Buildings

29 pages, 5330 KiB

Open AccessArticle

Research on Tourist Satisfaction Evaluation of Macau’s Built Heritage Space Under the Genius Loci

by Pohsun Wang, Chenxi Li and Jing Liu

Buildings 2025, 15(10), 1701; https://doi.org/10.3390/buildings15101701 (registering DOI) - 17 May 2025

As a typical World Cultural Heritage city, Macau has a special regional identity and outstanding cultural value in the built heritage and spatial identity of the city. As contemporary cultural industries have undergone rapid development to transform architectural heritage spaces into displays into [...] Read more.

As a typical World Cultural Heritage city, Macau has a special regional identity and outstanding cultural value in the built heritage and spatial identity of the city. As contemporary cultural industries have undergone rapid development to transform architectural heritage spaces into displays into showcases of heritage significance, an adaptive transformation strategy is not to be ignored. Although the current transformations demonstrate functional efficacy, they lack of a cultural environment, the Gestalt of the Genius Loci, and a limited visitor experience. For this research, we use the Genius Loci theory to identify constitutive spatial elements and derive theory-based evaluation criteria for the Mandarin’s House, which acts as the case study. It provides a comprehensive evaluation framework across four dimensions: spatial perception, cultural identity, emotional engagement, and functional attributes, each one comprising 20 specific indicators. This research reviews the factors that affect the recognition of cultural identity through quantitative analysis using Importance–Performance Analysis (IPA), evaluating the importance–performance relationships of these indicators. Critical gaps between visitor expectations and current spatial performance are found. Therefore, four optimization strategies are proposed accordingly. (1) Physical experience is enriched through reconstruction of spatial narrative; (2) spiritual experience is reinforced through cultural memory activation; (3) regional characteristics are strengthened through the contextualization of heritage values; and (4) sustainable development mechanisms for adaptive reuse are established. Taken as a systematic approach, it offers both theoretical and practical insight into the regeneration of the architectural heritage spaces in the World Cultural Heritage cities. Full article

(This article belongs to the Special Issue Built Heritage Conservation in the Twenty-First Century: 2nd Edition)

18 pages, 8299 KiB

Open AccessArticle

The Influence of Stone Cladding Elements on the Seismic Behaviour of a Bell Tower

by Luciana Di Gennaro, Mariateresa Guadagnuolo, Mariano Nuzzo and Giuseppe Faella

Buildings 2025, 15(10), 1700; https://doi.org/10.3390/buildings15101700 (registering DOI) - 17 May 2025

Abstract

Bell towers, due to their slender geometry and structural configuration, are among the buildings most susceptible to deterioration from weathering and seismic events. These aspects influence the structural assessment of these historic towers, which is essential for their conservation and maintenance. The “Carmine [...] Read more.

Bell towers, due to their slender geometry and structural configuration, are among the buildings most susceptible to deterioration from weathering and seismic events. These aspects influence the structural assessment of these historic towers, which is essential for their conservation and maintenance. The “Carmine Maggiore” bell tower in Naples (Italy) has been an important and prominent landmark of the city for centuries. It is square in plan and 72 m high. Over time, it suffered extensive damage and was severely damaged by the earthquake of 1456. Reconstruction began in the first decade of the 17th century and the original design was modified, adding two stories and changing the shape of the plan to octagonal. In the centuries that followed, the structure was damaged again and further interventions were carried out, adding tie-rods and replacing damaged elements. Today, the bell tower has very elaborate façades with mouldings and decorations, so that the supporting structure appears to be covered with plaster, stucco, and stone elements. This paper describes the results of FEM analyses of the bell tower, obtained from models with different levels of complexity to evaluate the influence of stone cladding elements on the seismic behaviour. In particular, the difference in the IS safety indices, calculated as the ratio of capacity to demand, exceeds 15%, due to the mechanical consistency of the cladding elements, which contribute significantly to both stiffness and strength. Full article

(This article belongs to the Special Issue Mechanics of Masonry Towers)

25 pages, 11111 KiB

Open AccessArticle

Integrating Backscattered Electron Imaging and Multi-Feature-Weighted Clustering for Quantification of Hydrated C₃S Microstructure

by Xin Wang and Yongjun Luo

Buildings 2025, 15(10), 1699; https://doi.org/10.3390/buildings15101699 (registering DOI) - 17 May 2025

Abstract

The microstructure of cement paste is governed by the hydration of its major component, tricalcium silicate (C₃S). Quantitative analysis of C₃S microstructural images is critical for elucidating the microstructure-property correlation in cementitious systems. Existing image segmentation methods rely on [...] Read more.

The microstructure of cement paste is governed by the hydration of its major component, tricalcium silicate (C₃S). Quantitative analysis of C₃S microstructural images is critical for elucidating the microstructure-property correlation in cementitious systems. Existing image segmentation methods rely on image contrast, leading to a struggle with multi-phase segmentation in regions with close grayscale intensities. Therefore, this study proposes a weighted K-means clustering method that integrates intensity gradients, texture variations, and spatial coordinates for the quantitative analysis of hydrated C₃S microstructure. The results indicate the following: (1) The deep convolutional neural network with guided filtering demonstrates superior performance (mean squared error: 53.52; peak signal-to-noise ratio: 26.35 dB; structural similarity index: 0.8187), enabling high-fidelity preservation of cementitious phases. In contrast, wavelet denoising is effective for pore network analysis but results in partial loss of solid phase information. (2) Unhydrated C₃S reflects optimal boundary clarity at intermediate image relative resolutions (0.25–0.56), while calcium hydroxide peaks at 0.19. (3) Silhouette coefficients (0.70–0.84) validate the robustness of weighted K-means clustering, and the Clark–Evans index (0.426) indicates CH aggregation around hydration centers, contrasting with the random CH distribution observed in Portland cement systems. Full article

(This article belongs to the Section Building Materials, and Repair & Renovation)

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11 pages, 3622 KiB

Open AccessArticle

Impact of Wood on Perception of Transient and Steady-State Indoor Thermal Environments

by Denise (Blankenberger) Gravelle, Jason Stenson, Mark Fretz and Kevin Van Den Wymelenberg

Buildings 2025, 15(10), 1698; https://doi.org/10.3390/buildings15101698 (registering DOI) - 17 May 2025

Abstract

Wood is often used as an interior surface finish in buildings, including exposed cross-laminated timber panels and other structural mass timber members. Building occupants generally have a positive reaction to visible wood elements used in building interiors due to the visual qualities associated [...] Read more.

Wood is often used as an interior surface finish in buildings, including exposed cross-laminated timber panels and other structural mass timber members. Building occupants generally have a positive reaction to visible wood elements used in building interiors due to the visual qualities associated with wood being a natural material. This study aims to identify any thermal comfort impacts of wood interior environments using subjective occupant-reported perceived thermal sensation during two experiments conducted in a climate chamber fitted with either white-painted gypsum wallboard or unfinished laminated Douglas Fir wall panels. In the first experiment, the thermal environment was continually varied while the visual stimulus of the wall type remained constant. Irrespective of wood or white wall treatment type, thermal history played a significant role in the perceived thermal comfort of participants under continually modulating temperatures. In the second experiment, a slightly warm steady-state thermal environment was maintained while one of the two wall treatments was revealed from behind a black curtain. While the shift in thermal sensation toward neutral was greater with wood walls than with white walls, the difference was not found to be statistically significant and appears to diminish after 15 min of exposure to the new visual surroundings. Full article

(This article belongs to the Section Building Energy, Physics, Environment, and Systems)

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15 pages, 2272 KiB

Open AccessArticle

Development and Validation of High-Performance Soil-Cement Panels: A Sustainable and Economical Alternative for Civil Construction

by Bernat Vinolas Prat, Demisson Renato Ferreira, Luis Guilherme Monteiro Oliveira, João Vinícios Wirbitzki da Silveira, Frank Alisson De Carvalho, Marcus Vinícius Felix, Ellem Eva Augusto Rocha, José Domingos Fabris and Alexandre Christófaro Silva

Buildings 2025, 15(10), 1697; https://doi.org/10.3390/buildings15101697 (registering DOI) - 17 May 2025

Abstract

Despite its advantages, conventional soil-cement has limitations in terms of mechanical strength and durability, especially in environments with high humidity or high structural demands. The development of high-performance soil-cement (HPSC) presents significantly superior mechanical properties. The decentralized production of these panels has resulted [...] Read more.

Despite its advantages, conventional soil-cement has limitations in terms of mechanical strength and durability, especially in environments with high humidity or high structural demands. The development of high-performance soil-cement (HPSC) presents significantly superior mechanical properties. The decentralized production of these panels has resulted in a cost reduction of more than 40%, making them an affordable alternative for low-income communities. Even so, providing technical support for the popularization of HPSC is crucial for the advancement of civil construction and to enable the expansion of affordable and sustainable housing for vulnerable communities. This study focuses on the development of a high-performance soil-cement panel, including its manufacturing process and the materials used. The panel was produced using Yellow Argisol soil, found locally in abundant quantities, modified with sand. Measurements of flexural strength and water absorption were carried out, together with a comparison of the strength of high-performance concrete (HPC) found in the literature. The developed panels present an average flexural strength of 6.71 MPa. Additionally, water absorption reached 5.99%, indicating the high performance of this material, which is comparable to high-performance concrete but more economical and sustainable. This contribution confirms the viability of transferring HPSC technology and highlights its social impact on civil construction. Full article

(This article belongs to the Special Issue Advanced Construction Materials and Technologies for a Sustainable Future)

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33 pages, 10831 KiB

Open AccessArticle

Impact of Multi-Defect Coupling Effects on the Safety of Shield Tunnels and Cross Passages

by Xiaokai Niu, Hongchuan Xing, Wei Li, Wei Song and Zhitian Xie

Buildings 2025, 15(10), 1696; https://doi.org/10.3390/buildings15101696 (registering DOI) - 17 May 2025

Abstract

As urban rail transit networks age, understanding the synergistic impacts of multi-defect interactions on tunnel structural safety has become critical for underground infrastructure maintenance. This study investigates defect interaction mechanisms in shield tunnels and cross passages of Beijing Metro Line 8, integrating field [...] Read more.

As urban rail transit networks age, understanding the synergistic impacts of multi-defect interactions on tunnel structural safety has become critical for underground infrastructure maintenance. This study investigates defect interaction mechanisms in shield tunnels and cross passages of Beijing Metro Line 8, integrating field monitoring, numerical simulations, and Bayesian network analysis. Long-term field surveys identified spatiotemporal coupling characteristics of four key defects—lining leakage, structural voids, material deterioration, and deformation—while revealing typical defect propagation patterns such as localized leakage at track beds and drainage pipe-induced voids. A 3D fluid–solid coupling numerical model simulated multi-defect interactions, demonstrating that defect clusters in structurally vulnerable zones (e.g., pump rooms) significantly altered pore pressure distribution and intensified displacement, whereas void expansion exacerbated lining uplift and asymmetric ground settlement. Stress concentrations were notably amplified at tunnel–cross passage interfaces. The Bayesian network risk model further validated the dominant roles of defect volume and burial depth in controlling structural safety. Results highlight an inverse correlation between defect severity and structural integrity. Based on these findings, a coordinated maintenance framework combining priority monitoring of high-stress interfaces with targeted grouting treatments is proposed, offering a systematic approach to multi-defect risk management that bridges theoretical models with practical engineering solutions. Full article

(This article belongs to the Special Issue Resilience of Urban Underground Space: Planning, Design, Assessment and Enhancement)

16 pages, 6537 KiB

Open AccessArticle

The Impact of Stray Currents on Chloride Transport in the Concrete of Urban Rail Transit Structures

by Yuancheng Ni, Eryu Zhu and Liangjiang Chen

Buildings 2025, 15(10), 1695; https://doi.org/10.3390/buildings15101695 (registering DOI) - 17 May 2025

Abstract

To study the chloride transport properties of urban rail transit structures under the action of stray currents, electrochemical tests were employed as part of this paper to investigate the impact of stray currents on cementitious materials and pore structure and further analyze the [...] Read more.

To study the chloride transport properties of urban rail transit structures under the action of stray currents, electrochemical tests were employed as part of this paper to investigate the impact of stray currents on cementitious materials and pore structure and further analyze the chloride distribution of specimens in different conditions. Results show that a stray current accelerates calcium ion precipitation in chloride solutions, reducing calcium hydroxide content compared to unelectrified specimens. This dissolution alters the concrete pore structure, increasing porosity by 26.3%, 31.2%, and 36.1% for specimens electrified at 50 mA, 100 mA, and 150 mA, respectively, after 28 days. The effect coefficient k_p of stray currents on the porosity of concrete is given with the test results. Electrified specimens have a higher chloride content compared to unelectrified specimens, with free chloride increasing more than bound chloride as current and time increase. The chloride ion binding capacity of concrete electrified at 150 mA is only 60% that of unelectrified, indicating the significant weakening effect of stray currents on it. Full article

(This article belongs to the Section Building Materials, and Repair & Renovation)

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20 pages, 6167 KiB

Open AccessArticle

DyEHS: An Integrated Dynamo–EPANET–Harmony Search Framework for the Optimal Design of Water Distribution Networks

by Francesco De Paola, Giuseppe Speranza, Giuseppe Ascione and Nunzio Marrone

Buildings 2025, 15(10), 1694; https://doi.org/10.3390/buildings15101694 (registering DOI) - 17 May 2025

Abstract

The integration of Building Information Modeling (BIM) with intelligent optimization techniques can significantly enhance the design efficiency of water distribution networks (WDNs). Despite this, the dynamic interoperability between BIM platforms and hydraulic simulation tools remains limited. This study introduces DyEHS (Dynamo–EPANET–Harmony Search), a [...] Read more.

The integration of Building Information Modeling (BIM) with intelligent optimization techniques can significantly enhance the design efficiency of water distribution networks (WDNs). Despite this, the dynamic interoperability between BIM platforms and hydraulic simulation tools remains limited. This study introduces DyEHS (Dynamo–EPANET–Harmony Search), a novel workflow integrating Autodesk Civil 3D, EPANET, and Harmony Search via Dynamo, to address this gap. DyEHS enables the automated optimization of pipe diameters and network layouts, aiming to minimize capital costs while satisfying hydraulic constraints. In a real-world case study, DyEHS achieved a 15% reduction in the total pipe network costs compared to traditional uniform-diameter designs, while ensuring that all nodes maintained a minimum pressure of 25 m. This quantifiable improvement highlights the tool’s potential for practical engineering applications, offering a robust, adaptable, and fully integrated BIM-based solution for WDN design. Full article

(This article belongs to the Section Construction Management, and Computers & Digitization)

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25 pages, 4268 KiB

Open AccessArticle

Numerical Study on Hydraulic Coupling and Surrounding Rock Deformation for Tunnel Excavation Beneath Reservoirs

by Shaodan Wang, Guozhu Zhang, Zihao Yu and Zhou Ya

Buildings 2025, 15(10), 1693; https://doi.org/10.3390/buildings15101693 (registering DOI) - 17 May 2025

Abstract

Tunnels beneath reservoirs are prone to significant geohazards, such as water and mud surges during excavation. To mitigate construction risks during the excavation of the Dajianshan Tunnel, a three-dimensional refined numerical model was developed. This study employed a fluid–solid coupling numerical model to [...] Read more.

Tunnels beneath reservoirs are prone to significant geohazards, such as water and mud surges during excavation. To mitigate construction risks during the excavation of the Dajianshan Tunnel, a three-dimensional refined numerical model was developed. This study employed a fluid–solid coupling numerical model to analyze the temporal and spatial variations of the filtration field during the excavation and drainage of the tunnel section beneath the reservoir, and to assess its impact on pore pressure at the reservoir bottom. The results indicate that excavation and drainage initially cause a rapid decrease in pore water pressure at the tunnel vault, which gradually stabilizes. Furthermore, the extent of disturbance in the surrounding rock’s filtration field increases with distance from the tunnel vault. When the excavation intersects fault zones, water surges significantly affect filtration conditions at the reservoir bottom, resulting in a pore pressure reduction of approximately 5.2 kPa. Additionally, under blasting disturbance conditions, a larger disturbance range and higher permeability in the loosened zone led to greater pore pressure fluctuations, posing increased challenges for excavation safety and drainage management. This study provides a predictive model and methodology to prevent construction accidents during tunnel excavation, offering valuable insights for ensuring safety during the construction process. Full article

(This article belongs to the Section Building Structures)

14 pages, 3273 KiB

Open AccessArticle

Improved Autogenous Healing of Concrete with Superabsorbent Polymers Evaluated Through Coupled and Air-Coupled Ultrasound

by Gerlinde Lefever

Buildings 2025, 15(10), 1691; https://doi.org/10.3390/buildings15101691 (registering DOI) - 17 May 2025

Abstract

Superabsorbent polymers have been introduced into cementitious materials to solve issues related to early-age cracking, caused by shrinkage, and manual repair. A general improvement of autogenous healing is noticed, while the extent and effectiveness depend on the type of hydrogel and the amount [...] Read more.

Superabsorbent polymers have been introduced into cementitious materials to solve issues related to early-age cracking, caused by shrinkage, and manual repair. A general improvement of autogenous healing is noticed, while the extent and effectiveness depend on the type of hydrogel and the amount included. To evaluate the self-healing effectiveness, the regain of mechanical performance needs to be assessed. However, such evaluation requires destructive testing, meaning that the healing progress cannot be followed over time. As a solution, air-coupled ultrasonic testing was used within this study, adopting a novel laser interferometer as a receiver, to estimate the regained properties of cementitious mixtures with and without superabsorbent polymers. The sensitivity of ultrasonic waves to the elastic properties of the material under study allows us to monitor the crack healing progress, while the semi-contactless nature of the procedure enables an easy and reliable measurement. Up to 80% recovery in ultrasonic velocity was achieved with reference concrete, while SAP concrete demonstrated up to 100% recovery after wet–dry curing. Following microscopic analysis, up to 19% visual crack closure was obtained for reference concrete, compared to a maximum of 50% for SAP mixtures, for average crack widths between 250 µm and 450 µm. Full article

(This article belongs to the Special Issue Application and Characterization of Innovative Cementitious Materials in the Construction Industry)

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21 pages, 1280 KiB

Open AccessArticle

Experimental and Numerical Study on Reinforced Concrete Columns Strengthened with Lightweight Alkali-Activated Slag Concrete and X-Type Encased Steel

by Jing Zhu, Zijie Wen, Yuankai Li, Xiaomeng Hou and Yiqi Lu

Buildings 2025, 15(10), 1692; https://doi.org/10.3390/buildings15101692 (registering DOI) - 16 May 2025

Abstract

As a key load-bearing component in building structures, the effective strengthening of reinforced concrete (RC) columns is critical to enhancing their structural reliability and service life. To tackle the issue of excessive self-weight from the increasing section strengthening method and further optimize the [...] Read more.

As a key load-bearing component in building structures, the effective strengthening of reinforced concrete (RC) columns is critical to enhancing their structural reliability and service life. To tackle the issue of excessive self-weight from the increasing section strengthening method and further optimize the seismic performance of encased steel strengthening, this paper presents a novel composite strengthening method for RC columns, which is characterized by using Lightweight Alkali-Activated Slag Concrete (LAASC) as the strengthening layer and an X-type encased steel structure. By conducting axial compression tests on six columns and utilizing in-depth research on small eccentric compression and hysteresis performance through numerical simulation, the specific effects of different strengthening materials and encased steel forms on the mechanical properties of the columns are systematically explored. Experimental results indicate that compared to ordinary concrete strengthening layers, LAASC can reduce the self-weight of the strengthening layer by 25%, boost the bearing capacity of the strengthened components by 37%, and enhance the vertical deformation capacity by 100%. Numerical simulation also confirms that X-type encased steel composite strengthening can effectively control bending deformation under small eccentric compression, reducing lateral deflection by 30–35% compared to un-strengthened columns. Under horizontal reciprocating loading, the cumulative energy dissipation of X-type encased steel composite-strengthened columns is 15–30% higher than that of traditional steel encased composite-strengthened columns, reflecting the diagonal bracing effect of the X-type batten plates. Full article

(This article belongs to the Section Building Structures)

27 pages, 3701 KiB

Open AccessArticle

Dynamic Simulation of Solar-Assisted Medium-Depth Ground Heat Exchanger Direct Heating System

by Le Chang, Lingjun Kong, Yangyang Jing, Wenshuo Zhang, Sifang Fu, Xueming Lu, Haiqing Yao, Xiaona Xie and Ping Cui

Buildings 2025, 15(10), 1690; https://doi.org/10.3390/buildings15101690 (registering DOI) - 16 May 2025

Abstract

The global challenges of rising energy consumption and carbon emissions underscore the urgent need for efficient and sustainable heating solutions in the building sector. The implementation of high-performance buildings that envelope insulation and the increasing adoption of low-temperature radiant heating systems have significantly [...] Read more.

The global challenges of rising energy consumption and carbon emissions underscore the urgent need for efficient and sustainable heating solutions in the building sector. The implementation of high-performance buildings that envelope insulation and the increasing adoption of low-temperature radiant heating systems have significantly reduced the water temperature required from heat sources, enabling greater compatibility with renewable energy systems. In this study, we propose a renewable energy heating system incorporating a solar-assisted medium-depth ground heat exchanger (MDGHE). A dynamic simulation model of the solar-assisted MDGHE system was developed in TRNSYS, featuring a novel MDGHE module specifically developed to improve simulation accuracy. A case study of a residential building in China was conducted to evaluate the performance of the proposed system. The simulation results demonstrate that while the standalone MDGHE covers 71.9% of the building’s heating demand, integrating solar collectors with the MDGHE can increase this coverage to 99.9%, enabling full compliance with heating requirements without relying on conventional heat pumps. The results revealed that the system’s COP reached 9.26. Compared with the traditional medium-depth ground source heat pump system with the COP of 4.84, the energy efficiency of this system has been enhanced by 47.7%. A static payback period of 7 years has been obtained compared with the cost of central heating service for residential buildings. These findings highlight the potential of solar-geothermal hybrid systems as a sustainable alternative to traditional heating methods. Full article

(This article belongs to the Special Issue Sustainable Design and Smart Control of Building Energy to Accelerate Net-Zero Operations)

22 pages, 8356 KiB

Open AccessArticle

A Flood Prevention Design for Guangzhou Metro Stations Under Extreme Rainfall Based on the SCS-CN Model

by Xin Chen, Hongyu Kuai, Xiaoqian Liu and Bo Xia

Buildings 2025, 15(10), 1689; https://doi.org/10.3390/buildings15101689 - 16 May 2025

Abstract

With the intensification of global climate change, the underground rail transit system of Guangzhou, as a major coastal city, faces severe flood risks. Through field investigations of 313 metro stations, this study identified 472 flood-related risk points, primarily involving water backflow at low-lying [...] Read more.

With the intensification of global climate change, the underground rail transit system of Guangzhou, as a major coastal city, faces severe flood risks. Through field investigations of 313 metro stations, this study identified 472 flood-related risk points, primarily involving water backflow at low-lying stations, insufficient elevation of structural components, and the threat of overbank flooding from adjacent rivers. By integrating GIS-based spatial analysis with the SCS-CN runoff model, an extreme rainfall scenario (534.98 mm) was simulated, revealing a maximum runoff depth of 484.23 mm. Based on these results, it is recommended to raise the flood protection design elevation to 582 mm and install additional waterproof barriers. Optimization strategies include establishing flood protection standards for new stations based on site topography and runoff volume, elevating station platforms or adding waterproof structures at existing stations, and upgrading drainage systems with real-time monitoring and early-warning mechanisms. This study emphasizes the necessity for Guangzhou’s metro system to integrate climate-adaptive urban planning and technological innovation to enhance flood resilience and promote sustainable urban development. Full article

(This article belongs to the Special Issue Resilient Urban and Architecture Design: Strategies for Low-Carbon and Climate-Adaptive Cities)

21 pages, 5473 KiB

Open AccessArticle

A Study on the Mechanical Properties and Impact Resistance of Hybrid Fiber-Reinforced Cement-Based Composites with Low Water–Cement Ratios

by Shuangxi Li, Xinhui Wei and Ziming Dang

Buildings 2025, 15(10), 1688; https://doi.org/10.3390/buildings15101688 - 16 May 2025

Abstract

This study investigates the mechanical and impact resistance properties of high-performance cementitious composites (HPCCs) incorporating hybrid fibers under a low water-to-binder ratio, with a focus on the multi-scale synergistic effects of different fiber types. Aramid fibers (AFs), basalt fibers (BFs), and calcium sulfate [...] Read more.

This study investigates the mechanical and impact resistance properties of high-performance cementitious composites (HPCCs) incorporating hybrid fibers under a low water-to-binder ratio, with a focus on the multi-scale synergistic effects of different fiber types. Aramid fibers (AFs), basalt fibers (BFs), and calcium sulfate whiskers (CSWs) contribute to reinforcement at the macro, meso, and micro levels, respectively. Experimental results reveal that hybrid fiber systems significantly outperform single-fiber composites in terms of both impact resistance and crack suppression. The optimal mix design—comprising 3% CSW, 0.067% AF, and 0.033% BF—achieved a remarkable 233.3% increase in impact energy absorption compared to the control group. This enhancement is attributed to the complementary roles of the three fibers: CSWs refine the pore structure and mitigate microcrack propagation; AFs effectively restrain the development of macrocracks due to their high tensile strength and aspect ratio; and BFs contribute to energy dissipation through crack bridging and mechanical interlocking. Statistical analysis using the two-parameter Weibull distribution accurately characterized the variability and reliability of the impact resistance data, while pore structure analysis confirmed a reduction in average pore diameter and a more favorable pore size distribution. These findings underscore the effectiveness of fiber hybridization in improving the mechanical behavior and dynamic load resistance of cement-based composites, offering valuable insights for their application in demanding engineering scenarios. Full article

(This article belongs to the Section Building Materials, and Repair & Renovation)

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32 pages, 14609 KiB

Open AccessArticle

How Does the Platform Economy Affect Urban System: Evidence from Business-to-Business (B2B) E-Commerce Enterprises in China

by Pengfei Fang, Xiaojin Cao, Yuhao Huang and Yile Chen

Buildings 2025, 15(10), 1687; https://doi.org/10.3390/buildings15101687 - 16 May 2025

Abstract

In the new paradigm where the digital economy is profoundly reshaping urban spatial organization, how the platform economy transcends traditional geographical constraints to restructure the urban system has become a strategic issue in urban geography and regional economics. This study develops an innovative [...] Read more.

In the new paradigm where the digital economy is profoundly reshaping urban spatial organization, how the platform economy transcends traditional geographical constraints to restructure the urban system has become a strategic issue in urban geography and regional economics. This study develops an innovative measurement framework based on Business-to-Business (B2B) e-commerce enterprises to analyze platform-driven urban systems across 337 Chinese cities. Using spatial autocorrelation, rank-size distributions, and urban scaling laws, we reveal spatial differentiation patterns of cities’ B2B platforms. Combining Ordinary Least Squares (OLS) and random forest models with Partial Dependence Plots (PDP), Individual Conditional Expectations (ICE), and Locally Weighted Scatterplot Smoothing (LOWESS), we uncover non-linear mechanisms between platform development and urban attributes. Results indicate that (1) B2B platforms exhibit “superliner agglomeration” and “gradient locking”, reinforcing advantages in top-tier cities; (2) platform effects are non-linear, with Gross Domestic Product (GDP), Information Technology (IT) employment, and service sector shares showing threshold-enhanced marginal effects, while manufacturing bases display saturation effects; and (3) regional divergence exists, with eastern consumer-oriented platforms forming digital synergies, while western manufacturing platforms face path dependence. The findings highlight that platform economy evolution is shaped by a “threshold–adaptation–differentiation” mechanism rather than neutral diffusion. This study provides new insights into urban system restructuring under digital transformation. Full article

(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)

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23 pages, 5363 KiB

Open AccessArticle

Which Distance-Decay Function Can Improve the Goodness of Fit of the Metro Station Ridership Regression Model? A Case Study of Beijing

by Zhenbao Wang, Shihao Li and Yushuo Zhang

Buildings 2025, 15(10), 1686; https://doi.org/10.3390/buildings15101686 - 16 May 2025

Abstract

Incorporating the distance-decay effects of facility points into the analysis of metro ridership helps generate more precise and actionable strategies for station area renewal. The majority of existing studies, however, calculated the built environment variables based on the same pedestrian catchment areas (PCAs) [...] Read more.

Incorporating the distance-decay effects of facility points into the analysis of metro ridership helps generate more precise and actionable strategies for station area renewal. The majority of existing studies, however, calculated the built environment variables based on the same pedestrian catchment areas (PCAs) of metro stations and failed to consider the impact of distance decay from POIs (points of interest) on the accuracy of metro station ridership regression models. The objective of this study is to determine which distance-decay function best improves the fit of the metro ridership regression model and investigate the effect of the built environment on ridership under the optimal distance-decay model. Based on the distribution density of metro stations in Beijing, the research area is divided into three zones with different PCAs. Built environment variables for all metro stations are aggregated according to the PCA scope. Various distance-decay functions are examined to determine how the accuracy of the Multi-scale Geographically Weighted Regression (MGWR) model is affected by built environment variables calculated from POI facilities (Gaussian distance decay, power distance decay, piecewise distance decay). Finally, under optimal distance decay, the MGWR model is used to investigate how the built environment influences metro ridership. The results show the following: (1) The Gaussian distance-decay function improves the goodness of fit of the regression model, resulting in an 11.25% increase in the R² value when compared to the model without a distance-decay function. (2) During morning peak hours, apartment and office density significantly impacts ridership. The proposed research framework is conducive to improving the accuracy of the metro station ridership regression model. Moreover, it facilitates the formulation of targeted strategies for the renewal of the built environment by government managers and planners. Full article

(This article belongs to the Special Issue New Trends in Built Environment and Mobility)

21 pages, 1314 KiB

Open AccessArticle

The Influence of Geometry of Helical Anchors on Frost-Heave Performance in Seasonal Frozen Regions

by Ji Zhang, Yan Liu, Zhonghua Lv, Dongxue Hao, Xinying Zhao, Haoyu Wang, Yexian Shi and Yuhang Zhang

Buildings 2025, 15(10), 1685; https://doi.org/10.3390/buildings15101685 - 16 May 2025

Abstract

Helical anchors are deep foundation systems that offer high uplift capacity due to the increased interaction area between the helix and surrounding soil, thus exhibiting strong potential for resisting frost jacking in cold-region engineering. The influence of helical anchor geometry on frost heave [...] Read more.

Helical anchors are deep foundation systems that offer high uplift capacity due to the increased interaction area between the helix and surrounding soil, thus exhibiting strong potential for resisting frost jacking in cold-region engineering. The influence of helical anchor geometry on frost heave behavior remains a critical yet insufficiently understood factor in engineering designs. Accordingly, this study conducts experimental and numerical investigations to evaluate the effects of helix number, helix diameter, helix spacing, and freeze−thaw cycles on frost jacking and thaw-induced settlement. The results indicate that the frost jacking and residual displacement after thawing gradually decrease with increasing freeze−thaw cycles and tend to stabilize after more than three cycles. Numerical simulations show that the residual displacements for full-scale anchors range from 12% to 33% of the peak frost jacking. Anchors with a greater number of helices demonstrate improved resistance to frost jacking when the uplift capabilities are comparable. When the helix spacing ranges from 2D to 6D (where D denotes the helix diameter), the double-helix anchor with 2D spacing exhibits the highest stability during freeze−thaw cycles, followed by the anchor with 3D spacing. However, the anchor with 2D spacing yields the lowest uplift capacity under unfrozen soil conditions. Anchors with a helix spacing of 2D to 3D are recommended for resisting freeze–thaw effects, provided that this configuration does not significantly reduce the uplift capacity. Full article

(This article belongs to the Section Building Structures)

16 pages, 258 KiB

Open AccessArticle

Strategic Interaction in the Supply of Affordable Housing Construction Land: Evidence from China’s Cities

by Zhen Wang, Haiyong Zhang, Siyu Liu and Jie Chen

Buildings 2025, 15(10), 1684; https://doi.org/10.3390/buildings15101684 (registering DOI) - 16 May 2025

Abstract

This study examines strategic interaction effects in the supply of affordable housing construction land among Chinese urban governments. Existing studies have predominantly examined China’s subsidized housing land supply from a vertical intergovernmental perspective, whereas this study investigates strategic interaction effects in municipal governments’ [...] Read more.

This study examines strategic interaction effects in the supply of affordable housing construction land among Chinese urban governments. Existing studies have predominantly examined China’s subsidized housing land supply from a vertical intergovernmental perspective, whereas this study investigates strategic interaction effects in municipal governments’ land allocation for subsidized housing from a horizontal and regional viewpoint. By conducting spatial econometric analysis on panel data from 278 prefectural-level cities in China (2010–2019) and constructing multiple patterns of intergovernmental strategic interactions based on diverse spatial weight matrices, this study provides robust evidence of strategic interactions and their underlying mechanisms among Chinese municipal governments in allocating construction land for affordable housing. The study reveals that Chinese urban governments exhibit positive strategic interactions in the supply of affordable housing construction land. This collaborative pattern demonstrates convergent (rather than divergent) supply strategies among horizontal intergovernmental relationships, further indicating a cross-regional equalization trend in China’s affordable housing provision. Two latent mechanisms drive these strategic interactions: spillover effects from intra-provincial political competition and the proactive agency effects of key local leadership figures. Therefore, China’s central government must fully account for the strategic interactions among municipal governments in allocating construction land for affordable housing. It is essential to establish adaptive regulatory mechanisms for regional cities’ supply of such land and ensure healthy, sustainable allocation of urban construction land for affordable housing through targeted interventions. Full article

(This article belongs to the Special Issue Real Estate, Housing and Urban Governance)

23 pages, 1475 KiB

Open AccessArticle

The Comprehensive Energy and Exergy Analysis on Thermal-Catalytic-Type and Thermal-Catalytic–Photovoltaic-Type Trombe Walls

by Weikai Wang, Niansi Li, Wei Wei, Jie Ji and Bendong Yu

Buildings 2025, 15(10), 1683; https://doi.org/10.3390/buildings15101683 - 16 May 2025

Abstract

The aim of this study is to address the lack of comprehensive analysis methods for multi-functional Trombe wall systems. The objective is to establish an integrated evaluation system that assesses thermal, purification, and power generation performance. This study introduces a novel multi-objective analysis [...] Read more.

The aim of this study is to address the lack of comprehensive analysis methods for multi-functional Trombe wall systems. The objective is to establish an integrated evaluation system that assesses thermal, purification, and power generation performance. This study introduces a novel multi-objective analysis method coupling energy and exergy efficiency for three types of Trombe wall structures: traditional, thermal-catalytic (TC), and TC–photovoltaic (TC-PV). This study simultaneously monitors heat transfer, formaldehyde degradation, and photovoltaic power generation performance. A key novelty is the introduction of a quantitative index for “purification efficiency” and the revelation of the co-evolution law between PV (photovoltaic) coverage and the three types of efficiency for the first time. This study evaluates three cases: traditional, TC, and TC-PV Trombe walls. The results show that the thermal efficiencies of the three Trombe walls are 47.2%, 41.9%, and 51.7%, respectively, with corresponding thermal exergy efficiencies of 0.59%, 0.49%, and 0.63%. The TC and TC-PV Trombe walls achieve purification efficiencies of 57.0% and 53.0% and purification exergy efficiencies of 2.53% and 2.42%, respectively. The TC-PV Trombe wall has electrical and electrical exergy efficiencies of 16.0% and 12.84%, respectively. System structure optimization analysis indicates that the system achieves the best exergy efficiency when the solar irradiation is 400 W/m² and the air channel thickness is 0.05 m. Additionally, the purification exergy efficiency increases with higher formaldehyde concentrations, while thermal, purification, and electric exergy efficiencies all increase with greater PV coverage. Exergy loss analysis reveals that the TC layer and heat-absorbing plate are major sources of loss. Therefore, developing catalytic materials with high absorptivity and high catalytic activity could enhance the system’s exergy efficiency. Full article

(This article belongs to the Section Building Energy, Physics, Environment, and Systems)

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