Civil Engineering Infrastructures Journal
Volume:57 Issue: 2, Dec 2024

Industries produce large amounts of electric induction furnace steel slag (EIF) and copper slag (CuS) as waste, and their disposal poses serious economic and environmental issues. The use of these slags in pavement could ease environmental concerns and promote the conservation of non-renewable resources. This paper is based on an experimental investigation into the potential for employing EIF and CuS at 0, 5, 10, 15, 20, and 25% as a partial replacement of fine Natural Granite Aggregate (NGA), whose size ranges from 4.75 mm to 0.075 mm, in producing dense Hot Mix Asphalt (HMA) mixes. The physical, chemical, morphological, and expansive properties of EIF and CuS were investigated. The Marshall method of mix design was adopted to produce HMA mixes. The results showed that for EIF-based HMA mixes, stability, Indirect Tensile Strength (ITS), and rutting resistance increased, whereas for CuS-based HMA mixes, these properties decreased but satisfied their required permissible criteria. The Tensile Strength Ratio (TSR) of EIF and CuS-based HMA mixes was found to be increased. The findings of this study indicated a high possibility for using EIF and CuS as aggregates, and a replacement level of 20% of these slags in HMA mixes was suggested as optimal.

Concrete is a commonly used construction material due to its favourable engineering properties, such as high compressive strength, good durability, and resistance to corrosion. Accurate predictions of the compressive strength of this material significantly reduce the time and effort required by laboratory tests. The current paper aims to compare the performance of prominent machine learning-based approaches used for predicting the compressive strength of concrete. In addition, 11 historical datasets, collected from the literature, are used. The diversity of the input features, the data dimensionality, and the number of instances can be helpful to evaluate the generalization capability of the employed machine learning models. Repetitive data sampling processes, consisting of 20 independent runs, are carried out to obtain the machine learning models’ performances. Through experiments, it can be shown that the gradient boosting machines attain the best performance. Notably, the extreme gradient boosting machine has achieved the best outcome in five historical datasets.

This paper investigates the performance and efficacy of Quintuple Friction Pendulum (QTFP) isolators under a sequence of near-fault foreshock, mainshock and aftershock earthquake events. The QTFP isolator is an advanced base isolation device utilized in Reinforced Concrete (RC) structures to alleviate damage from severe seismic activity. Despite its proven ability to restrict structural responses and meet particular performance goals under severe seismic excitation, comprehensive analyses of QTFP isolators performance under sequential earthquakes are scarce. This research employs finite element analysis to explore the seismic behavior of RC structures equipped with QTFP isolators during such sequences. It also assesses the effectiveness of QTFP isolators by evaluating the seismic behavior of base-isolated RC structures subjected to sequence earthquakes. In general, the sequence of foreshock, mainshock and aftershock earthquake events critically impacts the structural response, with the foreshock producing the highest base shear, inter-story drift and acceleration responses. Furthermore, the aftershock accounted for the most considerable input, damping, and hysteretic energies. The research offers insights into the hysteresis behavior of the isolators, particularly during the mainshock, where the combination of 2.15 seconds period and 10% damping showcased the most extensive hysteresis loop cycles. This study underscores the significance of QTFP isolators in enhancing the seismic resistance of RC structures, while shedding light on their performance under different earthquake sequences.

In the construction of Roller compacted Concrete Dams (RCD), two types of internal and external concrete are used; thermal cracks are occurred due to hydration of various cements in this type of dams. Ignorance of this issue can lead to crack formation in the susceptible points of the dams. In this research, the behavior of the thermal cracks existed in the RCD body, is investigated through translational and rotational components of the earthquake. Three-dimensional Finite Element (FE) model of the concrete dam is built in Abacus software, and the model was subjected to 7 earthquake records. After validation of the model, the propagation of the crack existed in the dam body is evaluated using fracture mechanics criterion. The results of the FE analysis show that the existence of the cracks in the susceptible points of the dam, leads to propagation of these cracks during an earthquake. Especially, with considering the rotational component of the earthquake which has the significant contribution in the obtained values of the crack propagation criterion; this contribution is related to the frequency content of the earthquake, which can lead to an increase of the crack propagation energy up to 50 percent in some earthquake records.

The material properties of geotextiles play a significant role in shaping the long-term behavior of reinforced soils, potentially leading to issues like instability and excessive deformation. To address these challenges, thorough research into geotextile materials rheological properties and nonlinear behavior is essential. This study specifically focuses on the investigation of six commonly employed isotropic hyper elastic models (Neo-Hooke, Mooney-Rivlin, Ogden, Yeoh, Arruda-Boyce and Van der Waals) for describing the behavior of PET woven geotextiles in civil engineering applications. These models are fine-tuned through uniaxial tension tests conducted in warp and weft directions. Upon analyzing the experimental data, it becomes evident that the Yeoh and Neo-Hooke models exhibit exceptional accuracy in predicting geotextile behavior. The primary objective of this study is to advance our comprehension of how geotextiles react to varying loads, achieved through a combination of testing and finite element simulations. The robust correlation between experimental and simulation results significantly contributes to developing dependable hyper elastic material models tailored for geotextiles. This research framework holds considerable potential value for manufacturers and engineers as it equips them with practical tools to address concerns associated with soil-structure interaction in their projects.

Investigating the impact of fly ash on concrete strength and durability in the challenging marine environment of the Persian Gulf is crucial due to sulfate attacks and salt effects. This study aims to enhance the lifespan of these structures by increasing strength and reducing permeability. The innovative approach involves microstructural assessment of fly ash’s influence on Calcium Hydroxide (CH) and C-S-H nanostructure formation in concrete. Around 120 concrete samples with varying fly ash content were exposed to the Persian Gulf for three months, undergoing compressive strength, permeability, and microstructural analysis. Results reveal fly ash addition decreases permeability and boosts concrete strength. Notably, concrete containing 10% fly ash exhibited a 15.4% strength increase and reduced permeability from 22.4 × 10-7 cm/h to 8.98 × 10-7 cm/h after 90 days. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis showcased CH reduction and enhanced C-S-H nanostructure, bolstering concrete durability. This study offers valuable insights for engineers constructing coastal Persian Gulf structures, indicating fly ash augmentation enhances microstructural properties, reduces permeability, and bolsters strength.

The main objective of this study is to modify the blend formulation of a Chlorobutyl rubber compound to improve its damping properties for structural applications. A new rubber composite was created by adding Acrylonitrile Butadiene Rubber (NBR) and Chlorinated Polyethylene (CPE) to Chlorobutyl rubber. The viscoelastic parameters of the cured original CIIR (control sample) and modified CIIR (i.e., CIIR/NBR/CPE) compounds were determined by Dynamic Mechanical Thermal Analysis (DMTA) in tension mode. Subsequently, cyclic shear tests were performed at room temperature and loading frequencies of 0.5, 0.75, 1 and 3 Hz on prototype viscoelastic damper devices fabricated from the rubber blends. The shear force-deformation hysteresis loops of the prototype dampers at shear strains of 0.5, 1.0 and 1.5 revealed that the viscoelastic properties (i.e., shear storage and loss moduli as well as loss factor) of the modified CIIR significantly improved as compared to the original CIIR. The test results demonstrated an increase exceeding 100% and 160% in the shear storage and loss moduli, respectively, of the modified CIIR compared to the reference CIIR.

Daily high traffic loads were reported at junctions, resulting in increased fuel consumption and air pollution at the Lal Shahbaz Qalandar underpass in Lahore. The post-EIA monitoring of Carbon Monoxide (CO), Particulate Matter (PM2.5 / PM10) and noise levels were done near Lal Shahbaz Qalandar Underpass in four different seasons. Pre-EIA (Environment Impact Assessment) monitored levels of CO, PM2.5, and PM10 of the underpass were used for the comparison. Sensor MQ7 was used for monitoring CO levels in the air, and HT608 air quality detector gas checker tester environmental meter was used to monitor particulate matter 2.5 and 10. BeneTech GM1356 digital sound level meter was used for noise level monitoring. For southwest monsoon and winter seasons, CO emissions exceeded the limit for the post-EIA phase (from 7.85 to 8.96 mg/m3). PM2.5 emissions exceeded the normal range both during pre/post-EIA phases. In all seasons, their emissions were constantly increasing (from 40-49 mg/m3) to the pre-EIA phase. Similarly, PM10 emissions exceeded the normal range during pre/post-EIA phases. In all seasons, their emissions have constantly been increasing (from 152-160 g/m3) during the pre-EIA phase. In the pre-EIA phase, the noise level was 81 dB(A), whereas, during the post-EIA phase, the noise level range was from 85-96 dB(A) with a maximum in spring. A significant difference existed for PM2.5 and PM10 between pre-EIA data with post-EIA data. The general trend reveals that carbon monoxide, PM2.5 and PM10 emissions are rising. Poor quality car fuel, unnecessary honking, increased automobile sales, new car manufacturers in Pakistan, very little use of efficient vehicles, and very few public transportation options are the causes of rising air pollution and noise levels following the completion of this underpass's megaproject. The optimal solution to ease traffic congestion and conflicts is to build another underpass/flyover at the next intersection.

Computer-aided educational platforms are of paramount importance as they provide students and engineers with interactive and personalized learning experiences, catering to their individual needs and enhancing their academic growth. This study presents a novel computer-aided educational platform designed by the authors to enhance the understanding of slope stability analysis for young industrial engineers and civil engineering students. The platform is implemented in Matlab, offering a user-friendly graphical interface and a robust framework. It facilitates a comprehensive investigation of landslides, encompassing crucial aspects such as circular slip surfaces and safety considerations based on the Bishop and Ordinary Method of Slices. Furthermore, it enables the determination of minimum safety factors for various methods applied to specific slopes. This paper provides a detailed exposition of each program function, including complete source code, to enhance comprehension of the underlying techniques. To ascertain its accuracy, a slope with given soil properties and geometry were modeled in the Matlab code and the performance of this code was benchmarked against Slide software. It showed only 5 percent error which shows the accuracy of the developed program.

This study analyzes bearing capacity and settlement for a strip footing at the proposed nit Patna Bihta campus site. It uses the Random Finite Element Method (RFEM) based software, which combines viscoplastic finite element analysis with random field theory. The program generates random realizations of the soil domain using local average subdivision method. The average response of the soil domain with variable properties is estimated using Monte-Carlo simulation. The study assumes random variation of soil parameters like cohesion, friction angle, and elastic modulus, while Poisson’s ratio and dilation angle are treated as deterministic variables. The study also considers the cross correlation between cohesion and friction angle. For no cross correlation, theoretical predictions are made for mean and standard deviation of bearing capacity which are verified using Monte Carlo simulation based RFEM results. The probability of bearing capacity failure is also calculated using random finite element analysis and compared with theoretical results. The stochastic analysis of bearing capacity problem indicates that conservative results can be obtained with Prandtl’s bearing capacity formula with consideration correlation length equal to the width of the footing.  In settlement analysis, elastic settlement of strip footing on spatially variable soil is presented. Locally averaged log normally distributed random fields of elastic modulus are generated to conduct probabilistic settlement analysis using RFEM and it is seen that there is very good agreement between the predicted and the actual value of settlement at small and large correlation lengths.  It is concluded that RFEM is a very suitable and efficient tool for investigation of the effect of variation of soil properties in determining the overall mean response for the bearing capacity and settlement behavior.

Of late, three dimensional slope stability analysis has gained popularity among the geotechnical engineers so that the actual response of slope failure, which essentially occurs in 3D, can be captured. However, three dimensional slope failure analysis necessitates the proper consideration of the third/longitudinal dimension of the slope. Three dimensional slope stability analysis can yield erroneous results if inadequate length of the third dimension of the slope is used during analysis. This study employs Bishop’s simplified approach to find the minimum length of a 3D soil slope’s third/longitudinal direction to be considered during analysis. A parametric study compares the findings of 3D and 2D analyses for different geometries, pore pressure ratios and seismic loading for a cohesive-frictional slope. A total of 15 loading cases have been analyzed to study the convergence behavior of the 3D and 2D Factor of Safety (FS) values for slopes with different inclination angles and longitudinal length-to-height (l/h) ratios. The results presented in this study dictate that the longitudinal/third dimension of a 3D slope model should be at least five times the slope’s height for accurate 3D slope analysis. For all loading situations, whether a slope will collapse at the base or toe and the failure mass volumes are estimated. As the base inclination angle increases for a particular slope, the type of failure gradually shifts from base failure to toe failure. The volume of failure mass is seen to follow a decreasing trend with an increase in the slope angle.

This study investigates the potential of using Elephant Grass Straw (EGS) as a reinforcing fibre in Coconut Shell Concrete (CSC) to enhance its mechanical properties. CSC, with a target compressive strength of 20 N/mm², was prepared using coconut shells as coarse aggregate. EGS was incorporated at varying percentages (1-5% by weight of cement). The coconut shell was tested for its properties while the fresh concrete was tested for its workability. The hardened concrete was tested for its density, water absorption capacity, compressive and split tensile strengths. The results indicate that the addition of EGS negatively impacts the workability, compressive and splitting tensile strengths of the concrete specimens. After 28 days of curing, the control sample (without EGS) exhibited the highest compressive strength at 23.1 N/mm² and splitting tensile strength at 1.74 N/mm². Furthermore, a decrease in compressive strength, workability and density was observed, while water absorption capacity increased with EGS inclusion. Overall, this study demonstrates that the incorporation of EGS does not improve the quality of CSC.