Conventional base isolators present two main issues: 1) a high cost of production, and 2) the presence of a certain amount of horizontal lateral stiffness. To address these issues, this paper introduces two novel base isolators called Scrap Tire Rubber Pad with Steel Rods (STRP-SR) isolator and Magnetic Levitated (Maglev) isolator. To reduce the production cost, the STRP-SR isolator consisting of bonded piled up scrap tire pads accompanied by four steel rods is introduced, which could be used in light buildings with a low ranking of importance. To provide an ideal bearing with zero horizontal lateral stiffness, the Maglev isolator is introduced, in which the building is levitated with a zero- carbon footprint using magnetic levitation technology. In this paper, the STRP-SR bearing was examined numerically under compressive and cyclic shear loadings and the efficiency of the STRP-SR bearing was investigated for an isolated two-storey building model using ABAQUS software. Moreover, the Maglev bearing was studied numerically using COMSOL software and its experimental specimen was tested on a shaking table. Based on the obtained numerical results, it was concluded that STRP-SR and Maglev bearings can reduce the absolute acceleration and displacement values by average percentages of 53.24 and 100, respectively, which highlights their capability in keeping isolated buildings safe. The experimental results for the Maglev isolator showed that the aforementioned reduction percentage was reduced to an average value of 74.67%, which still is an acceptable value for the efficiency of a practical bearing.

This paper presents a brief introduction on and comparative structural performance of two novel steel beam–column connections. One of them is a novel self-centering beam–column connection with circular friction pads, which eliminates residual drifts and has simple constructional details. In this regard, two full-scale experimental specimens of self-centering pinned connections with friction damper (SC-PC-FD) of two types were tested, one having two post-tensioned strands and the other having four. Moreover, using parametric analysis, the optimal characteristics of this connection were achieved, and its cyclic performance was compared to some existing steel beam–column connections. To enhance the seismic performance of moment beam–column connections without any reduction in their stiffness and removing the inelasticity far from the column face, a heat-treated hollow structural beam section (HBS) was introduced and was examined experimentally. For this purpose, the desired region of the HSS beam was heat-treated using a fabricated resistance furnace. Then, the cyclic performance of the HBS specimen was compared to an experimental specimen with the same properties, except the weakening approach of the HSS beam, in which the reduced beam section (RBS) was considered. The results showed that the four-strand SC-PC-FD connection was superior to the two-strand specimen, and SC-PC-FD connections exhibited a ductile and stable flag-shaped hysteretic behavior up to the interstory drift ratio of 7%. Regarding the observations obtained in the experimental study on HBS and RBS connections, it was concluded that the HBS connection could tolerate the applied cyclic loadings up to the interstory drift ratio of 6% without any occurrence of lateral–torsional buckling, which happened in the RBS specimen. Through a comparison of the SC-PC-FD and HBS connections, it was seen that SC-PC-FD connection can eliminate the residual drifts and provide higher ductility while keeping the main members in the elastic range.

Literature is not abundant in terms of the mechanical characterization of cylindrical shells for civil engineering applications, especially in terms of impact response. Therefore, this study intends to analyze the impact response of cylindrical sandwich shells incorporating different types of fibers. Three different configurations were considered (6C, 2C+2B+2C, and 2C+2G+2C), where the “number” represents the number of layers used and C= Carbon fibers, B = Basalt fibers, and G = Glass fibers. All configurations were tested for their static and impact strength. It was concluded that the constituents of the cylindrical sandwich shells are determinants in both static and impact strength. In terms of static performance, cylindrical shells produced only with carbon fibers are responsible for the highest compressive strength (873 N) and stiffness (354 N/mm), while the displacement is the lowest (4.4 mm). However, the incorporation of basalt fibers decreased these properties to the lowest values, and reductions of 22% and 44% were found for the compressive strength and stiffness, respectively, while the displacement increased around 66%. On the other hand, in terms of impact, significant benefits were achieved with the introduction of glass fibers. For example, the elastic recuperation was 25% and 64.6% higher than that obtained for the 6C and 2C+2B+2C configurations, respectively.

Mixed building frames constructed by reinforced concrete (r/c) in lower stories and structural steel in upper stories have been met with great scientifical interest as a common and often constructed building type. However, current seismic regulations do not provide special guidelines for the aforementioned vertically mixed building type, but only for building frames constructed with the same material throughout. In addition, a small number of respective literature works can be found, thus underlying the need for a thorough examination of the nonlinear behavior of mixed reinforced concrete—steel frames exposed to strong earthquakes. Mixed r/c-steel 3D frames were subject to non-linear time history analysis under selected strong earthquakes, considering appropriate nonlinear mechanical models for structural elements. Nonlinear response results were compared for two considered connection types of the steel part on the r/c part, which are called here as “fixed” and “fixed-pinned” connections. In this way, the nonlinear response of mixed frames is studied under extreme ground motions, towards the utmost unfavorable conditions. Selected comparative nonlinear response results and plots are presented to estimate the behavior of mixed frames. Qualitative remarks arise from the current described investigation leading to practical remarks for improving the design of mixed buildings that are available for the upgrade of current codes.

Analyzing and reinforcing concrete members (such as beams, columns, and shear walls) are fundamental to civil and structural engineering. Classical design methods based on hand calculations or interaction diagrams are available for various reinforced concrete sections. The goal of this study is to develop a new alternative design method of reinforced concrete shear walls using mathematical programming and numerical optimization. The design of reinforced concrete shear walls is based on the latest American Concrete Institute ACI 318-19 Code. The design method relies on an optimization formulation to determine the minimum required steel area subject to given factored loads (such as a combined bending moment and axial force on a concrete section). This study intends to present the design of concrete shear wall sections in a rigorously derived framework using different formulations. To make it more practical for civil and structural engineers to use, a widely available numerical solver in a Microsoft Excel spreadsheet is adopted as the optimization engine. Concrete shear wall examples are analyzed and designed using the proposed method, and the results are compared with those obtained using classical design methods. The new method using numerical optimization works well and is easy to implement in an Excel spreadsheet. The proposed design method provides a useful alternative for practical engineering applications.

The Han family compound is located in Shangli ancient town in the Sichuan province and is a well-preserved building complex of the Qing Dynasty in the ancient town. In 2005, in order to develop tourism, the government began using part of the courtyard as a museum; however, due to financial and human resources, the museum was closed, and the Han family compound fell into a dilapidated condition. In this paper, through a field survey, we found that the Han family compound has three compounds, the third of which has been abandoned, while the second compound has been developed by the Han family's descendants as a bed and breakfast, and the first compound has been left unattended by the government due to the right to use it. Through interviews with local visitor centers, village committees, and original Han family compound occupiers, we learned that the Han family compound is facing a difficult maintenance situation due to a lack of attention, unclear boundaries of authority and responsibility, a lack of available technical and financial support, and lack of professional restoration personnel. Therefore, we have to consider the problem of ancient building maintenance and protection. This paper briefly analyzes the current conservation concept of ancient building maintenance, and draws on excellent cases of ancient building maintenance at home and abroad to summarize the corresponding strategies to enhance the ideology of residents' maintenance and protection, use the conservation strategies of IPOGEA and ITKI, and give modern functions to ancient buildings in order to achieve the goals of building maintenance and protection and the sustainable development of the Han family compound. The aim of this study is to provide some reference for the conservation and development of similar architectural heritage.

This paper introduces a probabilistic assessment of steel column damage caused by blast loads, utilizing simulation reliability methods and gene expression programming. The research focuses on an H-section steel column and incorporates uncertainties associated with input loads (axial and blast loads) and geometric factors (i.e., maximum slenderness) under various boundary conditions (pinned and fixed supports). The reliability analysis employs three different methods: the point estimate method (PEM), Monte Carlo simulation method (MCS), and Monte Carlo simulation method with Latin Hypercube sampling (MCS-LHS). To establish the reliability analysis, formulas derived from a previous study conducted by the authors using gene expression programming are employed. Damage assessment is determined based on a damage index criterion, considering the post-blast residual axial load-bearing capacity of the steel column. The research presents the results in terms of damage probability, considering the different reliability analysis methods and boundary conditions. The findings demonstrate that the point estimate method effectively estimates the probabilistic response of the steel column with acceptable accuracy and less effort compared to the MCS and MCS-LHS methods. Furthermore, the MCS-LHS method demonstrates higher accuracy in estimating the probability distribution function utilizing the Latin Hypercube sampling method as compared to the MCS method. These findings emphasize the importance of considering uncertainties in calculating the column response under extreme dynamic blast loading.

Plastic production has grown faster than any other material in recent decades. As a consequence, a large amount of plastic waste is accumulating, which has a great impact on terrestrial and marine ecosystems. The aims of this research are to study the water resistance properties of new eco-friendly gypsum composites made with Low-Density Polyethylene (LDPE) waste additions in granular form. Three percentages of LDPE additions by weight have been used as partial replacement of the original gypsum material: 2.5%, 5.0% and 7.5%; the diameters of the LDPE aggregates were between 1 and 2 mm. The results show that the addition of these recycled raw materials reduces the total water absorption of the gypsum composites. On the other hand, durability tests have been carried out against the repeated action of wet chamber cycles and water–stove cycles. After carrying out these accelerated aging tests, it was concluded that all the composites produced in this research exceeded the minimum flexural and compressive strengths recommended by the EN 13279-2 standard. In view of the above, the gypsum composite materials produced are a sustainable alternative for recovering and revaluing plastic waste. In this way, granular LDPE waste shows its feasibility to be incorporated as a secondary raw material in the development of new precast construction products made under circular economy criteria.

The primary objective of this research is to present a dependable approach for optimizing daylight and energy consumption in buildings for climate change adaptation. This study focuses on identifying the most influential input parameters affecting daylight and energy consumption in the future climate for urban housing in Malaysia. To achieve this, Radiance and OpenStudio software is employed to assess the daylight level and energy usage of the studied building, respectively. Subsequently, a robust artificial neural network (ANN) model is developed, trained, and tested to simulate daylight and energy consumption in the building. Furthermore, daylight and thermal energy multi-objective optimization is conducted using the Wallacei plugin, which utilizes an NSGA-II algorithm. The key findings indicate that the optimized solution can improve the useful daylight illuminance (UDI-%) level by 14.9% and the cooling energy use intensity (EUI-kWh/m²) can be reduced by 50%. Sensitivity analysis reveals that in the future climate, the glazing transmittance has the most significant impact on daylight performance, while room depth is the most significant for energy consumption. This study demonstrates that the trained ANN model proposed in this research can accurately predict daylight level and energy consumption in the building. The ANN model attained R² scores of 0.955 and 0.997, MAE scores of 1.64 and 3.26, and RMSE scores of 2.23 and 4.52 for UDI and cooling EUI, respectively. The significant difference between the Pareto front solutions produced via simulation-based optimization and ANN model optimization is evaluated using two-tailed Student’s t-tests. The results demonstrate that the P-value of the two models has no significant difference, indicating that the ANN model can produce a similar Pareto front solution to that achieved using the simulation-based optimization. In conclusion, this novel model has the potential to be applied to similar buildings and climates for effectively predicting and optimizing daylight and energy consumption in the future climate.

Twentieth-century architecture stands as an imperative realm of experimentation, within which the architecture of the Modern Movement emerged from 1900 to 1940 with shapes, features, and materials completely different from pre-industrial buildings, rejecting traditional construction practices, techniques, and materials. Its key design concepts include (i) the “Form Follows Function” principle, establishing a strict relationship between building aesthetics and function, favoring min-imalism, balanced composition, and visible materials; (ii) the creation of comfortable and healthy buildings, with natural light and ventilation through windows, biophilia, and spacious rooms; and (iii) advancements in engineering, facilitating novel design possibilities (e.g., metal-framed curtain walls, complex windows) and the manufacture of mass-produced materials (e.g., glass, steel, rein-forced concrete, plywood, Masonite, and cast iron). These criteria directly influence energy effi-ciency and human comfort. Nevertheless, technical problems have emerged due to inadequate com-prehension of the long-term performances of these experimentations, leading to deterioration and aging. This research provides a complete overview of the energy and climatic performances of Mod-ern Architecture, discussing building physics implications of the key design principles through sev-eral case studies.