For the structural skeleton, I used my exterior walls as structural walls. This works really well on the 2 smaller buildings, as they can be supported with one beam in the middle to support the full span, with each being about 25 feet long. Beams used here are W 14x30, and columns are W 12x40, as these should support the foot-traffic loads anticipated, as well as the snow and wind loads for the area.
The roof on the main building is a bit more complicated, as it is slanted to accommodate the PV array and has a massive skylight in the middle with others dispersed about. To support this roof, I kept the columns about 25 ft apart and kept the cross beams on a constant slope to match the roof slope.
I am using thick structural flooring for optimal heat retention and structural strength, as well as footings below the walls and each column, whether it be in the building or under the patio.
Some interior views of the coordination: Exhibit 3 (top), Main Entrance (middle), Second floor hallway overlook (bottom)
This week, I also finalized some things before I jumped into the structural system. I updated the roof to be a proper material, not generic, and it turns out to have better heat attributes than before, which is ideal because this area has a high heating need half the year. The roof I am using is a Steel Truss with Insulation on Metal Deck – EPDM, almost 2 ft thick with Thermal Resistance (R) of 113.1719. This is used under the green roof (or “floor”) with a gap for proper modeling on the second floor section and the extension buildings on the third floor level. It comes with a parapet wall on Level 3 only because of the height of the drop, while I omitted the parapet on Level 2 because it is only 1 story high and I would like to maximize the amount of light on the grass and also make sure it is visible through the curtain walls and patio on the second floor of the building. The green roof is about 57% of the total footprint, which is above my minimum goal of 50% but below my ideal mark of 70%. I will have to settle for this figure, as I want to make sure the building is easily constructible and want to keep the PV system on the taller, main building (biggest building, most north) roof. With the footprint of the main building and my note on constructability, I could not break up the main roof for partial “green roofing.” Between the green roof and the main building roof, there is also a door and ladder for easy maintenance and upkeep of the green roofs and the PV system. I slanted the roof on the main building for an increased efficiency PV system year round, as the angle of the sun will be lower and the efficiency of PV arrays drops with more shadows cast upon them. I moved them around the skylights, as it is important for me to maintain daylighting throughout. These solar panels will have adjustable angles to maximize their acceptance angle to the sun as the seasons change. The array was also kept on the main building because the large storage/mechanical room is on the second floor of this building, so it will be easier to keep all the equipment in one place. Inside, I updated the internal circulation to reflect how I plan on having people, light, and air to move throughout the space. I updated the walls for the café seating to be curtain walls for daylighting, as well as added doors for those rooms, and made sure the hallway overlooking the lobby had an unconnected height to allow an open, connected feel and more light to travel through from south to north. I also finalized the windows on the north side of the building to be smaller, to allow heat from sunlight to stay trapped in the buildings more easily.