lb_dlg.dcl — Ledger Beam Connection Configuration¶

File: lb_dlg.dcl
Version: v3.60
Category: Dialog Definitions
Size: 9.1 KB (268 lines)

Note

Beam Support Feature

Configure ledger beam connections for roof/floor systems supported by precast panels. Critical for proper beam bearing and load transfer.

Functional Purpose¶

What This Dialog Does¶

Ledger Beam Connections - Configures connection points where structural beams (steel or wood) attach to panel face for roof or floor framing support.

Key Functions:

Positions beam connection points (up to 32 positions)
Specifies connection types (pocket, seat, embed plate, bolt)
Sets beam sizes (W8, W10, W12, wood dimensions)
Defines bearing details (width, depth, elevation)
Controls face orientation (which panel face beam bears on)

User Need¶

Roof/Floor Framing Support

Users configure ledger connections for:

Roof beam attachment (steel beams bearing on wall panels)
Floor joist support (wood or steel joists at each floor level)
Deck ledgers (roof deck or floor deck framing)
Structural frame connections (panel acts as bearing wall)
Mezzanine support (intermediate floor framing)

Typical Workflow¶

User in mp_dlg clicks [Ledger Beam]
lb_dlg opens
User enables connection (lbt1)
User selects type: "Beam pocket" (recess in concrete)
User specifies beam: W10×26 (10" deep steel beam)
User sets position: 10'-0" from left edge
User sets elevation: 7'-6" (near top of panel for roof beam)
User sets bearing width: 6" (beam flange width)
User clicks OK
Beam pocket symbol drawn on panel

Control Semantics¶

Per-Connection Controls (32 max)¶

Connection 1 Example:

lbt1 - Enable toggle
lbx1 - Connection type dropdown:
- Beam pocket (recess cast into panel) - Most common
- Beam seat (L-shaped bearing plate)
- Embed plate (steel plate cast flush)
- Bolted connection (through-bolts to panel)
- Welded connection (weld to embed plates)
lbq1 - Face/edge selection:
- L = Left edge
- R = Right edge
- T = Top edge (parapet bearing)
- F = Front face
- B = Back face
lbd1 - Distance from panel corner
lbe1 - Elevation from finished floor
lbw1 - Connection width (beam flange width or pocket width)
lbc1 - Connection capacity/size:
- Light (< 5 kips)
- Medium (5-15 kips) - Most common
- Heavy (15-30 kips)
- Extra Heavy (> 30 kips)
lbh1 - Connection height/depth (pocket depth, seat height)

Connection Types Explained¶

Beam Pocket¶

Most Common - Recess cast into panel edge:

Beam slides into pocket during erection
Concrete surrounds 3 sides of beam
Provides fire protection
Typical depth: 4”-8” into panel
Typical width: Beam flange + 1”

Advantages: ? Fire protection for beam ? Clean appearance (beam hidden) ? Positive bearing (can’t slide off)

Disadvantages: ? Must be accurate (can’t adjust after casting) ? Complex forming ? Reduces effective panel width

Beam Seat¶

L-shaped steel angle cast into panel:

Beam rests on horizontal leg
Vertical leg anchored to panel
Easier field adjustment
Typical: L4×4×1/2” or L6×6×1/2”

Advantages: ? Field-adjustable (shim for elevation) ? Simpler forming ? Can bolt beam for positive connection

Embed Plate¶

Steel plate cast flush with panel surface:

Beam welds or bolts to plate
Very strong connection
Can resist moment (welded)
Typical: 6”×8”×1/2” plate

Engineering Considerations¶

Load Calculations¶

Beam Reactions Must Be Known:

Tributary Area Method:
Beam Spacing: 20 ft
Roof Load: 40 psf (dead + live)
Beam Span: 30 ft

Reaction = (20 × 30 × 40) / 2 = 12,000 lbs = 12 kips

Required Bearing:
Assuming 0.85f'c concrete (f'c = 5000 psi):
Bearing stress = 0.85 × 5000 = 4,250 psi
Required Area = 12,000 / 4,250 = 2.82 sq in
Minimum Width = 3" (for 6" deep pocket)

Use: 6" wide × 6" deep pocket (safe)

Pocket Dimensions¶

Width: Beam flange + clearance

W10 beam flange: 5.8” ? Use 6-7” pocket width
W12 beam flange: 6.5” ? Use 7-8” pocket width

Depth: Minimize for panel strength

Minimum: 4” (light loads)
Standard: 6” (typical)
Maximum: 8” (avoid weakening panel edge)

Bearing Length: Along beam span

Minimum: 3” (ACI requirement)
Standard: 4-6”
Longer bearing = lower bearing stress

User Example¶

Scenario: Roof beams every 20 ft, 5 beams total

1. User: Opens lb_dlg
2. Configure Beam 1 (left end):
   • lbt1: Enable
   • Type: Beam pocket
   • Face: Top edge (T)
   • Distance: 2'-0" from left
   • Elevation: 7'-6"
   • Width: 7" (for W10 beam)
   • Depth: 6"
   • Capacity: Medium (12 kips)

3. Configure Beams 2-5:
   • Spacing: 20'-0" on center
   • Same pocket dimensions
   • lbt2: 22'-0" from left
   • lbt3: 42'-0" from left
   • lbt4: 62'-0" from left
   • lbt5: 82'-0" from left

4. User clicks OK
5. Result: 5 beam pocket symbols drawn at panel top

Integration¶

Called By: mp_dlg ? [Ledger Beam] (mplb)
Drawing: Beam connection symbols with dimensions and callouts

Variables:

lbt1-lbt32 - Enable flags
lbx1-lbx32 - Connection type
lbq1-lbq32 - Face/edge
lbd1-lbd32 - Position
lbe1-lbe32 - Elevation
lbw1-lbw32 - Width
lbc1-lbc32 - Capacity
lbh1-lbh32 - Height/depth

Best Practices¶

Pocket Placement¶

Avoid:

? Too close to panel edge (< 6” from corner)
? Too deep into panel (> 8” weakens edge)
? Interference with rebar/welds
? Misalignment with beam layout

Best:

? Minimum 6” from corners
? 4-6” pocket depth (standard)
? Coordinate with structural drawings
? Verify beam size before casting

Common Applications¶

Roof Beams:

Spacing: 15’-25’ on center
Loads: 10-20 kips typical
Connection: Beam pocket (fire protection)

Floor Joists:

Spacing: 16”-24” on center (wood) or 4’-8’ (steel)
Loads: 5-15 kips per joist
Connection: Joist hangers or seats

Mezzanine:

Spacing: 10’-15’ on center
Loads: 15-30 kips
Connection: Heavy-duty seat or welded plate

Documentation Metadata¶

Enhancement Status: ? COMPREHENSIVE - RECREATED [4/13]

End of Document