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2007 research outputs found
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A Formula for Predicting Primary Settlement of Tropical Highly Organic Soil and Peat in the Field
No full textHighly organic soil and peat are problematic soils due to their low bearing capacity and high compressibility. In tropical regions, the presence of woody material in these soils often affects the stress-compression and time-compression curves in load-increment consolidation tests, leading to unusual shapes. Consequently, conventional inorganic soil theory and the Cα/Ccconcept are inadequate for analyzing their compression behavior. As an alternative, the Gibson and Lo model can be used to obtain compression parameters from single-load consolidation tests. However, this method introduces considerable discrepancies when predicting the primary settlement. To address this issue, this paper proposes a formula for predicting the primary settlement in highly organic soil and peat in the field, especially in tropical regions. Samples were collected from several locations in Indonesia. The formula was constructed from the stress-strain relationship during the primary compression stage, obtained from numerous single-load consolidation tests. Long-term field settlement is predicted by combining this empirical equation for primary settlement with the Gibson and Lo model for secondary settlement. The proposed formula was verified using field soil monitoring data, demonstrating reasonable accuracy in predicting the primary settlement of highly organic soil and peat. Doi: 10.28991/CEJ-2024-010-11-03 Full Text: PD
Assessing the Effect of Geometric Design and Land Use on Roundabouts Using Video Camera
No full textThis study is concerned with assessing the effect of geometric design and land use on roundabouts, which are one of the most widely used traffic calming techniques. It aims to study the speed profiles before, at, and after thirty selected roundabouts in Jordan to develop models for predicting the circulating speed for through movement as a function of the land use of the roundabout, the roundabout geometric characteristics, and the approaching highway free-flow speed. A laser radar gun was used to capture speed data, and geometric characteristics were extracted from video pictures. Various parameters were employed to simulate the circulating speed, including the roundabout diameters, free flow speed, entry deviation angle, approaching highway exit width, circulating roadway width, and entry width. Speed profiles were developed for six roundabout types with different land uses and geometric characteristics. It was found that the roundabout effect on speed reduction extends to 150 m downstream the exit and upstream the entry. It was also discovered that the rate of reduction varies according to the upstream street free flow speed (FFS), with dramatic decreases observed at the last 50 m upstream of the entry. Variability in the speed values around the midpoint of the circulatory roadway was observed, with speed at the exit being higher than that at the entry. Doi: 10.28991/CEJ-2024-010-11-012 Full Text: PD
Assessment of Fluid Forces on Flooded Bridge Superstructures Using the SPH Method
No full textThis paper presents a numerical simulation utilizing the Smoothed Particle Hydrodynamics (SPH) methodology to analyze the impact of water flow on bridge superstructures. The focus of the study is the Canh Nang bridge, which experienced significant damage during a severe flood in Vietnam. The SPH model accounts for flow morphology, velocity fields, and flow pressure around the submerged superstructure, providing insights into areas of high flow pressure and the water resistance coefficient (Cd). By employing modified dynamic boundaries for solid surfaces and the inflow-outflow conditions, the model effectively addresses fluid-bed and fluid-structure interactions. The results highlight elevated flow pressure on specific surface locations of the superstructure, while lower pressures are observed on the bottom surfaces and between adjacent girders. The calculated Cd values are evaluated against those from various bridge design standards, including the Indian code, Eurocode, AS5100, and TCVN 11823. This comparison reveals discrepancies and suggests the potential for refining current design practices. Future research directions include the experimental validation of SPH model results and the exploration of how structural parameters influence superstructure response during flood events. Doi: 10.28991/CEJ-2024-010-12-019 Full Text: PD
Data Mining Approach-Based Damage Identification for Asphalt Pavement Under Natural Disaster Conditions
No full textRoad 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
No full textThis 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
Optimizing Injection Moulding Processes for Structural Components in Construction Management
No full textThe optimization of injection molding processes for structural components is critical in construction management, particularly for enhancing precision, efficiency, and sustainability. However, existing research has not fully addressed the complex interplay of factors that influence this optimization. This study aims to fill this gap by identifying and analyzing five key constructs: Structural Performance, Material Efficiency, Sustainability and Integration, Precision and Consistency, and Design Flexibility. Data were collected from 249 professionals in China using a Likert-scale survey and analyzed through Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), and Structural Equation Modeling (SEM). The results show that Structural Performance is the most significant factor (β = 0.943, p < 0.001), followed by Material Efficiency (β = 0.858, p < 0.001) and Sustainability and Integration (β = 0.772, p < 0.001). The model's predictive relevance, with a Q² value of 0.659, confirms its robustness and accuracy. These findings highlight the need for construction managers to focus on improving Structural Performance and Material Efficiency while integrating sustainability and ensuring precision and flexibility. Optimizing injection molding for construction components is challenging due to complex factors like structural performance, material efficiency, and sustainability. This study develops a novel framework using Structural Equation Modeling to rank these factors, providing insights for cost-effective, high-performance outcomes, and advancing sustainable practices in construction management. Doi: 10.28991/CEJ-2024-010-10-020 Full Text: PD
Influence of Integral Crystalline Waterproofing on Concrete Properties: Dosage Impact and Microstructural Analysis
No full textThe present research study aims to investigate the properties and performance of concrete containing an integral crystalline waterproofing (ICW) admixture, added at an optimal dosage to resist water without compromising structural integrity. To achieve this, an experimental program was conducted on specimens with ICW dosage variations ranging from 0 to 4.8 kg/m2. The impact on water absorption, pulse velocity, and microstructural characteristics was tested and analyzed using XRF and EDS techniques. The findings reveal that increasing the dosage decreases water absorption by approximately 43% at maximum dosage compared with the control. A 41% increase in pulse velocity indicates a denser concrete matrix. The principle of optimization is highlighted, as an overdose of ICW generates a non-structural crystalline gel at the bottom of the specimens. The optimum dosage range for ICW to improve water resistance without adverse effects on structural performance was determined to be 3.2 to 4.0 kg/m2. This research introduces a novel approach by evaluating the comprehensive performance of concrete in relation to ICW dosage, providing valuable insights into the practical application of ICW admixture to enhance concrete quality and durability. Doi: 10.28991/CEJ-2024-010-10-02 Full Text: PD
Seismic Performance Assessment of Sustainable Shelter Building Using Microtremor Method
No full textThe increasing intensity of earthquakes in West Sumatra could trigger megathrust earthquakes and tsunamis at the inter-plate in the Mentawai Islands. Building assessments are necessary to determine their vulnerability to predicted earthquakes. The target is a four-story building that serves as an education building and vertical evacuation. This research proposes a complete vulnerability assessment method using single microtremor observations, and the results are used to determine seismic building performance. The natural frequency is derived from the spectral analysis of the horizontal components (NS and EW) for each level, and we considered the largest earthquake peak ground motion (PGA) in this region to be the September 30, 2009, Padang earthquake (PGA 380 gals as ground motion input). We calculated the resonance index, seismic vulnerability index, and damping ratio. The results show that the resonance index of the structure is less than 1, the vulnerability index of the UNP Faculty of Economics building ɤ > (1/100-1/200) and is 1/234 to 1/699 for the x direction and 1/207 to 1/709 for the y direction; the average damping ratio is <5% for both directions (x, y) and RDM and FSR relationship is 0.78 and 0.69 for x and y respectively. The overall findings indicate that the structural response of the evaluated buildings falls within the 'slight' damage category during seismic events. Doi: 10.28991/CEJ-2024-010-11-06 Full Text: PD
Utilization of Sand Cushion for Stabilization of Peat Layer Considering Dynamic Response of Compaction
No full textSoft peat soils are located in many zones and at a given depth all over the world and are characterized by their low shear strength and high settlement. It can also cause progressive failure of roads, embankments, and foundations. Sand cushioning is the most beneficial technique used to relieve the stress transmitted to the peat layer to mitigate any deformation and shear failure. In this research, a field study of a road with a soft peat layer located at a depth 4m below the ground surface is carried out. The plate load test is conducted on three cases over the peat layer using sand cushions with and without reinforcement. The results were compared with plate footing on the surface of the road without stabilization. The field tests of the improved technique were verified and deeply analyzed using the numerical program Plaxis. The finite element analysis mainly sheds light on the simulation of the dynamic response that represents the compaction of the sand cushion over the peat layer. A series of numerical models has been done considering the effect of repeated load compaction on the adopted sand cushions with and without reinforcement. The numerical analysis is directed to show the effect of repeated loads of compaction equipment that were used on decreasing the stress over the peat layer. The results showed that the composite compacted cushion with both a higher number of cycles and stress has a great effect on relieving the stresses transmitted to the face of the peat. As a result, the footing capacity is increased with less deformation. Doi: 10.28991/CEJ-2024-010-04-011 Full Text: PD
Behavior of Fire-damaged RC Beams After Strengthening with Various Techniques
No full textHigh temperatures during a fire can significantly degrade the structural capacity of concrete. However, in many cases, it is possible to restore and strengthen fire-damaged concrete rather than completely rebuild damaged structures. The study considered two types of concrete (normal 25 MPa and high-strength 65 MPa) with two types of strengthening techniques: carbon-fiber-reinforced polymers (CFRP) sheets with different thicknesses of 1.5 and 2.5 mm and slurry-infiltrated fibrous concrete (SIFCON) jacketing with different fiber sizes of 20 and 30 mm. The numerical simulations and analyses were conducted to capture the complex behavior of fire-damaged concrete members (beams). A fire-damaged concrete beam subjected to an extreme or critical fire Exposure time (2 hours) was evaluated and modified using a finite element simulation approach. The simulation process included three stages: the first, subjecting the concrete beam to thermal loading; the second, reflecting the fire distribution map to another model of applying mechanical loading; and the third, involving the application of strengthening to the damaged model. The results showed that the strengthening using CFRP with a thickness of 2.5 improved the load-carrying capacity compared with SIFCON in both types of concrete. 200% improvement for the normal-strength concrete beam and a 136% improvement for the high-strength concrete beam, compared to the damaged beams. Doi: 10.28991/CEJ-2024-010-01-012 Full Text: PD