C. M. Tam

An application of the Internet-based project management system

Abstract The great advance in information technologies (IT) and the availability of a wide range of software in recent years have brought many changes in the construction industry. The Internet, a new member of IT, offers a medium with new opportunities to manage construction projects. This paper describes an Internet-based project management system called “Total Information Transfer System” (TITS). TITS comprises six major functions including data exchange, information exchange, Internet chat, live video-cam, search engine and auxiliary services. TITS is demonstrated for project monitoring with a real-life project.

Site pre-cast yard layout arrangement through genetic algorithms

The use of modular construction has gained wide acceptance in the housing sector. Standardized modular units are often pre-cast on site. The establishment of site pre-cast yard, in particular arranging the pre-cast facilities within the compound, presents real challenge to site management. This complex task is further aggregated with the involvement of several resources with different transport cost. A GA-model is developed for the search for a near optimal layout solution. The fitness function is to minimize the total transport cost for a pre-determined daily output. The use of the model is illustrated by an example. When compared with the best solution within the initial population, 18.45% reduction in cost for resources flow was achieved by the near optimal layout arrangement arrived at the 673rd trial. It is also suggested that the model can be extended to other layout problems such as warehouse and production line.

Relationships between business factors and performance in internationalization: An empirical study in China

Purpose – While internationalization of firms can be a source of growth in profitability, it can also result in huge losses due to the risky internationalized environment. Success in the home countries does not guarantee success internationally. The objective of this study is to identify the main business factors affecting performance of firms in the process of internationalization.Design/methodology/approach – Ten business factors have been selected to investigate their relationship with the business performance in the internationalization process of Chinese manufacturing firms. The ten business factors are transformed into four dimensions (principal factors) using the method of factor analysis. Using the categorical regression method, relationships between return on assets (ROA) and the four dimensions extracted are examined.Findings – The findings reveal that marketing capability of firms plays the most important role in improving performance of firms that embrace internationalization.Research limitati...

Physio-chemical reactions in recycle aggregate concrete.

Concrete waste constitutes the major proportion of construction waste at about 50% of the total waste generated. An effective way to reduce concrete waste is to reuse it as recycled aggregate (RA) for the production of recycled aggregate concrete (RAC). This paper studies the physio-chemical reactions of cement paste around aggregate for normal aggregate concrete (NAC) and RAC mixed with normal mixing approach (NMA) and two-stage mixing approach (TSMA) by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Four kinds of physio-chemical reactions have been recorded from the concrete samples, including the dehydration of C(3)S(2)H(3), iron-substituted ettringite, dehydroxylation of CH and development of C(6)S(3)H at about 90 degrees C, 135 degrees C, 441 degrees C and 570 degrees C, respectively. From the DSC results, it is confirmed that the concrete samples with RA substitution have generated less amount of strength enhancement chemical products when compared to those without RA substitution. However, the results from the TSMA are found improving the RAC quality. The pre-mix procedure of the TSMA can effectively develop some strength enhancing chemical products including, C(3)S(2)H(3), ettringite, CH and C(6)S(3)H, which shows that RAC made from the TSMA can improve the hydration processes.

Competitive priorities of manufacturing firms for internationalization: an empirical research

Purpose – The purpose of this research is to identify the competitive priorities of the manufacturing firms in their internationalization efforts.Design/methodology/approach – A structured questionnaire survey is conducted involving 569 manufacturing firms in China. The competitive priority in internationalization efforts is gauged by combining the degree of emphasis of manufacturing firms on a certain factor over the past three years and the level of improvement of the factor into an index.Findings – It is found that “technology level”, “cost control”, and “brand consciousness” are the top three most important factors affecting the competitiveness of internationalization of manufacturing in China. The three bottlenecked factors that impede internationalization include “Internationalization business experience”, “Financing capacity” and “Senior managers with management know‐how”.Practical implications – With the rapid development of economy globalization, firms in the Chinese manufacturing sector have beg...

Combinatorial optimal design of number and positions of actuators in actively controlled structures using genetic algorithms

In this paper, the optimal design of the numbers and positions of actuators in actively controlled structures is formulated as a three-level optimal design problem. Features of this design problem such as discreteness, multi-modality and hierarchical structure are discussed. A two-level genetic algorithm (TLGA) is proposed for solving this problem. The concept, principle and solution process of the TLGA are described. A case study is presented, in which a building is subjected to earthquake excitation and controlled by active tendon actuators. The results of this study show that: (1) the design problem for optimizing number and configuration of actuators simultaneously in actively controlled structures has the features of non-linearity, mixed-discreteness and multi-modality; (2) a three-level design model can give a reasonable description for this kind of design problem; (3) TLGA is an effective algorithm for solving the combinatorial optimization problem.

Comparative study of artificial neural networks and multiple regression analysis for predicting hoisting times of tower cranes

Abstract This paper aims to develop a quantitative model for predicting the hoisting times of tower cranes for public housing construction using artificial neural network and multiple regression analysis. Firstly, based on data collected from crane operators and site managers in seven construction sites, the basic factors affecting the hoisting times for tower cranes are identified. Then, artificial neural networks (ANN) and the multiple regression analysis (MRA) are used to model the hoisting time, and from the results, the neural network model and the multiple regression model of hoisting time are established. The modeling methods and procedures are explained. These two kinds of models are then verified by data obtained from an independent site, and the predictive behaviors of the two kinds of models are compared and analyzed. Furthermore, the predictive behaviors of the neural network model are also investigated by a sensitivity analysis. Finally, the modeling methods, predictive behaviors and the advantages of each model are discussed.

Overcoming Barriers to Innovation in SMEs in China: A Perspective Based Cooperation Network

Abstract Innovation has been one of the key drivers of sustainable competitive advantage for small and medium-sized enterprises (SMEs). On the basis of a survey sample of 188 Chinese manufacturing SMEs, this paper explores barriers, cooperation networks and policy requirements in innovation for SMEs. This paper reveals that the ‘lack of technical experts’ is the most important barrier; the ‘customer’, the most important cooperation partner; and the ‘preferential tax policy’, the most favorable policy in innovation for SMEs. These findings reveal that many Chinese SMEs have difficulties in achieving successful innovation. Therefore, policies should be made based on internal and external constraints to facilitate innovation of SMEs, and varied depending on the size as well as the mode of ownership of firms.

Prediction of hoisting time for tower cranes for public housing construction in Hong Kong

Material transportation for high-rise building construction relies heavily on tower cranes. Hence the proper use of tower cranes is of paramount importance for high-rise residential building construction. In planning and monitoring crane usage in Hong Kong, a schedule is usually prepared to coordinate hoisting operations. Apart from that, little research in optimizing crane usage has been carried out previously, except on operation cycle times, e.g. concreting using a crane and skip and formwork erection. Allocation of time for the hoisting schedule is based on the planners and operators experience. The accuracy of the hoisting schedule for crane dominated construction works has significant effects on the materials supply and on concreting operations. Imbalance in the allocation of crane usage for subcontractors may lead to conflicts between trades and idling of workers due to a shortage of materials. Although planners understand that the load hoisting time is proportional to hoisting height and other factors, floor construction cycles usually, for simplicity, are assigned to be constant six day, eight day or ten day cycles without making the necessary compensation for the longer hoisting times for upper floors. The prediction of hoisting times is of great importance to planners to ensure the accuracy of the construction schedule for crane dominated construction. This paper describes the derivation of a mathematical model to predict the hoisting times for a tower crane for public housing construction. Work measurement is used to collect hoisting times data for analysis. Twelve factors considered to influence hoisting time are identified for the model. Multiple regression models are built for predicting supply hoisting times and return hoisting times. The effects of the variables on hoisting time are reviewed. Estimated hoisting times calculated from the models are compared with actual hoisting times, and a worked example illustrating the application of the models is presented.

Performance assessment scoring system of public housing construction for quality improvement in Hong Kong

In an attempt to improve the quality management of public housing construction in Hong Kong, the Hong Kong Housing Authority has implemented the performance assessment scoring system (PASS) as a mechanism for evaluating the effectiveness of a contractor’s ability to deliver projects to specified standards. This was seen as an effective assessment and incentive system for promoting continuous quality improvement. However, the analysis of PASS scores has indicated that the general level of quality has not been significantly improved. Based on the analyses of PASS scores and contractor performance, the shortfalls of the system are explored and some recommendations to realize the vision of continuous quality improvement in public housing construction are proposed.