Japan Architectural Review最新文献

Japan faces the serious challenge of a decreasing and aging population, impacting the maintenance and upgrade of public libraries. Concurrently, public libraries, crucial social education facilities in Japan, are expected to assume broader societal roles. In response, some Japanese public libraries relocated to address these challenges and new demands. However, there has been limited research focusing on the relocation process and its subsequent evaluation. This paper fills this gap by concentrating on relocated public libraries (RPLs) in Japan during the recent decade (2010–2020), aiming to investigate their relocation motivations and spatial improvement and evaluate their role fulfillment after relocation. By posting questionnaire sheets to 217 target RPLs, we collected 143 valid responses, did a cross-analysis on motivations, spatial changes, and library types, and evaluated improved role fulfillment postrelocation. Results suggest that public libraries are serving multiple roles in their communities, and their role fulfillment after relocation was linked to certain locational and spatial improvements. This research could help upgrade and reorganize public libraries in the future and contribute to the literature by understanding the relocation of public libraries from a dynamic perspective.

This study aims to reveal the difficulty of realizing large hyperbolic paraboloid (HP) shell structures comprising reinforced concrete in earthquake-prone Japan in the 1950s. The analysis focused on the design and construction of Sunpu Kaikan, focusing on the roles of Kenzo Tange and Yoshikatsu Tsuboi, alongside their architectural laboratory staff. It revealed how the experience gained in the Sunpu Kaikan project contributed to two architectural projects in the 1960s: the Niigata City Gymnasium, with its steel-frame concrete HP shell, and the Yoyogi National Stadium, with its suspension roof structure.

In aging and aged countries, one of the main issues is to establish sufficient nursing homes for seniors. Japan, as one of the most rapidly aged countries, has been reforming nursing homes for the elderly since the 1990s and established a long-term care insurance system. The purpose of this scoping review is to systematically map the evolution of researches for nursing homes in Japan since the 1990s, particularly with the post-occupancy evaluation of the introduction of private rooms and small units. Forty-three articles concerning privatization of rooms, shared spaces, and small unitization in nursing homes were extracted and analyzed. They were published between 1994 and 2021 in Journal of Architecture and Planning, AIJ Journal of Technology, JAABE, and JAR. The results revealed an evaluation of the privatized rooms mainly from the perspectives of residents' lives and care staffing, the effects and issues of the shared spaces introduced at the same time as private rooms, and the evaluation and issues on subsequent unit-type floor plans. This study offers significant implications to Asian countries that will have aging and aged populations in the near future by summarizing Japan's experience in dealing with realistic and practical problems over the past 20 years.

In recent years, there has been an increasing demand for small-scale hostels, such as vacation rentals, known as “minpaku” in Japanese, which were originally single-family houses. To convert these buildings for use as accommodation facilities, improvements must be made to fire evacuation safety measures. An effective and reasonable measure for this improvement is the installation of wireless, interconnected alarm smoke detectors. We conducted experiments to examine how sleeping guests recognize these alarms when they are activated. Eleven participants experienced the alarm sounding while sleeping at night and while awake during the daytime at a wooden cottage. They were exposed to three different sounding patterns. In the sleeping experiment, 9 of 11 participants were woken up by alarms sounding in other rooms, while the remaining two were woken up by alarms in their own rooms. However, those two participants had difficulty understanding the meaning of the voice alarm clearly. The voice stated, “Other detector was activated,” indicating a fire in another room and urging evacuation, even though there was no smoke in their room. Comprehension of the alarm system is essential for guests to understand its intentions accurately and make proper decisions regarding evacuation.

This research conducted investigations of buildings equipped with radiant systems and expert interviews in 2021–2022 with manufacturers and mechanical, electrical, and plumbing (MEP) engineers in Japan who had experience designing radiant heating and cooling systems for non-residential buildings. In total, interviews were conducted with 56 respondents from 16 companies. Results from the building investigation showed that 69% of the identified buildings had radiant ceilings, and 30% had radiant floors. In terms of working fluid, 56% were water-based, and 43% were air-based. For the expert interview, 79% of all respondents answered that the use of radiant systems will continue to increase in the future. In total, 54% of all respondents answered that it has become easier to design radiant systems at present compared to the 2010s. Based on the results, knowledge gaps and challenges in the design of radiant systems were summarized in terms of design method, room temperature control, auxiliary systems, and their relevance to building decarbonization.

Short-period ground motions from earthquakes are calculated by semiempirical methods such as the empirical Green's function method or the stochastic Green's function method. In this review paper, I summarized source models developed for reproducing and predicting ground motions in the theoretical methods at first, and then reviewed the source models applied to reproducing and predicting ground motions in the empirical Green's function method in these about 40 years. Finally, I showed some issues to be solved about source modeling in order to predict accurate short-period motions in the near-fault regions.

The response spectrum method (RSM), specified by the Ministry of Construction notification Vol. 2009, is not part of the countermeasure to address the Nankai trough long-period and long-duration ground motions (LPGMs) announced in 2016. Consequently, in this study, an approach was proposed to assess the effect of changes in characteristics due to repeated deformations using the RSM for LPGMs and seismically isolated buildings using lead rubber bearings (LRBs). However, this study identified potential areas for improvement in the calculation of effective damping using the RSM. An effective damping calculation method of the RSM using an effective ductility factor is introduced to enhance the accuracy of the proposed method. The proposed RSM-based method was verified against the methods based on nonlinear time history analysis. The earthquake response prediction results using the proposed method were compared with those of not only the simplified method but also the precise and the quasi-precise methods. The accuracy of earthquake response prediction using the proposed approach is increased by 30%–50% when the effective ductility factor is used to compute the effective damping. Therefore, earthquake response can be predicted using the proposed method, and the accuracy achieved is similar to the nonlinear time history analysis.

Aiming to improve thermal environment for outdoor public spaces, the author had been developing a unit-type green parklet for parking lots that both introduce greenery into cities and produce walkable urban spaces. In this study, the author examined and created a full-size unit-type green parklet, installed it in a parking lot adjacent to sidewalk space next to a bus stop in the traditional urban area, Kyomachi district, of Kumamoto City, and investigated the improvement to summer thermal environment from a field measurement and its usage by people from user survey in summer (from August 30 to September 5, 2022). The results showed that although the parklet shaded with the parasol and greening units, air temperature dropped by only a maximum of 1°C in daytime. Given the characteristics of parking lot as a location, it was confirmed that not only the wind and airflow conditions was blocked and worsened, but reflected solar radiation from the surroundings and generated heat from parked cars degraded air temperature and MRT from the field measurement. Furthermore, it was confirmed to be ensured the visibility of the surroundings when sitting on the parklet bench for the users waiting for a bus from user survey.

In recent years, there has been concern about the occurrence of extreme ground motions that greatly exceed the amplitude levels and durations expected at the conventional design level. Therefore, seismically isolated buildings are required to ensure seismic isolation performance for small earthquakes and suppress the excessive displacement of the seismic isolation layer for extreme ground motions. In this paper, we analyze the seismic response of seismically isolated buildings with the dead zone mechanism connected to oil dampers to understand the response characteristics.

This study analyzed the mechanism of shopping difficulties for low-income groups in central Tokyo, where economic disparity is progressing due to gentrification. Through questionnaire and interview surveys, as well as analysis of time-series environmental changes, we found that since 2000, shopping difficulties have been induced by the decline of shopping streets and the upgrading of supermarkets in parallel. Furthermore, in the areas where the percentage of high-income groups due to redevelopments has significantly increased, luxury supermarkets opened at the same time as the construction of luxury condominiums, making it difficult for affordable supermarkets to locate.