Objectives

The primary objective of this tender is to procure services for the construction of a removable reinforced concrete chamber top slab and the fabrication and installation of a stainless-steel cat ladder inside the chamber at Birdswood. The work aims to facilitate future access for inspection, maintenance, and replacement of water isolation valves, ensuring safety, watertightness, and compliance with relevant standards.

Scope

The scope of work includes:

• Construction, installation, and commissioning of a 4.6 m x 4.6 m removable reinforced concrete chamber top slab with a 1.5 m x 1.5 m access opening and lockable lid.
• Preparation of a separate casting platform, reinforcement, formwork, concrete pouring, curing, and lifting of the slab into position.
• Fabrication and installation of a 316 stainless-steel cat ladder inside the chamber, including all supports, fixings, welding, grinding, cleaning, and passivation.
• Ensuring all works comply with safety standards and facilitate future removal and access to water valves.

Technical Requirements

The technical specifications for the chamber slab and ladder include:

Chamber Slab

• Overall size: 4.6 m long x 4.6 m wide
• Access opening: 1.5 m x 1.5 m with lockable lid
• Thickness: 300 mm
• Concrete: 35 MPa / 19 mm aggregate, watertight
• Reinforcement: 16 mm high tensile steel bars and welded steel mesh
• Reinforcement around access opening and lifting points integrated into the slab
• Slab to be cast separately and lifted into position without permanent bonding to chamber walls

Fabrication and Installation of Stainless Steel Cat Ladder

• Material: 316 stainless steel suitable for chamber environment
• Includes stiles, rungs, brackets, supports, fixings, and anchors
• Welding, grinding, cleaning, and passivation of welds
• Positioned to avoid interference with chamber equipment and water valves
• Designed for safe access, supporting personnel and service loads

Skills and Skills Requirements

The contractor must demonstrate:

• Proven experience in concrete construction, particularly with precast/removable slabs and watertight concrete
• Capability to fabricate and install stainless steel structures, including welding, passivation, and surface finishing
• Competence in site measurement, formwork erection, reinforcement placement, and concrete casting
• Ability to prepare detailed construction methodologies and safety plans compliant with OHS regulations
• Qualified personnel, including a Civil Engineering Technician with relevant experience in concrete works
• Compliance with safety standards, including proper lifting procedures and secure fixing of structures

Summary

This tender requires a contractor with expertise in concrete slab construction, stainless steel fabrication, and installation, capable of delivering a high-quality, safe, and compliant chamber access solution within the specified timeframe. The contractor must also adhere to safety, quality, and environmental standards, providing all necessary documentation and demonstrating relevant experience and registration.