Keio University Hiyoshi Campus Fourth Building, Independence Wing

Location

4-1-1

Yokohama, Kanagawa Prefecture

Japan

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Certifications & Awards
  • CASBEE rank "S"
Project Team
  • Designer: KAJIMA DESIGN
  • Owner: Keio University
  • Contractor: Kajima Corporation Yokohama Office

Summary

Housing classrooms, this structure was rebuilt as part of Keio University’s 150th anniversary celebrations. The design brief emphasized two key points—the facilities would cater to some 10,000 students at peak times and should serve the university for at least 50 years. Hence, the design has a straightforward structural presence. A gentle approach lined with cherry blossom trees links campus to town; the large roof and louvers facing the approach avenue connect building and environs; while students pass to and fro through the approach junction and atrium. The interior and exterior common spaces incorporate systems that utilize natural energy sources and capitalize on the site’s approximately 9m difference in elevation between lowest and highest points to provide a diverse space for students. The combination of atrium, rooftop courtyard and innovative classroom layout protects the 35 large and small learning spaces from noise and afternoon sun, providing a constant flow of fresh air through the atrium to the classrooms. Removal of an 8m-high concrete retaining wall from above the adjoining main road and resultant 180m-long open space is a scenic plus for the town. By incorporating concrete and other materials from the previous building in the external cladding, a new relationship with the building’s surroundings was built on traces of the past.

Q-1 Indoor Environment

  • Noise criteria (NC) level of 25-30
  • Classroom sash sound insulation performance of class T-2
  • Large lecture theater wall sound insulation performance of TLD-56 (D-45)
  • Classroom floor sound insulation performance of L-55
  • Majority of classrooms achieve a daylight factor of 3.0 or higher
  • Installation of effective skylights as a means of increasing daylight usage
  • Daylight control through the use of eaves and blinds
  • Achieves lighting intensity of 750 lux or higher
  • Used construction materials with low VOC discharge
  • External air inlet volume 25m3 / person / hour
  • No smoking allowed inside the building

 

Q-2 Quality of Service

  • Complies with the Heart Building Law
  • Classroom ceiling height of 3.2m-3.95m
  • A space with a diverse array of features that encourages communication
  • Aseismic performance that exceeds the legally mandated level by 50%
  • Utilizes seismic isolation system
  • Architectural precast concrete panels faced with porcelain tiles
  • 30-year interval between renewals
  • Air conditioning systems in high-priority rooms have autonomous ducting to external units
  • A facilities plan that follows the seismic isolation system
  • Measures undertaken to reduce risk of electrical room flooding
  • Each floor has a height of 4.0m or over
  • Rack ES full-surface inspection flaps and underfloor cable routing for office automation (OA) equipment
  • Telecommunication cable routing may be reconfigured without causing damage to structural members or finishing materials

 

Q-3 Outdoor Environment on Site

  • Understanding of the site's vegetation and biological environment
  • Creation of cherry blossom and zelkova tree-lined avenues and other continuous green spaces to enhance amenity value for strolling
  • Reuse of site's existing topsoil
  • Provision of habitat for birds
  • Over 60% of external area made into green space
  • Building green space rating of 0.06
  • Provision of green roadside space for the enjoyment of pedestrians
  • Provision of intermediary spaces linking building interior with the outside (approach avenue, etc.)
  • Plan to enhance line of sight by demolishing an existing concrete retaining wall
  • Indoor-outdoor connecting space provides a pathway for the wind
  • Provision of shade from the sun and green areas and the use of water-retentive pavement material contribute to improvement in the site's thermal environment

 

LR-1 Energy

  • Use of low-E glass; PAL value of 272.3
  • Atrium skylight facilitates natural lighting / air flow / ventilation system
  • Reduction of outdoor air thermal load through the use of total heat exchanger
  • Cool tube utilizing seismic isolation level
  • Adoption of an air conditioning operational-data management system that is able to conduct a range of measurements of energy conservation performance

 

LR-2 Resources and Materials

  • Measures to conserve water, including automatic faucets, water-saving faucets and user sensor systems
  • Use of rainwater to supply water for toilets and urinals
  • Use of electric furnace steel in main structure; use of Portland blast furnace cement in some parts of main structure
  • Use of recycled lumber in roof garden floor deck
  • Use of construction materials that do not contain hazardous substances
  • Reuse of concrete structure of previous building in exterior design
  • Non-use of halon fire extinguishing agents
  • Use of insulation materials which have ratings of ODP=0 and GWP=0

 

LR-3 Off-site Environment

  • Measures to prevent light pollution
  • No advertising signs
  • Wind environment simulations used to reduce impact on surrounding environs
  • Waste disposal burden reduced through such measures as separation of waste and separate collections for each category; paper recycling; reduction of bottle and can volumes