Presentation on theme: "RTC2012-Confidence in the Final Geometry – Detailed Coordination, Prefabrication, Multi- Trade Preassembly John Mack Herrero Contractors, Inc."— Presentation transcript:
RTC2012-Confidence in the Final Geometry – Detailed Coordination, Prefabrication, Multi- Trade Preassembly John Mack Herrero Contractors, Inc
John Mack VDC / BIM Department Manager at Herrero Contractors, Inc. 26 years in the construction industry Last 3.5 as a general contractor Previous 22.5 years in the mechanical and plumbing industry Doing BIM/VDC for 18 years – Union trained plumber – Ran detailing department for two large mechanical contractors – Helped design software for third party AutoCAD and Project Management programs Been involved with Lean Construction for 7+ years. Participate with Lean Construction Institute (LCI), Center for Integrated Facility Engineering (CIFE) and Project Production Systems Laboratory (P2SL). President of the San Francisco Navisworks User Group (SFNUG).
Established 1955 Second Generation Family Owned Business Areas of Operation: Northern California and anywhere else our customers take us Construction Employers Associations safety award for the past four years Primary focus is Integrated Lean Project Delivery Providing Preconstruction and Construction Services All Projects Done Using VDC Full Time VDC Employees Higher Education For Other Examples Visit Our Website at www.herrero.com K-12 Schools Healthcare Hospitality Historical Restoration and Renovation Affordable Housing Residential Retail Tenant Improvement
Topics Qualifying the Background Models Establishing the Team Building Coordination –Few RFIs and Change Orders During Construction Layout Fabrication, Delivery and Installation –Cost Savings in the Field More Prefabrication Just in Time Delivery to Field Smaller Crews Sizes o Better Safety Better Field Productivity Less Rework
Does the model match the dimensions Can the model be used for clash avoidance / building coordination Can we use the model for model based quantity takeoff Can we use the model for model based estimating Can we use the model for time based field simulations Can we use the model for field layout Is the architect willing to partner with us to make the model usable for any of the above items that do not work Qualifying the Background Models
Bringing the Team Together The lingering question…When do we bring the trade partners on board? –Current methods suggest that TPs are brought on during CD phase –Sometime in during late SD to Early DD is best to start qualifying the models and documents What trade partners are needed early? –Steel Fabricator, Metal Framer, HVAC (wet and dry), Plumber, Fire Protection, Electrical, Dry Wall, Data and Security Wiring (cable tray) –Steel Fabricator is the most important to bring on to eliminate redraw based on structural installation. This is a top reason for redraw Why are the TPs needed? –Work with design team to make model and drawings reflect the actual construction –Start team building between trades, builders and designers to get in tune with the project at an early phase to speed up the construction –Minimize RFIs and Change Orders during construction
The Collocate or Not The Collocation Benefit –Shared server allows for real time drawing updates. –Coordination is done all week long while modeling. –Ease of communication with other trades in room. –Shared resources such as plotter, printer, fax, etc. –Good to have a place for a projection screen. If no Collocation –Establish set coordination meetings once a week that everyone can meet online. 1 st & signoff meeting in person –Understand that more than one meeting a week is disruptive to model production. –Look into setting up some kind of distance collaboration for non-meeting days.
Creating the Model Define the purpose of the model. –Why are you building a model? –What do you want to gain from it? Electronic Data Exchange. –How are you going to exchange data? FTP, Buzzsaw, Projectwise, some web based software, CDRoms using sneaker net. –Get access setup for everyone as soon as possible. Eliminate Waste –Try to draw in series instead of in parallel. Establish a point that the drawing of the model changes hands from design team to construction team that works for your project. This will vary on every project based on team expertise and schedule. –Use products like Navisworks on a projector screen for clash detection instead of light tables. More precise and less time needed. Keep Trade Partners Working and Same Pace
Planning the Process Model the Problems You Need to Solve Defining Information Needed Data Hand-Off vs. Collaboration Reduce Redundant (or Un-needed) Information Define Data Exchange Methods Early Set achievable goals for team and assign to performers
Process Issues / Questions Development of explicit handoffs between team members Tracking of the latency of responses during the design coordination process Development of explicit process goals and value stream at the beginning of the process (purpose of model, prefab etc.)
Level of detail drawn in model. –Dependant on what phase the of project. Hangers, supports and seismic. Misc. metals Small pipe and conduit. Structural steel bracing and gussets. Junction / Pull boxes. Bus duct. –Carry over lessons learned from past projects on what worked and did not work. –What the team feels is valuable. Caution!! –Too much detail can cause CPU crashes. –Software seems to be ahead of the hardware. –All 3d project may result in floor plans to be broken down into small pieces to be productive. Avoid crashing and slow drawing regeneration. –Vista 64 bit seems to help, but not a full solution. Establishing Level of Detail
Laser Guided Layout: Total Station A total station is an optical instrument used in modern surveying. It is a combination of an electronic theodolite (transit), an electronic distance measuring device (EDM) and software running on an external computer
Background with layout and survey points-3876 points to layout
Total Station Setup Tripod and Beam Clamp Usage
Layout on metal deck Left Picture: Sheet Metal Strap Right Picture: Pipe Hangers
Lesson Learned: Must Haves Proper training from vendor is a must Do not change crews if possible Use composite crew to save multiple setups in same area Teach the user how to add points to the layout in the field General Contractor buy in –Control lines from G.C. –Scheduled time for Total Station layout to minimize floor congestion A couple hard dimensions for manual verification Mount unit as solid as possible – minimal vibration ACCURATE DRAWN MODELS to for Layout Dimensions
Lessons Learned: Pros (Pluses) Saves time in field Saves time detailing –No need to dimension drawings. Layout is accurate –Do not have tape measure growth Trades can layout a floor simultaneously (using composite crews)
Lessons Learned: Cons (Deltas) Setting up the unit multiple times to cover an area can be time consuming. Information can be lost if system crashes. Limitations due to line of sight usage. Movement of floor can cause disruptions of service. Too many people in area can be frustrating Unit limited to file size. Shiny objects interfere with the beam. Too many boxes to keep track of. We built a custom gang box just for storage for the Total Stations.
Using the Model for Fabrication, Delivery and Installation
Pre-fab from 3-D Model & Just In Time (JIT) Delivery 1. 3D Model of Plumbing System 2. Bill of Materials from 3D Model 3. System assembled on site More confidence in pre-fab due to accurate 3D modeling Right material at the right time 50% more plumbing pre-fab than conventional
Sheet Metal Spool Sheet Spool sheet are used for sectioning and field installation. Pieces not sectioned are labeled, placed into carts with floor and building area marked on cart. This drawing accompanies material to jobsite. Later generation of spool sheets include column lines for field installation.
Duct Tower When large duct is sectioned, the duct tower is used. The tower allows assembly of 25 sections by one person, without the possibility of injuries due to heavy lifting.
Sectioned Duct for Delivery to Field Sectioned duct, labeled by floor, bldg. area and download number as defined on the spool sheet. All sectioned duct is sent to the site with wheels for ease of jobsite mobility.
Duct Wheel Assembly Duct wheel assembly. Wheel attaches to duct at the TDC, TDF or Duct-Mate flange and is held in place with a vice- grip c-clamp welded to the wheel assembly.
Less Rework = Savings for Owner Field Installation is an Exact Match to Model Re-work only 43 hours out of 25,000 hours HVAC Contractor had over $750K of labor savings on $9.04 Million GMP contract
Worth Repeating Partner Early Plan Properly Have the correct subs on board at start of project –Minimum = Mechanical, Plumbing, Fire Protection, Electrical, Data, Steel Fabricator, Metal Framer Track commitments All trades to provide a 3d model representing actual installation Keeping all subs drawing at the same pace BIGGEST: General Contractor participation and enforcement of coordination