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To develop functional honeycomb plates (HPs) with great thermal performance, This paper uses a heat flow meter to determine the equivalent thermal conductivity λ E of honeycomb plates (HPs) positioned horizontally under cold-above/hot-below conditions and combined with theoretical calculations, the influence mechanism of their geometric parameters on their heat transfer performance were investigated with different thicknesses h and cell wall lengths of 8 mm and 16 mm (HP8 and HP16, respectively). The results show that the thermal insulation performance of HPs with different cell side lengths varies with the plate thickness. HP8 presented a better thermal insulation performance when h = 40–60 mm. Based on this, the concepts of matching honeycomb structure and matching convection and the suggestions that according to the needs of a project, HP8 or HP16 can be reasonably selected, and the stacking of two kinds of plates can be optimized were first proposed. And it can be obtained that if the experimental λ E results of a HP are applied to a beetle elytron plate with the same thickness and honeycomb structure size, the heat insulation of the beetle elytron plate (BEP) would be superior to that of the HP. This paper lays a theoretical foundation for the research and development of multifunctional BEPs with heat insulation properties was verified. Finally, the internal influence mechanism of the difference in temperature distribution on the upper and lower surfaces and the three-dimensional size of the honeycomb cells on the matching honeycomb structure and matching convection.

Due to the growing concerns of deforestation, renewable materials as recycled cellulosic waste and non-wood fibres provide an alternative solution for partial replacement of wood resources as a reinforcement agent in building material. This study examined the effect of cellulose pulp inclusion on the physical, mechanical, and thermal performance of extruded cement stabilized earth-based matrices. Laboratory experiments of earth-based matrices reinforced with two types of fibres (bamboo pulp and recycled waste carton pulp) at varying fibre contents (0, 5, 7.5 and 10 %wt.) were performed. The results show that the inclusion of recycled waste carton pulp fibre in the soil matrix significantly improved the performance of the composites compared to matrices reinforced with bamboo pulp fibre. Addition of recycled waste carton pulp displayed improvement in flexural strength (56%), in toughness (733%), and in thermal insulation (36.35%) compared to the control sample. Inclusion of recycled waste carton pulp in earth-based matrix increases the moisture loss, the drying shrinkage and behaves as a water reservoir for earth-based materials. It has been concluded from this study that recycled waste carton pulp has the potential as a suitable reinforcement for the promotion of lightweight earthen wall block materials (reduction of bulk density up to 21% after the inclusion of 10% of recycled waste carton pulp), where flexural strength, ductility, and thermal insulation performance are the primary requirements. In addition, the successful replacement of virgin bamboo pulp fibres with recycled waste carton pulp fibres reduces the environmental footprint of the building material. Therefore, the use of this recycled waste carton pulp in the construction industry will be an attractive alternative as it will solve both energy and environmental concerns.

The increasing urban development, led by concrete, requires a higher availability of materials and energy, and it will be responsible for a high waste generation. To face the exploitation of natural resources, the use of fossil fuels and the reduction of waste disposal, new environmental-friendly strategies emerge accomplishing the circular economy principles. In this research, the use of poor reactive agro-industrial ashes as sand replacement in cement-based materials is investigated. Poor reactive sugar cane bagasse ashes (fly and bottom ash -SCB FA and SCB BA, respectively) from a power plant in Dominican Republic have been used in substitution rates of 10%, 20% and 30% of weight of sand. Physico-chemical characteristics of ashes are investigated and correlated to the performance of the bio-concretes. SCB FA showed being an enhancer of durability-related properties of the concrete even with high content of silica in form of quartz, due to the capability of modifying the microstructure of the concrete and an additional binding capacity of chlorides ions. Durability-related tests (open porosity test, electrical resistivity test, capillary absorption test and chloride migration test) have been conducted at 28, 60, 90 and 240days. Direct correlations exist when compared chloride migration resistance against porosity and electrical resistivity in concretes with SCB FA, not so for capillary absorption. This demonstrates the inadequacy of establishing conclusions about durability performance of bio-concretes based on durability tests when run independently. The use of agro-industrial ashes as substitutes of natural aggregates not only reduces the consumption of natural sand but can deliver bio-concretes with potential benefits in terms of compressive strength and durability.

This paper conducted several experimental tests and theoretical analyses to present a comprehensive study on the behavior of dry-connected steel plate frame-reinforced brick walls under axial compression. One unreinforced brick wall, two brick walls reinforced with dry-connected steel plate frame, and one brick wall reinforced with steel strips were fabricated for axial compression tests. The experiments generally showed that steel plate frames effectively improved the structure's bearing capacity and axial stiffness and impeded its cracking. Increasing the thickness of steel plates further improved the bearing capacity but undermined the ductility of the composite wall. Besides, based on the buckling theory of steel plate and the existing calculation theory of masonry strength, this paper also proposed formulas for determining the bearing capacity of the composite wall. The calculations of formulas exhibited acceptable accuracy in comparison with the experimental results.

Modularisation of efficient and cost-effective volumetric modules is a complicated procedure that involves adept material knowledge, advanced structural analyses skills and sound manufacturing awareness for professionals involved in it. This paper presents the design and structural modelling of an efficient and highly optimized module having an ultrathin mild steel base. First, the structural analysis, and then the testing of the manufactured ultrathin base of the module was performed. Then, the structural analyses for the deflections of the entire prefabricated module using computer-aided Extended Three-Dimensional Analysis for Building System (ETABS) were carried out. The modal analysis for the module was also performed to observe and develop connection strategies against the lateral deformations. Angle brackets connections were proposed at the corner of the adjacent walls in their top, middle and bottom to control lateral deformations that can induce damages to the non-structural elements. Moreover, a lifting system for the safe transport of the module was designed. Furthermore, the analysis revealed that the serviceability of the module onsite was enhanced by providing packers support at the critical locations of the base of the module. The findings of this paper are significant and provide the framework with full guidance for optimised, cost-effective and safe design, and installation of the volumetric modules for modular building projects.

The corrosion of reinforcement materials induced by chloride attacks is the primary reason for the deterioration of the seismic performance of reinforced concrete (RC) structures. In this paper, 12 RC beams with different corrosion levels, shear span to depth ratios and stirrup ratios were subjected to accelerated corrosion tests in an artificial climate as well as quasistatic cyclic loading tests, and the corrosion form, failure process, bearing capacity, deformation capacity, energy dissipation capacity, stiffness and strength degradation of corroded RC beams were investigated. The results showed that the artificial climate corrosion method could simulate the uneven corrosion form of steel bars in a natural environment; the corrosion of steel bars would intensify the shear failure characteristics of specimens; the degradation rates of the bearing capacity and deformation capacity of corroded RC beams with different shear span to depth ratios and stirrup ratios are significantly different; and the degradation degree of bearing capacity of specimens with a high shear span to depth ratio is 3.58 times higher than that of specimens with a low shear span to depth ratio. Subsequently, a numerical modeling method for corroded RC beams based on SFI-MVLEM was proposed, empirical formulas for the stiffness coefficient of the corroded dowel were determined based on experimental data, and the bond-slip deformation was simulated by the infinitesimal algorithm and zero-length fiber section element. The proposed model was accepted to numerically simulate 12 corroded RC beams in this paper, and the average values of the bearing capacity error and energy consumption error of the simulation results were 10.07% and 13.09%, respectively, indicating that the proposed model had good accuracy and could be adopted to predict the residual seismic performance of corroded RC beams.

This paper presents experimental investigation on evaluation of performance of a new type of steel reduced beam section (RBS), designated as V-cut, and on its role in improving overall safety of RBS-CFT connections subjected to cyclic load. Detailed design steps adopted for design of the V-cut RBS with lower depth of cut, as compared to that in the conventional radius cut RBS, are reported in this paper. Behavior of two types of steel RBS and concrete filled tube (CFT) connections with bidirectional bolts were examined. An experimental study was performed to compare the performance of V-cut RBS with that of the conventional radius cut RBS under cyclic loading. It exhibited improved hysteretic behavior, and the new RBS-CFT connection is found to be semi-rigid in nature. Test results show that the energy dissipation in the composite steel connections with V-cut RBS is higher than that with radius cut RBS. The application of V-cut steel flange beam effectively enhanced ductility and reduced the residual torsional deformation. It reached a rotational capacity of 0.04 radians without any damage in the joint panel region, and thereby meets the seismic provisions of the AISC as a special composite moment-resisting frame. Further, a simplified numerical simulation of force-deformation hysteretic behavior of RBS-CFT connections was carried out using OpenSees software. Simulated force-deformation hysteresis loops are found to be in close agreement with those obtained from experimental investigation.

Bamboo can be easily cultivated and harvested in a relatively short time and has been widely known as a sustainable building material. The study on the long-term creep behavior of full-culm bamboo members is of great significance for the design and use of bamboo structures in engineering, but there are few studies. This paper presents an experimental and numerical study on the creep behavior of full-culm original bamboo beams. In this study, two groups of bamboo beams with different stress levels were analyzed, and the fitting results based on Burger model were obtained. Short-term material properties test was firstly carried out to determine the ultimate strength of Phyllostachys edulis (or Moso bamboo). Secondly, in the creep test, 15 full-culm original bamboo beams were subjected to different constant stress levels for 180 days in an indoor environment, and the creep behavior of bamboo beams was observed and measured over time. Then a creep model of numerical analysis procedure based on the Burger model was established to simulate the creep behavior of each beam. By comparing the numerical analysis results with the test results, basic creep behavior characteristics including creep rate and proportion of each deformation (instantaneous elastic deformation, viscoelastic deformation and viscous deformation) were analyzed and discussed in depth. Finally, the creep behavior of full-culm original bamboo beams was evaluated by the acceptance criteria used for wood and wood-based products. The results indicated that the developed Burger model can well capture the trend of creep behavior including low and high stress level, and the full-culm original bamboo beam under lower stress level has the potential to replace timber in terms of withstanding long-term load. The creep test and numerical analysis of the full-culm original bamboo beams in this paper can provide a reference for follow-up study.

This paper investigates several in-service and alternative designs for corbel connections in partially composite load-bearing concrete sandwich wall panels. Current practice commonly uses one of two options: 1) creating a solid concrete section at the corbel location, or 2) creating an internal pilaster within the panel at the corbel location, which is done by local thickening of the wythe which results in a reduction in insulation thickness. Reducing insulation thickness reduces the thermal efficiency of the insulated wall panels at the corbel locations and can make fabrication difficult. This study involved testing twelve sandwich wall panel corbel specimens to quantify the strength of several designs and validate them through a modified strut-and-tie design method to enable future designs and the use of those presented. This paper illustrates nine successful alternative corbel-connections that reduce thermal bridging by using different materials to resist the tension tie force at the top of the corbel including GFRP U-bars, HK connectors , IconX GFRP and IconX CFRP connectors, and GFRP grating. Test results indicated that thermal bridging at the corbel connections can be reduced without large-area reduction of the insulation thickness. Additionally, results suggest that common, off-the-shelf sandwich wall panel connectors can be effectively used to transfer the tension tie force between the interior and exterior wythes.

Global energy use shows that cooling and heating are responsible for the highest energy use in buildings. The trend in building energy consumption has been steadily increasing and is expected to continue to rise significantly in the future. The application of reflective foil in the form of reflective insulation and radiant barrier as a roof thermal insulation system is a potential means of reducing cooling energy in buildings, especially in the tropics. It is proven effective in reducing the heat gain across the roof and can enhance indoor thermal comfort. This paper reviews the thermal performance of reflective insulation and radiant barrier as a roof insulation system. Moreover, this paper also discusses and analyses various types of thermal performance test methods such as laboratory equipment, indoor test rig, field measurement, computational fluid dynamics, and building performance simulation. This paper also discusses several factors such as emissivity value, air gap thickness, weather, and climatic conditions on the thermal performance. Dust accumulation and prevention methods will also be discussed.

The high proportion of energy consumed in buildings has engendered the manifestation of many environmental problems which deploy adverse impacts on the existence of mankind. The prediction of building energy use is essentially proclaimed to be a method for energy conservation and improved decision-making towards decreasing energy usage. Also, the construction of energy efficient buildings will aid the reduction of total energy consumed in newly constructed buildings. Machine Learning (ML) method is recognised as the best suited approach for producing desired outcomes in prediction task. Hence, in several studies, ML has been applied in the field of energy consumption of operational building. However, there are not many studies investigating the suitability of ML methods for forecasting the potential building energy consumption at the early design phase to reduce the construction of more energy inefficient buildings. To address this gap, this paper presents the utilization of several machine learning techniques namely Artificial Neural Network (ANN), Gradient Boosting (GB), Deep Neural Network (DNN), Random Forest (RF), Stacking, K Nearest Neighbour (KNN), Support Vector Machine (SVM), Decision tree (DT) and Linear Regression (LR) for predicting annual building energy consumption using a large dataset of residential buildings. This study also examines the effect of the building clusters on the model performance. The novelty of this paper is to develop a model that enables designers input key features of a building design and forecast the annual average energy consumption at the early stages of development. This result reveals DNN as the most efficient predictive model for energy use at the early design phase and this presents a motivation for building designers to utilize it before construction to make informed decision, manage and optimize design.

Based on the field measurements on a 600-m-tall skyscraper equiped with an active tuned mass damper (ATMD) system, this paper investigates the control performance of the world's largest ATMD system to suppress the building vibrations. On-site forced vibration tests on the skyscraper were first conducted and the results showed that the ATMD system can increase the damping ratios of the fundamental sway modes up to about 11 times. Accordingly, ambient vibration tests on the building during Super Typhoon Hato were carried out, and the measured building acceleration responses showed that the ATMD system can effectively suppress the wind-induced vibrations of the skyscraper. Moreover, the structural damping ratios of the building with and without the operation of the ATMD system were identified, which showed that the ATMD system can significantly boost the damping ratios of the fundamental sway modes of the building for suppressing wind-induced vibrations, while it had limited effects on higher modal responses. The paper aims to provide useful information for the design of active vibration control systems and the wind-resistant design of high-rise buildings.

This paper presents investigations into the overall stability design of irregularly-shaped concrete-filled steel tubular columns with T-shape (T-ICFSTCs). The T-ICFSTC consists of I-steel, U-steel, and infilled concrete, forming a multi-cell steel tubular column. They are applied in the T-shaped sectional corner of the intersection between two walls in the residential buildings structures. The overall instability of the slender T-ICFSTCs may still be a significant concern in their strength design when they are placed in a higher spacing between two adjacent floors. This paper mainly focuses on establishing a design method for predicting the overall stability capacity of T-ICFSTCs subjected to axial load. Firstly, experimental investigations of an end-hinged T-ICFSTC and an end-fixed T-ICFSTC under axial load were carried out for checking its overall stability bearing capacity. Subsequently, the refined finite element (FE) model of the T-ICFSTCs is established and validated by the experimental results. In addition, the elastic buckling behavior of T-ICFSTC is studied by employing finite element (FE) eigenvalue buckling analysis, and the corresponding normalized slenderness ratio is obtained in the form of the Euler formula. Finally, based on the FE model validated experimentally, the parametric analyses of T-ICFSTCs are performed to investigate their overall stability capacities through changing the effects of steel ratio, sectional size, and material strength combination between concrete and steel. With these FE parametric analytic results, the overall stability coefficient φ, as well as φ-λ curves of T-ICFSTCs, are then obtained. These curves form the overall stability design formula of T-ICFSTCs loaded axially and apply in a common range of the percentage of load-carrying capacity shared by concrete. This design formula provides fundamentals to further develop a comprehensive design method of the T-ICFSTCs subjected to combined axial loads and moments.

The Polish energy market heavily relies on coal. Pressured by the European Union, the Polish government has recently decided to accelerate coal phase-out and to gradually shut down all coal mines by 2049. In that context, it is necessary to assess the Polish energy market's state regarding energy efficiency, especially in the building stock. This paper aims to provide an overview of the current state of energy efficiency of residential buildings in Poland and insights into its future trends. A literature review was conducted, accompanied by focus group discussions with Polish building energy efficiency experts. The Polish energy sector is under a remarkable transformation that may be going too fast. A large gap between expectations, practices, and requirements can be observed. Raising awareness and capacity building in the energy efficiency sector, and a set of accessible guidelines should be developed so that the transformation is implemented correctly. A SWOT analysis results define the key opportunities and threats that are critical to meet net-zero emissions goals. The paper provides findings and insights on the 2020 targets status quo and raises awareness among stakeholders and fills a knowledge gap regarding energy efficiency in the Polish residential building stock.

This paper experimentally explored the influence of cracks on cyclic behavior of moment-resisting bolted glulam joints, and investigated the strengthening of self-tapping screws and friction dampers. Under reversed cyclic loading, the failure modes and hysteresis curves of pre-cracked specimens have been presented and analyzed in this paper. It was found that initial cracks not only led to the decrease in the moment capacity and elastic stiffness , but also impaired the ductility behavior and energy dissipated capacity of bolted glulam joints. The ductility ratio and accumulated energy dissipation can be reduced by 30% and 60%, respectively. With the installation of self-tapping screws and friction dampers, significant enhancement was observed in the above mentioned mechanical parameters of pre-cracked bolted joints . The elastic stiffness and energy dissipation are improved by 144% and 613%, respectively. Further, an analytical model is applied to calculate moment capacity of strengthened bolted joints and validated by experimental results.

The present paper describes a numerical model that has been developed in order to analyse the long-term behaviour of beams built in different stages under serviceability loads, considering the effect of delayed deformations due to creep and shrinkage. The rheological model for concrete creep is based on a modified version of the solidification theory while the cross section behaviour is described by means of a fibre model. The paper discusses the performances of the model in simulating the behaviour of two fullscale beams tested by the authors.

Silica aerogel is a nano-porous material with remarkable insulation properties . Because of this, it can be an ideal alternative to traditional thermal insulating building materials which can promote energy efficiency in buildings. Consequently, it is gaining more interest in the construction industry and now many researchers have carried out investigations on incorporating silica aerogel in cement composite . Currently, most of these studies focused on the thermal conductivity and compressive strength of the cement composite. Therefore, this paper reviews the prior development and current findings of silica aerogel incorporated cement composite in promoting such an energy efficient building material. The effect of different forms of silica aerogel on the physical and mechanical properties of cement composite is discussed. In general, silica aerogel incorporation in any form (cement/sand replacement or as additive) tends to improve the thermal insulation (up to 0.02 W/m.K) of cement composite, whereas the density and mechanical strengths tend to reduce substantially (up to 90%). Furthermore, with the incorporation of silica aerogel, the porosity and water absorption of cement composite increased up to 3 times. Finally, this paper also describes the limitation of silica aerogel incorporation in cement composite. In addition, it highlights the future studies required to promote the adoption of such sustainable energy efficient buildings material on a larger scale.

This paper presents an experimental, analytical and numerical comparison of the behavior of lightweight and normal weight concrete beams strengthened with externally bonded high modulus carbon fiber. The main objective of this paper is to study the efficiency of using CFRP with all-lightweight concrete beams in flexural performance and validate the use of the modification factor (λ), proposed by ACI 318-19 for various concrete parameters, in adjusting the ACI 440.2 debonding strain . An experimental program was conducted using six full-scale T-beams made of two different concrete types, normal weight concrete, and all-lightweight concrete. Each series consisted of a control beam, and two beams strengthened using either two or four layers of high modulus CFRP. The results showed that the percent increase in flexural capacity is more evident in the normal weight beams as the number of layers increases. At the same time, this increase in lightweight beams is shown to be about the same beyond the use of two layers. Moreover, the reduction factors were found to be 0.93 and 0.85 leading to accurate recovery of the debonding experimental failure using the ACI 440.2 equation for the two-layered and four-layered beams, respectively. A nonlinear analysis parametric study was conducted to examine the parameter not varied in the experiments. A comparison to the debonding strain specified by other standards and models was also performed.

This paper totally reports the results of 8 pure torsion tests on channel steel reinforced concrete beams (CSRCB) and one pure torsion test on normal reinforced concrete contrast beam. The variables studied were the concrete strength, the configuration form of stirrup, and the form, angle, spacing of lace bar. It is shown that the concrete strength, stirrup disposition and channel steel have significant effects on the torsional capacity of the beam after comparative analysis. The failure mode and crack patterns of test specimen are investigated, also the working mechanism of channel steel and the concrete are analyzed in this paper. Finally, a calculation formula for cracking torque and ultimate torque of CSRCB are proposed. Good agreement was demonstrated between the test results and the calculation results which indicates that the calculation formulas proposed in this paper are applicable to the calculation of cracking torque and ultimate torque of CSRCB.

In this paper, three translations and three rotations of the unmanned aerial vehicle (UAV) were derived through the suggested Normalized Cross Correlation (NCC) based template matching computer vision method and their effect on the monitored structural displacement is analyzed. The NCC-based template matching is used to obtain the vibration of UAVs by tracing far-field background points at the recorded images. The images captured at any general orientations are rotated back to their original positions which could detect errors in the monitored displacement induced by the rotation angles. A fast NCC-based template matching method was also proposed in this paper, which could accelerate the original NCC-based template matching method significantly and reaches the same level accuracy as that of the original NCC-based template matching method. In order to verify the concept, a series of experiments were performed on a Multipurpose Testing System (MTS) machine with amplitudes of 10 mm, 5 mm, and 2.5 mm and frequencies of 2 Hz, 1 Hz and 0.5 Hz, respectively, at the same time a UAV and a fixed camera were used to record the motions of the MTS piston. The derived displacements through the UAV and the fixed camera are compared with the true motions of the MTS machine. Excellent precision and consistence were obtained for the UAV monitored displacement, the MTS piston motion, and the fixed camera derived displacement. Comparing to the case of the fixed camera, scales and rotation angles of the UAV are critical and largely affect the accuracy of monitored displacements. A field experiment was conducted to test the proposed method in a windy environment. Excellent agreement was found between the monitored displacement obtained by the UAV and that derived from the fixed camera.

Traditional light timber framing systems, comprised of stud to top and bottom plate connections, suffer from relatively low stiffness along compression perpendicular-to-grain of the plates, leading to excessive shortening of studs in mid-rise buildings. Experimental testing of timber stud to plate connections revealed that a reinforcement technique employing self-tapping screws, placed at the top/bottom plate interface, was an efficient way to enhance the connection stiffness and alleviate permanent displacements. In other words, the combination of bonding stress development at the interface of self-tapping screws and timber stud as well as plastic deformation , built up in timber plate in compression perpendicular-to-grain, plays an important role in improving the bearing stiffness/strength of these connections. In this paper, structural performance of light timber framing connections, strengthened with self-tapping screws under gravity loading is investigated, utilising finite element modelling . Continuum damage mechanics framework along with traction-separation cohesive zone technique are incorporated in detecting various failure scenarios and damage propagation for timber components in the finite element modelling. Small-scale unreinforced and reinforced stud to top/bottom plate connections using the Machine Graded Pine timber and high strength self-tapping screws were employed and tested experimentally to calibrate the finite element modelling parameters. Calibrated parameters are then utilised to establish a full-scale light timber framing finite element model. It is demonstrated that finite element models established in this paper can predict the load-displacement response and failure modes of reinforced light timber framing systems.

To effectively improve the heat storage performance of concrete radiant floor, a kind of concrete radiant floor with finned water supple pipes (Finned Concrete Radiant Floor) was designed. In the present paper, the heat storage performance of the new type concrete radiant floor was discussed based on experiments and a new simplified model. Experimental results showed that the average heat storage rate of the Finned Concrete Radiant Floor for start-up stage was about 88.7 W/m2, 152.2 W/m2and 218.7 W/m2 under the condition of water supply temperature 25.0oC, 29.8oC and 34.6oC, which was about 2 times that of a non-Finned Concrete Radiant Floor. Calculation results showed that the average heat storage rate was relevant to both fin height and fin material, but irrelevant to fin thickness, and pipe spacing had a significant effect on the heat storage performance. This paper can provide a certain data basis for a better design of Finned Concrete Radiant Floor.

The paper presents and discusses the results of a numerical study on post-fire (residual) behavior of reinforced concrete (RC) beams with critical tension lap splices . It is based on the experimental findings and the validation of the numerical approach in the accompanying paper and further analyzes the residual performance by varying most influencing parameters such as bond length, fire duration and concrete cover to the spliced reinforcing steel. Three-dimensional numerical (FE) analysis is performed employing the temperature dependent microplane model for concrete in the framework of the smeared crack approach. The numerical results show that the exposure to fire can change the strength hierarchy of the flexural member such that the splice lengths required to develop the bar under ambient (unheated) conditions may not be sufficient to develop the bar in residual (post-fire) conditions due to the preceding bond splitting failure. It is further found that increased concrete cover does not significantly enhance the post-fire flexural capacity . In closing, a design concept for the determination of the required bond length in case of fire loads is presented.

In building energy conservation , HVAC systems have great potential, and load prediction plays an important role in optimizing system control and improving system energy efficiency. Therefore, improving the accuracy of load prediction is of great significance. This paper aims to improve the prediction accuracy of the data-driven model of load prediction through optimizing the input variable selection. Factors such as outdoor temperature, wind speed, solar radiation, indoor temperature and user behavior have different mechanisms of action to influence the heating load, and there exists difference among the influence degree of each factor on the heating load at each moment. Therefore, the optimal input variable used by the heating load prediction models at different moments will be different. Based on this, this paper proposes to establish an input variable selection method based on hourly correlation analysis. Taking an office building as the case building, this paper uses the back propagation neural network (BPNN) model and the support vector regression (SVR) model to compare the selection methods of hourly correlation analysis and non-hourly correlation analysis. The results show that the influence degree of solar radiation intensity and the historical load at the moment of 24 h ahead on the load at each moment have great difference. Compared with non-hourly correlation analysis, hourly correlation analysis can reduce the root mean square error (RMSE) of the prediction results of the BPNN model and the SVR model by an average of 10.4% and 12.9%, respectively, and increase the coefficient of determination ( R2) by an average of 11.7% and 7.9%, respectively, while all the calculation time is about 0.4 s. This shows that the heating load prediction method based on hourly correlation analysis can improve the prediction accuracy of model while keeping the prediction rate unchanged.

Urban densification represents one of the biggest universal challenges of contemporary cities: the increase of urban population requires new spaces to accommodate the growing demand for housing, working and tertiary activities. However, the land available for new constructions in highly urbanized areas is very limited. In this framework, the vertical extension of existing buildings is the most sustainable strategy and fascinating. Masonry structures , constituting a major part of the built stock in the historical city centres of several European countries, are particularly suitable for vertical addition of extra-floors, since they generally exhibit an adequate overstrength for bearing an increase of gravity loads, although seismic retrofit interventions are usually required. In this paper, starting from the case study of the historical town of Pozzuoli, in South Italy, an “antifragile” approach, based on the intermediate isolation system, is suggested to rise the height of the masonry building , while reducing the global seismic demand. For this aim, in this paper are analysed the architectural-functional and structural design issues related to a vast-scale application of vertical additions isolated on the top of existing structures. Further, the feasibility and effectiveness of the strategy are discussed, and benefits in terms of seismic performance are evaluated.

The air volume control performance has an important impact on Heating, Ventilation and Air Conditioning (HVAC) system energy efficiency, indoor air quality and thermal comfort. However, one of the challenges in researching the air volume control of HVAC systems is that the controlling capacity of air dampers is related to the resistance of the entire duct system . The working flow characteristic (WFC) curve of the air damper varies across different duct systems, which strongly affects the damper control performance. Therefore, for this problem, this paper employed the combined CFD numerical simulation and experimental verification to obtain a novel air damper and its controlling formula. The novel air damper has good controlling capacity, and its flow characteristic curve does not change with the difference of the duct system. This paper offers a reference for the hydraulic balance of ventilation and air-conditioning systems and provides a new perspective for precise air volume control.

This paper focuses on introducing two methodologies related to buckling-restrained braces (BRBs): one for determining the acceptance criteria generally used in performance-based seismic design (PBSD), and another for assessing a damage index (DI) when BRBs are subjected to seismic actions . Both methodologies are established from the results of experimental test conducted on a series of full-scale BRB specimens. In total 19 full-scale BRB specimens were manufactured with local industry and workforce. 14 BRB specimens were tested using a low-cycle loading protocol, and five more BRB specimens were tested using a high-cycle fatigue loading protocol. The specimens were designed having differential deformation and energy dissipation capacities. For the low-cycle protocol, the axial strain in the BRB core was continuously increased until failure, while for the fatigue protocol, the axial strain in the core was increased from zero to 1.5%, and continued at 1.5% strain until core failure occurred. This paper also describes the results of a series of nonlinear dynamic analyses carried out on a sample building in order to validate the proposed methodologies when subjecting the building to ground motions. The results provided sufficient arguments to conclude that: (1) the proposed acceptance criteria is capable of considering the effect of (i) core plastic length, (ii) cumulative plastic deformation , (iii) and brace failure type (depending on the loading history). (2) The proposed damage index is shown to be capable of considering the effect of the maximum core strain attained as well as the cumulative plastic deformation effect. Moreover, a qualification scale was assigned to the proposed damage index as a tool for evaluating whether the BRB element should be replaced or left on site. Finally, the results suggest that the proposed methodologies can be useful in structural design practice.

This paper reviews and extracts lessons from historic buildings, whose stability relies mainly on compression to resist gravity loads, that can inform the construction of affordable housing and shelters using 3D printed concrete without reinforcement and formwork. The first part consists of a literature survey of historic constructions with systems relying on compression considering four vectors of analysis: (1) form; (2) structural principle; (3) materials; and (4) construction process . The survey starts by identifying forms whose structural principle may be adequate for 3D printing of concrete applications. Then, historic structures displaying similar forms are analyzed in terms of structural behavior, the types of materials employed, and the construction process used to obtain foundations, walls, and roofs. A series of historically inspired shapes for printing is thus obtained from this survey. To address the printability of the structures identified after the survey, the second part of the paper provides a brief description of existing processes for construction scale printing considering material aspects, such as fresh state behavior, and printing system configurations. Addressing the fresh state properties of concrete is crucial as it determines whether the structure fails during printing. Finally, a set of strategies including potential toolpaths and intermediate states are defined to print the identified forms, considering issues concerning material requirements and printing process.

Several aspects hinder the application sustainability in construction industry. The most prominent problems are related to the conservation of natural resources and the generation of construction and demolition wastes. Previous studies indicated that these problems are due to lack of information available to construction projects stakeholders on the proper handling of building materials in their different lifecycle stages. This paper presents Material Passport (MP) tool that provides information on how to handle building materials at the construction stage and how to benefit from them at their end-of-life stage through different recovery opportunities. This tool provides three quantitative indicators that assess building's sustainability: 1) deconstructability score; 2) recovery score; and 3) environmental score. These indicators help stakeholders to choose more sustainable solutions to building elements in the initial stages of the project. The paper introduces a framework that incorporate MP within Building Information Modeling (BIM). Such incorporation automates sustainability assessment as well as facilitating the documentation and sharing of building's information for future needs. A case study of a traditional residential building is presented to illustrate the concept of the material passport. Also, new alternatives of modular building concept are presented to validate the sustainability indicators, allowing a comparison with traditional building to reach more sustainable solutions. The results reveal that modular buildings are preferred as expected, demonstrating the effectiveness of the presented tools in evaluating alternatives. The results also show the influence of the parameters used in calculating the presented indicators, such as the connection type and the material used. The research provides a methodology that solves the problem of the of insufficient information in order to achieve sustainability for buildings by including quantitative and qualitative information. The provided information covers all lifecycle stages of the building, making it more comprehensive compared to other tools.

Wooden hypostyle structures are primarily built using timber-framed construction types, surrounded by masonry walls on two or three facades . This construction technique is a combination of Asian (wooden frame) and Byzantine (masonry wall) techniques. The primary load-bearing system in these structures consists of multiple rows of wooden pillars. This paper focuses on the restoration of a historical wooden hypostyle mosque constructed in 1366. The mosque is a crucial example of wooden hypostyle tradition in the Anatolia region of Turkey. The study consists of four steps: field survey, lab tests, restoration practices, and seismic performance analyses for the examined structure. The on-site examination includes the visual inspection of material deterioration and the analyses of obtained samples from different places of the structure. Moreover, a building survey was carried out using three-dimensional laser scanning. Secondly, a laboratory study was performed using the samples gathered from the structure. The physical tests revealed that while the stone sample taken from the minaret had the highest porosity, the stone sample represents the west facade displayed the lowest porosity. Accordingly, the water absorption capacity of the stone sample taken from the west facade was the lowest. On the other hand, among samples, this stone sample had the highest wet and dry density. In the third step, the renovation process of the mosque considering its originality is presented. Lastly, the seismic performance level of the renovated structure is obtained using three analyses: linear, pushover, and kinematic approaches. Story drift ratios of the structure at the performance points for three earthquake ground motion levels meet the target performance requirements. Considering the realistic behavior of the material, the vulnerability of the main structure against the maximum credible earthquake is revealed in terms of tensile and shear stresses. The seismic vulnerability of the minaret is also determined in terms of both tensile and shear stresses and the story drifts ratios in both analysis types. We believe that the structural restoration processes presented in this paper to bring back a deteriorated historical mosque to its original form will provide a comprehensive approach to the literature.

This paper proposes a new type of fabricated shear wall system, that is, the two ends of the horizontally distributed ribs and the top of the vertical distributed ribs are reliably connected with the cast-in-situ belt, and the bottom of the vertical distributed ribs is not penetrated and only connected by mortar. To study the seismic performance of the new wall, 7 specimens of the shear wall were designed and manufactured, including 2 cast-in-place shear walls and 5 new fabricated shear walls. Through low-cycle reciprocating loading tests, different analyses were made. Shear span ratio and different edge restraint structure of the new fabricated shear wall failure mode, bearing capacity and other seismic performance, and through OpenSees finite element analysis of the wall to verify the correctness of the modelling method. The test results show that the failure characteristics of the new wall are mainly the cracking and penetration of the mortar layer, the crushing of the corner concrete and the local buckling of the steel bars at the bottom of the edge members; compared with the cast-in-place wall, the new wall has the lower bearing capacity, but the deformation and energy consumption are not much different. The reinforced edge members can effectively compensate for the weakening of the integrity of the wall panel caused by the discontinuity of vertical steel bars. Among the 7 specimens, the overall performance of the wall with increased longitudinal reinforcement ratio is the best. The error between the wall finite element results and the test results is less than 5%, which shows that the modelling method in this paper has sufficient accuracy for the evaluation of the seismic performance of the new wall. In general, the new prefabricated shear wall system is feasible in high-rise buildings.

A window wall is a lightweight external wall composed of glass and aluminium, which does not carry any gravity loads from the building except for its own weight. Wind load is transferred to the main structural system through the connections of sub-frames (consisting of sub-heads and sub-sills) with slabs. An aluminium sub-head with a removable bead (ASHWRB) is a common type of sub-head consisting of two parts: a base and a bead. Under wind load, the bead flange is directly loaded by the mullion and undergoes bearing failure due to its long length. This paper presents a detailed numerical study on the bearing capacities of the ASHWRB sections subject to wind loading. For this purpose, finite element models were simulated using ABAQUS/CAE and validated with our previously conducted experimental work in terms of ultimate loads, load-displacement curves, and failure modes. Validated finite element models of the ASHWRB sections were then used for an extensive parametric study covering a wide range of thicknesses, flange widths , bearing widths, and engagement lengths. Notably, the ultimate loads obtained from the parametric study are not product nor manufacturer specific, whereas, the data obtained from experimental study is specific to the manufacturer products. The acquired bearing database was used for a detailed assessment of the consistency and reliability of the previously proposed design rules by the authors (DRA) based on the experimental tests as well as currently available cold-formed steel design rules (DRSs). It was found that the bearing capacities determined by both DRA and DRSS are unreliable for predicting the bearing capacities of the ASHWRB sections in the window wall. Thus, modifications were made to DRA and DRSS. Consequently, new design rules were proposed in this paper (DRA P), which accurately predicted the bearing capacities and correlated very well with the numerical results.

The Ceara State, northeast of Brazil, has an acknowledged stock of heritage buildings located in the cities of Aracati, Sobral, Ico and Vicosa do Ceara. These Luso-Brazilian historical buildings are masonry structures dating from the 18th, 19th and 20th centuries and are important historical cultural assets. This way, the present paper has as the main aim to assess the structural vulnerability of facades of Ceara heritage constructions, namely the historic cities of Aracati and Sobral. This paper lists the recurrent and major damages of building facades and spatially maps the structural vulnerability results. For this purpose, a novel structural vulnerability assessment of the facades, focused on typical historical Brazilian masonries is presented. The procedure is based on the assessment of qualitative and quantitative parameters derived from the analysis and treatment of general information on the structure, such as geometrical characteristics, construction technology and material properties. The results show that information on the structural vulnerability of heritage buildings can be a relevant tool to support the design intervention plans as well to identify the critical situations in need of urgent conservation/retrofitting. This paper is a precursor to dynamic analysis in Brazilian historical centers.

The Hackitt Report into the tragic loss of 72 lives in the Grenfell Tower fire, identified failures and poor practices associated with the UK construction industry. To address these failures the report makes several recommendations, including the development of a “golden thread of information” to be embedded throughout the entire building lifecycle enabling the recording and preservation of information. This is to be achieved through Building Information Modelling (BIM). However, to create a “golden thread of information” in BIM from the Fire Safety Engineering (FSE) perspective particularly for the performance-based approach, many significant challenges and limitations must be resolved. These challenges include the fact that no FSE specific information exchange is available in BIM and that the results produced by fire and evacuation modelling tools are not explicitly captured in the BIM Industry Foundation Classes (IFC) Model. Of the FSE tools that support BIM, this is mainly limited to geometry extraction from an IFC file. In this paper, a practical conceptual strategy to pave the way to resolve these problems is proposed. A number of developments by the authors are discussed, forming part of an international collaboration project proposal administered by buildingSMART to enhance the IFC Model from the FSE perspective. Additionally, to evaluate and demonstrate the benefits of two-way data flow between BIM and FSE tools, a prototype system together with a preliminary FSE based analysis database have been developed. The work presented in this paper, provides a practical road map for creating a ‘golden thread of information’ in BIM for performance-based FSE analysis.

Bamboo is well known as a kind of environment-friendly and sustainable material with superior mechanical properties such as high strength to weight ratio . Generally, it is accepted that bamboo has wide application possibilities in the construction sector. In the present development of the processing technology, engineered bamboo has gradually entered the field of modern structural engineering since the beginning of present century. This paper proposed a novel sandwich panel composed of engineered bamboo face and aerated concrete core. Investigation and analysis of the mechanical properties of this novel engineered bamboo–concrete sandwich panel under axial load was conducted through experiments and theoretical equations. The influence of different factor like face type, thickness of face and core; connection type between the face and the core was discussed as well. The result showed that the bamboo face significantly affected the panel mechanical properties and demonstrated that the sandwich panel proposed in this paper is promising due to its distinguished recorded structural performance.

In order to reduce the energy consumption and improve the economy of air conditioning system, theoretical analysis and energy consumption simulation are used in this paper to explore the adaptability of temperature and humidity independent control (THIC) air-conditioning system in green office buildings. On the basis of the air moisture content and working hours of staff in green office buildings, China was divided into four humidity-hour zones, and several typical cities were selected in each zone for the same building to carry out the analyses of energy consumption simulation and dynamic recovery period of different THIC air conditioning systems in office buildings. The results indicated that in Urumqi, as the representative city of humidity-hour zone I, green office buildings do not suit THIC system; THIC air conditioning system shows obvious advantages over traditional air conditioning in terms of energy saving and economy, and the energy saving rate of the most suitable THIC air conditioning system in Harbin, Beijing and Haikou, as the representative city of humidity-hour zone Ⅱ, zone Ⅲ and zone Ⅳ, reached 28.04%, 24.64%, and 24.42% respectively. Based on the number of humidity-hour, the most suitable THIC air conditioning systems for typical cities in different zone were raised, and a reference for the use of THIC air conditioning system in green office buildings was provided in this paper.

Building management tools, such as building automation systems (BASs) and computerized maintenance management systems (CMMSs), are intended to support the efficient operation of building systems while maintaining occupants' comfort. However, observing current building management practices in commercial and institutional buildings demonstrates several challenges that compromise the core objectives of building management tools. To this end, this paper aims to provide recommendations to commercial and institutional building management stakeholders for improving current building management practices in North America. The recommendations are based on interviews with thirty building management professionals, examples and evidence from relevant literature, and the authors' involvement in resolving building management-related issues. The paper first documents current building management practices including professionals' backgrounds and qualifications, approaches and tools used, coordination, and building occupants’ involvement. Then, barriers to improving current building management practices are outlined including knowledge, technology, and organizational challenges. Finally, short- and long-term goals to improve current building management practices are outlined. This paper is intended to serve as a roadmap for improving building energy management practices for both researchers and industry.

Australia is facing an energy crisis, yet the solar resource is still underutilized. Government's support to small-scale residential solar photovoltaic (PV) systems undermines large-scale rooftop PV systems which are relatively overlooked, and their fully potential remains unexplored. This paper addresses the importance of implementing large-scale rooftop PV systems at airports precinct for energy planning and policy making. This paper aims to investigate the potential of electricity production of rooftop solar PV at 21 Leased Federal Airports (LFAs) in Australia. Specifically, we demonstrated a reproducible methodological framework including: (i) a low-cost data collection of 3D rooftop, (ii) a user-friendly solar radiation modeling in GIS, and (iii) accurate estimation of electricity potential from large-scale airport rooftop solar PV arrays. In addition, a comparison of rooftop solar PV energy productions between the LFAs and a local government area, City of Greater Bendigo, was conducted. The results show that estimated annual electricity potential from large-scale rooftop PV systems at 21 LFAs is 466.68 GWh, and nearly 10 times greater than the annual electricity generated with nearly 17,000 installed residential solar rooftop PV panels in the local government area. If the potential area of LFAs rooftops, currently 2.61 km 2 in total, were considered for solar PV, Australia could mitigate the energy crisis significantly to supply the equivalent of 136,000 homes and offset 151.6 kt of GHG emission annually. The outcome of this study not only opens the possibilities for more large-scale solar rooftop PV projects but also aids the authorities in their drive to lessen carbon emissions in the country.

The purpose of this paper is to examine and discuss the current patterns, gaps and trends in Digital Twin research in the architectural, engineering, construction, operation, and facility management (AECO-FM) industry and to propose future directions for industry stakeholders . A bibliometric search was performed on 197 papers that were obtained from the Scopus database. 151 of those papers were used in the subsequent scientometric analysis and mapping to narrate the evolution of the research subject. The studies discussed in the paper cover a wide range of research from model-based information management to building information management, all the way to the interaction between buildings and smart cities. The ‘virtual-physical building integration’, ‘building lifecycle management’, and ‘information integrated production’ subjects are highly in the focus of the research field. While ‘information-based predictive management’ and ‘virtual-based information utilization’ studies need to be addressed for a holistic Digital Twin adoption in the AECO-FM industry. Future studies should focus on the full integration of digital twin and its physical counterpart for better performance throughout the building life cycle. This study highlights the patterns, gaps and trends in Digital Twin research in the AECO-FM industry and contributes to the state-of-the-art digitalization and automation approaches in the construction project management body of knowledge. The sample size is a limitation for this research since it is relatively small due to the newness of the subject. Future studies may include data related to practice-oriented innovations and industry-initiated improvements to achieve broader and more informed results.

Applying any sustainable intervention in the urban energy system requires fundamental knowledge of the energy demand dynamics. Only when we can predict the users' energy demand at any given time with accuracy, we can redesign the urban energy system. Accordingly, the main objective of this paper is to determine the annual electricity usage of the building connections in the urban built environment. In this paper firstly through a literature review, the important electricity usage explanatory variables of the built environment are recognized. For each building, besides the annual electricity usage, three major categories of explanatory variables, including physical, socioeconomic, and geospatial characteristics are determined. Based on the available data sources, a building electricity usage database is created. The database is categorized based on the two most frequently used building sectors including residential and non-residential. Ordinary Least Squares (OLS) technique is applied to the constructed database to estimate the predicting model parameters establishing a relationship between the annual electricity usage as a dependent variable and physical, socioeconomic, and geospatial variables as independent variables. In this research, to determine the contribution of geospatial characteristics in the annual electricity usage variability, regression analysis is performed in two consecutive steps. In the first step only, the geospatial characteristics were implemented in the multiple linear regression analysis. Following that, in the second step, the other categories including physical and socioeconomic characteristics are added to the model. The result revealed that in both building sectors most of the predictors are statistically significant at the 0.05 level. While for the residential buildings the geospatial characteristics account for 9.7% of the electricity usage variation, these values for the service and industry sub-sectors are 9.9% and 8.7% respectively. In total, all variables explain 28.1%, 39.4%, and 42.9% of the electricity usage variability of residential, service, and industrial buildings respectively.

Masonry infill walls are the standard solution to build envelopes and partitions walls in reinforced concrete buildings in southern Europe. In Portugal, masonry infill walls appeared in the sixties, with the massive use of reinforced concrete frames for residential and commercial buildings. Since then and until our days the masonry infills walls (cavity walls) have not experienced significant changes, apart from some variations in thickness and introduction of thermal isolation between the masonry layers. The construction system remains based on cavity walls without any connection between layers and constructed with horizontal perforated bricks and poor mortars. Their vulnerability under seismic actions is recognized by the scientific community and proven whenever an earthquake occurs. Nevertheless, they continue to be used, because until now there was not much innovation in the development of attractive solutions to be implemented in new constructions, and particularly there are no clear design and detailing construction guidelines that can contribute to higher quality masonry infill walls with reduced seismic vulnerability. This paper aims to contribute for the advance on the innovation in brick masonry infills by presenting two proposals of new masonry infill walls systems to be enclosed by RC frames. An extensive experimental campaign is presented and results are discussed on mechanical properties of materials and masonry assemblages associated to the two innovative masonry infill wall systems. The data provided in this paper is important to understand further in-plane and out-of-plane experimental tests to be carried out on the masonry infill walls as well as further numerical simulations and analytical analysis of the masonry infill systems.

This paper presents experimental research about operation of a square-shaped membrane-type sag roof on a flat supporting contour. Membrane roofs include a thin metal shell (membrane) attached to the supporting contour. The membrane has the functions of structural support and protection, mainly resisting the stretching force. The supporting contour resists the compression force by bending in two planes. Eccentric fixing of the membrane in the contour gives rise to a torque. With torsion, the thin-walled open-profile contour develops additional normal tensions. Experiments were conducted on a test bench consisting of a base, a model and instrumentation. The membrane model is convertible: the same model can be used to represent four structural setups. The test have examined the effects of a load uniformly distributed over the surface of the roof, and of focused loads: vertical loads applied to the membrane (to emulate the effect of a suspension crane), and horizontal loads applied to the supporting contour (to emulate wind loads and loads created by support bridge cranes). Parameters of the test structure are such that they enable emulation of roofs spanning over 24 × 24 m and 36 × 36 m. The model's dimensions in plane are 3 × 3 m, with the supporting contour shaped as a channel bar welded of L-bar. The membrane roof model is manufactured of aluminum alloys. The paper places the main focus on the operation of a model with a membrane fixed eccentrically (to lower ledge of the channel bar) to the supporting contour. Performance of such roofs has been experimentally confirmed; the test revealed significant reserves of structural bearing capacity, small horizontal and vertical displacements of the supporting contour, and admissibility of plastic deformations in small sections of the contour. Experimental data are compared with calculated results from the computing system model. The calculations are carried out taking into account the constrained torsion of thin-walled open-profile rods.

The development of low energy buildings present new opportunities to develop HVAC products that works well with renewable energy sources. In this paper, we present a novel comfort system that combines a full radiant ceiling with diffuse ventilation into one flexible ceiling solution, HVACeiling. The purpose of the paper is to investigate how the combination changes heating and cooling performance and how the thermal storage cycle of the exposed slab in the closed plenum affects energy consumption and thermal comfort. The heating and cooling performance was investigated numerically in IDA ICE with daily based occurrence temperatures and compared to a reference with a radiant ceiling and mixing ventilation. The HVACeiling was a perforated gypsum board with pipes embedded that is used for diffuse ventilation and acoustical absorption as well as a radiant ceiling. Water was circulated day and night at fixed supply temperatures of 20–22 °C without any other controls. The convective surface heat transfer coefficients of the plenum was modelled in a preliminary CFD study and compared to literature and experiments. It was found that for daily based occurrence scenarios, with outdoor temperature in the range 23–28 °C, the heat exchange from the ceiling was increased 5–16% compared to the reference. The studies also disclosed improved thermal comfort, up to 1.5 °C lower peak operative temperature in the occupied zone down from 27.2 °C. This implies that thermal comfort is easier achievable with the HVACeiling, even with a small temperature offset that is well suited for renewable sources.

In this paper, a new steel plate shear wall with a reduced web section beam is proposed. The proposed model, including a middle link beam with elongated circle opening, offers advantages such as the ease to integrate building services within the floor zone resulting in shallow structural depth, reducing demands on columns and beam-to-column connections, increasing the ductility by forming Vierendeel mechanism around the opening, and changing the pattern and mechanism of yielding. To investigate the structural performance of this system, experimental and numerical studies were carried out. Five 1/3- scale specimens were fabricated and tested under quasi-static cyclic loading. Results indicated that the steel plate shear wall with middle link beam (ML-SPSW) specimens had stable hysteresis curves and experienced 3% story drift without any reduction in bearing capacity. All proposed models could tolerate 6% drift with about a 30% reduction in maximum achieved load without a sudden or significant drop in strength or stiffness. The energy dissipation and ductility capacity were superior and the gravity bearing system (columns) and panel zones remained intact until the end of cyclic loading. Furthermore, nonlinear finite element (FE) models of tested specimens were developed and verified against the experimental results. Numerical simulations and test results showed good agreement. In order to further ascertain the validity of the proposed system, supplementary results were obtained from numerical models. Finally, a parametric study and a design algorithm were proposed to determine the proper size of the beam perforation.

Portland-cement-based concrete is the principle material for military engineering construction. However, concrete structure is prone to catastrophic failure under blast loading, due to concrete's brittle fracture. Ultra-high ductile concrete (UHDC) has excellent tensile strain capacity which is close to the deformability of steel reinforcement, and ultra-high performance concrete (UHPC) has ultra-high compressive strength and hardness. It is expected that the combination of UHDC and UHPC should possess better blast-resisting capacity. This paper presents the dynamic performance of reinforced UHDC-UHPC panels under close-in explosion. Four reinforced UHDC-UHPC panels with different steel ratio were tested at scale distances ranging from 0.5 m/kg1/3 to 0.8 m/kg1/3. Reinforced UHDC-UHPC panels showed excellent resistance to back face spalling. The test results demonstrated the significant effect of scale distance and steel reinforcement ratio on the dynamic responses and characteristics of the panels, i.e., displacement, velocity, average acceleration, natural period and damping ratio. Moreover, the damage levels for the panels under close-in blast loading were determined.

The structural engineering practitioners often deal with natural hazards that generate a structural response that is dynamic in nature. The wind loads are long duration load types and their induced effects, especially for severe events, need to be predicted through analysis by efficient numerical nonlinear solvers. In this paper the nonlinear wind-induced effects on structures are predicted using a non-commercial software based on the 3D Force Analogy Method (3D-FAM). The wind loads consist of time-histories of pressure coefficients recorded at a large number of taps in the wind tunnel test for a model corresponding to an 80 m high prototype building. A considerable number of dynamic nonlinear analyses are performed for different mean hourly wind speeds and wind blowing directions. For each case, the inelastic behavior of building is monitored through and efficient complementary energy balance-based analysis and quantified in time-domain by damage indices at each section, element, story and structural level.

Improving the energy efficiency of Heating, Ventilation, and Air Conditioning (HVAC) systems is crucial to reduce buildings’ energy costs and their carbon footprint. HVAC systems are complex, large-scale structures with pure lag time and high thermal inertia. Although traditionally, physical-based methods have been used to model, control and optimise them, data-driven approaches have demonstrated to be more application relevant, easier to compute and better suited to handle nonlinearities. Based only on measured or estimated data, data-driven approaches are highly dependent on the quality of the used data. In recent years, the advances in Information and Communication Technology (ICT), decreasing hardware cost, and improving data accessibility, have allowed the collection and storage of a large amount of high-quality building-related data, allowing the development of more accurate and robust data-driven approaches, making them gain great popularity in HVAC applications. In this paper, a Systematic Literature Review (SLR) based on a database search is conducted to give an in-depth insight into the major challenges regarding modelling, controlling and optimising HVAC systems, making the especial focus on the capability of data-driven models to improve their energy performance while keeping the users’ comfort. The main results of the SLR highlight the importance of taking users’ needs into account when modelling, controlling and optimising HVAC systems to avoid their underutilisation. In particular, the increasing tendency to include users’ feedback into Model Predictive Control (MPC) loops and use easy-to-access technologies, such as WiFi and Smartphone Applications (Apps), to acquire users’ information suggests promising future research horizons.

Prefabricated structures are widely used in civil infrastructure, attributed to the advantages of environmental sustainability, easy in-situ operation, short construction period and low-cost. Beam-to-column connection is the critical component for the structural integrity of prefabricated structures, and the failure of beam-to-column connection might lead to structural progressive collapse under earthquakes. In this paper, a novel dual-functional replaceable steel plate damper was proposed for prefabricated beam-to-column joints to improve the mechanical behavior and earthquake resilience. The influence of different configurations for steel plate damper on the hysteretic behavior was analyzed experimentally and numerically. Results obtained from experimental and numerical research demonstrated that proposed steel plate damper successfully developed desired mechanical behavior. Moreover, the influence of different configuration details including width-to-thickness ratio of steel plates, weakened length and width of steel plates, gap between weakened steel plates and constrained steel sleeves, were investigated to optimize the mechanical behavior of steel plate damper, and the favorable construction configurations were recommended based on parametric analysis. In the end, the hysteretic constitutive model for steel plate damper was proposed based on considerable numerical analysis on FEA models and verified by means of comparisons between theoretical results, experimental results and numerical analysis.

Increasing the penetration of Renewable Energy Sources (RES), the heat pumps are an alternative solution to facilitate the integration of RES into district heating. To hedge against the intermittency of RES, the flexibility potentials of the thermal inertia of buildings are unlocked and integrated into power systems. This paper suggests a novel structure to control the mixing loop of residential heating systems supplied by electrically operated district heating. The Economic Model Predictive Control (EMPC) is proposed to optimize the heat demand of the buildings in response to electricity market price. The EMPC controls the temperature and flow rate of forward/return water in the mixing loop to minimize the energy consumption cost of households. The thermal dynamics of the buildings are modeled by 3-state differential equations to integrate the flexibility potentials of thermal inertia into the district heating. The approach optimizes the heat consumption of the building with multi-temperature zones. The Continuous-Time Stochastic Model (CTSM) is addressed to determine the thermal dynamics of the building using sensor data. Finally, a 150 m2 Danish test house with four temperature zones is simulated. The simulation results show that the suggested approach not only minimizes the energy consumption cost but also provides flexibility for the Danish Electricity Market.

The application of aluminum alloys in structural engineering is growing owing to their high strength-to-weight ratio, aesthetic appearance, and excellent corrosion resistance. And extensive studies on concrete-filled aluminum alloy tubular (CFAT) columns under axial compression have been widely conducted. Still, little information was reported in the literature regarding the behavior of CFAT columns under eccentric compression. In order to investigate the ultimate bearing capacity of 7A04-T6 CFAT columns under eccentric compression, experimental and numerical studies were conducted. Test results show that the failure mode of all tested specimens was overall buckling, and specimens exhibited excellent ductility. Based on the verified finite element (FE) models, the influence of concrete strength, eccentricity, and slenderness ratio on ultimate bearing capacity was discussed and analyzed. In the absence of design specifications for CFAT columns, the design rules for concrete-filled steel tubular columns provided by European (EC4) and Chinese (GB50936-2014) standards were adopted, and steel's material properties were replaced with those of aluminum alloy. Results indicate that the predicted strength by EC4 has a good agreement with test and FE analysis results in some cases discussed in this paper. However, the design formulae in GB50936-2014 overestimate the ultimate bearing capacity of 7A04-T6 CFAT columns. Based on GB50936-2014, modified formulae that can predict the ultimate bearing capacity of 7A04-T6 CFAT columns with less than 10% discrepancies were proposed.