**3.8 Cost separation and building times prefabricated VUF single-family housing and houses with VAC confined masonry**

A comparison has been made between the design of a building with precast reinforced concrete elements and a traditional construction design that is known as confined masonry, it is a system that is traditionally used in Peru and Latin America.

The confined masonry is defined as that which is entirely bordered by elements of reinforced concrete (except for the foundations that can be made of cyclopean concrete and in other cases it is made of reinforced concrete), emptied after the masonry wall has been built and with a distance between columns that does not exceed more than 2 times the height of the floor. It is important to follow the construction sequence indicated so that the confinements adhere to the masonry and form a whole that acts in an integral way [11].

For this reason, six single-family houses built with confined masonry have been designed that have similar characteristics to those of single-family houses with prefabricated elements. That is to say, the architectural plans are similar with regard to the space of the architectural environments, the difference is found in the width of the walls in confined masonry, the width of the wall is 15 cm and in the precast it is 10 cm.

From which the anti-seismic structural calculations with response of equal magnitude have been modeled. Once this similarity was achieved, the metric analysis was then developed, and it was processed in the S10 cost and budget program, in the Microsoft Project and in the SPSS.

#### *3.8.1 Comparison of building times VUF and VAC*

The unit time of VUF Prefabricated Single Family Housing has been determined from 32.07 days in VUF-01 to 65.70 days in VUF 06 and the Time Adjusted with a Gantt chart has been determined from 4.00 days in VUF-01 to 6.00 days in VUF 06.

The unit time of the House built with VAC confined masonry has been determined from 61.11 days in VAC-01 to 136.39 days in VAC-06 and the Adjusted time with a Gantt chart has been determined from 35.38 days in VAC-01 to 79.20 days in VAC 06 (**Table 12**).

The shortest time required for the construction of houses is with prefabricated elements, it is due to the simplicity of the production and assembly process, whereas in confined masonry a dependent, time-consuming and stationary entangled process is required, which leads to lengthening the processes of completion of works.


**Table 12.**

*Unit time (TU) and adjusted time (TA) in VAC Gantt.*

Houses with prefabricated elements require less time for their construction, in unit time values, it takes from 1.10 days/m<sup>2</sup> to 1.24 days/m<sup>2</sup> . With time adjusted in Gantt, values lower than 0.10 days/m<sup>2</sup> to 0.15 days/m<sup>2</sup> are achieved.

On the other hand, in a confined masonry building process the time requirements/m<sup>2</sup> are higher, so in unit time 2.04 days/m<sup>2</sup> have been found to 2.24 days/m<sup>2</sup> , in adjusted time it has been found from 2.04 days/m<sup>2</sup> to 2.26 days/m<sup>2</sup> .

In the relationship between execution time and building surfaces for times adjusted by Gantt, for VUF, there is a polynomial trend of y = 0.0003x2 + 0.0876x + 2.004 and (R<sup>2</sup> = 0.9072) this trend is low in comparison to the VAC trend. For VAC, there is a polynomial trend of y = 0.0075x2 + 1.8927x – 10.777 (R<sup>2</sup> = 0.9879), this trend is very high compared to the VUF trend (**Figure 14**).

The trend of the construction processes of houses with confined masonry requires a longer time than for the processes of building houses with premanufactured elements. The VAC, the greater the construction area, the longer time is required for the building, whereas the VUF the building process in the

**Figure 14.** *Projected trend lines time/surface ratio of VUF and VAC.*

surface variable there are no significant differences, this item is more dependent on the production capacity of machines and equipment.
