Selected Stata construction defects
3. The amphitheater at the Stata Center was designed to be a mortared brick paving system over a structural cast-in-place concrete base. The risers and treads of the amphitheater required specific design considerations. Gehry addressed these considerations in its design. The durability of the system as designed, however, was dependent on the quality of the paving units and compatibility with the mortar system, the anchorage at the nosings, the slope of the paving surface, and the quality of the installation.
4. Gehry’s design for the Stata Center specified that the composition of the mortar bed include a latex additive to increase bond and limit water retention of the mortar, the anchorage at the nosings to include support of the three brick at the nose, and the slope of the paving surface at 1/4" per foot slope specifically so that water infiltration would be kept to a minimum. On the latter point, Gehry’s design specified that the concrete base was to be constructed with a specific slope to achieve the final surface drainage specified. Gehry’s design was, in these and all other regards, consistent with industry standard.
5. Skanska failed to comply with Gehry’s specifications and the quality of construction, for which Skanska was responsible, was below standard. This is the cause of the damages claimed by the Plaintiff.
6. As detailed in the reports of consultants retained by the Plaintiff, there were a multitude of problems with both the composition and application of the mortar. For instance, the thickness of the setting bed was excessive. Gehry’s drawings and specifications required a bed of 1 1/2", but the thickness of Skanska’s setting beds varied, with some as much as 4" thick. There was a poor bond of masonry to the setting bed and the composition of the setting bed was inconsistent and poor. The Portland cement particles exhibited variable, and often less than normal, hydration, indicative of a lack of adequate mixing water. The lime and Portland cement were not uniformly distributed, often occurring as isolated masses of hydrated lime with little or no Portland cement or masses of poorly hydrated Portland cement with only occasional inclusions of hydrated lime. There was evidence of extensive carbonation indicating exposure to and ingress of water during construction. Furthermore, poorly filled head and bed joints, the result of poor workmanship, were identified and there was a high frequency of entrapped voids, indicative of a stiff, dry mix. The construction defects observed by Plaintiffs consultants, such as voids in the mortar and mortar bed, corresponded to areas of excessive efflorescence.
7. The latex additive specified by Gehry for inclusion in the mortar was not provided as specified. Gehry specifically required the latex additive to limit the absorption of water into the setting bed and to improve bond. Testing of the mortar after demolition revealed that the latex was not uniformly mixed into the mortar and that, in some test samples, was detectable only in trace amounts.
8. Compounding the problem, the slope of the horizontal surfaces varied and fell below the specified 1/4” per foot requirement outlined in the drawings and specifications. This resulted in “ponding” water and caused intrusion of more moisture in to the brick and mortar. The goal of reducing the water in the system was exactly the motivation for the aforementioned design specifications concerning the mortar composition and application. Simply put, as a result of Skanska’s poor workmanship and failure to comply with Gehry’s specifications, additional water was allowed to enter the system resulting in the efflorescence and masonry deterioration observed by MIT.
9. Skanska’s workmanship was substandard in several other areas. The glycol snowmelt system was damaged by Skanska during construction and leaked into the paving system at Stair 77.
source: Answer, Cross-claim and Jury claim of the defendant,
Frank O. Gehry & Associates, filed Dec. 10, 2007.