Case Study: Miami-Dade Water & Sewer Department, 3-D laser scanning to BIM
In Florida, the Miami-Dade Water & Sewer Department is upgrading equipment at the Alexander Orr Water Treatment Plant. The existing pieces of equipment have been in service for many years. The new equipment will provide many benefits to the treatment of the water for Miami-Dade residents. The submitting engineering firm was tasked with designing the equipment upgrades as well as the structural, process, and electrical systems needed to support the new equipment.
The primary challenge the project team faced was that the building’s record drawings that house the existing equipment were not current with the existing conditions. Over the past 30-plus years, additions and modifications to the facility have been conducted. Having the existing conditions documented accurately prior to the commencement of design activities is paramount to identifying issues that will not have a negative impact on construction. To address these challenges, and to obtain accurate dimensional information and validate the locations of all system elements, the project team decided to conduct 3-D laser scans of the interior space in the two chemical buildings. The laser scans quickly captured accurate measurements of all equipment and systems located in the buildings. In addition, a 3-D intelligent model was created from the laser scans for use by the project team to coordinate and integrate the new equipment into the facility. A representative 3-D laser scan model from the project is shown in Figure 1.
The point clouds, a set of data points in a coordinate system, were generated by the 3-D laser scanner and delivered to the project team in Autodesk ReCap format. These files are easily referenced in most Autodesk products (i.e., AutoCAD, Revit, Navisworks) used to produce design documents. In addition to the point clouds, a 3-D intelligent model of both buildings was delivered in a Revit format. These deliverables allowed the team to digitally inspect and validate the new equipment against the existing conditions as the design progressed.
A few potential, but key, issues were identified during early design activities. For example, the new equipment connection to the lime silos was higher than the original. This prompted coordination with the client, the equipment manufacturer, and the project team prior to the 30% design submittal. Had this issue went unrecognized and made it through to construction, cost increases and schedule delays would have likely occurred. In addition, other system connections for water and electrical components were located in different positions than the existing equipment. The new process piping and electrical conduit routing was optimized to better integrate into the existing buildings.
Russell Tamblyn is director of VDC at CDM Smith and has been supporting BIM and VDC practices for 25 years on medium and large engineering/construction projects.
Timothy A. Verwey is manager of applied technologies at CDM Smith. He has more than 30 years of experience as a structural engineer designing cast-in-place concrete structures and multistory buildings.
Humayun Qureshi is director of production for global resource centers at CDM Smith. He has 24 years of experience in engineering design, engineering management, and global design-production initiatives, with a strong focus on leveraging tools and technologies to enhance design efficiency and quality.