Seaton and Grange Stormwater System Upgrade

Introduction

Incon was engaged by the City of Charles Sturt to deliver structural engineering design and certification for a major stormwater infrastructure upgrade along Trimmer Parade, Seaton and Grange. The project involved the design of reinforced concrete box culverts (RCBC) to enhance flood capacity, improve asset durability, and meet long-term infrastructure performance requirements.

Project
description

The project forms part of a broader council-led stormwater upgrade to improve drainage capacity and resilience within the Seaton and Grange catchment. Incon’s scope focused on the structural design of 2.4m x 1.2m reinforced concrete box culverts, including full documentation and independent third-party certification.

Key deliverables included:

Structural design calculations and engineering report
Preliminary and “For Construction” drawings
Reinforcement detailing for culverts and ancillary elements
Independent third-party certification by a Chartered Professional Engineer

The design was required to comply with:

AS5100 (Bridge Design)
AS1597.2 (Precast Box Culverts)
DIT Master Specifications (ST-SD-D1, RD-DK-S1)
Council-specific requirements

Challenge

This project involved several critical engineering and compliance challenges:

High-performance infrastructure requirements, including a 100-year design life and capacity to withstand traffic and construction loads
Strict regulatory compliance, requiring alignment with multiple Australian Standards and Department of Infrastructure and Transport (DIT) specifications
Integration with existing stormwater systems, requiring compatibility with existing hydraulic and structural conditions
Independent third-party certification requirements, necessitating fully auditable and verification-ready design documentation
Constructibility constraints, including staging, installation loads, and minimising disruption to surrounding infrastructure

Additionally, the design needed to address durability, handling loads, and penetration detailing without compromising structural integrity.

Solution

Incon delivered a robust and compliant engineering solution through:

Development of detailed structural design for RCBC units, optimised for strength, durability, and constructability
Execution of comprehensive structural calculations, covering dead loads, live traffic loads, installation loads, and long-term performance requirements
Integration of durability-focused design measures, including reinforcement cover, material selection, and detailing for a 100-year design life
Design of ancillary components, including joint bays, risers, and penetration reinforcement, ensuring full system functionality
Implementation of a multi-stage design process (preliminary → review → final), incorporating Council feedback efficiently
Coordination of independent third-party certification, ensuring compliance with regulatory and approval requirements
Delivery of high-quality, construction-ready documentation, aligned with Council standards and formats

Key Engineering Value Delivered

Delivered a fully compliant, certifiable structural design aligned with Council and DIT requirements
Enhanced long-term infrastructure performance through durability-focused engineering
Reduced project risk through early integration of certification and compliance requirements
Provided a constructible and efficient culvert design, supporting smooth project delivery
Strengthened Council confidence through clear documentation and structured design process

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We take pride in delivering innovative and practical solutions which adds real value to our clients and the community. We strive for better outcomes that delivers a best possible solution by employing our technical expertise. We believe the real value in good engineering is breaking down a complex problem into a simple solution which underpins our philosophy of ‘do it right – the first time’.