dreng_dlg.dcl — Rebar Engineering Calculations

File: dreng_dlg.dcl
Version: v3.60
Category: Dialog Definitions
Size: 6.4 KB (195 lines)

Note

Rebar Engineering Module

Performs reinforcement engineering calculations including flexural capacity, shear capacity, development lengths, and bar spacing verification per ACI 318 requirements.

Functional Purpose

Rebar Engineering Calculations - Automated engineering analysis tool that calculates reinforcement requirements, verifies capacity, checks development lengths, and ensures ACI 318 code compliance.

Key Functions:

  1. Calculates flexural capacity (moment strength)

  2. Verifies shear capacity (diagonal tension)

  3. Determines development lengths (bar anchorage)

  4. Checks bar spacing (code minimums and maximums)

  5. Computes crack control (bar spacing for serviceability)

  6. Generates rebar schedules (bar lists, bending diagrams)

User Need

Engineering calculations for:

  • Design verification (confirm panel reinforcement adequate)

  • Code compliance (ACI 318 requirements)

  • Optimization (minimum rebar for capacity)

  • Quick checks (preliminary design, concept review)

  • Documentation (calculation backup for submittals)

Typical Workflow

1. User has configured panel with reinforcement
2. User wants to verify capacity
3. User opens dreng_dlg (from tools or mp_dlg)
4. Dialog displays current panel data:
   • Panel: 12'×10'×6" wall
   • Rebar: #5 @ 12" o.c. vertical, #4 @ 18" o.c. horizontal
   • Concrete: f'c = 5000 PSI
   • Steel: fy = 60,000 PSI
5. User selects calculation type: Flexural Capacity
6. User enters load case: Wind lateral 30 PSF
7. System calculates:
   • Applied moment: M = wL²/8 = 15 kip-ft
   • Rebar area: As = 0.31 in²/ft (from #5 @ 12")
   • Capacity: ?Mn = 22 kip-ft
   • Result: 22 > 15 ? OK (Capacity ratio = 1.47)
8. Report generated with detailed calculations
9. User saves report to project documentation

Control Semantics

Calculation Type Selection

Analysis Options:

  • calc_type - Calculation dropdown:

    • Flexural capacity (moment strength)

    • Shear capacity (diagonal tension)

    • Development length (bar anchorage)

    • Deflection (serviceability)

    • Crack control (bar spacing check)

    • Bar schedule (generate rebar list)

Input Parameters

Material Properties:

  • fc - Concrete compressive strength:

    • Read from project settings OR

    • User override

  • fy - Steel yield strength:

    • Typically 60,000 PSI (Grade 60)

    • Sometimes 75,000 PSI (Grade 75)

Geometry:

  • width - Panel width (from panel data)

  • height - Panel height

  • thickness - Panel thickness

  • cover - Concrete cover to reinforcement

Reinforcement:

  • vert_bars - Vertical bar size and spacing

  • horiz_bars - Horizontal bar size and spacing

  • As - Steel area (calculated or entered)

Loads:

  • load_case - Load scenario dropdown:

    • Wind lateral

    • Seismic lateral

    • Gravity (self-weight + live)

    • Combined (factored load combinations)

  • load_value - Load magnitude (PSF, kips, etc.)

Output Display

Results Section:

  • capacity - Calculated capacity (kip-ft, kips, inches)

  • demand - Applied load/moment

  • ratio - Capacity/Demand ratio

  • status - Pass/Fail indicator (?/?)

Detailed Calculations:

  • calc_steps - Text box showing step-by-step calculations

  • code_ref - ACI 318 section references

  • warnings - Any code violations or concerns

Engineering Calculations

Flexural Capacity

Calculation Method (ACI 318):

Given:
Panel: 12' wide × 10' tall × 6" thick
Rebar: #5 @ 12" o.c. vertical
Concrete: f'c = 5000 PSI
Steel: fy = 60,000 PSI
Cover: 3/4" each face

Step 1: Effective depth
d = t - cover - db/2
d = 6" - 0.75" - 0.625"/2 = 4.94" ? 5"

Step 2: Steel area per foot width
As = (Bar area) / (Spacing)
As = 0.31 in² / 12" = 0.0258 in²/in = 0.31 in²/ft

Step 3: Reinforcement ratio
? = As / (b × d)
? = 0.31 / (12 × 5) = 0.0052 = 0.52%

Check: ?min = 0.0018 (ACI 14.3.2)
0.52% > 0.18% ? OK

Step 4: Neutral axis depth
a = (As × fy) / (0.85 × f'c × b)
a = (0.31 × 60,000) / (0.85 × 5000 × 12) = 0.37"

Step 5: Nominal moment capacity
Mn = As × fy × (d - a/2)
Mn = 0.31 × 60,000 × (5 - 0.37/2) / 12,000
Mn = 7.5 kip-ft per foot width

Step 6: Design capacity
? = 0.9 (tension-controlled)
?Mn = 0.9 × 7.5 = 6.75 kip-ft/ft

For 12' wide panel:
?Mn = 6.75 × 12 = 81 kip-ft total

Shear Capacity

Calculation Method:

Given same panel:

Step 1: Concrete shear capacity
Vc = 2 × ? × ?f'c × bw × d
? = 1.0 (normal weight concrete)
Vc = 2 × 1.0 × ?5000 × 12 × 5
Vc = 8,485 lbs ? 8.5 kips per foot width

Step 2: Design shear capacity
? = 0.75 (shear)
?Vc = 0.75 × 8.5 = 6.4 kips/ft

For 12' wide panel:
?Vc = 6.4 × 12 = 76.8 kips total

Check against applied shear:
Wind: 30 PSF × 10' × 12' / 2 = 1.8 kips
76.8 > 1.8 ? OK (huge safety factor)

Development Length

Calculation Method:

Development length for #5 bar:

ld = (3/40) × (fy/??f'c) × ?t × ?e × ?s × db

Where:
fy = 60,000 PSI
f'c = 5000 PSI
? = 1.0 (normal weight)
?t = 1.0 (top bar factor, assume not top)
?e = 1.0 (epoxy factor, assume uncoated)
?s = 1.0 (bar size factor)
db = 0.625" (#5 bar diameter)

ld = (3/40) × (60,000/(1.0×?5000)) × 1.0 × 1.0 × 1.0 × 0.625
ld = 0.075 × (60,000/70.7) × 0.625
ld = 39.8" ? 40"

Or: ld = 12" minimum (ACI)

Use: 40" development length for #5 bars

Integration

Called By:

  • Tools menu ? Rebar Engineering

  • mp_dlg ? Engineering check button

  • Right-click on panel ? Verify Capacity

Calls:

  • Panel data retrieval functions

  • Material property database

  • ACI code calculation library

  • Report generation module

Variables:

  • Reads: All panel geometry and reinforcement data

  • Writes: Calculation results, capacity ratios

  • Outputs: Engineering report (text or PDF)

User Example

Scenario: Verify if 10’ tall wall can resist 40 PSF wind

1. Panel configured: 12'×10'×6", #5 @ 12" vertical
2. User opens dreng_dlg
3. Select: Flexural Capacity check
4. Load case: Wind lateral 40 PSF
5. System calculates:
   • Applied moment = 40×10²/8 = 50 kip-ft
   • Panel capacity = 81 kip-ft
   • Ratio = 81/50 = 1.62 ? OK
6. Report: "Panel adequate for 40 PSF wind. SF=1.62"
7. User saves report to project folder

Best Practices

When to Use:

  • ? Preliminary design (quick capacity check)

  • ? Design optimization (try different bar sizes)

  • ? Code verification (before submission)

  • ? Troubleshooting (panel failing, need more rebar?)

Limitations:

  • ?? Simplified calculations (not full finite element)

  • ?? Standard load cases only (custom loads need engineer)

  • ?? Does not replace structural engineer review

  • ?? For critical structures, full analysis required

Validation:

  • ? Always have structural engineer verify results

  • ? Use for guidance, not final design authority

  • ? Check against hand calculations for critical panels

  • ? Document assumptions in reports

Documentation Metadata

Enhancement Status: ? COMPREHENSIVE - ENHANCED [2/23 v3.60 remaining]

End of Document