A Model to Assess and control the Impact of Variation Orders on Time and Cost in Building Projects in Khartoum State

Abstract

Variation orders (VOs) are one of the main challenges that face all building projects stakeholders. From some preliminary investigation conducted with some construction managers in Sudan, VOs were viewed as the main cause of increase in contract value by more than 25%, extension of time and decrease in quality and productivity on building projects in Khartoum state. This research sought to identify and rank the key factors that cause VOs gauging their impact on the time, cost and overall performance of building projects in Khartoum State – Sudan .It also focused on valuing how adjustment and control of VOs could be achieved. Moreover the research aimed at developing a model to allow users to assess and later control the impact of VOs on the project time and cost performance. The research was conducted in three main stages: (case studies questionnaire surveys and a model development). 10 projects were studied thoroughly collecting information to determine the effect of VOs and this was then complemented by an industry survey, where 130 participants took part in a stratified sample comprising (47) consultants, (53) contractors, (23) projects owner and (7) experienced project managers. The data was analyzed calculating, frequency of occurrence, relative importance index, correlation coefficient (R2) and Spearman coefficient. It was evident that a substantial majority (70%) of the recorded causes for VOs were related to (client‟s changing needs, client‟s changing scope of work, design changes, instability of prices of material in local Market, Changing government regulations and legislation and Change the use of the project) .The results also confirmed a direct relationship between the presence of VOs and project‟s time overrun. It was also recorded that project‟s durations increased by (22-200) % due to VO. Cost analysis, on the other hand showed an increase by (2.67-42.86) % due to VOs.