An Investigation Into Design Errors And It Impact On Initial Cost Of A Construction Project

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 the 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.

 TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE STUDY

• PROBLEM STATEMENT
• OBJECTIVES OF THE STUDY
• RESEARCH QUESTIONS
• HYPOTHESIS FORMULATION
• SIGNIFICANCE OF THE STUDY
• SCOPE OF STUDY
• LIMITATION OF THE STUDY
• DEFINITION OF TERMS
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

• REVIEW OF THE STUDY
• REVIEW OF DESIGN ERROR COSTS

CHAPTER THREE

RESEARCH METHODOLOGY

• SAMPLING METHOD AND SIZE
• DATA COLLECTION
• DATA ANALYSIS AND INTERPRETATION OF FINDINGS

CHAPTER FOUR

FINDINGS/RESULTS AND DISCUSSION

• FINDINGS
• DISCUSSION OF FINDINGS

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION
• REFERENCES

 CHAPTER ONE

1.0                                                                INTRODUCTION

Construction is, by nature, complex and uncertain. Unlike the manufacturing and other sectors of the economy, the design and production activities of construction projects are usually separate functions. That is, the design and construction of a building are two separate functions performed by different parties working independently (Juliana, Ramirez & Larkin, 2005). However, these parties (contractors and consultants) have different interests in building projects. For instance, while the client wants value for money, the contractor wants to maximize profit. These interests normally lead to design error as a major source of variation, as claimed by Asamaoh & Offei-Nyako (2013).

Error is any deviation from an agreed, well-defined scope and schedule of construction projects after issuance of construction order (Osman, Omran & Foo, 2009: 142; Alaryan, Emadelbeltagi, Elshahat & Dawood, 2014: 1). Furthermore, while Love, Edwards and Irani (2008: 234) defined errors as unintended deviations from correct and acceptable practice that are avoidable, Dosumu & Adenuga (2013: 677) noted that error entails different meanings and usages depending on how it is conceptualized across different fields of study. With these assertions, design error may be defined as preventable error from acceptable standards of practice during the design of construction projects.

Many projects in developing countries suffer from slipped milestone, cost and time overrun, due to error in construction projects (Ubani, Nwachukwu & Nwokonkwo, 2010: 141). Muhammad, Keyvanfar, Abd-Majid, Shafaghat, Magana & Dankaka (2015: 91) revealed that variation occurs in all types of projects. Muhammad et al. (2015: 96) noted three prominent sources of variation: design error and omission account for 65% of variation; design changes account for 30% of variation, and other reasons account for only 5% of variation. To buttress this position, Diekmann and Nelson (1995) affirmed that variation has a 65% likelihood of being caused by design error. Therefore, it can be argued that there is a strong connection between design error and variation. It is on this basis that this study investigates the causes of variation, frequent design errors that lead to variation, cost effects of design errors on variation, and solutions to design-error-induced variation in building projects.

Researchers, including Love & Josephson, 2004; Mohammed, 2007; Long, 2011; Love, Edwards, Han & Goh, 2011; Dosumu & Adenuga, 2013; Dosumu, Idoro & Onukwube, 2017, have worked on the causes, effects and remedies of error in construction documents. Studies have also been conducted on variation and variation orders (Anees, Mohamed & Razek, 2013; Desai, Pitroda & Bhavsar, 2015). Other studies (Al-Dubaisi, 2000; Aljishi & Almarzouq, 2008; Zawawi, Azman & Kamar, 2010) were conducted to affirm that design error is the major source of variation on construction projects. However, there is a paucity of studies investigating the extent to which design errors affect variation cost of construction projects. Without identifying the

1.1                                               BACKGROUND OF THE STUDY

When asked to define “design error,” not all disciplines in the construction process agree on a common definition. Depending on which discipline you address, the owner, the designer or the contractor there will be a common understanding surrounded by varied conclusions, “a mistake.” From the basic definitions of “design” and “error” we conclude that a design error is a deviation from a drawing or specification, also including omissions and ambiguities. It is the seriousness of this error that must be considered to determine its consequences on the overall outcome of the project One of the most important challenges facing management today is controlling the all too frequent cost and schedule overruns that effect the construction industry (Diekmann and Thrush, 1986). One of the major issues to control growth in project costs and time is the reduction of design errors.

The owner, designer and contractor all have different interests in, or uses for the design of a facility. But what they do share is the commitment to complete the project safely and within a given budget and completion time. There are many initiatives being conducted to control the growth of cost and schedule within the construction industry.
The major issue is “accuracy of the drawings,” or the number of design errors, omissions and ambiguities within the plans and specifications that affect the quality of the facility. Inadequacies in the plans and specifications are the major causes of changes to the contract So much emphasis is placed on the issue of time and cost that quality takes a back seat The quality of the project depends on the conformance of the objectives and requirements from the owner. An informative quality management technique will provide an agreement to procedures and definitions among the principle parties for the project. Since design errors have an impact on the outcome of the effectiveness of the contractor’s effort on the project it is essential that all parties determine what the definition of a design error should be. When asked to define design error, not all disciplines in the construction process agree on a common definition. From the basic definition of design and error it can be determined that a design error is a deviation from a drawing or specification. It is the seriousness of this error that must be considered to determine its consequences on the overall outcome of the project

1.2                            PROBLEM STATEMENT

Design errors indicate the total design in-effectiveness of a project. Major design quality problems occur during construction when errors, omissions and ambiguities in plans and specifications become evident (Davis and Ledbetter, 1987). This statement directs that the inadequacies in the plans and specifications are the major causes of changes to the contract. There have been extreme examples of design errors such as numerous building collapse in Nigeria – projects that have wrought disaster after the construction are completed. These are examples of design errors that escaped the close scrutiny of all parties. One or two major errors that can be corrected with only cost considerations and little effect on the schedule can impact projects. The projects that really suffer are those with many small errors (design, rework or change of scope) which when finally added up cause major impacts on the cost and schedule growth. Through Davis and Ledbetters research it was determined that “accuracy of the design documents” was the most critical of the criteria used in the initial evaluation of design effectiveness. This accuracy was further described as the concern for the frequency and impact of errors in the specifications and drawings. This is due to the fact that the drawings and specifications are the most “readily identifiable outputs of the design process.” It is evermore important that the quality control of designs be addressed during the planning phase and closely monitored during the construction phase.

1.3                                             OBJECTIVES OF THE STUDY

The main aim of the study is to investigate how design errors can affect the initial cost of a project. The specific objectives are:

• To determine what constitutes a design error.
• To examine the contributing factors to design errors in Nigeria.
• To examine how these factors can affect initial cost and growth of a project.

1.4                                                      RESEARCH QUESTIONS

• What makes or contributes to a design error?
• What are the factors that lead to design errors?
• What effect can design errors have on initial cost and growth of a project?

1.5                                   HYPOTHESIS FORMULATION

Hi: There is no significant relationship between design error and initial project cost.
Ho: There is significant relationship between design error and initial project cost.

1.6                                   SIGNIFICANCE OF THE STUDY

This study gives a clear insight into the various ways in which contractors in the construction companies in Nigeria can maximise profits and reduce initial cost through effective and efficient contract planning and management. The study also gives a clear insight into the various effects of design errors on the cost of a project. The findings and recommendations of the researcher will help in building a strong and better project management guideline for contractors in Nigeria.

1.7                                         SCOPE OF STUDY

This research focuses mainly on the investigation of design errors on initial cost of a project. Results and recommendations may not be used to generalise other construction companies in Nigeria, as the researcher could not cover a wider scope due to financial and time constraints.

Based on the findings of this study other possible researchable areas may include studies on the various effects of other aspects of contracts such as contract laws in Nigeria and contract management and control.

1.8                             LIMITATION OF THE STUDY

The only limitation faced by the researcher in the course of carrying out this study was the delay in getting data from the various respondents. Most respondents were reluctant in filling questionnaires administered to them due to their busy schedules and nature of their work. The researcher found it difficult to collect responses from the various respondents, and this almost hampered the success of this study.

1.9                                 DEFINITION OF TERMS

• Design: The basic definition of design, according to Webster, is “the making of drawings or plans to plan and fashion the form and structure of an object to have intentions or purposes.” The quality of planning and design is one of the primary factors of success in any project endeavor (Chalabi, Beaudin and Salazar, 1987). The design includes every aspect of the facility construction including operation and maintenance. The design incorporates a set of specifications to guide the contractor in developing his means and methods of construction. Figure 2-1 shows the traditional flow diagram of a design/construction method.
• Error: An error is defined, according to Webster, as “a deviation from accuracy or correctness; a mistake, as in action or procedure; an inaccuracy, as in speaking or writing.” There are basically three types of errors: imperfections, non-conformance and omissions. Imperfections are deviations in details that have no affect on the assembly or facility (Davis and Ledbetter, 1987).
• Design Error: From the evaluation above a simple definition of design error is “a deviation from the plans and specifications.” It is not the intention of this definition to include any cost or schedule growth or insinuate its root causes or legal responsibility. It is the responsibility of the owner, designer and contractor to establish the criteria in order to make a reasonable determination for responsibility. The survey shows a common theme, that of a mistake or error in the design. The survey also indicates several reasons why design errors exist and who cause them. This provides evidence that there is not a concise definition within the construction industry.
• Contract:  Erikson (2002) defined Contract as an agreement that creates an obligation binding upon the parties thereto. The essentials of a contract are as follows: (1) mutual assent; (2) a legal consideration, which in most instances need not be pecuniary; (3) parties who have legal capacity to make a contract; (4) absence of fraud or duress; and (5) a subject matter that is not illegal or against public policy.
• Contract Planning: According to Simmons (2007), Contract planning is the process of systematically and efficiently managing contract creation, execution and analysis for maximizing operational and financial performance and minimizing risk.
• Contractor: General contractor, organization or individual that contracts with another organization or individual (the owner) for the construction of a building, road or other facility.
• Profit:  Tucy (2008) defined profit as the difference between the purchase price and the costs of bringing to market
• Initial Cost: Initial costs are fixed, one-time expenses incurred on the purchase of land, buildings, construction, and equipment used in the production of goods or in the rendering of services. Put simply, it is the total cost needed to bring a project to a commercially operable status. Whether a particular cost is capital or not depend on many factors such as accounting, tax laws, and materiality.

1.10                                                      PROJECT ORGANIZATION

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied,  chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.