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

This work investigates the influence of alumina modulus (AM) on the formation of high-magnesium clinker (w(MgO) > 5 %) and the morphological evolution of MgO and prepares clinkers with different MgO contents by using analytical reagents. High-temperature microscopy (HTM), thermogravimetric–differential thermal analysis (TG–DTA), X–ray diffraction (XRD), optical microscopy and backscattered electro

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

Carbonation of cement-based materials may lead to durability problems, so that it is necessary to find a way to reduce the effect of carbonation on concrete durability. This study investigated the effects of cellulose nanofibrils (CNFs) on the durability of carbonated cement-based materials. Two dosages of CNFs were used to prepare cement pastes and mortars. Before and after accelerated carbonation

The collision and friction between the coarse solid particle and the concrete surface are the main reason for the abrasion damage of concrete structures caused by debris flow. Fibre reinforcement can improve the shear resistance and toughness of concrete, however, their effects on debris flow abrasion mechanism are yet not well understood. In this study, the influences of the type and dosage of steel

In this study, a low-cost and industrially scalable graphene nanofluid additive (GNA) was incorporated into carbon fibre-reinforced cement mortar (CFRCM) to enhance its functionalities. The results indicated that the synergistic effect of the carbon fibres and the GNA significantly improved many properties of the cement mortar. For the CFRCM modified with GNA (G-CFRCM), the maximum increases in the

With the growing interest in foamed geopolymer manufacture, there is an increasing demand for tailoring these composites’ pore structure. The binary system of two surfactants offers a possibility for enhancing foam formation efficiency and stability in geopolymer paste, however, their effects are not well understood. The influence of binary system blends on pore formation, size, and distribution in

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

In-situ X-ray diffraction (XRD) is a powerful tool to assess the hydration of cementitious materials, providing time-resolved quantitative analysis with reasonable accuracy without disturbing sample. However, the lack of guidelines and well-established procedures for data collection and analysis is the limiting factor for spreading this technique. This paper discussed using in-situ laboratory XRD to

The low environmental impact of earth – or soil – materials makes them interesting alternatives to lower CO2 emissions from the construction sector. Nevertheless, since they are often stabilized with Portland cement, the improvements in technical performance come at an environmental cost. In this paper, we revisit a vernacular stabilization technique to formulate a trass-gypsum-lime binder aiming at

Fundamental reaction-transport models of Portland cement hydration have been difficult to refine and validate because of the challenge of obtaining accurate data on the reaction rates and solubility of the four major clinker phases. Here we provide the first measurements of the solubility product of cubic tricalcium aluminate (C3A) as a function of temperature between 10 °C and 40 °C. The measurements

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

To enhance the durability performance of Basalt Fiber Reinforced Polymer (BFRP) bar reinforced Seawater Sea Sand Concrete (SWSSC) structure components in the marine environment, this paper investigated the feasibility of reducing SWSSC alkalinity to improve its compatibility with BFRP bars. The low-alkalinity ternary mixtures are designed with ordinary Portland cement (OPC), silica fume (SF) and fly

Calcium silicate hydrate (C–S–H) is the main cement hydration product, providing the most mechanical strength to concrete structure. As per the previous studies of bacteria-based self-healing concrete using non-ureolytic bacteria, one of the main issues is that the amount of externally added calcium salt was restricted by the properties of carriers, limiting the content of precipitated calcium carbonate

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

In this paper, we present a novel finite element model to simulate alkali-silica reaction in a realistic concrete meso-structure. Application of the internal ASR loading leads to the evolution of multiple deviated cracks and corresponding macroscopic expansion. A particular crack-extension algorithm and a solution scheme provide numerical stability and allow to model complicated crack patterns while

The present study investigates the potential of carbonation-cured belite-rich cement (BRC) to resist magnesium sulfate (MgSO4) and sulfuric acid (H2SO4) environments. BRC mortar was submerged in 5% and 10% MgSO4 and H2SO4 solutions. The gains of the compressive strength and mass under MgSO4 environment significantly depend upon the buffer (unreacted belite phase) left in the specimen after 28 days

This work evaluates the influence of a CO2-saturated curing environment on thin (5mm thick) boards of magnesium silicate hydrated (M-S-H) cement composites reinforced with cellulose fibers (CF). The first stage of the work consists of the optimization of the curing temperature when samples are subjected to high CO2 curing conditions. By means of XRD, the optimal carbonation temperature was set at 45