Construction Option

Hotel - Sunnyvale Plaza

United States

This is a student-generated Capstone Project E-Portfolio (CPEP) produced in conjunction with the AE Senior Thesis E-Studio

 

Construction Start: July 2011

Estimated Construction Completion: May 2014

Project Delivery Method: Design Build / GMP

 

Architecture:

The Sunnyvale Plaza is a 752,000 square foot high-rise hotel surrounded by a dense city within the Eastern United States. Consisting of several ballrooms and restaurants, the hotel will be able to support guests for the 11 stories of suites. The below-grade floors will include parking garage space and a concourse to the convention center next door. The hotel is also constructed on the same lot as two existing buildings in opposite corners. This creates a challenge of implementing one of the buildings into the new structure and avoiding disruption of the other.

 

The Sunnyvale Plaza is a 22 story structure with 11 floors for guest rooms and 7 floors below grade. A small existing building on the corner of the lot is implemented into the construction of the new building. The hotel consists of 1,175 guest-rooms, 87 meeting rooms, and 49 suites. The first floors of the hotel also include five restaurants. A 30,000 square foot grand ballroom and two 10,800 square foot junior ballrooms are located just below the first level, followed by a multi-level parking garage for valet parking services. The center of the structure features an open atrium through all 15 above-grade stories and a statue piece. Within the garage, a concourse passageway was added to enter the neighboring parking garage. This concourse created complications with protecting the street and mechanical pipes overhead.

 

Major National Model Code:

  Major Model Code that pertains to the project include:

  2000 International Building Code with local amendments

  2000 International Fire Code with local amendments

  2000 International Plumbing Code with local amendments

  2000 International Mechanical Code with local amendments

  ADA accessibility guidelines

  NFPA 12 – Automatic Sprinkler Systems, 1996 Edition

  NFPA 72 – Fire Alarm Code, 1996 Edition

  NFPA 70 – National Electric Code, 1996 Edition

  NFPA 20 – Fire Pumps, 1996 Edition

 

Historical Requirements:

The only restrictions for the site are the connections to the existing buildings within and nearby the site. A convention center on the adjacent site is connected through an underground concourse, and the existing historical structure on-site was required to be implemented into the new hotel design.

 

Zoning Influences:

There were three major zoning influences that were necessary for the design of the hotel. There was a 224’-9” height restriction above sea level. Compartmentalization was also required below grade and implemented post 95% design completion. Finally, as described previously, the neighboring structures were incorporated into the design of the building.

 

Building Enclosure:

Building Façade:

The underground garage exterior utilizes a slurry wall construction, which is not very common within the area. The slurry wall was considered the most economical way to construct and excavate the underground portion of the structure. Above ground, the façade consists of metal and glass panels utilizing a curtain wall construction. This curtain wall consists of 2,400 wall units and 29,000 punched window units. Storefront glass, steel sunshades, and glass cable walls also make up portions of the curtain wall.

 

Building Roof:

The primary roof consists of a glass skylight, about the size of a football field, to allow light into the atrium. A majority of the overall roof consists of this glass covering. Around the skylight are several roof pieces at varying levels. Lower roof pieces located at the top of the existing structure and across the front edge of the building are utilized for rooftop terraces and picnic areas. The roof, in whole, consists of 5,200 square feet of rooftop terrace overlooking the city center.

 

Sustainability Features:

The project team is pursuing a LEED Silver certification with a total of 36 expected points for Sunnyvale Plaza. There are also 5 extra points that are a possibility, which would be enough to earn LEED Gold certification. The hotel will be one of the largest hotels in the United States to earn a LEED certification. LEED credits being pursued include Alternative Transportation, Water Efficient Landscaping, Storm-water Design, Heat Island Effect, Construction Waste Management, Low-Emitting Materials, and Innovation in Design.

 

Excavation Process:

Sunnyvale Plaza required a very unique excavation process. Due to the extensive depth of the hotel, typical excavation practices would not be possible. The project team utilized a top-down excavation process in which each below-grade slab was poured on-grade then excavated from underneath. Several areas were left open through each slab to allow for cranes and larger equipment to transport the excavated material out of the site. The slurry wall acted as the exterior shoring during construction. This excavation process, although necessary, was very lengthy and required an entire year more than typical excavation processes.

 

Structural System:

Sunnyvale Plaza contains a very unique structural system that began during the excavation process. The below-grade structural system consists of steel columns encased in concrete with typical reinforcement. A slurry wall also extends around the entire substructure, up to 115' below-grade. The slurry wall consisted of 4,000 psi normal weight concrete. Every below-grade slab was poured on-grade and excavated underneath. Slabs consist of typical composite metal decking and normal weight concrete. the concourse construction creates the need for temporary steel columns while excavating through each slurry wall. The underground utilities also needed to be temporarily supported during construction. The superstructure consists of precast concrete beams and columns with typical reinforcing bars. Steel columns typically ranged from W14x90 to W14x342 with two W14x665 columns. Concrete columns and beams ranged in size from 12x12 to 50x66.

 

Electrical System:

Sunnyvale Plaza utilizes a 460/265 electrical distribution system which is provided by The Potomac Electrical Power Company. The hotel consists of nine 460/265 Volt, 4,000 Amp switchboards that turn down to 208 Volt, 400 Amp panelboards. Panelboards are located within the three electrical room on each of the above-grade levels. Electrical rooms are located near each corner primary corner of the building near the elevator lobbies. The emergency power panelboards are located on the below-grade levels. The emergency power runs vertically up the entire tower and branches around each floor.

 

Mechanical System:

The mechanical system for Sunnyvale Plaza consists of a variable air volume system. Six cooling towers are located on the roof of the hotel while several air handling units are located on the first floor, third floor, and all below-grade levels. The above-grade mechanical rooms are located near each corner of the building. These rooms are typically electrical rooms on other floors. Each guestroom consists of a fan coil unit to control and condition the room separately. Electric heating coils are utilized for heating of the hotel. The atrium skylight is expected to provide a substantial amount of direct sunlight heat throughout the year which will most directly translate to the lobby and restaurants.

 

Fire Protection:

The fire protection system consists of pressurized stairways throughout the entire structure. Typical sprinklers and fire dampers were utilized within the plumbing and mechanical system. A two hour fire rating was required on most assemblies.

 

Transportation:

Sunnyvale Plaza consists of 13 elevators in groups of four or five in each primary corner of the building. Two escalators are also utilized for traffic through the concourse to the neighboring convention center.