Specialty Contractors Research Articles

Nature of Occupational Incidents among Roofing Contractors: A Data Mining Approach

Given that roofing contractors in the construction industry have the highest fatality rate among specialty contractors, understanding the root cause of incidents among roofers is critical for improving safety outcomes. This study applied frequency analysis and decision tree data-mining techniques to analyze roofers’ fatal and non-fatal accident reports. The frequency analysis yielded insights into the leading cause of accidents, with fall to a lower level (83%) being the highest, followed by incidence sources relating to structures and surfaces (56%). The most common injuries experienced by roofing contractors were fractures (49%) and concussions (15%), especially for events occurring in residential buildings, maintenance and repair works, small projects (i.e., $50,000 or less), and on Mondays. According to the decision tree analysis, the most important factor for determining the nature of the injury is the nonfragile injured body part, followed by injury caused by coating works. The decision tree also produced decision rules that provide an easy interpretation of the underlying association between the factors leading to incidents. The decision tree models developed in this study can be used to predict the nature of potential injuries for strategically selecting the most effective injury-prevention strategies.

Comparative Analysis of Human Traits and Tendencies: General vs. Specialty Contractor Project Managers

ABSTRACT Construction project managers (PMs) are critical team players in safeguarding project success. Construction organizations heavily rely on their PMs to inspire and motivate their teams to accomplish projects. However, labor turnover, changing demographics, and a shortage of skilled talent are common challenges in the industry. PMs transition between jobs in search of better opportunities. Labor turnover distresses project success, pressurizes team performance, and reduces organizational profitability. This study proposes using human traits assessments to evaluate the variations between job roles in construction. Understanding this sets a more positive work environment and improves teamwork, communication, and employee retention techniques. In assessing the differences between general contractor project managers (GC PMs) and specialty contractor project managers (specialty PMs), this study found that the traits and characteristics of individuals working in different roles can vary considerably. Significant differences in personality characteristics, emotional intelligence, and behavioral traits were identified. Construction companies may use human traits assessments to aid employee retention and talent development. Employees can better comprehend their work environments and smoothly transfer between roles in the industry as they learn the demands of the different job roles.

Developing a construct to measure contractor project manager performance competencies

PurposeConstruction organizations' investment in effective talent-development programs is a key strategy in attracting, developing and retaining staff. Such programs are especially important given the current challenges in the construction workforce, including labor shortages, an aging workforce, generational differences in the workforce, supply chain disruptions and the need to effectively train staff in the skills that are essential in a constrained labor environment. To address these challenges, this study proposes a performance measurement strategy that construction companies can use as input to design their talent development programs.Design/methodology/approachThe strategy intends to assess the performance of project managers and develop criteria that define categories of their performance, including the top performers' category. This enables construction organizations to provide each project manager with individualized training that addresses areas of weakness and in turn, develops the skills that correspond with being top performers. The proposed strategy was developed and tested by surveying the immediate supervisors of 187 project managers working for general and specialty contractors in the United States. Principal component analysis was used to develop a single performance construct from seven performance criteria.FindingsThis construct was used to organize the project managers into the categories of top, above-average and below-average performers. According to the findings, top-performing project managers have well-rounded skills in the areas of leadership, communication, technical proficiency and overall job knowledge.Practical implicationsThe outcomes of this study can help construction organizations focus their talent-development programs on the skills most associated with PMs being top performers.Originality/valueThis study provides construction organizations with a comprehensive performance-measuring construct to focus their talent-development programs on the skills most associated with top-performing project managers. Researchers can use this study as a foundation for further understanding how performance is related to various construction professions.

Could Hydraulic Fracturing Take Place for Asphalt Core in Embankment Dams through Possible Cracks in the Core?

Hydraulic asphalt concrete is virtually impervious. Hydraulic fracturing due to the generation of pore water pressure can be generally excluded for asphalt facings and asphalt cores in embankment dams. However, when some cracks and/or large voids exist in the asphalt core in dams, hydraulic fracturing could take place during reservoir impounding. Cracks and/or large voids may be caused by either earthquake shaking, large differential settlements during construction and operation, or poor construction quality. Therefore, asphalt specimens with either cracks of different depths or large air porosity were prepared, and a model test apparatus was developed to investigate the possibility of hydraulic fracturing. Model tests were conducted on cylindrical asphalt concrete specimens of 100 mm in diameter and 180 mm in height. The top boundary of the specimens was either prevented (restrained) from moving in the vertical direction or free to move (unrestrained). The model test results for asphalt concrete with cracks under unrestraint conditions were numerically back-analysed. The model test results indicated that the cracks in the asphalt concrete under the restraint conditions could experience an “open–close” progress with increasing water pressure. That suggested that if the asphalt concrete were long, low water pressure would trigger a fracturing through the cracks. Under the unrestraint conditions, low water pressure could cause the asphalt specimens with either cracks or large air porosity to fail. The extensional strains at failure were reduced, and the reductions depended on the magnitude of the crack depth or air porosity. Suggestions are given for designing the asphalt core dams to reduce the possibility of the occurrence of cracks and/or dilations in the core, especially for dams in unfavourable geological and topographical conditions. A specialty contractor is preferable to do the asphalt core job to rule out the possibility of a weak bond between the layers and an air porosity larger than 3.0% in the core.

Assessing the Crowding-Out Effects of Star Performers

The burgeoning literature on star performers has deep roots in and profoundly important implications for strategic human resource management. As the “war for talent” only becomes more concerning for HR scholars and managers, the importance of star performers – the uncommonly productive, innovative, seemingly indispensable sources of value-generating novel outcomes for organizations – has largely passed unquestioned. But stars in the human capital context exert complex influence across firm-level “solar systems.” Recent scholarly work has begun to shed light on the less desirable impacts of stars on their peers and organizations. Extending and enhancing this emergent stream, our study breaks new ground by developing and testing a crowding out theory of stars. Using a sample of 835 specialty contractors, we show that despite the many favorable impacts of star performers, the disproportionate attention and resources that flow to stars may actually leave firms worse off, especially among firms with star systems that emphasize hiring stars from outside the organization rather than developing talent internally. Our findings provide scholars and practitioners with new opportunities to reevaluate the potential role of remarkable individuals in the knowledge economy, thereby better illuminating the boundary conditions on how stars and star systems impact organizational outcomes.

Prefabrication supply chains with multiple shops: Optimization for job allocation

Prefabrication or off-site construction is a growing trend contributing to productivity improvements. It motivates specialty contractors and suppliers to operate multiple fabrication shops close to market regions, where a shop can produce and delivery prefabricated components in a timely fashion and at a minimal cost. Few quantitative models are available to assist companies with scheduling and allocation questions. This research utilizes optimization to answer these questions supporting the production planning in prefabrication supply chains. The paper presents an optimization model that seeks minimal cost while considering job demands and shop capacities. Computational results suggest that the model generates a lower-cost production schedule than the early due date (EDD) method. It also indicates that varying due dates cause changes in total cost. Moreover, this research supports decision-makers by analyzing the impacts of changing shop capacities regarding available machines. It provides further insight into construction supply chain management with multiple shops.

Analysis of Mutual Market Entry Level between General and Specialty Contractors according to Abolishing the Regulation of Business Area

Analysis of Mutual Market Entry Level between General and Specialty Contractors according to Abolishing the Regulation of Business Area

Life cycle cost savings analysis on traditional drainage systems from low impact development strategies

Areas that are covered with natural vegetation have been converted into asphalt, concrete, or roofed structures and have increased surface impermeability and decreased natural drainage capability. Conventional drainage systems were built to mimic natural drainage patterns to prevent the occurrence of waterlogging in developed sites. These drainage systems consist of two major components: 1) a stormwater conduit system, and 2) a runoff storage system. Runoff storage systems contain retention basins and drywells that are used to store and percolate runoff, whereas conduit systems are combination of catch basins and conduit pipes used to collect and transport runoff. The construction of these drainage systems is costly and may cause significant environmental disturbance. In this study, low impact development (LID) methods that consist of extensive green roofs (GRs) and permeable interlocking concrete pavements (PICPs) are applied in real-world construction projects. Construction project documents were reviewed, and related cost information was gathered through the accepted bidding proposals and interviews of specialty contractors in the metropolitan area of Phoenix, Arizona. Results indicate that the application of both LID methods to existing projects can save an average of 27.2% in life cycle costs (LCC) for a 50-year service life and 18.7% in LCC for a 25-year service life on the proposed drainage system, respectively.

BIM의 효율적 활용을 위한 전문협력업체 조기참여 필요성과 적용 방안

BIM의 효율적 활용을 위한 전문협력업체 조기참여 필요성과 적용 방안

Restructuring the Organ Procurement and Transplantation Network contract to achieve policy coherence and infrastructure excellence.

The Organ Procurement and Transplantation Network (OPTN) went up for competitive bid again this year, yet this contract has been held by only 1 entity since its inception. The OPTN's scope has grown steadily, and it now embraces several disparate missions: to operate the computing and coordination infrastructure that maintains waitlists and makes organ offers in priority order, to regulate transplant centers and organ procurement organizations, to follow and protect living donors, and to decide organ allocation policy in concert with the many voices of the transplant community. The contracting process and performance work statement continue to discourage both innovative approaches to the OPTN and competitive bids outside of United Network for Organ Sharing (UNOS), with evaluation criteria that either disqualify or strongly disadvantage new applicants. The performance work statement also emphasizes bureaucratic tasks while obligating the OPTN contractor to the specific committee structure that has impeded decision-making and tended to preserve the status quo in controversial matters. Finally, the UNOS computing infrastructure is antiquated and requires months to years to implement small changes. Restructuring the OPTN contract to separate the information technology requirements from the policy/regulatory responsibilities might allow more nimble and effective specialty contractors to offer their capabilities in service of the national transplant enterprise.

Types and factors affecting injury rates of mechanical contractors.

In the United States, about 38,000 cases of nonfatal workplace injuries were reported in 2015, in the category of 'mechanical work' (plumbing, heating, and air conditioning); this is nearly identical to the number of cases reported under 'building construction'. This paper analyzes the types and rates of injuries and illnesses of mechanical contractors of southern Nevada, including the nature of the injuries and illnesses, body parts affected by injuries, causes of injuries, and factors affecting the injury rates. To obtain data, a survey consisting of questions regarding the number of injuries and types of injuries was conducted with 31 mechanical contractors of southern Nevada involved in plumbing, piping, heating, refrigeration, and air conditioning. The injury rate for larger mechanical contractors (n = 16), in terms of number of employees and annual revenue, was significantly lower than for smaller mechanical contractors (n = 15). Mechanical contractors who worked on residential buildings (n = 13) had significantly higher rates of injuries than those involved with industrial (n = 7) or commercial buildings (n = 10). Results showed that sprains and strains (31%) were dominant injuries, and the major causes were from parts and materials (39%), hand tools (16%), contact with objects (14%), and falls (7%). The study concluded that the injury rate for these mechanical contractors was found to be higher than that reported by the Occupational Safety and Health Administration for specialty trade contractors.

Legislative Control based on Reconsideration of Legal Character for Government Procurement - Contracting with a Team Consisting of General Contractor & Specialty Contractor -

Legislative Control based on Reconsideration of Legal Character for Government Procurement - Contracting with a Team Consisting of General Contractor & Specialty Contractor -

Binder threshold approach to predicting soil mixing strength in organic soils

Organic soil stabilisation by mixing with cementitious binders, called soil mixing, has traditionally been problematic due to unpredictable strength gains. Anecdotally, practitioners and specialty contractors recognise a notable increase in the required amounts of binder relative to inorganic soil mixing experiences but this too has been unpredictable. This paper discusses the results from laboratory and field case studies conducted to better estimate the amount of binder required for organic soil mixing, which makes design strength predictions possible.

Mobile application tool for individual maintenance users on high-rise residential buildings in South Korea

Since 1980’s, the rapid economic growth resulted in so many aged apartment buildings in South Korea. Nevertheless, there is insufficient maintenance practice of buildings. In this study, to facilitate the building maintenance the authors classified the building defects into three levels according to their level of performance and developed a mobile application tool based on each level’s appropriate feedback. The feedback structure consisted of ‘Maintenance manual phase’, ‘Online feedback phase’, ‘Repair work phase of the specialty contractors’. In order to implement each phase the authors devised the necessary database for each phase and created a prototype system that can develop on its own. The authors expect that the building users can easily maintain their buildings by using this application.

Impact of Team Integration and Group Cohesion on Project Delivery Performance

AbstractThe architecture, engineering, and construction (AEC) industry is often criticized for its fragmented approach to project delivery. Traditional procurement and contracting intentionally serves to isolate designers from contractors to provide checks and balances, but limits opportunities for collaboration. This research presents a structural modeling approach to studying the role of integration in the performance of building construction projects. A sample data set of 204 completed projects was collected to compare cost, schedule, and quality performance under different delivery methods. Integration of project teams was proposed and tested in the form of two latent constructs—team integration and group cohesion—that mediate the link between delivery methods and performance. More integrated teams interacted with more participants from all levels of the building construction process, from designers to specialty trade contractors. These interactions included design charrettes, joint goal setting, and ...

Exploring performance of the integrated project delivery process on complex building projects

Many building projects do not meet owners' performance expectations. Integrated project delivery (IPD) has emerged as a new delivery system with the potential to provide better performance through more supply chain integration. However, there is a knowledge gap surrounding how project delivery systems, IPD in particular, affect supply chain relationships and potential project performance. To fill this gap, we applied a simulation method, General Performance Model (GPM), to assess the interactions between numerous project delivery variables and compare potential performance between delivery systems. This study presents a GPM analysis of a complex hospital project and based upon cross-impact assessments by owners, architects, constructors, and specialty contractors from the building industry. The results found the most influential drivers of project delivery performance to be communication, alignment of interest and objectives, team working, trust, and gain/pain sharing. The performance of the supply chain was found to drive the project delivery performance.

Exploration of Team Integration in Spanish Multifamily Residential Building Construction

AbstractProject delivery team integration generally involves early involvement of general contractors and key specialty contractors in the design process. Team integration has been found to improve an owner’s probability of success. However, during difficult economic times, owners can forego early team involvement and move toward low bid procurement to take advantage of competitive markets. This study explores the performance of integrated teams in the Spanish multifamily building construction market in light of the 2007 financial crisis. After conducting structured interviews of 31 residential building projects with the owner and main contractor of each one of them, this study identified eight projects for in-depth case studies. These eight case studies represented the best performing, worst performing, and atypical cases. The results show that Spanish building owners experience higher success by developing integrated teams. This integration begins with how the owner organizes the team for success (i.e.,...

Managing information complexity using system dynamics on construction projects

The increase in e-commerce, the digitisation of design data and the interchange and sharing of information have made the construction sector more reliant upon IT infrastructure and systems. The design and production process is complex, dynamic, interconnected and dependent upon greater information mobility, requiring seamless exchange of data and information in real time. Small- and medium-sized enterprises (SMEs), in particular, specialty contractors, can utilise cost-effective collaboration technologies, such as cloud computing using software as a service, to help in the effective transfer of information and data. The system dynamics (SD) approach gives a better understanding of the dynamics of complex systems. SD methodology is used as a modelling and analysis tool to understand and identify the key drivers in the absorption of cloud computing for SMEs. The aim is to determine how the use of SD can improve the management of complexity of information flow, leading to improved performance for SMEs. SD is shown to be a viable tool to manage information complexity using cloud computing for performance improvement in construction.

An Assessment of the Asphalt Shingle Roofing Process for Residential Buildings

Asphalt shingle roofing is performed by specialty contractors in the construction industry with the roofing crew performing tasks in different areas on the roof simultaneously. While asphalt shingle roofing materials have improved, the roofing construction process has not changed significantly over the past 70 years.This paper describes the process, factors that affect the productivity of the workers, and methods for calculating productivity in terms of man-hours worked and cost per unit output. Safety is also a concern in roofing. While falls from roofs are a major cause of injuries on the construction job site, other injuries common to roofers include sprains and strains to the back, knees and ankles. The trend of constructing steep roofs, common in Texas high end residential homes, are implicated in these injuries. Safety plans and worker safety climate are low priorities for financially strapped construction companies. Designing out the hazard would be more effective than Personal Protective Equipment (PPE) in preventing accidents in the roofing industry.The paper concludes that research and development are needed to improve roofing construction methods to provide a safe and healthy environment for the worker and reduce costs of construction.

IPA 기법을 활용한 전문건설업체 종사자의 직무별 역량요인 분석

Abstract : Recently, the construction policy is rapidly changing and construction project becomes larger and more complex. Specialty contractors are in charge of the actual construction work, but they are considered to have low competence level. To strengthen competence of specialty contractors’ employees, above all, it is essential to evaluate and to analyze the competence factors level for specialty contractors’ employees. However, there is no in-depth research on competence factors level for specialty contractors. Therefore, the purpose of this study is to analyze the competence factor in order to find the high priority factor. The result of this study can be utilized for development of effective educational program for enhance specialty contractors’ competence. Keywords : Specialty Contractors’ Employees, Competence Factors, Competence Assessment, Importance-Performance Analysis(IPA) * Corresponding author: Oh, Chi-Don, Korea Research Institute of Mechanical Facilities Industry(KRIMFI), Seoul 135-951, KoreaE-mail: chidon@krimfi.re.krReceived April 15, 2015: revised May 27, 2015 accepted August 6, 2015