Developer/Owner

Irongate AZREP BW LLC

Architect

Benjamin Woo Architects LLC & Guerin Glass Architects

Contractor

Kobayashi Kiewit Joint Venture

Location

Honolulu, Hawaii

Background

This project is the flagship property of the $535 million Waikiki Beachwalk redevelopment project. BASE provided structural engineering services on a new 350 ft. luxury tower featuring 14 residential floors, 15 condotel floors and spa and recreation deck levels including an infinity-edge feature pool above five levels of parking.

Client Benefits

The design resulted in a very efficient structure requiring only 6.1 pounds per square foot of reinforcing steel and 0.56 pounds per square foot of post-tension tendons. When compared to the average reinforcing steel rates of six other recent Hawaii high-rises of 8.0 pounds per square foot reinforcing steel and 0.70 of post–tension tendons, the equivalent savings to the client by this efficiency is estimated at over $2 million.

The Science and Design of Structural Engineering

The project constraints included squeezing 39 floors into a mandated height limitation of only 350 ft. In order to accomplish this, several parking levels needed to be 8 feet floor to floor and hotel levels needed to be 8 feet 6 inches floor to floor. The height constraints were achieved with thin slab post-tensioned technology coupled with 3D analysis to verify performance. The final design allowed 6-inch-thick slabs through a majority of the structure. Height restrictions also posed challenges for the structure's lateral load resisting system. The project incorporated innovative steel plate reinforced link beams to achieve the required strength and stiffness of the building.