A post-contract project analysis of material waste and cost overrun on construction sites in Abuja, Nigeria

Material waste and cost overrun have been identified as common problems in the construction industry. These problems occur at both pre- and post-contract stages of a construction project. As a result of a dearth of empirical research and low level of awareness, the majority of managers of construction projects in Nigeria pay hardly any attention to material waste issues that affect cost overrun. This article examines the material waste issues that affect cost overruns at the post-contract stage of building projects. The study covers building construction projects in Abuja, Nigeria. In-depth interviews were conducted with professionals using purposive sampling technique. It is purposive, because only building professionals handling projects that are worth over eight million USD are consulted/interviewed. The professionals included 15 project managers, nine quantity surveyors, five site engineers and one senior technical officer of a waste management department/unit. The interviews were on issues relating to material waste and cost overruns at the post-contract stage of a project. The collected data were analysed manually, using the deductive approach. This involves constant comparative analysis of the data to generate common patterns on material waste and cost overrun. The research found that poor quality-of-procurement management, construction management, and site management would cause material waste, which contributes to project cost overruns. A good-quality procurement management entails procuring the appropriate materials, at the right time and in accordance with specifications. Rework, site accidents, inadequate site security/fencing, poor site organisation and discipline, construction-site disputes, lack of experience, and lack of co-ordination among the parties all contribute to material waste and cost overruns. It can be concluded that proper attention to material waste issues has the potential to minimise the rate of cost overrun at the post-contract stage of a project. It is recommended that careful attention should be paid to the issues identified in this study, as they would help reduce the rate of material waste and cost overrun for projects

The contributions of construction material waste to project cost overruns in Abuja, Nigeria

Material wastage on construction sites can contribute to cost overruns. Research to provide evidence of the extent of material wastages’ contribution to cost overruns on construction sites is based mostly on surveys. Thus, the actual contribution is not yet ascertained. The purpose of this article is to report the results of an objectively investigated study on the contributions of material waste to project-cost overrun. The methodological approach adopted for the study is the quantitative technique that is rooted in the positivist paradigm. The investigation included ongoing building construction projects within Abuja, Nigeria, from which a sample of 31 public and private projects was purposefully selected (project value of ?1.6 billion Naira and above). The data for this research were sourced from the field investigation (measurement of the volume of material waste) and data from the archival records (drawings, bills of quantities, project-progress reports, and specifications) on material waste and cost overruns. The collected data were analysed using the Pearson moment correlation and the descriptive method. The research results revealed a statistically significant relationship between material waste and cost overrun. This implies that any increase in the volume of material waste would lead to a corresponding increase in the amount of cost overrun. The results showed that the significant percentage contribution of material waste to project-cost overrun ranges from 1.96% to 8.01%, with an average contribution of 4.0% to project-cost overruns. It is recommended that construction professionals be well informed of the consequences of material waste contributions to project-cost overrun at an early stage, in order to enable the professionals to evaluate the extent to which these consequences could be minimised

An investigation into cost overruns for ongoing building projects in Abuja, Nigeria

The total amount of cost overruns for any construction project can be fully determined once the project is completed. Estimating the amount of cost overruns at different stages of ongoing construction projects is important for project success. There is, however, a dearth of research for this exercise. This article reports the results of an investigative study on cost overruns for ongoing building projects in Abuja. The quantitative technique was adopted in this study. The investigation included ongoing building-construction projects within Abuja, from which a sample of 30 building projects (public and private) was purposively selected (project value of ZAR100 million and above). The data were sourced from the archival records (drawings, bills of quantities, project progress reports, and specifications) on the issues relating to the costs and duration of building projects. The data were analysed using descriptive (percentages) and inferential methods. The results revealed that the percentage of cost overruns ranged from a minimum of 5.56% with 90% project completion, and within 88% of the estimated time limit, to a maximum of 216.08% with merely 5% project completion, and within 8.3% of the estimated time limit. The entire projects had average cost overruns of 44.46%, with an average project completion of 52.4%, and within 91.4% of the average estimated time limit. Based on these findings, it can be concluded that continuous investigation into, and analyses of cost overruns at stages of building projects would encourage professionals to apply the best mitigation measures, in order to achieve a significant reduction in the total cost overrun at the completion of a project. Construction professionals should be well informed of these consequences (cost overruns) at an early stage, in order to evaluate the extent to which these consequences could be minimised

Management of material waste and cost overrun in the Nigerian construction industry

While wastage of materials has become a serious problem requiring urgent attention in the Nigerian Construction Industry, cost overrun is a problem, which affects 90 percent of the completed projects in the world; the argument on how to reduce/eliminate cost overrun has been on-going for the past 70 years; as the on-site wastage of materials leads to increases in the final project cost. Studies from different parts of the world have shown that construction-material waste represents a relatively large percentage of the production costs. Consequently, as a result of low levels of awareness, the Nigerian construction industry pays little attention to the effects of generated material waste on cost overruns. Thus, this research aimed to investigate the relationship between material waste and cost overrun in the Nigerian construction industry. A comprehensive review of the related literature revealed that all material waste causes are related to cost overrun causes at both pre-contract and post-contract stages of a project; but not vice versa. The mixed method (quantitative and qualitative) approach that is rooted in the positivist paradigm was adopted for this study. Abuja, the federal capital territory of Nigeria was the selected geographical scope of this research, out of which thirty-one (31) construction projects were purposeful selected (projects to the value of 100 million Rand/1.6 billion Naira and above).The research instrument was an interview guide used in conjunction with a tick box. Other sources of data included field investigation (measurement of onsite material waste) and the collection of archival records from bills of quantities, project records, and specifications. Analyses of the findings lead to the conclusion that a relationship exists between material waste and cost overrun; at the pre-contract and at the post-contract stages of a project. The implication is that an increase in material wastage on-site leads to a corresponding increase in the amount of cost overrun, regardless of the percentage allowance for material waste in the process of bill preparation. The study also concluded that the average percentage contribution of material waste to project-cost overruns is four (4) percent. Material-waste sources, causes, and control measures were found to have significant effects (very high, high, medium, low, and very low), in causing or minimising cost overruns at both pre-contract and post-contract stages of projects. The research has developed a conceptual model for the management of material waste and cost overruns in the construction industry based on the results and informed by the theoretical framework. The research has also developed a mathematical model for quantifying the amount of material waste to be generated by a project; as well as a mathematical equation for the effective management of material waste and cost overrun for projects. The study has achieved its aim of establishing an understanding of the issues leading to the relationship between material waste and cost overruns, as well as their management in the Nigerian construction industry. The study recommends that the management of material waste and cost overrun should be revised, based on the findings of this research and included as part of the procurement process. The mathematical models for quantification of onsite material waste, and the mathematical equation for managing material waste and cost overruns developed in the study, could be usefully adopted to improve management of material waste and cost overrun in the Nigerian construction industry

Utilisation of forecasting technology for improving construction logistics in Nigeria

The need to investigate new technology for forecasting purposes in construction logistics is due to the fact that the forecasting ability (modern technology utilisation) of the Nigerian construction sector, in terms of logistics management, is relatively low when compared to manufacturing and retailing industries. This is affecting the performance of the construction sector. Moreover, the current logistics technologies used for forecasting operations in the Nigerian construction industry are relatively inefficient and insufficiently investigated to inspire new logistics technologies for the construction industry. Hence, this article investigated how forecasting logistics technologies could be utilised in manufacturing and retailing industries, in order to improve the forecasting processes of construction logistics. Lagos State and Abuja, the Federal Capital Territory of Nigeria, formed the selected geographical scope of the study, from which five manufacturing; five retailing companies, and five construction projects were purposely selected. A mixed methods research strategy were used. The research instruments included an observation guide (quantitative) and semi-structured interviews (qualitative). The collected quantitative data were analysed, using descriptive analytical tools: frequencies and percentiles. The qualitative data was analysed, using the thematic method. The results revealed that all the observed manufacturing industries (100%) adopted the Enterprise Resource Planning (ERP) technology for forecasting purposes in the following areas: material, demand, product, and production forecast. Of the observed companies in the manu-facturing and retailing industries, 80% and 40%, respectively, adopted the Material Requirement Planning (MRP) technology for forecasting purposes. Only 20% (one project) of the observed construction projects adopted the MRP technology for fore-casting in the following: 5% for demand forecast (demand control); 6.7% for material forecast (stock control), and 20% for product forecast (product output). It was also revealed that utilisation of the forecasting technology in construction could have the following benefits: proper resource planning; improved production scheduling; reduction in inventory; effective treatment of scheduling problems, and efficiency of the supply-chain system. Results showed that effective tilisation of forecasting technology in the logistics system of the construction industry could lead to full efficiency gains in forecasting logistics of the construction industry. It is recommended that the Nigerian construction industry should leverage on this, in order to create the best ways of handling the forecasting technology to improve the forecasting logistics systems of the construction process

Management of material waste and cost overrun in the Nigerian construction industry

While wastage of materials has become a serious problem requiring urgent attention in the Nigerian Construction Industry, cost overrun is a problem, which affects 90 percent of the completed projects in the world; the argument on how to reduce/eliminate cost overrun has been on-going for the past 70 years; as the on-site wastage of materials leads to increases in the final project cost. Studies from different parts of the world have shown that construction-material waste represents a relatively large percentage of the production costs. Consequently, as a result of low levels of awareness, the Nigerian construction industry pays little attention to the effects of generated material waste on cost overruns. Thus, this research aimed to investigate the relationship between material waste and cost overrun in the Nigerian construction industry. A comprehensive review of the related literature revealed that all material waste causes are related to cost overrun causes at both pre-contract and post-contract stages of a project; but not vice versa. The mixed method (quantitative and qualitative) approach that is rooted in the positivist paradigm was adopted for this study. Abuja, the federal capital territory of Nigeria was the selected geographical scope of this research, out of which thirty-one (31) construction projects were purposeful selected (projects to the value of 100 million Rand/1.6 billion Naira and above).The research instrument was an interview guide used in conjunction with a tick box. Other sources of data included field investigation (measurement of onsite material waste) and the collection of archival records from bills of quantities, project records, and specifications. Analyses of the findings lead to the conclusion that a relationship exists between material waste and cost overrun; at the pre-contract and at the post-contract stages of a project. The implication is that an increase in material wastage on-site leads to a corresponding increase in the amount of cost overrun, regardless of the percentage allowance for material waste in the process of bill preparation. The study also concluded that the average percentage contribution of material waste to project-cost overruns is four (4) percent. Material-waste sources, causes, and control measures were found to have significant effects (very high, high, medium, low, and very low), in causing or minimising cost overruns at both pre-contract and post-contract stages of projects. The research has developed a conceptual model for the management of material waste and cost overruns in the construction industry based on the results and informed by the theoretical framework. The research has also developed a mathematical model for quantifying the amount of material waste to be generated by a project; as well as a mathematical equation for the effective management of material waste and cost overrun for projects. The study has achieved its aim of establishing an understanding of the issues leading to the relationship between material waste and cost overruns, as well as their management in the Nigerian construction industry. The study recommends that the management of material waste and cost overrun should be revised, based on the findings of this research and included as part of the procurement process. The mathematical models for quantification of onsite material waste, and the mathematical equation for managing material waste and cost overruns developed in the study, could be usefully adopted to improve management of material waste and cost overrun in the Nigerian construction industry

Utilisation of order processing technology for logistics process improvement in the Nigerian construction industry

The logistic technologies for effective and efficient ‘order processing operations’ in the areas of tracking, shipping, replenishment, dispatching and holding of inventory are deficient in the Nigerian construction industry, when compared to manufacturing and retailing sectors. This is confirmed to have a significant effect on the performance of the construction sector. This article assessed how order processing technology utilised by manufacturing and retail industries could improve the order processing logistics operations of the construction industry. Lagos State and the F.C.T. Abuja, Nigeria, were the selected geographical study areas, from which five manufacturing companies, five retailing companies and five construction projects were purposively selected. Mixed methods research strategy was used. The research instruments included an observation guide (quantitative) and semi-structured interviews (qualitative). The collected quantitative data was analysed, using descriptive analytical tools: frequencies and percentiles. The qualitative data was analysed, using the thematic method. The result revealed that 80% and 100% of the manufacturing and retailing industries, respectively, observed, adopted barcoding technology for order processing purposes. Only 40% of the observed construction project adopted barcoding technology for order processing in the following: 2.4% for receiving process; 0.9% for put-away process; 0.9% for shipping process (stock control); 1.2% for dispatching process; 0.6% for replenishment process, and 1.2% for tracking inventory (stock tracking). In addition, 100% and 80% of the manufacturing and retailing industries, respectively, observed, adopted Radio Frequency Identification (RFID) technology for order processing purposes. Only 40% of the observed construction projects adopted RFID technology for order processing. It was also revealed that utilisation of the order processing technology could have the following benefits: managerial control in the construction industry; shorter processing time; easy way of tracking materials on site, and increased speed of work in the construction industries. The research concludes that effective utilisation of order processing technology in the logistics system could lead to full efficiency gains in the order processing aspect of the construction industry. It is recommended that the Federal Government of Nigeria should mandate all major construction project stakeholders to attend workshops on the use of recent technologies in the management of construction operations

The effect of poor materials management in the construction industry: A case study of Abuja, Nigeria

Effective materials management on construction sites is handled carelessly by construction practitioners. This may result in several challenges such as materials waste generation, poor quality of work, project delays, and poor materials flow. Construction practitioners in Abuja, Nigeria, do not understand the consequences of these challenges to construction projects. This article investigates the effect of poor materials management on materials waste, quality of work, and project profitability in construction projects in Nigeria. A qualitative research approach was adopted in the study which included collective case study investigations. The population for the study was ongoing building project sites (ten case studies purposefully selected) in Abuja. The research instrument was direct-covert observation by the researchers to observe and record the construction processes, people’s behaviour, actions and interactions relating to materials management. The construction processes observed included materials usage onsite, loading/offloading of materials from procurement, storages, as well as materials handling and movement on site. Recording sheets with checklists were pre-set with statements (Likert items) and responses to observe and document the effect of poor materials management. The statements were rated on an ordinal three-point Likert scale. The observed/collected data were analysed using descriptive methods to determine the modal values. The findings from the study revealed that poor materials management has a considerable effect on material waste generation on any construction project site; moderate effects on quality of building projects, and both considerable and moderate effects on profitability in the construction projects. Based on these findings, it can be concluded that effective management of materials in construction projects would reduce the amount of waste generation, increase the quality of construction work, and offer optimum profitability to construction contractors. It is, therefore, recommended that the construction industry in Nigeria should collaborate with government agencies to develop guidelines for preparing a waste management plan for the construction industry

Hyper-Erlang Battery-Life Energy Scheme in IEEE 802.16e Networks

IEEE 802.16e networks is one of the broadband wireless technologies that support multimedia services while users are in mobility. Although these users use devices that have limited battery capacity, several energy schemes were proposed to improve the battery-life. However, these schemes inappropriately capture the traffic characteristics, which lead to waste of energy and high response delay. In this paper, a Hyper-Erlang Battery-Life Energy Scheme (HBLES) is proposed to enhance energy efficiency and reduce the delay. The scheme analytically modifies idle threshold, initial sleep window and final sleep window based on the remaining battery power and the traffic pattern. It also employs a Hyper-Erlang distribution to determine the real traffic characteristics. Several simulations are carried out to evaluate the performance of the HBLES scheme and the compared scheme.  The results show that the HBLES scheme out performs the existing scheme in terms of energy consumption and response delay

Public key exponent attacks on multi-prime power modulus using continued fraction expansion method

This paper proposes three public key exponent attacks of breaking the security of the prime power modulus =22 where and are distinct prime numbers of the same bit size. The first approach shows that the RSA prime power modulus =22 for q<<2q using key equation −()=1 where ()= 22(−1)(−1) can be broken by recovering the secret keys  / from the convergents of the continued fraction expansion of e/−23/4 +1/2 . The paper also reports the second and third approaches of factoring multi-prime power moduli =2 2 simultaneously through exploiting generalized system of equations −()=1 and −()=1 respectively. This can be achieved in polynomial time through utilizing Lenstra Lenstra Lovasz (LLL) algorithm and simultaneous Diophantine approximations method for =1,2,…,