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Project Acceleration Analysis with Crashing Method with Work Shift System
Angga Giovano, Diah Ayu Restuti Wulandari Department of Civil Engineering, Narotama University
Surabaya, Indonesia
Angga0551@gmail.com, diah.wulandari@narotama.ac.id
Abstract
A construction project is an activity whose implementation time is limited and is a temporary activity where before the project is implemented, the beginning and end of the work are usually set. In the implementation of construction projects, various things can happen which can cause an increase in implementation time so that project completion becomes late. Project work delays can be anticipated by accelerating its implementation, but must still pay attention to cost and quality factors, the additional costs incurred are expected to be kept to a minimum. The crashing method is one of the programs used to shorten the duration of a project activity, where the activities that can be carried out are those that are on the critical path, applying the crashing method to the project to determine the optimum duration obtained with alternative work shift systems to anticipate delays what happened in the Project for the Construction of New Classrooms at the Multazam Integrated Islamic Elementary School in Pamekasan, where the scheduling of this project used the microsoft project method. From the data analysis with crashing, the optimum time for work shifts is the acceleration of the project duration from 180 days to 160 days with an additional cost of Rp. 99,666.720.00 of the normal cost.
Keywords:
Crashing Method, Multazam RKB, Project Acceleration, RKB Development, Work Shift
1. Introduction
Execution of work on a project requires not only reliable resources, but also a good management. A construction project can be said to be successful if it fulfills its objectives, namely, it is completed at the specified time, in accordance with the planned costs and meets the required quality. Project management is in charge of planning, leading and controlling existing resources in order to achieve project objectives.
In the implementation of construction projects, various things can happen which can cause an increase in implementation time so that project completion becomes late. The causes of delays that often occur are due to differences in location conditions, design changes, weather influences, lack of fulfillment of worker, material or equipment needs, planning or specification errors, and the influence of the involvement of the project owner (Owner) (Aslinda, 2017).
This research was conducted using the crashing method and using a case study of the Multazam Pamekasan Integrated Islamic Elementary School Construction Project which was chosen due to delays. This project was completed in January 2021 with an implementation time of 180 working days. With the acceleration, it is hoped that the project will be completed on time even faster than the initial plan. This effort is carried out using alternative work shifts.
2. Methodology
The data needed in this study are primary data and secondary data. To obtain primary data in the form of field conditions, problems in the field, and obstacles to project implementation, interviews and direct observation were used. In this study, secondary data needed in the form of project documents, namely RAB, volume of work, list of wage units, and number of workers.
After the required data is collected, then the crashing process is carried out. The acceleration process in this study was carried out by emphasizing the duration of activities on the critical trajectory with additional treatment by means of a work shift system. After knowing the activities that are on the critical path, then the next step is to calculate the cost slope. Crashing is carried out on activities with the lowest cost slope. The crashing process is repeated several times until it reaches a saturation point.
3. Result and Discussion
From the network planning of the Multazam Integrated Islamic Elementary School Pamekasan New Classroom Development Project within the limits for work starting from July 30, 2020, the critical path for bouwplank work and mixed slab concrete work is 1:2:3. So for the next crashing process is carried out on both activities.
3.1. Crashing with Shift Work
Determining acceleration by shift on bouwplank work:
a. Determining labor productivity with a shift system
Shift labor productivity = Prod. normal work/day + ( work product/day – ( work product/day * 11%) Worker = 10,000 + (10,000 – (10,000 *11%))
= 18,900 m/days
Builder = 10,000+ (10,000– (10,000*11%)) = 18,900 m/hari
Foreman = 100,000 + (100,000 – (100,000 *11%)) = 189,000 m/days
b. Determine the duration of work
Job Duration Crashing :
Bouwplank measuring and installation work Worker = = 1.587
Builder = = 1.587 Foreman = = 1.587
Then, we can average and round up to 2 days.
Table 1 . Calculation Results of Alternative Work Shift Crash Duration
Job description Normal Duration Crash Duration
Pek. BouwPlamk 2 1
Pek. Sloof 15x20 8 4
Pek. Kolom induk 20x30 8 4
Pek. Beton Campuran 1:2:3 16 8
c. Determine additional cocts and labor costs 3) Morning Shift Wages
Worker = Rp. 180.000,00 Builder = Rp. 165.000,00 Foreman = Rp. 180.000,00 4) Night Shift Wages
((15% * wages per day) + salary of workers per day) Worker = (15% *Rp. 155.000,00 ) + Rp. 155.000,00 = Rp. 178.250,00
Builder = (15% * Rp. 165.000,00) + Rp. 165.000,00 = Rp. 189.750,00
Foreman = (15% *Rp. 180.000,00) + Rp. 180.000,00 = Rp. 207.000,00
5) Total Labor Wages
((morning shift wages + night shift wages) x duration of work items x number of workers) Worker = (155.000+ 178.250) x 2 x 0,273
= Rp. 181.954,00
Builder = (165.000+ 189.750) x 2 x 0,273
= Rp. 193.693,00
Foreman = (180.000+ 207.000) x 2 x 0,137
= Rp. 106.038,00
Total Wages = Rp. 481.685,00
79 d. Cost Slope
Cost Slope =
Cost Slope =
Cost slope total = cost slpoe per hari x (durasi normal - durasi crash) = 1.516.520,00 x (3– 2)
= Rp. 1.516.520,00
The result of the next Cost Slope calculation is shown in the following table:
Table 2. Calculation Results of Alternative Work Shift Cost Slope
No Normal Duration Cost Slope
Normal Crash
1 2 1 1.516.520,00
2 8 4 2.245.320,00
3 8 4 2.645.050,00
4 16 8 3.398.080,00
3.2. Analisis biaya
After the crashing process reaches a saturation condition and cannot be accelerated, the next step is to calculate the total cost of direct and indirect costs. The following is the calculation of costs as follows:
a. Profit = Total biaya proyek x 6%
= Rp. 1.150.000.000,00 x 6%
= Rp. 69.000.000,00 b. Biaya Overhead = Total biaya proyek x 3%
= Rp. 1.150.000.000,00 x 3%
= Rp. 34.500.000,00 e. Overhead per days =
=
=Rp. 191.667,00
After getting the value of profit and overhead costs, then we can calculate direct costs and indirect costs.
c. Direct cost = 91% * Total biaya proyek
= 91% * Rp. 1.150.000.000,00
= Rp. 1.046.500.000,00 f. Indirect cost = Profit+ Biaya Overhead
= Rp. 69.000.000,00 + Rp. 34.500.000,00
= Rp. 103.500.000,00 g. Total Cost of Project = Direct cost + Indirect cost
= Rp. 1.046.500.000,00 + Rp. 103.500.000,00
= Rp. 1.150.000.000,00
From the calculation of the previous normal cost analysis, the average coefficient value for material costs is 0.83/83% and wage costs are 0.17/17%. Then the weight of material costs and wage costs can be calculated in direct costs on the project.
a. Cost of materials = Direct cost x koefisien bahan
= Rp. 1.046.500.000,00 x 83%
= Rp. 868.595.000,00 b. Wage costs = Direct cost x koefisien upah
= Rp. 1.046.500.000,00 x 17%
= Rp. 177.905.000,00
3.3. Condition after acceleration
1. Direct Cost
Crashing by implementing a work shift system
= biaya langsung normal + cost slope sistem shift
= Rp. 1.046.500.000,00 + Rp. 70.642.000,00
= Rp. 1.117.142.000,00
2. Indirect Cost
Crashing by implementing a work shift system
= (durasi crashing x overhead per hari) + profit
= (160 x Rp. 191.667,00)+ Rp. 69.000.000,00
= Rp. 99.666.720,00
3. Total Project Cost After Crashing
Crashing by implementing a work shift system
= direct cost + indirect cost + profit
= Rp. 1.117.142.000,00 + Rp. 99.666.720,00
= Rp. 1.216.808.720,00
3.4. Examples of Calculation of Direct, Indirect and Total Costs for Shift Work On Work Bouwplank
Cost Slope = Rp 1.516.520,00
Normal Duration = 2
Crash Duration = 1
Total Project Duration = 160
Direct Cost = Rp. 1.117.142.000,00 + 1.516.520,00
= Rp. 1.118.658.520,00
Indirect Cost = (Rp. 99.666.720,00 : 180) x 160
= Rp. 88.592.640,00
Total Cost = Rp. 1.118.658.520,00 + Rp. 88.592.640
= Rp. 1.207.251.160,00
Table 3. Recapitulation of Calculation of Direct Costs, indirect costs and total costs for work shifts
No direct cost (Rp) indirect cost (Rp) Total Cost (Rp)
1 1.118.658.520,00 88.592.640,00 1.207.251.160,00
2 1.119.387.320,00 88.592.640,00 1.207.979.960,00
3 1.119.787.050,00 88.592.640,00 1.208.379.690,00
4 1.120.540.540,00 88.592.640,00 1.209.132.720,00
After direct costs, indirect costs and the total cost of alternative work shifts, the next step is a graph of the relationship between costs and time. This cost and time relationship helps in determining the optimal time and optimal cost for the Multazam Pamekasan integrated Islamic elementary school construction project.
Figure 1. Cost Graph with Alternative Work Shifts 0
200.000.000 400.000.000 600.000.000 800.000.000 1.000.000.000 1.200.000.000 1.400.000.000
1 2 3 4
Cost (Rp)
Type of work
No
Biaya Langsung (Rp)
Biaya Tidak Langsung (Rp)
Total Cost (Rp) Direct Cost
Indirect Costs (Rp)
81
4. Conclusion
This research was conducted on work that is on a critical path which if its implementation is late it will cause delays in the project as a whole. To speed up the duration of the project, an alternative work shift system is used.
Based on the analysis conducted in this study, the following conclusions can be drawn: The total cost of the project under normal conditions is Rp. 1,150,000,000.00 with a project implementation duration of 180 working days.
From the results of the analysis in this study, the total cost of the project in the condition after crashing with the alternative of applying the work shift system (morning shift and night shift) was Rp. 1,216,808,720.00 of the project cost under normal conditions and the duration of the project implementation is 160 days faster than the normal duration.
5. Suggestion
4. In determining the most effective alternative for project acceleration, it can be combined with other factors other than cost and duration factors.
5. For further research should be able to reconstruct network planning so that the resulting time is more optimal.
6. Activities on the critical path need to be given special attention and supervision to reduce the risk of delays in a project.
References
Aslinda Armalisa, 2017 Metode Crashing Terhadap Penambahan Jam Kerja Optimum Proyek Kontruksi. Jurnal CIVITECH, Universitas Serang Raya.
Elisabeth Riska Anggraeni, 2017 Analisis percepatan proyek menggunakan metode Crashing dengan penambahan tenaga kerja dan shift kerja. E-jurnal, Universitas Sebelas Maret.
Ervianto, 2002. Manajemen Proyek Konstruksi, Edisi Pertama. Yogyakarta : Salemba Empat.
