CivilEng, Volume 3, Issue 2 (June 2022) – 22 articles

Pavement friction is an important topic addressed by transportation agencies to reduce the number of traffic crashes and fatalities caused by poor friction between tires and pavement surface. Pavement friction management (PFM) provides the essential tools and techniques to effectively evaluate pavement friction conditions and provide informed maintenance decisions using surface treatments. State Departments of Transportation (DOTs) utilize various engineering practices to collect and analyze friction-related data, crash data, and traffic data. In addition, state DOTs tend to employ different techniques and policies to manage the pavement friction depending on budget levels, strategic objectives, and climate conditions. Due to these diversified practices in friction management, in this study, we intend to provide a comprehensive review of the state of the practice among state DOTs. Online surveys were analyzed using descriptive and statistical correlation analyses to study the experience of state DOTs with managing pavement friction, considering feedback from 32 state DOTs in the USA. Exploring the methods to manage the pavement friction used by state agencies will help researchers and officials know more about the strategies towards an effective PFM. It also presents opportunities to enhance the approaches of the followed programs and highlight the gaps of the current practices. The results obtained from the survey identify the practical policies and propose future enhancements to maximize the value of pavement assets and promote safety. Full article

The northern stretch of the Arun watershed in East Nepal is dominated by steep slopes and rugged topography and experiences extensive landslides each year. Reliable landslide susceptibility assessment can potentially be an important tool for risk evaluation and mitigation in the Himalayas. The present study explores two GIS-based bivariate statistical methods, the weight of evidence method and the frequency ratio method to assess the landslide susceptibility of the study area. Seven major variables including slope angle, slope aspect, slope shape, geology, stream proximity, stream power index and land use were examined as the major contributing factors to landslide occurrences in the assessment. The landslide susceptibility map produced from these two methods are characterized by four zones of very low, low, moderate and high susceptibility. The landslide percentage of each zone turns out to be consistent with the order of its susceptibility. The results suggest that the weight of evidence method is more sensitive to the spatial variation of relevant factors; both methods produced fairly reliable results, as confirmed by a success rate of 75% for the weight of evidence method and 71% for the frequency ratio method. The present study demonstrates that the quantitative assessment methods explored may have a promising potential for landslide assessment and prediction in the Himalayas. Full article

This paper presents results from experimental and analytical investigations conducted to evaluate the lateral load behavior and capacity of steel-plate composite (SC) wall-to-reinforced concrete (RC) basemat connections. Two SC wall-to-reinforced concrete basemat connection specimens were tested. These SC wall specimens had a height-to-length ratio of 0.6 and did not include boundary elements. The experimental results include the lateral force-displacement (V-Δ) responses of the specimens and observations of local damage such as steel plate local buckling and concrete crushing. 3D finite element models were developed and benchmarked using the experimental results. The benchmarked models were used to conduct analytical parametric studies, expand the database, and gain additional insights into the behavior of SC wall-to-RC basemat connections. The parameters included in analytical investigations were the wall aspect ratio (h/lw), reinforcement ratio (ρ), and wall thickness (T). Full article

This study focusses on a method for estimating the urban recharge and evaluating the ground water quality for drinking and irrigation purposes. The study was carried out in the Liverpool Local Government Area of New South Wales, Australia, and it included year-long monitoring of four boreholes for the water table depth and water quality. Average depth of water table was in the range of 1 to 4 m from the land surface. The pattern of variations in the water table depth (WTD) varied across the four boreholes. The WTD variations between borehole 2 (BH2) and borehole 3 (BH3) were similar, but significantly different variations were exhibited in BH1 and BH 4, with BH1 showing a quicker response to rainfall events. The presence of lake appears to have influenced the recharge pattern in the adjacent area as reflected in the WTD variations in BH3 and BH4. The recharge rates for BH3 and BH4 was about 2 to 5 times higher than those observed for BH1 and BH2, which are located at a relatively greater distance from the lake. This indicates that the presence of urban lakes can influence recharge rate in the area. Water quality analysis indicated higher salt and turbidity levels, which may be attributed to the local geology (the Wianamatta group) present in the study area and/or possible saltwater intrusion. This has implications for the treatment cost associated with the supply of the groundwater for drinking and irrigation purposes. Pearson’s analysis indicated a significant correlation between EC, TDS, Turbidity and pH. The turbidity of groundwater varied between 33 and 530 NTU, indicating that the turbidity may have been affected by the dissolution of salt deposits via colloidal particles. Significant variations in groundwater quality during rainy periods, also, indicated the existence of groundwater recharge in the study area. This study highlights the issues associated with the groundwater recharge and quality management in urban landscapes and provides a basis for further research. Full article

Due to the impacts of carbon emissions on climate change and the expected dramatic increase in global cooling demand by 2050, it is of a paramount importance that the required energy to cool buildings is accurately predicted. This ensures that equipment is appropriately sized, which ultimately reduces energy consumption and global carbon emissions. CIBSE and ASHRAE standards are both widely adopted for cooling load predictions, but they adopt different calculation methods, with CIBSE adopting admittance and ASHRAE adopting radiant time series (RTS), which produce significantly different results in cooling load. This study comparatively and qualitatively evaluates the CIBSE admittance and ASHRAE RTS cooling load models by analysing their structures and key input parameters for a mock-up building to identify inconsistencies between the two methods. There were flaws within both models that resulted in the CIBSE method underpredicting the cooling load, whereas the ASHRAE method typically overpredicting it. This resulted in a maximal average difference of over 60%. The substantial predicted cooling load difference was mainly caused by the ASHRAE RTS model, which was highly receptive to solar gains, and it consequently led to overprediction in cooling load when compared to the CIBSE admittance model. Full article

The root cause of premature failures in relatively thin (<50 mm) asphalt surfaced roads is often a challenge to solve during forensic investigations in South Africa (SA). This description is based on peer review type discussions with forensic investigations experts as well as published research papers. The areas of ignorance or areas where research effort is needed are identified. These observations serve to identify areas of new knowledge needed in terms of actual verification with measurements, measurement technology, and modeling of the observed phenomena. The main objectives of this discussion paper are to highlight the evolution of distress development in asphalt layers starting from the identification and description of the kind of microcracks, effects of microcracks in the debonding of the asphalt layer from lower layer, and vehicle–pavement interactions (VPI) of moving truck wheels focusing on the thin asphalt layer. Specific reference is made to the need to measure and model the effects of bow waves in front of and next to the loaded rolling wheel. Full article

Brick masonry veneer walls connected to infill walls inserted in a reinforced concrete (RC) frame are a common constructive system in Portugal. The stability of the veneer wall is ensured by ties that make the connection with the masonry infill walls. These ties enable the transferring of out-of-plane loads to the main structure due to wind, and particularly due to earthquakes. However, the characterization of the seismic behavior of these tie connections is an insufficiently explored topic. The present paper shows a numerical investigation that aims to simulate experimental results of tension and compression tests performed on masonry prisms connected by means of steel ties. The main objective of the present research is to obtain a better understanding of the complex structural behavior of this specific construction system to then develop simplified numerical tools to be used in engineering practice for the seismic design and retrofitting of brick masonry veneer walls. The numerical results match well the experimental ones, and the validated approach can be used in the future to carry out parametric analyses to evaluate the influence of material and geometric properties of the tie and masonry, as well as the type of action and construction details. Full article

Sustainable built environment has been the primary focus in academic and industrial fields in recent years. The major forces behind sustainable engineering are the rise in climate-related disasters, constant challenges in the energy sector, and a substantial shift in consumers’ consciousness toward conserving natural resources. Further, many professional bodies have developed guidelines and specifications to implement sustainable practices and rate their impacts. Regardless, promoting analytical procedures for creating a context-sensitive design requires professionals to become familiar with standard sustainable practices and feel comfortable implementing more innovative materials and techniques in civil engineering design. In addition, the socio-political environment and macro-economic culture interact with engineering decisions. Hence, these considerations are necessary to deploy these elements in developing communities through best management practices during the lifecycle of sustainable and resilient projects. This paper endeavors to review these practices using lessons learned from applied examples and existing literature. Discussions cover various aspects of project development, from planning to demolition. Recommendations address challenges and opportunities in the sustainable development of resilient built infrastructure in developing regions. Full article

The strengthening of existing reinforced concrete structures (RC) with carbon reinforced concrete (CRC) has a high potential to save resources and to increase the lifespan of the whole strengthened structure immensely. However, when strengthening structures with CRC, in some cases, failure due to concrete cover separation is detected, leading to the fact that the potential of the carbon reinforcement cannot be exploited. The prediction and prevention of this type of failure is the subject of current research. In this paper, a strut-and-tie-model is presented for calculating a critical tensile force leading to failure due to concrete cover separation. Additionally, possible methods to avoid that kind of failure are suggested. One of these is doweling the ends of the strengthening layer. This paper presents the first experiments to test this method, which show that doweling the strengthening layer leads to much higher failure loads compared to a structure without doweling. However, further investigations have to be examined to verify these first results. Full article

Economically disadvantaged coastal communities face severe damage and casualties, which can be attributed to storm surges. Excessive amounts of inundation should be considered to a similar level to wind speeds and heavy rains that communities commonly prepare for amidst a hurricane event. Marginalized residents, such as residents of color, disabled residents, elderly residents, and residents occupying low-income housing, suffer from storm surge events. Coastal resiliency plans are bottlenecked by factors, such as residential stability, ability to relocate, and insurance coverage, all of which are inequitably constrained for marginalized communities. This exploratory study reviews the previous literature on wireless emergency alert (WEA) equity critiques and spatial analysis of the WEAs sent to coastal Virginia communities. Two research questions are explored in this paper: (1) How does the previous literature critique equity in wireless emergency alerts? (2) How many households are below the poverty line in areas where storm surge warnings have been sent? To improve the utilization of WEAs for the protection of low-income community members, there is evidence to support the increase in the frequency of message delivery and improving the call-to-action text. This paper sets the stage for future policy analyses and message design experimentation on emergency communication in coastal regions. Full article

Scour, caused by swiftly moving water, can remove alluvial sediment and soil, creating holes surrounding a bridge component and compromising the integrity of the bridge structure. Such problems can be equally critical for bridges with piers-on-bank bridges subjected to severe storm and flooding issues. In this paper, the Phillips Road Bridge over Toby Creek (35°18′28.2″ N 80°44′16.6″ W, Charlotte, NC, USA), a pier-on-bank bridge with critical/significant local scour holes and deep riverbank erosion cuts was selected as case study bridge. To investigate the scour effect on the bridge with pier-on-bank performance, the scoured area around a single pier is first quantified using a terrestrial laser and then modeled using nonlinear finite element (FE) analysis, where the local scour is modeled as progressive mass losses using the Element Removal (ER) technique. The FE results are compared to the design loading scenario and the results substantiated that the local scouring could cause large deflection and increased bending moment on the bridge pier. Full article

Warm Mix Asphalt (WMA) is a set of technologies that uses additives to reduce binder viscosity and increase mixture workability, which provides a complete coating of aggregates at lower temperatures around 100 °C to 130 °C. Organic wax or Sasobit is one of the additives that can be used for this purpose. It reduces the viscosity at the melting point of the wax, which allows the production of asphalt mixes at lower temperatures. This attempt proposes new relationships for elastic modulus, indirect tensile strength (in dry and wet conditions), dynamic modulus, fatigue, and rutting resistance of WMA asphalt samples with various Sasobit percentages. Findings show that Sasobit improves modulus of elasticity, dynamic modulus, and rutting resistance. However, it lessens the tensile strength slightly. Although Sasobit enhances the flexural stiffness, it drops the number of loading cycles, which means lower fatigue resistance. Results also showed that at 20 °C and 10 Hz frequency, the resilient modulus, dynamic modulus, and flexural stiffness of WMA improved 53%, 27%, and 39%, respectively, compared with HMA. Rutting resistance at 60 °C improves 226% in WMA with 6% Sasobit compared to the HMA mix. Full article

The freeze-thaw behaviour of bonded fasteners in concrete is assessed according to the European Assessment Document 330499-01-0601 with freeze-thaw condition tests, which include 50 temperature cycles with a duration of 24 h between −20 °C and +20 °C on constantly loaded anchors. It is assumed that one cycle is equivalent to the temperature difference, which a bonded fastener undergoes in one year. Based on an analysis of a 28-year time series of air temperature data for Austria respecting the Alpine region, a modified test protocol with a temperature amplitude of 65 °C between −20 °C and +45 °C is compiled without a predefinition of the number of cycles, in order to simulate temperature differences that occur under real climatic conditions. The experimental test results obtained for both test procedures demonstrate that the stabilization of the displacements for the modified test series occurred after 185 temperature cycles, compared to the 50 cycles for the standard method. This means that an increase in the temperature amplitude of 25 °C in the higher temperature range leads to an approximately 3.5 times higher number of required temperature cycles until displacement stabilization is reached. It is concluded that the definition of the used temperature range for freeze-thaw testing in conjunction with climatic data should be critically considered, in order to possibly adapt pure freeze-thaw tests towards experiments that take into account real annual temperature differences. Full article

Growing demand for road infrastructures and accompanying environmental footprint calls for the replacement of pavement materials with recycled options. The complexities in real-world usability are dependent upon project-specific characteristics and are affected by budgetary constraints of local governmental agencies, material applicability, and climatical conditions. This study conducts a comprehensive lifecycle cost analysis (LCCA) of an urban highway section “E10” in the hot Middle Eastern climate of Abu Dhabi, where virgin asphalt usage is dominant, using actual cost data under multiple scenarios and recycled construction waste (RCW) usage across aggregate layers and recycled asphalt pavement (RAP) across wearing, binder, and asphalt base courses. Blast furnace slag as partial cement replacement for road concrete works is also analysed. Impacts across all lifecycle stages from initial earthworks and construction to routine maintenance and operation were compared. Results found that cost of sustainable construction is lower. Cost reduction was highest for RAP and RCW usage, particularly when the usage was accumulated. The optimum cost scenario used 25% RCW in the sub-base, 80% RCW in the unbound base, 25% warm-mix asphalt (WMA) RAP in the asphalt base, 15% warm-mix RAP in the binder and wearing courses, and 65% slag for concrete roadworks and resulted in USD 2.6 million (15%) cost reduction over 30 years from 2015 to 2045. Full article

In curtain wall applications, anchor channels are frequently installed near the edge of composite slabs with profiled steel decking. The complex concrete geometry of these floor slabs affects the capacity of all concrete failure modes, but there are currently no guidelines or investigations available on this topic. The main objective of the present research is to investigate how the position of anchor channels and the complex slab geometry influence the tensile capacity of anchor channels. For this purpose, an extensive numerical parametric study was performed using the 3D nonlinear FE code MASA, which is based on the microplane constitutive model. In order to validate the numerical results, an experimental program was carried out for some of the configurations possible in practice. Based on the results, recommendations are given for the reduction in the tensile capacity of anchor channels in composite slabs with profiled steel decking. Full article

Climate change is causing more frequent extreme weather events. The consequences of increasing global temperature on the operating cost of existing buildings, and the associated health, safety, and economic risks were investigated. Eight cities in Ontario, Canada, across climate zones 5 to 8, were selected for this study. Statistical models were employed to forecast daily temperatures for 50 years. The impact of climate change on buildings’ heating and cooling demands for energy was measured as changes in heating degree days (HDD) and cooling degree days (CDD) compared to current design requirements. The results predict an increase in the demand for cooling and a decrease in that for heating within the next 50 years. A drop in the total HDD and CDD is shown which reflects a more comfortable outdoor thermal condition. Risk to human health attributable to the increase in global temperature is negligible. Full article

Agricultural residues/by-products have become a popular choice for the manufacturing of building materials due to their cost-effectiveness and environmental friendliness, making them a viable option for achieving sustainability in the construction sector. This study addresses the utilisation of two agro-wastes, i.e., eggshell and walnut shell, in the manufacture of unburnt clay blocks. The experiments were carried out on three series of samples in which first eggshell (10–50%) and walnut shell (5–20%) were incorporated individually and then combined (5% walnut, 10–30% eggshell) in the mixture to assess their influences on the physical and mechanical properties of the unburnt clay blocks. This study performed the following tests: Density, capillary water absorption, linear shrinkage, flexural and compressive strength. The results indicated that eggshell enhanced the strength relative to the control sample when the materials were employed individually, but walnut shell lowered it. Moreover, combining the two materials in the mixer reduced the strength of the samples even further. Nevertheless, the inclusion of the waste materials decreased the density, capillary water absorption coefficient and linear shrinkage of the samples. The findings indicate that eggshell has great potential for unburnt clay block manufacture. However, walnut shell integration needs further research. Full article

Roads account for a major part of energy/resource consumption and emission of GHGs, such as CO₂, PM, NO_x, O₃, etc., due to high demand for virgin materials, specifically in developing regions. The applicability of recycled materials, such as recycled asphalt pavement (RAP) and other alternative approaches for, e.g., warm-mix asphalt (WMA), in developed countries is hindered by project-specific constraints and lack of empirical studies in these regions. Lifecycle assessment studies on the usage of these road options from actual projects in the developing countries can aid decision makers choose sustainable material approaches by providing case study examples as guidelines. To that end, this study analyses environmental in/out-flows for a traditional approach and multiple green approaches (RAP and WMA) for a major highway section in Abu Dhabi through a 30-year (2015–2045) lifecycle approach. Roadworks were modelled in SimaPro according to real-world conditions, and the expected burden mitigation in each stage is calculated. Benefits of using optimum RAP-based options and a virgin-material-based WMA case against the baseline virgin material case were also investigated. Results showed benefits of WMA as higher than replacing virgin asphalt with recycled asphalt (25% RAP asphalt base, 15% RAP binder and wearing courses). Land use (19%) and energy consumption (16%) showed the highest reduction, followed by ozone depletion (14%), ionizing radiation (11%), PM (8%), acidification (7%) and global warming potential (6%) across all pavement lifecycle stages and environmental indicators. Similar results were obtained for other scenarios with lesser degrees of reduction, which show the significance of replacing HMA with WMA for real-world projects, specifically in mega road projects in Abu Dhabi and the Middle East towards cutting the significant carbon footprint of asphalt pavements. Full article

Digging trenches on roads, sidewalks, or banks to accommodate public demands is required for the installation of water pipelines, natural gas lines, electric cables, and optical fibers. The soils extracted from these trenches always have substantial environmental and economic consequences, as these soils are frequently regarded as waste due to their poor engineering properties. As a result, a suitable location and method for disposing these excavated soils must be found, and this procedure is exceedingly costly, time consuming, and environmentally unfriendly. It is far more efficient to reuse these excavated soils for refilling the same trenches. This study is a part of a French national project. The national project aims to dig 5 to 25 cm wide trenches to install public utilities and to refill them using the same excavated material in the form of self-compacting mortar. The goal of this research is to determine the best ecofriendly binder for the soil excavated from various sites by conducting laboratory-scale physio-chemical and mechanical testing. This study examined the unconfined compressive strength (UCS) assessed by both destructive and non-destructive (ultrasonic) testing methods. By utilizing low CO₂-emitting ecofriendly binders incorporating industrial byproducts (fly ash and GGBS), this work has broadened the possibility of reusing trench cuttings to refill the same trenches. Full article

The construction sector is responsible for a great environmental impact. The cement industry, which is included in this sector, emits about 650 to 800 kg of CO₂ per each tonne of cement produced, being one of the most polluting industries in terms of greenhouse gas emissions. The cement manufacturing process releases about 7% of the total worldwide CO₂ emissions. However, concrete and cement-based materials present CO₂ uptake potential during their service life and post-demolition through carbonation processes. The carbonation reactions rate depends on several factors, namely type and content of cement, porosity of concrete, temperature, relative humidity and exposure conditions area. Therefore, to estimate the CO₂ capture of concrete during its life cycle is not a straightforward calculation. Some studies have been developed using different methodologies in order to evaluate the CO₂ potential of cementitious elements in service and post-demolition. This paper reviews the documented approaches that quantify the CO₂ uptake of concrete over time, summarizing the assumptions adopted for each previous work. Overall, it was concluded that part of the CO₂ emissions released during cement production are reabsorbed by concrete products during their life cycle, which partially offsets the environmental impact and reduces the CO₂ footprint of the cement industry. Full article

There is a need to move society in a sustainable direction. One way to contribute to this move is to change to more sustainable transport modes, such as cycling. To increase cycling, the infrastructure is important, and good quality cycle paths are needed. However, little is known about the degradation of cycle paths. This paper aims to investigate what modes of pavement distress are found on municipal cycle paths in Sweden, and what probable mechanisms lie behind such distress; these are determined based on questions from a state-of-practice survey, interviews, and a literature review. The main findings are that the most commonly stated distress modes are surface unevenness followed by longitudinal cracks, and the most commonly stated causes of distress are ageing, followed by structural interventions, and roots and vegetation. The results also show that for several distress modes, there are probable connections with climatic factors such as temperature and moisture, as well as with the population size of the urban areas. Objective data are needed regarding traffic load and the climatic factors that affect cycle paths, along with information on their structural design, to better understand their degradation. Full article

A three-dimensional non-linear finite-element model (FEM) was constructed using a commercial software (ATENA-Studio) to investigate the transverse load distribution behavior of adjacent precast prestressed concrete box-girder bridges. An innovative connection between box girders was used, where transverse post-tensioning was applied at the top flanges only eliminating the need for intermediate transverse diaphragms. The FEM was validated in terms of deflections, strains, cracking and ultimate loads against experimental results previously reported by the authors. The validated FEM was then used to perform a parametric study investigating the influence of adding concrete topping, load location, and bridge width on the transverse load distribution behavior of the newly developed connection. The results of the FEM demonstrated the efficiency of concrete topping in limiting mid-span deflections up to 25%. Additionally, the maximum live load moment distribution factors (LLMDFs) for different load locations and bridge widths were evaluated. Full article