Mixing lateral resisting systems in the same direction is typically inefficient due to their different stiffnesses (e.g., moment and braced frames in the same direction). However, having a different lateral resisting system in each orthogonal direction (e.g., moment frames in one direction and braced frames in the other orthogonal direction) can be cost-saving.
Many buildings have structural isolation joints to accommodate thermal or seismic movement. The width of the joint is driven by the flexibility of the lateral system—more flexible systems = larger isolation joints. Since moment frames are more flexible than braced frames and shear walls, their associated isolation joints will be larger.
The code allows for multiple methods for designing wood shear walls. Let's explore the two most common methods:
1) Segmented:requires more holdowns but typically results in lower walledge nailing.
2) Force transfer around openings (FTAO):allows for fewer holdowns but requires steel straps above and below openings and typically requires tighter wall edge nailing (including increased likelihood of double-sided sheathing where shear demand is high).
Did you know that some seismic-force-resisting systems require a higher level of detailing and design on a building than others? This higher level of detailing results in lower overall seismic forces. The following is a list of seismic force-resisting systems sorted by highest detailing requirements (lower building seismic force) to lowest detailing requirements (higher building forces) :
1. Special moment frames
2. Special braced frames
3. Wood or metal stud wall sheathed with plywood
4. Special concrete or masonry shear walls
5. Cross-laminated timber shear walls
6. Cantilevered columns
Revit BIM 360/ACC projects can only support one version year at a time. Once selected and uploaded, only the specific version of Revit can be accessed directly in the cloud. You do have the option to upgrade to a newer Revit version but not to any earlier Revit versions.
Approximate concrete tilt-up wall thickness:
Thickness = Height (in) / 55
The previous building code limited mass timberstructures to 85 feet tall and six stories of construction when using Type IVHT. The 2021 IBC added four new construction types, allowing mass timber to beused up to 18 stories for a total building height of up to 270 feet.
The Utah Code Amendment to the IEBC requires theseismic bracing of unreinforced masonry parapets or appendages, such ascornices, spires, towers, etc, when the roofing is removed and replaced on morethan 25% of the roof area.
The 2021 IBC no longer allows the use of fire-retardant-treated wood sheathing for 2-hour non-bearing partitions for shaft walls in Group I-2 or Group B Ambulatory Care Facilities.
The 2021 IBC now requires any attachment to fire-rated steel members to be rated at least 12 inches away from the structural member.
The IBC 2021 requires frost protection at exterior landings for all required exits with outward-swinging doors to ensure the exit door will be unobstructed.
The 2021 IBC adds the following criteria for a Risk Category 3 structure:
