For my building I decided to go with a reinforced concrete structure. Since this building will be located in Guayaquil, Ecuador, one important factor was the labor and materials cost that concrete offer. Concrete is the most common type of structure frame in Guayaquil because of its lower cost and thermal conductivity.
Another reason why I decided to go with concrete is because of the visibility of its structural elements. Most of the columns can be hidden within the walls, giving wider spaces without compromising the architectural design. The idea behind this building is to highlight these eye catching spaces.
One major challenge was placing the grids. Every floor has a different layout so I tried placing them in a "common ground" for all the levels. Afterwards I placed grids where I needed in every floor to make it easier to place columns. The columns were placed based on the rooms and walls of the building; they were hidden with walls or placed to separate rooms as much as possible without surpassing a 9 m span to aviod bigger beams. However, the height of 5 m between levels is sufficient to allow HVCA systems and beams to go through without any incident between them.
For the 1st level I went for a 30x45 cm columns considering some spans of 7-8 m (25 ft approximately). I designed the beams for 30 x 75 cm in the perimeters and the rest vary depending on the span. As a pre dimensioning I took 1/10 or 1/12 of the span between columns for the height, and 1/2 or 1/3 of the beam's height for the width. The same rule was applied for the rest of the levels, with the exception of the columns.; the lower levels need bigger columns, so their dimensions lower while they go up.
Level 2 has columns of 30 x 40 cm.
Level 3 has columns of 20 x 40. This level carries less weight overall since it only supports the roof of the lobby with its mechanical room for the elevators on top.
Moreover, I decided to create some bearing walls for the core spaces like the elevator. I framed the front of the openings with beams while the back and sides are supported by these bearing walls.
I decided to go with a lightweight slab of concrete of 6 cm, supported by a system of joists of 21 height (15 cm under slab) by 9 of width separated by an uniform distance of 60 cm.
I still have to define the structure for the bridge floor between the blocks. Since it has a great span and width, I'm between using trusses or keep the lightweight concrete floor supported by beams and joists.