Dagny Carlsson

Journal Entry For
Module 8B - Structural Analysis Test Cases
BIM360 Folder Link

For my structure, I chose steel elements due to their ability to support greater loads with fewer supports. I did not want to compromise the flexibility of my space due to a change in structural material, and decided to target my sustainability goals elsewhere.

Case 1: Truss for Exhibition Hall


The truss length is 60.5' and is 4' tall. This truss spans my largest exhibition room and prevents me from having to use lots of columns, disrupting the space. I think I was quite conservative with the span of this truss, and it may even be possible to reduce it in size, which would be preferable for this space and allow me to direct more space towards HVAC. I included a live load of .05 ksf because this beam supports a crowded open office space, which might at points be open as a multi-purpose space.

UPDATE: After checking in Robot, I realized the program considers each bar in the truss as a separate entity, including both beams. As a result, I received that the top bar efficiency ratio is 6.16, and the bottom beam was given as 18.79. I will have to do more searching to determine whether Trusses are good to check in Robot, or if this is legitimate instability.

Case 2: Curving Corner of Exhibition Hall


The truss spans 37.5' and is 4' tall. I chose this as an example due to the curving wall and floor cantilever due to my curving design for the building exterior. I am rather confident that the truss will be able to adequately support the load, particularly because it is close to other beams that are meant to support this region of floor. I included a load of .05 ksf because this is also supporting the open office, multi-purpose space.

UPDATE: The beams in the curved part have efficiency ratios at .26 and .12 respectively, indicating this cantilevered portion will be secure, even if the load is significantly increased. I will likely have plenty of room for HVAC in this area. The beam between the truss and the curved area has a RAT of .89, which is quite good. No further concern for this area.

Case 3: Cantilevered Terrace Area


Under study is this exterior cantilevered beam system that supports the exterior terrace. The span is approximately 64.5'. I am less confident in the support system here, but it is designed to support significantly less weight: only .03 ksf. This is because there will be a live load of fluctuating student population, meaning that the beam here is not bearing nearly as much weight as the rest of the building. Here it is less significant if the support needs to be strengthened because there will be no HVAC elements on the exterior of the building, meaning that support here can be fully prioritized (as it should be).

UPDATE: According to Revit, the beam supporting the terrace is unstable and has a RAT of 2.23, meaning it may need to be strengthened. This is not a giant issue, as previously stated I explained that this is external and wouldn't affect HVAC. It can be reinforced easily with few repercussions.