Articles
We have co-authored key industry guidance, including:
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HERA Report NZWC K-02:2026 Heat Based Surface Treatment Methods - COMING SOONThe Heat Based Surface Treatment Methods report provides the first comprehensive technical assessment of heat induction and laser surface treatment technologies for structural steel infrastructure. Drawing on laboratory testing, field trials, international research, and engineering evaluation, the report establishes a proposed framework for the safe adoption of these technologies through defined process controls, verification requirements, and health and safety measures. Rather than focusing solely on laser performance, the report presents a practical pathway for industry implementation by introducing validated operating windows, inspection and acceptance criteria, and quality assurance processes to support future specifications and regulatory compliance for bridge and infrastructure applications. Led by Structural Integrity Consultants, with technical oversight by the New Zealand Heavy Engineering Research Association (HERA), this research was undertaken with funding and material support from NSB Infrastructure and KiwiRail.
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HERA R4-166: Low-carbon design guide for steel and hybrid low-rise buildingsThis design guide applies HERA’s Low-Carbon Circular Design Framework to steel and steel-hybrid low-rise commercial buildings, outlining strategies for reducing carbon emissions. It includes case studies demonstrating over 50% carbon reductions through adaptable design, material choices, and disassembly planning. The guide also explores operational carbon reduction strategies for greater sustainability.
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HERA R4-133: 2025 – Aotearoa New Zealand steelwork corrosion and coatings guideThis revised guide has an overall objective to provide the necessary guidance to allow an appropriate and cost-effective coatings system for structural steelwork to be selected and then specified in a generic manner.
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HERA R4-97: Aotearoa New Zealand weathering steel guide for bridges – rev. 3This guide outlines requirement for designing, fabrication, construction, site climate condition, inspection and maintenance needs to be taken into consideration in order to achieve a durable, high strength, structural steel (weathering steel) in the unpainted condition. The design for weathering steel bridges should be undertaken in accordance to the relevant parts of AS/NZS 5100.6 however, there are several requirements (mostly related to detailing and suitability of environment relating specifically to weathering steel) that are outlined in this report also.
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Protective coatings for steel bridges: a guide for bridge and maintenance engineersThis document provides a summary of information to assist the bridge designer with the specification of a cost effective performance based corrosion protection system, taking into account future maintenance requirements, by using the net present value life cycle costing model. Guidance is also provided for the maintenance painting of existing steel bridges.
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SNZ TS 3404:2018 – Durability Requirements for Steel Structures (pdf 4.6MB)This specification provides guidance on the design of steel-concrete composite bridges, which consist of steel girders and reinforced concrete slabs on top. Two common forms are considered: multi-girder and ladder deck bridges. Guidance is given on the general considerations for the preliminary and detailed design process, in addition to guidance on the verification of structural adequacy in accordance with the NZ Transport Agency Bridge manual and relevant design and material standards. Additional guidance on cost effective design philosophy and durability design is also provided.
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Technical Guide Supports the Preliminary Design of Composite Steel BridgesA new technical guide is now available to assist with the preliminary design of economical composite steel multi-girder road bridges. Developed by experienced bridge designers from the engineering firm WSP in collaboration with BlueScope, the Technical Guide: Composite Steel Road Bridges aligns with current Australian standards and provides guidance for early-stage planning and design.
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Updated HERA Guide Supports Application of REDCOR® Weathering Steel in Bridge ProjectsThis 2025 edition is a comprehensive update of the original 2017 guide, bringing together applied knowledge and new industry practices to support the design of economical bridges made from REDCOR® weathering steel. It collates essential guidance to assist the Australian industry with the efficient and appropriate application of weathering steels in bridge projects. The guide also provides practical advice to help achieve the expected performance and planned design life of these structures in local conditions.
Videos
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Sustainable Corrosion Protection Systems for Steel Bridges Using LCAThis design guide applies HERA’s Low-Carbon Circular Design Framework to steel and steel-hybrid low-rise commercial buildings, outlining strategies for reducing carbon emissions. It includes case studies demonstrating over 50% carbon reductions through adaptable design, material choices, and disassembly planning. The guide also explores operational carbon reduction strategies for greater sustainability.
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Beyond Carbon – An Engineer's View to Addressing the Climate CrisisAddressing the climate crisis is the challenge of our generation, with a hard deadline and disastrous consequences. There are many views and conversations, some confusing, some conflicting, while others make sense. As engineers, the question is what can the construction industry do to meet our obligations and what can we do as engineers, to lead the way to a brighter future. In this webinar we outline an engineer’s view to addressing the climate crisis, using an agnostic approach to assessing construction materials, the development of a decision tree roadmap for low carbon design, designing for longer life multimodal structures, and identifying the opportunities and challenges to achieving the lowest whole of life embodied carbon and emissions.
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Feedback on B2 guidanceDesigning durable steel structures based on standard ideas and technical specifications 3404.
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Development of a novel corrosion prevention method for hidden internal steelwork in bridgesThis webinar will present the science behind the novel variable dehumidification method, and a whole of life net present value cost analysis between the different options. It will also provide an overview of the proof of concept trials on a Welsh Rail Underbridge and on the Auckland Harbour Bridge, schematics of the dehumidification system, and the use of real time monitoring sensors to safely ascertain the efficacy of the developed method over the upcoming 12-month trial period.
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Designing a Novel Low-Carbon Bridge SuperstructureExplore innovative solutions to reduce the carbon footprint of bridge construction. This webinar will delve into a novel bridge superstructure that integrates steel/concrete composite and Timber Concrete Composite (TCC) systems with what our engineers have named a Composite Hybrid Bridge (CHB) system.
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The Case for Steel Road Bridges with a Low Carbon FootprintThis webinar presents the case for the design of steel road bridges with a low carbon footprint, by using current carbon life cycle assessment (LCA) best practice, comparing a conventional steel/concrete composite ladder deck bridge and a timber hybrid alternative. In addition to providing the results of the LCA, the webinar will also discuss the identified limitation of current carbon accounting practices, especially relating to the assumed end of life options of the construction materials, and concludes with recommendations for bridge engineers on reconsidering our approach to designing truly sustainable bridges.
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The Future of Digital Bridge Asset ManagementUnlike new bridge structures, building and managing a digital twin model that forms the basis of existing bridges operational and maintenance management is a more challenging prospect. This is especially an issue when dealing with “big bridges”, ranging from the Sydney Harbour Bridge to the Golden Gate Bridge. This presentation collates learning from Asset Owners experiences, an overview of WSP’s Digital Twin Maturity Model, the importance of collecting the right data and what to do with it, the pathway to the development of the Auckland Harbour Bridge digital twin vision, and the development of a network-wide digital twin. It concludes with our proposed framework to develop a cost effective, agile and modular digital twin model that forms the basis of a Digital Bridge Asset Management (DiBAM) solution.
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Compass 2024 Video - An Engineer's Approach to DecarbonisationThis Compass 2024 video, presented by COLORBOND® steel, features Raed El Sarraf, Principal Engineer at WSP, one of the world’s largest engineering and technical services firms. A passionate advocate for building lifecycles, the stewardship of steel, and the intersection of engineering and sustainability, Raed shares an engineer’s perspective on decarbonisation.
Podcast episodes
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Ep. 100 | Constructing for resilience and durabilityThis episode explores why resilient, durable infrastructure is fundamental to achieving a more sustainable, lower-carbon future. In this podcast, Raed El Sarraf discusses how sound engineering decisions during design, construction and maintenance can significantly extend asset service life, reduce whole-of-life costs, minimise environmental impacts, and improve the long-term performance and reliability of our built environment.
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Ep. 38 | Weathering SteelRaed El Sarraf provides an overview of the latest revisions to New Zealand’s guidance for the design and use of weathering steel bridges. Discussing key factors influencing long-term durability, including environmental suitability, structural detailing, fabrication, construction, inspection and maintenance.