REBAR MODELING AND SHOP DRAWINGS
MB BIM creates 3D parametric rebar models where we model every piece of rebar on a project. The rebar placement drawings that are used by crews in the field, and fabrication data which is used by the rebar fabrication, are also extracted directly from the model. This process facilitates the coordination between the General Contractor, Fabricator, Installer, and Engineer of Record to incorporate project and shop specific efficiencies into the design and ultimately the installation.
The advantages of this delivery process include
Reduction in rebar tonnage: we often see a reduction in the amount of bar around 10-15% below what fabricators estimate. We believe this is mostly because estimators make conservative assumptions when estimating a project. This savings is significant because installers are paid based on what is shipped to site, so the concrete contractor is responsible for both the cost of the material and the labor to install.
Enhanced coordination: with all of the rebar modeled, the geometry of the concrete and rebar model actually matches what is formed (i.e. the rebar fits in the forms). We also reduce conflicts with embeds and resolve congestion/conflict issues in portions of the structure such as jambs of concrete core walls.
An additional advantage of this process in
Efficiency: we constantly look for opportunities to reduce the overall tonnage such as through the reduction or elimination of splices. With backgrounds in structural engineering, we identify these opportunities and also speak the same language as the EOR to facilitate incorporation into the design. Since we are involved in the lift drawing process and have a line of communication open to the design team, fabricator, and installer, we take an active role in providing a more constructible and better coordinated product. This reduces RFIs as the integrated approach allows questions to be answered quickly and in a less formal manner.
The final advantage of this service is
Field labor productivity: we identify and resolve any rebar congestion issues early and resolve those with the model rather than these things slowing crews down at the site, which ultimately increases field productivity.