Cuplock – Base Jack

(Adjustable Base) – EN74 / BS1139

Product Overview

‌Cuplock Base Jack, or commonly known as the Adjustable Base, is the unit that builds the foundation of the entire ALTRAD SPAR scaffolding and shoring systems. Its primary function is to locally reinforce the floor under vertical loads from the ground while allowing a slight adjustment to accommodate uneven ground or an uneven surface. An Base Jack consists of a solid or hollow threaded spindle, a forged nut, and a base plate welded to the bottom to ensure stability. The device is made from high-strength steel and hot-dip galvanized to resist rust, providing a safe, level, and rigid support for Cuplock standards in challenging site conditions. The assembled component is the product of design and testing procedures that lead to conformity with Aramco GI 8.001, SABIC §9.4, BS EN 74, and BS EN 12811 local and international rules regarding structure and safety.

Key Features & Advantages

  • Precision Adjustment: Provides ±300 mm vertical fine leveling capability.
  • High Load Bearing: Each base jack supports up to 45 kN SWL.
  • Corrosion Protection: Fully hot-dip galvanized to ISO 1461 with ≥ 85 µm coating
  • Thread Accuracy: Machined threads ensure smooth adjustment under load.
  • Universal Fit: Compatible with, and other modular systems..
  • Safety & Stability: Large base plate (150 × 150 mm) ensures even load distribution and minimizes ground penetration.

Technical Specifications

  • Material: Carbon Steel Grade S355 (EN 10025)
  • Thread Type: ACME / Trapezoidal rolled thread
  • Welding: CO₂ / MIG per ISO 3834-2
  • Finish: Hot-Dip Galvanized (ISO 1461)
  • Adjustment Range: 300 mm (standard), custom ranges available

Dimensional Data

Item Code Description Spindle OD (mm) Thread Length (mm) Plate Size (mm) Plate Thickness (mm) Weight (kg)
SP-BJ-0450 Base Jack 450 mm 36 350 150 × 150 6 3.8
SP-BJ-0600 Base Jack 600 mm 36 450 150 × 150 6 4.3
SP-BJ-0750 Base Jack 750 mm 36 600 150 × 150 6 4.9
SP-BJ-0900 Base Jack 900 mm 36 750 150 × 150 8 5.6

Load Capacity & Structural Performance

Parameter Unit Value Standard Reference
Safe Working Load (SWL) kN 45 BS EN 12811 Annex D
Ultimate Load kN 67 BS EN 12811
Adjustment Range mm 300–750 Design Spec
Thread Type – Rolled ACME Internal Spec
Base Plate Bending Strength kN·m 5.8 Internal Test Certificate SPAR-QA-2024
Safety Factor – 1.5 Aramco GI 8.001
Surface Coating µm ≥ 85 ISO 1461

All tests have been confirmed by ALTRAD SPAR QA Laboratory Load Test Certificates. Validation was performed using hydraulic frame testing in accordance with BS EN 12811. The entire process was independently verified and approved by third-party inspectors (TÜV / Intertek).

Compliance Standards

Reference Requirement
Aramco GI 8.001 Section 5.3: Scaffold base support and foundation requirements.
SABIC §9.4 Section 7.2: Inspection and revalidation intervals for scaffold components.
BS EN 74 Clause 5: Coupler and base jack mechanical performance.
BS EN 12811 Annex D: Load testing of temporary works components.
ISO 1461 Clause 6: Galvanizing thickness and adhesion tests.
ISO 3834-2 Clause 8: Welding quality and inspection control.

Quality Assurance & Testing

Inspection Process

  • Raw material verification with MTC traceability (EN 10219).
  • Machining inspection (thread pitch, depth, and alignment).
  • Galvanizing coating test using magnetic gauge (≥ 85 µm).
  • Proof load testing (axial compression) per BS EN 12811.
  • Dimensional check using calibrated jigs.
  • Final marking, stamping, and documentation per ALTRAD SPARQA SOP 12.3.

QA/QC Verification Summary

Inspection Stage Method Acceptance Criteria Frequency
Material Verification MTC Review S355 / EN 10219 Each batch
Thread Inspection Pitch Gauge ±0.5 mm tolerance 100%
Plate Weld Visual + MT No visible cracks 10% sample
Galvanizing Coating Gauge ≥ 85 µm Each lot
Load Test Hydraulic Frame ≥ 45 kN SWL Quarterly
Marking Visual Batch + Heat No. 100%

Identification & Traceability

Every Base Jack is permanently marked with::

  • “ALTRAD SPAR– BASE JACK – [Length] – [Batch No.] – [Heat No.] – [Year].”
  • QA inspector stamp and load rating..
  • Optional QR/barcode for ERP traceability.

Applications

  • Shoring and formwork systems
  • Tank and vessel scaffolding bases
  • Pipe-rack and equipment access platforms
  • Industrial and infrastructure scaffolds
  • Offshore platform support scaffolds

Maintenance & Inspection

Item Frequency Method
Visual inspection Before each use Check threads, welds, and plate integrity
Thread lubrication Monthly Apply anti-seize lubricant
Coating verification Every 3 years Check galvanizing ≥ 85 µm
Proof load retest Every 5 years Verify ≥ 45 kN load capacity

Marking & Identification

Each Ledger is permanently stamped with:

  • “ALTRAD SPAR– LEDGER – [Length] – [Batch No.] – [Heat No.] – [Year]”
  • QA inspection mark and batch traceability reference.
  • Optionally available with QR/barcode labels for asset tracking in ERP systems.

Typical Applications

  • Industrial access scaffolds
  • Tank and vessel scaffolding
  • Bridge decks and suspended platforms
  • Formwork, bracing, and shoring grids
  • Maintenance structures in refineries and petrochemical plants

Maintenance & Inspection Guidelines

Item Frequency Method
Visual inspection before issue Every hire cycle Check blade ends, tube dents, and corrosion
Dimensional recheck Annual Verify length and blade seating
Proof load retest Every 5 years Hydraulic load validation as per BS EN 12811