Berkeley Way

The Process

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Key to the project success was initiating discussion with the concrete contractor early on to find mixes that achieved lower cement content without cost increase or time delay. During Construction Documents the team held meetings with the General Contractor, the concrete supplier, the structural engineer and Arup to analyze concrete mixes. They aimed for mixes with high cement replacements that would work structurally without adding significant time or cost. Having the team approach this together before the GMP process was helpful and got the team on the same page about goals.

During construction, there were multiple, last minute substitution requests. Some were due to seasonal fly ash shortages whereas others were to make the concrete pours simpler for the contractor. The former was dealt with by using mixes with slag only to replace cement instead of mixes with both fly ash and slag, which can have even lower cement. The latter was discussed by the design and construction teams before coming to an agreement on allowances that gave the contractor flexibility while still achieving high overall cement reduction targets. Throughout the submittal and substitution request process, the team needed to review the changes quickly, so the detailed tracking of the different mixes being used throughout different elements in the building, that Arup kept up to date, was essential.