Positive and Negative Implications of Design Variation on Construction Projects Delivery in Niger-Delta Region of Nigeria

Positive and Negative Implications of Design Variation on Construction Projects Delivery in Niger-Delta Region of Nigeria

Lashinde, Adeniran, Samuel Ekung

Department of Quantity Surveying University of Uyo, Akwa Ibom State Nigeria

DOI: https://dx.doi.org/10.47772/IJRISS.2025.9010198

Received: 21 December 2024; Revised: 02 January 2025; Accepted: 07 January 2025; Published: 12 February 2025

ABSTRACT

The study investigated on the implications of design variation on the construction projects delivery in Niger-Delta region of Nigeria. The study focuses on the positive and negative impacts of design variations on project delivery and the strategies   to minimizing occurrence of design variations on construction projects. It was an exploratory research employing questionnaire survey administered to the construction project stakeholders in the study area. A total of 345 copies of questionnaire were administered and 195 was retrieved and used for the analysis. Data collected were analyzed with mean score, relative important index and standard deviation. The study revealed that the most significant positive implications of design variation are cost reduction,time reduction and client’s satisfaction. The study further revealed that the most important negative implications of variations are cost overrun, time overrun and meeting quality standard. The mitigation measure are availability of detail   soil investigation and complete drawings prior the bidding, Use up-to-date technology utilization and improving contract award procedure by giving less weight to prices and more weight to the capabilities and past performance of contractors. The study concluded that design variations can only be entertain or accepted if it is not detriment to the clients and have positive impacts on the construction projects output. The study recommended that the provision of clause for variation order in construction is overdue and needs to be reviewed

Keywords: Implications; Design Variation; Construction; Projects Delivery; Niger-Delta; Nigeria

INTRODUCTION

The construction industry plays a significant role in infrastructure and economic development of any nation. It is the prime mover of a nation that provides the driving force for sustaining nation’s economy. It accounts for a large share of gross domestic product and employs larger percentage of people compare with other sectors in both developed and developing countries. Construction industry of any country is the backbone of her infrastructure and economy development, anything that affects the industry has a multiplier effect on the level of infrastructure and economic development of the country (Lashinde, 2016). The Nigerian construction sector plays a vital role in the national economy as it contributed ₦12.9 trillion to the Gross Domestic Product (GDP) in the second quarters of 2022. It contributed 3.21% to GDP higher than its contribution of 3.19% in 2021. The aggregate GDP stood at N45 million in 2022. This performance is higher than N39.1 million in 2021 second quarter. (National Bureau of Statistics NBS, 2022).The industry also contributes 2.3% to the employment rate in the country which is equivalent to 1.8 million in 2019. This employment level places construction industry among top 10 sectors in terms of employment stock (National Bureau of Statistics NBS, 2019).  The huge size of construction industry indicates that its efficiency paramount and vital to the overall performance of the nation’s economy. Therefore, the design team should work hand in hand to reduce wasteful practices to the lowest minimum if not totally eradicated. The complexity, uniqueness and fragmentation nature of the construction industry due to different stakeholders’ involvement, multiple tasks, mixes skill and work environment makes it differ from other industries. These leads to unwanted situations like variations with their associated impacts on the project delivery. These impacts could be positive or negative to the clients, nation’s economy and physical environmental development.

Construction projects involve a lot of interrelated activities in which some may not be totally foreseen until the actual construction is taking place at the various sites due to the difference in soil strata and environmental condition. Although this can be reduced to the minimum or overcome if thorough cost planning and control and soil investigation were carried out at the pre-contract stage.  Porkharel and Joshi (2020) defined construction contract as a business agreement that is subjected to variability, and that variation orders consist of the additions, omissions, alterations and substitution in terms of quality, quantity and schedule of works. In construction projects, there are contractual clauses relating to changes allow parties involved in the contract to initiate variation without any objection and the contractor confirm the  order(s) from the prime consultant in written within 7 days of such notice. Although it’s not in all cases that clauses relating to variation is included in construction contract. Some contracts are on fixed price sum contract where variation and fluctuation are not inclusive. designingbuildings.co.uk (2023 ) postulated that design Variations might include:Alterations to the design; Alterations to the quantities require; Alterations to the quality required; Alterations to working conditions and; Alterations to the sequence of work. further stated that design Variations  may also be deemed to occur if the contract documents do not properly describe the works actually required.

In accordant with the Joint Contract Tribunal standard form of contract (JCT, 2016) design variation in construction refers to a change in the works initiated by the engineers, consultants, employer or other factors as the case may be which involves the alteration of any kind or standard of materials to be used in the work. Variation orders encompass modifications introduced to the original contractual agreement made among the parties involved in the construction project (Suleiman and Luvara 2016 )

Design variation cut across all construction projects both building and civil engineering projects.

designingbuildings.co.uk (2023) stated that civil engineering projects variations can be very significantly, whereas on small building contracts may be relatively minor. Variations in road construction works can result in a substantial alteration of the contract terms, quality of the construction projects, project duration and project cost execution (Albhaisi 2016; and Oyewobi et al, 2016). Variations in road construction production predominantly emanate from clients, consultants, and contractors (Suleiman and Luvara, 2016). In terms of negative impact of variation on projects and projects environment. The design variation Detriment, destructive and unpleasant and its implications goes beyond cost and completion date of the projects, it could lead to project abandonment and even bankruptcy of the client as well as economy and physical development level of the location of the projects if numerous abandoned or uncompleted projects liter the environment. This could also prone insecurity in the environment where abandoned projects can be used to perpetrate evils by the kidnappers, hoodlums and men of underworld.

Globally, design variation in construction projects cut across all construction projects at various stages of construction activities. The implications of variation either positive or negative has multiplier effects on economy and physical development as well as environmental security. Although the benefit of variation order should be to realize a balance between cost, function and quality required of a project to the satisfaction of clients in order to increase the value of the construction projects. The variation clause is allowing an employer to pursuit the aesthetic consideration in one project. (Lawteacher.net, 2024). In terms of the reasons for the justification of design variation orders, designingbuildings.co.uk (2023) affirmed that the reasons for variations include: Technological advancement; Changes in the client’s requirements; Statutory changes; Change in conditions; Geological anomalies; Non-availability of specified materials and; Development of the design after the contract has been awarded.

Numerous previous research studies have been carried out on design variation: the causes of variation in construction project ( Adu et al., 2020; Choudhry et al., 2017; Mohammed 2017 ; Ekhator 2016 and ; Yadeta,  2016); Factors Affecting Design Changes in Construction Project (Suleiman and Luvara 2016 ); Impact of variation on construction cost (Porkharel and Joshi, 2020; Aslam et al. 2019; Oyewobi et al, 2016 ) Approaches on Mitigating Variation ( Gatitu et al., 2020). However, the implications of design variation on construction projects delivery and environmental development is paramount due to the multiplier effect on the projects, the clients, the project participants as well as the environmental development in which the projects is located.  Also base on the fact that no research has been done in this aspect. Therefore it is on these background that investigation on the implications of design variation on construction projects delivery and environmental development in Niger-Delta region Nigeria was carried out.

BRIEF OF LITERATURE REVIEW

Globally, variation occurs in construction works at various stages and its implications are either positive or negative to the clients and nations’ economic development. Finsen (2012) affirmed that despite there has been significant improvement in the management of construction activities, yet the problem of cost variation remains a problem yet unsolved. Variation could be classified as beneficial or detrimental to the clients.

When a variation seeks to optimize the client’s benefits by eliminating unwarranted costs is referred to as beneficial, which means it has positive impact to the clients and nations’ economic and physical development. While it is referred to as detrimental when it has negative impact to the clients and nations’ economic and physical development. Further, variation order could only be emanated from the client and consultants as in conventional (traditional) procurement system or emanated from clients, promoters and consultants as in non-conventional procurement system such as Design and Build, BOT, BOOT, PPI and PPP.

In the conventional procurement system, if the client brief is not detail enough during design stage and change the concept when the construction is ongoing. The consultants effect the changes and compelled the contractor to implement the new concept. On the other hand, the consultants can also issue variation order to the contractor to cover their omissions or alterations which, were not considered during the design stage as in detail drawing or preparation of bidding documents and compelled the contractor to implement the changes as additional work that attracts additional cost which can be derived from the contingency sum if the cost is not more than the sum. In case the cost is more than contingency sum, it become additional cost to the client.

The occurrence of design variation is at the construction stage due to some unforeseen circumstances that were not detailing at the design stage or changes in the client’s requirements. The design variation could be initiated by the clients or consultants due to some circumstances that will add value to the projects. Porkharel and Joshi (2020) postulated that one of the major problems faced by construction project is the issue of variation orders occurring during the construction phase which results in delaying projects, overruns the cost and causes other negative effects.

METHODOLOGY 

The study adopts the exploratory survey design approach that involves structured multiple-choice questionnaire in achieving the objectives of the study on the assessment of design variations in construction projects in Niger-Delta region. The target population of the study comprises clients, registered contractors and the professionals involved in the public project delivery in the region. The sample frame of 975 was obtained from the lists of registered contractors with the corporate organisations, federal and state establishments in the respective states that form Niger-Delta region. While that of the consultants were gotten from the lists obtained from the various professional bodies at their respective state chapters. Sample of 345 obtained from the population that comprises 75 clients, 105 contractors, 45 architects, 45 engineers, 40 quantity surveyors and 35 builders. Combinations of simple random and stratified sampling techniques were adopted for the study. The questionnaire had multiple choice scaled questions and consists of two sections. Section ‘A’ dealt with the demographic characteristics of the respondents while section ‘B’ contains information on the implication of variation on construction projects delivery. The questions in this section are scores on a 5-point liker scale rating ranging from1-5: 1= not significant, 2= less significant, 3= significant, 4= very significant and 5= extremely significant in order to analyse the implications of variation(s) on construction projects delivery.

The reliability test of the research instrument was carried out by calculating Cronbach’s alpha coefficient using Statistical Package for Social Sciences (SPSS).  The Cronbach’s α value concurred that the value range from  0 to 1 and the degree of realiabilty of the instrument is more perfect as they tend towards 1. the result obtained for the different measuring scale used indecated that the Cronbach’s α value ranged from 0.725 – 0,855. The positive impacts of design variations on project delivery has 0.855 Cronbach’s α value; the negative impacts of design variations on project delivery has 0.765 Cronbach’s α value and the strategies to minimizing occurrence of design variations on construction projects has 0725 Cronbach’s α value. The Cronbach’s α value tend towards 1.0, and can be concluded that the instrument used for the research is significantly reliable.

A total of 195 questionnaire were dully completed, returned and valid were used for the analysis given a valid response rate of 56.52%. This response rate was considered as sufficient for the analysis. Data collected were processed using Statistics Package for Social Sciences (SPSS). Methods of data analysis used were Mean score and Relative Importance Index (RII).

The ranking of the variables was determined based on the Mean Score (MS) which was calculated by the following equation:

\[ MS = \sum_{i=1}^{5} \frac{RP_i R_i}{n}, \quad (1 \leq i \leq 5) \]

i=1

where MS = Mean Score,  R_P1= Rating  point I ( range from 1-5),

Ri = response to rating point, i and n = total responses = summation of Ri from 1 – 5

The decision rule is that MS ≥ 3.5 were considered as significant while variables with MS < 3.5 as insignificant based on Kazaz et. al. (2008).

Relative Importance Index (RII) was also used to determine the relative importance of the skills required for effective construction site management. The five-point scale mentioned earlier was transformed to relative index for each factor using the ranks of different factors and procedures. These ranking made it possible to cross-compare the relative importance of these skills as perceived by the respondents. The higher the value of RII indicates that the more important was the skill. Relative Importance Index (RII) for each individual factor, using the following formula, as adopted by Iyer and Jha, (2005);

Relative importance index (RII) = W ÷ (H x N) …. … …. ….. … ….. …. …..     (2)

Where W is the total weight given to each factor by the respondents, which ranges from 1 to 5 and is calculated by an addition of the various weightings given to a factor by the entire respondent, H is the highest ranking available (i.e. 5 in this case) and N is the total number of respondents that have answered the question.

Analysis and Results

Table 1 shows the positive implications of design variation(s) on construction project delivery in Niger-Delta region Nigeria in relation to cost and time. The analysis of the survey response data produced mean value for the 11 variables ranging from 3.49 to 4.65. this indicates that all the 11 variables are significant on the positive implications of design variation(s) on construction project delivery in the study area. The standard deviation (SD) of the responses, which measures the variability or dispersal of the responses and demonstrates how clustered the response values are around the mean for each of the variable. The result shows that Cost reduction was ranked 1^st with mean score and RII of 4.58 and 0.108 respectively. Time reduction and clients’ satisfaction were ranked 2^nd and 3^rd respectively with mean scores of 4.46 and 4.08 respectively. These was due to the fact that design variation is not in all cases has negative effect on the project outcome. This could be interpreted that the variation might be changing in an expensive construction component to a less expensive construction component of equal and comparative standard.  Never the less, what affect construction time almost have effect on the cost. Therefore, construction time reduction most have positive effect on cost reduction since if time elongates cost also increases. Although if there is efficient cost planning and control at the initial stage of the construction projects all the issues that could lead to variation(s) might have totally resolved.

Table 1: Positive Implication of Design Variation on Construction Projects in Niger-Delta Region of Nigeria

Table 2 shows the negative implications of design variation(s) on construction project delivery in Niger-Delta region Nigeria in relation to cost and time. The result indicated that all the 8 factors were significant due to the fact that the mean score ranges between 2.8 – 4.58. Cost overrun was ranked as the 1^st with mean score and RII of 4.58 and 0.138 respectively. Time overrun and Quality standard were ranked 2^nd and 3^rd respectively with mean scores of 4.34 and 3.90 respectively. Professional relations with mean score of 3.75 and RII of 0.117 respectively was ranked 4^th. Disputes between parties to the contract with mean score of 3.45 and RII of 0.108 respectively was ranked 5^th. Others were: Suspension of Project, Client dissatisfaction, Client bankruptcy and Abandonment of Project in that decline order.

Table 2: Negative Implication of Design Variation on Construction Projects in Niger-Delta Region of Nigeria

Table 3 shows the strategies to minimising the occurrence of design variation on construction projects delivery. The table used a five point lickert scale to determine and rank the measures to miminising variation in construction project according to its relevance and level of acceptance by construction professionals. The scale were as follows; 5= strongly agree, 4= agree, 3= somehow agree= 2= disagree, 1= strongly disagree.

The result shows that, Detailed soil investigation and complete design drawings during tendering was ranked 1^st with mean score and RII of 4.35 and 0.870 respectively. Use up-to-date technology utilization and improving contract award procedure by giving less weight to prices and more weight to the capabilities and past performance of contractors were ranked 2^nd and 3^rd with RII of 0.851 and 0.786 respectively. Other strategies are; the consultants should closely coordinate the project designing stage with RII of 0.783 ranked 4^th; identification and understanding of contract terms before the project starts ranked 5^th with RII of 0.775; while Clear information and communication channels ranked 6^th with RII of 0.755.

Table 3: Strategies to Minimising the Occurrence of Design Variation on Construction Projects in Niger-Delta Area

DISCUSSION OF FINDINGS

Based on the data acquired and analyzed, the study revealed that variation order can be caused by either client or consultants. The study further revealed that the significance determinants of variation in construction projects are Change of plans or scope by owner, change in specifications by owner and owner’s financial problems, This in line with the  Noraziah, et al.,(2017) .

The implication of design variation was classified into positive and negative based on the relevant literature. The study revealed that cost reduction , time reduction and clients’ satisfaction in that order were the most significant positive impact of design variation on construction projects in Niger-Delta region of Nigeria.  This is in line with Koushki et al., (2005 ) Studies revealed the significant reduction in both cost increase and time delay as a result of a complete design before commencement of works on site resulting in the prevention of variation orders. This shows that design variation also has positive effect on the project outcome. In term of the negative impact, the study revealed that cost overrun, time overrun and meeting Quality standard were the most significant negative impact of design variation on construction projects in Niger-Delta region. This is in line with Okafor (2020) that the performance objectives defect due to variation of many completed and ongoing construction projects. The most significant strategies to minimise design variation were availability of detailed site investigation and complete design prior to tendering, Use up-to-date technology utilization and improving contract award procedure by giving less weight to prices and more weight to the capabilities and past performance of contractors.

CONCLUSION

Based on the analysis of the data collected and the findings of the study, the following conclusions were drawn. The design variations can only be entertain or accepted if it is not detriment to the clients and have positive impacts on the construction projects. Also that detail soil investigation and detail complete drawings be available prior to bidding. The study recommended that the clause allowing clients or consultants on variation order is long overdue and need to be reviewed in a way that if variation will have positive impact on the construction project success in term of construction cost falls within the budget, completion time falls within project duration and meeting quality standard specified. Also, the result of the soil investigation must be attached to the detail drawings for bidders interested in bidding for the construction projects.

REFERENCES

1. Adu, E.T, Ekung, S.B and Lashinde, A.T (2020)Key Causes of Variation Orders in Public Construction Projects in South-South Zone of Nigeria: an Explanatory Factor Analysis. International Journal of Engineering and Science Invention. Vol. 12(1) pp.1-14
2. Albhaisi, M.A (2016) “Factors Causing Variation Orders in Construction Projects in Gaza Strip (Case Study: Qatar Projects),” M.S. thesis, The Islamic University–Gaza, Gaza, Palestine.
3.  Aslam, M., Baffoe-Twum, E and Saleem, .F.(2019) “Design Changes in Construction Projects – Causes  and Impact on the Cost,” Civil Engineering Journal, Vols. Vol. 5,, no. No. 7,, pp. 1647-1655
4. Aziz R. F. and Abdel-Hakam, A. A. (2016) Exploring delay causes of road construction projects in Egypt, Alexandria Engineering Journal, vol. 55, no. 2, pp. 1515–1539
5. Choudhry,R. M., Gabriel,H. F., Khan, M. K. and Azhar,S (2017). “Causes of Discrepancies between Design  and Construction in the Pakistan Construction Industry,” Journal of Construction in Developing   Countries, pp. 1- 18
6. Ekhator, O.J. (2016) Identifing factors Causes Variations in Private Residential Building Projects in Lagos  State. International Journal of Science, Environment and Technology,  ISSN 2278-3687 (O)  Vol.  5, No 5, 2016, 3583 – 3595
7. Finsen, E, (2012). The Building Contract – A commentary on the JBCC Agreement, 1st ed Cape Town: Juta and Co; Ltd
8. Gatitu, J.N., Kabubo, C.K. and Ajwang P (2020) Approaches on Mitigating Variation Orders in Road Construction Industry in Kenya: The Case of Kenya National Highways Authority (KeNHA).  International journal of Engineering, Technology & Applied Science Research Vol. 10, No. 5, 2020,      6195-6199
9. Joint Contracts Tribunal, (2016) Standard form of building contract. Joint Contract Tribunal Limited
10. Lashinde, A.T (2016) Framework for Attracting Investors to Public Private Partnership infrastructure  Projects. A Case Study of Niger-Delta Region of Nigeria. Unpublished PhD Thesis.
11. Law Teacher.net (2024) Benefits and Disadvantages of Variation Orders available at  https://www.lawteacher.net accessed on January 2024
12. Mohammed, A.A (2017) Client Causes of Variation in Construction Projects in United Arab Emirates. A Dissertation submitted in fulfillment of the requirements for the degree of MSc Construction Management M at The British University in Dubai
13. National Bureau of Statistics (2019) Reports on Employment Share of 18 Industrial Sectors in Nigeria
14. National Bureau of Statistics (2022) Nigerian Gross Domestic Product report Q2. August
15. Noraziah M., Adi Irfan C., and Riza Atiq O.K., (2017). Causes and Effects of Variation Orders in the Construction of Terrace Housing Projects, International Journal of Supply Chain Management, Volume 6, Issue, 1, PP 226-223
16. Oyewobi, L. Jimoh, R. Ganiyu, B.and Shittu,A.(2016) Analysis of Causes and Impact of Variation Order on Educational Building Projects. Journal of Facilities Management vol. 14, (2), 139–164, doi: 10.1108/JFM-01-2015-0001
17. Pokharel A. R. and Joshi, B. R. (2020). Impact of Variation Orders on Construction Project Cost: A case study of Land Pooling Project at Kathmandu of Ichangu Narayan, Nepal. Saudi Journal of Engineering and Technology, 5(5): 203-230. Published by Scholars Middle East Publishers, Dubai, United Arab Emirates.
18. Suleiman I. J. and Luvara V. G. M. (2016). Factors Influencing Change of Design of Building Projects during Construction Stage in Dar-es- Salaam Tanzania. International Journal of Construction Engineering and Management, vol. 5, no. 4, pp. 93–101.
19. Designing Buildings Wiki (2023) Variation in Construction Contracts available at https://www.dasigningbuildings.co.uk  assessed on December 2023
20. Yadeta, A. E. (2016) Causes of Variation orders on public Building projects in Addis Ababa, International Journal of Engineering Research and General Science, vol. 4, no. 4, pp. 242–250, 2016.