Staircases are an essential part of any multi-story building, providing access and connectivity between different levels. However, designing them is a complex task that requires a deep understanding of structural engineering principles, safety standards, and local building codes. In Australia, the Australian Standard AS1657-2018 plays a pivotal role in ensuring that staircases are safe, functional, and aesthetically pleasing. In this blog post, we, as a reputable engineering consultancy in Melbourne, will guide you through the key considerations for structural design when adhering to AS1657-2018.

Understanding AS1657-2018

AS1657-2018, officially titled "Fixed Platforms, Walkways, Stairways, and Ladders – Design, Construction, and Installation," is the go-to standard for staircase design and construction in Australia. This standard encompasses various aspects, including structural design, materials, dimensions, and safety requirements, all aimed at ensuring staircases are safe and functional.

Australian standards for stairs: a quick overview

There are three key Australian standards which outline requirements for the design, construction and installation of stairways:

• AS 1428.1: Design For Access and Mobility, General Requirements for Access - New Buildings
• AS/NZ 4586: Slip Resistance Classification of New Pedestrian Surface Materials
• AS 1657: Fixed Platforms, Walkways, Stairways and Ladders - Design, Construction, Installation

We've included a brief refresher below on the necessary requirements for designing safe, compliant staircases. Refer to the above standards for more specific information.

Flights and landings

The Australian standards for stairs and landings state that you can use a maximum of 18 stairs (risers) in a single flight. Flights can be connected using landings. A barrier, a landing 2+ metres in length or a change in the direction of the stairway of 90+ degrees needs to take place every 36 stairs.

Staircases must slope at an angle of 20° to 45°, but between 30° and 38° is recommended. Minimum headroom is generally 2 metres.

Stair treads

Stair treads need to be slip resistant and extend across the full width of the stairway. The edge of treads should be visible against the background. Slip resistant nosings can be added to meet these standards. Treads must be solid if the stairway is more than 10 metres high or connects more than 3 stories.

Risers, goings and depth

Key dimensions for the risers and goings of stairs are outlined in this table:

Additionally, the tread depth must be greater than or equal to 185mm. See AS1657 for details.

Handrails

Australian standards for stairs and handrails outline that staircases need handrails on all exposed sides unless there’s a fixed structure within 10cm of the stairway. Every staircase needs one handrail. Stairways wider than 1 metre need a handrail on both sides.

Loading

Stairs need to have:

• a minimum loading of 2.5 kPa.
• a 2.2 kN per linear metre.
• a minimum point loading of 1.5 kN applied on 10cm2 pad on each step.

This is one of the examples of the Spacegass analysis we carried out for our client. We carried out finite element analysis on the steel staircase treads under 2.2kN/m line load over 1200mm. The treads was a 3mm check plate steel plate and we have analysed using plate analysis with multiple mesh on nodes to analyse the result individually. We have also check to ensure deflection was L/100 or 40mm max, whichever is lesser. In this example, under the 2.2kN/m line load, it appears the max principal stress on the staircase is 41.18Mpa, with a deflection of nearly 5.44mm over 1200mm span. Therefore, based on our analysis, this design is satisfactory.

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Key Considerations for Structural Design

1. Load-Bearing Capacity: One of the primary concerns when designing a staircase is ensuring it can withstand the loads imposed on it. AS1657-2018 provides guidance on calculating live loads, dead loads, and other factors to determine the required load-bearing capacity of the staircase. This may vary depending on the building's intended use, and it's crucial to consult with structural engineers to perform accurate load calculations.
2. Materials and Construction: The standard prescribes materials and construction methods to ensure the staircase's durability and longevity. Common materials include steel, concrete, or timber. The choice of material should take into account factors like aesthetics, maintenance requirements, and budget constraints.
3. Handrails and Guardrails: AS1657-2018 lays down specific requirements for handrails and guardrails to prevent falls and accidents. Handrails must be designed and installed in a way that ensures a secure grip, while guardrails should be tall enough to prevent people from falling over the edge.
4. Tread and Riser Dimensions: The dimensions of treads and risers significantly impact the safety and comfort of staircase users. AS1657-2018 specifies the maximum and minimum dimensions for these components, considering factors like stride length and ease of ascent.
5. Balustrades: Balustrades provide additional support and safety to staircases. They are subject to specific design requirements, including height, spacing, and construction materials. Compliance with these guidelines is essential to ensure the safety of users.
6. Structural Stability: Staircases must be designed to be structurally stable, ensuring that they do not sway or vibrate excessively during use. Proper connections and fasteners are critical to maintaining stability and preventing accidents.
7. Accessible Design: In compliance with accessibility standards, staircases must also consider the needs of people with disabilities. AS1657-2018 includes provisions for ramps, handrails, and other features to make staircases accessible to all.

7 innovative staircase Designs

1. Floating stairs

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Floating stairs have been a major staircase design trend for almost a decade, fitting in perfectly with progressive minimalist architecture. But with an impossibly sleek look that dangerously defies gravity, are floating stairs compliant with Australian regulations?

The answer comes down to four major risk factors; handrails, tread gaps, stair surface and loading capacity. Designing a minimalist staircase in accordance with Australian standards for stairs and handrails requires careful planning, particularly with regards to these features.

2. Transparent stairs

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Another minimal stair design trend is transparent stairs and railings. These are made of sleek materials such as glass. Make sure you stay compliant by adding non-slip stair treads or nosings. Also, ensure stairs and handrails are visible at night and to those with limited vision. Add automatic lighting sensors and luminescent stair treads or illuminated handrails where necessary.

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3. Striking lighting

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Contemporary buildings often feature interesting staircase lighting, by illuminating various parts of stairs or playing on staircase shape to cast intricate patterns of light on the walls. These help ensure that staircases have adequate visibility.

4. Tiny houses

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Tiny houses are exploding in architecture right now, as they enter the commercial sector. They can even be 3D printed, with wireless smart technology being placed directly into the walls.

However, architects need to carefully plan two storey tiny houses in Australia. Staircase standards make complying difficult, as stairways can easily be too steep, shallow or close to the roof. We may even need to reevaluate Australian standards for stairs in light of the tiny house revolution!

5. Feature staircases

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Bold, striking and just plain huge feature staircases take the opposite approach to tiny houses - and they’re getting bigger and bigger. Large spiral staircases are a hit with many commercial spaces.

The great thing about large scale feature staircases is they are usually very robust, accessible and safe. Ensure they are built with the correct landings, handrails and dimensions in mind.

6. Bright colours

Vibrant, monochromatic staircases are huge at the moment. Often made from glass or metal, these are a great way to bring a staircase to life - particularly for projects with low light or a restricted budget. They are also easy to match with essential safety products like stair treads.

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Consulting a Professional

Designing a staircase that meets the requirements of AS1657-2018 is a complex task, requiring a deep understanding of structural engineering principles, safety standards, and local building codes. Therefore, consulting with a reputable engineering consultancy in Melbourne is highly advisable. Professionals in the field can help you navigate the intricacies of staircase design, ensuring that your project is not only compliant but also safe, functional, and aesthetically pleasing.

Conclusion

In Melbourne, as in the rest of Australia, staircase design is a complex task that requires meticulous attention to detail. Compliance with AS1657-2018 is not optional; it is essential to ensure the safety and functionality of your staircase. By working with a reputable engineering consultancy, you can confidently navigate the requirements of this standard and create staircases that are not only safe but also a testament to good design and craftsmanship.

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