Bulk Engineering, Technical articles

The need for a revised AS 3774

Daniel Ausling and Mark Todd of BG&E Resources, a corporate member of the Australian Society for Bulk Solids Handling (ASBSH), write on the importance of engagement between industry and academia for the continual development of fit-for-purpose, novel designs, and design practices. The ASBSH is committed to advancing the industry through research and best practices.

Daniel Ausling and Mark Todd of BG&E Resources write on the importance of engagement between industry and academia for the continual development of fit-for-purpose, novel designs, and design practices. Ausling is a member of the Australian Society for Bulk Solids Handling (ASBSH), a technical society committed to advancing the industry through research and best practices

As it is now widely known within the industry, AS 3774 was withdrawn recently as it had not been revised by an active technical committee for an extended period. Since that withdrawal, the bulk solids community has been having the discussion regarding revising AS 3774 – updating with recent developments in the bulk solids handling field and bringing into line with related standards – or adopting EN 1991.4 (commonly referred to as “the Eurocode”). The authors note the recent article in a previous ABHR edition as well as the discussions held at the 14th International Conference on Bulk Materials Storage, Handling & Transportation (ICBMH) 2023 conference and statement released by the Australian Society for Bulk Solids Handling (ASBSH). 

For the reasons discussed below, it is the firm belief of the authors that industry would be best served by the revision of the Australian Standard as opposed to the adoption of the Eurocode.

Non-standard applications in industry

Over the course of 2023, two bulk solids related projects being undertaken by BGER highlighted the limitations and possibly incongruent approaches regarding the current design standards and specifications used in industry. The two projects were related to:

1. Truck load out (TLO) bin: Treatment of non-standard bin geometries with regards to loads imposed by bulk materials.

2. Lateral stockpile pressures: Lateral stresses imparted at stockpile bases from the perspective of bulk solids, and alternative theories including geotechnical approaches and the design methods used by structural engineers for retaining walls.

Figure 1 – Truck load out.

The first issue presented itself via a truck load out for rejects material (Figure 1). This load out was essentially a squat container with a tunnel passing through and an open door proposed on the side for material clean out when needed (Figure 2).

Figure 2 – Truck load out sans bulk material.

Basic interpretation of AS 3774 and EN 1991.4 would dictate that the stresses be treated as hydrostatic in the lower bin sections. This leads to large separation forces between the concrete tunnel and bin walls. Intuitively, this approach, for anything other than a Newtonian fluid, does not yield a sensible solution. BGER performed enough background work with DEM modelling (Figure 3) to provide an indication that indeed the forces expected should not be hydrostatic but rather decreasing as the junction between bin wall and tunnel is approached (Figure 4). However, preliminary investigations do not suffice in circumventing an approach taken by a standard. 

Figure 3 – TLO – DEM representation.
Figure 4 – TLO – DEM Normal Wall pressures.

The second issue regards the commentary provided by bulk solids handling theories on the lateral pressures created at the base of stockpiles and how that compares to established geotechnical theories. The practical outcome of such theories is the stresses endured in the concrete structures at the base and edge of a stockpile, and which approach should govern the resulting design parameters. Bulk solids handling theories present a shortfall of information and approaches whereas, BGER would argue, the static theoretical approach dictated by geotechnical theory presents an overly conservative design envelope (Figure 5). 

Figure 5 – Lateral pressures at stockpile base – existing geotechnical theory.

Both these problems give rise to the potential of a collaboration with a tertiary institution to review the existing theories, conduct relatively simple testing, determining if existing theories are appropriate or further study defining a more complex scope that can lead to improvements of industry practice.

Need for an Australian-focused bulk materials loading standard (AS3774)

In a related consideration, the authors wish to bring to focus either of two realistic outcomes regarding the withdrawal of AS 3774. The first is the adoption of the Eurocode – this is a more modern standard written within a suite of standards all aimed at use within the Eurozone. Naturally, it follows that the application of the Eurocode to Australian settings may expose gaps with the approaches taken within the standard. One such gap is highlighted with the truck load out case discussed briefly above – the Eurocode does not treat this application with any custom consideration and, as such, would dictate the continued use of a hydrostatic pressure development within the bulk material and transferred into the container structures.

Hence, it would seem to the authors that an opportunity exists in the potential revision of AS 3774 to address current shortfalls (such as the TLO treatment) as well as updating methodologies in line with research conducted over the last 20 years (example, vertical gate load pressures imposed over time by a bulk material). The best outcome for Australian industry is the revision of AS 3774, with the Eurocode only being adopted, if necessary, in the interim period.

Collaboration with the University of Newcastle

Given the University of Newcastle’s history in applied research in the field of bulk solids handling, a natural recourse was to refer these non-standard applications into the research space in the hope that meaningful developments result, and design practices are eventually improved – in reality, this is a minimum 5-year process.

TBS and the University of Newcastle (UoN) has a long history of industry engagement. This approach has been developed and championed by the founding director of TBS, Emeritus Professor Alan Roberts, and is carried forward by several members of the team including Dr Bin Chen, Professor Craig Wheeler and Dr Peter Robinson. 

Figure 6 – TLO – Theoretical consideration of container as series of reducing radius silos.

Through the industry engagement process, each of the two problems discussed above were put forward to the university as areas potentially worthy of research. The first step is defining a scope of work for an engineering final year project (or embedded honours project) that are a part of all engineering undergraduate degrees. BGER and UoN combined in this effort to create a scope suitable for an honours project that, although simplified, was still relevant to the original industry problems. Industry (BGER) and academia (UoN) can then collaborate to supervise the direction of the work of the undergraduate student over the course of the project (typically 1 year). Where an honours project identifies opportunity for further progress in a study area that may have benefits or applicability to industry, the natural progression is to a doctoral thesis (PhD), which, with its wider, more detailed and more defined scope, has the opportunity to drive forward fundamental knowledge and design practices.

The continued involvement of industry in all stages of the process is critical in directing research efforts to remain practically relevant. Industry has a very real opportunity and responsibility to drive research in a way beneficial to the wider sector. Recognising that this process is a lengthy one only serves to highlight the importance of a continual engagement between industry and academia so that gradual industry progress may be realised over time.


Through the practice of engineering within any Australian sector, cases will inevitably arise that highlight a current shortcoming of a standard design methodology. It is through continuous engagement with the academic sector that these shortcomings are addressed, and progress is made for the industry as a whole. BGER prides itself on its emphasis on technical excellence for its staff, as well as engagement and contributions into the tertiary education and research sector to help drive sector growth and help develop the next generation of engineers. 

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