Reinforced Concrete Foundation
Power Pack Drive Assembly — Conveyor 8A-CV-7
Moatize Mine, Tete Province, Mozambique
| Client | Vulcan Mozambique S.A. |
| Contractor | M&F Trading Lda. |
| Project | Replacement of 8A-CV-7 Conveyor Gearbox with SEW Solution |
| Document | Structural Calculation Memoir and Specification |
| Revision | Rev 1 — Corrected Load Assumptions |
| Date | 10 February 2026 |
Equipment Summary
This foundation supports the SEW Power Pack drive assembly for Conveyor 8A-CV-7. The drive consists of a 400 kW AC motor, bevel-helical gear unit, fluid coupling, low-speed coupling, and a fixed steel skid base — with a combined total weight of 6,500 kg.
| Component | Model | Key Parameter |
|---|---|---|
| Motor | SEW DRN355LMR4 | 400 kW, 1492 rpm, IE3 |
| Gearbox | SEW X3KS190e/HU/B | Output: 31,545 Nm (design value) |
| HSS Coupling | KWD 630TK | Fluid coupling (torque-limiting) |
| LSS Coupling | Vulkan GBND-A 500 10 | Vibration damping |
| Steel Skid Base | Custom (4,183 mm) | Fixed mounting platform |
ℹ️ Design Note: The gearbox output torque of 31,545 Nm represents the most conservative value across all source documents. This ensures the foundation is adequate regardless of the final gearbox ratio selected (12.57 to 15.77).
Design Parameters
⚠️ Geotechnical Note: The soil bearing capacity of 70 kPa has been assumed without geotechnical investigation. DCP tests or plate load tests must be performed at the foundation location before construction commences.
Load Analysis & Combinations
The foundation is subjected to permanent loads (self-weight + equipment), variable loads (maintenance access), and dynamic loads from the rotating machinery. A Dynamic Amplification Factor (DAF) of 2.0 is applied per ACI 351.3R for equipment operating above 600 rpm.
| Load Type | Description | Value |
|---|---|---|
| Foundation Self-Weight | 5.0 × 2.0 × 0.6 × 25 kN/m³ | 150.0 kN |
| Equipment (Static) | 6,500 kg × 9.81 m/s² | 63.8 kN |
| Equipment (Dynamic) | 63.8 × DAF 2.0 | 127.5 kN |
| Live / Maintenance | 3.0 kN/m² × 10.0 m² | 30.0 kN |
| Torsional Reaction | 31,545 Nm × 1.5 (transient) | 47.3 kNm |
Load Combinations (RSAEEP / REBAP)
| Combination | Limit State | Value | Governs |
|---|---|---|---|
| LC1: Static | ULS | 333.6 kN | — |
| LC2: Dynamic | ULS | 419.7 kN | Governs |
| LC3: Dynamic + Torsion | ULS | 419.7 kN + 71.0 kNm | — |
| SLS Dynamic | SLS | 307.5 kN | Governs (Bearing) |
✅ Structural Verification Results
All structural verifications pass with comfortable safety margins. The foundation is governed by minimum reinforcement requirements rather than applied loads, confirming the design is robust.
| Verification | Applied | Capacity | Utilization | Result |
|---|---|---|---|---|
| Bearing Capacity | 36.4 kPa | 70 kPa | 52% | ✓ Pass |
| Mass Ratio | 2.31 | ≥ 2.0 | — | ✓ Pass |
| Frequency (Motor) | r = 1.62 | > 1.5 (over-tuned) | — | ✓ Pass |
| Frequency (Gearbox) | r = 0.10 | < 0.5 (under-tuned) | — | ✓ Pass |
| Min. Reinforcement | 904.8 mm²/m | 899.1 mm²/m | 100.6% | ✓ Pass |
| Bending (Worst) | 3.36 kNm/m | 159.1 kNm/m | 2.1% | ✓ Pass |
| Shear | 8.69 kN/m | 190.7 kN/m | 4.6% | ✓ Pass |
| Crack Width | 0.008 mm | 0.3 mm | 2.7% | ✓ Pass |
| Anchor Bolt (Tension) | 7.89 kN | 150 kN | 5.3% | ✓ Pass |
| Total Settlement | 6.8 mm | 25 mm | 27% | ✓ Pass |
| Differential Settlement | 3.4 mm | 10 mm | 34% | ✓ Pass |
🔩 Anchor Bolt Design
The steel skid base is fixed to the concrete foundation via 12 No. M36 Class 8.8 chemical anchors (Fischer FIS EM Plus resin system) with 300 mm embedment depth. The anchors are arranged in 2 rows of 6, spaced approximately 1.5 m apart.
| Parameter | Value |
|---|---|
| Anchor Type | Fischer FIS EM Plus (Chemical) |
| Rod | M36, Class 8.8 |
| Quantity | 12 (2 rows × 6) |
| Embedment (hef) | 300 mm |
| Tension per Bolt | 7.89 kN (Utilization: 5.3%) |
| Shear per Bolt | 0 kN (Resisted by friction) |
| Edge Distance | 375 mm > cmin ≈ 150 mm ✓ OK |
📋 Installation Requirements: Drill holes and install anchors only after concrete reaches 28-day strength. Follow Fischer's cleaning protocol: 2× brush + 2× blow. Allow full cure time before applying load.
Outstanding Actions Before Construction
1. Perform DCP tests at foundation location (min. 3 points) to verify soil bearing ≥ 70 kPa
2. Specify non-shrink grout type (cementitious or epoxy), min. 25 mm thick
3. Re-check motor-gearbox alignment at 7 and 28 days after loading
Construction Specifications
Concrete
C25/30.XC2(P).Cl 0,4
Min. cement: 300 kg/m³
Max w/c ratio: 0.55
Slump: S3 (100–150 mm)
Reinforcement
A400NR steel
ø12 @ 125 mm c/c
Both directions, top & bottom
Lap length: min. 600 mm
Subgrade
Excavate 1.2 m depth
200 mm rockfill sub-base
400 mm compacted fill
90% Mod. AASHTO density
Testing
9× concrete cubes (150³ mm)
3 sets: 7, 14, 28 days
Independent lab approved
Compaction density per layer
Anchors
Fischer FIS EM Plus
M36, Class 8.8 rod
hef = 300 mm
Install after 28-day cure
Grouting
Non-shrink cementitious grout
Min. 25 mm / Max. 50 mm
Surface roughened (bush-hammer)
Before final bolt tensioning
📋 Bill of Quantities
The following quantities are net measured. The Contractor shall allow for wastage in their unit rates. All items include labour, materials, equipment, and incidentals required for proper execution.
| Art. | Description | Unit | Qty |
|---|---|---|---|
| 1.1 | Excavation in earth (1.2 m depth) | m³ | 18.5 |
| 2.1 | Rockfill sub-base (200 mm layer) | m³ | 3.1 |
| 2.2 | Selected fill (400 mm, compacted in 200 mm layers) | m³ | 6.2 |
| 3.1 | Compaction to 90% Mod. AASHTO | m² | 15.4 |
| 4.1 | Concrete C25/30 slab (5.0 × 2.0 × 0.6 m) | m³ | 6.0 |
| 5.1 | Formwork (perimeter) | m² | 8.4 |
| 6.1 | A400NR reinforcement (ø12 @ 125 T&B, incl. laps) | kg | 431 |
| 7.1 | Concrete test cubes (150³ mm, independent lab) | un | 9 |
| 8.1 | M36 chemical anchors (Fischer FIS EM Plus) | un | 12 |
| 9.1 | Non-shrink grout (baseplate, min. 25 mm) | m² | 6.7 |
| 10.1 | DCP tests + compaction density tests | un | 9 |
Ready to Build?
All structural verifications pass. The foundation design is ready for construction, pending geotechnical confirmation and BoQ pricing.
Prepared by M&F Trading Lda. for Vulcan Mozambique S.A.
Document Reference: 8ACV7-STR-CALC-R1 | February 2026
Structural Design Memoir v1 • Hub Knowledge Base
2026 © M&F Trading Lda. • Beira, Moçambique