requirements with functions and functional performance, to bring forward ideas to achieve the functions, and finally to evaluate and highlight the ideas against the functional performance for further development in design. The conceptual framework, design, implementation, use of the GDSS are addressed and described in that order. The system is complementally evaluated through a field study and an experimental study. It is concluded that the GDSS can effectively facilitate the implementation of VM in construction briefing. In addition, the GDSS has big potential to improve the performance of VM studies in terms of the enhanced participation and interaction, the shortened time for tasks, and the improved satisfaction with VM workshops. Research limitations and knowledge contribution of this study are also discussed.     

Soil nailing at the tunnel face in difficult conditions: A case study

In presence of difficult conditions in tunnelling, an adequate stabilization of the excavation boundary and face is required to ensure a safe progress of the construction. The stabilization of the tunnel face can be improved by fibreglass soil nailing, offering properties optimal to the purpose and versatility in use. This paper reports a tunnelling experience where difficult conditions, induced by poor mechanical properties of the rock mass and relevant pore water pressures, were faced adopting innovative soil nailing techniques. Some details about the site geological conditions allow to recognize the causes of the difficult conditions which drove towards specific choices about the features of soil nails, acting on both aspects of mechanical reinforcement and drainage. The soil nail mechanical contribution to the tunnel face stabilization is taken into account at the design stage by an equivalent increase of effective cohesion in the improved ground mass. The tunnel face stability is then assessed by analytical approach. The performance and the specific advantages of the innovative technique are discussed also on the basis of results from on site testing.     

A case study into the language structure of construction standard form in Malaysia

Different interpretation could denote a dispute regarding the contractual obligations and expectation between the contracting parties. This paper addresses the need for clarity of standard form in Malaysia. Hence the objectives are to identify the problems in the language structure of standard form from the viewpoint of professionals, and the measures for improving the language structure of standard form. The research aims to mitigate or prevent construction disputes through better interpretation and understanding of construction contracts, and it offers a proactive approach to avoid the inevitability of conflicts occurring in a project. The data collection was mainly by questionnaire survey. Two experts from construction contracting were appointed to approve the questionnaire design and verify the research outcomes. The results identified eight clarity aspects and three legalese problems of language structure in PWD 203A (Rev. 10/83) Form. Besides, twelve out of thirteen measures were agreed upon by the respondents as to ways for improving the language structure. It is concluded that clarity needs to be considered in future contract drafting towards the understanding of standard forms, and thereby to contribute to the avoidance of disputes.     

Differential management of waste by construction sectors: a case study in Michigan,USA

Waste is a great problem in the world of construction. If dealt with appropriately, there can be many benefits, including lower overall cost, faster production, a higher quality and more sustainable buildings. There are many solutions available for minimizing waste during construction. However, a great amount of waste still exists, whether in residential, commercial, industrial, infrastructural or other constructions. The purpose of this investigation is to ascertain key sources of waste, and whether generation varies with the type and size of the constructors. A sample of 30 general contractors was studied, and several null hypotheses on waste generation and minimization differences among sectors were tested using the Kruskal–Wallis H‐test. Although subtle shifts were observed in the aspects of waste behaviour that seemed predicated on construction sectors and capital base, to some extent the proposition that the construction type and size can influence waste generation and minimization was validated. Based on this study, some solutions are provided as viable avenues to managing and minimizing construction waste across sectors.     

Selection of an ERP system for a construction firm in Taiwan: A case study

The primary functions of Enterprise Resource Planning (ERP) are to integrate the inter-departmental operation procedures and Management Information System (MIS) modules, and to reallocate the resources of a company. How to successfully implement an ERP system in an organization is always a hot research topic for researchers as well as a pending problem for an organization that wants to implement it. This research is a case study on the selection of system suppliers and contract negotiation during the ERP implementation of a local construction company in Taiwan. After reviewing the common key success factors discussed in the literature, this study discussed seven issues: coding system, working process reengineering, priority of ERP functionality implementation, customization, participant roles, consultant role and performance level of subcontractor, which also affected the implementation. Lessons learned from the case study in discussed seven issues are valuable for a construction company in deciding to implement an ERP system. This research suggests that additional case studies are necessary for the successful application of ERP systems in the construction industry.     

Influence of Benoto bored pile construction on nearby existing tunnel: A case study

The monitoring and analysis of lateral displacement for metro tunnels are very important because the metro systems are the lifeline of metropolises. This paper presents a case study of a site in Nanjing, China, where the Benoto bored piles were constructed nearby the existing tunnel. The construction technology, a combination of the Benoto bored piles construction and the conventional construction technology of circulating slurry, is illustrated in detail. The lateral displacement at six test sections were measured and discussed to assess the impact of piles installation on the stability and integrity of the existing tunnel. The measured results showed that during the construction period using the Benoto method, relatively large lateral displacement occurred at the depth with soft soil (Mucky silty clay), with characteristics including a large void ratio, high plasticity, poor permeability, high water content, low shear strength, and low modulus of deformation. During the construction period of the conventional Circulating-Slurry method, negative lateral displacement occurred below the tip of the casing due to the soil arching effect, indicating an inward movement towards the Benoto bored piles. The maximum lateral displacement decreased as the distance between piles and inclinometers increased, with a maximum difference of 45% at the end of the measurements. It was also observed that the measured maximum lateral displacement was less than the cumulative trigger value of 20 mm, indicating an effectiveness of Benoto bored piles constructed adjacent to existing tunnel. This case study may provide the means for a qualitative assessment for engineering constructions where the situation bears similarities.     

A multi-purpose prototype test system for mechanical behavior of tunnel supporting structure: Development and application

A multi-purpose prototype test system is developed to study the mechanical behavior of tunnel supporting structure, including a modular counterforce device, a powerful loading equipment, an advanced intelligent management system and an efficient noncontact deformation measurement system. The functions of the prototype test system are adjustable size and shape of the modular counterforce structure, sufficient load reserve and accurate loading, multi-connection linkage intelligent management, and high-precision and continuously positioned noncontact deformation measurement. The modular counterforce structure is currently the largest in the world, with an outer diameter of 20.5 m, an inner diameter of 16.5 m and a height of 6 m. The case application proves that the prototype test system can reproduce the mechanical behavior of the tunnel lining during load-bearing, deformation and failure processes in detail.     

The application of JIT philosophy to construction: a case study in site layout

The just-in-time (JIT) philosophy has been used in the manufacturing industry for some forty to fifty years. This system increased not only the productivity of the industry but also the quality of its products. Explorative studies have been completed in recent years to see how JIT can be applied into the construction industry to reap the benefits of the system. Most of these studies have concluded that it is possible to apply the techniques of JIT in the construction industry with some modifications. Taking into consideration that one of the key components of site management is concerned with waste management (i.e. bringing wastage down to the minimum), this study focuses on applying JIT for site layout to improve productivity and quality. By eliminating waste on site, controlling the movement of inventory coming into the site and within the site, and controlling the usage of mechanized plant and equipment, smooth work flow can be achieved.     

Financial evaluation program for construction projects at the pre-investment phase in developing countries: A case study

The construction industry in the Middle East represents a significant part of the world's economy. Millions of dollars are spent each year on different construction projects. These projects normally pass through several phases starting from pre-investment phase, conception design phase and finally the construction and commissioning phases. Financial management is a creative organized approach with an objective to minimize financing risks. It focuses on financial evaluation as an important issue; in that it has long been an area of attention of construction practitioners and researchers.     

Drivers of productivity among construction workers: A study in a developing country

This paper reports on a study of factors affecting productivity among members of the construction workforce in Turkey. A survey of 82 construction firms in Turkey is undertaken using a questionnaire of 54 questions directed to managers, engineers, architects, and other technical staff. Using the results of the survey, economic and socio-psychological factors that affect labour performance are evaluated and discussed in detail. The results show that monetary factors remain pre-eminent in influencing productivity, but that socio-psychological factors appear to be of increasing importance in this developing economy.     

Estimation of direct solar irradiance intercepted by a solar concentrator in different modes of tracking (case study: Algeria)

While reasonably accurate knowledge of solar radiation data at the location of interest is necessary for the design of any solar energy conversion system, the use of concentrating solar collectors implies that these systems only work with the direct solar irradiance. In the present study, by using a methodology based on simple equations, the total hourly, daily, monthly and annual direct radiations incident on four different oriented solar concentrators were calculated only from the recorded data of monthly mean daily global and diffuse horizontal solar irradiance for three different Algerian sites, in order to choose the best mode of tracking for concentrating solar thermal power systems and concentrating solar photovoltaic power systems applications. The model predictions were found to be consistent with ground measurements and prior studies of Kalogirou. It was found that the greatest energy gains were achieved by using full tracking. Furthermore, the model can be included for application to other Algerian and worldwide locations for estimating direct solar irradiance intercepted by a solar concentrator in different modes of tracking.     

Extraction of chemical impurities for forensic investigations: A case study for indoor releases of a sarin surrogate

A solvent extraction approach was developed and examined for extraction of targeted organophosphorus compounds as well as nerve agent simulants from painted wallboard (PWB). Painted wallboard was chosen as a substrate due to its presence as large surface area media in an indoor environment that is applicable to a chemical agent release scenario. Three different solvent systems were examined with a 1:1 methylene chloride: acetone mixture having the most robust and consistent extraction for four target organophosphorus compounds [dimethyl methyl phosphonate (DMMP), diethyl methyl phosphonate (DEMP), diethyl methyl phosphonothioate (DEMPT), and diisopropyl methyl phosphonate (DIMP)]. An average extraction efficiency of approximately 60% was obtained for these four compounds. The extraction approach was further demonstrated by extracting and detecting the chemical impurities present in neat DMMP that was vapor deposited onto painted wallboard tickets as a simulant to an agent release. Five chemical impurities that were present in DMMP – dimethyl phosphate, trimethyl ester phosphoric acid, ethyl methyl methylphosphonate, O,O,S-trimethyl ester phosphorothioic acid, and biphenyl were detected on the PWB and were utilized to determine the source/supplier of the DMMP.     

An embodied carbon and energy analysis of modern methods of construction in housing: A case study using a lifecycle assessment framework

There is a growing interest in comparing the energy and consequential carbon embodied in buildings using different methods of construction and alternative materials. This paper compares the embodied carbon in a low energy, affordable house constructed using a novel offsite panellised modular timber frame system, in Norfolk UK with two traditional alternative scenarios. A lifecycle assessment (LCA) framework is used to conduct a partial LCA, from cradle to site, of the construction. An inventory of the materials and fossil fuel energy utilised in the construction was used to calculate the primary energy consumed and the associated embodied carbon. The embodied carbon was found to be 34.6 tonnes CO₂ for a 3 bedroom semi-detached house, 405 kgCO₂ per m² of useable floor area. When compared with traditional methods of construction the modern methods of construction (MMC) house resulted in a 34% reduction in embodied carbon. Despite timber being the predominant structural and cladding material, concrete is the most significant material (by proportion) in embodied carbon terms, responsible for 36% of materials related embodied carbon.     

The ritualization of transitions in the project life cycle: A study of transition rituals in construction projects

To manage the project life cycle and facilitate transitions, Project Management (PM) research often points to temporal models and structuring devices. However, the social and symbolic facet of transitions in projects remains understudied. Therefore, this research focuses on the ritualization of transitions in projects. Specifically, the aim is to gain insight into the practice and meaning of transition rituals in the project life cycle. To do so we draw from field research in the infrastructure sector where participant-observation was carried out during eight transition rituals in four Dutch construction projects, and 58 interviews were executed with project participants. The contribution to the PM debate on temporary organizing lies in the conceptualization of transition rituals as powerful symbolic and strategic practices in the project life cycle, and in the provision of an overview showcasing how, when and why transition rituals are practiced to facilitate transitions and embed a project in its environment.     

境外地质勘查测量坐标系统选择——以津巴布韦某矿区为例

本文论述了境外地质勘查项目工作初期矿区测量工作坐标系统的选用问题,简要介绍了坐标系统相关概念及其示例,并从工作实际出发以津巴布韦A矿区为例介绍了该矿区的测量工作史及其所沿用的测量坐标系统及津巴布韦国家现行坐标系统,并分析了在该区近期地质勘查活动所采用的坐标系统情况及其存在的问题,结合矿区历史资料研究分析提出了在矿区的下...     

Neural network analysis of construction safety management systems: a case study in Singapore

A neural network analysis was conducted on a quantitative occupational safety and health management system (OSHMS) audit with accident data obtained from the Singapore construction industry. The analysis is meant to investigate, through a case study, how neural network methodology can be used to understand the relationship between OSHMS elements and safety performance, and identify the critical OSHMS elements that have significant influence on the occurrence and severity of accidents in Singapore. Based on the analysis, the model may be used to predict the severity of accidents with adequate accuracy. More importantly, it was identified that the three most significant OSHMS elements in the case study are: incident investigation and analysis, emergency preparedness, and group meetings. The findings imply that learning from incidents, having well-prepared consequence mitigation strategies and open communication can reduce the severity and likelihood of accidents on construction worksites in Singapore. It was also demonstrated that a neural network approach is feasible for analysing empirical OSHMS data to derive meaningful insights on how to improve safety performance.     

The effect of a redesigned floor plan, occupant density and the quality of indoor climate on the cost of space, productivity and sick leave in an office building–A case study

The aim of this study was to examine changes in the overall costs of an office when the efficiency of space use is increased. The variable in the examination was a space index, calculated as the floor area per employee. The quality of indoor climate was also a variable in the analysis. The overall cost analysis of a given case building showed that when space use is boosted significantly, measures must be taken to guarantee a sufficient quality of indoor climate. The study indicates that investment in the quality of indoor climate is cost-effective when the economic effect of indoor climate to health and productivity are taken into account in addition to the costs of investment, operation and maintenance. Insufficient ventilation without mechanical cooling may cause a substantial loss of productivity. The importance of good ventilation and air-conditioning increases with a more efficient use of space especially in conjunction with high value of work.     

Opening the excavation chamber of the large-diameter size slurry shield: A case study in Nanjing Yangtze River Tunnel in China

Shield tunnel construction in a dense strata often encounters malfunction of shield-tunneling machine or abrasion of cutters. Accessing to an excavation chamber under compressed air is a main method to repair and replace worn cutters. And many safety issues such as stability of the excavation face were involved. However, the face stability due to opening an excavation chamber was not fully studied. To overcome this shortcoming, face support scheme and stability analysis were presented in a case history of opening the pressure chamber for a large-diameter (up to 14.93 m) slurry shield tunnel constructed underneath Nanjing Yangtze River. Since most of the damaged cutters were distributed along the edge of cutting wheel, only top 3 m of tunnel face within the chamber needed to be supported by compressed air, and remaining area would also to be supported by slurry pressure. A series of simple primary laboratory tests were carried out to design an optimum slurries mixing scheme to support the tunnel face as accessing to the pressure chamber in the project. The face stability was analyzed in terms of the pressure equilibrium (i.e., internal and external pressures) as well as three-dimensional numerical analysis by adopting properties of soils and filter cakes from laboratory tests. By injecting lower density slurry into the sand to form a stable infiltration zone, followed by using higher density slurry to create a filter cake at tunnel face, compressed air-support system could ensure face stability during maintenance of cutter wheel. The success of applying the mixed slurry and compressed air-support scheme in this project is valuable to shield tunnel constructions in similar ground conditions.