An assessment of the causes, cost effects and solutions to design-errorinduced variations on selected building projects in Nigeria

Abstract

Design errors and variations are inherently part of many construction projects and require deliberate effort to combat. The literature reviewed indicates that empirical studies of the cost effect of design-error-induced variations are scarce. This study investigates the causes of variation on building projects, the frequent design errors that lead to variation, the effects of design error on variation cost, and solutions to design-error-induced variation in design documents. A mixed methods research (interviews and 30 case study building projects) was used to collect the necessary data for the study. Interviews were conducted with 25 construction professionals to obtain information on the causes of variation on building projects and solutions to design-error-induced variation on building construction projects. Thirty documents including valuation breakdowns and variation/change order documents were obtained by convenience sampling technique and used for the extraction of design errors leading to variations and their associated costs. The data was analysed with frequencies and percentages. The study found that poor working drawing and lack of coordination among design documents are the major causes of variation. Errors in design calculations and wrong descriptions in specifications are prominent design errors that led to variation. Design errors account for roughly 36% of the variation cost of building projects. Structural and architectural drawings contain the largest number of errors among design documents, but electrical and mechanical documents have Oluwaseun Dosumu 41the highest contribution to variation cost. The study concluded that variation costs could be minimized if government policies, aimed at ensuring proper contract documentation, were put in place, and construction professionals were limited to their core roles on construction projects. Rechecking of design documents prior to use, knowledge sharing, and use of computer programs were among the recommended solutions to design-error-induced variation in project documents.Keywords: Construction projects, cost of error, design documents, design error, variation cost, valuation documents AbstrakOntwerpfoute en -variasies vorm inherent deel van baie konstruksieprojekte wat doelbewuste pogings verg om te bestry. Die literatuuroorsig dui daarop dat empiriese studies van die koste-effek van ontwerpfout-geïnduseerde variasie skaars is. Daarom ondersoek hierdie studie die oorsake van ontwerpfoutgeïnduseerde variasie, hul effekte op variasiekoste en oplossings vir ontwerpfoute in ontwerpdokumente. Die studie is uitgevoer op geselekteerde bouprojekte in Nigerië. Die gemengde metode van onderhoud-en 30 gevallestudie-bouprojekte is aangeneem in die versameling van die nodige data vir die studie. Onderhoud is met 25 konstruksiekenners gevoer om inligting te verkry oor die oorsake van variasie en oplossings om foute van boukonstruksieprojekte te ontwerp. Dertig dokumente wat insluit waardasieafbreekpunte en variasie-/veranderingsopdragdokumente is verkry d...

Key Causes of Variation Orders in Public Construction Projects in South-South Zone of Nigeria: An Explanatory Factor Analysis

“…Sufficient time given to the designers and thorough reviewing of design details would assist in minimizing this problem. This result of the study was in agreement with previous study by Dosumu & Aigbavboa (2018) who found poor working drawing as the major cause of variation on selected building projects in Nigeria. "Inadequate project objectives" is also among the highly significant causes of variation orders as perceived by all respondents with the view that it may further add more complication to the realization of project objectives.…”

Causes of Design Change Depending on Power Project-Types in Ghana

“…This is due to the clarity of project plans, as well as the confidence of assumptions and design variables established early in the planning stage, which becomes increasingly apparent to the design team during construction [20]. Construction design changes have a huge effect on project performance; they are complex to tackle when the exact cause is unknown, although they can be managed, if not entirely reversed [21]. Alaryan et al [10] investigated the causes and effects of design change in construction projects in Kuwait and identified 20 unique items.…”

A Forecast and Mitigation Model of Construction Performance by Assessing Detailed Engineering Maturity at Key Milestones for Offshore EPC Mega-Projects

“…There are many existing publications dedicated to causes of profit losses and construction delays on international EPC mega projects: Asia [5][6][7][8][9][10][11][12][13][14][15][16], Europe [17,18], Africa [19][20][21][22], Americas [23][24][25], and Australia [26,27]. Among the factors identified, the most common cause of project schedule and cost overrun was found to be poor design development prior to construction [5][6][7][8]12,13,[15][16][17][18][22][23][24]27].…”

“…Sambasivan [6], Wong [27] and Habibi [23] hypothesized that design error and change is one of the major causes of delays through diverse data analysis techniques, such as a relative importance index ranking method, severe index, etc. Dosumu [22] indicated that about 36% of cost variation is caused by design errors, and recommended design maturity review prior to use to minimize design-error-induced variations. Many previous studies show data collection and analysis using a considerable amount of historical data.…”