CONTENT

Editorial

1. K. W. Andy NG, Andrew Price:
Causes Leading to Poor Site Coordination in Building Projects

2. Antonios Panas, John - Paris Pantouvakis:
An empirical framework for the performance-based evaluation of health and safety's contribution to sustainable construction

3. Nikolaos Fragkakis, Sergios Lambropoulos, John - Paris Pantouvakis:
A cost estimate method for bridge superstructures using regression analysis and bootstrap

4. Čenek Jarsky:
On computer Modelling of the Building Process in Construction Planning and Management

5. Maria Kozlovska, Zuzana Strukova, Alena Tažikova:
Access to construction time objectiveness

6. Shaohua Jiang, Miroslaw J. Skibniewski, Yongbo Yuan, Chengshuang Sun:
Ultra-Wide band technology applications in construction: a review

1. K. W. Andy NG, Andrew Price:


Causes Leading to Poor Site Coordination in Building Projects

Abstract:
It is a common practice for the main contractors of Hong Kong building projects to sublet most of the works to subcontractors. However, most of the subcontractors complain that they are unable to perform to their full capacity due to poor coordination of temporary works and access road to work places etc. Eighteen common site coordination problems and sixteen essential causes to the problems were identified from literature and advices from experienced industrial practitioners. The causes were grouped into three categories: staffing related causes; technical related causes; and management system related causes. The contribution, frequency of occurrence and
aggregated importance of the causes on the quality of main contractors’ coordination during the construction stage were ranked through a questionnaire survey. Unclear job duties was found to be the most important cause. The results of the survey established that the most important causes were mainly associated with management systems, especially communications, rather than staffing or technical related factors.

Keywords:
Subcontracting, site coordination problems, performance

                                                                                                                                                               

2. Antonios Panas, John - Paris Pantouvakis:


An empirical framework for the performance-based evaluation of health and safety's contribution to sustainable construction

Abstract:
The current approach to construction health and safety (H&S) and sustainable construction underestimates the role of production practices and focuses mainly to the formulation of general guidelines and best-practice policies. This paper aims at exploring the role of H&S in achieving sustainability for projects from a different perspective. A conceptual model is formulated, enabling the integration of H&S and sustainability under the prism of productivity. An empirical framework is subsequently presented to evaluate the relationship workers’ health, as expressed by their thermal comfort and environmental parameters, in productivity estimation. A structured data elicitation approach is established for conducting valid field measurements. Process mapping and simulation-based analysis is used for the comparative analysis of productivity forecasting models. An exemplar investigation of formwork operations illustrates the applicability of the proposed approach. The main conclusion from the study is that the implementation of the empirical framework enables the creation of foresight in planning construction operations by analysing productivity variations compared to baseline estimates. Thus, the effect of H&S on performance is quantified and the expected productivity variability can be evaluated. It is believed that such an approach provides a more realistic representation of construction operations and improves the accuracy of the estimating process.

Keywords:
Construction, health, productivity, safety, thermal comfort

                                                                                                                                                                

3. Nikolaos Fragkakis, Sergios Lambropoulos, John - Paris Pantouvakis:


A cost estimate method for bridge superstructures using regression analysis and bootstrap

Abstract:
Preliminary cost estimates rely on the conceptual design of the project and use only basic design technologies. Although they present the lowest expected accuracy, they are often used by key people involved in the construction process, thus playing a significant role. Bridge construction has increased over the last years, often exhibiting substantial overruns above estimated costs. To overcome this problem, it is crucial for the decision makers to have an early estimate of the final cost based on previous experience. This paper addresses the need for easy-to-use and reliable cost estimates during the early stages of projects for bridge superstructures, presenting a major impact on the total bridge construction cost. It proposes a conceptual cost estimate method that involves the estimation of both the material quantities and the relevant costs. It describes the development of prediction models for the material quantities of concrete and reinforcing and prestressing steel for three major bridge deck construction methods using regression analysis, while a bootstrap resampling method is used to produce estimate ranges. The material estimating models rely on the development of a database after collecting actual data from a large sample of modern bridges. The major assumptions underlying the correct application of the regression methodology were tested, and necessary adjustments were made. The proposed conceptual cost-estimating methodology uses information known before detailed plans are developed to provide fast and reliable results that can be very useful in the early stages of a road project.

Keywords:
Construction costs; Bridges; Estimation; Regression analysis; Bootstrap

                                                                                                                                                                

4. Čenek Jarsky:


On Computer Modelling of the Building Process in Construction Planning and Management

Abstract:
The paper describes the main principles and results of the integrated cost estimation and project management microcomputer expert system developed in the last years on the base of the spatial, technological and time analysis of the building process with use of the methodology of the construction technology design. This expert system is based on quick modelling of the building process by use of typical network diagrams, which are prepared in advance, created by an original construction technology network diagram method. The typical network diagrams can be modified according to the spatial conditions of a certain building and to the amount of construction works and materials. Thanks to the database of construction processes and to the typical network diagrams the model of the building process including the cost assessment can be made about 50 times quicker than by use of current cost estimation or project management systems, quality assurance checklists, environmental plans and plans of the safety at work included.

Keywords:
construction technology, building process model, network analysis, project management

                                                                                                                                                                

5. Maria Kozlovska, Zuzana Strukova, Alena Tažikova:


Access to construction time objectiveness

Abstract:
One from important requirements of successfully managed building project is determining of contract parameters (mainly time and costs) already in project preparation phase. Such consideration requires a significantly objectified analysis of both influential parameters. Our research is focused especially to risks resulting from construction process acceleration. This phenomenon is in construction evident for several years. The construction processes parameters allow the time regulation of every operation. For all that the contractor must consider fairly, by what measures and at which “rate” he is able to perform the contract construction time. On the other hand the client must accept objective time possibilities of construction and reconciliation of time parameters between client and contractor must occur. The paper presents an approach to reconciliation of construction time parameters between client and contractor and affords opportunity to model the trend of contract construction times in various projects segments. The spatial and organizational possibilities of construction process development in individual projects segments determines the measures for performance of construction time similar to contract construction time as more as possible. Fifty five construction projects were analyzed. Considering the heterogeneousness of their spatial and technological structure, these projects
were divided to following segments: multifunctional buildings, shopping centres, production plants and residential buildings. Trends of contract construction time and simulated measures impacts (construction time shortening) were derived for all the segments. The paper presents a possible approach to objectification of building time parameters. The point of the research consists in estimation of expected time limits for intended construction that are necessary for client as well as for forward contractor.

Keywords:
construction time performance, construction time shortening, project decision, regression analysis

                                                                                                                                                                

6. Shaohua Jiang, Miroslaw J. Skibniewski, Yongbo Yuan, Chengshuang Sun:


Ultra-Wide Band technology applications in construction: a review

Abstract:
This paper explores the state-of-the-art research and development of UWB applications in many sectors, including the construction industry. This paper will provide insights into the technology for the uninitiated reader without involving detailed technological and arithmetic aspects of UWB. To do so, this paper first introduces the key concepts behind UWB and provides a brief historical perspective. It then summarizes the UWB’s technical features which enable it so popular in industry. Finally, a number of UWB application examples in many sectors, including construction, are presented to analyze and highlight the impact on the industry performance. UWB technology is expected to become a very important component and have profound impact in ubiquitous computing in the near future.

Keywords:
Ultra-Wide Band; frequency range; receiver; tracking;
sensing