With today’s changing construction industry landscape, building construction projects are getting stiffer as far as economics and risk management are concerned. Project finances are suffering, risks are increasing, and contractors are always in the crunch of money, time and labor.
As the project advances to the construction stage, more challenges start surfacing. Construction companies and general contractors embark on to shop drawings and Request for Information (RFIs) where enhanced management is found. To manage every service offered by the construction company, onsite engineers and contractors leverage shop drawings and steel shop drawing to manage their activities with fabricators and sub-contractors.
But even shop drawings are eccentric in assisting contractors when everything is haywire on site owing to mismatching of data at multiple technical levels.
Drawings discrepancies and challenges on construction site
The most common challenges that contractors encounter on site are the gaps in drawings and actual construction owing to geometrical differences between the AutoCAD shop drawings, construction drawings and submittals from two separate sub-contractors. When foremen on sites come across such discrepancies, they start creating havoc and it becomes difficult for the engineers to manage.
Although the engineers generate RFIs for clarification, there is a considerable time lag between the receipt of RFI, sending a response, and finally acting upon it. Until then the construction work progress on site is set on hold. Revisions are then carried out by resolving the issues whatsoever.
But between all the hustle, construction work suffers; and it counts for all the monetary losses, stoppage on the generation of ROIs and labor charges. Additionally, the entire construction timeline that was planned earlier gets delayed, or in some cases, disrupted entirely.
Coordinating cross-disciplinary activities
When such challenges of coordination arise, the pre-planned construction schedule is disordered. This not only leads to delays but also poses as challenges at multiple levels, especially for cross-disciplinary actions. For example, when plumbing fixtures and electrical fixtures are to be installed, it might lead to reworks, reduction in efficiency, or in worst cases, accidents.
Furthermore, installation of prefabricated materials like columns, beams or even building products like sheet metal ducts, fixtures like frames for doors and windows etc. too cause challenges at multiple levels because of prior delivery commitments from fabricators and sheet metal contractors. Even when the steel shop drawings or fabrication shop drawings provided to fabricators by sheet metal design engineer are accurate, they might not be in sync with building models. And when there are slight geometrical deviations from the planned designs, alignment is a challenge.
Extracting shop drawings from as-built BIM models
Ideally, shop drawings extracted from the as-built drawings and Revit BIM models of the building, chances of dimensional deviation are reduced automatically. Fabrication shop drawings contain comprehensive details related to construction works and installation of prefabricated building products as well as building elements with specifications, schedules timeline, and information that is specifically assembled by a contractor. Additionally, they also have contractual terms and conditions of the project, and the contractor is liable for breach of any contractual obligations.
The benefits of doing so not only reduces the progress of construction activity but also obstructs the blames since every change can be tracked in the common data environment of BIM. The blame game is eliminated and productivity cannot be hampered. The designers, architects and engineers can constructively contribute by managing and scheduling fabrication shop drawing submissions, giving them a room to make efficient decision making process.
Role of Designers and Engineers should then be restricted to:
- Technicalities of shop drawings
- Finalizing changes as per shop floor capabilities
- Scheduling submittals to contractors and managing the time
- Approve/Manage reviewer’s suggestion on shop drawings
Tips to work around with Revit BIM and shop drawings in CAD
Once the details of building geometry is extracted and relevant information is imported to a suitable CAD platform such as Autodesk Inventor or AutoCAD, or SolidWorks, the designs can be made efficiently with appropriate tolerance and clearances. Appropriate manufacturing information, sheet metal characteristics, DFM guidelines etc. can then be followed which reduces changes orders and revisions to a considerable level and misalignment can completely be avoided.
Assigning a reviewer to review shop drawings is a good strategy. It eases and streamlines downstream activities as reviewer decides whether the fabrication shop drawing is accurate from every building design and construction perspective or if it needs to be sent back to the respective contractor for revisions.
Reducing risks and liabilities by defining roles and responsibilities within contracts
When roles of every contractor, sub-contractor, site engineers, etc. within the construction firm for any project that they undertake it is easier to track the changes as well as liability of the drawings can be reduced. Likewise, the reviewer is also more likely to make sensible changes by examining the drawings with multiple aspects in mind.
Thus, risks and liability can be managed more efficiently when roles and responsibilities are defined clearly in the contract and lesser RFIs are generated as the shop drawings become more comprehensive.
Moreover, when shop drawings are comprehensive, installation and assembly too becomes hassle-free with least reworks, waste and labor. Even coordination of activities is in place as planned during BIM coordination meetings and design professionals can utilize their time more judiciously. It gives clarity to all stakeholders involved as to what particular decisions are being taken for their concerned roles and responsibilities without any flawed action.
At TrueCADD, we deliver outsourced shop drawing services for sheet metal fabrication, steel fabrication as well as other production needs in construction projects. Email us at firstname.lastname@example.org to speak to our shop drawings experts and discuss your project requirements.