Advantages and Disadvantages of Prefabricated Structures

If you are looking for advantages and disadvantages of prefabricated structures and construction then you came to the right place. The structure is made up of different elements. These elements are manufactured during the construction of the structure and on-site.

However, in order to eliminate construction difficulties, not to depend on the season and conditions, and to ensure that the work is completed quickly and quickly, the structural elements can be fabricated on-site or away from the construction site.

Structures built by combining pre-manufactured elements in a suitable way are called prefabricated structures.

Elements such as floors of structures, roof plates, beams, columns, rigid frames, wall panels, arches, domes, load-bearing walls can be made as prefabricated. All kinds of industrial structures, residences, commercial structures, art structures, port elements, retaining walls, auxiliary facilities are built with prefabricated elements.

The whole structure can be built as prefabricated, some of it can be built in situ and some of it can be prefabricated.

The prefabricated construction method has many advantages. These advantages are; are classified under the headings of quality, cost, time, safety, cleanliness, regularity, and ecology.

Here are the Advantages and Disadvantages of Prefabricated Structures:

Advantages of Prefabricated Structures

Quality

  • High-quality products can be produced in a controlled production environment with high mechanical technology.
  • Qualified personnel specialized in a particular job increase efficiency and reduce errors.
  • Thanks to planning, the effects of weather conditions are minimized.
  • With industrial construction systems, quality surfaces can be obtained in structural elements.
  • Repetition in production brings specialization.

Cost

  • Labour in the construction area is significantly reduced.
  • Waste materials are significantly reduced and can be reused.
  • Molds can be used many times.
  • Thanks to the production quality and control, the correction work of the product is significantly reduced.
  • Since the loss of time due to climate is prevented, the construction process is shortened.
  • Due to the speed of the production process, it is less affected by inflation.
  • Elements capable of effective insulation can be produced.
  • In prefabricated construction, the risk of going out of the planned budget is less.

Time

  • The construction process has been significantly reduced thanks to offsite production and simplified installation details.
  • Within the time planning, the construction process has a manageable schedule.
  • Construction components can be produced during earthworks and shorten the construction time.

Security

With the machine-intensive construction process, labor is minimized; a safe and systematic working environment is provided.

Cleanliness and orderliness

  • The systematic storage and use of components and materials ensure a clean structure site.
  • Consumption in the construction area is reduced.
  • Support and formwork materials are used at a minimum level.

Ecological

  • With the prefabricated construction method, the material consumption is minimized and raw material and energy resources can be utilized at the maximum level.
  • As the work is done at the construction site decreases, the discomfort, and pollution to the environment decrease.
  • With the rational solution of the details, products that provide effective insulation can be produced. These energy-efficient elements contribute to carbon emissions.

Other Benefits of prefabricated structures

  1. The construction period is shortened and the structure becomes usable in a short time.
  2. It provides standardization in construction methods and structure elements.
  3. It provides the recovery of construction activities from climate, weather conditions, and external effects.
  4. It ensures the most efficient use of brainpower, workforce, machinery, and equipment, minimizing idle capacity, and minimizing the performance-reducing factors in these powers.
  5. It minimizes material labour and energy losses.
  6. It eliminates the conditions such as shrinkage, poor manufacturing, damaged surfaces that reduce the quality of the structure.
  7. It minimizes the transportation and storage of all kinds of materials.
  8. It provides the selection of construction methods that will allow planning and implementation to foresee and cover every stage of the application.
  9. It is possible to make the elements in the desired quality.
  10. It is possible to construct more economical structures under favorable conditions.
  11. During the production of reinforced concrete prefabricated structure elements, the mold costs are reduced thanks to the mass production made on the molds that are set up once.
  12. The absence of significant differences between the expected cost and the actual cost during the production phase of reinforced concrete prefabricated structure elements or remaining within the specified budget.
  13. The structure, which is produced from reinforced concrete prefabricated structure elements, is ready to be sent to the construction site as soon as it is formed and it is completed in a shorter time compared to the traditional construction, providing the investor with the opportunity to rent or sell early.
  14. Reduction of costs related to labour, mold, and material in production.
  15. Thanks to the benefits provided by the prefabrication technology, the workers can continue their work as the construction can continue in the winter months.
  16. There is no storage cost as there is no need for pre-purchasing, stocking, and storing the materials required for manufacturing.
  17. It is much less affected by inflation due to mass production and high production speed.
  18. The increase in the speed of production in factories; Efficiency increases due to minimizing material loss and obtaining the highest efficiency from labor.
  19. The production of reinforced concrete prefabricated structure elements carried out in closed conditions is not affected by climatic conditions; the fact that the carrier element can be produced in the factories while the necessary infrastructure works for the project work is carried out in the construction site environment; precise determination of work schedules and anticipation of possible delays due to stable production; It greatly shortens the construction period of the project.
  20. Thanks to its continuous production, specialization in the construction of prefabricated structures is achieved.
  21. Even if the assembly site is not ready, the production in the factories can be continued.
  22. Prefabrication; Due to its structure prone to programming, planning, and control, it provides high quality and can be economical.
  23. During the production of prefabricated reinforced concrete structural elements produced in factories, curing conditions, which are very important for concrete strength, are provided in the best way.
  24. In traditional methods, it is possible to raise the quality standards in prefabricated structure elements by producing by considering difficult weather conditions and environmental conditions.
  25. Thanks to the quality of the construction elements produced in the factory environment, the finished elements are long-lasting.
  26. It is suitable for pre-stressing techniques and has the opportunity to pass large spans, which is of great importance for industrial structures.
  27. The number of workers employed in the production of prefabricated structural elements made in the factory environment is less than the products made in the construction site environments, and the workforce is utilized more efficiently by reducing the work accident with the inspections.

Disadvantages of Prefabricated Structures

Besides the advantages of the prefabricated construction method, there are also disadvantages. Disadvantages; classified in terms of economic, social, technical, and aesthetic.

Economic

  • Prefabrication requires large economic investments.
  • Prefabrication requires regular and systematic financial power. For this reason, small and medium-sized construction investors have difficulties in using prefabrication.
  • The transportation cost may move away from rationality after a certain distance.

Social

  • With prefabrication, there is a possibility that the need for manpower will be lost as a result of high levels of mechanization and unemployment will increase accordingly.
  • There is a need for qualified people during production, design, and construction.

Technical

  • Prefabricated components can be damaged during shipping. Therefore, the elements must be moved. The connection details of the prefabricated elements should be well resolved and resistant to corrosion.
  • Large prefabricated components require heavy handling-assembly equipment and precise measurement.

Aesthetic

  • Prefabricated structures made of the same type of components may appear monotonous.
  • Modular coordination, which is a requirement of rational construction, can limit design flexibility.

Other Disadvantages of prefabricated structures

  1. There is difficulty in adding elements in the form of assembly to each other.
  2. Elements are difficult to move. (They are heavy.)
  3. Production is always made with qualified personnel.
  4. The difficulties for small construction investors to use prefabrication because it requires a systematic and regular economic power.
  5. Lack of economically strong investors.
  6. With the rapid increase in mechanization in the construction sector, the possibility of a great decrease in the use of manpower and an increase in the unemployment problem.
  7. It is stated that the suitable transport distance of prefabricated structural elements is between 100-200 km, and in some countries, even longer transport distances can be efficient. At transportation distances longer than these distances, prefabricated structures lose their economic suitability due to transportation prices.
  8. Some problems may arise in the strength of the prefabricated structure system under earthquake and dynamic loads.
  9. The need for large areas for prefabricated production in factories and the high economic power required for the establishment of a factory.
  10. The absence of a national control mechanism in the production of prefabricated structure elements and the lack of state policies in this regard.
  11. The need for workers with a qualified workforce in prefabricated construction works during production, construction and design phases is quite high.
  12. Coordination problems of production and assembly teams have negative consequences such as transportation and stocking problems.
  13. Joint points, reserve capacities, and ductility present problems not found in cast-in-situ concrete.

Considerations in the Use of Prefabricated Elements

  1. The prefabricated element factory should be located at a maximum distance of 500-600 km from the construction site.
  2. Column axis intervals should be chosen in accordance with the standard and in such a way that the most elements can be used.
  3. Measures should be taken against horizontal loads and earthquakes, and the foundation and upper parts should work as a frame.
  4. Standard sections manufactured at the factory should be used in the project.
  5. There should be no obstacles to the transportation of the elements to the construction site and their assembly.
  6. Roof slopes should be determined by taking into account the reverse deflection of the prestressed elements.
  7. The forces at the junction points should be studied.
  8. There is an obligation to put joints between more than one prefabricated element.
  9. The same combination should be used as much as possible to ensure standardization.
  10. It is necessary to make it ductile so that the junction points are not affected by loads, effects such as breaking, breaking, and capacity reduction.

Barriers to the Development of Prefabrication

When the use of prefabricated structural elements in the construction field in Turkey is compared with the use of prefabricated construction elements in the world, it is seen that our country lags far behind. The substances that negatively affect the low usage rate and development of prefabrication are listed below:

  1. Believing in the judgment that the production cost of prefabricated structural elements is more expensive than the production cost with traditional methods.
  2. Since the products in the construction industry are more durable and long-lasting than the products in other industries, they cause a decrease in the amount of production after a certain time.
  3. Prefabricated structure users are not satisfied with the low performance of prefabricated structure elements, both architecturally (humidity, cracks, lack of creativity in design, etc.) and structural (poor performance under earthquake load, etc.).
  4. The use of prefabricated elements within a certain system and standard, not being able to meet the desired aesthetics and mobility, the restrictions it brings to architecture, and the realization of the same type of plans in regions with different economic and social characteristics cause the system to receive great criticism (Taş, 2004).
  5. The heavy and large size of the prefabricated reinforced concrete carrier elements and the distance between the construction site and the factory in many places cause the transportation cost to be high.
  6. Concerns about the reliability of the performance of prefabrication systems under different seismic loads.
  7. The lack of communication between the designer, the contractor, and the manufacturer within the scope of the management of the project can negatively affect the construction processes.
  8. The fact that prefabricated structure systems are not supported by the state does not limit their use (Taş, 2004).
  9. Physical barriers such as the unqualified structure of the workforce, insufficient production, and low capital accumulation.
  10. Inadequate engineers, contractor construction companies, and experienced workers during the project design of prefabricated structure elements