Do all buildings are EQP buildings from 80s in according to the Yellow Chapter C5(2018)?
In the Assessment guideline C5(2018), it says 665 mesh cannot be relied on to provide load path for floor diaphargm analysis. Does it mean all buildings built from 90s to 2000s all become EQP buildings?
One example is teh DSA report prepared by Homles for Frank Kitts Carpark for Wellington City Council. In teh report it says:
Reference to the latest industry best practice, captured in ASCE 41-17 and the proposed revision of Chapter
C5 of the Engineering Assessment Guidelines (“Yellow C5”) has been made to provide commentary on the
expected seismic performance of this diaphragm. Yellow C5 and ASCE 41-17 state that an elastic analysis
can be performed where the total strain captures the effects from the segmental nature of the individual
components (e.g. the effects from shrinkage and creep are included in the assessment of strains induced in
the mesh reinforcement). Furthermore, Yellow C5 states that ‘non-ductile’ mesh should not be relied on in a
strut-and-tie type of diaphragm analysis.
This provides no solution, since an analysis that includes the effects from shrinkage and creep is deemed
impractical and expected to not result in reliable results. This is mainly due to the large number of sideeffects
that could significantly affect the parameters in the analysis. Attempting to identify and evaluate
all these parameters is impractical.
Therefore, the capacity of the diaphragm is considered inconclusive and the Engineering Assessment
Guidelines require this to be rated at 15%NBS (IL3).
In summary, most of the buildings designed and built in the 80s to 2000s are all falling into this category because it was common use of 665 mesh in that period. The implications are hugh, and, the economic implications are not NZ can bear. Are we, as an engineering profession collectively, creating an issue that we could not provide a solution?
Am I right or am I mis-intrepret the issue?
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