Steel Detailing | Precast Detailing

Author: Dhileepan

  • Addressing Stair Landing Slopes with Steel Modifications

    Addressing Stair Landing Slopes with Steel Modifications

    In our previous blogs, we discussed common mistakes that can occur while detailing a stair landing with slopes. You can find the link to the previous blog here: https://www.tek1.com.au/australian-standards/designing-a-multi-level-staircase-common-mistakes-and-key-considerations/


    Now, the designers have replaced precast slabs with pavers. Since pavers cannot have varying thicknesses, we were instructed to do something with the steel structure to achieve the required falls.
    The stair landing system has steel frames, 10mm plates on their top & EA support members to bolt them. The 50mm pavers are placed on top of the 10mm plates.


    TEK1 played a key role in designing the modifications, adjusting the steel supports and slopes to achieve the necessary fall. If the required slope were unidirectional, achieving it would be straightforward. However, in this case, the stair turns 180°, and the mid-landing’s fall transitions in three directions.


    Handling Slope Transitions
    The landing below Flight-02 and the top of Flight-01 are in opposite 180° directions.
    A single rectangular plate cannot connect these two slopes seamlessly.
    To address this, we introduced two triangular plates in the middle to enable a smooth transition between the slope directions.


    Structural Adjustments
    The main steel structural members remain consistent throughout the mid-landing.
    We adjusted the RL (Reduced Level) and slopes of the EA support members to match the required slope of the 10mm plates that support the pavers.


    By implementing these changes, we successfully accommodated the required falls while ensuring structural integrity and proper drainage. This approach maintains a practical and efficient solution when using pavers instead of precast slabs in stair landings.

  • Melbourne Airport Gantry

    Melbourne Airport Gantry

    At Melbourne Airport, a gantry supporting a signboard spans 26 meters between laced columns without intermediate supports. The box gantry alone weighs 8 tonne. Since the gantry would bend because of to its self weight, pre-camber of 170mm was provided at the middle.


    For accurate representation, two models were created: one with pre-camber for assembly drawings and another without for general arrangement (GA) drawings. This approach ensures clarity in fabrication and erection, maintaining structural integrity while achieving the desired final alignment.

  • Designing a Multi-Level Staircase: Common Mistakes and Key Considerations

    Designing a Multi-Level Staircase: Common Mistakes and Key Considerations

    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.

  • Transforming 3D CAD Models into 2D Fabrication Drawings: The Orange Rope Project

    Transforming 3D CAD Models into 2D Fabrication Drawings: The Orange Rope Project

    Imagine trying to build a complex 3D structure using only flat, 2D puzzle pieces—every cut, weld, and alignment must be perfect. That’s exactly the challenge we faced with the Orange Rope project, where 3D CAD models had to be transformed into precise 2D fabrication drawings. How did we tackle this engineering puzzle? Let’s dive in!

    The “Orange Rope” is a series of rolled pipes placed between the piers in a bridge. This project involves a total of 11 ropes, with the following images showcasing a sample of a rope.

    Challenges and Solutions

    1. Converting 3D Models to 2D Fabrication Drawings

    The initial input received was in the form of 3D CAD drawings, while the required output consisted of 2D drawings for fabrication. To achieve this, the 3D ropes were broken down into a series of 2D pipe members, which were then welded together to recreate the 3D structure. Each rope was divided into 4 to 5 assemblies, each containing multiple 2D pipes that, when assembled, would form the final 3D shape.

    2. Welding and Alignment

    Welding each 2D pipe in the correct position to form the 3D structure presented a significant challenge. With intricate dimensions, aligning each pipe manually would be nearly impossible. To tackle this issue, a splice system was introduced. This system involved a welded plate with a nut affixed at the bottom of one pipe and a corresponding hole in the adjacent pipe. By bolting the pipes together through these holes, proper alignment was ensured before welding. Once the pipes were secured and welded, the bolts were removed, and the holes were plug-welded for a seamless finish.

    3. Asymmetrical Cuts for Base Plate Fixing

    Another major challenge was the presence of asymmetrical cuts in the pipes for fixing them onto the base plates. To ensure precise cuts, unwrapped views of the pipes were provided. These unwrapped views were printed on paper at a 1:1 scale and then wrapped around the pipe. This method allowed for accurate cutting directly from the template, ensuring proper fitment and alignment during installation.

  • Can You Spot the Mistake in This Stair Design?

    Can You Spot the Mistake in This Stair Design?

    Imagine you’re reviewing a staircase drawing, and you see this note:

    “8 THK CONTINUOUS FOLDED PLATE TREADS AND RISERS.”

    Sounds fine, right? But here’s the catch—is it actually possible to fold a single plate continuously for an entire stair flight? 🤔

    The Hidden Problem

    A plate cannot be folded continuously to form multiple stair treads and risers because:

    • Fabrication limitations – Bending steel plate repeatedly at stair angles is nearly impossible.
    • Structural concerns – Excessive bending weakens the material and creates stress points.
    • Installation challenges – A long, folded plate is difficult to transport and position correctly.

    The Right Approach

    Instead of one continuous folded plate, each tread and riser should be a separate, single-folded plate. These individual elements can then be welded or bolted together to form a strong and practical staircase.

    So next time you see a similar detail, take a closer look—is it actually buildable?

  • Staff Memo – Webmail Login

    Please use the following link to login to your tek1 engineering services mail: https://gvam1290.siteground.biz/webmail/mail/

  • The Importance of Proper Modelling for Non-Structural Plates: A Guide

    The Importance of Proper Modelling for Non-Structural Plates: A Guide

    When working with elements like cladding plates, balustrade infills, decorative panels, and chequer plates, the approach to modelling them differs significantly from that used for standard structural plates. Ensuring accuracy in these cases hinges on a thorough understanding of working points and the rotation property, which are essential for ensuring the correct orientation of the visible side when generating drawings or DXF files.

    Understanding the Critical Role of Working Points

    It might seem simple to assume that these sheets can be flipped or rotated as needed after they are cut. However, this is a common misconception that can lead to significant errors during fabrication. The key to avoiding such issues lies in setting up the working points correctly, particularly when dealing with intricate designs or surface finishes.

    The Importance of Proper Rotation

    Take a stair panel, for example. If the panel features any patterns or surface differences, the working point must run in the direction from left to right when facing the stair panel. Additionally, the rotation must be set to either “top” or “front”—never “bottom” or “back.” This ensures that the visible side of the panel is correctly positioned.

    Symmetry Doesn’t Eliminate the Need for Attention

    Even in cases where the pattern is symmetrical or there appears to be no pattern at all, the orientation of the face of the sheet is crucial. It’s easy to think that since the machine will cut the plate according to the DXF file, it doesn’t matter how the drawing is flipped or rotated. However, this is where problems can arise.

    Avoiding Aesthetic Imperfections

    During the cutting process, the machine can leave minor marks on the material. These marks are typically left on the non-visible side of the sheet. Therefore, it’s critical to feed the sheet into the machine with the correct side facing outwards. If not, the marks could end up on the visible side, compromising the aesthetics of the final product.

    Conclusion: Precision is Key to Quality

    Proper modelling and careful consideration of working points and rotation properties are essential when dealing with cladding plates, balustrade infills, decorative panels, and chequer plates. By ensuring the visible side is correctly oriented from the start, you can avoid costly mistakes and ensure a high-quality finish.

  • Enhancing Solar Chimney Design for New Market S1 Building

    Enhancing Solar Chimney Design for New Market S1 Building

    In the recent New Market S1 building project, TEK1 participated in various design review meetings, provided numerous markups, and involved in finalizing the design. This project involved 11 flats in one of the blocks, each featuring a solar chimney on the backside of the building.

    Amendment 1: Addressing Structural Frame Issues

    Initially, the structural frame for the solar chimney was composed of two PFCs on each side running between level-1 slab & the roof. One PFC was fixed to the masonry wall with chemical anchors at regular intervals, while the other was anchored to the sides of the slabs at two different levels. However, we identified a 195mm gap between the steel PFC and the slab due to varying opening sizes for the chimney in the level-1 and level-2 slabs in the architectural layout. With this gap, it was not possible to anchor the PFC to the slab.

    Through detailed markups and discussions, TEK1 and the structural team agreed to amend the steel frame. UB members were introduced between level-1 and level-2, providing a wider support anchored on top of the level-1 slab. The PFC members were shortened to run between level-2 and the roof, with the PFC and UB connected by splice plates bolted at the top and bottom flanges. This solution effectively addressed the support issue and ensured structural integrity.

    Amendment 2: Refining the Top Frame of the Solar Chimney

    At the top of the solar chimney, the initial structural drawings provided rudimentary details. With 11 solar chimneys of varying heights and only one section view in the architectural drawings, TEK1 proposed several sketches with different options to achieve the required heights. After receiving finalization from the architect, we collaborated with the structural engineer to discuss supporting the top frame to the rafters. Stubs were introduced at the top of the rafter to secure the design.

    Ensuring Smooth Project Flow

    TEK1 ensured that these discussions and iterative markups did not disrupt the project’s workflow. While the solar chimneys were under design review, we focused on detailing other areas and supplied drawings in stages. This approach maintained the project’s momentum and avoided delays.

    If you’re interested in having TEK1 manage your project, please send a quote request to our principal, Koshy, at koshy@tek1.com.au, and specify that you want Dhileepan to manage your project. We look forward to bringing our expertise to your next venture.

  • Ascham College – Streamlining Plant Room Construction for Safety and Efficiency

    Ascham College – Streamlining Plant Room Construction for Safety and Efficiency

    In a recent project, we encountered a challenge with a plant room constructed from SHS members, featuring grating on both the floor and the roof.

    Problem 1:

    The original structural drawings specified vertical splice plates bolted together. However, these splice plates would protrude through the floor & roof gratings, creating a potential trip hazard.

    Upon identifying this issue, we notified the structural engineer, who then changed the bolted connections to site-welded connections. While this solution addressed the trip hazard, it introduced a new problem: site welding approximately 40 splices would be both costly and time-consuming.

    When this issue was discussed with the fabricator, they proposed shop welding the SHS frames into just two large assemblies for the entire plant room which they had the capacity to transport as large units. This approach significantly reduced the number of site welds required.

    Problem 2:

    However, another challenge arose: these large assemblies were to be galvanised and were too big for the galvanising bath. We consulted with the fabricator regarding the maximum size of the galvanising bath and suggested subsequently splitting the plant room assemblies accordingly. This adjustment reduced the number of site welds to around 20, making the process more efficient.

    Two primary problems were identified and solved:

    1. The bolted splice causing a trip hazard: Transitioning to welded connections resolved this safety concern.
    2. Assemblies larger than the galvanising bath: Adjusting the assembly size to fit the galvanising bath ensured the integrity of the galvanising process.

    By identifying and rectifying these issues at the planning stage, we saved significant time and money.

    If you’re interested in having me (Dhileepan) manage your project, please send a quote request to our principal at koshy@tek1.com.au and mention that you want Dhileepan to manage your project.