Constructability assessment of different formwork methodologies using building information modeling

• Main Authors: Apacible, Karl Brian B., Encabo, Maria Camir T., Ong, Jon Ridge L., Tejada, Carl Michael A., III
• Format: text
• Language: English
• Published: Animo Repository 2016
• Subjects: Sheathing (Building materials); Civil Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/8838
• Institution: De La Salle University

The need to minimize costs for projects is very important to construction companies, especially since the industry is only getting more and more competitive. While people usually associate being competitive with cost, efficiency is just as important in construction because of the time element present. An efficient method of using formworks can help minimize cost, but going in to deeper analysis is not being done as there is already rules of thumb informally established by the industry. Given this, an easier means determining the most efficient methodology for formworks is needed. In the Philippines, plywood and phenolic boards remain to be the most commonly used sheathings to give shape to concrete structural elements. Some contractors have begun using steel formwork through it is not a practice commonly utilized by the country's engineers. It is common knowledge that steel formworks should encourage better productivity, but the barrier to using it is in its cost. This study aims to compare the constructability of formwork methodologies that use traditional formwork systems with those that use a mixed formwork system in the construction of low-rise structures. It was done by analyzing the labor productivity and cost quantitatively in order to compare the two parameters and determine if the added cost can indeed justify the increase in productivity. A total of 10 projects were observed. Five projects made use of a traditional formwork system (method A), and the other five projects made use of a mixed formwork system (method B). The labor productivity was first obtained through observations and recorded logbooks from the project sites. Then using these labor productiviteis of each project, the projected total duration of formwork activities, assuming that the productivity rate is constant, is obtained with the aid of BIM. Also, the process cost was determined through BIM using the commercial price lists and the productivity rate. All these parameters were tested using t-test to determine the difference between the two formwork systems. As a result, only the slab elements has the significant difference between the two methods in terms of labor productivity, duration and process cost. It is determined that method A is 31.42% slower than method B, but method B is 11.99% more expensive than method A. A cost-benefit analysis was done which showed that the benefit of method B over method A starts to outweigh the costs of moving from method B to method A at a total formwork surfaces ara of 5,249.43 m2 to 9,711 m2, with a 60% confidence level. This analysis only considers labor cost savings as benefit and thus excludes other possible sources of monetary benefit that are circumstantial to different projects.