Comparison Analysis for Implementation Time of Column Formwork Using Three Formwork Methods in a Building Project at Bandung Province

The construction world, especially in modern times, technological innovations are developing rapidly. One of these innovations is formwork. The real proof of its development is the formwork method, which has an increasing number of types. This study describes the time comparison between the three formwork methods consisting of conventional, semi-system, and full system formwork for column work on the UPI Bandung multi-storey building project. The research method that has been done is quantitative. The analysis is carried out by calculating the volume of work, identifying the coefficient of workers from journals and articles, calculating labour productivity and then the duration of work for each formwork method can be calculated. The results obtained from this study regards the duration of work on each formwork method column in each building studied. In conclusion, the duration of column work with the conventional formwork method has the longest duration of work, followed by the semi system method and the full system method.


Introduction
In an era where sustainability development is growing, one of the sectors that is affected by the effects of development is the world of construction.The field of sustainable development can be split in three categories: environmental sustainability, economic sustainability, and socio-political sustainability [1].In regards of concrete works, the use of formworks is plenty, so to find a sustainable solution to formworks design is important in eco-engineering and sustainable development of construction.Ahmed et al. [1] said that attaining a sustainable formwork system has the potential to drive greater sustainability in construction practices, ultimately strengthening the construction industry's role in promoting sustainability for the well-being of future generations.
The formwork itself can be grouped based on the type of material, its use, and the method of movement during the casting process.In a building structure formwork has a role as a temporary mould to hold the load during the casting and hardening process of the concrete so that it can be shaped according to the desired shape.Because the formwork has the role of a temporary mould, it will be removed and dismantled after the concrete has hardened and has sufficient strength and is load-bearing the structure and is formed according to the mould.In selecting the type of formwork that is appropriate for a construction building project, it must be considered in detail because the type of formwork will 1324 (2024) 012032 IOP Publishing doi:10.1088/1755-1315/1324/1/012032 2 directly affect it in terms of cost, project schedule, time to use the formwork and the quality of the construction itself [2].
One of the factors that became the reason for conducting this research was the lack of information regarding which formwork method is suitable for use in multi-storey building projects so that the project schedule time wise is not hampered by choosing the wrong formwork method.In this study, the authors wanted to analyse the three formwork methods, namely conventional, semi-system, and full system.The difference between these 3 methods can be seen from the materials [3].From these three methods, it is hoped that the type of formwork that has a fast duration of work can be identified to be used for column formwork in multi-storey buildings.By choosing the right formwork method, it will improve the quality of the work and speed up the planned project schedule, by doing this a more sustainable construction is easier to achieve especially with the capability for repeated use of formworks.This research was conducted at PT. Hutama Karya in the context of joint research regarding the design of standardized use of formwork.for the location of this project to be precise at the Universitas Pendidikan Indonesia, this project consists of three buildings planned to be built: post-Graduate building, Faculty of Education and Economy building, and Faculty of Art Education and Design building.

Literature Review
Formwork or also known as temporary moulding, concrete is held in place when poured and moulded into the desired shape.The formwork will then be taken down and dismantled once the concrete has attained sufficient strength [4].

Work Volume
The volume of work is needed to determine the implementation method for formwork structure.This includes the analysis of work volume in each structural element with the requirements for reinforcement, formwork and concrete volume are used as a reference.The calculation of the volume of work is carried out based on shop drawings, where shop drawings are used as benchmarks in determining quality, scope of work and budget plans [5].The work volume is compiled using a table format with grouping according to the scope of work so that it is easier for identification.Calculation of the volume of work can be done in various ways such as net measurement, and gross measurement.Calculation for work volume can be made into volume work units per m 3 for the concrete volume.The volume of the work unit itself can be divided into the total need for reinforcement and formwork to 1 m 3 volume of concrete.With this method of calculation, workers in the field can estimate the volume of reinforcement and formwork that has been used based on the volume of concrete in each work element [6].If the volume of work has been determined according to the quantity surveyor consultant's calculations by the assignor, the contractor will charge the excess difference in the calculation to the unit price of the work.

Labor Productivity
Productivity is referred to as the ratio of production output to all inputs, or production output to the total resources used.The productivity ratio is one of the values measured during a building project.Resource management efficiency determines the success or failure of a building project.One of the resources that is difficult to control is labour.The level of worker productivity is influenced by various factors.Productivity checks and influencing factor checklists are added to workforce planning because projects typically take place in a variety of settings.For example, the geographical location of a project, climate, qualifications and expertise of project team members, or relevant legislation all contribute to this variable or factor.The number of workers is strongly influenced by labour productivity.If labour productivity is higher than the number of workers is lower, and vice versa [7].To find out the factors that affect labour productivity, such as analysing labour productivity against time performance on projects [8].Labour productivity can be calculated through worker coefficient OH (operating hour).In this research there are several worker coefficients for different type of formworks, there are conventional, semi system and full system formworks, as seen on Table Then following is a way of calculating labour productivity that will be applied to this research as [11]: After calculating labour productivity, the next step is to calculate the number of workers needed in one work group, the following is the formula for the number of workers: The next step, by calculating productivity and the number of workers, therefore the author can calculate the duration of each floor of the building, which is divided into three zones per floor, below is the calculation method to find the duration of the column formwork work as follows:

Work Volume
Labor Productivity ×Total Labor (3)

Project Scheduling
In carrying and making out project scheduling, several factors must be considered and planned properly so that the objectives in completing the project can be achieved, namely cost, quality and schedule.Project management is needed in planning, implementing, controlling projects and is also important so that these three things can be carried out according to the plans that were made before the project started.Project scheduling itself is one of the planning activities for the time span of a project.Scheduling starts with identifying the types of activities, the sequence of the work and planning how long it will take to complete each project work [12].Microsoft project is a software that has a function, one of which is planning in scheduling a project or series of work.This software can also observe and record all activities using human resources or project equipment.

Research Method
Figure 1 shows the general flow of this research.The first step taken in this study was to identify the problem, objectives, and research limitations regarding the analysis of the formwork method in terms of time between Conventional, Semi System, Full system (PERI).After that, reviewing the theoretical basis containing literature from journals, books, and articles with topics according to the.Furthermore, collecting primary data obtained from direct field observations and secondary data obtained from articles and journals, data obtained from projects in such as implementation methods and column formwork work schedules, shop drawing and worker coefficients obtained from journals and other resources, then calculating and recapitulating column dimensions.Then, do an analysis in terms of time between the three formwork methods using Microsoft Excel and Microsoft Project regarding the scheduling and sequence of formwork work according to the formwork method used.The results are then compared between the three formwork methods.A conclusion and suggestion can then be obtained.

Results and Discussion
There are three building analysed, there are: post-Graduate building, Faculty of Education and Economy building, and Faculty of Art Education and Design building.Each building has its own zones split into three zones, as seen on Figure 2. The first step is to find the volume of the columns (work volume) for the formworks.Based on shop drawings, it can be concluded that for each building the volume of column can be seen on table 4, to Table 6

Analysis on the Duration of Each Formworks Methods
After the volume is calculated, with worker data, productivity data, and work items then the duration for each formwork's methods can be calculated and analysed.This analysis was taken using both MS excel calculation and MS Project calculation as validation.The tables below show the duration for the various methods on the three buildings.

Time Calculation for Each Formworks Methods
To validate and check the results of the calculation, more analysis was taken using MS Project for Semi-System and Full System.For conventional method, because of the lack of data and information from the project itself, an analysis using MS Project cannot be done accurately as it required too many assumptions.Works Duration Comparison Between Each Methods can be seen on Figure 4, as it shows the recapitulation of the durations (from the time analysis above) for Formworks in Post-Graduate Building, Faculty of Education and Economy Building and the Faculty of Art Education and Design Building.Based on 3 graphs on Figure 3, 4, and 5 which are recapitulating the duration of work between the 3 methods, the full system has the fastest duration among the three formwork methods reviewed because this method has the highest labour productivity value of the three formwork methods, the greater the value of labour productivity, the faster the duration of the formwork work.
After carrying out calculations and analysis of the duration of the column work, validation was carried out on the results of the calculation of the installation and dismantling duration of the column formworks with the data provided by project location and previous studies that calculated the duration of column work using conventional, semi-system and full-system methods.
In post-graduate buildings, installation and dismantling of column formwork from the results of calculations and based on the graphs in Figure .3 the full system method has a faster duration than semisystem and conventional methods.The full system method takes about 29% less time than the semi system method.Meanwhile, the full system method takes about 21% less time than the conventional method.
At the Faculty of Education and Economy Building, installation and dismantling of column formwork from the results of calculations and based on the graphs in Figure .4 the full system method has a faster duration than semi-system and conventional methods.The full system method takes about 21% less time than the semi system method.Meanwhile, the full system method requires 17% of the duration of the conventional method.
At the Faculty of Art Education and Design Building, the installation and dismantling of column formwork from the results of calculations and based on the graphs in Figure .5, the full system method has a shorter duration than semi-system and conventional methods.The full system method takes about 22% less time than the semi system method.Meanwhile, the full system method requires 15% of the duration of the conventional method.
From the results of the 3 column formwork methods, when compared with the actual work duration data provided by the Project Location, based on the author's calculations, the duration of work for the full system method in the postgraduate building takes 20.9% faster than scheduling the duration of the full system method original data from Project Location The duration of work for the full system method in the education and economics faculty building takes 24.5% faster than scheduling the duration of the full system method of the original data from Project Location.
The duration of work for the full system method in the education and design faculty building takes 21.4% faster than scheduling the duration of the full system method of the original data from Project Location.
When compared with previous studies with for example the recent study called 'Analisa Perbandingan Penggunaaan Bekisting Alumunium, Bekisting Konvesional, Semi Konvensional Dan Sistem (PERI)' [13].The duration of the full system installation takes about 66% faster than the conventional method, while the comparison of the full system method is 80% faster than the semi system method.

Figure 2 .
Figure 2. Post-Graduate Building (Upper) Faculty of Education and Economy Building (Middle) Faculty of Art Education and Design Building (bottom)

Figure 3 .
Figure 3.Comparison of Work Duration for Each Formwork Methods at Post-Graduate Building

Figure 4 . 8 Figure 5 .
Figure 4. Comparison of Work Duration for Each Formwork Methods at Faculty of Education

Table 3 .
Worker Coefficient for Full System Formworks

Table 4 .
: Work Volume for Post-Graduate Building (Three Zones)

Table 5 .
Work Volume for Faculty of Education and Economy Building (Three Zones)

Table 6 .
Work Volume for Faculty of Art Education and Design Building (Three Zones)

Table 7 .
Method Using data from work volume, worker coefficient, worker (labour) productivity and total worker (labour), the results can be seen on table 7: Duration of Conventional Formworks Method for the Three Building

Table 8 .
Duration of Semi System Formworks Method for the Post-Graduate Building Full System Formworks Method Using data from work volume, worker coefficient, worker (labour) productivity and total worker (labour), the results are as follow can be seen on table 9:

Table 9 .
Duration of Full System Formworks Method for the Post-Graduate Building