Search Results (73)

Super high-rise buildings are increasingly equipped with structural monitoring systems to track deformation responses during construction and operation, thereby supporting structural condition assessment and engineering management. To address key monitoring challenges, including GNSS multipath interference, insufficient vertical accuracy, accelerometer integration drift, and high-frequency noise, this study proposes a GNSS/accelerometer fusion monitoring method based on whale optimization algorithm–optimized variational mode decomposition (WOA-VMD) and adaptive robust Kalman filtering (ARKF). Continuous three-hour GNSS and accelerometer observations collected from a super high-rise building under construction are used for fusion validation. The results show that WOA-VMD effectively separates noise from deformation-related signals and outperforms conventional EMD and standard VMD in denoising performance. Compared with the raw observations, the fused east, north, and vertical displacement RMSEs are reduced by 68.84%, 75.97%, and 60.22%, respectively; the SNRs increase to 22.03 dB, 21.38 dB, and 16.74 dB, respectively; the STDs decrease by 72.58%, 75.62%, and 68.39%, respectively; and the PSDs increase to 9.47 dB, 9.02 dB, and 8.31 dB, respectively. The proposed framework exhibits sub-centimeter-level displacement monitoring performance in the horizontal directions and significantly enhances the monitoring capability of the vertical component. The field validation results demonstrate the feasibility and effectiveness of the proposed framework for short-term deformation monitoring of super high-rise buildings under practical monitoring conditions and indicate its potential for structural health monitoring applications. Full article

The influence of debonding in concrete-filled steel tube (CFST) columns on the dynamic characteristics of super high-rise buildings is a common concern that remains insufficiently understood. The abnormal vibration incident of the SEG Plaza on 18 May 2021, also known as the 5·18 incident, serves as a typical case highlighting this issue. After two decades of service, the first-order bending frequency of the building decreased by approximately 6.1%, and extensive CFST column debonding was observed, with the maximum debonding rate reaching up to 97% on certain middle floors. To investigate the influence of CFST column debonding on structural dynamic characteristics, this study first derives a theoretical relationship between debonding parameters, namely angle and distance, and the equivalent bending stiffness of CFST columns. This analytical formulation is then implemented and validated through finite element simulations at multiple scales, including planar frame analysis in ABAQUS, a thin-interlayer simulation method in ANSYS, and full-building modeling in ETABS. Results show that for a planar frame, when a CFST column debonds at 270°, the structural natural frequency decreases by 0.984%; when the debonding angle is 180° with a 2 mm gap, the first-order frequency decreases by 0.141%. Numerical simulation of the SEG Plaza structural model predicts a reduction in the first-order frequency of 0.987% under the observed debonding conditions, confirming that debonding impairs force transmission, reduces structural stiffness, and alters natural frequencies. This study provides a mechanistic basis for evaluating stiffness degradation in long-service super high-rise buildings. Full article

Cities in climatic transition zones face coupled radiative and evaporative stresses, and their carbon emission mechanisms differ significantly from those in humid regions. Taking Xi’an, a typical megacity in the transition zone, as a case study, this research utilises a 500 m × 500 m grid to integrate multi-source data for carbon emission accounting. By applying spatial autocorrelation and the Multi-scale Geographically Weighted Regression (MGWR) model, this study examines the spatial heterogeneity of carbon emissions and the mechanisms through which urban planning influences them. The results indicate that carbon emissions in Xi’an exhibit a “core–periphery” agglomeration pattern, with commercial land use exhibiting the highest emission intensity. Carbon emissions and land surface temperature are spatially coupled, consistent with a hypothesised positive feedback loop of the “dry heat island” effect. Morphological factors exhibit spatial non-stationarity: floor area ratio is positively associated with emissions in the old city centre, whereas mutual shading among super-high-rise buildings in the High-Tech Zone coincides with a weaker effect. Building density shows a positive association only where ventilation is limited. Land use mix and blue–green spaces show non-linear negative associations with emissions, with higher marginal benefits in arid–hot environments. This study proposes carbon reduction strategies for the renewal of old urban areas, business cores, and new ecological districts, providing empirical evidence and decision-making references for low-carbon spatial planning in cities within the climatic transition zone. Full article

With the continuous expansion of building scale and increasingly complex functions, pedestrian congestion within buildings has become increasingly prominent. To identify high-utilization spaces during the architectural design stage, so as to optimize the design at the source and effectively alleviate the risk of oversaturated spatial flow in super high-rise buildings, transportation hubs and other complex buildings, this paper investigates spatial flow estimation methods in the architectural design phase. First, based on detailed data from microscopic pedestrian simulation in buildings, this study conducts an in-depth analysis of the factors influencing spatial flow from the perspectives of spatial structure and pedestrian demand. Then, by incorporating the visual integration degree from space syntax and the proposed Origin-Destination (OD) influence range definition method that accounts for obstacle detours, a spatial utilization intensity index integrating both factors is developed. Furthermore, regression analysis is employed to achieve spatial flow estimation based on the constructed spatial utilization intensity index. Finally, taking the basement 1 floor of the Shenzhen Bay Super Headquarters Base C Tower connected with the metro as an example, the effectiveness of the proposed method is verified. The results show that the MAPE is 26%. This study provides an effective estimation method for the prediction of spatial flow in the architectural design stage. Full article

U-shaped steel−concrete composite beams (USCCBs) have been widely used in civil engineering due to their numerous advantages, including high load-bearing capacity, high rigidity, good ductility, short construction periods, and compatibility with the development of prefabricated buildings. In particular, USCCBs have been increasingly applied to super high-rise buildings and extra-large span bridges. Over the past decade or so, many new types of shear connectors and structural forms for USCCBs have been developed. Meanwhile, significant progress has been achieved in research on the flexural, shear, torsional, and fire-resistance performance of USCCBs, the seismic behavior of beam−column joints, and the strengthening of concrete beams with U-shaped steel casings. Nevertheless, challenges and limitations remain in both experimental research and practical applications. This paper presents a systematic review of recent research advances in USCCBs. Existing problems, development prospects, and future research priorities are comprehensively summarized and discussed, with the aim of further promoting the development and engineering application of USCCBs. Full article

Stairwells constitute critical escape routes for emergency evacuation during building disasters. The spread of fire smoke and the failure of lighting systems can significantly reduce visibility within stairwells, thereby adversely affecting evacuation speed. This issue is particularly pronounced in super high-rise buildings. In this study, a typical super high-rise building was selected as the experimental site. The variation laws of key parameters such as evacuation time, speed, and heart rate were investigated for groups with different gender proportions in stairwells under different visibility conditions. The experimental results show that: First, collaboration within multi-person groups can effectively mitigate the adverse impact of reduced visibility on evacuation speed. Second, different gender proportions within groups affect evacuation speed, with groups having a higher proportion of males demonstrating relatively faster evacuation speed. Third, under identical visibility conditions, the heart rates of multi-person groups during evacuation are generally lower than those of individual groups; in low-visibility environments, the heart rates of members within the same group are significantly higher than those under normal visibility conditions. Accordingly, this study proposes a mixed-gender group evacuation strategy under low-visibility conditions. The findings provide empirical data support for the formulation of emergency evacuation response strategies in super high-rise buildings. Full article

With the rapid development of mega-cities, clarifying the wind field characteristics of high-density urban areas is crucial for the accurate assessment of wind loads on newly built or temporary structures. Taking the high-density urban area of Shanghai as a case study, this research utilizes long-term wind field monitoring data obtained from a super high-rise building under construction. Statistical methods are employed to analyze the mean wind and fluctuating wind characteristics of such sites. The results indicate the following: the mean wind direction distribution is generally consistent with code statistics, with dominant wind directions varying significantly by season; the mean wind profile exponent at the site is 0.39, which is slightly higher than the reference value for Terrain Category D specified in codes; turbulence intensity tends to stabilize as wind speed increases, and the ratio of along-wind to cross-wind turbulence intensity is 1:0.59, which is slightly lower than the code-suggested value and shows a significant positive correlation with the gust factor. The mean peak factor is 2.52, while the mean longitudinal and lateral turbulence integral length scales are 118 m and 45 m, respectively. For strong wind samples, the longitudinal wind spectrum agrees well with the Davenport spectrum, whereas the lateral power spectrum correlates well with the Von Karman spectrum. This study provides a scientific basis and data support for wind load calculation and structural safety assessment in Shanghai and other high-density cities. Full article

As a dominant typology of urban development and a critical component of public infrastructure, super high-rise buildings have transitioned from a speed-driven expansion model to one that emphasizes a balanced approach between development pace and quality. Within the context of urban stock renewal, numerous super high-rise buildings now face pressing needs for retrofitting to enhance their sustainability and urban integration. This study establishes “urbanity”—defined as the capacity of the built environment to foster vibrant, inclusive, and sustainable urban life—as a core evaluation criterion for assessing the retrofitting and renewal of super high-rise buildings. Based on a comprehensive literature review and field investigations, 21 representative indicators were identified, and the key factors influencing the upgrading of such buildings were determined. Subsequently, 20 super high-rise buildings in Shanghai were selected as case studies, and their urbanity performance was assessed using a fuzzy comprehensive evaluation model (FCEM). The findings reveal common challenges, including architectural homogenization, functional singularity, limited vitality in near-ground spaces, weak integration with surrounding infrastructure, and inefficient utilization of urban landscape resources. Furthermore, the study analyzes urbanity-oriented enhancement strategies implemented in the selected cases and proposes targeted improvement measures across five key dimensions: building morphology, functional configuration, near-ground space, infrastructure, and urban landscape. The research contributes to the body of knowledge on sustainable urban regeneration by providing a practical evaluation framework and actionable strategies for retrofitting super high-rise buildings. The findings aim to support more livable, inclusive, and resilient urban environments, with implications for both Chinese and global cities facing similar challenges in high-density urban contexts. Full article

To enhance construction efficiency and structural stability, this study investigates the mechanical behavior and deformation characteristics of a jacking steel platform system used in the core-tube construction of a supertall building. Field monitoring was conducted on site to record stress, settlement, and inclination during the jacking, construction, and self-climbing stages. A finite element model was developed to simulate the platform’s mechanical response and validated against the field measurements. Results indicate that stress and deformation remained within safe limits throughout all stages, and the vertical deformation difference between the core tube and the outer frame was primarily governed by concrete shrinkage and creep. An improved modular design was proposed to address connection limitations in the steel truss, and cross-section optimization was applied using the stress ratio method. Comparative analysis against the original diamond-type truss baseline showed that the improved system increased overall strength by 5.88% and stiffness by 4.82% while enhancing truss versatility and structural stability. These findings provide a technical basis for the modular design and optimization of jacking steel platform systems, contributing to safer and more efficient construction practices. Full article

This paper proposes a hybrid integer optimization method based on the Whale Optimization Algorithm (WOA) for the asymmetric central air conditioning chiller system of a 530-m super high-rise building in Guangzhou. Firstly, a three-hidden-layer multilayer perceptron (MLP) chiller model based on 16,276 sets of measured data and a gradient boosting regression cooling tower model based on 21,369 sets of operating condition data were constructed, achieving high-precision modeling of the energy consumption of all equipment in the chiller system. Secondly, a hybrid encoding strategy of “threshold truncation + continuous relaxation” was proposed to integrate discrete on-off states and continuous operating parameters into WOA, and a three-layer constraint repair mechanism was designed to ensure the physical feasibility of the optimization process and the safe operation of equipment. Verification across three load scenarios—low, medium, and high—showed that the optimized system’s energy efficiency ratio (EER) increased by 15.01%, 12.61%, and 11.86%, respectively, with energy savings of 12.91%, 11.18%, and 10.58%. The annual rolling optimization results showed that the average EER increased from 5.07 to 5.88 (16.1%), with energy savings ranging from 8.59% to 18.92%. Sensitivity analysis indicated that pump quantity is the most influential parameter affecting system energy consumption, with an additional pump reducing it by 1.1%. The optimization method proposed in this paper meets the minute-level real-time scheduling requirements of building automation systems and provides an implementable solution for energy-saving optimization of central air conditioning chiller systems in super high-rise buildings. Full article

As one of the most technically and managerially complex types of construction projects, super-high-rise buildings require deep multidisciplinary integration and intensive collaboration throughout their lifecycle. Conventional stage-based delivery models, such as the EPC, are often inadequate for handling this complexity. In recent years, the integrated Financing–Engineering, Procurement and Construction–Operation (F+EPC+O) model has emerged to address lifecycle governance challenges in building projects. This study explores how an investment-led F+EPC+O model builds dynamic capabilities to enable lifecycle collaboration in complex projects. It is based on a case study of the Xiamen Hemei Center and employs a qualitative case study approach to examine the operation of an internal F+EPC+O in the project. Drawing on multi-source data, including internal archives, BIM/CIM logs, and interviews, the findings identify three elements—lifecycle incentive alignment, internal power symmetry, and extended operation duration—that shape the Sensing–Seizing–Reconfiguring (SSR) capabilities of the approach. Specifically, Sensing is achieved through NPV-based decision frameworks and cross-stage trade-off lists; Seizing is achieved through BIM/CIM issue closure and joint rapid-cycle decision-making; and Reconfiguring is achieved through performance feedback and institutionalized knowledge repositories. The findings indicate that the SSR dynamic cycle transforms institutional integration into value co-creation, turning project complexity into a source of collaborative advantage. Full article

Understanding spatial characteristics of urban building systems is critical for unraveling urban building stock growth patterns, addressing housing vacancy challenges, and advancing urban carbon neutrality. However, existing research on built environment stocks and housing vacancy spatial distribution remains limited, particularly in underdeveloped cross-river cities—where rapid urbanization often prioritizes scale expansion over demand matching, leading to unresolved issues of resource waste and environmental pressure. This study integrated material stocks analysis (MSA) and geographical information system (GIS) to uncover the spatial patterns of urban building material stocks and housing vacancy at a high spatial resolution for Nanchang, China—a typical underdeveloped cross-river city facing the “scale expansion trap” in its urbanization across the Ganjiang River. Results show that (1) Nanchang’s building stock exhibits a “butterfly-shaped” spatial pattern centered on the Ganjiang River, with simultaneous horizontal expansion (40-fold urban area growth since 1949) and vertical growth (super high-rises in new west-bank districts), reflecting aggressive cross-river scale expansion; (2) the total building material stock reached 1034 Mt (204 t/cap) in 2021, with over 85% accumulated post-2000—coinciding with large-scale cross-river development. Vacant buildings locked in 405 Mt of materials (39.17%), which is a direct consequence of the “scale expansion trap” where construction outpaced actual demand; (3) total embodied carbon emissions from building materials amounted to 264 Mt, with 104 Mt (39.39%) attributed to vacant stocks. This “vacant carbon lock-in” stems from mismatched urban construction and actual demand in the process of cross-river scale expansion; (4) spatially, high-value clusters of material stocks and carbon emissions overlapped at two cores (old town and Honggutan CBD), while housing vacancy rates were significantly higher in the urban periphery and Ganjiang’s west bank—the primary areas of cross-river scale expansion—than in the old town and east bank. These findings empirically demonstrate how the “scale expansion trap” in cross-river urbanization drives building stock vacancy and carbon lock-in. These findings also offer data-driven strategies for optimizing urban resource allocation, reducing housing vacancy, and promoting low-carbon transitions, especially for other underdeveloped cross-river cities globally. Full article

Basalt fiber (BF) can notably improve the mechanical properties of lightweight aggregate concrete (LWAC) through its crack-bridging and pull-out mechanisms, making it suitable for application in super high-rise buildings and large-span structures. This study assesses the influence of BF contents of 0%, 0.1%, 0.3%, 0.5%, and 0.7% (relative to the weight of cementitious materials) on the workability, mechanical properties, and microstructure of LWAC. The results showed that adding BF to LWAC can moderately weaken the slump, significantly enhance the mechanical properties, and lead to a maximum increase in specific strength of 7.3%. Compared with LWAC without BF, the maximum increases in compressive strength, flexural strength, and elastic modulus of LWAC with BF at 28 days were 24.7%, 33.9%, and 38.57%, respectively. In the microstructure, BF can connect the cracks in the internal structure of concrete, which is an important factor to consider when choosing a fiber to improve the mechanical properties of concrete. These conclusions provide a reference point for improving the mechanical properties of LWAC. Full article

Super high-rise buildings of 400 m and above are currently rare globally, making their design and construction data invaluable. Due to their enormous size, the structural safety, architectural effect, and construction cost are key concerns of all parties. This study employs parametric analysis to research the lateral force-resisting system and key local structural issues of a 400 m under-construction super-high-rise structure. The overall analysis results show that the 8-mega-column scheme can relatively well balance architectural effect and structural performance; the 5-belt truss design minimizes the steel consumption. The local research results indicate that the inward inclination of bottom columns leads to increased axial forces in floor beams significantly, necessitating reinforcement; horizontal braces directly connected to the core tube enhance folded belt truss integrity under rare earthquakes; failure of bottom gravity columns in the folded secondary frame increases beam bending moments and axial forces substantially. Steel consumption sensitivity analysis shows that when the structural first-order period is reduced by 0.1 s, adjusting the section sizes of the members in the belt truss minimizes the increase in steel consumption, while adjusting steel beams maximizes it. These findings provide essential design insights for similar super-high-rise projects. Full article

Climate change amplifies heat wave effects on outdoor thermal comfort by increasing their frequency, duration, and intensity. The urban heat island effect worsens heat risks in cities and impacts resilience. Nature-based solution (NBS) with tree plantation was reported as an effective mitigation measure. This simulation study, by the well-validated ENVI-met model, aimed to investigate the impact of different tree planting strategies and building parameters on urban heat risk mitigation and microclimate during a typical hot summer day. Hypothetical skyscrapers and super high-rise buildings were assumed in the study site located in southern China. Adopting meteorological inputs from a typical year, the simulation results revealed that both mean radiant temperature (T_mrt) and physiological equivalent temperature (PET) were elevated (T_mrt > 60 °C and PET > 50 °C) in early afternoon in sunlit areas. Three mitigation approaches with different tree planting locations were investigated. While all approaches demonstrated effective cooling (PET down to <35 °C) in the proximity of trees, a superior approach for mitigating the heat risks was not evident. Within the building array, the shade of bulky structures also lowered T_mrt and PET to a thermally comfortable level in the late afternoon. Combining open-space tree planting with optimized building designs is recommended to mitigate heat risks and enhance urban resilience while promoting outdoor activities and their health benefits. Full article