Comparisonal Analysis of Formwork Costs Conventional, Semi-System and Aluminium on Shear Wall Work (Case Study: The Building of The Faculty of Art and Design Education)

. Indonesia is one of the other countries with a high productivity level in the construction industry. As the construction industry increases, some things must be considered in construction management, namely cost, time, and quality. In this study, the authors focus on the analysis of formwork in terms of cost by using unit price analysis which refers to PUPR and unit prices in each province. This research resulted in an analysis of the formwork method, which is more cost-effective in the shear wall work of the Faculty of Art and Design Education Building. The results showed that using the aluminium formwork method has an average cost of 36% more economical than conventional methods, and semi-system methods.


Introduction
Building and infrastructure construction is still common in both developed and developing countries, one of which is Indonesia.Indonesia is one of the other countries that have a high level of productivity in the construction industry so the construction industry is one of the factors that affect the Indonesian economy.As the construction industry increases, there are things that must be considered in construction management.Cost, time, and quality are things that must be reviewed in the construction management itself.These parameters are always the most important things in the implementation of a construction.
Total construction costs consist of three main cost categories.The first major cost category is construction costs, which include materials, services, and machinery costs, as well as additional costs such as shipping or material management costs.The second major category of costs is incremental costs.It's not directly related to construction work, but something to do with it.This includes design costs, such as pre-study fees, soil mechanics (geotechnical) measurement fees, or legal fees.The third major cost category is also ancillary costs.It can be projected on a per-square meter basis for construction costs, such as interior design, infrastructure, lump sum, or using some special technology, such as warehousing technology [1].
Formwork costs generally range from 35% to 60% or more of the total cost of the concrete structure.Considering the impact of formwork on the total cost, it is very important that the formwork structural engineer also designs the formwork for formation savings, so that formwork planning must be made efficiently, minimizing time and cost, in the construction schedule process for the benefit of contractors and owners [2].These parameters are always the most important thing in the implementation of construction, but in this study, the authors will only focus on the cost aspect.This research will later produce alternative information regarding comparative studies in the use of the formwork method for shear wall work.Therefore, the author wants to further analyze the comparison of costs in carrying out formwork work on shear walls or shear walls using conventional, semi-system, system, and aluminum formwork methods which have been obtained under the title "Comparative Analysis of Conventional Formwork Costs, Semi-system and Systems on Shear Wall Work".This can be used as a reference for construction services in choosing alternative work methods for shear wall formwork in building construction.

Formwork theory and previous research
Formwork plays an important role in assisting the realization of geometry and the development of the strength of concrete elements.It is also one of the main costs in the construction of concrete structures.Formwork is a mold or mold including all supporting structures, which are used to shape and support concrete until it reaches sufficient strength to carry its weight [3].
Formwork is defined as a temporary structure that aims to provide support and resistance until the concrete can support its own weight [4].The materials commonly used in formwork are wood, steel, aluminum, fabric, and plastic with different types and classifications.[5] The system used can be a combination of the two materials.The selection of suitable materials for formwork shall be based on maximum savings to the contractor, consistent with the safety and quality required in the final work [6].Formwork systems can generally be classified as Vertical Systems (walls and columns) and Horizontal Systems (slabs and beams).The material that serves as a formwork surface is known as casing and is used in both vertical and horizontal systems.That formwork material can be declared good if it meets certain requirements [7], such as: There are no leaks and do not absorb water content in the concrete mixture; For concrete with architectural design, formwork must have the texture as planned; Strength of formwork materials must be tested in holding concrete; Can facilitate the formation of precise concrete; Formwork reinforcement must be taken into account.
In general, formwork has different systems, which can be distinguished as the type of formwork itself.Here are some types of formwork that are often used in construction.
a. Conventional Formwork Conventional formwork systems are generally known in the world of construction as the stick form or handover-hand method.[8] Conventional formwork is a formwork system in which when the formwork is dismantled or removed it becomes basic parts, therefore the formwork can be rearranged into another form.Conventional formwork systems include formwork for slabs, beams, and foundations.[9] This system is formed from wood, plywood, or plywood (multiplex), in conventional formwork it can be used three times.
b. Semi-system formwork Semi-system formwork is formwork that is deliberately formed for a certain type of construction.Requirements in using semi-system formwork, the building construction structure must have a symmetrical shape.So that formwork can be used repeatedly [10].While there are other opinions regarding the definition of semi-system formwork itself [11], in general, semisystem formwork is composed of several plate materials.The cantilever construction is composed of factory-made components or steel wooden girders which are arranged and the formwork using the PERI semi-system can be used up to 6 times.
c. Aluminum formwork Aluminum formwork [12] is a formwork that has undergone further renewal to become a universal formwork where this formwork can be used with all possibilities in various types of buildings.Aluminum formwork financing can not only be purchased directly but can also be rented from formwork equipment providers.Aluminum formwork is made of highstrength aluminum, with face or panel contact surfaces, consisting of 4mm thick plates, which are welded to formwork specially designed extrusion sections [13].These formwork panels are held in place by a simple pin and wedge adjustment system that threads through holes on the outside edge of each panel.Panel walls are held together by high-strength wall ties, while the deck is supported by beams and supports [11].Because the equipment is made of aluminum, it has parts that are large enough to be effective, yet light enough for a single worker to handle.

Research method
This study used a quantitative method, in which formwork data were collected from PERI semi-system, conventional, and aluminum formwork obtained through observation at the construction project of the Faculty of Art and Design Education Building, with a review of shear walls.Other data needed in this study were obtained through benchmarking in previous studies.This is done to know the effectiveness of certain formwork methods with cost as a parameter.This research will refer to PUPR Regulation Number 1 of 2022, Journal of Unit Price Books 2022 West Java Province, and related journals regarding Unit Price Analysis and compare several formwork methods, namely the conventional method, the semi-PERI system method, and aluminum in terms of cost.

Data analyis
In knowing the budget plan spent on shear wall formwork in the Faculty of Art and Design Education (FPSD) building, formwork volume data is needed.In this FPSD building, shear walls and columns are one part.So the formula for the area of the formwork used must be slightly modified.The volume of shear wall formwork in the Faculty of Art and Design Education Building can be seen as follows: In addition to shear wall area data, unit labor price analysis data is also needed to be used in calculating the budget plan.The unit prices to be reviewed are the unit prices for materials, tools, and wages, which consist of the coefficient values for each job description, and the unit price for materials.The unit price analysis for shear wall formwork is presented in Table 2. Based on the results of the analysis in Table 3 and Table 4, regarding the costs of shear wall work using several methods, in order to find economic value in shear wall formwork work.In the end, the author can conclude that the costs required for the shear wall work of the Faculty of Art and Design Education Building are shown in Table 5.
Based on the analysis in Table 5, it can be concluded that using aluminum formwork has a more economical cost.Meanwhile, it is inversely proportional to conventional formwork methods which are more expensive than other formwork methods.It can be visualized with the following diagram in Figure 1.The definition of formwork methods that are costeffective can also be defined by comparing formwork methods that have low or economical work costs with other formwork methods.Therefore, there is a cost comparison to other methods, the diagram can be seen in Figure 2.  From the results of the comparison in Figure 3, the comparison of shear wall formwork with conventional and aluminum formwork methods obtains a difference of 48%, while the semi-PERI system method and aluminum obtain a difference of 24%.So it can be concluded that the shear wall formwork work in the Faculty of Art and Design Education Building can be more cost-effective when using the Aluminum method which has an average difference of 36% cheaper than the conventional method and the PERI semi-system method.

Discussion
The analysis of unit prices above can be concluded that in choosing the formwork method for a shear wall job, cheap and high costs depend on the number of floors in the building to be worked on, the volume of the shear wall structure, and the characteristics of the building.According to this study, the shear wall formwork method using the semi-PERI system is more efficient in buildings that have 6 floors with symmetrical structural characteristics, while for above 6 floors, the recommended formwork is formwork with the aluminum method.
Using the aluminum method in shear wall formwork work can be more efficiently used in buildings that have 6 -25 floors.While on top of that, such as in a building with 31 floors, the recommended formwork is a combination of formwork between aluminum and the semi-PERI system.This is because the price of the formwork will be cheap depending on the distribution of the unit price analysis for the application used.As in a building that has 31 floors, because aluminum formwork can be used 25 times, formwork with this method will be used on floors 1 to 25, for the semi-PERI system formwork itself will be used after floors 26 to 31, this is due to residual There are 6 floors to be worked on, therefore the semi-PERI system method can be used on these floors because the PERI semi-system formwork can only be used 6 times.The use of formwork in shear wall work that is more than 6 times, in buildings with the same characteristics as the building for the faculty of art and design education, it is recommended to use the aluminum formwork method.
This study has limitations on unit price data and the coefficients used in each formwork method because researchers only use the coefficients found in other highrise building construction due to limited data on the projects studied.for the future, in researching unit prices, researchers must analyze each job to obtain a valid coefficient according to the consumables contained in the construction building and the recently constructed unit price.because each contractor has different unit prices and coefficients.

Conclusion
Based on the results of the research conducted by the author regarding the comparison of the formwork method in the shear wall work of the Faculty of Art and Design Education (UPI) building project, several conclusions were obtained.The following are the conclusions obtained from the above research: 1.The cost of formwork work on shear wall work in the FPSD building with reference to the West Java Province Unit Price Book, with the conventional method has a cost of up to Rp.559,500,696, for aluminum formwork a fee of Rp.378,021,661 is received, while for the PERI semi-system, it is Rp.378,021,661.2. It can be concluded that for a building with characteristics such as the FPSD building which has seven floors and a symmetrical structure, it is advisable to use the aluminum method for the shear wall formwork work.This is because the cost of work is more effective, compared to conventional methods and semi-PERI systems which have an average difference of 36% more expensive.

Figure 1 .
Figure 1.Diagram of Comparison of Shear wall formwork costs

Figure 2 .
Figure 2. Cost Difference Diagram of Conventional & Aluminum

Tabel 1
Volume Shear wall of the Faculty of Artand Design Education

Table 2
Unit Price Analysis of Shear Wall Formwork (Conventional)

Table 3
Analysis of the unit price for semi-system PERI Shear Wall Formwork

Table 4
Analysis of the Unit Price for Aluminum Shear Wall Formwork

Table 5
Comparison Results of Shear Wall Formwork Cost Analysis