When designing reinforced concrete structures using traditional methods such as 2D drawings, you may encounter some typical challenges. One classic example is that you might be spending many hours redoing or amending the same designs repeatedly. As a result, this may squeeze the overall project schedule and even cause it to slip, with the knock-on effect of increasing project costs. This example is not the only one slowing down your project and also damaging your business.
Here some of the most common pain points of 2D rebar detailing and some ideas on how 3D design tools can help you overcome these challenges.
Challenge 1: Rebar clashes with the neighbors’ bars and structures
Your rebar design clashes with neighboring rebar detailed on a separate drawing. This might occur for two reasons. On the one hand, you might be working on a flat 2D drawing, in which real shapes are not easily visible. Or, on the other hand, you might be using many drawings to detail various reinforcement parts without putting all pieces together. As a result, your rebar fixer will only be able to identify the clashes until work begins on-site.
When using 3D design tools, all reinforcement is shown in a single 3D model. Due to the visual nature of the 3D model, the reinforcements are displayed in their full geometries instead of only showing confusing and overlapping lines. As a result, any clashes with neighboring elements are identified much earlier in the process, and viable solutions can be found before issuing the drawings and ordering the bars. This translates into direct savings in time, materials, and resources on-site.
Challenge 2: Small rebar design errors leading to high costs
In a 2D drawing, some of the bars may be incorrectly specified. Sometimes a simple typo error might cause many inconveniences in a 2D design world. Let’s say that a bar is marked as #4 instead of #14 in the shop drawing. After bars are fabricated based on the drawing and considering that there is a 30 millimeters difference in diameter between these bar sizes, there is no way to fix this mistake on-site. You will need to order new bars delaying your project schedules, wasting material, and increasing your cost.
When viewing a 3D model of the construction, any minor errors such as typos can be easily spotted and corrected. This is because different types of bars are distinctively and automatically marked, each with their own color-coding. 3D shows bars as those look in real life, and adding color to the bars makes it easy to identify if something is wrong at an early stage.
Challenge 3: Something important is missing from your rebar detailing
When creating complex reinforced concrete structures in 2D, it is not uncommon to accidentally leave some of the rebar out of the plans. Among many flat lines, you might be thinking that you included something that you did not. These omissions may be noticed only after drawings have been issued. And, you might need to do the work again.
In a workflow that utilizes 3D tools, all the parties in the project can review the model from early on. Having more eyes on the model will help to spot the missing parts on time and increase collaboration. Besides, with this level of transparency, the constructability of the design, and the entire construction process can quickly be reviewed. This ensures that every required rebar can be accounted for, and the rebar process fits the whole workflow.
Challenge 4: Adding new details to rebar drawings takes time
In the course of the design process, you may notice that specific details or sections are missing or have changed and should be added. This can be quite tedious, manual and time-consuming work when doing it in 2D. You might need to track different versions of changes and make new drawings for these extra details.
When using 3D design tools, you can quickly create new sections or views and add them to the 3D model. All the parties in the project can also immediately see and give feedback on the changes. The drawings are created automatically, so there is no need to create a model and drawings separately. In fact, you can get all your deliverables from the model.
Challenge 5: Rebar congestion at lapping points
Lapping locations are a key point in rebar design. Unfortunately, they might get overlooked in 2D drawings. It is easy to get the lines mistaken for “just lines” and not rebar that must fit together correctly at the lap, but more often than not, you find that these just won’t fit, which can cause clashes or congestion on site. This means extra work and therefore, more costs.
When using 3D design tools and a constructible model, any congestion or clashes can be easily identified. This is thanks to the preliminary models that can be created at the start of the detailing process, based on the design intent. The project parties can identify any of these high congestion issues early on in the project, and they can be corrected before the construction work begins.
Challenge 6: Rebar clashes with other trades and installations
When the actual construction begins, collaborators from many different trades start working on-site and begin to put all the pieces together. Unfortunately, it is common to find that the various designers and contractors create separate 2D drawings and work in silos. They often work without integrating the entire construction design, until the point that construction takes place. They might find clashes between different structures such as rebar and mechanical & electrical systems, or between rebar and temporary installations.
Collaboration is essential to succeed in and speed-up any construction process. These kinds of clashes can be avoided by using a constructible model. A suitable software allows you to import models and drawings from other designers and detailers and integrate those. As a result, you get a model with all the information you need to fix your reinforcements smoothly and without clashes.
Working in 3D benefits all parties
Many of the challenges of working in 2D are related to lack of communication, shared understanding, and collaboration between the project’s stakeholders such as the rebar designer, the structural engineer, the contractor, and the sub-contractors. Using a 3D model enhances the accuracy and constructability of designs, and it can improve communication.
This even gets better by adding an online collaboration platform to bring all the project parties together. In this way, they can see all the different designs pulled together – and give their comments at the most important phases in the process. The rebar detailer can then easily make changes and additions based on everyone’s input before the drawings are finalized and issued. This improves the overall quality of the project and helps everyone in the project to see the bigger picture and use their time effectively.
Source: Tekla Blog