Project Specifics

Zocalo Community Development and Hines, developers of two adjacent sites in the booming real estate market of Denver’s Central Platte Valley, required a full design review for a 43 ft deep excavation for Hines’ new site at 1601 Wewatta. The 1601 Wewatta site is immediately adjacent to the recently constructed Cadence Apartments site, a 13-story mixed commercial and residential structure developed by Zocalo.

Geosyntec Scope of Services

Geosyntec was the specialty geotechnical engineering consultant for this risk assessment work on behalf of the two parties. The scope of work included a design and constructability review for a 43 ft deep support of excavation (SOE) system immediately adjacent to an existing high-rise mixed residential/commercial structure. The SOE consisted of a stiff secant pile wall supported by steel wales and temporary tieback anchors. The secant pile wall also performed as the support system for exterior columns and a settlement-sensitive building façade. Geosyntec performed geotechnical and structural analyses to verify the design of a local structural engineer for the SOE, with the most important objective of characterizing the likely response of the adjacent Cadence Apartments structure during the course of the excavation. Within a limited timeframe, we developed predictions of SOE three-dimensional movements and their impact on the adjacent drilled-shaft supported structure, including working with the Cadence Apartments structural engineer to evaluate the directional stiffness afforded by restrained columns, transitions to drilled shafts, and internal slabs acting as diaphragms.

Geosyntec also contributed to the development of a detailed instrumentation and monitoring plan with involvement of six other parties including financiers and insurers. We provided construction consulting services to Hines, Zocalo, and general contractor Whiting-Turner during SOE installation, excavation, and sequenced construction of the below-grade parking structures. Following successful completion of the project, Geosyntec provided additional assistance to Whiting-Turner related to a significant construction claim emanating from the tieback installation for the secant pile wall.

Notable Accomplishments

Geosyntec was a critical member and contributor to the success of this project, including protecting the interests of two separate real estate developers sharing a property line and significant risks. We provided technical contributions to the construction process that reduced risks to the major parties including the developers, contractors, financiers, and surety stakeholders.

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