Low-cost Construction Research Articles

Probabilistic evaluation of spectral acceleration demands on light secondary systems supported by partially self-centering structures

Partially self-centering structures are promising seismic resilient structural systems by reducing residual inter-story drifts with low initial construction costs. Comprehensive studies focused on structural design and performance evaluation, but no research was conducted to investigate the design of nonstructural components in partially self-centering structures. This research focuses on developing the probabilistic spectral acceleration demands for the nonstructural design in partial self-centering structures. 320 near-fault recorded ground motions were adopted for considering the uncertainties of seismic excitations. The spectral accelerations of the light nonstructural component were obtained through comprehensive dynamic analyses. The logarithmic normal distribution can be used for describing the probabilistic distribution of floor spectra for partially self-centering structures under earthquakes, validating through the Anderson-Darling test. The influences of design parameters (including structural period, hysteretic parameters, structural damping, the ratio of the structural period to the nonstructural period, and nonstructural damping) on the probabilistic distribution of floor spectra were investigated through parametric dynamic analysis results. Artificial neural network (ANN) models were developed for predicting the probabilistic floor spectra for partially self-centering structures. The analysis results indicate that ANN models can achieve excellent accuracy with a coefficient of determination larger than 0.99. Comparative analysis results reveal that the ASCE method may underestimate the acceleration demand of light secondary systems supported by partially self-centering structures. The developed ANN models were interpreted using the shapely additive explanations. It has been found that the fundamental periods of the main structure and nonstructural components and the response modification factor show significant effects on the median and deviation of the probabilistic floor spectra for partially self-centering structures. The software FloorSpecPS was established to predict the probabilistic floor spectra for partially self-centering structures using the developed ANN models in practical application.

Barriers and Enablers for Green Concrete Adoption: A Scientometric Aided Literature Review Approach

Green concrete is a concept of concrete that uses waste materials to reduce its environmental impact and has various benefits for the environment, economy, and society, such as lower construction cost, less landfill waste, new waste markets, and better quality of life. This study aims to investigate and analyze the barriers and enablers for green concrete development and implementation, based on a mixed-method approach that combines a scientometric analysis and a literature review. The Scopus database was explored first and then these data were used to investigate and capture six categories of barriers and enablers: awareness, technical, economic and market, implementation, support/promotion, and social. Results reveal that the technical and operational aspects are the main challenges for green concrete, while the awareness and social acceptance are not major issues. The current study surpasses the mere popularization of green concrete. Instead, it delves into its multifaceted dimensions, that is, technical, economic, social, and institutional. By meticulously analyzing a diverse group of research articles, key challenges and opportunities associated with green concrete are pinpointed. The findings not only deepen our understanding of the barriers impeding the widespread adoption of green concrete, but also shed light on potential solutions. In summary, this work bridges theory and practice, providing invaluable insights for future researchers, practitioners, and policymakers in the sustainable construction domain.

Performance-based assessment of the novel prefabricated CFST bridge pier by numerical approach

This study aims to profoundly investigate the seismic performance and application prospect of the typical continuous beam bridge with the novel prefabricated concrete-filled steel tubular (CFST) piers, with advantages in simple on-site assembly, convenient transportation of prefabricated components, good seismic performance, and low construction cost. According to two prototype continuous beam bridges respectively equipped with low and tall typical reinforced concrete (RC) piers, 7 bridge cases with prefabricated CFST piers featuring various configurations of the tie beams are designed. Three-dimensional numerical models of these bridge cases are established and verified with the previous experimental studies, and numerical simulations of all the bridge cases are conducted to assess and compare the seismic responses and fragility curves. The results show that the bridges with prefabricated CFST piers exhibit a reduction in top pier transversal displacement and maximum curvature along the pier height, which are 43 % and 138 % lower than those of the prototype RC piers, respectively. Besides, the bridges with prefabricated CFST piers generally present lower probabilities of being damaged compared to those of the prototype bridges with RC piers.

Differentiation of aging properties in different circumferential layers of the polyethylene pipeline

Abstract Polyethylene (PE) pipelines have been widely used as a substitute for steel pipelines in urban natural gas transportation around the world, due to their corrosion resistance, low cost, and good construction performance. As a kind of non-metallic material, PE pipelines age while being used. Currently, the aging status of PE pipelines is not clear and a reliable method to evaluate the aging life of them is necessary to be deeply explored. Due to the different contact with oxygen while using, the aging conditions of the outer, middle, and inner layers are also various. According to the research in this work, the aged PE80 pipelines in accelerated aging experiments were divided into three layers including outer, middle, and inner layers. The aging performance of the three layers has great differences. A comprehensive method for the aging properties of PE80 pipelines should be established while evaluating PE pipelines in service.

ДОСВІД ЕКСПЛУАТАЦІЇ ТА ОСОБЛИВОСТІ РОБОТИ ВОДОПРОПУСКНИХ СПОРУД ІЗ МЕТАЛЕВИХ ГОФРОВАНИХ КОНСТРУКЦІЙ НА АВТОМОБІЛЬНИХ ДОРОГАХ

Introduction. Road culverts made of metal corrugated structures despite of more than a hundred years of application history, in Ukraine they are a fairly new type of construction and are widely used in transport construction as an alternative to traditional steel or concrete bridge structures. The well-known advantages that justify the choice of such a solution are mainly a short term and relatively low cost of construction, construction provided that the appropriate technological regime is followed and does not cause any particular problems. However, the modern process of design and construction of road culverts from metal corrugated structures is imperfect and is constantly being improved. Therefore, there is a need to conduct an analysis conditions of operation and features of the operation of road culverts from the metal corrugated structures with the determination of approaches to improving design and construction to further increase the durability of the structure as a whole. Problems. From the literature analysis, it was established that road culverts are in difficult operating conditions, which causes their premature destruction. Goal. It consists in the analysis of operating experience and features of the operation of culverts made of metal corrugated structures on highways with the installation of measures to increase durability.

Design, Simulation and Optimization of a Novel Transpired Tubular Solar Air Heater

In this paper, a novel tubular solar air heater is introduced. In this air heater, the hot boundary layer is drawn into the absorber tube and can provide thermal energy at moderate temperatures. Several different cases were simulated and a correlation was proposed to predict the collector’s effectiveness as a function Rayleigh number and Reynolds number. An equation was derived to find the effectiveness of this collector. Finally, a real case was studied with non-uniform solar flux distribution, as well as radiation heat loss. Good agreement was found between the results and those derived by the proposed analytical method. For different suction values, the first-law and the second-law efficiencies were calculated. Based on the exergy analysis, exergy destruction in absorption is the dominant factor that is unavoidable in low-temperature collectors. It was shown that there is an optimum suction value at which the second-law efficiency is maximized. At the optimum point, temperature rise can reach 54 K, which is hardly possible with a flat plate collector. Based on the exergy analysis, the relation between tube wall temperature and air outlet temperature in their dimensionless forms at the optimum working condition was derived, and it was shown that effectiveness at the optimum working condition is around 0.5. This means that the air temperature rise shall be half of the temperature difference between collector wall and the ambient temperatures. A high outlet temperature besides the low cost of construction and maintenance are the main advantages of this air heater. With such a high temperature rise, this type of collector can increase the use of solar energy in domestic applications.

Experimental Test Bench In A Wave Flume For The Development Of A New Mini Morphable Wells Turbine

The aim of this research study is to perform experimental tests on a new morphable mini Wells turbine designed to operate in presence of waves with limited energy content which presents a high frequency of occurrence along the Mediterranean coasts (Corsini et al., 2010). The strengths of these mini Wells turbines are: i) extremely light rotor; ii) no need of actuators to morph the rotor blades; iii) low construction and maintenance costs; iv) capability to produce energy starting from low wave heights in the order of a few decimetres. Furthermore, the small size and low investment costs of the turbine make it particularly suitable to be installed either in existing structures, such as anti-reflective perforated caissons (often used in the Mediterranean harbors), or in devices for coastal defense from erosive phenomena located on shallow water conditions. The need to carry out experimental tests derives from the difficulty of handling in a virtual Computational Fluid Dynamics environment the huge difference in the time scale of the turbine, which spins at 1500-3000 rpm, and the wave periods, in the order of some seconds (Corsini et al., 2012; Barnabei et al., 2020). Properly designed lab tests, executed in controlled conditions with irregular sea states, are therefore mandatory to fully characterize the behavior of morphable Wells turbines to be employed in the Mediterranean Sea, and in particular to assess their self-start capability.

INDUSTRY PERSPECTIVE ON THE TRANSITION TO ECO-FRIENDLY SINGLE-FAMILY HOMES

As the global climate continues to change, countries across the world face a critical challenge in balancing sustainable construction, lowering construction costs, and increasing housing affordability and the United States is no exception. Since the U.S. building sector is a major contributor to CO2 and other greenhouse gases emissions, it necessitates the adoption of eco-friendly construction practices, which may increase construction costs. On the other hand, with the persistent yet increasing demand for affordable housing, it is imperative to navigate these concurrent issues efficiently. The challenges of climate-friendly buildings, affordable construction, and housing costs come together in a complex way. Ensuring that housing is both environmentally friendly and affordable for everyone, a deep understanding and innovative ideas are essential. The overarching goal of this study is two-fold. First, it aims to understand how the building industry in the state of Massachusetts, U.S. is addressing the transition to building more eco-friendly single-family homes. Second, it looks at the construction costs associated with building these energy-efficient homes by obtaining real estimates from subcontractors. Through these steps, this study offers a clear picture of the challenges and opportunities in an effort to provide housing that is both energy-efficient and affordable.

INDUSTRY PERSPECTIVE ON THE TRANSITION TO ECO-FRIENDLY SINGLE-FAMILY HOMES

As the global climate continues to change, countries across the world face a critical challenge in balancing sustainable construction, lowering construction costs, and increasing housing affordability and the United States is no exception. Since the U.S. building sector is a major contributor to CO2 and other greenhouse gases emissions, it necessitates the adoption of eco-friendly construction practices, which may increase construction costs. On the other hand, with the persistent yet increasing demand for affordable housing, it is imperative to navigate these concurrent issues efficiently. The challenges of climate-friendly buildings, affordable construction, and housing costs come together in a complex way. Ensuring that housing is both environmentally friendly and affordable for everyone, a deep understanding and innovative ideas are essential. The overarching goal of this study is two-fold. First, it aims to understand how the building industry in the state of Massachusetts, U.S. is addressing the transition to building more eco-friendly single-family homes. Second, it looks at the construction costs associated with building these energy-efficient homes by obtaining real estimates from subcontractors. Through these steps, this study offers a clear picture of the challenges and opportunities in an effort to provide housing that is both energy-efficient and affordable.

Laser-assisted synthesis of MnOx and 3D graphene composites for wide-voltage flexible planar microcapacitors

Herein, we propose a simple and eco-friendly strategy based on laser direct writing technology to regulate the valence state of Mn-based oxides nanoparticles anchored on three-dimensional(3D) framework of laser-induced graphene (LIG) for the application of high-performance flexible planar interdigital microsupercapacitors (MSCs). Under the laser radiation, a polyimide (PI) and MnO2 composite film was directly converted into 3D graphene and MnOx (MnO, MnO2 and Mn3O4 mixture). Furthermore, the results reveal that LIG/MnOx MSCs device exhibits a high specific capacitance of 23.3 mF cm−2, which is about 29 times higher than that of LIG MSCs (0.8 mF cm−2). Moreover, LIG/MnOx MSCs possess a high energy density of 7.28 μWh cm−2, outstanding cycle stability with the capacitance retention rate of 97.4 % after 10,000 cycles, and excellent mechanical flexibility. Therefore, this preparation strategy of LIG/MnOx provides a reference for the performance regulation of Mn-based oxides and the low-cost construction of MSCs devices with high energy density, which carries significant research implications for diverse flexible wearable electronic applications in the forthcoming days.

Optimizing urban green infrastructure using a highly detailed surface modeling approach

Urban trees and forests show a better ecosystem with many benefits, including pure air quality. The development of urban green infrastructure (UGI) creates a better management system that greatly impacts social values in an urban system. The UGI and construction activities are receiving much attention for their effectiveness in addressing various urban ecological, social and economic issues. Using green infrastructure in stormwater management can reduce the influence on urban sewerage systems and, eventually, on building water resources. The main goal of the research is to optimize the green infrastructure to provide a less-pollution, well-organized, and pleasurable environment for the inhabitants. Various models are used to study the present rainfall-runoff scenario, but the stormwater management model (SWMM) is the most preferable and suggested model. Once the parameters are accessed, optimizing the green infrastructure (GI) will be easy. A complete SWMM model is evaluated over the complete surface, and a hydrological measurement is presented. The evaluation study presents various component percentages: asphalt (37%), green (27%), ceiling (21%), grit (12%), and cemented area (2%), which provides rainproof coverage of approximately 60%. A design is developed about the diverse events of GI in urban exploiting the SWMM and demonstrates its stimulus on the rainfall-runoff behaviour. In recent years, very little attention has been given to green spaces in urban areas, which not only increases pollution but also decreases the urbanization. Therefore, urban green spaces are more important to improve air quality and resident living standards. Over the given scenario and the rainfall event, a decline of the quantitative discharge parameters is evident, such as discharge volume (i.e., from 3.6 to 61.8) and the peak discharge rate (i.e., from 5.4 to 62.7%). The simulation results show that green areas give high satisfaction with low construction costs, which shows the superlative performance ratio of the examined measures. From the investigation, it is also recommended to have green areas and public spaces in impervious urban areas, which greatly reduced the runoff in the project area.

In Situ Loading of Ni3ZnC0.7 Nanoparticles with Carbon Nanotubes to 3D Melamine Sponge Derived Hollow Carbon Skeleton toward Superior Microwave Absorption and Thermal Resistance.

The simple and low-cost construction of a 3D network structure is an ideal way to prepare high-performance electromagnetic wave (EMW) absorption materials. Herein, a series of carbon skeleton/carbon nanotubes/Ni3ZnC0.7 composites (CS/CNTs/Ni3ZnC0.7) are successfully prepared by in situ growth of Ni3ZnC0.7 and CNTs on 3D melamine sponge carbon. With the increase ofprecursor, Ni3ZnC0.7 nanoparticles nucleate and catalyze the generation of CNTs on the surface of the carbon skeleton. The minimum reflection loss (RL) value of the S60min composite (loading time of 60 min) reaches -86.6dB at 1.6mm and effective absorption bandwidth (EAB, RL≤-10dB) is up to 9.3GHz (8.7-18GHz). The 3D network sponge carbon with layered micro/nanostructure and hollow skeleton promotes multiple reflection and absorption mechanisms of incident EMW. The N-doping and defects can be equivalent to an electric dipole, providing dipole polarization to increase dielectric relaxation. The uniform Ni3ZnC0.7 nanoparticles and CNTs play a key role in dissipating electromagnetic energy, blocking heat transfer, and enhancing the mechanical properties of the skeleton. Fortunately, the composite displays a quite low thermal conductivity of 0.09075Wm·K-1 and good flexibility, which can provide insulation and quickly recover to its original state after being stressed.

Cost Benefits of Net Zero Energy Homes in Australia

This paper presents a systematic analysis of energy savings and cost benefits associated with several options for integrating energy efficiency and renewable energy technologies. The primary goal of this study is to assess the cost-effectiveness of achieving optimal net-zero energy (NZE) designs for residential buildings in Australia. Specifically, the analysis combines a series of sensitivity analyses and multi-objective optimizations to account for a wide range of design strategies for detached homes in four cities representing different Australian climates. The results indicate that not only are NZE designs technically feasible for all the considered Australian cities, but they are also highly cost-effective. This cost-effectiveness is attributed to the lower installation costs of rooftop PV systems as well as the beneficial interactive effects of proven energy efficiency strategies. Indeed, it is found that the deployment costs of rooftop PV systems can be recovered in less than 4 years. Moreover, the addition of thermal insulation in walls and ceilings can reduce both HVAC capacities and annual energy end-use by up to 59%. Based on an optimization-based design, NZE homes in Australia can have lower construction costs and, ultimately, lower life cycle costs than dwellings built to meet current energy efficiency standards based primarily on stringent building envelope thermal performance.

Joint beam power and pointing management in multi‐beam low earth orbit and low earth orbit co‐existing satellite system

SummaryRecently, the low earth orbit (LEO) satellite has attracted much attention due to its advantages of low latency and construction costs. However, the scarcity of frequency spectrum resources has resulted in these satellites sharing the same spectrum to provide services for ground users. So, challenges such as overlapping beam coverage and inter‐beam interference occur in the multi‐beam LEO satellite coexistence scenario. Therefore, this paper focuses on the issue of interference coexistence in LEO and LEO (LEO–LEO) co‐existing scenario, where the initially established system is the primary system, and the later established system is the secondary system. The interference coexistence problem is modeled as a multi‐objective optimization problem. The joint beam power and pointing management (JBPPM) based on particle swarm optimization (PSO) is proposed. The power control is applied to the LEO satellites in the secondary system to reduce the interference to the primary system user. Meanwhile, beam pointing optimization is adopted by the LEO users in the secondary system to avoid interference from the primary system and ensure the minimum communication ability. The simulation results verify that the proposed technique can adapt to various coexistence conditions and outperform the existing method.

Cradle to grave: the importance of the fuel cycle to molten salt reactor sustainability

Advanced reactor technologies are being considered for the next-generation of nuclear power plants. These plants are designed to have a smaller footprint, run more efficiently at higher temperatures, have the flexibility to meet specific power or heating needs, and have lower construction costs. This paper offers a perspective on molten salt reactors, promoted as having a flexible fuel cycle and close-to-ambient pressure operation. A complexity introduced by reducing the reactor footprint is that it may require low-enriched fuel for efficient operation, available from enrichment of the feed salt or by reusing actinides from existing used nuclear fuel (UNF). Recycling UNF has the potential to reduce high-level waste, if done correctly. Release limits from UNF processing are stringent, and processes for waste reduction, fission gas trapping, and stable waste-form generation are not yet ready for commercial deployment. These complex processes are expensive to develop and troubleshoot because the feed is highly radioactive. Thus, fuel production and supply chain development must keep abreast of reactor technology development. Another aspect of reactor sustainability is the non-fuel waste streams that will be generated during operation and decommissioning. Some molten salt reactor designs are projected to have much shorter operational lifetimes than light-water reactors: less than a decade. A goal of the reactor sustainability effort is to divert these materials from a high-level waste repository. However, processing of reactor components should only be undertaken if it reduces waste. Economic and environmental aspects of sustainability are also important, but are not included in this perspective.

DESIGN OF QUICK-ASSEMBLY MODULAR BUILDINGS FOR THE NEEDS OF UKRAINIAN DISPLACED PERSONS

Problem statement. From time to time, natural or man-made disasters (floods, fires) occur in various parts of the world, during which residential and infrastructure objects are completely or partially destroyed. Due to the destruction of houses, detached or multi-storey, as a result of hostilities, people are forced to leave their destroyed buildings and look for temporary accommodation. Unfortunately, due to the open military aggression of the Russian Federation that began in February 2014 on the territory of the Republic of Crimea and the Donetsk and Luhansk regions and the second, more intensive phase of military operations from February 2022 on the territory of ten regions of Ukraine (Donetsk, Luhansk, Zaporizhzhia, Kherson, Mykolaiv, Kharkiv, Sumy, Chernihiv, Zhytomyr, Kyiv regions). In the territory of the specified regions, during the hostilities, the housing stock of some cities and villages suffered significant destruction (Mariupol, Irpin, Gostomel, Bucha), in addition, there are a large number of families who are forced migrants fleeing from the temporarily occupied territories. At present, it is important to design a separate residential modular building from the available building materials on the Ukrainian market and in accordance with current building, climatological and sanitary norms of Ukraine. The aim of this work is to design an economical autonomous modular building from publicly available building materials, which will meet state building standards for reliability, energy efficiency and sanitation. Conclusions. A modular building has been designed that meets all the necessary modern reliability criteria. Local public building materials are used for the construction of the building, which significantly reduces the total cost. The construction of the house is made in factory conditions, and the erection is carried out on site within 2 days. The building is designed to be collapsible, which allows it to be moved for repeated use. The cost of a modular house is UAH 146,808. (as of May 2022). The low cost of construction is relevant in the period of weakening of the economic capacities of the state.

Evidence of combined flower thermal and drought vulnerabilities portends reproductive failure under hotter-drought conditions.

Despite the abundant evidence of impairments to plant performance and survival under hotter-drought conditions, little is known about the vulnerability of reproductive organs to climate extremes. Here, by conducting a comparative analysis between flowers and leaves, we investigated how variations in key morphophysiological traits related to carbon and water economics can explain the differential vulnerabilities to heat and drought among these functionally diverse organs. Due to their lower construction costs, despite having a higher water storage capacity, flowers were more prone to turgor loss (higher turgor loss point; ΨTLP) than leaves, thus evidencing a trade-off between carbon investment and drought tolerance in reproductive organs. Importantly, the higher ΨTLP of flowers also resulted in narrow turgor safety margins (TSM). Moreover, compared to leaves, the cuticle of flowers had an overall higher thermal vulnerability, which also resulted in low leakage safety margins (LSM). As a result, the combination of low TSMs and LSMs may have negative impacts on reproduction success since they strongly influenced the time to turgor loss under simulated hotter-drought conditions. Overall, our results improve the knowledge of unexplored aspects of flower structure and function and highlight likely threats to successful plant reproduction in a warmer and drier world.

Open pit limit optimization considering the pumped storage benefit after mine closure: a case study

Repurposing a closed mine as lower reservoir is a cost-effective way for the construction of pumped storage hydropower (PSH) plant. This method can eliminate the expenses of mine reclamation, reservoir construction, and land acquisition, resulting in significant cost savings and benefits for the PSH project, known as the PSH benefit. The construction of PSH plants within a closed mine is divided into surface mode and semi-underground mode in this paper. Through a general comparison of two in-situ cases, the finding highlight that the surface mode can achieve a larger potential installed capacity and lower construction cost. Furthermore, the PSH benefit is quantified and internalized as an economic parameter in the ultimate pit limit (UPL) optimization by allocating it into unit ore. Taken an undisclosed open-pit iron mine as example, the UPL is optimized by considering the PSH benefit. The internalized PSH benefit is calculated to be 6.59 CN¥/t when the installed capacity is 2000 MW, and ore amount within the optimized UPL is increased by 1.4%. The results indicated that the PSH benefit does influence the shape and size of UPL, but not significantly. Besides, converting several bottoms in a single open-pit into lower and upper reservoirs presents more challenges for UPL optimization, which further explorations is needed.

Low-cost experiments for teaching eletrostatics in Brazilian high school

Many public schools in Brazil do not have the financial resources to obtain certain equipment for teaching physics. Considering that the Brazilian National Common Curricular Base, a normative document that defines the organic and progressive set of essential learning that all students must develop, determines that the curriculum for teaching electromagnetism for high school encompass electrostatics. It is very important that schools offer laboratory conditions. For this reason, it was proposed to design simple and low-cost construction equipment, so that teachers from the basic education network can build them for their schools, thus improving the quality of teaching for their students. This study aims to gather equipment and experiments, such as electroscope, electrophorus, Leyden jar and Van de Graaf generator, which can be used in the classroom for didactic purposes in physics teaching. The main focus of this work is the construction of equipment for the implementation of a laboratory for the study of electrostatics, which addresses physical concepts seen by high school students of the basic network in Brazil.

Enhancing data quality and real-time sharing performance in water informatics through decision tree mining algorithm

The project of water conservation is crucial to the current social development since it continuously aids in human adaptation, utilization, transformation, and protection of the water environment, which is used to meet development needs. Urbanization has led to a rise in the need for water conservation projects as well as a rise in the need for real-time information, which is necessary to find pertinent engineering information during construction and prevent repeat investments in the project, thus lowering construction costs. Owing to the low quality of the mining dataset utilized in the conventional sharing system, which hinders real-time sharing and system scalability, the decision tree mining algorithm was used to design the water conservation informatization data sharing system. The decision tree mining technique is utilized to mine the data associated with water conservation informatization, create a model for data sharing, and create a transmission format for data sharing in order to accomplish data sharing. According to the experimental results, the designed system's accurate rate is 4.3% and 6.12% greater than that of the two conventional systems. Furthermore, the system's design offers improved real-time performance, scalable data exchange, and superior quality of data.