The problem of adaptive semi-active control of transient structural vibration induced by unknown harmonic excitation is studied. The controller adaptation is attained by using a specially designed reinforcement learning algorithm that adjusts the parameters of a switching control policy to guarantee efficient dissipation of the structural energy. This algorithm relies on an efficient gradient-based

The level of reinforcement loads in a reinforced soil retaining wall is important to its satisfactory operation under working stress conditions since it basically determines the wall deformation. Consequently, proper estimation of the reinforcement load is a necessary step in the service limit-state design of this type of earth retaining structures. In this study, a force equilibrium approach is proposed

The autonomous control and communication are the key technologies for unmanned earthwork machinery, and vehicle control terminals with compatibility are essential. This research develops a smart terminal-box (T-box) compatible with various types of unmanned earthwork machinery (including bulldozers, graders, and rollers). The data encoding and decoding model for the T-box communication is formulated

In order to promote the resource utilization of coal gasification slag(CGS) solid waste, the use of modified coal gasification slag (MCGS) to replace the cement in the cemented backfill materials is an effective way to improve the utilization rate of CGS resources, reduce the backfill cost and reduce the environmental pollution of the cement industry. In this paper, the dosage of sodium sulfate (SS)

Outrigger is a typical lateral-force resisting component for supertall buildings, and high-performance outriggers with excellent energy dissipation have been widely studied to enhance the seismic resilience of supertall buildings. However, the residual displacement of the outrigger still limits the rapid repair of the structure after earthquakes. This paper puts forward a self-centering frictional

Construction and demolition (C&D) waste has caused various economic, environmental, and social problems. This paper investigates the potential of recycled concrete fine powder (RFP) as a supplementary cementitious material. The effect of RFP with different replacement levels on the properties of cement and the mechanism of action were explored from the physical characteristics, mechanical properties

This paper investigates the seismic behavior of Pingshenke Dou-Gong bracket under the overhanging and width direction. Two full-scaled Dou-Gong brackets of Yihe Hall are tested by the pseudo-static test. The effects of loading direction on the failure patterns, hysteretic characteristics, stiffness and strength degradation, energy dissipation, and deformation capacity of the whole model under the overhanging

Probabilistic assessment of the lateral behaviors of column-and-tie wooden frame (CTWF) with uncertainty in the gaps inside the wood-wood connections is significant for preventive protection of wooden structures. This typical kind of traditional wooden structure has connections such as the semi mortise-tenon (SMT) connections, penetrated mortise-tenon (PMT) connections, lintel-mortise (LM) connections

This paper presents a novel fuzzy adaptive jellyfish search-optimized stacking system (FAJS-SS) that integrates the jellyfish search (JS) optimizer, the fuzzy adaptive (FA) logic controller, and stacking ensemble machine learning. First, FA logic is incorporated into JS optimizer to construct an efficient metaheuristic algorithm for global optimization. The proposed algorithm is benchmarked against

Building thermal load prediction is of great significance for energy conservation in HVAC systems. Due to the visible and complicated time delay between influencing factors and building thermal load, ensuring the consistency of time variation between feature variables and load in prediction is challenging. In this paper, the time-shifting correlation of feature variables to building thermal load was

Epoxy resins are widely used as construction and repair materials. However, their bond with the concrete substrate under wet conditions is of concern as the loss of compatibility will lead to the failure of the bonded system. The reported study investigated the effect of surface moisture at the epoxy/cement interface using molecular dynamics (MD) simulation. The model of the interface was built using

This study aims to improve our current understanding of the seismic assessment of load-bearing unreinforced masonry (URM) systems by proposing a probabilistic computational modeling framework using the discrete element method (DEM). The main objective is to predict the structural behavior and capacity of URM walls with openings subjected to lateral loading, considering uncertainties in material properties

In this paper, three-point flexural testing was used to study the flexural properties of polyvinyl alcohol fiber-reinforced engineered cementitious composites (PVA-ECC) and carbon textile-reinforced concrete (CTRC)-layered composite plates. Taking the layer thickness of the two materials and the material type of the tensile plate surface as factors, eight research conditions were established. The effects

The addition of waste in building materials is a technical and economical alternative for modern construction. Self-leveling mortar (SLM) is a material used in floors because it is able to flow and fill a base area without using extra energy. The present studied SLMs using porcelain insulator waste (PIW) as partial and total sand replacement. Different methods were used to characterize the PIW (e.g

The construction industry is facing challenges from the hazardous nature of Ordinary Portland Cement (OPC) production as one of the main contributors to global warming and CO2 emission. Given its increasing demand, the need to replace OPC with sustainable alternatives for green concrete production is essential. The promising results of using Rice Husk Ash (RHA) in concrete mixtures as a supplementary

For concrete buildings, the tasks of maintenance and reconstruction will rapidly increase with time, and concrete breaking is one of the important technical processes. In this study, it proposed the water jet combined with mechanical cutter head breaking concrete technology, which has advantages in efficiency, safety and quality compared with mechanical breaking concrete buildings. To reveal parameter

This paper deals with an experimental investigation into the mechanical performance and microstructure characteristics of the cementitious mortars containing recycled waste materials subjected to acidic, neutral and alkaline environments. The recycled waste materials include glass, eggshell, iron and rubber powder in various amounts, namely 7, 14 and 21% by volume, as the replacement for ordinary Portland

The production of high-strength alkali-activated mortar and concrete by using waste materials instead of cement in order to reduce the amount of carbon dioxide released to nature in cement production is an important study that attracts the attention of researchers. In this study, self-compacting alkali-activated mortar samples were produced using boron waste (BW) and granulated blast furnace slag (GBFS)

In this study, the pore deterioration of multi-walled carbon nanotubes (MWCNTs) reinforced concrete specimens exposed to high temperatures was investigated by X-ray computed tomography (CT) technique from the mesoscopic level. Meanwhile, the effects of MWCNTs on mechanical properties and micromorphology of concrete were evaluated by a uniaxial compressive test and scanning electron microscope (SEM)

The drying of capillary moisture from structural concrete used in enclosed areas takes place by free convection characterized by low air velocity. The slow drying results in the persistence of an unsaturated state in concrete rendering it susceptible to deterioration. The study of critical process parameters, such as, mass loss flux, convective transfer coefficients, critical and equilibrium moisture

Concrete usage in recent decades has skyrocketed, which has led to immense pressure on the natural resources such as sand and aggregates involved in its production. The circular economy concept, i.e., usage and recycling of waste products, can be incorporated into concrete production to alleviate the overutilization of natural resources. LD slag is presently dumped as a landfill, aggravating limited

This article addresses the augmentation of existing building models by a priori not observable structures such as electric installations. The aim is to unambiguously determine an electric network in an incremental manner with a minimum number of local measurements, e.g. using wire detectors, by suggesting the next measurement. Different reasoning strategies, e.g. utilizing graph-theoretical algorithms

Abstract not available

A great attention has been recently paid to sustainability and efficiency in the field of civil engineering. In this context, structural optimization processes combined with shape grammar constitute an important tool to support the design phase of large scale structures. This paper proposes shape grammars for the topology optimization of grid shells and diagrid tall buildings characterized by triangulated

Unstructured and variable construction sites bring challenges that can be addressed with the adoption of the flexible earthwork scheduling problem (FESP), which requires consideration of mechanical parameters, automated construction techniques, and site constraints. This paper describes the use of the non-dominated sorting genetic algorithm (NSGA-III) for such problems, yielding better results than

In steel-reinforced concrete (SRC) structures, it is difficult to separate or recycle steel and concrete using traditional demolition methods, which create a large amount of construction waste. A green and recyclable technology for demolishing SRC structures by induction heating (IH) is proposed in this study. The magnetic field calculation model of the rectangular coil used in IH demolition (IHD)

The component failure of the spoke-wheel cable structures is a major concern among the present structural engineering community. This paper investigated the effect of component failure on the spoke-wheel cable structures through numerical and experimental studies. Firstly, a new simulation modification method was introduced based on the building information modelling (BIM) the three-dimensional laser

Cold-formed steel (CFS) framing shear walls has been widely used as the lateral force resisting system of light-weight steel structures. While the behaviors of walls have been numerically studied, there is a need to develop more convenient and efficient modeling strategies. In this paper, a simulation framework consisting of component-level to system-level analysis for the seismic evaluation of steel-sheathed

In this study, the influences of the activated carbon type and wet conditions on the nitrogen oxide (NOx) removal performance of foam composites were investigated. To this end, foam composites with interconnected pores and a large specific surface area were prepared using activated carbon and titanium dioxide (TiO2). Two types of activated carbon (palm and pitched-based) with different micropore structures

Internet data centers experience continuous annual cooling load compared to common buildings that experience seasonal cooling and heating loads. This study experimentally shows the effect of summer and winter seasonal optimum refrigerant charge amounts on the performance of the IDC cooling system. A methodology for determining the annual optimal refrigerant charge of the IDC cooling system using an

Structural optimization can lead to efficient designs for high-rise concrete buildings. However, the high computational cost of the structural analysis step hinders its application in practical cases. With regards to this problem, a novel hybrid optimization framework is developed in this study. Discrete variables, code-stipulated constraints and other construction requirements under multiple loading

In order to improve the economical deficiency of the traditional frame-core tube (FCT) structure due to the large tube area proportion, a new high-rise structure of the frame-distributed tubes-core tube (FDCT) is proposed based on the design concept of the distributed tube. Combining the distributed tubes with the rocking system, the frame-distributed rocking tubes-core tube (FDRCT) is further proposed

Mineral admixtures have been frequently used in magnesium potassium phosphate cement (MKPC) system to improve its performance and reduce preparation cost. This study proposes a new method of reusing red mud as a mineral admixture in MKPC. The mixing proportions and mechanical properties red mud-modified MKPC were optimized by response surface methodology, with emphasis on the microstructure and reaction

As one type of commonly used non-structural component in public buildings, suspended ceilings (SCs) may suffer severe damage or even collapse under earthquakes. However, convincing numerical simulation on the SC is scarce due to its strongly nonlinear behavior. A refined numerical model for SC with free boundary condition is developed based on a full-scale shaking table test in this study. Grid connections

Coincident design day (CDD) means the design day that considered the simultaneous occurrence of design weather elements and the correlation between design weather data and room parameters. The application of coincident design day will make the load calculation more accurate in the air-conditioning system design. However, since there are excessive possible combinations of the room parameters in practical

The combined use of solar energy and ground-source heat pump system may provide a reasonable solution to the energy crisis and low utilization efficiency of single energy. In this paper, a numerical model of a solar assisted hybrid ground-source heat pump (SAHGSHP) system composed of multiple types and lengths of borehole heat exchanger (BHE) array was developed. The effectiveness of this model was

Rooftop photovoltaic panels (RPVPs) implementation is one of the effective strategies to mitigate urban heat island and relieve urban energy demand with renewable energy resources, which is in need, especially during extreme heatwave events. However, the effects of RPVPs on cooling the urban thermal environment and saving energy have not been fully investigated in terms of RPVPs coverage (CV) and conversion

Despite a growing consensus on the urgency of addressing global warming, the practicality of accelerating the delivery of low-carbon buildings (LCBs) in high-rise high-density cities is still hindered by various interdependent and interrelated constraints. None of the previous studies systematically explored the interrelationships among the constraints. Therefore, this study aims to identify and assess

The extension of in-home time has boosted people's increase demand for comfortable indoor temperatures. This paper aims to propose a smart home-based temperature control framework based on deep learning and reinforcement learning to automatically control indoor temperature. The heat pump power and the ventilation system volume could be adjusted by the proposed framework to minimize costs while maintaining

Prefabricated underground stations (PUSs) have been gradually applied as a new approach to urban low-carbon development; however, safe service for the city over the entire PUS life cycle remains a crucial issue. This study therefore investigates the resilience of PUSs with a large-span roof structure in multi-hazard urban environments. A joint vulnerability function is established to represent the

Vertical alignment design is an important process for railway construction which fundamentally affects the infrastructure investment cost. Determining an optimized vertical alignment is a challenging task since the objective function is non-linear, non-differentiable, and quite unsmooth. Great efforts have been invested in solving the vertical alignment optimization problem and many methods have been

Concrete-encased-and-filled steel tubular (CEFT) columns can be potentially connected to concrete beams as well as steel beams. This study aims to develop a novel precast concrete (PC) construction method connecting the CEFT columns and PC beams. In the proposed method, partial openings were provided in the steel tube to facilitate bar placing and concrete casting at the joint. To investigate the seismic

The state of blinds and lights affects children's visual environment and comfort, however, there is a significant gap in research on the factors leading to the operation of blinds and lights in primary school classrooms. This study identifies and categorises the main drivers of operations on blinds and lights and investigates optimal light levels for children in primary schools. The study collected

Condensation is prone to occur in radiant cooling systems caused by moisture infiltration through doors and windows. Ensuring condensed droplets evaporate entirely at the end of the shutdown period is critical to the effectiveness of the new adjustment method for metal radiant panels, based on the principle that no dripping occurs. A numerical model of the radiant ceiling system validated by experiment

The building sector is the highest energy consumer and ranks first in terms of carbon emissions among all sectors. To address these issues, decarbonization and electrification in the building energy sector are two critical missions of the new US administration. For decarbonization, the new administration has set a target to reduce greenhouse gas emissions by 50–52% by 2030 and targeting a carbon-neutral

This paper investigated the effect of citric acid (CA), magnesium citrate (CM), and lithium citrate (CL) on the expansion property and hydration behavior of light-burned magnesia (LBM) cement-based materials. Setting time, linear expansion, hydration kinetics, thermogravimetric analysis, XRD and SEM were used to characterize the expansion and hydration performance of LBM cement-based materials. The

Energy piles provide an innovative strategy for exploiting geothermal energy in low-energy buildings, as they simultaneously provide energy for space conditioning and support structural loads. In addition to research efforts aimed at improving the energy efficiency of energy piles, a significant amount of CO2 emission from concrete production has been overlooked in energy piles’ application. This study

The elasticity modulus and hardness of various phases in 4-year-old Portland cement paste, cement paste containing fly ash, granulated blast furnace slag (BFS) or steel slag at low water/binder ratio were determined by the statistical nanoindentation technique. The influences of different mineral admixtures on mechanical properties of individual phases were comparatively analysed. The pores were not

Abstract not available

In order to solve the problem of low relative humidity in buildings and dispersion of existing heating and humidification equipment during the heating season in severe cold regions, a fan coil unit prototype with a humidification module was developed, and the heat is provided by an air source heat pump. The humidification module was made of parallel porous plates, which were infiltrated by the water

In heavily urbanised areas, the construction of tunnels underneath existing ones is unavoidable and much caution has to be exercised in both design and construction so as not to undermine the safety of the structure and vehicles. In this paper, a non-linear soil-tunnel interaction model is developed to evaluate the tunnel behaviour that is induced by a new undercrossing tunnel excavation. A barrel

In the presence of a water spray system, the fire-induced pressure losses in a road tunnel can change, but this effect is currently not considered in the design of longitudinally ventilated tunnels. In this study, theoretical analyses are combined with FDS modelling to investigate the pressure losses due to flow acceleration, stack effect and friction in tunnels that use a water mist or a deluge system

Industrial and government regulations on underground shaft steelwork operations require high maintenance standards; however, the design procedures are highly simplified, significant risk sources are not considered, and adequate reliability assessments are not involved. In this study, we deployed maintenance measurements of the guiding forces and corrosion loss for actual load effects and resistance

Excessive carbon dioxide emission leads to climate change and severely threaten social sustainability. A novel model for evaluating carbon dioxide emission in slurry shield tunneling is presented. Firstly, the carbon dioxide emission from a slurry shield tunnel during construction was calculated using the emission coefficient method. Then, for predicting carbon dioxide emission in slurry shield tunneling