Delegated design as set forth in construction documents for buildings, while an often-used instrument, can be misunderstood or poorly executed by the Owner, Design team, and/or Construction team, and result in disastrous consequences. The term ‘delegated design’ as commonly used in the AIA B-101 Contract between the Owner and Architect means that “if the Contract Documents specifically require the Contractor to provide professional design services or certifications by a design professional related to systems, materials or equipment, the Architect shall specify the appropriate performance and design criteria that such services must satisfy.”
The Key Parties involved include the Architect and Engineer
of Record, the General Contractor, the Specialty Contractor, and the Specialty
or Delegated Engineer; their relationship can graphically be described as
follows:
Typical delegated design items include stairs,
handrails, davits, structural steel connections, precast concrete components, elevator
support rails and beams, façade components and cladding, and other such items
where, ideally, the Contractor and the Contractor’s engineer can provide the
components by taking advantage of the Specialty Contractor’s means and methods
and provide that value to the Owner. The
delegated design may include unique attributes associated with the selected Contractor,
such as concrete strengths, manufacturing processes, glass types, steel
connection hardware, configurations of components, and specialty fabrications.
Owner
On behalf of the Owner, the Design team, consisting of the
architects and engineers included in the term ‘Architect’ above, decides
whether to delegate a portion of the design to the Contractor. Sometimes the designers believe they can
reduce their own labor costs by delegating some of the design, but commonly
this decision results in more time spent for the Architect in specifying the
performance and design criteria as well as performing a close review of the
shop drawings and calculations. It is
important to note that the Design team must coordinate all of the dimensional
aspects of the building in order to meet the Owner’s criteria for the use and
function of the space. This means that the
dimensions of delegated components must be worked out and coordinated by the
architects and engineers, not left to the imagination and whims of the
delegated Contractor and their engineer.
Design Team
In the graphic illustration above, the Architect of Record and
the Structural Engineer of Record are typically contractually bound to each
other, and responsible for the coordination of the project design. The delegated components are technically
delegated to the Contractor or Specialty Contractor, who engages the Specialty
or Delegated Engineer to design the components and connections. There is no ability, nor contractual mechanism,
for the Delegated Engineer to directly coordinate with the Architect of Record to
confirm wall thicknesses, beam depths, clearances, conceptual connections,
column locations and sizes – these must be worked out between the Architect and
Engineer of Record.
In some states such as Florida, there exist Administrative
Rules or Codes that prescribe the details required of the architect and
engineer in delegating the design of components. These can include the configuration (size,
spacing, shape) of the components, as well as details of supports, anchors, and
connections.
Construction Team
The Contractor may receive a set of drawings from the
architect and engineers (the ‘Architect’) that contain delegated designs that
do not sufficiently ‘spell out’ the appropriate performance and design
criteria, or that are missing the configuration and sizes of the components
such that coordination of the work will be required. In those instances, the Contractor should
‘raise the flag’ and note that the particular design has not been properly
delegated – and not just hope that the information can be flushed out during
the shop drawing review process. Again,
there is no contractual link between the Delegated Engineer and the Architect –
and therefore, the necessary coordination between disciplines cannot occur in a
proper and timely manner.
Summary
Delegated design can provide cost, schedule, and quality improvements for a building Owner if the Architect follows the guidelines for properly delegating the design of components to the Contractor, and the Contractor engages a Delegated Engineer who provides calculations and drawings for the component design in accordance with the performance and design criteria specified by the Architect.
Editor Thanh Do is an Associate in Thornton Tomasetti, Inc.'s Forensics practice group. As a structural engineer, structural failure analyst and investigator, Dr. Thanh Do examines infrastructure inadequacies and determines the root cause of the alleged failures. He specializes in Design-Build project delivery, quantity growth investigation, building collapse investigation, standard of care assessment, construction defects and design errors/omissions evaluation.
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