The stability of axially loaded steel columns with compact rectangular hollow sections at elevated temperatures is studied in this paper. The current Eurocode model for checking the buckling resistance of columns in fire was developed on a similar basis to that for ambient conditions. Due to the effect of the complex non-linear behaviour of steel in fire, the standard design model is not always fully appropriate, and certain parameter ranges may give unsafe results. In this work, an analytical method to determine the buckling resistance of steel columns at elevated temperatures is proposed, accounting for variable non-linear stiffness properties which have significant effects on the flexural buckling resistance of steel columns in fire. A finite element model was developed, and an extensive numerical study was performed to explore the effects of different parameters on the behaviours of steel columns at elevated temperatures. The proposed method is validated by comparing the performance with the results of the numerical model. Its improved accuracy with respect to the current Eurocode method is verified. The advantage of the new technique is its computational efficiency, which is valuable in reliability evaluations or data-based design procedures demanding numerous calculation cycles. The potential of the method for probability-based analysis is supported by the format, which enables us to explicitly handle the uncertainties of essential parameters. The proposed framework is suitable for extension to incorporate different material models and section types. Full article

The purpose of this study is to evaluate the multi-functional use of the domestic sleep environment (bedroom) and present evidence on outcomes that can be identified. By looking at the sleep environment in a broader context and considering the use of the bedroom space besides sleeping, this research responds to an information gap in sleep studies. A survey with multiple-choice questionnaire items was conducted with 304 participants in Australia to investigate the relationship between occupants’ use of the bedroom space and their sleep habits. We found evidence that today’s bedrooms are used for more than just sleeping, reflecting the respondents’ multi-functional needs. Of the respondents, 60% agreed to have a consistent sleeping routine, while 49% answered they have/might have a sleep problem. The mean hours spent in a sleeping environment are 9.31, while the sleeping mean hours are 7.12. While 40% reported using the bedroom as their living space, 61% said they prefer to use it only for sleep. Age, occupation and the bedroom’s location affect bedroom use and preferences. This study provides an initial inquiry into developing design strategies and understanding on the intertwined relationship between sleep and its environment. Full article

Solar Decathlon is a multi-disciplinary international competition that integrates energy-saving design strategies to design, build and operate zero-energy solar houses. This study focused on the 15 entries in the third Solar Decathlon China. It summarized their energy-saving design strategies into strategies of architectural design, equipment management, energy acquisition and intelligent regulation, and extracted a total of 22 key design elements. Based on the scoring results of the competition, this study analyzed the application of different design strategies with qualitative analysis; through quantitative analysis, 22 design elements were associated with the score, and the impact of different strategies on the score was comprehensively analyzed. As revealed in the data, design concept, functional structure and application type of renewable energy are significantly correlated with and have a great impact on the score; in contrast, building area and thermal buffer space are not significantly correlated with the score. On the basis of data analysis, this study provides a quantitative decision basis for the energy-saving design strategy of zero-energy buildings, and establishes an empirical model for the design of zero-energy solar buildings in Zhangbei County, Zhangjiakou City. This paper is helpful for the design practice and application of subsequent studies on ZEBs. Full article

This study is devoted to the possibility of using advanced insulation materials, such as Vacuum Insulation Panels (VIP), in the insulation and reconstruction of buildings, in connection with the green elements that are installed on the facade in the case of the use of external thermal insulation composite systems (ETICS). The use of VIP as part of the insulation system will result in a significant reduction in the required thickness of the insulation layer. In turn, the reduced overall thickness of the system will allow for easier direct anchoring of the elements of the green facade through the insulating layer to the base of the structure. The research carried out proves that, by using VIP in the insulation system (with a VIP thickness of 30 mm in combination with 20 mm of extruded polystyrene XPS), the thermal insulation properties can be significantly improved and, thus, the thickness of the insulation system can be reduced to 1/3 of the thickness of conventional insulation (while achieving the same thermal resistance), thereby enabling the anchoring of green elements on the surface of such an insulation system. Full article

This work aims to reveal the recent research trends in the consolidation of stone-built heritage and discuss the advantages and drawbacks of the options and strategies followed by researchers over the last 10 years. Peer-reviewed articles were used to build a database and analyze the details of the stone samples (chemical nature, type of voids, and condition), treatment protocols (application methods and consolidation products), and testing methods to assess the strengthening results of the treatments. In addition, the reported increments in the mechanical properties were also examined to reveal the strengthening capabilities of recent consolidation treatments. The statistical treatment of the results allowed pinpointing the stone varieties that need more frequent consolidation actions (limestone, biocalcarenite, and sandstone) and the aspects that make them more difficult and riskier. Other tendencies were discussed, for example, the predominant use of sound samples over decayed samples (61% vs. 39%) or the predominant use of alkoxysilanes (~46%) over other families of consolidants (e.g., nanolime, ~21%). The current consolidation treatments were found to improve stone strength; however, the most problematic issue in state-of-the-art is the difficulty of identifying high-risk situations of over-consolidation or poor distribution in depth because of either the lack of testing or limitations of the various assessment techniques. Full article

Scholars have examined the relationship between destination accessibility and various pedestrian-friendly environments in neighborhoods. However, there have been few studies on whether micro-scale environmental features promote access to supermarkets. This study fills these gaps by examining the accessibility of supermarkets and the meso- and micro-scale environmental features. In particular, environmental features that pedestrians can experience at the eye-level were estimated using the Naver pedestrian direction API and semantic segmentation technique. Multivariate regression models were employed to determine whether neighborhoods with high supermarket accessibility ensure walkable environments for the elderly. Our findings have shown that the walkability differs according to different levels of supermarket accessibility. Neighborhoods with high supermarket accessibility had high density and high diversity, and they provided high-quality sidewalk pavement. Conversely, elderly residents in neighborhoods with low accessibility had to pass through more pedestrian crossing facilities and steep slopes to go to do their shopping. These results can provide insight to policymakers and planners about the uneven accessibility of supermarkets and help improve neighborhood walkability for the elderly. Full article

A steel damper column is an energy-dissipating member that is suitable for reinforced concrete (RC) buildings and multistory housing. To assess the seismic performance of buildings with steel damper columns, the peak displacement of the whole building and the energy dissipation demand of the dampers must be evaluated. This article proposes an energy-based prediction procedure for the peak and cumulative response of an RC frame building with steel damper columns. The proposed procedure considers two energy-related seismic intensity parameters, namely the maximum momentary input energy and the total input energy. The peak displacement is predicted considering the energy balance during a half cycle of the structural response, using the maximum momentary input energy. The energy dissipation demand of the dampers is then predicted considering the energy balance during a whole response cycle using the total input energy. The local responses (e.g., peak drift, maximum plastic rotation of beams, maximum shear strain, and energy dissipation demand of dampers) are predicted using pushover analysis. Numerical analysis results for 8- and 16-story RC buildings show that the proposed prediction method achieves satisfactory accuracy. Full article

Elderly nursing homes in South Korea are vulnerable to evacuation in emergency situations such as fires. There are many elderly residents with reduced self-walking ability, so if a disaster such as a fire occurs, it is very likely to lead to a large number of human injuries. In elderly nursing homes, it is impossible for many elderly people to evacuate voluntarily without the help of staff. Therefore, it is very important to guide the behavior of staff when evacuating. The purpose of this study is to evaluate the effect of evacuation behavior of staff on evacuation time in a fire emergency in an elderly nursing home by adopting an agent-based simulation approach. The effect of staff evacuation behavior on the evacuation time was investigated based on the results of a new agent-based evacuation simulation model. In the simulation model, there are conditions for caregivers to designate and evacuate the elderly, as well as to set the evacuation priority for the elderly. The results of this study show that having the elderly occupants designated by the staff according to their zones and evacuating them together was the most important in reducing the evacuation time. This study contributes to a new agent-based evacuation simulation model by confirming whether the evacuation behavior of employees affects the evacuation time. Full article

The overall temperature in high latitude regions has been rapidly increasing in recent years, creating a demand for infrastructure to support increasing human activities. Recent advances in material science have resulted in the development of advanced high-strength steels (AHSS), which are new grades of cold-formed steel (CFS) with unprecedented strength. To design safe infrastructure, the material properties of AHSS under subzero temperatures must be quantified. An experimental investigation following the steady-state test protocol was carried out to quantify the subzero temperature effects on the material properties of AHSS and conventional CFS sheets with yield strengths ranging from 395 MPa to 1200 MPa. Two types of AHSS (dual phase and martensitic) and two types of conventional CFS (mild and high-strength low-alloy) were investigated at temperatures down to −60 ${}^{\circ }$C. The stress–strain relationship, elastic modulus, and key stresses and strains were reported from the experiments. The results show that AHSS’s material properties do not degrade but are mildly strengthened at subzero temperatures than at ambient, which indicates that AHSS is a suitable construction material for structural members in high-latitude regions. Furthermore, modeling on stress–strain relationships of AHSS and conventional CFS at subzero temperatures was developed, demonstrating excellent fits with the experiment data. Full article

Structural stress and deformation monitoring and analysis were carried out for the 54 m long-span steel roof truss. To ensure the safety of the construction process, the stress and deformation of the steel roof trusses were monitored throughout the construction process. The numerical modeling of the structures with six different working conditions was carried out, and the points with the most critical values of stress and deformation were found. This work provides a theoretical basis for field monitoring during and after construction. The results show that the maximum vertical displacement of a steel roof truss during all modeled working conditions and the maximum measured displacement are within the Chinese building code’s requirements. The maximum value of stress found during analysis of the structure during the construction process and the maximum measured stress are much less than the yield stress. The structural stress remains in the elastic range. The reasons for the differences between the calculated and measured results were analyzed. Full article

The drive-by method has become a popular indirect approach for bridge damage inspection (BDI) because of its simplicity in deployment by evaluating the bridge health status solely via the vehicle dynamic response. Derived from the vehicle dynamic response, the recent proposed contact-point response involves no vibration signal with the vehicle frequency, bearing great potential for drive-by BDI. However, an appropriate methodology for the application of contact-point response in drive-by BDI remains lacking. The present study proposes a novel drive-by method, in which a new damage factor index, i.e., the characteristic wavelet coefficient (CWC), is established for bridge damage identification in an efficient and accurate manner. The CWC is obtained by analyzing the contact-point response via the continuous wavelet transform (CWT) and complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) techniques. CEEMDAN is introduced to overcome the issue of modal aliasing and pseudo-frequency. First, the general framework of the proposed drive-by BDI method is introduced. Then, a demonstration case study is carried out to examine the effectiveness of the proposed method. Subsequently, a parametric study is carried out to explore the effects of several parameters on the performance of BDI including the scale factor, vehicle speed, environmental noise, and boundary effect. The results indicate that the proposed drive-by BDI method can better eliminate the mode mixing and pseudo-frequency problems during the extraction of the CWC, compared with the traditional ensemble empirical mode decomposition method. The extracted CWC curve is smooth, convenient for damage inspection, and has strong anti-noise performance. After adding white noise with a signal-to-noise ratio of 20, a bridge girder with a damage severity of 20% can be identified successfully. In addition, the selection of the scale factor is critical for bridge damage inspection based on the extracted CWC. The effective scale factor of the CWC extracted using the proposed method has a wide range, which improves the inspection efficiency. Finally, a low vehicle speed is beneficial to alleviate the adverse effect of the boundary effect on the damage inspection of bridge girder ends. Full article

This article presents, for the first time, the study of diabases from various ophiolite complexes from Greece and Cyprus to identify their performance as concrete aggregates. Within this scope, in the first step, diabase samples from four selected ophiolite complexes of Greece (Veria-Naousa, Edessa and Guevgueli) and Cyprus (Troodos) were collected in order to estimate their suitability as concrete aggregates by means of their petrographic and physicochemical characteristics. In the next step, concrete specimens were prepared and their mechanical strength was measured in order to investigate their mechanical performance. Additionally, their petrographic characteristics in relation to the mechanical strength of the created concretes were investigated for the first time. Concrete specimens prepared by employing diabases from the Veria-Naousa and Guevgueli complexes as aggregates were reckoned as the most durable ones in contrast to those derived from the Edesssa complex and even more so than those from Cyprus, with the latter containing the most altered diabases (rodingitised). The overall conclusion of this research is that the engineering properties of the aggregates were dependent on their petrographic characteristics and hence they influenced the final mechanical behaviour of each produced concrete. Full article

Aeolian sand widely exists in the desert of western China. The reinforcement of aeolian sand is of considerable significance to the construction of transmission lines in the desert. In order to study the impact of different cement contents and moisture content on the performance of the cement-stabilized aeolian sand, 18 types of samples of aeolian sand with different water and cement contents were prepared. The confined and unconfined compression tests of the aeolian sand samples were conducted on the TSZ series automatic triaxial instrument. The microscopic observation methods and macroscopic strength tests were adopted to understand the cement-stabilized mechanism. The results of the triaxial test manifest that both the moisture content and the cement content affect the stress-strain behavior of the cement-stabilized aeolian sand. The cement-stabilized effect on aeolian sand can be estimated by the degree of hydration reaction. Microscopic test results show that as the cement content increases, the pores in the microstructure decrease, and some crystalline substances appear. The content of calcium silicate hydrate (C-S-H), which is one of the hydration products, is measured by the X-ray diffraction method. The results indicate that the solidification effect of cement is related to the C-S-H percentage. For 3% water content, the percentage of C-S-H goes up first with the increase of cement content and then gradually decreases at the cement content of 6%. When the water content goes up to 5% and 7%, it is found that the production of C-S-H gel increases with cement content. Full article

The integration of Design for Manufacture and Assembly (DfMA) into the design process of industrialized construction has the potential to reduce errors and changes occurring after the design has been finalized, ultimately improving overall productivity. Based on DfMA, the designers would need to consider whether their designs meet the architectural and performance requirements, as well as the manufacturing and assembly requirements from assembly and manufacturing technicians. However, some limitations present challenges for DfMA-oriented prefabricated design, such as lack of information interoperability, lack of conflict detection and management, and inefficient data processing and requirement checking. Thus, this research presents a novel BIM and ontology-based framework for DfMA of prefabricated and modular components. Various types of algorithms, plugins, and programming are also integrated to support the operation of the framework. The primary functions of this framework include: (1) collection of various stakeholder requirements in a standardized data format; (2) conflict detection and resolution between the design, manufacturing, and assembly requirements; and (3) automated compliance checking of whether the designed BIM models meet DfMA requirements. This research applies the framework on a prefabricated hotel project as a case study to validate the feasibility of the framework. Based on the results of a user experience survey, the developed framework shows promise for improving the DfMA process and stakeholder communication. Although a few limitations were encountered, such as the low computer operating speed and the limited ontology, the framework has been validated and shows great potential in advancing prefabricated component design applications Full article

Design verifications of buildings are usually carried out supported by a finite element analysis (FEA), for which, however, there are only a few and almost exclusively non-binding application rules. Within the Cluster of Excellence Integrative Computational Design and Construction for Architecture (IntCDC) at the University of Stuttgart, Guidelines for a Finite Element-Based Design of Timber Structures have been developed. The scope of the guidelines is daily engineering practice, expert engineering applications and product development and certification. Essential parts of the guidelines are design procedures, modelling (including geometrical, material and imperfection modelling), analysis, model verification and validation and design. The content and application of the guidelines are described and illustrated in this paper using two benchmarks. These two benchmarks, which are based on experimental investigations, deal with the elastic material modelling of glulam made of beech laminated veneer lumber (beech LVL) and dowel-type connections for beech LVL members. The experimental basis of the benchmarks is described. With the experiments for the benchmarks, all Poisson’s ratios and the complete elastic material stiffness matrix of beech LVL are determined by means of an optical measuring system. The experimentally determined stiffnesses of the investigated dowel-type connections in beech LVL are compared with normative values. Based on the experiments, a numerical model is developed in RFEM (Dlubal). Full article