2031 research outputs found
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Influence of Temperature on the Viscoelastic Behavior and Durability of Flexible Pavements
Get PDFThis study meticulously examines the impact of temperature variations on the viscoelastic characteristics of flexible pavements composed of mineral aggregates and bituminous binders. The primary objective is to understand how temperature fluctuations affect the structure and durability of these pavements, designed to withstand traffic loads while absorbing stresses induced by weather conditions. The methodology involves a thorough analysis of a range of temperatures from T1 to T4, assessing their effects on road rutting and the longevity of pavement infrastructure. Through a detailed analytical approach, the research investigates the viscoelastic behavior of bituminous mixes, which display viscous and elastic properties that change with temperature. The findings reveal significant correlations between temperature variations and the performance of flexible pavements, offering insights into their structural resilience and durability under different climatic conditions. This research introduces a novel approach to managing flexible pavement infrastructure by enhancing our understanding of the temperature-induced viscoelastic response. The improvement lies in the precise quantification of temperature impacts, which can inform better maintenance and design strategies for flexible pavements. Ultimately, this leads to more resilient and long-lasting road surfaces, addressing the critical need for durable infrastructure in changing weather patterns. Doi: 10.28991/CEJ-2024-010-07-06 Full Text: PD
Flexural Performance of Beams Strengthened with FRP Laminates and Alternative U-Wrap Anchors
Get PDFPremature debonding is identified as the main failure mode in reinforced concrete (RC) beams strengthened with externally bonded Fiber-Reinforced Polymer (FRP) laminates. This issue leads to the underutilization of FRP materials and needs to be addressed. Research has shown that end anchorage systems can effectively delay/mitigate delamination failures and enhance the performance of strengthened beams. FRP U-wraps are an effective means to prevent debonding failure; however, as open-form anchors, U-wraps cannot always guarantee complete resistance to debonding failures. This study proposes an alternative U-wrapping technique where the ends of the U-wraps are flared and inserted into the concrete substrate. The feasibility and effectiveness of this technique were studied by comparing it with conventional U-wraps. The experimental phase involved testing seven RC beams, each measuring 1.96í—0.15í—0.3 meters, under four-point bending. The results showed that the anchorage technique improved beam performance in terms of load-deflection behavior, failure modes, ductility, and FRP strain. Additionally, finite element simulations were conducted using Abaqus software to assess the effectiveness of the alternative U-wrap scheme. These models incorporated various nonlinear material constitutive laws, including cohesive zone modeling to replicate debonding failures at the CFRP-concrete interface. The numerical predictions were found to be in good agreement with the experimental test data. Doi: 10.28991/CEJ-2024-010-08-01 Full Text: PD
Flexural Performance of a New Composite Double PSSDB Slab System Filled with Recycled Concrete
Get PDFThis study investigated the flexural performance of a composite floor system utilizing a profile steel sheet dry board (PSSDB) that was enhanced by adding an additional layer of profile steel sheet (PSS) and infilled with both normal and recycled concrete materials. This improved system is referred to as the double-profile steel sheet dry board (DPSSDB) system. The new DPSSDB concept was proposed to reduce fabrication costs, overall weight, and the depth of the composite floor system compared to traditional composite beam-slab systems. To assess the impact of the additional PSS layer, ten full-scale specimens of both PSSDB and DPSSDB were subjected to four-point static load tests. Additionally, the study investigated the use of lightweight recycled aggregates such as crumb rubber and expanded polystyrene as partial replacements for the aggregates in the infill concrete. The results demonstrated that the DPSSDB system exhibited a 112–170% increase in bending capacity compared to the PSSDB specimens. Partial replacement of concrete aggregates with lightweight recycled materials up to 50% had only a marginal effect on the bending behavior of both PSSDB and DPSSDB specimens compared to those filled with normal concrete. However, replacing 75% of the aggregate with recycled materials led to a 27% reduction in the flexural bending capacity of the DPSSDB specimens compared to those infilled with normal concrete. Additionally, a new method (theoretical equation) was developed to predict the ultimate moment strength (flexural) of the novel DPSSDB composite slab system, which aligned well with the experimental results, achieving a deviation percentage of 0.81% and a mean value of 0.965a. Doi: 10.28991/CEJ-2024-010-12-03 Full Text: PD
The Performance of Geosynthetic Reinforcement Road Pavement Over Expansive Soil Subgrade
Get PDFOne of the problems faced in infrastructure development, especially roads, is problematic soils, including expansive soils, which are distributed around 20% of national road construction in Indonesia. Geosynthetics are reinforcement materials that can be used to overcome problematic soils. The study aimed to determine the behavior of expansive soil with geosynthetic reinforcement against swelling potential and swelling pressure in the wetting cycle. The research utilized an experimental approach involving three test concepts. The first was a control test without reinforcement. The second included a combination of geogrid, geotextile, and geomembrane layers, while the third utilized an H2Rx reinforcement layer. Analysis was carried out on the development potential and pressure; the test was carried out for 57 days using displacement sensors and pressure sensors, and data recording was carried out every 5 seconds using a computer. The findings from the results of this study indicated that the presence of reinforcement using a geosynthetic reinforcement layer can overcome the behavior that occurs in expansive soils with swelling potential and swelling pressure. The novelty of this research is the inclusion of a geosynthetic reinforcement layer on expansive soil combined with a drainage layer in the pavement subgrade. Doi: 10.28991/CEJ-2024-010-12-020 Full Text: PD
An Investigation of Dynamic Soil-Structure Interaction on the Seismic Behavior of RC Base-Isolated Buildings
Get PDFSoil-structure interaction (SSI) can significantly influence earthquake responses in base-isolated (BI) buildings, yet it is often overlooked in practice due to the high computational demands of complex analyses. This study investigates SSI effects on reinforced concrete (RC) base-isolated buildings, idealizing SSI with a cone model. Three BI building models of varying heights and soil characteristics were analyzed using modal and nonlinear time history analysis. The base isolation system incorporated elastic sliding bearings, lead rubber bearings, natural rubber bearings, and oil dampers. The SSI model was idealized considering hard, medium, and soft soils. To simulate earthquake input, three artificial ground motions with different phase characteristics were generated to match the design response spectrum according to the Japanese code. The seismic responses of the base-isolated building models with SSI were compared to those of models without SSI. Modal analysis showed that the natural period increased with softer soil profiles. In the first and second modes, the natural period lengthened as the building's aspect ratio increased. Conversely, in the higher modes with a rocking pattern, the building with the lowest aspect ratio exhibited the longest natural period. Overall, implementing SSI generally reduced seismic responses, notably lowering story drift, acceleration, and force, particularly for buildings on soft soil. However, the SSI effect significantly increased the base rotation angle in high aspect ratio buildings on soft and medium soils. These findings indicate that including SSI in analysis is essential for more realistic seismic response predictions, especially for tall, slender base-isolated buildings. Doi: 10.28991/CEJ-2024-010-11-01 Full Text: PD
Data Mining Approach-Based Damage Identification for Asphalt Pavement Under Natural Disaster Conditions
Get PDFRoad performance can also decline due to natural disasters such as earthquakes, often in Indonesia. Given the high risk of natural disasters in Indonesia, it is important to consider their impact. Therefore, it is necessary to prepare for road rehabilitation and reconstruction quickly and accurately. This research aims to identify potential factors causing road damage by developing an approach to obtain predictions of road damage levels due to natural disasters by utilizing the availability of historical data, developing a decision support system to rehabilitate and reconstruct roads after disasters, and developing a road damage model due to earthquakes using data mining. The data was used to assess the condition of the national road pavement in Central Sulawesi and identified the disaster events as earthquakes that originated from the USGS. Data processing uses a data mining (DM) approach, which includes three models. The results found that the SVM modeling with the DM approach had a high accuracy rate of 0.91 ± 0.01, RMSE 0.70 ± 0.02, and MAD 0.42 ± 0.01. SVM achieves the highest accuracy after 20 runs. The best hyperparameters to accomplish a fit SVM model are ϵ = 0.07 ± 0.01 and γ = 0.05 ± 0.00. Meanwhile, for ANN, the hyperparameters are H = 3 ± 1. The earthquake's magnitude (27%) and depth (24%) contribute to road damage. Doi: 10.28991/CEJ-2024-010-12-015 Full Text: PD
Utilizing Recycled Rubber and Municipal Waste Incineration Fly Ash in Cement-Stabilized Clayey Soils
Get PDFThis study explores an innovative approach combining municipal solid waste incinerator fly ash (MSWIFA), cement, and recycled rubber to enhance soil properties. The research fills a research gap by exploring the synergistic effects of these materials, striving to strike a balance between strength and flexibility in soil stabilization. A total of 123 tests, comprising Proctor compaction and unconfined compression tests, were performed on clayey soil samples treated with varying stabilizer proportions: 10%, 20%, and 30% MSWIFA; 10%, 15%, and 20% cement; and 0%, 5%, and 10% rubber by dry weight. The tests revealed that the ideal blend of 5% rubber, 10% MSWIFA, and 20% cement resulted in a notable 294% increase in unconfined compressive strength and a significant enhancement in soil ductility, presenting a stark contrast to traditional cement-stabilized soils recognized for their brittleness and limited flexibility. This approach not only enhances soil characteristics but also promotes environmental sustainability by utilizing waste materials in the stabilization process. Doi: 10.28991/CEJ-2024-010-11-017 Full Text: PD
Investigating Mechanical Properties of Metakaolin-Based Geopolymer Concrete Optimized with Wastepaper Ash and Plastic Granules
Get PDFThis study develops an environmentally friendly geopolymer concrete (GPC) using wastepaper ash (WPA) and high-density polyethylene (HDPE) granules, addressing environmental challenges such as wastepaper and HDPE disposal and CO2emissions from cement production. WPA was produced by incinerating wastepaper at 550 °C for one hour and used as a partial replacement for MK in ratios of 10%, 20%, 30%, 40%, 50%, and 100%, while HDPE granules replaced river sand in ratios from 1% to 5%. The results showed that the use of 30% WPA resulted in a compressive strength (CS) of 35.38 MPa, which was significantly higher than the control sample's CS of 31.62 MPa. The use of 30% WPA increased slump due to lower water demand. The combination of 3% HDPE and 30% WPA further enhanced the mechanical properties, resulting in a CS of 36.54 MPa, representing a 15.5% increase over the control. However, the addition of 3% HDPE and 30% WPA reduced the slump, attributed to the increased friction from the HDPE granules. Advanced analyses, including SEM, EDX, and XRD, confirmed a refined pore structure and increased geopolymerization in the treated GPC. It is novel to optimize WPA and HDPE as waste products in the production of MK-based GPC. Doi: 10.28991/CEJ-SP2024-010-011 Full Text: PD
Comparison of Multi-Objective Metaheuristics for Discrete Optimization of Steel Trusses Using Direct Analysis
Get PDFThis study enriches structural optimization research using direct analysis for steel truss structures, which is often hampered by high computational demands. The main objective of this work is to evaluate multi-objective optimization algorithms in truss sizing optimization with discrete variables, focusing on minimizing total mass and controlling inter-story drift under multiple load combinations. Five leading multi-objective metaheuristic algorithms were assessed: SPEA2, GDE3, NSGA2, MOEA/D, and the novel MOEA/D-EpDE, which uniquely combines MOEA/D with Dynamical Resource Allocation and pbest Differential Evolution. Four performance indicators, such as Generational Distance (GD), GD Plus (GD+), Inverted GD+ (IGD+), and Hypervolume (HV), were utilized. Findings from four truss optimization problems revealed that all considered algorithms located feasible optimal solutions, but MOEA/D-EpDE excelled, consistently securing the lowest GD, GD+, IGD+, and anchor point values, along with the highest HV values in most scenarios. This indicates its superior capability in addressing the problem efficiently. NSGA2 and MOEA/D also performed well, outperforming GDE3 and SPEA2. This study is pioneering in its application of these algorithms to steel truss optimization via direct analysis, highlighting the potential for advanced computational techniques in structural engineering. Doi: 10.28991/CEJ-2024-010-12-07 Full Text: PD
Unified AI-Based Predictive Models for the Ultimate Capacity of Multi-Planar Gapped KK Steel Pipe Joints
Get PDFThe multi-planar steel pipe joints are widely used in communication towers, industrial structures, and offshore platforms. The current design formulas consider this joint as a uniplanar joint and account for the multi-planar effect using empirical correction factors. Recent studies deal with this multi-planar joint as a 3D joint but considering certain loading conditions. Hence, the aim of this research is to develop more general AI-based predictive models for the ultimate capacity of multi-planar gapped KK steel pipe joints, considering both symmetric and asymmetric loading conditions. Three AI techniques were applied to a database of previously published works. These techniques are "Genetic Programming” (GP), "Artificial Neural Network” (ANN), and "Evolutionary Polynomial Regression” (EPR). The prediction accuracies of the developed AI models were compared against two previously published formulas. The results indicated that the developed AI models are much more accurate than the previously published formulas. Also, the results showed that both the ANN and EPR models have almost the same level of accuracy (about 92%), but the EPR model has the advantage of presenting a closed-form equation that could be implemented either manually or using software. Doi: 10.28991/CEJ-SP2024-010-07 Full Text: PD