ANALYSIS OF THE INFLUENCE OF ORDER VARIATION FACTORS ON THE COSTS AND TIME OF IMPLEMENTING CHANNEL DIVERCTION INFRASTRUCTURE CONSTRUCTION PROJECTS IN RESIDENTIAL AREAS

Tangerang is a big city in Indonesia. The housing sector rocketing in this region. Changes in development often occur because problems arise and have an impact on costs and time. Researchers focused on finding the cause of the work diverting residential channels being hampered. For this reason, changes were made to the sheetpile design and changes to the infrastructure mobilization method to meet the contract time. The research uses the SEM PLS method to determine the factors causing order variations. In addition, the data processing application was used to determine the effect of order variations on time and cost performance. The respondents were 60 owners and consultants. Based on the results of the cost performance analysis, additional work arising from order variations reached 10,516,305,346 IDR and reduced work due to order variations reached 6,628,461,533 IDR or around 12.96% of the initial contract price and the results of time performance analysis for time losses that occurred due to order variations on the project showed an additional time of 5 months or 125%.


Introduction
According to Malik (2010), understanding own project inform that the project has a final product (output) in the form of goods or services obtained from the results of a number of transformations source power (input).Transformation process input become output is carried out over the term time certain (limited) with cost and established quality by letter employment agreement.According to Santosa (2009), a project is defined as a series of activities unique things that are interrelated to achieve a certain result and are carried out in a certain period of time too.Construction Project Management is a science and concept for carry out and complete a construction project so that the work is on time, at the right cost and at the right quality (Mahyuddin, 2023).
According to National Standardization Agency ("National Standardization Agency.Procedures for Planning Residential Environments in Urban Areas Frick, Heinz. 1984. Simple House. Yogyakarta: Kanisius Publishers.," 2004) housing is a group a house that functions as a residential environment, equipped with facilities and infrastructure.Housing is part of settlements, both in urban areas and rural areas (Law of the Republic of Indonesia Number 1 of 2011 Concerning Housing andSettlement Areas., 2011).
According to the American Institute of Architect (AIA) Variation Order is a written request signed by the architect, contractor, and owner made after the contract is issued, which has the authority to change scope of work or making adjustments to the contract value and time completion of work.Another meaning of variation order is an official document signed by the owner and contractor to provide compensation to contractor against changes, additional work, delays, or other consequences other than the collective agreement written in the contract (Barrie & Paulson, 1976).
A variation order will change the original work because changes to improve the original work during a construction project are unavoidable (Yadeta, 2010).Variation orders will be made for a reason and the frequency of changes to work instructions during the construction phase will likely result in significant changes to the original works contract, which will have a negative impact on all parties involved in the sector (Mohammad et al., 2022).Variation Orders is often a reason for construction projects exceeding projects budget and delays it is a global problem (Alhadithi et al., 2021).These variations often cause disputes and dissatisfaction between the parties involved Variation orders cannot be avoided in construction projects, change problems will disrupt cost and time performance because they will increase (Mohammad & Hamzah, 2019). in a construction project.Therefore, controlling VO in a construction project is very important (Memon et al., 2014).This variation order must be recorded so that they are aware that they must pay attention to the clauses relating to the contract, because misinterpretation causes disputes (Hardjomuljadi, 2016).Variation orders on construction are an important part issued to accommodate changes in the value of contract documents (Syal & Bora, 2016).Inconsistencies variations orders have significant implications for project success which can result in work not being completed on time or even trigger cost overruns (Tuloli et al., 2021).
The impact of cost overruns is the loss of a profit margin due to incomplete construction of a construction project (Wen et al., 2022).Tangerang is one of the big cities that is developing in Indonesia.Along with the development of the city, one sector that is increasingly developing is the housing sector.Housing growth does not only occur in a few sub-districts, but in almost all sub-districts in Tangerang City.Most city residents choose to live in housing.Housing development projects are urgently needed because of the availability of high quality and affordable accommodation to meet the housing needs of the population at any time (Mohammad et al., 2022).
This research is located in the Tangerang area on this project consisting of housing developments as many as 734 units House And 14 shophouse units.Researchers focus to work channel diversion infrastructure on the project housing where the initial contract value This work is 16,150,000,000 IDR over time implementation 18 weeks as well as wide channel 8 meters and long 427 meter channel there is variation order on items Sheet pile work becomes secondary pile, DPT and gabion.
The objectives of this research include: to obtain and analyze the dominant factors that cause variation orders to occur in construction project performance in channel diversion infrastructure projects in residential areas, analyze the influence of these variables on performance values in channel diversion infrastructure projects, analyze the magnitude of the influence of variation orders on cost and value performance values time performance, analyzing the results of previous research with current research and as a source of knowledge and useful for further research.
That happen exists a problem where the unit developer cannot be built houses in the plot area as well there is a position for an electrical substation for flow supply electricity several house units in areas housing area the due to planning beginning which not good so that will be a problem for handover to customers so it will impact to implementation of project activities construction and influence on costs and implementation time and will reduce interest in developers so this research needs to be carried out.Feasibility studies are very important in determining whether or not a construction is worth building, how impact on the environment, away from facilities general (Rani, 2016).The construction of housing projects by private parties, especially due to their small size and scope, has not received sufficient attention from professional researchers around the world (Koushki et al., 2005).
This research "Analysis of the Influence of Order Variation Factors on the Cost and Time of Implementation of Channel Diversion Infrastructure Construction Projects in Residential Areas" is research made as a reference recommendation for project performance in this case, especially residential construction projects for channel diversion infrastructure carried out by private parties.From previous research, the author tries to complete the analysis of different case studies, namely discussing the factors causing variation orders, especially in residential channel diversion infrastructure projects.factors that influence project performance on costs and time which might be a solution or minimize risks on the next project.

Research Methodology
Research using a survey method was carried out to find out what factors just which be the cause variation order and how influence to performance project costs and construction implementation time on infrastructure projects channel switching on housing area.The questionnaire distributed to previous respondents via process expert oinion first.
Factors which this causes the variation order for the survey method to be formulated as 2 (two) mutual variables influence that is the dependent variable is the variable that is influenced, namely project performance and the independent variable (independent variable) as variable that affect variation orders namely contract document factors, planning And design factors, owner involvement factors, condition environmental or external factors, contractors factors and resources factors.
Variable values will be measured by using techniques Likert scale measurements that is in form factor of sequence occurrence variations that influential on performance project, on scale measurements (Albtoosh, et al., 2017): 1.Not one 2. Very seldom 3. Seldom 4. Often 5. Very often The survey data that has been obtained will then be processed using the SEM PLS method to determine what factors are dominant in order variations in channel diversion work in residential areas.Furthermore, stages in this research, namely gather data tabulation which is obtained from respondents that is factors the cause variation order on the project diversion channel in residential areas that affect cost and time performance.Results from data then analyzed with use SEM PLS 3.3.3.To determine change cost and time which happen in analysis by using Microsoft Excel with calculations as follows:

Research Results and Discussion
Based on literature which has been grouped together according to topic the discussion that will be researched is regarding aspects of factors that cause variation order on project performance, the researcher found a research gap based on the results of the research theme previously.This research gap is an analytical study carried out on research on channel diversion infrastructure work, especially in housing projects.Case studies of channel diversions in residential areas are very rarely found in housing project areas so this research needs to be carried out so that in future projects the same thing does not happen which will have an impact on costs and implementation time, especially in housing development projects.The results of expert validation that have been carried out on indicator questionnaires for factors that cause sequence variations in diversion project channels in residential areas that will be used in this research.The number of questionnaires available is 37 variable indicators that have passed expert validation for 42 research indicators except for indicators X1.2, X1.4,X1.5, X6.5, X6.6.Data related to the characteristics of the respondents about related parties can be seen in figure 5, education background can be seen in figure 6, and work experience can be seen in figure 7.This have two value criteria which will evaluated that is loading factor value and mark average variance extracted factor (AVE).Entire indicator for every variable has mark loading factors above 0.7.With thus, the indicators of each measuring variable study this has categorized as valid.Entire indicator for each variable has mark AVE above 0.5.Thus, indicators each this research variable has categorized as valid according to Hamid & Anwar (2019).

Discriminant Validity Test
On this stage there is two value criteria will evaluated namely the cross loading value and mark correlation between constructs latent.Variable document contract, owner involvement, conditions environment and external, planning and design, contractors, and resources have mark correlation between variables latent more small from the root value square AVE, so it can be interpreted that construct is categorized as valid according to Hamid & Anwar (2019).

Reliability Test
On SEM PLS stage test construct reliability done with look at the composite value reliability.Results all mark composite reliability is above 0.70 then it can be concluded that the document contracts, owner involvement, performance project, conditions environment or external, contractor, planning and design and resources have reliability which good or reliable category (Hamid & Anwar, 2019).Results significant to project performance greatly influential to indicator Y1.1 that is influence on project cost performance is 32.145 with influencing variables significant, namely planning And design on dominant indicators X2.7 namely changes to planning drawings with mark amounting to 14.282And environmental or external condition variables in the dominant indicator X4.1, namely the item reducing or postponing the construction part regarding the problem environment with value of 29.931.Document contract influential negative and not significant to project performance, therefore that in job change (variation order) factors because the existence of document variables the contract does not affect performance projects and variation orders.This supports previous research by Aliyudin & Susetyo (2023) and Hansen et al., (2020) which stated that contract documents do not influence the factors causing variation orders.That variation orders can occur in the contract document factor, namely because they do not explain in detail and in detail regarding the contract for the work so that there is a difference between the contract document and the drawing document.

Figure 6. Bootstrapping results
Planning and design positive influence and significant on project performance, because it's in a job change (variation order) factor the cause is planning and design variable direct effect to performance project and variations order.This supports research Prasetya & Prasetia (2022), Hansen et al., (2020), Viswanath & Kumar (2017), Alzara (2022), Arain & Pheng (2006), Enshassi et al., (2010), Nurmala & Hardjomuljadi (2015), Palilati et al., (2022), Murtopo et al.,(2022) which states that the factors causing variation orders to occur are planning and design due to lack of detailed planning and not in accordance with field conditions and a feasibility study has not been carried out to minimize design changes which could result in changes in time and additional costs.
Involvement owner negative influence And No significant to performance project, because in change work (variation order), owner involvement variable does not affect performance projects and variation orders.This is contrary to research Putri & Waty (2021), Septian & Herzanita (2021), Widhiawati Ida Ayu Rai, Anak Agung Wiranata (2016), Elshaikh & Mahmoud (2020), M.karim et al., (2020), Mohammad et al.,(2017) which states that the owner involvement factor or owner factor (owner) causes variation orders to occur due to requests or policies from the owner both in determining material specifications, environmental conditions, schedules and the owner's inability.
Condition environment or external influence is positive and significant to performance project, therefore in change of work (variation order) factor the cause is because environmental conditions or external variable direct influence to project performance and variation order.This supports research from Putri & Waty (2021), Widhiawati Ida Ayu Rai, Anak Agung Wiranata (2016), Muluk et al., (2018), Kustiah et al., (2022), Maulana (2016) which states that environmental conditions or external factors cause order variations to occur.due to problematic factors related to land acquisition in the project area, socio-cultural conditions of the community around the project, as well as third party interference.
Contractors have positive and negative influences significant to project performance, therefore in job changes (variation order), there are no contractor variables affect performance project and variation order.This supports research Muluk et al., (2018), Riswandi et al., (2021), andMohammed, et al. (2017).However, the results of the research conducted are that there is poor project planning and scheduling by contractors Resource has negative influence and not significant to performance project, therefore it's on a job change (variation order) the causal factor is due to variables resource has no direct influence on project performance and variation order.This supports research Septian & Herzanita (2021) which states that resource factors do not influence the occurrence of order variation.
Based on the results of project data processing then: Change cost which occurred due to order variations of 12.96% against price contract early so in category No Good.For work items with changes additional costs which big as well as change less cost which happen on items segment work channel open due to changes drawing of the initial design using a sheet pile changed into borepile, DPT and gabion.Time implementation project diversion channels under the contract are 18 week, from date February 14 2022 until July 14, 2022.But inside there was a delay in implementation, in because: (1) Existence items work which in design by planning consultants & planning team no in accordance with the actual conditions existing in the field; (2) During 2 Sunday project stopped by residents local, because it exists technical problems in implementing sheetpile work; and (3) Existence change design by a planning consultant so takes time to can be realize it in the field for 2 weeks.For the final completion time is agreed upon between party owner And the contractor to complete the extension time during 5 months until November 11 2022 or 125% so in the unfavorable category.

Conclusion
Based on results analysis smart PLS then the variable is obtained reason variation order most dominant and influences performance project is a planning variable and design with changes to planning drawings.Results analysis influence variable on performance project on study this is for variables influential negative and doesn't affect it to project performance as well factor variation occurs orders is a contract document, engagement owner and resources while influential variables positive and affect performance project and the factors in which variation orders occur are planning and design, conditions environment and external as well contractor.
Analysis results cost performance for the amount of cost as a result variation order on additional work total of 10,516,305,346 IDR and for less total work amounting to 6,628,461,533 IDR around 12.96% of the initial contract price for the work so that in category not good.Results analysis performance time for that amount of time resulted there is a variation order on the project work that happens exists extension time for 5 months or 125% so it is in the poor category.

Figure 1 .
Figure 1.Overview of the channel diversion Figure 4. Research model

Table 2 .
Correlation between latent constructs

Table 3 .
Reliability test

Table 6 .
Proportion of variation orders