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Precast concrete segmental bridges have the advantages of rapid construction speed, excellent quality control and low cost. The structural behavior of segmental bridges largely depends on the behavior of the joints between segments. In this study, a series of specimens with epoxied joints, were tested to assess shear behavior of box girder segmental bridges, under direct shear loading. The study parameters were: confining stress level, prestressing eccentricity, and the concrete compressive strength. Shear behavior, shear capacity, and crack patterns of the joints were investigated as well. Mechanisms of sequential shear failure and a detailed analysis of failure events are also presented. It was found that the shear capacity of the joints increased approximately 40% for each increased 50% of the confining stress. Eccentricity of prestressing force wasn’t affecting the elastic behavior of the joints, but its role was appeared obviously at the plastic stage. By increasing concrete compressive strength up to 70 MPa, the joint shear capacity can be increased significantly. The experimental results of the current study and results of other researchers were compared with design provisions. It was seen that the relationships tended to underestimate the shear strength of keyed epoxied specimens by an average value of 11.3%.

Rigid piles (e.g., concrete piles) have been widely used to improve soft clay for the rapid construction of embankments. In this study, a damage plasticity model that considers the brittle failure behavior of concrete and the frictional properties along cracks is proposed to study the progressive failure of rigid piles under an embankment load. The mechanical characteristics of piles in different locations have been analyzed. The results show that the essential failure mode for rigid piles is tensile failure, which is primarily governed by the distribution of the bending moment and the axial force within the piles. Pile rupture releases stress and causes a significant increase in the tensile stress within neighboring piles, possibly leading to the progressive failure of adjacent piles. Failure in the upper section of piles ultimately leads to the propagation of a slip surface and the global failure of the embankment. The parametric analysis indicates that increases in the pile stiffness and the embankment load result in a higher tensile stress within the piles and a change in the failure mechanism from shear failure to bending failure. In addition, a failure envelope is proposed to determine the failure mode of the piles.

Studying on the microstructural evolution of cement paste during hydration is of considerable significance for understanding its mechanism and designing such material in cement industry. With the use of microtomography and image registration, the four-dimensional (4D) microstructure of cement paste can be captured, thereby assisting material scientists in studying the hydration process in situ. However, as a challenging task, the construction of high-quality 4D microstructural image is remarkably impeded by image size, isotropy, and homogeneity. This paper proposes an image processing framework to construct 4D high quality microstructural image rapidly for cement hydration. This framework improves and accelerates microstructural image registration and enhancement by using bias field correction, temporal intensity calibration and fast image registration. Additionally, a partial information registration method adopting partial information on the spatial and phased scales, is proposed to improve the registration speed and accuracy. Furthermore, a multi-factor multi-layer particle swarm optimization is proposed to improve the optimization in registration. Experimental results indicate that the 4D high quality microstructural image can be constructed rapidly with promising precision.

The current pandemic has highlighted the need for rapid construction of structures to treat patients and ensure manufacturing of health care products such as vaccines. In order to achieve this, rapid transportation of construction materials from staging area to deposition is needed. In the future, this could be achieved through automated construction sites that make use of robots. Toward this, in this paper a cable driven parallel manipulator (CDPM) is designed and built to balance a highly unstable load, a ball plate system. The system consists of eight cables attached to the end effector plate that can be extended or retracted to actuate movement of the plate. The hardware for the system was designed and built utilizing modern manufacturing processes. A camera system was designed using image recognition to identify the ball pose on the plate. The hardware was used to inform the development of a control system consisting of a reinforcement-learning trained neural network controller that outputs the desired platform response. A nested PID controller for each motor attached to each cable was used to realize the desired response. For the neural network controller, three different model structures were compared to assess the impact of varying model complexity. It was seen that less complex structures resulted in a slower response that was less flexible and more complex structures output a high frequency oscillation of the actuation signal resulting in an unresponsive system. It was concluded that the system showed promise for future development with the potential to improve on the state of the art.

Gas injection volume is the key parameter of air drilling with raise boring machine, and the determination of the minimum gas injection volume is one of the key technologies to improve the drilling speed and shorten the drilling period. Based on the characteristics of raise boring technology, the construction technique of raise boring with air as circulating medium is studied, and the double-channel structural characteristics of direct circulation system are discussed. On the basis of summarizing and analyzing the principle and characteristics of the calculation methods, the minimum gas injection volume required for rock carrying in the engineering of air drilling with raise boring machine is calculated by using the minimum velocity method. The research results provide a basis for the design of drilling parameters and are of great significance for expanding the application range of raise boring method and realizing the safe and rapid construction of shaft.

Prospects of application of roller compacted concrete in hydro schemes of Ukraine are considered. The number of dams erected with application of roller compacted concrete is growing year after year in the world. Roller compacted concrete is an especially dry concrete mixture with decreased content of cement and increased content of pozzolana (fly ash). The broad physico-mechanical peculiarities of roller compacted concrete depend not only on its composition but also on technology of its laying and compacting in dam. Rapid construction of gravity dams with use of equipment for earth-moving works enables the more economic construction of protective embankments. Prospects of application of roller compacted concrete during erection and restoration of existing protective embankments in regions with increased flood hazard in the west of Ukraine are considered. The use of roller compacted concrete allows reducing construction deadlines by a factor of 2–3, and, in so doing, reducing the labor content by a factor of 4–5 at the expense of full mechanization of works. Decrease in content of binder in composition of roller compacted concrete by 30–80 kg/m3 favors decrease in heat release and, correspondingly, the occurrence of temperature contraction cracks, which in its turn favors economy during construction of hydro-technical structures of hydro schemes.

It is an important problem in the mine water disaster prevention and control to control the large passage moving water. Traditional grouting technology is to put coarse aggregate and fine aggregate downward first and then grouting treatment. But the aggregate and cement flow distance is long, consumption is large, cost is high, and easy to appear secondary water inrush. Centering on the technical difficulties in the rapid construction of the blocking body of the moving water passage, a water-blocking textile bag was invented. The purpose of blocking the tunnel water inrush was achieved by grouting inside the bag body, which fundamentally realized the rapid blocking of the large passage through water under the condition of moving water. However, the mechanism, water plugging law, and design parameters of water blocking roadway with textile bag are still unclear. In this paper, the slip law and stability of the textile bag in the moving water and the deformation characteristics caused by the dynamic water pressure are theoretically analyzed and simulated. Through theoretical analysis, the ultimate antihydraulic stress value of a textile bag of a certain specification is calculated, and the parameters of the textile bag that affect the stability of the bag body are also determined. Xflow was used for numerical simulation analysis to study the deformation characteristics of the textile bag under water and the law of water barrier. The simulation analysis focuses on the water resistance effect and flow field distribution characteristics of the textile bag in the water passage under the condition of low flow rate and low pressure, as well as the stability and self-deformation characteristics of the textile bag under the condition of high flow rate and high pressure. The accuracy of the limit resistance to water pressure of the textile bag obtained from theoretical analysis is verified. The results show that the theoretical analysis is consistent with the simulation results. The textile bag can realize the fast controllable plugging of the large water passage of moving water within the limit of the antihydraulic stress.

The growing Chinese population and rapidly developing economy have led to the fast growth of the number of motor vehicles and the increasing types of road users, challenging the management of traffic safety. China has seen a continuous decline in traffic accidents and higher road traffic safety thanks to an improved system of road traffic management laws and regulations, the rapid construction of road traffic infrastructure, and the application of new technologies in public transportation. However, road traffic safety in China faces challenges. On one hand, typical traffic violations such as speeding, overloading, driving under the influence (DUI), and running a red light still exist. On the other hand, new forms of business and new technologies have complicated traffic management in China.

The rapid construction of tall buildings and long span structures demands the use of sustainable material in cement composition. Therefore, sustainability of concrete can be achieved by reducing the raw materials of concrete and improving its mechanical properties when non-conventional and low-cost materials are added. The main parameter of this study is to investigate the potential of PPF in enhancing the flexural strength of concrete experimentally, and it is expressed by a parameter fiber index. Moreover, an analytical model was derived to predict the flexural strength of the PPFRC prisms/rectangular section. In the experimental study, fibrillated polypropylene fiber concrete mixtures of two different lengths (Lf) 20 and 6 mm of polypropylene fibers with added at 0.5, 1, 1.5 and 2% volume fractions (Vf) were prepared. Three-point bending tests were performed on beams of 100 × 100 mm cross section and length of 510 mm at 28 days standard curing. The final results of experimental test are substituted in this derived model for the determination of the flexural strength of PPFRC members. The flexural strength of PPFRC specimens increased as compared to plain concrete and has proven to reduce plastic waste in environment.

Rigid piles are used to alleviate the detrimental characteristics of soft soil. Recently, the use of piled embankments has increased by many folds, as it facilitates rapid construction without compromising on serviceability. In the piled embankment, soil arching mechanism between adjacent piles improves the load-transfer to the piles and reduces the stress applied to the soft soil. In this study, a two-dimensional plane strain finite element model is adopted to investigate the mechanism of soil arching in a piled embankment. An idealized unit cell model is used to simulate the pile-supported embankment. The effect of different characteristics of piles and embankment soil are assessed. The outcome shows that friction angle, and embankment modulus significantly affects soil arching. Inconsistency among existing design approaches in the literature is highlighted.

The rapid development of big data has attracted extensive attention at home and abroad. Scientific and effective analysis and processing of big data is the core issue in the field of big data. The construction of a big data analysis platform in cloud environment can process complex data structures and highly correlated data, timely respond to user requests, realize intelligent and efficient data analysis, and mine more valuable data, providing technical support for the rapid construction of big data services.

Trapezoidal-shaped thin-walled metallic profiled sheets are used in composite floor construction to enable rapid construction and reduce reinforcement and formwork requirements in concrete casting. However, relevant literature reported the early failure of steel sections due to the buckling and shear of existing trapezoidal and re-entrant decking profiles. There are also limitations regarding design rules for composite flooring systems. Current work aims to develop a new type of composite top-hat section for possible use in composite slim-floor construction. Sinusoidal metallic corrugated sheets that are widely used in building construction were utilized and a new bending technique was used to produce deck components, in which transverse corrugations were introduced along the main direction of the corrugated profile. This paper investigates the structural response of these new sections for several loading and support conditions using a pilot experimental scheme. The developed top-hat sections demonstrated considerable resistance to bending as well as buckling through effective stress re-distributions under considered construction stage loading for single span and continuous span conditions. Currently available design equations recommended by Australian Standards for a similar type of corrugated decks were used to predict the design strength and to compare it with those obtained experimentally. It was concluded that the expressions proposed by the code were inadequate for single span loading cases and would require modifications before being applied to the new profile.

To eliminate voltage violations and improve the security and economy of wind farms, model-based volt/var optimization has been widely but heavily relies on accurate wind farm models. However, numerous wind farms lack of well maintained models because of rapid construction, limited operation staff and changing environment. It motivates us to develop a data-driven wind farm volt/var control based on deep reinforcement learning (DRL). In order to improve the stability, efficiency and optimality of existing DRL-based methods, entropy-regulation technique is utilized. Numerical simulations not only demonstrate the effectiveness of such data-driven volt/var control method, but also show the superiority of our proposed method.

The world economy is surging and newer technologies are evolving with the time. The construction sector is about to undergo a huge transformational change. The people of the world are looking forward to residing in houses made of sustainable materials. The people are concerned about increasing levels of greenhouse gases in the atmosphere. The cement production is accompanied by huge greenhouse gas emissions. On the other hand, waste plastics are becoming a nightmare for the people residing in developed and underdeveloped countries, as the waste management becomes difficult in those places. This research discusses a potential solution to address the above-stated issues of concern, i.e., plastic waste into construction blocks with lower cost and rapid construction phases. A study was conducted to examine the effectiveness of using LDPE (Low-Density Polyethylene), (major sources of waste and least recycled plastic) with waste materials like bottom ash, copper slag, and ceramic in different proportions to create blocks. This study compares the mechanical properties of different mix proportions of raw materials to find an optimum composition. This paper also investigates the pre-eminence of the newly developed composite block over the conventional brick in terms of economic viability, environmental sustainability, and construction superiority.

A common training simulation system is proposed for the general-purpose and efficient control training needs of the mid-and high-end military UAV system. The general modeling technology and process-configurable interface protocol modeling method are adopted to realize the rapid construction of flight simulation subsystem of various aircraft models. A scheme based on general bus monitoring and fast extraction equipment is designed to realize the fast embedded real-time control training of UAV with different physical devices. A self-correctable control and evaluation method of UAV training based on multi-sample statistics is proposed to enhance the targeted strengthening setting of training subjects for trainees, so as to improve training efficiency and training effect.

A well-planned and socially inclusive city provides an unprecedented opportunity to transform its challenges like urbanization, management of infrastructure, etc. to a smooth sustainable transformation. The implementation a material technology like Glass Fibre Reinforced Gypsum (GFRG) in construction also links itself to the important Sustainable Development of providing affordable housing for all (besides its other possible applications). This technology involve greater thought in planning and rapid construction of quality eco-friendly homes. Thus, weighing the advantages, uses, and shortcomings of this gypsum composite material through key governing attributes, the technical, economic, and social implications of this perspective solution for mainstream construction challenges were theoretically discussed. Further, the reasons for its limited practice in the Indian industry, user satisfaction, and challenges in the incorporation of this technology were also studied and compared with the conventional methods of construction in our point of view.

Aiming at the requirements of shortening the process design cycle and improving the design efficiency in the microassembly process, the study proposes a rapid 3d process design system based on microassembly process data. An object-oriented method is used to construct a microassembly process data model, so that the data from design department and history process can be described and managed. Then, the rapid construction method of the microassembly process model is described in detail based on the microassembly process data, including the rapid reuse of assembly process, automatic generation of assembly sequence and path, simulation and optimization of key processes. Finally, the above methods are integrated into a three-dimensional assembly process design system, and a microassembly product model is taken as an example to verify the effectiveness of the design system.

A method for the rapid construction of meshes over intersecting triangulated shapes is described. The method is based on an algorithm that automatically generates a surface mesh from intersecting triangulated surfaces by means of Boolean intersection/union operations. After the intersection of individual components is obtained, the exposed surface parts are extracted. The algorithm is intended for rapid interactive construction of non-trivial surfaces in engineering design, manufacturing, visualization and molecular modelling applications. Techniques to make the method fast and general are described. The proposed algorithm is demonstrated on a number of examples, including intersections of multiple spheres, planes and general engineering shapes, as well as generation of surface and volume meshes around clusters of intersecting components followed by the computation of flow field parameters. Copyright © 1999 John Wiley & Sons, Ltd.

Digital manufacturing has transformed many industries but has had only a limited impact in the construction sector. To capitalize on advanced manufacturing techniques, this paper introduces a radically new connection approach for gravity structural steel frames. The proposed intermeshed steel connection (ISC) exploits robotic abilities to cut structural steel member ends precisely to accelerate deployment and offer better disassembly options over existing approaches. Forces are transferred through common bearing surfaces at multiple contact points, and connections can be secured by small locking pieces. This paper introduces the geometry, manufacturing, and initial analysis and test results of the connection. The paper demonstrates the ability of the connection to (1) be manufactured within current industrial tolerances, (2) be erected and disassembled, and (3) perform at expected design levels.

Use of precast concrete pavement (PCP) for rapid construction of roads has gained high popularity in the last decade. In this technology, precast pavement panels are cast in a precast yard,...

Based on the traditional hanging basket cantilever construction of the prestressed concrete box girders, combined with the excellent shear capacity of the corrugated steel webs (CSWs), this...

With the rapid construction of the high-speed railway in China, the operational efficiency and revenue performance are getting more and more attention from operators. In this paper, the idea of revenue management is adopted to adjust the passenger flow of parallel trains through differential pricing considering the preference of passengers for different parallel trains. Based on utility theory, the Multinomial Logit model is used to describe passengers’ choice behavior among parallel trains, and a cooperative optimization model for ticket price and seat control of high-speed rail network with multi-train and multi-stop stations is established. At the same time, the optimization strategy of differential pricing and seat control of parallel trains is obtained. The validity of the model is proved by numerical experiments based on the train of Beijing-Shanghai high-speed railway. The optimization polices of this model in this paper can provide optimization strategy for the revenue management of high-speed parallel trains and enrich the synchronous optimization theory of capacity control and pricing in revenue management.

Asphalt pavement has been extensively used in expressways all over the world because of its many advantages such as rapid construction, easy maintenance, driving comfort and safety, low noise levels, etc. However, some disadvantages of asphalt pavement cannot be ignored. As an organic substance, asphalt is vulnerable to aging due to the influence of thermal, oxygen, light, water, and other external factors, which can cause distress such as potholes, cracks, loosening, and shortened service life. Therefore it is important to improve the road performance of asphalt materials. With the development of nanotechnology, some inorganic nanomaterials such as layered silicates and inorganic nanoparticles have been applied to improve these performances of asphalt road construction materials. As these inorganic nanomaterials are hydrophilic while asphalt material is lipophilic, the compatibility between inorganic nanomaterials and organic asphalt is poor. In order to enhance this compatibility, these nanomaterials need to be functionalized by using surfactants. After functionalizing, the application of inorganic nanomaterials in asphalt road materials becomes more extensive. This chapter mainly includes three sections: First, we cover applications of organic layered silicates in asphalt; secondly, applications of surface modification inorganic nanoparticles in asphalt; thirdly, applications of multidimensional nanomaterials in asphalt. The chapter finally outlines likely future trends on the application of functionalized nanomaterials in asphalt road construction materials.

Road users in California have a low tolerance for delays during pavement rehabilitation. Therefore, the California Department of Transportation (Caltrans) is interested in evaluating bonded concrete overlays on asphalt (BCOA) as a potential rehabilitation alternative for distressed asphalt pavement. The use of high early strength concrete to facilitate rapid construction of BCOA has not been used in other U.S. states. This paper summarizes a complete study for the evaluation of concrete mix designs for rapid construction of BCOA that were placed on a set of full-scale test sections for accelerated pavement testing. Two types of mixes were created according to selected targets for opening times (OT) to traffic. The concrete mixes for use in night closures require an opening time of four hours, and the mixes for use in 55-hour weekend closures require an OT of 10 hours. Type III Portland cement and calcium sulfoaluminate (CSA) cement were used to design the 4H-OT mixes. Two 10H-OT mixes were designed using the same Type II/V portland cement. One of the 10H-OT mixes included light weight aggregate instead of a portion of conventional sand to evaluate the effects of this approach for internal curing to reduce drying shrinkage stresses.

Orthotropic steel decks have been applied after World War II to long-span bridges due to several advantages, such as light weight, high strength, rapid construction, durability, and life-cy...

This study developed a powder feeding laser metal deposition (LMD) method that can be used to achieve a layer-by-layer fabrication of component grade material for efficiently screening the properties of different chemical compositions and determining the optimized composition range for TRIP stainless steel. The 13Cr-xNi-(10-x)Mn-3Al steel with continuous graded composition was produced by the LMD method. An optimized composition range for TRIP stainless steel was determined by testing the properties including hardness, austenite content and surface potential of positions with different compositions. The suggested Ni content is between 3%–6% and Mn content is between 4%–7%. This study demonstrates the potential of LMD method to accelerate the development of steel economically. Keywords: Component gradient, Layer metal deposition, Layer by layer

The United Nations currently estimate that 860 million people live in slums, which is 12% of the world's population. The issue is usually focussed on a lack of funds, with individuals and governments. Thus, a need to develop low-cost housing alternatives is apparent, to make housing more affordable to the poor. The project described in this paper is the design of a low-cost home, that incorporates sustainable materials and shell vaults. The materials used to construct the home are cement stabilized earth blocks (CSEB), and blocks constructed of recycled building rubble. The walls of the home are dry-stacked (no mortar), to reduce material cost and enable rapid construction. The roof of the structure comprises two catenary shaped arches, which eliminate the need of roofing materials and doubles the living space. The design of the arches is given in detail, using a segmental equilibrium method of analysis. The segmental equilibrium method predicts the thrust-line for different combinations of loads, which are kept within the middle third of the vault walls. Various other aspects of the design are also described, such as the foundations, floor slab and the support system at the base of the arch.

Editor’s note: This article presents an approach toward rapid construction of empirical arrival curves—a widely used abstraction for modeling temporal workloads in real-time systems—from the execution traces. —Tulika Mitra, National University of Singapore —Jurgen Teich, Friedrich-Alexander-Universitat Erlangen-Nurnberg —Lothar Thiele, ETH Zurich

The Diels-Alder reaction strategy that can rapidly extend the conjugated backbone was applied to facilely synthesize fold-line, coplanar BN-embedded polycyclic aromatic hydrocarbons from simple small BN compounds. The molecular structures and packing modes of these BN-embedded acenes were confirmed by single-crystal X-ray diffraction. Their electronic and photophysical properties were studied by using UV-vis, fluorescence spectroscopy, electrochemical cyclic voltammetry, and density functional theory calculations. These results demonstrate the efficiency and feasibility of this synthetic strategy.

With the rapid construction of UHV AC-DC interconnected power grids, it is increasingly important to ensure the voltage stability of interconnected systems. In this paper, a continuous power flow algorithm for voltage-source converter (VSC) AC-DC system considering static load characteristics is proposed. It establishes an index for evaluating voltage stability based on the load margin and identified the weak region of the system. The effects of load model changes on voltage stability (VS) are analyzed in various scenarios. The relationship between DC control mode and system VS is further considered. The effectiveness of the proposed method is verified by an improved 10-node example.

Aiming at the problems that the construction process of distributed hardware-in-the-loop simulation (HILS) system is tedious and inflexible due to the lack of general architecture, and the previous distributed simulation architectures cannot meet the dynamic interactive relationships, a general architecture of distributed HILS supporting dynamic interactive relationships is developed. Based on this architecture, a rapid construction of distributed HILS systems can be carried out. The architecture supports the dynamic change of the data sending and receiving relationships in the distributed simulation. After testing, the architecture can support the real-time advance of distributed HILS in 1 millisecond step and meet the requirement of millisecond delay in data sending and receiving.

Drift-sand layer is a common weak stratum in mine construction. The construction of the shaft passing over the drift-sand layer is very difficult. Traditional construction method faces many problems such as long construction period, high construction cost, poor working environment, and uncontrollability of the support effect. In view of the loose and fragile rock mass with great deformation of sinking and driving engineering penetrating drift-sand layers in coal mine, the reaction mechanism and shortcomings of conventional chemical grouting materials were analyzed. New-type polymer grouting materials were prepared with catalysts and vinyl epoxy resin, which was made from epoxy resin. A comprehensive chemical grouting construction technology was proposed, which comprises initiative closing, concentrated bypass flow, water plugging priority, and secondary sand curing for the inclined shaft passing over the drift-sand layer. Results show that new-type polymer sand-cured materials have lower viscosity, better grout ability, and fire resistance, and the solidified material has stronger bonding strength and better deformation resistance compared with traditional chemical grouting materials. The engineering application effect is very prominent in controlling water burst and leakage at the drift-sand layer; thus the on-site comprehensive construction progress and safety are guaranteed.

Composite box girders with corrugated steel webs and trusses is a new type of advanced bridge structure proposed recently. This kind of structure consists of a top concrete slab, corrugated steel webs and two bottom concrete-filled steel tubes connected by trusses. The resistance to torsion and overturning of this kind of structure is larger than that of composite bridges with a single concrete-filled steel tube. This kind of structure is able to satisfy the requirement of rapid construction, environment protection and cost effectiveness. Two composite box girder bridges with corrugated steel webs and trusses have been or are being constructed in China. This paper presents the design of these two bridges in detail, which will provide valuable engineering experience for the further promotion of this kind of new bridge structure. Experimental research has been carried out to study the flexural behavior and the flexural capacity of this kind of new bridge structure. The test results show that when the test beam is at the elastic stage, the cross-section can be viewed as a plane section if only the strains of the concrete top slab and the bottom steel tubes are considered. The test beam shows good ductility throughout the whole loading process.

With the rapid construction of the ubiquitous power internet of things, the increasing demand of embedded hardware usage and the complex usage scenario of the embedded platform hardware in intelligent terminal. A more efficient vitalization solution was demanded. With the analysis of traditional virtualization solutions and the armv8 architecture embedded platform hardware support for virtualization, the implementation details of arm embedded platform supporting containerization technology are described. In particular, the specific steps of application containerization are introduced. In the end, we analyze the performance that application run in container and discuss future research directions.

The successful completion of the Zhengzhou–Xi’an high-speed railway project has greatly improved the construction level of China’s large-section loess tunnels, and has resulted in significant progress being made in both design theory and construction technology. This paper systematically summarizes the technical characteristics and main problems of the large-section loess tunnels on China’s high-speed railway, including classification of the surrounding rock, design of the supporting structure, surface settlement and cracking control, and safe and rapid construction methods. On this basis, the key construction techniques of loess tunnels with large sections for high-speed railway are expounded from the aspects of design and construction. The research results show that the classification of loess strata surrounding large tunnels should be based on the geological age of the loess, and be determined by combining the plastic index and the water content. In addition, the influence of the buried depth should be considered. During tunnel excavation disturbance, if the tensile stress exceeds the soil tensile or shear strength, the surface part of the sliding trend plane can be damaged, and visible cracks can form. The pressure of the surrounding rock of a large-section loess tunnel should be calculated according to the buried depth, using the corresponding formula. A three-bench seven-step excavation method of construction was used as the core technology system to ensure the safe and rapid construction of a large-section loess tunnel, following a field test to optimize the construction parameters and determine the engineering measures to stabilize the tunnel face. The conclusions and methods presented here are of great significance in revealing the strata and supporting mechanics of large-section loess tunnels, and in optimizing the supporting structure design and the technical parameters for construction. Keywords: Loess tunnel, Surrounding rock classification, Surface cracking, Design load, Three-bench seven-step excavation method

One approach to making modern structures more economically and environmentally sustainable is designing and constructing them to be adaptable to rapidly changing markets and building occupancies. At the same time, these structures are required to be resilient to seismic events. As a step towards meeting these goals, a lightweight, two-way, rapidly constructible and reconfigurable modular steel floor (RCRMSF) system has been developed. The system is fabricated from light-gauge steel plates sandwiching a grillage of orthogonally arranged cold formed Z-purlins, can span 9.1 m x 12.2 m, requires only girder supports, and fits within current steel construction framework. This study investigates the seismic behavior of the RCRMSF diaphragm through the use of high fidelity nonlinear finite element (FE) models. Six full-scale cantilever diaphragm models have been developed to study the effect of varying RCRMSF configurations and end support details. Both monotonic and cyclic loading protocols are used to determine the stiffness, strength, energy dissipation capacity, and general hysteretic behavior of the diaphragms. Based on the FE models, the behavior of the RCRMSF diaphragm is influenced primarily by the plate thickness and perimeter connection detail to the supporting steel frame. Overall, the RCRMSF has adequate diaphragm stiffness and strength, and shows favorable energy dissipation capacity due to its post-peak inelastic behavior. This observation implies that the RCRMSF can serve as an alternative solution to current seismic design and construction practices.

This paper reviews several key issues related to the use of natural aggregate (NA) for concrete production, in view of the high demand for materials to meet the rapid construction development in Malaysia. The current paper aims to discuss the potential of recycling waste concrete to generate recycled aggregates (RA) that may be used as alternative aggregate sources in the production of concrete. Moreover, several major challenges to the use of RA for concrete production are also highlighted. This paper also provides an action plan to encourage the construction industry’s wide usage of RA to achieve sustainable construction.  Keywords: construction; recycled aggregate; sustainable; waste concreteeISSN 2398-4279 © 2018. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.Â

With the development of computer hardware and virtual reality technology and its head-mounted display (HMD), the scale of the virtual environment that it can simulate is also growing, and related fields include forest simulation, virtual agriculture simulation and so on. However, it is urgent to solve the problem of slow construction speed of the scenes which include different kinds of three-dimensional models in the engineering practice. Aiming at the problem of crops planting by blocks in regular regions, a virtual scene construction method based on improved K-means clustering algorithm is proposed. For crops planting problems in irregular regions, we adapt the idea of visually adjusting the key points in regional boundaries to determine the region of planting crops in the virtual environment, proposing a rapid construction method of virtual scene based on Catmull-Rom Spline and Even-Odd Algorithm.

Herein, gas bubbles generated in situ from precursors assist the rapid construction of hollow sycamore fruit-like CoMoO4 spheres (HSCSs). This bubble-assisted fabrication strategy is easy to operate, ultra-fast, low cost and post-treatment-free, showing great potential for the large-scale production of HSCSs. The growth mechanism of HSCSs is discussed to reveal the evolution process, which may be generalized to the construction of a series of hollow ternary Mo-based oxides. The obtained HSCSs exhibit a superior specific capacitance and outstanding cyclic stability when applied in supercapacitors.

The construction of the ABC tricyclic skeleton of malabanone A with the required 4 stereocenters was accomplished in a concise route starting from R-carvone. The synthesis featured an intramolecular [3 + 2] cycloaddition reaction to assemble its A ring and an intramolecular Diels-Alder reaction to construct its C ring.

To attain sustainability and resilience goals in construction, there is a great need for lightweight and high-strength panel elements with simple and rapid construction, and enhanced heat insulation and sound attenuation . Accordingly, this study explores the seismic performance of novel prefabricated autoclaved aerated concrete (AAC) panel-walls that satisfy the above sustainability criteria. The corresponding failure process, load versus displacement, hysteresis behavior , stiffness skeleton, degradation curve, and ductility coefficient of the AAC panel-wall specimens were analyzed. Different design parameters including the size of the splicing panels, reinforcement, and constructional column settings were investigated and compared to the behavior of benchmark block walls. The experimental findings indicate that: (i) compared with the benchmark block walls, the AAC panel-walls had higher seismic shear capacity; (ii) the size of splicing panels did not affect the stress distribution, failure pattern, seismic shear capacity, and ductility of the panel-wall member; (iii) the in-panel reinforcement can make the stress distribution in the wall more uniform, increase its seismic shear capacity, reduce the rate of stiffness degradation , and enhance the wall ductility; (iv) and using constructional columns can enhance the ultimate load-bearing capacity of the wall. The construction of the panel-wall is convenient. Its seismic and shear performance are suitable for practical engineering applications.

Cold plateau areas are mostly remote, with harsh climatic conditions and no municipal energy supply. In case of disasters such as fire, earthquake, avalanche and epidemic, new houses or hospitals need to be built, and transportation difficulties, long construction cycle and energy shortage will be encountered. Therefore, prefabricated lightweight components, on-site assembly, combined with solar energy and wind energy to achieve energy self-sufficiency of prefabricated net zero energy building has become a feasible way to solve this problem. The purpose of this paper is to combine the advantages of existing prefabricated buildings and zero energy buildings, and to design and build a modular building with rapid construction and energy self-sufficiency in the cold plateau area, so as to meet the special needs of the extraordinary period. The building is composed of a steel structural frame and an envelope sheet. During the test period, the average temperature difference between indoor and outdoor was 25.3℃, and the maximum temperature difference was 42.3℃. The maximum daily power consumption is 23kWh, which can ensure that the temperature in the personnel activity area is kept above 15℃. The annual heating load per unit area is calculated as 7.3kWh/(m2·a), which is lower than the current standard of zero-energy buildings in the world.

To solve the seepage problem of roller-compacted concrete (RCC) gravity dams, grout-enriched vibrated RCC (GEVR) and immersion vibrated RCC (IVRCC) have been widely used as the primary impervious materials. However, the vibration process required for these materials severely impedes the rapid construction of RCC dams. To reduce the construction disturbance on RCC impervious structures, we propose a new type of self-compacting concrete (SCC), namely, high-fluidity impermeable and anti-cracking concrete (HIAC). HIAC is formed by partially replacing cement with an equal amount of expansion agent and by adjusting the mixture proportions through trial testing. The comprehensive performance of HIAC was studied using tests on its compressive strength, elastic modulus, permeability and, in particular, the mechanical properties of the interface between HIAC and RCC, using a large roller-compacted specimen. The results indicated that HIAC meets the basic requirements of hydraulic concrete. The compressive strength reached 1.52 times the design strength, and the permeability grade of the HIAC was greater than W34. In addition, the interfacial properties between HIAC and RCC were favorable. Relative to RCC, higher splitting strength was measured at the interface of HIAC and RCC. Therefore, using HIAC as the impervious material instead of GEVR facilitates simpler, faster and higher-quality construction. These advantages signify that HIAC is a promising material in hydraulic engineering.

Precast structural walls are commonly adopted as lateral load resisting elements in buildings, owing to improved quality and rapid construction. However, they suffer demerits in terms of weight and joint connections, which have strong influence on global behaviour of the building and calls for detailed investigation. This paper evaluates behaviour of two different types of precast reinforced concrete structural wall systems viz. precast wall-column system and precast double leaf system. The former comprises a precast wall connected with precast hollow columns through loop bars, while the latter comprises two precast panels with hollow core, which is casted with in-situ concrete. Both the wall systems were subjected to lateral load under displacement controlled cyclic mode and hysteretic characteristics were assessed in detail in terms of damage pattern and various seismic characteristics. Quantified performance limits were co-related with the performance acceptance criterion specified in codes. Finite element numerical analysis was executed to verify and compare the behavior of developed precast structural wall systems with the experimental results. No significant damage in precast wall-column system was observed, except few flexural cracks and separation at wall-column joint. Precast double leaf system experienced severance near the toe region along with uplift of precast panels, while the wall surface was crack free. Both the systems exhibited competent seismic parameters, thus enhancing confidence to accept and emulate developed precast structural wall systems, owing to their several advantages over conventional structural walls.

Thickness and gravity are both the significant problems and challenges for origami structures in the field of building construction. This paper described a numerical folding analysis method to investigate the kinematic characteristics of thick origami using movable frame structural models driven by the external forces. The numeric methodology of the folding analysis is based on the generalized inverse theory. Therefore, both the morphing modes and the folding paths can be obtained in the environment of gravity through introducing the nodal forces directly. A general modeling approach is proposed to establish thick origami models using kinematic frames. To demonstrate the proposed method, single-DOF and multi-DOF examples are investigated. The folding procedures are obtained under the external forces, and the rigid motion modes are discussed. The presented method shows feasibility of analyzing the folding process of thick origami, which can help assess the practical rapid construction tasks in the future.