Buildings, Volume 14, Issue 5 (May 2024) – 153 articles

Current challenges in collecting and analyzing subway vibration data include the absence of standardized data collection methods, limitations in data analysis techniques, and an unclear understanding of the effects of geological conditions on vibrations. This study investigated vertical vibrations of tunnel walls and the ground above tunnels under different geological conditions of soft soil and rock strata at horizontal distances of 0, 15 m, and 30 m from the tunnel center line during train passages. The collected data underwent Fourier transformation and 1/3 octave processing to extract spectral characteristics and analyze transmission losses across different frequency bands. Our findings revealed two vibration peaks in the transmission process for both soft soil and rock formation geology. Specifically, high-frequency vibrations in soft soil experienced greater attenuation when transmitted from the tunnel wall to the ground at 0 m, while low-frequency vibrations in rock formations showed greater attenuation. We also observed a vibration amplification phenomenon at 15 m under soft soil geology conditions. Although low-frequency vibrations below 12.5 Hz showed slight attenuation within a 30 m test distance under both geological conditions, vibrations above 40 Hz experienced significant attenuation. These results offer valuable insights for reducing vibrations in subway superstructures and planning subway lines under diverse geological conditions. Furthermore, this study serves not only as a basis for mitigating vibrations in metro spans and designing metro lines in various geological contexts but also establishes a scientific foundation for future research. Full article

Over the past decade, the concept of a circular economy has increasingly gained attention as a framework for guiding businesses and policymakers. Given its significant environmental impact, the building industry plays a pivotal role in the transition toward a circular economy. To address this, our review proposes a bio-based building material, specifically straw bale, which elaborates on the circularity of bio-based buildings based on the 3R principles of a circular economy: reduce, reuse, and recycle. In terms of the “reduce” principle, straw-bale buildings can reduce construction waste, the environmental impact, energy requirements, and carbon emissions. Regarding the “reuse” principle, straw-bale buildings utilize agricultural waste resources and are easily disassembled due to their prefabrication. As for the “recycle” principle, straw-bale buildings can undergo physical, biological, and biochemical conversion processes (thermochemical conversion), yielding both wooden composite boards and potential biogas and biomass fuels for electricity and heating. This study evaluates the contribution of straw packaging construction and the use of straw as a raw material, using the 3R principles to determine future research opportunities for the construction industry to achieve a circular economy. The results of this study offer circular economy solutions and interdisciplinary research insights for researchers and practitioners interested in the building environment. Full article

This study aimed to assess the viability of utilizing lime–fly ash (LF) and red mud (RM) in the modification of silty soil (LF-RMS) for subgrade filling. The primary objective of this research was to analyze the mechanical characteristics and examine the curing mechanisms associated with said modified materials. Different curing times were utilized in the analysis of mechanical properties (e.g., via unconfined compression testing), microstructure (via scanning electron microscopy, X-ray diffraction, and thermogravimetric-differential thermal analysis), and environmental indices (via assessment of corrosivity, heavy metal concentration, and radioactivity) with various dosages of red mud (D_RM) and Lime–fly ash (D_LF). Analyses of the curing mechanisms, failure modes, microstructures, and degrees of environmental impact associated with LF-RMS were also undertaken. The tests indicated that the unconfined compressive strength (UCS) exhibited an initial increase followed by a decrease as the D_RM and D_LF levels increased. Additionally, the strength of LF-RMS increased with an increase in curing time. It is worth noting that the specimen composed of 20% LF and 23% RM (D_20%LF+23%RM) demonstrated a maximum UCS value of 4.72 MPa after 90 days of curing, which indicates that it has the strongest ability to resist deformation. The strength of the specimen cured for 90 days was 1.4 times higher than that of the specimen cured for 7 days (1.97 MPa). Furthermore, the toxic concentration and radionuclide index of LF-RMS were significantly reduced compared to those of pure RM. The overall concentration of heavy metals in the D_20%LF+23%RM specimen decreased by more than 60% after curing for 28 days. The internal irradiation index and the external irradiation index decreased by 1.63 and 1.69, respectively. The hydration products in LF-RMS play a key role in the solidification of heavy metals, and the alkaline environment provided by RM also contributes to the precipitation and replacement of heavy metals. In this study, red mud, fly ash and lime were used to modify silty soil. The central tenets of sustainable development may be achieved through the reuse of RM as a road filler. Full article

To reduce the negative impact on the environment, architects, designers, and construction companies need to find and apply eco-friendly and sustainable building solutions. Due to its renewable nature and numerous advantages, timber has become an attractive substitute for steel and concrete in both residential and non-residential construction projects. However, timber application in the construction of grocery stores is a relatively new concept. The purpose of this research is to propose three alternative timber-based structural systems for a grocery store in Lithuania and to select the most efficient option based on multi-criteria decision-making methods. Three alternative glued laminated timber (glulam) structural systems—the glulam column and truss system, the glulam three-hinge frame system, and the glulam column and double-tapered beam system—were designed. The systems were evaluated against ten criteria, reflecting structural properties, cost efficiency, assembling complexity, and aesthetics. Multiple-criteria assessments by the COmplex PRoportional ASsessment (COPRAS) method and simple additive weighting (SAW) method revealed that the best-performing alternative is the glulam column and double-tapered beam system due to the lower cost of load-bearing structures, the smaller quantity of required steel details and fittings, and the highest maximum utility ratio according to serviceability limit states compared to other alternatives. Full article

Low-carbon fly ash concrete is one of the hottest research topics in the concrete industry. This study proposes a design method for low-carbon fly ash concrete that systematically considers strength, form removal time, and carbonation durability life. The basic steps of this method are as follows: First, based on the experimental results, the strength development formula of fly ash concrete using different mix ratios and different aging periods is obtained through regression. The adopted carbonation depth calculation formula can be used to consider the influence of the curing time and mix ratio on carbonation depth. Second, through the analysis of design cases, the dominant factors in the design of low-carbon fly ash concrete are clarified. For example, strength dominates, demolding time dominates, or carbonation durability dominates. If the concrete is removed from the formwork early, the carbonation resistance is very weak, and a large amount of cementitious material is required in order to meet the carbonation durability requirements. Appropriately extending the removal time of the concrete form can enhance the carbonation durability, reduce the content of cementitious materials, and achieve the goal of low-carbon design. In short, the method proposed in this study can be used as a general method for low-carbon fly ash concrete design, and this method can be extended for use in different countries and regions. Full article

Prefabricated panel-assembled wall systems, comprising a confining frame and infill lightweight panels of autoclaved aerated concrete (AAC), are widely employed in framed structures. Different from studies on a main frame with infill walls, this study aimed to explore the seismic performance of partition walls, which were fabricated with AAC panel-assembled walls and located outside of the main frames. Two full-scale specimens, one with a door opening and the other without, were constructed and cyclic loading tests were executed to examine the failure modes, hysteresis characteristics, envelope curves, ductility, strength and stiffness degradation, as well as energy dissipation capacity of the AAC panel-assembled walls. Additionally, a restoring-force model for the panel-assembled walls was developed and a method for predicting the lateral load-bearing capacity of the AAC panel-assembled walls was proposed. The findings indicated that the panels enhanced the system’s lateral resistance, energy dissipation capacity, and deformation capability. The door frame increased the initial stiffness, peak lateral load and energy dissipation capacity of the AAC panel-assembled wall compared to the wall without a door frame. Compared to the specimen without a door frame, the peak lateral load of the specimen with a door frame increased by 19.7–30.1%. The deformation capacity of the panel-assembled walls aligned with the requirements for concrete framed structures. Full article

The bond–slip behavior of the steel–concrete interface is critical in reinforced concrete (RC) structures since the bond action is the mechanism that ensures the two materials work in co-operation. However, there is little research considering the bond–slip behavior in massive ring-type reinforced concrete (MRRC) structure bearing analyses due to the complexity of modeling the interfacial behavior. Hence, the influence of the bond–slip behavior on the bearing characteristics of MRRC structures remains unclear. Steel-lined reinforced concrete penstock is such an MRRC structure, composed of steel liner and reinforced concrete and commonly used in diversion pipelines. This paper aims to explore the bearing characteristics considering the bond–slip behavior in the composite penstock by using a promising numerical method, the cohesive zone model. Three interface models were proposed to represent the different interaction conditions at the steel–concrete interface. Moreover, a sensitivity analysis was performed to study the impact of the bond strength on the bond performance and structural behavior. The simulation results showed that the prediction results (steel stress and crack process) considering the bond–slip behavior were in good agreement with the experimental results. The steel stresses near the cracks were smaller and more uniform after considering the bond–slip behavior, since the stresses were no longer concentrated on the crack but distributed in an area near the crack. However, the steel stress differences in these models were within 10%, which means that the bond performance had a limited effect on the structural safety design. The crack widths were greatly influenced by the bond conditions, and the maximum crack width (0.461 mm) in poor conditions was beyond the limiting value (0.3 mm). Consequently, bond–slip behavior must be paid more attention in durability design. Full article

The localization results of acoustic emission (AE) events can reflect the location and pattern of burst-prone rock failures. However, event localization heavily depends on the quality of the original waveform of the sensor. Therefore, this study analyzed the AE waveform of a rock sample under compression to evaluate its failure localization and quality. From the research results, it could be seen that the initial failure was relatively calm, with clear take-off points, which can be better used for accurate AE event positioning. However, the later failure was severe, causing the take-off points of most sensors to be very unclear, and positioning methods that rely on take-off points cannot be used for positioning, let alone simply using the positioning results of the built-in software. This research result reminds researchers who use AE signals for event localization to first examine the quality and status of the original waveform, providing a basis for obtaining accurate localization results, in order to further accurately study the subsequent failure patterns. The above facts indicate that the initial failure is small and scattered, while the later failure is large and concentrated, with certain fractal characteristics. Full article

In order to quantitatively study the influence of the weakening of the disconnectable coupling joint (DC joint) on the retaining structure, the pre-axial force retention performance of the steel support, the axial force of the steel support, the horizontal displacement of the diaphragm wall, and the ground settlement around the foundation pit were monitored during the construction of the foundation pit. The evolution process of the monitoring data was analyzed, and the corresponding numerical model verified by the monitoring data was established. The influence of the yield load of the DC joint, the initial compression stiffness, and the weakening of the pre-axial force on the stability of the retaining structure was studied by numerical simulation. The results show that the pre-axial force of steel support is only 67% of the design value when the soil below is not excavated within 24 h. The DC joint has a significant weakening effect on the steel support, which is unfavorable for the stability control of the foundation pit retaining structure. The pre-axial force and initial bending stiffness have a great influence on the stability of the retaining structure. When the yield load is not lower than that of the row piles, the DC joint has no effect on the stability of the retaining structure. This model can predict and analyze the deformation trend under different working conditions to a certain extent, providing certain reference value for safety plans during construction. Full article

This paper focuses on the experimental investigation of the axial load capacity of CFT (concrete-filled steel tube) columns under actual construction conditions during building reconstruction. A total of four samples were loaded up to failure. The varied parameters were the column length and absence/presence of the concrete infill within the steel tube. Further, the analysis is extended to developing a numerical model in the finite element-based software ABAQUS version 6.9. This numerical model includes material and geometrical nonlinearities and was validated with the experimental results. The contribution of the concrete core to the column capacity and the concrete core confinement effect are discussed. Finally, the column capacity was calculated according to several design codes: the Eurocode 4 with and without considering the confinement effect, American specifications, Australian standards, the American Institute of Steel Construction, and the Architectural Institute of Japan. The Eurocode 4 considering the confinement effect provides the closest results to those obtained in the tests. Full article

The practical application of BFRPB (Basalt Fiber-Reinforced Polymer Bars) as a support structure in foundation pit and slope engineering is relatively under-researched. The indoor tensile test presented in this paper is carried out on the bond between BFRPB and different labelled concrete. The mechanical characteristics of BFRPB, the failure characteristics, and the load-carrying capacity were analyzed. The results of this study demonstrate that the normal section stress of concrete cylindrical components with BFRP has a good linear relationship and supports the rationality of the flat section assumption. In circular reinforced concrete BFRP structures, the failure of the pile load occurs in four phases, and the cracking load is in the range of 51% to 67% of the normal yield load. The main bars increase in strain with load but become attenuated in the compression zone. The deformation of the main bars increases with the load but becomes muted in the compression zone. Based on the method of calculating the load-carrying capacity of GFRP-reinforced RC piles and the normal limit load-carrying moment obtained from in-door tests, the bending moment correction coefficient in the calculation formula for the load-carrying capacity of BFRP-reinforced RC piles was then obtained. Full article

Similar to living complex systems, cities are composed of a huge number of interacting parts, each with its specific properties, rhythm, etc., that, by means of self-organization, give rise to a functioning complex system. A major challenge is thus to follow the self-organized adaptation process by which the huge number of diverse parts coordinate their action and behavior into a coherent whole. Coordination dynamics, the science of coordination, elaborates on this issue, showing how patterns of coordination form, adapt, persist and change in living things. Recent studies on cities and complexity exposed that human agents differ from other living things in that they adapt not only through behavior but also through the construction of artifacts, thus giving rise to hybrid complex systems (HCSs) and to cities as such. This entails a new challenge regarding the various aspects and roles of artifacts in coordination dynamics. This study introduces the notions of hybrid complex systems and coordination dynamics and then focuses on one aspect that concerns coordination in cities: the ways the artificial urban landscape participates in coordinating the dynamics between the human urban agents. Full article

Helical piles are advantageous alternatives in constructions subjected to high tractions in their foundations, like transmission towers. Installation torque is a key parameter to define installation equipment and the final depth of the helical pile. This work applies machine learning (ML) techniques to predict helical pile installation torque based on information from 707 installation reports, including Standard Penetration Test (SPT) data. It uses this information to build three datasets to train and test eight machine-learning techniques. Decision tree (DT) was the worst technique for comparing performances, and cubist (CUB) was the best. Pile length was the most important variable, while soil type had little relevance for predictions. Predictions become more accurate for torque values greater than 8 kNm. Results show that CUB predictions are within $\left[0.71,1.59\right]$ times the real value with a 95% confidence. Thus, CUB successfully predicted the pile length using SPT data in a case study. One can conclude that the proposed methodology has the potential to aid in the helical pile design and the equipment specification for installation. Full article

Construction prices rose rapidly during 2020 and 2021, making it almost impossible for contractors to adhere to agreed contract prices. For this reason, there was a request from contractors to adjust the contract price after signing a contract for work. During the implementation of the construction contracts, they were unable to comply with the fixed contract price. Forecasting the development of price indices could solve this problem by creating a reserve that would limit the adjustment of the contract price and the contractors’ withdrawal from the contracts. The forecast could be enshrined in the contractual conditions before the start of construction, which would eliminate the risk of changing the agreed contract price for the investor and the possible occurrence of additional work. Data from statistical offices were used to create the price index forecast. In this article, four methods were used in the search for a more accurate forecast: regression analysis, exponential smoothing, the naïve method, and the Autoregressive Integrated Moving Average (ARIMA) model. From these methods, the most appropriate method was selected by multi-criteria decision-making, which was subsequently verified with actual published price index data. The main goals of this study are to determine the most suitable prognostic method for forecasting the development of the prices of construction materials and work and then comparing the forecasted data with the actual published data of statistical offices in the countries of Central Europe. Full article

The preservation and reuse of historical alley spaces infuse these areas with renewed vitality, which holds significant importance for the direction of preservation and restoration efforts in historical districts. This paper focuses on Jinyu Alley in Quanzhou and identifies a study targeting tourists for the protection and reuse of historical alley spaces. Through preliminary research and interviews, a system of evaluation indicators for urban historical alley spaces post-usage was established using a factor analysis, extracting five main components: historical context, neighborhood space, commercial environment, supporting facilities, and operational management. Additionally, a modified importance–performance analysis (IPA) method was employed to conduct a quadrant analysis on tourist satisfaction evaluation indicators. Transformation quadrant distribution maps of various evaluation indicators reveal dissatisfaction among tourists with certain aspects of supporting facilities, the commercial environment, and neighborhood space. Relevant departments should prioritize improvements in dining quality, business variety, neighborhood traffic connections and transformations, neighborhood space form and scale, landscape greening, environmental elements, parking availability, and trash bin density for future enhancements. Finally, based on the results of tourist satisfaction surveys and information gathered from interviews with a minority of residents, a more inclusive and sustainable strategy for the protection and reuse of historical alley spaces is formulated. Full article

The integration of waste materials in extrudable cement mixtures has the potential to make the construction industry more sustainable by reducing carbon footprints and developing eco-friendly materials. This along with advancements in 3D concrete printing (3DCP) provides engineering and architectural benefits by reducing material waste and costs. In this paper, the impact of waste incorporation on properties of mortar and concrete is examined. The use of waste materials, such as pumice, coal slag, agricultural lignocellulosic residues, and recycled rubber tyres, to improve thermal insulation and durability of cementitious composites is discussed. In addition, the incorporation of air-entraining admixtures with surfactant activity is explored for their indirect effect on thermal behaviour, pore size reduction, and enhancement in concrete properties. This review includes important topics such as a strength resistance to freezing and thawing, fire resistance, plasticising effect, and delay in cement hydration. These findings highlight the benefits of using diverse waste materials in construction, providing a multidimensional approach to waste management, cost optimization, and enhanced construction materials in the context of 3DCP. Full article

Efficient carbon emission reduction technologies in buildings are necessary for achieving the “Dual carbon” goal in China. In this study, a comprehensive evaluation model is proposed to assess the effect of carbon emission reduction based on the analytic hierarchy process–entropy weight–coefficient of variation model which takes newly built residential buildings in Zhuzhou City as the research object. The results show that the preferred materials for the roof and exterior walls of the building’s envelope structure were flame-retardant extruded polystyrene boards, and porous shale bricks were preferred as the main materials for the exterior walls. In addition, the rooftop solar photovoltaic system and energy-saving air conditioning technology were suitable in terms of being renewable and were better utilized. In the end, carbon emissions were significantly reduced when using the building decarbonization technologies. This study provides a new reference for choosing materials and technologies for the design of residential buildings in Hunan Province and even other regions with hot summers and cold winters. Full article

Conventional methods for designing retaining structures are not applicable to asymmetric excavation or deformation-based designs. This study proposes a quadruple-line displacement-dependent earth pressure coefficient model. Based on the proposed model, an analytical solution was developed to facilitate the deformation-based design of the asymmetric length of retaining walls propped at the crest. Furthermore, the effects of the soil internal friction angle, strut stiffness, excavation asymmetry level, and deformation control value on the embedment ratio (R_e) of retaining walls were investigated. The results showed that R_e determined by the classical equivalent-beam method is unsafe due to its basis on the ultimate-state earth pressure theory. The R_e value of the shallower side exhibited greater sensitivity to asymmetric excavation than that of the deeper side. The retaining structure’s required R_e decreased with an increase in the excavation asymmetry level. The required R_e on either side of the retaining structure decreased as the deformation control values increased. The controlled deformation had a more obvious effect on the R_e value of the retaining structure on the deeper side. The proposed method can be used for the deformation-based design of asymmetric wall lengths of retaining structures propped at the crest, considering the different excavation depths on both sides. Full article

(1) This paper, based on the characteristics of complex steel structures as well as difficult points in the process of their detailed design, introduces the product design concept of DfMA (Design for Manufacturing and Assembly) from the manufacturing industry and studies the detailed design method of BIM-FEM model conversion. The BIM software Revit (2020) is used as the basis for the BIM detailed design of the project, which achieves the purpose of rapid modeling and provides a detailed design model basis for finite element analysis. (2) Utilizing the Revit API and C# for secondary development as the technical means, this approach involves converting the geometric entity model described by CSG-Brep into an APDL stream. This creates an interface with the finite element analysis software ANSYS (12.0) to implement the detailed design of BIM-FEM model conversion, optimizing the algorithm for converting complex analysis models that require high precision for special-shaped steel structures. (3) This research addresses issues such as the disconnection between the design, manufacturing, and construction of special-shaped steel structures, providing support for design decisions. Moreover, it enhances the detailed design method by improving the standardization of special-shaped components under the condition of design diversity. (4) These studies provide sustainability for engineering design, manufacturing, and construction projects, enabling the maximization of benefits and product lifecycle management (PLM) through these projects. (5) Finally, a case study analysis was conducted on the Wuhan City New Generation Weather Radar Construction Project, designed by the Central South Architectural Design Institute (CSADI), to verify the detailed design of BIM-FEM model conversion. This proved the scientific validity, practicality, and necessity of this research. Full article

Hollow structures reduce weight without compromising load-bearing capacity and are widely used. The new Glass-Fiber-Reinforced Polymer high-strength thin-walled inner mold simplifies internal cavity construction and boosts structural performance. This study first investigates the influence of a GFRP high-strength thin-walled circular tube on the cross-sectional load-carrying capacity of hollow slabs. Then, a formula for the bending load-carrying capacity of the section under the action of the tube is derived. The results indicate that when the height of the concrete compression zone meets certain conditions, GFRP high-strength thin-walled circular tubes can improve the ultimate load-carrying capacity of the hollow floor slabs. In order to achieve a more economical design, the bending moment modification of a GFRP high-strength thin-walled circular tube of a continuous slab was studied. Research has found that the bending moment modulation limit for a continuous slab is 35.65% when it is subjected to a load of $P_u=24 \mathrm{k}\mathrm{N}$. Experimental analysis has shown that the results are generally consistent with the calculations. In practical engineering, the application of a GFRP high-strength thin-walled circular tube of continuous slabs has limitations. Therefore, this study investigated a GFRP high-strength thin-walled honeycomb core slab and found that its ultimate load-bearing capacity is greater compared to waffle slabs. In addition, the stress performance of the GFRP high-strength thin-walled honeycomb core internal mold is superior, making it more promising for practical applications. Full article

Irregularity in the plane layout of a building structure and the vertical discontinuity of lateral resistance components could lead to torsion and result in the brittle failure of a structure. According to the characteristics of the conventional island main building of nuclear power plants, this paper focuses on the conventional island main building of the CAP1400 nuclear power plant (NPP) in Shidaowan as the research object. A prototype structure model of the main building was developed using ABAQUS software. The seismic response of the structure under multidimensional ground motion was studied by inputting the X-direction and Y-direction translational and torsional components of ground motion in ABAQUS. The results demonstrate that the overall transverse displacement of the structure under bidirectional ground motion was significantly higher than that under unidirectional earthquakes, which was about 20%. Under a multidimensional frequent earthquake, the transverse displacement of the structure increased by about 13% on average compared with that under a bidirectional earthquake; the longitudinal increase was the largest, at about 28%. Finally, the lateral displacement of each layer of the steel-reinforced concrete (SRC) frame-bent main building structure with few walls proposed in this article decreased by an average of about 17% compared to the traditional SRC frame-bent main building structure. The longitudinal displacement was reduced by about 14% compared to the traditional SRC frame-bent main building structure. Full article

Forecasting construction spending is important for civil engineering practitioners to make business decisions. Currently, the main body of forecasting literature pertains exclusively to aggregate construction investment, such as total construction spending (TTLCON), private construction spending, or residential construction spending. But type-specific construction spending, such as that for education, healthcare, and religion, had yet to be explored using forecasting techniques. This case study presents a viable procedure by which aggregate and type-specific non-residential construction can be forecasted. The procedure that involves the use of the Granger causality test and the Vector Autoregression (VAR) model proved to be able to provide an accurate forecast pre-COVID-19, with some accuracy even during the COVID-19 pandemic period. Lessons learned include the following: (1) effort should be diverted towards model interpretation, as the impulse–response trial yields results conforming to current well-established empirical evidence; (2) a type-specific approach should be adopted when analyzing construction spending, as different types of construction spending react differently to potential indicators; and (3) complex models incorporating multiple indicators should be used to generate a forecast, as a complex model has a higher chance of containing parameters explanatory of the target variable’s features during the testing period. Full article

By comparing different settlement forecast methods, eight methods were selected considering the creep of marine soft soils in this case study, including the Hyperbolic Method (HM), Exponential Curve Method (ECM), Pearl Growth Curve Modeling (PGCM), Gompertz Growth Curve Modeling (GGCM), Grey (1, 1) Model (GM), Grey Verhulst Model (GVM), Back Propagation of Artificial Neural Network (BPANN) with Levenberg–Marquardt Algorithm (BPLM), and BPANN with Gradient Descent of Momentum and Adaptive Learning Rate (BPGD). Taking Lingni Seawall soil ground improved with prefabricated vertical drain-assisted staged riprap filling as an example, forecasts of the short-term, medium-term, long-term, and final settlements at different locations of the soft ground were performed with the eight selected methods. The forecasting values were compared with each other and with the monitored data. When relative errors were between 0 and −1%, both the forecasting accuracy and engineering safety were appropriate and reliable. It was concluded that the appropriate forecast methods were different not only due to the time periods during the settlement process, but also the locations of soft ground. Among these methods, only BPGD was appropriate for all the time periods and locations, such as at the edge of the berm, and at the center of the berm and embankment. Full article

This study reviews worldwide wetland park research from 1996 to 2022. A bibliometric analysis is conducted on 591 wetland park studies indexed in the Web of Science and Scopus databases. The study utilizes CiteSpace and VOSviewer tools to visualize and explore influential research focuses, themes, directions, and countries. The citation burst indicates that from 1996 to 2022, research on wetland parks transited from exploring basic community structures to complex ecosystem service assessments and the formulation of management strategies. Furthermore, over the past three years, wetland park research has seen a significant surge in studies investigating water quality, ecosystem services, and spatiotemporal analysis. Notably, the three most frequent keywords in research on wetland parks were China, South Africa, and biodiversity. These keywords reflect regions that enhance biodiversity via wetland parks. The spectral-clustering algorithm identifies carbon sequestration as a research focus, highlighting the vital role of wetlands in the carbon cycle. Most authors work in developed countries’ institutions, but some are from developing countries like China, South Africa, and India. The findings suggest that economic development is crucial in wetland park construction and significantly influences related research. Developed countries may offer more PhD positions to developing countries’ researchers in the field and raise their awareness about wetland conservation. Given the holistic requirements of wetlands, this research recommends that educators should adopt an interdisciplinary approach in the future when nurturing wetland staff. Additionally, the study maps out the primary areas of interest in wetland park research, including environmental science, ecological economics, forestry, wetlands, tourism, and management. New artificial intelligence and digital technologies should be developed for wetland park research. This study fills a research gap: quantitative and visualized knowledge-mapping and bibliometrics on wetland parks are scarce. Additionally, no previous study has explored the relationship between wetland park research and the economic development of countries. Full article

In order to further improve the technical advantages of lightweight prefabricated concrete stairs, a kind of prefabricated stair system using a special-shaped hollow landing slab was proposed. Based on the detailed structural composition display, the design method for the main components (prefabricated flight and special-shaped prefabricated hollow landing slab) was proposed and a design application example was provided. Furthermore, specialized experimental and numerical simulation studies were conducted on the key component—the special-shaped prefabricated hollow landing slab. The research results indicated that this new kind of lightweight prefabricated concrete stairs using a special-shaped prefabricated hollow landing slab has reasonable construction, an effective design method, a clear force transmission mechanism, moderate component weight, and high transportation and installation convenience. Full article

Asphalt pavements are prone to cracking in low-temperature environments, and microwave heating (MH) can heal the cracks effectively. This research mainly investigates the different MH effects on the self-healing properties of asphalt mixtures. With this objective, the three-point splitting test is conducted to generate the cracks. A microwave oven is employed to heat the samples, and a thermal camera measures the surface temperature. Results indicate that heating power and time show a positive linear correlation with healing efficiency, and the HI of the samples can reach over 80%. The HI of the samples decreases with the heating cycle, but the sample with reasonable power and time still has a HI higher than 70% after 5 cycles. The temperature peaks on thermal images indicate that uneven heating exists during heating, but the heating uniformity is within an acceptable range. The healing efficiency level (HEL) suggests that asphalt mixtures have very low inefficient healing behavior if the heating time is below 45 s, but HEL can reach 86.14% at 700 W after 60 s. Furthermore, although the HI of strength shows ideal results, the recovery of other crack parameters, including stiffness, fracture energy, flexible index, and crack resistance index, are not satisfactory. Full article

To effectively reduce building energy consumption, a novel full fresh air system with a heat source tower (HST) and a borehole heat exchanger (BHE) was proposed for space cooling and dehumidification in this paper. The cooling system only adopts geothermal energy to produce dry and cold fresh air for space cooling and dehumidification through the BHE and HST, which has the advantage of non-condensate water compared to BHE systems integrated with a fan coil or chilled beam. Based on the established mathematical model of the cooling system, this paper analyzed the system characteristics, feasibility, operation strategy, energy performance, and cost-effectiveness of the proposed model in detail. The results show that the mathematical model has less than 10% error in estimating the system performance compared to the practical HST−BHE experimental set up. Under the specific boundary conditions, the cooling and dehumidification capacity of this system increases with the decrease in the air temperature, air moisture content, and inlet water temperature of the HST. The optimal cooling capacity and the system COP can be achieved when the air–water flow ratio is at 4:3. A case study was conducted in a residential building in Shenyang with an area of about 1800 m². It was found that this system can fully meet the cooling and dehumidification demand in such a residential building. The operation strategy of the cooling system can be optimized by adjusting the air–water flow ratio from 4:3 to 3:2 during the early cooling season (7 June–1 July) and end cooling season (3 August–1 September). As a result, the average COP of the cooling system during the whole cooling season can be improved from 6.1 to 8.7. Compared with the air source heat pump (ASHP) and the ground source heat pump (GSHP) for space cooling, the proposed cooling system can achieve an energy saving rate of 123% and 26%, respectively. Considering that the BHE of the GSHP can be part of the proposed HST−BHE cooling system, the integration of the HST and GHSP for space cooling (and heating) is strongly recommended in actual applications. Full article

Energy efficiency is a principle of architectural design that reduces environmental impact. Generative design can offer alternative options to improve energy efficiency in buildings, but significant gaps exist in the application due to accessing complex knowledge. This study aimed to explore publications on generative design and energy efficiency in buildings and identify generative methods for energy efficiency topics. This study conducted a systematic review using the PRISMA methodology in December 2023 by searching publications from databases including Scopus, Google Scholar, and Thai Journals Online. Descriptive analysis examined 34 articles, showing the publication year, source, and citations. Comparative qualitative and descriptive analysis identified generative methods. Publications are increasing over time, and further growth is expected related to the accessibility of computational design and practical applications. Tools and frameworks demonstrated reduced energy usage compared to prototypes or traditional design approaches. The most studied is thermal performance, which was reduced by 28%. Energy performance achieved up to a 23.30% reduction, followed by others and daylighting. In addition to single-topic studies, there are also studies with multiple topics. Evolutionary algorithms are standard. Parametric search strategies have increased. Exploration reveals rule-based and mixed methods. Machine learning and AI garner attention. Full article

Thermal comfort is a complex issue in the built environment due to the physiological and psychological differences of each individual in a building. There is a growing worry over the environmental implications of energy use as a result of the warming of the global climate and the growth in the number of instances of extreme weather events. Many review articles have been written, but these reviews have focused on a specific aspect of occupant behavior and thermal comfort. To research the trends of thermal comfort and energy, this research adopted mixed reviews, i.e., quantitative and qualitative, to understand the state-of-the-art factors affecting the thermal comfort of occupants concerning energy, different occupant modeling approaches, functions, and limitations. The in-depth qualitative discussion provides deeper insights into the impacts of occupant behaviors, factors affecting thermal comfort, and occupant behavior modeling approaches. This study classified occupant behaviors into five categories: occupant characteristics, perceptions of the occupant, realistic behaviors, heat gain, and occupant interactions with the system. It also went further to classify the factors affecting the thermal comfort of users based on past works of literature. These include structural, environmental, and human factors. It was concluded that factors that have the most significant impact on energy are human, structural, and environmental factors, respectively. In addition, most of the occupant behavior modeling approaches that have been used in past studies have pros and cons and cannot accurately predict human behaviors because they are stochastic. Future research should be conducted on thermal comfort for different building functions by examining the varied activity intensity levels of users, especially in educational or commercial buildings. Additionally, a proper investigation should be carried out on how thermal insulation of structural members influences thermal comfort. These should be compared in two similar buildings to understand occupant behavioral actions and energy consumption. Full article

The primary motivation of this study is to develop a compound intensity measure (IM) to evaluate ground motion damage potential based on principal component analysis (PCA) and canonical correlation analysis (CCA). To illustrate this, this study examines the correlation among intragroup IMs and intergroup IMs, as well as the correlation between various IMs and response variables. A compound IM, which can be obtained by a linear combination of ten IMs in the log-scale, is utilized to measure the ground motion damage potential. Elastoplastic, bilinear and hysteretic models are utilized to determine peak deformation and hysteretic energy as the response variables of Single-Degree-of-Freedom (SDOF) systems. On the basis of the SDOF systems, the overall structural damage index is obtained by a nonlinear time–history analysis for two reinforced concrete moment frame systems. It is clear that the developed compound IM shows significantly high-level correlation with structural response. The better the correlations, the more one can measure the earthquake damage potential. A single IM alone inadequately characterizes structural damage, highlighting the necessity of multiple IMs to estimate the possibility of structural damage. Full article