Everything in precast construction revolves around achieving the highest level of accuracy. The panels should be brought to the site in assembly form, ready to be clicked together like a puzzle, with nothing wrong. Although how panels relate to other parts of the building is very important, it is frequently overlooked in this process.
Errors in connection can result in problems such as long delays, cost overruns, a building’s instability or the removal of key elements by construction personnel. There is some good news. Many of these problems can be avoided if we pay close attention to detailing, coordination and communication.
Here is a list of five main areas to pay attention to when designing precast panel connections—and how to prevent typical mistakes.
1. Poor Coordination Between Disciplines
Frequently, the architectural and structural departments are separated in projects and design their models independently. As a result, there are serious problems with precast connections, including issues where connection plates bump into insulation, rebar gets in the way of embeds and joints are not properly aligned on-site. Good coordination helps to eliminate errors, prevent site conflicts and get approvals and inspections done more quickly.
How to avoid it:
- All disciplines should use a single BIM model to ensure they are using the same platform.
- Hold timely meetings and clash recognition sessions for architects, engineers and detailers.
- All team members should see and understand the clearly labelled connection locations before the drawings are final.
2. Ignoring Tolerances and Real-World Site Conditions
Even the best precast components may show a little variation during casting, transportation or when they are installed onsite. Should your design team not account for this difference, the panels might need to be fitted and changed on-site to work properly. Flexible parts mean that you can erect equipment more quickly and safely in difficult or limited places.
How to avoid it:
- Set up designs so that bolt connections allow for tolerances of 10 to 20 mm (depending on what is needed).
- Remember to add slotted bolt holes, bigger sleeves or space to insert shims, to make small adjustments.
- Mark each tolerance detail clearly in the drawings so everyone on site is aware.
3. Missing or Incorrect Hardware Placement
It is common to forget to add important things like lifting anchors, dowel bars or embed plates and even when these are present, it’s common to misplace them. Because of these requirements, panels may not be ready for use at the site or they might cause a delay in production. If hardware is properly and consistently positioned, installation will take less time, be more secure and keep money-making errors at a minimum.
How to avoid it:
- Automate the placement of hardware in BIM software using the parameters of its type, direction or length.
- All team members should follow an approved list of connection details.
- Make a QA checklist to ensure each insert and plate is present in the model before providing drawings.
4. Confusing Panel Numbering and Labelling
When the IDs on the panels do not match, site crews cannot correctly identify where they should place each panel. As a result, large construction projects, with numerous elements that are alike, can suffer serious delays and many mistakes during assembly. Numbering elements helps everyone locate and manage them more easily, install them faster and avoid confusion during construction.
How to avoid it:
- Assign special numbers to every panel by considering its wall type, level on the floor or direction of face.
- Tags and labels in drawings and model views will be generated automatically during design.
- Relate panel IDs with erection sequences, how panels will be moved and their storage arrangements.
5. Overcomplicating the Connection Design
Any project is different, yet including a lot of custom link types makes the system unnecessarily complicated. It complicates detailing work, makes products more expensive to make and ups the chances of errors at the project location. By standardising, we not only ensure better quality but also speed up training, making things and checking every piece.
Best ways to avoid it:
- Use connection types that your team and your fabricators are comfortable working with whenever you can.
- If a connected structure has been approved, just adapt it when it’s required.
- Work on simple, easy-to-use and compliant detailing that matches both design and construction standards.
Final Thoughts
The success of every precast project lies in the details of the connections between precast panels. Execution and design of these pieces guarantee durability, simple assembly and affordable costs. If website maintenance is ignored or not done properly, major issues may arise afterwards.
You should do three things to avoid usual mistakes: start coordinating from the start, settle on standard details and keep automation in mind. Using smart processes in BIM, talking clearly and making sure your paperwork is accurate will help you make no mistakes.
Our focus at NEOs is to help precast detailers achieve better results, faster and with a lower chance of error. We depend on advanced technology and BIM solutions to ensure all the connections are accurate, efficient and up to the task once they are in use.