Japan Architectural Review最新文献

Super-high-rise buildings commonly utilize tuned mass dampers (TMDs) for vibration control. However, buildings with different natural periods in two horizontal directions typically require multiple TMDs, increasing weight, and costs. In this study, a bidirectional TMD (BTMD) was developed to control vibrations simultaneously in both horizontal directions of high-rise buildings with different natural periods by independently tuning natural frequencies in both directions through rotational swing and orthogonal linear oscillation of the mass component. Numerical analyses and shaking table experiments on reduced-scale building models confirmed its effectiveness in suppressing structural responses of peak and root-mean-square acceleration and displacement. The proposed BTMD offers a cost-effective and lightweight solution for enhancing the seismic resilience of high-rise buildings with different dynamic properties in two directions.

This study examines the characteristics of social interactions in public spaces within Nairobi's informal settlements, with a focus on Mukuru Kwa Njenga. In the absence of formal planning and infrastructure, road spaces—particularly residential streets and a main thoroughfare—function as the primary venues for daily interaction, economic activity, and community life. Based on field observations, structured questionnaires (70 groups, 189 individuals), and pedestrian count data, the study analyzes interaction patterns across five dimensions: group scale, spatial proximity, nature of neighborhood relationships, degree of social mixture, and level of economic activity. The findings reveal that residential streets foster diverse, cross-cutting interactions among residents of varying gender, ethnicity, religion, and origin, while the main street is characterized by more homogeneous, identity-based groupings, often tied to shared origin or kinship. This contrast reflects underlying residential patterns and economic functions. By highlighting the differentiated roles of public spaces in socially complex environments, the study contributes to a deeper understanding of how informal communities negotiate coexistence. It argues that acknowledging these spatial–social dynamics is essential for inclusive upgrading strategies and the design of shared urban spaces in informal settlements.

Weather data plays a critical role in the accuracy of Building Performance Simulations (BPS). The temporal resolution of weather data can influence the outcomes of simulation-based design and operational decisions. This study examines the impact of weather data temporal resolution on building energy and daylighting simulations. EnergyPlus is employed as the BPS engine to compare the effects of different temporal resolutions, hourly, 5-min, and 1-min weather data, on simulation accuracy, and to contrast simulation outcomes using high-resolution weather data with conventional hourly data. The results show that the resolution of weather input data has only a slight impact on annual energy consumption for heating, cooling, and lighting. However, significant discrepancies emerge at the daily level, especially during periods of rapidly changing sky conditions. The study highlights the value of high-resolution weather data for performance modeling in buildings that use responsive shading or window control systems. Most notably, on partly cloudy days, shading control performance differed by approximately 8% when comparing simulations using 1-h weather data to 5-min or 1-min data. This indicates that hourly data fails to capture rapid fluctuations in solar radiation under variable sky conditions. For applications involving dynamic controls, finer temporal resolution is essential for reliable simulation.

Continuous beam-type connections between concrete-filled steel tube columns and I-section steel beams have a disadvantage in that the area of the openings for concrete filling decreases because of the existence of continuous beams. To resolve this issue, perforations were made in the beam flanges within the connection panel to improve the concrete filling. To investigate the structural performance of continuous beam-type circular concrete-filled steel tubular beam-to-column connections with perforations in the connection panel, an experimental study was conducted using T-shaped sub-assemblage specimens. The experimental parameters considered were the presence of perforations in the flange within the connection panel and beam-fixing types. All specimens exhibited a beam-yielding failure mechanism, characterized by large hysteresis loops and a high energy absorption capacity. For the specimens with perforations in the beam flange within the connection panel, strain concentrations were observed near the perforations when a tensile force was applied to the beam flange. However, no deterioration in the hysteretic behavior owing to this factor was observed. In addition, a finite element analysis was conducted. The stress transfer mechanism within the connection panel was examined based on the results of the analyses.

This project is based on the hypothesis that the combination of visual information and environmental grades—such as airflow and temperature—in a uniform, sequential space can influence psychological responses. To explore this hypothesis, we selected the Kiyotsu Gorge Tunnel as a case study. This tunnel provides a controlled spatial environment with limited external visual stimuli and includes four viewing decks that open to the outside, allowing natural light, air, and temperature variation to enter the interior. The renovation was intended to couple visual stimuli with airflow variation, under the hypothesis that this co-variation may strengthen psychological responses. Architectural elements, including water ponds and reflective mirrors, were introduced to enhance airflow or reflection from the exterior and intensify sensory engagement. Through this combination of visual and environmental cues, the project sought to create a cohesive, immersive experience throughout the entire tunnel.

After the 2011 earthquake and nuclear accident in Japan, most residents near the powerplant evacuated, but some are now returning after decontamination. Odaka, a town ruined by this disaster, has fewer buildings now than before the disaster. The transformation that vacant lots undergo after the demolition of buildings is influenced by the structure of the town center. Since the lifting of the evacuation order, there have been efforts to use vacant lots as gardens. In addition, lots owned by absentee landowners are weeded by community associations, weeding companies, and volunteers. Residents have expanded the scope of maintenance to vacant lots that they do not own in response to changes in the town's physical environment.

The construction of building foundations requires substantial time and effort, particularly in fabricating reinforced concrete footings and foundation beams. To address these challenges, this paper proposes a novel structural system that utilizes steel structures for the foundation beams and reinforces pile heads with double steel tubes. Loading tests were conducted to assess the influence of various factors. The applicability of existing evaluation equations is examined to highlight the need for a new prediction formula. As a result, this paper proposes an evaluation equation for the ultimate bearing capacity and a constitutive law to predict the behavior under compression forces.

This paper proposes a modeling approach for the restoring force characteristics of unbonded precast prestressed concrete (PCaPC) beams with widened beam ends. Two models are introduced: one uses rotational springs at the outer ends of the general and widened beam zones, while the other uses a single rotational spring with an equivalent rigid zone. To validate the models, ten unbonded PCaPC beams with varying parameters, such as the amount of longitudinal rebar, the size of the widened beam ends, and the level of prestressing force, were constructed and tested. The proposed models demonstrated good accuracy in capturing the restoring force characteristics observed in the experimental results.

More than a year has passed since COVID-19 has been classified as a Class 5 infectious disease in Japan. However, in elderly inpatient facilities, where residents are at high risk of developing severe symptoms, there remains a strong need to prevent mass infections. This study aimed to obtain information on the prevention of the spread of COVID-19. First, I clarify the occurrence of COVID-19 cases in elderly inpatient facilities and then consider the spread of positive cases from a spatial perspective.

There is a widely held belief that the closure of primary schools has a negative impact on the surrounding communities. To verify this hypothesis, this study investigates the relationship between primary school closure and local populations in Japan. Specifically, we compared the rates of population change before and after 5 or 10 years of school consolidations in a regional core city and found that, in 70% to 80% of school closures, there was no acceleration of the local population decline after the consolidations. The results before and after 10 years and before and after 5 years are nearly identical.