Civil Infrastructure Construction Research Articles

STRENGTH DESIGN OF REINFORCED CONCRETE SECTIONS BASED ON A NUMERICAL OPTIMIZATION METHOD

Reinforced concrete structures are widely used in construction of civil infrastructures. Classical methods are available for the analysis and design of reinforced concrete members, such as beams or columns, which are typically done by hand or using a spreadsheet program. In this study, an analysis and design approach of reinforced concrete sections is developed based on a numerical optimization method, and applied in accordance with the latest concrete design code. The basic idea of the proposed approach is to derive an optimization formulation in order to determine the minimum steel area required to support a given factored load combinations applied on a concrete section. A rigorously derived analysis and design framework of general beam sections is presented. For practical applications by civil and structural engineers, the readily-available optimization solver in Microsoft Excel spreadsheet is used. To illustrate the applicability of the approach, a numerical example with different analysis and design cases is studied. The proposed analysis and design approach using numerical optimization and spreadsheet solver works very well and is easy to implement in the Excel environment. The analysis and design results compare well with hand calculation results based on the classical method.

STRENGTH DESIGN OF REINFORCED CONCRETE SECTIONS BASED ON A NUMERICAL OPTIMIZATION METHOD

Reinforced concrete structures are widely used in construction of civil infrastructures. Classical methods are available for the analysis and design of reinforced concrete members, such as beams or columns, which are typically done by hand or using a spreadsheet program. In this study, an analysis and design approach of reinforced concrete sections is developed based on a numerical optimization method, and applied in accordance with the latest concrete design code. The basic idea of the proposed approach is to derive an optimization formulation in order to determine the minimum steel area required to support a given factored load combinations applied on a concrete section. A rigorously derived analysis and design framework of general beam sections is presented. For practical applications by civil and structural engineers, the readily-available optimization solver in Microsoft Excel spreadsheet is used. To illustrate the applicability of the approach, a numerical example with different analysis and design cases is studied. The proposed analysis and design approach using numerical optimization and spreadsheet solver works very well and is easy to implement in the Excel environment. The analysis and design results compare well with hand calculation results based on the classical method.

Limestone calcined clay cement (LC3): A sustainable solution for mitigating environmental impact in the construction sector

The impact of global warming on the construction sector is a serious issue in today's world; this might be attributed to the emission of greenhouse gas (GHG) during the production process of Portland cement. Due to its advantages, cement plays a major role in the construction of civil infrastructures. Cement production is not only responsible for global warming and also creates a risk of raw material deficiency. To reduce the over exploitation of virgin materials, Limestone Calcined Clay Cement (LC3), with a proportion of Clinker 50 %, Limestone 30 %, Calcined Clay 15 % and gypsum 5 %, is found to be a suitable and sustainable alternative to preserve the ecosystem. As a result, attempts were undertaken in this work to create a mixture design approach for LC3 with the primary objective of developing higher compressive strength (CS) in a cost-effective manner. The relationship between the water to binder ratios and 28-d CS has been examined to suggest a conceptual mixture design strategy for LC3 rationally. The 28-day CS of 46.2 MPa has been observed. The suggested design technique has been presented step by step and validated using an example based on the guidelines illustrated by IS 10,262. The design technique aims to produce a concrete mix that meets specific strength, workability, and durability requirements while considering the environmental conditions and properties of materials available. The study emphasizes a systematic approach to concrete mix design, considering various factors like water-cement ratio, aggregate proportions, and workability requirements to ensure the resulting concrete meets the desired performance standards. Compliance with IS 10,262:2019 ensures that concrete used in construction is designed systematically and according to established guidelines, leading to higher quality and more predictable performance in structural applications. Further, to access the sustainability of the developed LC3 mix Life-Cycle Assessment (LCA) of LC3 was reported starting from raw material procurement to the production of concrete as the final product. In this LCA analysis, the monetary cost involved in the production of concrete, energy demand and GHG emission of the LC3 was compared with the conventional concrete. The result from the analysis revealed that LC3 possess superior performance in terms of energy requirement and GHG emission than the OPC concrete.

Detection of cracks in concrete using near-IR fluorescence imaging

Structural health monitoring of civil infrastructure is a crucial component of assuring the serviceability and integrity of the built environment. A primary material used in the construction of civil infrastructure is concrete, a material that is susceptible to cracking due to a variety of causes, such as shrinkage, creep, overloading, and temperature change. Cracking reduces the durability of concrete structures, as it allows deleterious environmental agents to penetrate the surface, causing such damage as corrosion of steel reinforcement and delamination of the concrete itself. Conventional crack detection techniques are limited in scope due to issues relating to pre-planning, accessibility, and the need for close proximity to the test surface. Contactless optical image monitoring techniques offer the opportunity to overcome these limitations and have the potential to detect cracks at a distance. Concrete has been reported to have a near-infrared (Near-IR) fluorescence line at a wavelength of 1140 nm when excited with red light. This work investigates the use of fluorescence imaging for the detection of cracks in cementitious surfaces using shallow angle incidence excitation red light. Light oriented at a shallow angle does not excite interior surfaces of cracks, which appear as darker features in images of fluorescing concrete. Artificial cracks with widths of 0.2–1.5 mm were readily imaged using a near-IR camera at distances of 0.5 and 1.3 m. An additional concrete sample with a 0.08 mm wide crack was produced using a flexure apparatus and was also imaged. It is worth noting that the 0.08 mm crack was detected despite its width being below the 0.1 mm pixel resolution of the camera, with the aid of digital image enhancement algorithms.

Green Public Procurement in Civil Infrastructure Construction: Current Performance and Main Project Characteristics

Green Public Procurement in Civil Infrastructure Construction: Current Performance and Main Project Characteristics

Cure cycle optimisation of structural epoxies used in composite civil infrastructure through the use of TTT diagrams

Adhesive bonding is becoming increasingly common in civil infrastructure construction due to the increased use of advanced composites. Due to the large scale of the structures and their application in outdoor settings, the conditions during adhesive curing are substantially different from those in other industries. However, little information exists on curing conditions of commonly used adhesives in civil infrastructure applications making the design of such adhesive-bonded joints difficult. This paper presents a study investigating different phase transitions involved in the curing process of Sikadur® −30, a commonly used adhesive in civil infrastructure applications. A time–temperature-transformation cure diagram was developed for this epoxy system. Oscillatory rheological data were used to determine the gel times. Differential scanning calorimetry tests were used to estimate the time taken for vitrification. Unreacted system and fully reacted system glass transition temperatures were determined to be −48 °C and 70 °C, respectively. Reaction kinetic simulations were carried out for the Sikadur® −30 epoxy system based on the obtained experimental data. The numerical predictions were validated against a comprehensive experimental program. Predictions were shown to be in excellent agreement with the experimental results. This research provides the pathway for structural composite designers to determine important information such as pot life and curing times under different environmental exposure conditions for better design of advanced composite bonded joints.

Війна в Україні: нові виклики для археології

As a result of the Russian aggression, which began in 2014, hundreds, if not thousands, of cultural heritage sites were destroyed or damaged to one degree or another. Against this background, the objects of archaeological heritage, which include settlements, hillforts, barrows, burial mounds (kurgans), etc., stand out. Work on collecting information on damaged archaeological sites began back in 2014. In 2016, after a monitoring mission to study the state of archaeological heritage in the war zone within the territory of Luhansk region, information began to be collected somewhat more actively. Starting from February 2022, when even more Ukrainian territory was subjected to military action, even more archaeological heritage sites were damaged or completely destroyed. Identification and analysis of cases related to the destructive impact of the war on the archaeological heritage is the main task for the near future. Therefore, there is an urgent need to develop methodological recommendations. The publication proposes the allocation of three conditional groups of locations of archaeological heritage objects: group A - objects in the zone of cessation of hostilities or in the zone of active hostilities in the unoccupied territory (controlled by Ukraine); group B - objects in the zone close to the front line, military operations were not carried out, but archaeological objects were damaged by the military (territory controlled by Ukraine); group C - objects in the zone where hostilities are no longer taking place, or in the zone of active military operations in the occupied territory. Given the existing information, a preliminary typology of the nature of damage to archaeological heritage objects was developed, which includes 6 items: 1. mounds with partially destroyed embankments as a result of shelling (presence of ruptures from explosions); 2. mounds damaged as a result of the arrangement of protective structures/support and observation point or firing points with the help of machinery or hand tools; 3. settlements, hillforts, and ground necropolis, on the day surface of which there are ruptures from explosions (the integrity of the object is damaged); 4. settlements, hillforts, and ground necropolis that were damaged or destroyed as a result of the construction of protective structures; 5. mined areas; 6. areas with objects of archaeological heritage allocated for large-scale construction of military infrastructure (Crimean Peninsula). The construction of civil infrastructure in the occupied territories is a topic for a separate study. In all cases, the degree of damage is indicated separately. The possibility of supplementing or correcting the data is not excluded, since the research process is at the stage of development. It also offers 4 ways of obtaining information about the facts of the destruction of archaeological heritage sites, including private messages, monitoring of social networks and specialized forums, visual monitoring, and research of satellite images. Key words: archaeological heritage, war, Ukraine, methodology.

Influence of Type of Sleeper–Ballast Interface on the Shear Behaviour of Railway Ballast: An Experimental and Numerical Study

The shear resistance at the sleeper–ballast interface of a ballasted track is an important contributor in maintaining track stability under faster and heavier axle loads where the ballast undergoes significant lateral sliding. Different types of sleeper–ballast interfaces based on the type of sleeper arrangements, such as concrete sleepers, timber sleepers, and under sleeper pads (USPs) attached to the concrete sleepers influence the lateral stability of railway tracks. Therefore, in this study the shear and degradation behaviour of ballast at concrete–ballast, timber–ballast, and USP–ballast interfaces were examined in the laboratory using large-scale direct shear tests under 60 kPa normal stress. The use of waste materials in the construction of civil infrastructure is gaining a lot of interest in the engineering community. Therefore, in addition to commercial USPs manufactured using raw materials, recycled USPs manufactured from granulates of end-of-life rubber tyres were also tested in this study. The discrete element modelling (DEM) approach was used to predict the shear behaviour of ballast at 30, 90, 120, 150, and 180 kPa normal stresses. The bonded particle model (BPM) was adopted in the DEM to simulate the effects of particle breakage during shearing. The results exhibited that both commercial and recycled USPs significantly improve the shear resistance at the sleeper–ballast interface while reducing particle degradation compared to concrete and timber sleeper interfaces.

Impact of Concrete Cracking: Case Study in Chilean Construction Projects

The construction sector is one of the most relevant to the world economy. Within it, the most used material is concrete given its excellent construction characteristics. However, this material suffers from different issues that can severely affect its performance and thus a construction project’s productivity. Of these issues, cracking is one of the most common and significant. It can affect the three most important aspects of construction: cost, deadline, and quality. Although its importance is recognized within the construction industry, to this day no clear vision exists as to the specific impact that cracking can have on a project. Consequently, this study aimed to determine that impact on mining, electrical, and civil infrastructure construction projects through a statistical analysis of 13 completed projects that suffered cracking. To obtain this information, companies involved in the construction of those projects in Chile were contacted. Additionally, this statistical analysis was complemented by a survey targeting professionals in the field who have dealt with cracking situations, with the objective of comparing the statistical results with the personal/professional survey responses. Analysis of project records indicated that concrete cracks represented a low percentage of total construction cost. This correlated with the surveyed professionals’ perceptions; however, the lack of proper recordkeeping by construction companies creates annual losses of several million in rehabilitation work, besides possibly hiding the real impact of cracking, creating an iceberg effect.

The Application of Advanced Information Technologies in Civil Infrastructure Construction and Maintenance

Information technologies have widely been used in the construction and maintenance of civil infrastructure. The advantages of information technologies provided a broader range of methods for infrastructure and enhanced its level of maintenance. However, a systematic summary of the research development of information technologies used in civil infrastructure is limited. This study aims to supplement this field by providing an objective, systematic summary of relevant literature in mainstream journals employing bibliometric retrieval and quantitative analysis from 2010 to 2020. The following results are obtained: (1) This study discusses the application of advanced information technologies in different phases and provides a critical analysis of the application of these existing information technologies, which includes wireless sensor networks (WSN), fiber optic sensing (FOS), building information modelling (BIM), radio frequency identification (RFID) and other advanced information technologies. (2) The digital twins can be used as tools for the planning and management of next-generation smart infrastructure, making the future of civil infrastructure smarter and more sustainable.

Comparison of permeabilities of quarry dust soil composite for application as eco friendly backfills

The principal objective of this research is to compare permeability properties of soil after inclusion of quarry dust into it. Two categories of soils are subjected to Constant head permeability test to study the differences in their permeabilities (group 1: soil without RHA, N = 17; group 2: soil with 5 % RHA, N = 17). The pre-test power and confidence intervals were chosen as 80 % and 95 % respectively for sample size calculation. Test results show that the permeability of soil decreases as a result of inclusion of quarry dust. A significant difference (2 tailed) between two groups of soil exists as the value of p is 0.0001 (p < 0.05) for the permeability values obtained. The permeability of novel quarry dust soil composite meets the permeability requirements of the design codes. Hence quarry dust has the potential to be utilized as a novel material which can be added with sandy soils in place of costly good quality earth fills for sustainable construction of civil infrastructures.

Experimental study on the effect of plastic waste strips and waste brick powder on strength parameters of expansive soils

Ethiopia has an abundance of expansive soils. This type of soil is weaker, having low strength and load-resisting characteristics in nature due to its difficulty in volume change when exposed to water. As a result, when saturated with water, the volume of such soils expands and contracts during dry seasons. In civil infrastructure construction, such soil should be removed or improved to be used as foundation soil. However, removing the soil leads to the extra costs of construction. On the other hand, improving requires increasing the stiffness and load-carrying capacity of the road by treating it with stabilizers, which help achieve low cost and good performance. This study aimed at treating such soils with waste-disposed materials to improve the soil's resistance to pressure and to reduce pollution. In this study, locally available expansive soil is treated with brick waste powder (20, 30, and 40 %) and waste plastic strips with (0.25 %, 0.5 %, and 0.75 %) percentages in weight. Disposed plastic water bottles are used. Atterberg limits, compaction, CBR, and unconfined compressive strength were performed to find an optimum percentage of mixes. Many trials were done by varying the percentages of PWS (plastic waste strips) and BP (brick powder). At the addition of 0.75% PWS and 30% BP, a significant change was observed with a considerable improvement in free swell, CBR, and unconfined compressive strength values. The study reveals plastic waste strips and brick waste powder were found to increase the strength qualities of expansive soils. This could pave the way for the use of waste materials in pavement construction while also lowering the environmental pollution.

Diesel Engine Exhaust Exposure in the Ontario Civil Infrastructure Construction Industry.

Diesel engine exhaust (DEE) is a known lung carcinogen and a common occupational exposure in Canada. The use of diesel-powered equipment in the construction industry is particularly widespread, but little is known about DEE exposures in this work setting. The objective of this study was to determine exposure levels and identify and characterize key determinants of DEE exposure at construction sites in Ontario. Elemental carbon (EC, a surrogate of DEE exposure) measurements were collected at seven civil infrastructure construction worksites and one trades training facility in Ontario using NIOSH method 5040. Full-shift personal air samples were collected using a constant-flow pump and SKC aluminium cyclone with quartz fibre filters in a 37-mm cassette. Exposures were compared with published health-based limits, including the Dutch Expert Committee on Occupational Safety (DECOS) limit (1.03 µg m-3 respirable EC) and the Finnish Institute of Occupational Health (FIOH) recommendation (5 µg m-3 respirable EC). Mixed-effects linear regression was used to identify determinants of EC exposure. In total, 149 EC samples were collected, ranging from <0.25 to 52.58 µg m-3 with a geometric mean (GM) of 3.71 µg m-3 [geometric standard deviation (GSD) = 3.32]. Overall, 41.6% of samples exceeded the FIOH limit, mostly within underground worksites (93.5%), and 90.6% exceeded the DECOS limit. Underground workers (GM = 13.20 µg m-3, GSD = 1.83) had exposures approximately four times higher than below grade workers (GM = 3.56 µg m-3, GSD = 1.94) and nine times higher than above ground workers (GM = 1.49 µg m-3, GSD = 1.75). Training facility exposures were similar to above ground workers (GM = 1.86 µg m-3, GSD = 4.12); however, exposures were highly variable. Work setting and enclosed cabins were identified as the key determinants of exposure in the final model (adjusted R2 = 0.72, P < 0.001). The highest DEE exposures were observed in underground workplaces and when using unenclosed cabins. This study provides data on current DEE exposure in Canadian construction workers. Most exposures were above recommended health-based limits, albeit in other jurisdictions, signifying a need to further reduce DEE levels in construction. These results can inform a hazard reduction strategy including targeted intervention/control measures to reduce DEE exposure and the burden of occupational lung cancer.

Experimental Study on the Effect of Plastic Waste Strips and Waste Brick Powder on Strength Parameters of Expansive Soils

Expansive soils are found abundantly in Ethiopia. This type of soils is weaker, having low strength and load resisting characteristics in nature due to their difficulty in volume change when it comes into contact with water. The volume of such soils becomes swell when saturated with water and shrinks during dry seasons. In civil infrastructure construction, such soil either should removed or improved to be used as foundation soil. Removing the soil leads to the more extra costs of construction. Improving, on the other hand, requires increasing the stiffness and load-carrying capacity of the road by treating it with stabilizers, which helps in achieving a low cost and good performance. This study aimed at treating such soils with waste materials for improving the strength of the soil against pressure, and to reduce environmental pollution. In this study, locally available black cotton soil is treated with brick waste powder (20, 30, and 40 %) and plastic strips with (0.25 %, 0.5 %, and 0.75 %) percentages in weight. Different tests including atterberg limits, compaction, CBR, and unconfined compressive strength were performed to find an optimum percentage of mixes. Many trials were done by varying the percentages of PWS (plastic waste strips) and BP (brick powder). At an addition of 0.75% PWS and 30% BP, significant change was observed with huge improvement in CBR, free swell and unconfined compressive strength values.

A Framework for Interpreting Lateral Swelling Pressure in Unsaturated Expansive Soils

Lateral swelling pressure (LSP) develops when expansive soil volume increment associated with water infiltration is restrained in a confined domain, for example, due to construction of civil infrastructure. In this paper, initially a flowchart is developed to highlight various key factors that influence the LSP mobilization according to lab and field studies collected from previous literature studies. Then extending unsaturated soil mechanics, a theoretical framework is proposed for illustrating the LSP mobilization in the field against retaining structures and pile foundations under different boundary conditions, respectively. An example problem for a basement wall and a pile foundation constructed in a typical expansive soil from Regina, Canada, is presented to illustrate the proposed theoretical framework. The framework and corresponding analysis presented in this paper can facilitate to provide rational designs of geotechnical infrastructures in expansive soils.

Precise object detection using adversarially augmented local/global feature fusion

Object detection, which aims at recognizing or locating the objects of interest in remote sensing imagery with high spatial resolutions (HSR), plays a significant role in many real-world scenarios, e.g., environment monitoring, urban planning, civil infrastructure construction, disaster rescuing, and geographic image retrieval. As a long-lasting challenging problem in both machine learning and geoinformatics communities, many approaches have been proposed to tackle it. However, previous methods always overlook the abundant information embedded in the HSR remote sensing images. The effectiveness of these methods, e.g., accuracy of detection, is therefore limited to some extent. To overcome the mentioned challenge, in this paper, we propose a novel two-phase deep framework, dubbed GLGOD-Net, to effectively detect meaningful objects in HSR images. GLGOD-Net firstly attempts to learn the enhanced deep representations from super-resolution image data. Fully utilizing the augmented image representations, GLGOD-Net then learns the fused representations into which both local and global latent features are implanted. Such fused representations learned by GLGOD-Net can be used to precisely detect different objects in remote sensing images. The proposed framework has been extensively tested on a real-world HSR image dataset for object detection and has been compared with several strong baselines. The remarkable experimental results validate the effectiveness of GLGOD-Net. The success of GLGOD-Net not only advances the cutting-edge of image data analytics, but also promotes the corresponding applicability of deep learning in remote sensing imagery.

Civil Liability of Construction Service Providers Against Building Failures in the Taxiway Construction Agreement of Kuala Namu International Airport

Medan, as a metropolitan city, has several advantages, such as the strategic location for various economic activities. As the capital of North Sumatra Province, Medan continues to develop by building many infrastructures to support business activities such as airport, seaport, apartments, toll roads, hotels, hospitals, housing properties, and others. Constructing infrastructure in Medan requires a building contract made by a notary public as a general official authorized to make authentic deeds. Construction is the activity of building facilities and infrastructure which includes building construction, civil infrastructure construction, mechanical and electrical installations. An example of the construction work is the establishment of taxiways through the operational cooperation between PT Adi Karya (Persero) Tbk and PT Duta Graha Indah Tbk. This study applies an analytical descriptive approach utilizing a normative legal method. The results show that the implementation of taxiway construction complies with the Joint Operation Agreement between PT Adi Karya (Persero) Tbk and PT Duta Graha Indah Tbk under Law Number 2 of 2017 concerning Construction Services applicable for all projects throughout Indonesia, which states that the construction service providers must repair construction failures during the maintenance period.

Unconfined Compressive Strength of Geopolymer Cement

Red mud is produced by the production of alumina and its disposal is now a global problem. Every year large amounts of red mud are released from the bauxite calcination method and its use has become an urgent problem. The initial study investigates the possible reuse of red mud through geopolymerization and itsreaction with other solid waste, such as fly ash. This document offers a concept that studies the geopolymerization of red mud, the main industrial leftover from the refining of alumina and fly ash, an industrial leftover from the burning of coal, consumingminimummaterials. Different synthesis factors (for example, the ratio of red mud / fly ash, sodium metasilicateNonahydrate solution in a solid mixture (ratio of red mud and fly ash), diverse concentrations of sodium metasilicateNonahydrate solution, etc.). They are altered to have an effect on the evaluation of mechanical properties of the final geopolymer product. In this study, the ratio of red mud to fly ashwas maintained at 50:50 as a constant ratio, the solution to the solid mixture as 1 and the change in concentration of the sodiummetasilicateNonahydrate solution (2M-6M). The outputs of the unconfined compression test display that these aspects have a substantialimpact on the mechanical characteristics of the synthesized geopolymer. Depending on the synthesis circumstances, the unconfirmed compressive strengths range from 2.391 kg / cm² to 10.963 kg / cm² and high values can be compared with some types of Portland cement. The results shows the two most important industrial leftovers, red mud and fly ash, can be reutilised to produce geopolymers that can substitute Portland cement and can further be used in the construction of civil infrastructure.

Measuring the Sustainability of Construction Projects throughout Their Lifecycle: A Taiwan Lesson

Researchers have proposed many industrial or national sustainability evaluation indicator systems during the past decade, although there has not yet been a project-level sustainability evaluation system for the evaluation and execution monitoring of the sustainability status for a construction project. Without such an evaluation system, it will be difficult for the planners to plan the sustainable project objectives, for the contractors to select the sustainable execution alternatives, and for the facility managers to operate sustainable constructed facilities. To meet the abovementioned requirements, this paper presents an effort conducted in Taiwan to propose a Construction Project Sustainability Assessing System (CPSAS) considering three pillars of sustainability: environmental, social, and economic, based on the theoretical backgrounds from the literature and former successful sustainable projects. The proposed CPSAS comprises four levels: Level 1, 3 main pillars; Level 2, 8 categories; Level 3, 19 sub-categories; and Level 4, 31 indicators. Different selections of indicators for application in different project phases are suggested according to the prioritization via questionnaire surveys. A procedure for sustainable project management with the proposed CPSAS is suggested to the project management team. Finally, three green building projects and two civil infrastructure construction projects of Taiwan were tested to demonstrate the feasibility of the proposed CPSAS. It is concluded that the proposed CPSAS is useful for construction stakeholders to achieve sustainability more effectively during the execution of a construction project.

Compressive Strength of Compacted Clay-Sand Mixes

The use of sand to improve the strength of natural clays provides a viable alternative for civil infrastructure construction involving earthwork. The main objective of this note was to investigate the compressive strength of compacted clay-sand mixes. A natural clay of high plasticity was mixed with 20% and 40% sand (SP) and their compaction and strength properties were determined. Results indicated that the investigated materials exhibited a brittle behaviour on the dry side of optimum and a ductile behaviour on the wet side of optimum. For each material, the compressive strength increased with an increase in density following a power law function. Conversely, the compressive strength increased with decreasing water content of the material following a similar function. Finally, the compressive strength decreased with an increase in sand content because of increased material heterogeneity and loss of sand grains from the sides during shearing.