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Block a – Design-Build: Develop Project Performance Requirements In
design-build, the project owner will develop project performance requirements before the tender design stage. These requirements will include the design specifications that are to be followed, including any local guidelines or practices. These may include defining the required subsurface
investigation requirements, procedures to be used for lateral foundation design, the maximum allowable resistance factors for design of laterally
loaded deep foundations, minimum lateral load testing requirements, and construction inspection and testing requirements. Many aspects of these are covered in the AASHTO specifications. However, this step allows the project owner the opportunity to specify deviations from or supplemental information to the AASHTO specifications. These may include site- or location-specific geologic models
for development of p-y curves, deflection criteria for Service or Geotechnical Strength Limit States, and/or minimum requirements for use of certain resistance factors (local
practice, etc. In general, the design-builder will use the maximum resistance factor allowed (in order to be competitive) unless the values of resistance factor
are tied to other criteria, such as local practice or load testing, in the project
performance requirements, and subject to the judgment of the design-builder’s designer. The project owner may want to specify or preclude the use of a certain foundation type, or include minimum requirements regarding analyses and testing for each particular feasible foundation type. Additional project performance requirements should be developed for
other aspects of the design, such as axial capacity, allowable settlement
and differential settlement, structural performance, etc.
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