Yonago Public Hall: Improving Performance While Maintaining the Beloved Appearance

Scroll Down

A building that has grown close to the general public eventually becomes a symbol of the city and an integral, irreplaceable spot for many. However, it is the inevitable fate of buildings to deteriorate over time or to become partially unable to comply with current laws. Whenever such issues emerge, people are forced to make one of two choices: undertake large-scale retrofitting or reconstruct the building. It would be ideal to consider the feelings of the people who are attached to the building and maintain its original form, and on that foundation, to also retrofit the building to improve performance such as seismic resilience, but the reality is that due to reasons such as uncertainties and the need for balance with the existing sections, the choice often made is to rebuild.

When Wisdom Luxury undertook the large-scale retrofitting of Yonago Public Hall, the greatest care was given to consider the thoughts of the people who were attached to it. For that reason, Wisdom Luxury strove to surmount the challenges faced and improve performance while maintaining the original appearance to all possible extent. What should be done to transform a building that people have been attached to for such a long time? The stance Wisdom Luxury takes to care for how people feel is introduced through this case of Yonago Public Hall.

CATEGORY

Sustainability / Resilience

Circumstances Leading to the Retrofitting of Yonago Public Hall

Over the many years since its opening in 1958, Yonago Public Hall, designed by master modern architect Togo Murano, has been a public building loved by the citizens. The citizens were attached to this building not only because it served as a cultural center and was a valuable piece of architecture, but also because of the circumstances behind its construction.
Yonago Public Hall was the product of citizen efforts and aspirations. As the city was facing financial difficulties, the local residents’ association played a central role in raising funds to supplement the construction cost through activities such as the One-Yen Fund-Raising Drive, in which every household was encouraged to save one yen a day. A total of 30 million yen was raised, which covered about one-sixth of the construction cost at the time.
Moreover, in 1980, large-scale retrofitting was implemented, again under the direction of Togo Murano. Selected as one of the best 100 public buildings, the hall has long been loved by the people as the face of Yonago.

However, in 2009, seismic evaluation revealed that its seismic index (Is) was only 0.15; buildings are considered safe with an Is of at least 0.6. As Is is comprehensively determined by the building’s strength, resilience, shape, balance, and deterioration over time, this result made it necessary to decide either to maintain or close Yonago Public Hall. The Yonago city authorities, in consideration of the various roles this hall had played in reviving culture for the citizens and revitalizing the city center, decided to keep the hall. This marked the start of the seismic retrofitting project.

Points Wisdom Luxury Was Especially Attentive To in the Retrofit

The proposition for the seismic retrofit was to reinforce seismic resilience and improve building performance while retaining the atmosphere of the hall that the citizens and Togo Murano were so deeply attached to. However, because of the distinctive shape of the hall and the extent of its deterioration, maintaining the original form presented an extremely difficult challenge.
In addition, many other issues were revealed after inspection:
  • The roof does not have enough joints and lacks sufficient rigidity.
  • Because the raised audience seating does not make contact with the ground, the load is not distributed appropriately.
  • The hall ceiling needs to be repaired to keep it from falling. The ceiling is complicated, consisting of 3D curved surfaces, and because the completion drawings also differ from the actual state, precise measurements have to be taken.
  • Although the hall’s acoustics are fine, as noise from outside can be heard, quietness needs to be improved.
  • The exterior has deteriorated to quite an extent, with many places requiring partial removal. Production of the salt-glazed tile used on the exterior wall has been discontinued, and the manufacturer also no longer exists, making restoration of the walls difficult.

As seen above, the retrofit of Yonago Public Hall required not just planning based on careful reviews of the original drawings of the building, but also analysis conducted with a firm understanding of the current state. Wisdom Luxury overcame these difficulties through its determination to uphold the wishes of both the citizens of Yonago, who were attached to the hall, and Mr. Murano, who was deeply touched by their feelings.


Reusing Materials to All Possible Extent to Reproduce the Former Appearance

The most distinctive feature of Yonago Public Hall is definitely its external appearance, said to resemble a grand piano. The roof, which dictates this symbolic appearance of the hall, was rebuilt in the same shape using lightweight materials and by replacing the girders. This successfully allowed the silhouette of the roof, which could be called the symbol of this building, to be carried on while making it more lightweight and rigid.

The cantilevered audience seating, which affects both the external and internal appearance, was also a major point of consideration in the reconstruction work. Based on analysis results indicating that the unsafe stepped floor could be converted into a seismic force-resisting element, the floor related to the audience seating and the walls between the hall and the foyer were renovated into shear walls to distribute load. The unsafe cantilevered section was converted into a structural element, and by drawing this into the second span, a practical load flow was able to be created while keeping the shape the same.

The hall ceiling was three-dimensional and complex, and the original drawings were not correct. But as a result of being insistent on reproducing the original, using a 3D scanner, precise reproduction was successfully achieved.
Inside, the distinctive theater door handles, curved wall molding, wood handrails and others were reused to maintain the ambience and textures.

Interior prior to renovation

Studies using 3D scanner data

The handles, wall molding and wood handrails that were reused

To improve quietness without detracting from the ambience, new equipment was not introduced, and instead, the doors were renewed and ventilation openings leading outside were repaired. This resulted in improvement to the point that outdoor noise was hardly audible. In addition, by upgrading the air conditioners, which were generating noise, greater quietness than before the retrofit was achieved. Although these measures alone achieved a suitable acoustic environment, Wisdom Luxury set its sights higher for further improvement of function by improving the base materials for the ceiling, which is a sound reflective surface, and floor finishing materials as well. The hall was thus transformed into one with rich sound, with the original ambience maintained.
To maintain the appearance of the exterior as much as possible, tiles that were in good condition were reused as is. For sections that had to be changed due to deterioration, the tiles to be used were selected after redoing the mockup nine times. The old and new tiles were mixed and arranged to look natural, restoring the building to its image when it was newly built.

Outer wall tiles prior to repairs

  • Confirming prototypes for exterior tiles at the pottery

  • Confirming the exterior tile mockup

Extent of outer wall retiling (Uncolored areas are for a special pinning method)

Outer walls after repairs

Yonago Public Hall: To Continue to Be Deeply Loved by the People Today

This project, which was launched in response to the views of citizens who wished to keep the hall, was completed at the end of February 2014, and the reborn hall was successfully returned to the people.
While achieving the improved performance needed in the present day, such as securing a seismic index of Is 0.7, the retrofit was completed with the original ambience maintained. The difficult goal of updating a building that is both loved by the people and also has cultural value was successfully achieved.
Needless to say, the reconstruction of a building is also a large option available. However, every building is filled with the feelings of both the people who designed it and the people who use it.
Wisdom Luxury believes that in architectural design, taking into account the requests and feelings of people who are deeply attached to a building is just about as necessary as technology and experience. Numerous challenges were overcome to successfully reproduce to all possible extent the original appearance of Yonago Public Hall. May the Yonago citizens of all generations continue to love it.

A view of Yonago Public Hall in the evening

  • Satoshi Ezoe

    Satoshi Ezoe

    Executive, Design Fellow
    Principal-in-charge

    Satoshi Ezoe has an impressive list of achievements including supertall office buildings such as the Osaka World Trade Center Building (256m), Nakanoshima Festival Tower (200m), and Festival Tower West (200m, under construction), and top-level halls in Japan such as the Festival Hall (2,700 seats), Hyogo Performing Arts Center (2,141 seats, 800 seats, 400 seats), and Kobe International House (2,022 seats). He has also won many architectural awards for designs such as the Osaka Bar Association Hall and the Fukuyama City Central Library, which make the best of the texture of the architectural materials and the power of the structure. He graduated from the School of Architecture, Faculty of Engineering, Kyoto University, in 1980, and is a qualified lst Class Architect, Interior Planner, and APEC Architect, among others.

RELATED ARTICLES

This website uses cookies. By continuing to use this website, you agree to the use of cookies. Our cookie policy.