Welcome back to our comprehensive Revit Structure series. Now that we've successfully positioned our earthquake-resisting frame beams, we'll tackle the critical next phase: implementing our vertically-loaded beams and girders to complete the structural framework.
We'll begin with our primary girder placement using a W21×44 section. Navigate to Structure > Beam, then access the Type Selector dropdown to locate and select the W21×44 profile. This section provides an optimal balance of structural capacity and material efficiency for our application.
With the girder selected, we'll strategically place the W21×44 members along this designated alignment. These girders serve a dual function as drag members for our moment frame system, effectively transferring lateral loads along their span directly into the primary structural frame—a critical component for seismic resistance.
Continue this placement pattern on the opposite side to maintain structural symmetry and load distribution. This systematic approach ensures consistent load paths throughout the structure.
Note that these girders are positioned at Level 2 with a precise vertical offset of -5½ inches from the finished floor elevation. This offset accounts for our 5½-inch-deep floor system, ensuring proper integration between structural and architectural elements while maintaining the required headroom clearances.
Next, we'll address the interior girder placement using W21×50 sections. Access the Type Selector again and choose the W21×50 profile for this phase. The increased section weight is structurally justified—these interior members support significantly greater tributary loads from both sides, compared to exterior girders that only carry loads from one direction.
Begin systematic placement of these heavier sections, working methodically around existing beam locations. This careful coordination prevents conflicts while ensuring structural continuity. Position members along each designated gridline, maintaining consistent spacing and alignment.
Place the girder at this location, then proceed systematically along this primary line. Continue this pattern along the final gridline to complete the girder system. With this foundation in place, we're ready to install the secondary beam network that will support our distributed loading systems.
Our beam placement will utilize a strategic combination of W21×44 and W18×35 sections, selected based on specific loading conditions and span requirements. First, locate the W21×44 in the Type Selector and verify the placement parameters.
These beams are also positioned at Level 2, but since they won't support additional framing members, they function essentially as heavy joists in our system. Confirm the vertical offset remains at -5½ inches from finished floor to maintain consistency with our floor system integration.
Begin placement at this starting point and work systematically through the model. Position beams at these locations, ensuring proper alignment with the established grid system. This methodical approach prevents gaps in coverage while maintaining structural efficiency.
For our interior beam lines, we'll transition to W18×35 sections, which provide adequate capacity for the reduced loading conditions in these locations. Locate and select this profile from the Type Selector, then verify all parameters before proceeding.
With the lighter section selected, begin placement along the interior grid lines. Start at this position, and when encountering existing beam locations, work around them while maintaining the overall structural pattern.
This represents a complete beam line, so place members across its entire length. The software intelligently defaults placement to column midpoints, which aligns perfectly with our structural design intent. Follow the grid line systematically to ensure complete coverage.
Position beams at these three locations to complete the primary grid. With our main beam system established, we must now address the structural framing around building openings—a critical aspect often overlooked in initial planning.
This opening accommodates a vertical shaft and requires careful framing consideration. We'll place a W18×35 here to initiate the opening frame, then span across the opening using a lighter W14×22 section—appropriate for the reduced loads in this area.
To access this beam size, go to Edit Type, then click Load to access the structural library. This process allows us to import additional section sizes as needed throughout the design process.
Navigate to Structural Framing > Steel > W Shape to open the comprehensive section database. Scroll through the available options to locate the 14-inch-deep sections, then select the W14×22 profile and confirm with OK.
Return to the Type Selector and choose the newly loaded W14×22 section. Click OK to activate this beam type, then place the member across the stair opening, spanning from the established beam on one side to the corresponding beam on the opposite side.
With the stair properly framed, we'll address the elevator shaft using similar principles. Place a W18×35 across the elevator front, spanning from one side of the opening to the other to provide adequate support for the elevator loads.
The elevator shaft itself requires additional framing using our W14×22 members. Access the dropdown menu and place one beam spanning from this location to that beam, then add a second member from this beam to that corresponding beam. This creates a complete frame around the elevator opening.
Step back to review our completed work. Exit the current command and zoom out to appreciate the full scope of our structural system. We've successfully implemented comprehensive framing for stairs, elevator systems, interior structural grids, and exterior framing elements—creating a robust foundation ready for the beam system installation we'll cover in our next tutorial.
This completes our beam and girder placement phase. Join us in the next video where we'll dive into the beam system installation process that will tie this entire structural framework together.