O. O. Ugwu

Causes of delay and cost overruns in Nigerian construction projects

Abstract The subject of project management in developing countries is addressed, with a focus on Nigeria, one of the largest and most populated countries in Africa. The causes of delay and cost overruns are investigated by examining data relating to construction projects. After a brief introduction to the overall economy, an analysis is given of recently completed highway projects in the country. This points to substantial cost variations relative to the initial contract, and excessive project overruns, for neither of which is there much explanation in status reporting. A brief review then follows of contractual systems and project financing arrangements currently in operation. The results of a questionnaire survey carried out in 1992 with around 50 construction personnel from contractor, consultant and client organisations in Nigeria are then presented. The conclusions suggest that there could be better phasing of contracts, and a wider variety of contracts could be used. Overruns are attributed to finance and payment arrangements, poor contract management, materials shortages, inaccurate estimating, and overall price fluctuations. Recommendations are given on how project management could be improved in developing countries such as Nigeria by appropriate action being taken at both the conceptual and detailed planning stages of projects. Wider action is further called for at both government and international level.

Sustainability appraisal in infrastructure projects (SUSAIP): Part 1. Development of indicators and computational methods

Abstract The process of translating strategic sustainability objectives into concrete action at project-specific levels is a difficult task. The multi-dimensional perspectives of sustainability such as economy, society, environment, combined with a lack of structured methodology and information at various hierarchical levels, further exacerbate the problem. This paper (Part 1 of a two-part series) proposes an analytical decision model and a structured methodology for sustainability appraisal in infrastructure projects. The paper uses the ‘weighted sum model’ technique in multi-criteria decision analysis (MCDA) and the ‘additive utility model’ in analytical hierarchical process (AHP) for multi-criteria decision making, to develop the model from first principles. It discusses the development of key performance indicators encapsulated within the analytical model. It concludes by discussing other potential applications of the proposed model and methodology for process automation as part of integrated sustainability appraisal in infrastructure design and construction. Part 2 uses a case study to demonstrate the model application in infrastructure sustainability appraisal at design stages. The paper also discusses the challenges for sustainability research, and gives recommendations.

Collaborative design of structures using intelligent agents

The construction industry has a long tradition of collaborative working between the members of a construction project team. At the design stage, this has traditionally been based on physical meetings between representatives of the principal design disciplines. To aid these meetings, the information and communications technologies that are currently available have been utilised. These have yielded some success but are hampered by the problems posed by the use of heterogeneous software tools and the lack of effective collaboration tools that are necessary to collapse the time and distance constraints, within which increasingly global design teams work. In particular, there are very few tools available to support distributed asynchronous collaboration. Distributed artificial intelligence, which is commonly implemented in the form of intelligent agents, offers considerable potential for the development of such tools. This paper examines some of the issues associated with the use of distributed artificial intelligence systems within the construction industry. It describes the potential for the use of agent technology in collaborative design and then goes on to present the key features of an agent-based system for the collaborative design of portal frame structures. An example is presented to demonstrate the working and benefits of the prototype system, which makes a significant contribution by allowing for peer to peer negotiation between the design agents.

Negotiation within a multi-agent system for the collaborative design of light industrial buildings

This paper is a review of intelligent agents with respect to their use within the Agent-Based Support for The Collaborative Design of Light Industrial Buildings (ADLIB) project. In the ADLIB project, the core objective is to develop a multi-agent system (MAS) framework for the representation of activities and processes involved in collaborative design of light industrial buildings. This includes the planning and fabrication of steel structural components. ADLIB intelligent agents are concerned with modelling action and knowledge in a collaborative environment. The design process that ADLIBs agents are trying to automate is the interaction and negotiation between specialist design team members. Each team member with a different area of expertise will be primarily concerned with his own area of interest. This paper starts with an introduction to intelligent agents. It then moves on to a discussion of agent classification systems and negotiation theories and their applications in MAS. The last section analyses the needs of agents within the ADLIB project. A negotiation protocol and strategy are then presented.

Negotiation in a multi-agent system for construction claims negotiation

Negotiation is an important approach for agents to co-operate and reach agreement in multiagent systems (MAS). Different negotiation theories and models have been deployed in a variety of applications. This paper is concerned with the applicability of these theories to the domain of agent-based construction claims negotiation. The peculiarities of this domain are highlighted and the approach adopted in the development of a multi-agent system for construction claims negotiation (MASCOT) described. Of particular interest is the integration of Zeuthens bargaining model with a Bayesian learning mechanism, which addresses the characeristics of the construction claims negotiation. Examples are presented to demonstrate the impact of various negotiation approaches on the conduct and outcome of construction claims negotiations.

The development of a multi-agent system for construction claims negotiation

Negotiation is an important stage in construction claims management process. Unfortunately, most construction claims negotiations are conducted inefficiently due to various reasons. The recent development of multi-agent systems provides an innovative approach to facilitating various negotiations. This research has developed a multi-agent system for construction claims negotiation (MASCOT) to resolve the inefficiency problem. This paper discusses the key points of the MASCOT model. Of particular interest is the computer implementation of the developed MASCOT model using the ZEUS agent building toolkit.

A multi‐agent system for distributed collaborative design

Presents a multi‐agent system (MAS) for collaborative design in the construction sector. The system is intended to form a basis for integrating the often distributed cross‐functional activities that characterise collaborative design in construction. The MAS supports interaction and negotiation between the different agents that represent various participants that are usually engaged in a typical collaborative project design. The system is composed of different agents that provide services within the MAS environment. While some of the support services are provided by the agent platform, task agents that represent various functional disciplines undertake the real design activities. Describes details of the MAS, which simulates and demonstrates peer‐to‐peer interaction, communication and negotiation between the design agents in a collaborative design space. Also highlights important issues in MAS development and makes recommendations on how to improve collaborative design in construction using the MAS paradigm.

Empowering collaborative decisions in complex construction project scenarios

Diverse construction project stakeholders demand “fully‐informed” and well‐balanced decisions that target multiple objectives appropriately. This paper introduces initiatives into the development of a cluster of information and communication technology‐artificial intelligence supported empowerment systems and sub‐systems. Examples presented include conceptual models and/or descriptions of: the framework of an over‐arching management support system (MSS); multi‐agent support for improved collaborative working in: design development and relationally integrated supply chain management; and web‐based quality management.

Modelling construction material logistics system with stochastic Petri nets

Purpose – The purpose of this paper is to examine the potential of applying Petri nets to improve construction material logistics analysis and modelling.Design/methodology/approach – The characteristics of construction logistics are unveiled by analysing the existing practices of logistics management. In views of the dynamic nature of construction logistics problem, a stochastic Petri nets (SPNs) approach is proposed to tackle the time‐evolution property. Using a simulation package called PetriTool™ a simulation model is developed. Finally, a case example is applied to illustrate the way in which SPNs is used for analysing and modelling construction material logistics problems.Findings – The results indicate that the impacts triggered by variations in delivery lead‐time and changes in delivery quantities can be approximated thereby facilitating decision makers to devise a more reliable and optimal materials management plan for construction projects.Research limitations/implications – The complex routing p...

Towards optimising construction-method selection strategies using genetic algorithms

Abstract Although there is a proliferation of techniques for resource-allocation problems in construction, ranging from mathematical programming to knowledge-based expert systems, there still exists a need for the use of more efficient approaches in practice. This paper presents a research study that investigates the application of genetic algorithms (GAs) to the multidimensional problem. The objective is to investigate the use of GAs for both a numerical function optimisation and a combinatorial search problem within the framework of a decision-support system (DSS). A hybrid GA system was designed for construction-resource selection, and a genetic model that represents the problem and solution space was built into the system. A genetic state-space search (GSSS) technique for multimodal functions was used to evaluate the cost profiles that resulted from different combinations of tasks and resources. The study indicates that GA systems have huge potential applications as DSS component(s) in construction-resource assignment. The results also highlighted that GAs exhibit the chaotic characteristics that are often observed in other complex non-linear dynamic systems. The paper discusses the genetic model for the problem, and the empirical results obtained. Recommendations are given on how to achieve improved results in adapting GAs for construction-resource optimisation problems.