Lot depends on what is the type of building, where is the stair, what is the asthetics required.
In a residential building, probably what matters most is the asthics for a millionaire residence, cost and asthetics for a middle class house and probably just cost for a low end residential.
(more…)Lot depends on what is the type of building, where is the stair, what is the asthetics required.
In a residential building, probably what matters most is the asthics for a millionaire residence, cost and asthetics for a middle class house and probably just cost for a low end residential.
(more…)Lot depends on what is the type of building, where is the stair, what is the asthetics required.
In a residential building, probably what matters most is the asthics for a millionaire residence, cost and asthetics for a middle class house and probably just cost for a low end residential.
(more…)
When designing a staircase, one of the most overlooked aspects is the correct distribution of risers, especially when integrating a mid-landing with a falling finish.
Understanding the Mid-Landing Design:
In this case, the staircase consists of two flights turning 180° with a mid-landing. The purpose of this stair is not only to provide access between Ground Floor (GF) and Level-01 but also to facilitate movement to the mezzanine level from the mid-landing. The design for the mid-landing incorporates a 10mm plate with a 50mm paver on top. However, an important requirement was added: allowing for a fall in the paver to prevent water stagnation.
We received an instruction to keep the landing RL 20mm lower than the door near the mezzanine level to incorporate falls in the paver.
Common Mistake in Flight-02 Design:
For a steel detailer, just paver RL which is 20 mm below the door level & 50mm paver thickness is enough to place the steel below. The sloping surface in the paver will be taken by some other parties. But the key thing to notice here is, the slope continues to the bottom of flight-02 as well.
At the end of Flight-01, the paver thickness remains 50mm.
Near the mezzanine door, the thickness increases to 70mm (50mm + 20mm fall).
A frequent error occurs when designing Flight-02. Many assume the risers should be evenly divided between Level-01 FFL (Finished Floor Level) and the RL of the mid-landing, neglecting the impact of the paver thickness variation.
To achieve the correct stair profile:
The mid-landing RL should be set based on the increased paver thickness near the flight-02.
Flight-02 risers should be distributed between Level-01 FFL and the actual top surface of the paver (which is 70mm at the bottom of Flight-02, not 50mm).
Else, the first riser in the flight-02 will be comparatively smaller than the rest of the risers.
Key Takeaways for Stair Detailing:
Account for varying thickness: Do not assume uniform paver thickness; adjust accordingly at different points.
Correct riser distribution: Ensure the risers of the second flight are calculated based on the actual mid-landing RL, factoring in paver thickness variations.
Clarify detailing instructions: Steel detailers do not need to model the paver exactly but must ensure the mid-landing RL is accurately set.
By paying close attention to these details, staircases can be designed more efficiently, reducing costly rework and ensuring a smooth construction process. Proper coordination between architectural and structural teams is essential to avoid misalignment and achieve a seamless build.
If you would like me to assist with your project, please send an email to koshy@tek1.com.au with your project specifications. Kindly use ‘Raj’ as the subject header.
When performing detailed engineering for commercial staircases and balustrades, it’s essential to ensure that all aspects comply with AS 1428.1 and the relevant provisions from the Building Code of Australia (BCA), particularly those regarding accessibility and safety. Here’s a breakdown of the critical points you must address:
Compliance with AS 1428.1:
1. This standard outlines the minimum technical requirements for accessible buildings. Engineers must reference the BCA to align with safety and access provisions. AS 1428.1 directs engineers to follow BCA for detailed requirements related to stair and balustrade design, ensuring all safety standards are met, particularly for disabled access.
2. BCA 3.9.1.3 – Riser Opening Requirement:
One of the key safety provisions under BCA 3.9.1.3 is ensuring that the riser openings on stairways are restricted. Specifically, the gap between treads must not allow a 125 mm sphere to pass through. This rule is vital for preventing accidents, such as children slipping through open risers. As a detailed engineer, you must ensure that this riser opening specification is incorporated into the technical drawings and calculations to meet safety compliance.
3. BCA 3.9.1.4 – Riser and Going Dimensions:
Further, BCA 3.9.1.4 provides specific dimensional requirements for stair risers and goings, as illustrated in Figure 3.9.1.2. This figure shows the maximum and minimum values for risers (R) and goings (G), as well as the slope relationship (2R + G). Engineers must adhere to these dimensions for both spiral and non-spiral staircases to ensure that the stairs are not only safe but also ergonomically comfortable for users.
4. Critical Figures:
Riser (R): Must be within the maximum and minimum values—115 mm to 190 mm for standard stairs and 140 mm to 220 mm for spiral stairs.
Going (G): Must be within the maximum and minimum values—240 mm to 355 mm for standard stairs and 210 mm to 370 mm for spiral stairs.
Slope Relationship (2R + G): Must fall between 550 mm and 700 mm for standard stairs and 590 mm to 680 mm for spiral stairs. These values ensure that stairs provide both safety and comfort.
5. Ensuring Compliance:
As part of the detailed engineering process, it’s your responsibility to ensure that all specifications, such as the 125 mm riser opening limit and the exact riser and going dimensions, are strictly followed in the drawings, materials, and construction processes. This involves validating these measurements on-site and ensuring they are reflected accurately in both the design and construction stages.
In conclusion, the detailed engineering process must ensure compliance with AS 1428.1 and the BCA, particularly regarding the requirement that the riser opening must not exceed 125 mm, as outlined in BCA 3.9.1.3. Additionally, the riser and going dimensions must conform to the standards specified in BCA 3.9.1.4. By adhering to these standards, you will ensure that commercial stairs and balustrades are safe, accessible, and compliant with Australian building regulations.
If you would like me to assist with your project, please send an email to koshy@tek1.com.au with your project specifications. Kindly use ‘Raj’ as the subject header.
Australian Standard AS 1428.1.
This guide emphasizes key elements in designing safe, compliant buildings that align with the Australian Building Codes Board (ABCB) standards for fall prevention, especially around barriers and handrails. These regulations aim to protect all building users, especially vulnerable groups such as children, from potential fall hazards.
CONCRETE:
(AS 1379 Specification and supply of concrete) A mixture of Cement, aggregates and water with or without the addition of chemical admixtures or other materials.
Cement: (AS 3972 Portland or blended cement) A hydraulic binder composed of Portland or blended cement used alone or in combination with one or more supplementary cementitious materials.
Concrete is defined as follows,
Concrete in the state between completion of mixing and initial set as defined in AS 1012.18 Methods of determining setting time of fresh concrete, mortar and grout by penetration resistance.
Concrete after initial set, as represented by test specimens that have been subjected to a specified process and duration of curing.
Concrete that is specified primarily by a standard compressive strength grade up to 50 MPa and otherwise in accordance with Clause 1.5.3.
Concrete that is specified to have certain properties or characteristics different from, or additional to, those of normal-class concrete and otherwise in accordance with Clause 1.5.4.
SPECIFICATION OF CONCRETE:
Concrete shall be specified,
(a) as either
(1) Normal-class(N), or
(2) Special-class(S), or
(b) By strength grade or other readily verifiable parameter by which compliance with the specification can be assessed.
NOTE: Standard strength grades should be specified wherever possible.
Normal-class concrete shall be specified only by the parameters given in Clause 1.5.3.2(Basic parameter), and shall have the following attributes:
NOTE: This maximum value of 1000 × 10−6 is consistent with the use for design purposes of a median basic shrinkage strain value of 850 × 10−6.
Basic parameters of normal-class concrete:
The following basic parameters shall be specified by the customer:
NOTES:
NOTE: If unspecified, it will be assumed that project assessment is not required.
(2) SPECIAL- CLASS CONCRETE:
Concrete other than normal-class concrete shall be specified by the customer as specialclass and, if applicable, by strength-grade. The parameters and attributes that should be specified for special-class concrete should be as set out listed below with reference to Appendix B and Table B1 on AS1379.
Special-class concrete commonly has the same basic parameters as normal-class concrete with some additions and(or) exceptions. Parameters or attributes that are different from, or additional to, those of normal-class concrete should be included in specification below. If the requirements of specification for any concrete are inconsistent with those for normal-class concrete then the requirements of specification take precedence for that concrete.
Where any parameter other than strength grade requires the specification of a special-class concrete, or the proportions of the mix are specified, the concrete should be identified by an appropriate code agreed to between the supplier and customer that identifies that particular mix.
Basic parameter for specification of special-class concrete:
S, for compressive strength grades;
SF, for flexural strength grades; or
ST, for indirect-tensile strength grades.
Where concrete is special-class and any property other than strength grade is Specified as the principal criterion, or the proportions of the mix are specified, it is designated by an appropriate alphanumeric code, agreed between the supplier and the customer, to indicate the criterion.
NOTE: A summary list of several such parameters, some or all of which may be specified for the production of special-class concrete for a project, is given in Appendix B on AS 1379.
Applicable stairs, and ladders require compliance to:
How can you test whether you know the standard? Take our online test – all detailers must pass this before they are allowed to detail any stair.
Contact us for your detailing requirements.
Tek1 has set up an online training course to train our detailers on stair standards.
We have found this as an effective way of testing
Here is the URL. Please register your interest so that we can make it available to you. If there are enough interest, we could make this course self registering
Analyze load transfer before blindly applying connections.
Here is a markup from the engineer, which is right. The load from the UB350 beam is not transferred to SC7. Hence 4 bolts not required.
