Due to the loss of financial resources and the need to optimize projects, academics, politicians and the construction industry have become increasingly aware of the challenges presented by the frequent time and cost overruns and reduced quality level of construction projects. The purpose of this study is to analyse the factors that project managers experience as having the greatest effect on time, cost and quality, and to discover whether the factors' effects are significantly different from each other. A questionnaire with 26 factors identified from interviews was sent to the full population of publicly employed project managers. Factors were ranked by using the relative importance index and tested for significant differences by applying the Friedman´s test with the Wilcoxon´s test as post-hoc analysis. From the analysis, the most affecting factor associated with time was found to be unsettled or lack of project funding. For the cost related factor, errors or omissions in the consultant material, was the most important. Finally, the quality related factor was errors or omissions in construction work. The main conclusion of this research showed that the project schedule, budget and quality level are significantly different affected. The project manager therefore cannot handle such critical issues by only focusing at schedule or budget related complication, either can the project manager assume that time, cost and quality are equally affected.

Purpose A construction project traditionally involves a variety of participants. Owners, consultants, and contractors all have diverse opinions and interests, but they all seek to ensure project success. Success is habitually measured as performance output regarding cost, time, and quality. Despite previous research mapping the success and failure factors, construction managers seem to have difficulty in attaining success. To provide clearer guidance on how to fulfill success criteria, the purpose of this paper is to identify the underlying factors that affect performance and thus project success in construction processes. Design/methodology/approach A questionnaire survey based on a literature review provided 25 key process factors divided into five key categories. Based on the responses from commonly involved construction parties, the factors were ranked and tested for significant differences between the parties. Findings The top five most important process factors were found to relate to the sharing of knowledge and communication. Moreover, testing the ranking for significant differences between owners, consultants, and contractors revealed five differences. The differences related to the interpretation and importance of trust, shared objectives, project coordination, and alternative forms of coordination. Originality/value All respondents identify improved knowledge sharing and communication as the key to improved cost, time, and quality performance and are therefore the areas where construction managers need to focus their resources. Thus, improved experience sharing and communication will increase the likelihood of project success, through improving competences, commitment, and coordination.

For decades construction labour productivity has been stagnated or declining. Changing this issue requires new knowledge on the labour-intensive construction production system. The work sampling method was applied to collect data from 3 renovation construction production systems. It quantifies observations of on-site work and enables deep analyses of how time is used. The analysis revealed that the renovation projects had a baseline of value-adding-work (VAW) time on 29.5%. It further identified 5 system behaviours outlining how VAW and Non-Value-Adding work (NVAW) time behaves. The new knowledge of how both VAW and NVAW time behaves advances knowledge on how time is wasted in construction projects and opens new branches of future research. The findings are furthermore of potential use to industry professionals who work with process improvement in renovation projects because they provide, among others, answers to how targets can be defined for both VAW and NVAW.

No abstract

Labor productivity in construction has fallen behind other industries in most of the world and has declined continuously for decades in the US. To change this, the construction industry needs to know where to focus. This research aims to show how important craftsmen efficiency is for national construction labor productivity (CLP) development. Statistical analysis was used to compare craftsmen efficiency and CLP data from North America (NA) in the period 1972-2010. Craftsmen efficiency data were extracted from published work that measured direct work (DW) through work sampling, and CLP data were extracted from national databases. A statistically significant relationship between DW and CLP was established. This revealed that adding 36 seconds of DW to every work hour could yield a yearly return of 5.4 billion USD to the NA gross domestic product (GDP). Results show that more focus on activity and project level efficiency is crucial for changing the trends of national CLP. Industry leaders and policy makers now have a solid foundation for taking corrective actions for an industry plagued by low productivity.

Construction sites are dominated by chaos and complexity, enforcing challenging conditions for establishing reliable and robust schedules that are easy to observe. The consequence is a large amount of delayed activities that again results in an unreliable schedule. Last planner system (LPS) was introduced as a production planning and control system to increase the reliability of scheduling task. By focusing on the removal of constraints, the LPS has successfully decreased the number of delayed activities. To further decrease delays, this research investigates the causes for delays at three construction cases. In total, 5424 scheduled activities were followed, whereof 1450 were delayed. The delayed activities were, besides the unidentified ones, categorized into 11 different categories and a statistical test of means was performed. The research revealed six often-occurring causes to delay: connecting work, change in work plans, workforce, external conditions, material and construction design. Furthermore, the study revealed five seldom-occurring causes to delay: space, equipment, rework, unexpected conditions, and safety. The findings have been structured in accordance to the preconditions used in the LPS theory. Therefore, the results can directly be applied to the making-ready process and used as guidance of where to intervene in attempt to reduce future delay.

Mass customization is a manufacturing paradigm that enables customized and personalized design at a cost near mass production. Mass customization's ability to lower unit cost, increase quality, and shorten project duration for customized offerings is considered highly relevant for tomorrow's house building industry. Therefore, through a literature review, this research investigates state-of-the-art in mass customization in the house building industry from four perspectives: (1) mass customization in the house building industry, (2) modular and off-site construction, (3) construction supply chains, and (4) customer satisfaction. It is concluded that a great potential exists for applying mass customization in the house building industry. However, despite its potential, research on mass customization in the house building industry is sparse. In particular, research on developing the solution space and choice navigation tools is limited in this industry.

Abstract:The occurrence of variation orders (VOs) in the construction industry is a regular trend all over the world. Hydropower projects are no exception, and it is difficult to find a hydropower project in Pakistan that does not experience VOs. The current research investigates the causes and impacts of VOs in mega hydropower projects using case studies of three mega hydropower projects in Pakistan. The results illustrate that errors and omissions in design, changes in scope and changes in design were among the three top contributing factors to VOs in hydropower projects that resulted in time and cost overruns. Because of VOs, the time overrun is 20%, and the cost overrun is 31% with respect to the planned time and cost of the project. Based on this research, the study recommends measures to curb the causes and impacts of VOs to optimise the construction process of mega hydropower projects.