In this, the owner contracts directly with the design-build team (normally a contractor with a design capability or working with an architect) to develop a well-defined building program and a schematic design that meets the owner’s needs.
The DB contractor then estimates the total cost and time needed to design and construct the building.
After all modifications requested by the owner are implemented, the plan is approved and the final budget for the project is established.
FIG-Adapted from workflow and deliverables for LACCD BIM standard on design-build projects (only the BIM-related workflows are shown).
Advantages to Owner:
It is important to note that because the DB model allows for modifications to be made to the building’s design earlier in the process, the amount of money and time needed to incorporate these changes is also reduced.
The DB contractor establishes contractual relationships with specialty designers and subcontractors as needed. These are usually based on a fixed price, lowest bid basis.
DB contractor will be responsible for construction and any changes to design (within predefined limits). The same is true for errors and omissions.
It is not necessary for detailed construction drawings to be complete for all parts of the building prior to the start of construction on the foundation and early building elements.
As a result of these simplifications, the building is typically completed faster, with far fewer legal complications, and at a somewhat reduced total cost.
On the other hand, there is little flexibility for the owner to make changes after the initial design is approved and a contract amount is established.
As design options are confirmed by the BIM model, design contingencies can be reduced and the construction schedule can be solidified. With more accurate scheduling and better cost take-offs, the risk and construction contingencies are reduced and the owner may be able to incorporate green features that did not initially fit the project’s cost model.
Risks Associated With Using Design-build on buildings
The design-builder ends up owning all the risk for the design as well as the construction of the building. Therefore, design-builders that subcontract out the design portion of the work must have adequate protections within their contract documents sharing the design risks with the appropriate parties. They should also examine master contracts with suppliers and other subcontractors to make sure their roles and responsibilities are clearly defined to ensure that the project’s goals are met.
Friday, July 8, 2011
Thursday, July 7, 2011
BIM for Owners
- Increase building performance through BIM-based energy and lighting design and analysis to improve overall building performance
- Reduce the financial risk associated with the project using the BIM model to obtain earlier and more reliable cost estimates and improved collaboration of the project team
- Shorten project schedule from approval to completion by using building models to coordinate and prefabricate design with reduced field labor time
- Obtain reliable and accurate cost estimates through automatic quantity takeoff from the building model, providing feedback earlier in a project when decisions will have the greatest impact
- Assure program compliance through ongoing analysis of the building model against owner and local code requirements
- Optimize facility management and maintenance by exporting relevant as-built building and equipment information to start the systems that will be used over the lifecycle of the facility
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