Full-scale Construction Research Articles

Quantification of hydraulic characteristics and validation of CFD simulation of subsurface flow constructed wetlands using tracer

The analysis of residence time distributions (RTDs) is of great significance in the hydraulic characterization of subsurface flow constructed wetlands (SSF-CWs), and tracer experiments and simulations are generally used methods to obtain RTDs. This study developed a computational fluid dynamics (CFD) model involving two tracer tracking approaches in order to understand and quantify the flow behavior in SSF-CW. To validate the CFD model, RTDs were obtained from bench-scale impulse response tests with finite-constant injection of tracer, and the hydraulic indexes were corrected by introducing tracer injection time and nominal residence time in the formulae. The shape similarities of RTDs between the CFD model, the gamma model and observation were evaluated by a dynamic time warping algorithm, where the CFD model incorporating advection, diffusion and dispersion processes had the highest shape similarity (0.94–0.98). The proposed CFD model gave the tracer the same velocity field as the fluid, characterizing more accurate hydraulic indexes compared to the gamma model. The CFD model is appropriate for design optimization prior to full-scale construction since it saves time and is environmentally benign. It also gives visualization of the tracer trajectory, which aids in understanding contaminant fate and transport within the SSF-CW.

Do nothing, do minimum or do something? Why public project appraisals “always” recommend large projects

PurposeIn the project initiation phase, an appraisal is needed to clarify the strategic problem and alternative solutions. Full-scale construction projects and simple solutions (do-minimum alternatives) should be assessed. The do-nothing alternative is the baseline for the appraisal and an option in itself. The paper explores the role of do-nothing and do-minimum alternatives in public project appraisal, which may significantly impact the attractiveness of a construction project.Design/methodology/approachThe paper presents an empirical study from Norway, which requires external quality assurance (QA) of early project appraisals. The data include an extensive document review of 112 projects and interviews with 41 experts involved in the appraisal processes.FindingsOf 112 appraisals, 110 recommended a major construction project, including cases where the benefits and value were low or uncertain. The do-nothing alternative was generally included as a reference but not treated as a viable option. Do-minimum alternatives were often not explored. By contrast, the external QA reports recommended do-nothing or do-minimum in 28 cases. Interestingly, although political decision-makers rarely reject projects, they may put them on hold indefinitely, implying that the actual outcome in many cases is still do-nothing.Originality/valueThe paper addresses a topic that has been understudied in the literature. The findings contribute to the broader literature on project initiation processes, project appraisal and how to reduce the risk of bias and manipulation in appraisals.

5G in construction: from deployment to evaluation for robotic applications

AbstractA stable, low-latency, and high-bandwidth communication infrastructure is indispensable for effective teleoperation or automated control of construction machinery. Despite the vital importance of this aspect, limited exploration has been undertaken thus far. Our work presents a comprehensive study that begins by detailing the strategic deployment of a 5G network, underscoring its tailored features and functionalities designed specifically to meet the demanding requirements of construction sites. Through a series of diverse experiments involving different types of full-scale construction machines, we vividly demonstrate the tangible benefits of 5G technology in this context. Leveraging comparative studies with WiFi technology and real-world tests, this methodology highlights the improvements in communication facilitated by 5G networks. This holistic exploration not only fills a critical gap in understanding the potential of 5G in construction machinery communication but also offers a roadmap for leveraging this technology to further develop the construction industry.

Mechanistic investigation of grid-reinforced asphalt pavements with measured interface properties

The bond properties at layer interfaces are a required input in mechanistic asphalt pavement models. For design and analysis procedures, involving the calculation of key responses that are commonly linked to performance, perfect bond conditions are regularly assumed between layers. One emerging approach for prolonging the service life of asphalt pavements, either new or rehabilitated, is installing asphalt grid reinforcement (AGR) products between paving lifts. In these cases, the perfect bond assumption may not hold – undermining the reinforcement potential. Accordingly, the objective of this study was to investigate the effects of layer interface properties on key responses in pavements with AGR. The investigation was carried out by combining results from a full-scale construction, laboratory tests on asphalt concrete (AC) cores, and synthetic simulations. The latter were performed with a recently developed semi-analytic mechanistic code that can accept AGR products. This code can handle time- and temperature-dependent layer and interface properties, as well as moving loads. From the laboratory tests, it was found that the bond between AC lifts, with and without an AGR, is time- and temperature-dependent – best characterised by a relaxation interface stiffness function. This relaxation function was measured to be consistently larger without an AGR than with an AGR. Nonetheless, pavement simulations showed that including an AGR has no pronounced effect on strain magnitudes under high-speed/low-temperature conditions, can lessen horizontal strain magnitudes at the reinforced interface and at the AC bottom (mainly under slow-speed/high-temperature conditions, and depending on the installation depth of the AGR), and has no pronounced effect on deflections regardless of the loading speed and temperature level. It is concluded that even if laboratory measurements display a reduced interface stiffness when including an AGR, the reduction may not have any practical implication on key pavement responses, and the reinforcement potential is not necessarily undermined. The modelling and experimental approaches outlined and utilised in this study offer a rational tool for analysing this matter/question on a case-by-case basis.

Research on the Cooperative Development Mode of Rural Tourism Resorts — Taking Huangpu River Source Tourism Resort as an Example

The Huangpu River Source Tourism Resort, situated within Anji County, Zhejiang Province, encompasses the administrative boundaries of Baofu Town, Zhangcun Town, and Hanggai Town. With the establishment of the resort's management committee, upper-level planning and coordination have gradually fallen into place, facilitating the full-scale construction of the resort. As a rural-oriented tourism destination aimed at fostering comprehensive development across these three townships, disparities are anticipated in terms of development foundations, tourism competitiveness, and development approaches. The purpose of this paper is to establish an evaluation index system for rural tourism competitiveness within the region. Utilizing factor analysis via the SPSS tool, it seeks to assess the strengths and weaknesses of each town's development factors, thereby evaluating the tourism development foundation and potential across the three towns. This endeavor aims to provide more effective guidance for the scientific construction and management of the Huangpu River Source Tourism Resort in Anji County and to explore a linked development model for the resort.

Investigation into Power Line Supporting Structure Dynamic Properties by Means of Impulse Test

Dynamic analysis of a large, full-scale construction requires proper excitation in order to induce vibrations that can be measured and further processed. The amount of delivered energy over the frequency band must be sufficient to excite all the mode shapes in the studied range. The paper concerns the pseudo-impulse pull-and-release method that allows to determine frequency response functions of a large, lightly damped structure and estimate its modal parameters. The main advantage of the developed method is the great independence of the repetitiveness of the experiment’s operational parameters. The output time histories from subsequent partial experiments are accurately synchronised and normalised without measuring the signal of input excitation. The research conducted for the full-scale transmission tower results in modal parameters, estimated by classical and pseudo-impulse methods. The applied pseudo-impulse improves the conditioning of the excitation and results in the better readability of stabilisation diagrams as well as in a better stabilisation of the poles that are not clearly represented in the input data. The proposed method allows for the visualisation of poles which are non-detectable in cases of classical analysis.

Comparison of Relative Structural Characterization Methods for Additive-Modified Asphalt Mixtures

The evaluation, adoption, and efficient deployment of asphalt additives in flexible pavements has historically been a relatively slow process, requiring years of testing and evaluation before a new product may be fully and readily used in pavement cross-sections. However, the fast-paced and innovative nature of the additive marketplace produces numerous products that have the potential to improve performance, reduce costs, or both, but have been hindered by slow deployment. To address the need for a more rapid set of evaluation tools, the National Center for Asphalt Technology Test Track initiated an Additive Group experiment in 2021 to build full-scale pavement test sections modified with several asphalt additives, including recycled tire rubber, recycled plastics, reactive polymers, and aramid fibers. Data will be collected from these test sections to develop a framework for evaluating asphalt additives in the future. Phase 1 of the investigation was to conduct limited laboratory testing and structural analysis from which a group of additives would be selected for full-scale construction and evaluation. Focused on fatigue cracking, this paper details the laboratory testing conducted for Phase 1 and two different structural pavement analysis methods using FlexPAVE™ and WESLEA. Even though the two structural pavement analysis methods are very different, the FlexPAVE and WESLEA analyses provided strongly correlated predicted cracking performance, remarkably similar predictions of equivalent pavement thicknesses, and nearly identical structural layer coefficients. It is recommended that these two approaches be further evaluated against laboratory and field performance data that will be collected from the Additive Group experiment.

Technical analysis of full-scale Construction and Demolition Waste treatment plants: case studies of the Lombardy Region, Italy

Construction and demolition activities in Italy and the Lombardy Region produce a considerable amount of wastes that can be valorised as secondary raw materials. The recovery of construction and demolition wastes is severely limited by the lack of consolidated and sustainable treatment chains and by the strong variability of their environmental characteristics that may generate potentially dangerous effects for the environment. The purpose of this study was to evaluate and technically define the current treatment chains in the Province of Brescia (Lombardy) by analyzing three full-scale treatment plants in order to highlight barriers to demolition waste recovery and propose possible solutions and improvement strategies. To best represent the entire management and treatment system, the analysis was developed on all the acceptance, treatment, and final quality control phases. Moreover, chemical composition and leaching data on demolition wastes and recycled aggregates were collected from the three treatment plants and statistically analyzed to assess their potential recovery according to the Italian legislation. Mixed non-hazardous waste is the fraction mostly managed by recycling plants and mixed recycled aggregates are the main products obtained from the treatment. These are mostly used in roads and in geotechnical applications. Chemical composition results showed that the pH is generally alkaline and tin and benzene are the most critical elements for both demolition wastes and recycled aggregates with respect to the regulatory limit values. Total chromium was identified as a critical compound in leachates. The results of the statistical analysis confirmed that chromium was mainly released by cement materials.

Advantages of Contour Crafting in Construction Applications

Contour crafting application has been widely used in different industrial, pharmaceutical, medical, and aviation applications for more than three decades. Recently, mega-sized 3-D printers were developed, with sufficient capability to print full-scale construction projects, including walls, homes, bridges, and multi-story buildings. Successful 3-D printing of projects is accomplished by the Additive Manufacturing (AM) process through the placement of successive layers of construction materials using robotic arms (3-D printers). This layered construction, known as contour crafting, is controlled by computer modeling software. This paper presents the history of contour crafting development, its current application in construction, the advantages of contour crafting applications in construction, and the main impediments to the widespread of contour crafting in the local construction market. In addition, this paper highlights the current research efforts made to integrate Building Information Modeling (BIM) in contour crafting construction. Based on the recent research findings, contour crafting application in construction improves job site productivity and project sustainability as a result of reduced material waste in construction sites. Finally, the automated construction through the application of contour crafting technique results in improved job site safety and increased overall quality of construction projects due to the increased automation in construction.

Construction of an Electrically Heated Asphalt Road Based on Ribbon Technology

Although asphalt pavements are the most common pavement type worldwide, there is no accepted heating solution for this infrastructure class for melting snow and preventing ice formation at the ride-surface. This study was concerned with utilizing electric ribbon technology as a suitable heating solution. A method was proposed to introduce ribbon heaters into the typical paving process in a practical manner, causing minimal disruption to the normal paving operations, that is potentially expandable to large areas. The advocated idea was to deploy ribbons after an asphalt concrete (AC) lift has been paved and compacted, and before paving and compacting the next AC lift(s). In this context, a special grooving machine was envisioned to make shallow channels in the AC for cradling each ribbon. Thus, the system survivability is guaranteed, with all ribbons protected against the maneuvering of trucks, paving equipment, and heavy rollers. Subsequently, the method was demonstrated through the full-scale construction of a heated road that included installing ribbons in-between AC lifts. For this purpose, the protective ribbon channels were grooved with a customized milling machine. The entire construction process was described in detail, and some initial findings from activating the system were also included. An overall system survivability of 97% was achieved, and the installation concept appears practical and up-scalable.

Features of Thermal Nondestructive Testing of Impact Damage to Products Made of Polymer Composite Materials

Abstract—The widespread introduction of polymer composite materials (PCMs) into aviation technology has led to the search and selection of effective methods for nondestructive testing of aircraft structure elements. According to the operating data, one of the main types of accidental damage to aviation equipment is shock effects. Therefore, the problems of detecting such damage to PCM products using thermal nondestructive testing as a promising method and identifying the features of this approach are relevant. In this work, the authors carried out tests on standard samples of materials, structurally similar samples, and the elements of a full-scale aircraft construction. The results of thermal imaging surveys of impact damage to PCM products were analyzed with standard and dedicated software after testing. Suggestions recommended for further research and practical use are formulated.

The Hornet's Nest pavilion - learning the challenges of full-scale construction from a digital model

In 2018, BuroHappold Engineering and Studio X of the Hochschule Anhalt Graduate School of Architecture in Dessau, Germany, collaborated on the design and construction of the Hornet's Nest, a parametrically designed, temporary, timber pavilion assembled without the use of mechanical connections. The collaboration was part of the graduate school’s approach to teaching design, combining virtual three-dimensional (3D) modelling with full-scale building projects to foster understanding of the challenges of full-scale construction from a digitally designed model.

Chinese High-speed Railway: Efficiency Comparison and the Future

High-speed railway (HSR) network building was initiated in China in the early 2000s, and full-scale construction began several years later as a larger use phase started in 2008. Thereafter, the expansion speed has been impressive. Network investment could be considered as a success, if evaluating the amount of high-speed railway usage already during the expansion phase. The diffusion models built in this research show that expansion in the network and growth of the passengers will continue at least until the following decade. The performance is evaluated in terms of DEA efficiency model. It is shown that efficiency started from very low levels, but it has been increasing together with the expansion of HSR network. Currently, the efficiency is near the level of the leading European High-speed (HS) countries (Germany and France). However, it is projected with linear model and by Bass diffusion models that the efficiency will reach Japanese and South Korean standards in the next decade. A somewhat larger network length with smaller relative growth of passengers, but with a higher growth of passenger-km seems to be able to reach even the frontier efficiency.

Full-scale construction and testing of stress-laminated columns made with low-grade wood

Stress lamination is a simple construction technique widely used in timber bridge decks. This study presents a new application of stress lamination for making timber columns. Using prestressing rods and friction forces instead of glue, numerous connections and twenty-five full-scale columns were built with low-grade wood and structurally tested. The results show how stress-laminated columns display comparable buckling performance to solid timber and glulam columns. A six-month testing period with novel connection details further confirms how prestress losses can be reliably controlled. This work highlights the broader potential and performance of stress lamination in modern timber engineering and building design.

RESULTS OF EXPERIMENTAL RESEARCH OF THE REINFORCED CONCRETE SHELL-SLAB

Introducton. The paper demonstrates the results of experimental research of the reinforced concrete shell-slab under the action of vertical uniformly distributed load. The authors also present the comparison of such research results with the results of stress-strain state evaluation performed in the “Lira” software package.Materials and methods. The authors tested the reinforced concrete model representing physically similar copy with the 1:5 scale coefficients by general size, and by separate details. The load was applied in 10–15% doze of the theoretical bearing capacity of the plate.Results. The authors calculated the experimental transverse stress σх,3,exp, which was in full-scale construction and in the 3 central sphere. The authors also made the comparison of such transverse stress with theoretical transverse stresses σх,3,teor and the comparison was performed in the “Lira” program complex. The diagrams of the above stresses were well matched by outlines and values.Discussion and conclusions. As a result, the experimental (σx, 3,exp.) and theoretical (σx,3,theor.) stresses are compressive near the shell-slab center. Its maximum stress values (σx, 3, exp) reach x/b=0,5 at a point with a relative coordinate, and the stress (σx,3,theor.) – x/b ≈ 0,45.The zero voltage values σx,3,exp. reach a quarter of the shelf width, theoretical stress –with x/b ≈ 0,3 mm ratio.Maximum values of experimental and theoretical tensile stresses σx, 3 reach x/b ≈ 0,15 ratio. Therefore, the values are close to each other, and do not exceed the standard concrete tensile resistance Rbt, ser.The practical significance of the study is to obtain experimental evidence of the abandoning possibility of the horizontal transverse reinforcement of the shelf, which would reduce the complexity and cost of the investigated structures production.The prospects conclude in:research of the shell-slab operation at the stage of ultimate equilibrium;research of the shell-slab crack resistance and stiffness at all stages of its operation;research of the shell-slab operation taking into account the fixation in the transverse direction of its longitudinal contour edges along entire length.

Geotechnical characteristics of sensitive Leda clay at Canada test site in Gloucester, Ontario

In 1954, the Canadian Geotechnical Research Site No. 1 was established as a testing and experimentation site for the soft and highly sensitive Leda clays that were deposited within the now-drained Champlain Sea. The Gloucester test site has a shallow groundwater table taken as hydrostatic at 0.8 m and is underlain by a sequence of leached marine sediments that make-up the Leda clays and extend about 22 m below grade. Below that are dense glacial tills and limestone bedrock. Previous research studies at the site have included full-scale construction, monitoring, and instrumentation of shallow foundations, embankments, drilled shafts, and driven pilings. Recently, a series of in-situ tests in 2012 and 2014 included type 1 and 2 piezocone soundings, porewater dissipations, and both conventional downhole tests and continuous-interval shear wave velocity measurements have been undertaken. Selected results obtained from laboratory, in-situ testing, and geophysical tests over the past six decades are presented.

The Enhanced Sealing Project (ESP): 2009–17 monitoring of a full-scale shaft seal installed in granitic rock

Abstract The Enhanced Sealing Project (ESP) is monitoring the thermal–hydraulic–mechanical (THM) responses of a full-scale shaft seal at Canadian Nuclear Laboratories (CNL) former Underground Research Laboratory (URL) site. The evolution of such a full-scale construction has direct relevance to closure design of repository shafts (and tunnels) in a range of host rock types. The shaft seal is installed across a water-bearing fracture (fracture zone (FZ2) at c. 270 m depth), marking the interface between deeper, more saline groundwater and nearer-surface freshwater environments. Intended to demonstrate an ability to install a sealing structure that can limit the movement of water between the two hydrological regimes, the main shaft seal consists of a 40% bentonite clay: 60% fine aggregate by dry mass component ( c. 6 m thickness) sandwiched between two 3 m-thick concrete segments in the approximately 5 m-diameter main shaft. The clay and concrete components provide the primary hydraulic sealing and mechanical constraint to the sealing material, respectively. This paper presents the monitoring results of the ESP from its installation in 2009 through to mid-2017. At present, the seal is still not completely water-saturated, pressures within it are still developing and flooding of the upper shaft is continuing. The ESP provides a comprehensive long-term dataset that will assist in calibrating numerical models describing the performance of placement room/shaft/tunnel seals in a Deep Geological Repository.

Mobile robotic fabrication at 1:1 scale: the In situ Fabricator

This paper presents the concept of an In situ Fabricator, a mobile robot intended for on-site manufacturing, assembly and digital fabrication. We present an overview of a prototype system, its capabilities, and highlight the importance of high-performance control, estimation and planning algorithms for achieving desired construction goals. Next, we detail on two architectural application scenarios: first, building a full-size undulating brick wall, which required a number of repositioning and autonomous localisation manoeuvres. Second, the Mesh Mould concrete process, which shows that an In situ Fabricator in combination with an innovative digital fabrication tool can be used to enable completely novel building technologies. Subsequently, important limitations and disadvantages of our approach are discussed. Based on that, we identify the need for a new type of robotic actuator, which facilitates the design of novel full-scale construction robots. We provide brief insight into the development of this actuator and conclude the paper with an outlook on the next-generation In situ Fabricator, which is currently under development.

The intermediate thermal hydrolysis process: results from pilot testing and techno-economic assessment

Thermal hydrolysis has proven to be an efficient pre-treatment process for sludge before anaerobic digestion (AD), by thermally enhancing organic matter hydrolysis. Recent research has shown that a new configuration with the existing technology can further enhance the efficiency of the system. The intermediate thermal hydrolysis process (ITHP) has been explored and tested in the Sludge and Energy Innovation Centre pilot plant located at Basingstoke sewage treatment works for a period of 15 months. The pilot facility has allowed operational considerations to be explored and understood to inform the design and construction of full scale. ITHP results showed a volatile solids destruction of 64% and an average overall specific gas production of 503 m3/TDS. Furthermore, techno-economic analysis was used to compare conventional thermal hydrolysis process (THP) with surplus activated sludge (SAS) only THP and ITHP. Data captured from operational sites, laboratory scale experiments and the large scale ITHP pilot plant, was used in the model. The results showed that ITHP offers an excellent solution for energy recovery having the best economic return, but overall the largest CapEx. SAS only THP is the cheapest to build but does not perform as well as conventional THP and ITHP. Conventional THP remains an excellent solution when space and AD volume is constrained.

A Teaching Experiment between Design Concept and Structural Behaviour: Full-Scale Constructions in a Second-Year Studio

A Teaching Experiment between Design Concept and Structural Behaviour: Full-Scale Constructions in a Second-Year Studio