Civil Engineering Journal
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2007 research outputs found
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Numerical Analysis of Ground Motion Topographic and Geological Effect: A Case Study of MOXI Platform
No full textThe ground motion amplification effect influenced by diverse topographic and geological conditions was investigated to enhance the seismic design standards for mountain structures. A comprehensive series of two-dimensional and three-dimensional numerical simulations was conducted. These simulations utilized idealized and real-world topographic models, meticulously considering various critical parameters, such as platform height, width, slope, surface angle, and soil properties. The results reveal that topographic and geological factors both significantly impact the ground motion amplification effect, with the maximum amplification factors frequently surpassing those stipulated by the current Chinese seismic code. Based on these findings, a refined and modified formula was developed for calculating the ground motion amplification factor that integrates the influences of height, width, slope, and geological conditions. The validity and feasibility of this modified formula were substantiated thoroughly through detailed comparisons between the actual observed values and the suggested values, demonstrating its potential to improve the safety and reliability of seismic design in mountainous regions substantially
Evaluating the Role of Polymer Concrete in Enhancing Long-Term Performance and Reducing Early Age Cracking
No full textThis study evaluates the potential of polymer concrete (PC) to reduce early-age cracking and improve long-term durability compared to traditional Portland cement concrete (PCC). It investigates the effect of varying polymer-to-aggregate ratios (5%-20%) on mechanical properties, early-age cracking, and durability under extreme environmental conditions, including freeze-thaw cycles, high temperatures, and chemical exposure. Experimental tests were conducted to measure compressive strength, flexural strength, fracture toughness, and durability of PC under accelerated aging conditions. The methodology involved mixing epoxy resin with selected aggregates to create different PC formulations. Tests such as restrained shrinkage, freeze-thaw, sulfuric acid immersion, and high-temperature exposure simulated real-world conditions. Results showed that PC with 15%-20% polymer content reduced early-age cracking by up to 56%, increased compressive strength by 28%, and exhibited superior resistance to freeze-thaw cycles and chemical degradation compared to PCC. The main contribution of this study is a comprehensive comparison between PC and PCC under accelerated aging, providing insights into the optimal polymer-to-aggregate ratio for maximizing performance and durability. These findings underscore the potential of polymer concrete as a durable, long-lasting material for high-performance infrastructure, especially in harsh environments. The research suggests that PC could extend the service life of concrete structures, lower maintenance costs, and offer a more sustainable alternative to traditional concrete
The Influence of the Fine Earth Composition of the Soil Mixture on the Parameters of Its Filtration, Moisture Content, and Density
No full textThe article presents the results of laboratory studies on the patterns of change in the filtration coefficient of the fine-grained component (fine earth) of the soil mixture from a number of influencing factors. The study was conducted to assess the impact of the fine earth fractional composition of a soil mixture on its filtration parameters and density-moisture state. The experiments were conducted using a compression device, the use of which is regulated by the standard of the Republic of Kazakhstan. One hundred and twenty-six fine earth samples were tested, containing 50 to 75% (by weight) of various fractions with particle sizes smaller than 5 mm. An analysis of the test results revealed that for large fractions (with particle sizes of 5 mm or less, but more than 1 mm), the filtration coefficient of fine earth increases as the weight content of fractions in it increases (from 50 to 75%), while for small fractions (with particle sizes of 1 mm or less), it decreases. It was determined that similar patterns are characteristic of the increase in moisture content and increase in the density of fine earth, which occur when water is filtered through it. The scientific novelty of the research lies in the fact that, based on the identified patterns, correlation dependencies were established between the filtration coefficient and the weight content of various fractions, as well as the increase in moisture content and the increase in the density of fine earth. Correlation dependencies of the filtration coefficient on the weight content of various fractions, as well as on the increase in moisture content and increase in the density of fine earth, were established. Based on the established relationships, formulas were developed for predicting the filtration coefficient, moisture content, and density of fine earth, which adds practical value to the research. These formulas are recommended for use in selecting optimal fine earth compositions for soil mixtures used in dam construction
Stability Analysis of Dike Pond Due to Pore-Water Pressure Changes
No full textThe Brigif retention pond not only serves to temporarily store rainwater for groundwater reserving but also reduces the risk of flooding in the Southern Jakarta area. Research was purposed to study two critical conditions of a dike made from clayey material from before to after water impounding stages correlating with its stability. The research will investigate pore-water pressure (u) parameter changes at any stage in both conditions. The parameter of (u) can be predicted (upre) using the laboratory consolidation or oedometer test and measured (uact) completely with hydrostatic pressure (u0) directly in the field. Actual measurements using a piezometer were also conducted on the body of the dike. The prediction analysis used the self-developed program and conventional geotechnical software. The critical peak depth of (u) was found at 3.0 to 4.0 m. The actual settlement potential values reached -0.10 to -1.42 m and matched the prediction result. Safety factor (SF) was around 2.0 to 4.0, or in stable condition. Research results found that the magnitude parameter of (u) could be influenced by groundwater flow and porosity or void ratio fluctuations. The consolidation process also would affect the physical soil pore, contributing to the change of (SF) the dike pond
Data-Driven Approach to Predict Fire-Resistance Ratings of Timber Columns
No full textThis study aims to determine whether a data-driven-based approach provides more accurate predictions of timber fire-resistance ratings (FRR) compared to conventional empirical methods. To achieve this, a machine learning framework based on the Deep Belief Network (DBN) was employed. A comprehensive database collected from previously published reports was used to train and validate the DBN model. The model’s predictive performance was benchmarked against traditional empirical equations derived from mechanics-based methods. The comparison demonstrated that the DBN model provided superior accuracy in predicting fire-resistance ratings. Model evaluation was further conducted using the Coefficient of Determination (R²) and Root Mean Squared Error (RMSE), confirming the robustness of the proposed approach. In addition, a parametric analysis was performed to assess the influence of input variables on the output. Results indicated that induced load (IDL) and breadth (BRH) were the most influential parameters, whereas ultimate strength (ULS) and elasticity modulus (ELM) had relatively minor effects. This study highlights the potential of advanced machine learning techniques, particularly DBN, to enhance predictive accuracy in structural fire engineering, offering a significant improvement over conventional calculation methods
The Use of Electronic Initiation Systems for Wall Control Blasting at an Open Pit Mine
No full textThis study investigates the effectiveness of electronic initiation systems (EIS) for wall control blasting in open-pit mining, with a specific focus on their influence on ground vibrations and rock fragmentation. The primary objective of the study is to evaluate whether EIS can achieve comparable or superior results in fragmentation quality while reducing seismic impact compared to non-electric initiation systems (NEIS). Experiments were conducted at an open-pit gold mine. During the experiments, EIS and NEIS were used. There was assessed seismicity of each blast during the experiments. Peak Particle Velocity (PPV) was measured at multiple points near the pit benches, and fragmentation of the blasted rock mass was analyzed through visual inspection and image analysis techniques. A statistical evaluation of the collected data revealed that EIS provided similar fragmentation outcomes while significantly reducing PPV values. Due to the ability to precisely time blasts and allow for optimized delay sequences and energy distribution, EIS can reduce blast vibrations. These findings suggest that EIS is a viable and efficient solution for wall control blasting, particularly in cases where pre-splitting or other conventional techniques cannot be applied due to geological or operational conditions. In this study, for the first time,the PPV was measured at the closest distance (6.57 m to the blasted block). The authors tried to find out the combination of two controversial outcomes of blasting work, rock fragmentation and ground vibrations, in this study
Sustainable Utilization of Recycled Concrete Powder as Sand Replacement in Cement Mortar Production: Impact of Sand-Cement Ratio
No full textThe construction industry is becoming more interested in recycled concrete sand obtained from concrete waste due to the urgent need for environmentally friendly building materials. This research investigates the mechanical along durability properties of cement mortars made of recycled concrete sand as a full replacement of natural sand. With a fixed water-to-cement ratio of 0.48, five values of sand-to-cement ratio, including 0.50, 1.00, 1.50, 2.00, and 2.75, were used to prepare different mortar mixes to investigate its effect on the behavior of the mortar. Results indicate a decline in workability with an increasing sand-to-cement ratio, with flow values ranging from 137% at a sand-to-cement ratio of 0.5 to 58% at a sand-to-cement ratio of 2.75. The highest compressive strength of 40.3 MPa was observed in the mix with a sand-to-cement ratio of 0.5 at 28 days, while the mix with a sand-to-cement ratio of 2.75 exhibited the lowest strength at 29.8 MPa, attributed to higher internal porosity. The mix of sand to cement of 1.5 demonstrated a balanced performance, achieving a compressive strength of 29.8 MPa and a flow value of 110 ± 5%, making it suitable for practical applications. Water absorption increased with higher sand-to-cement ratios, consistent with increased void content. Microstructural analysis revealed the presence of residual cementitious phases such as belite and calcium hydroxide in recycled concrete sand, contributing to secondary hydration and influencing durability characteristics. Although mortars containing natural sand outperformed recycled concrete sand-based mixtures in strength and workability, recycled concrete sand mortars met the required performance criteria for building, plastering, and non-structural applications. This study supports the viability of recycled concrete sand as a sustainable alternative to natural sand, contributing to resource conservation and waste reduction in the construction industry
Evaluating Rock Mass Quality and Critical Depth for Rockburst Hazard in Deep Mines
No full textThis study investigates the geomechanical behavior of the rock mass at the Zhayssan mine in Kazakhstan, focusing on improving the safety of deep mining operations. The objective is to forecast the working strength of rock masses and assess the associated rockburst risks, especially given the limited existing data on the mechanical properties of the site’s rocks. To achieve this, we conducted comprehensive laboratory tests to determine rock strength characteristics, brittleness, and elastic energy accumulation capacity. We analyzed these data using the Rock Quality Designation (RQD) indicator and constructed a simplified geomechanical model of the deposit. Our findings reveal that rock mass quality improves with depth, as indicated by higher RQD values and reduced fracturing intensity; however, this improvement coincides with an increased risk of dynamic rock pressure events, particularly beyond the analytically estimated critical depth of approximately 400 meters. The study’s novelty lies in its integration of local testing data with comparative regional data, allowing for a more robust preliminary risk assessment despite limited local measurements. As promising directions, the paper suggests further laboratory and field research to refine methods for forecasting the strength and stability of mine workings
Inelastic Response of Fixed and Flexible Foundation of Structure Under Seismic Excitations Generated Deterministically
No full textResearchers performed inelastic dynamic analysis on simulated ground motion while accounting for foundation flexibility in the specific area of Yogyakarta. The closest fault source to the building site is the Opak Fault, situated 2.1 kilometers from the structure. The closeness to the fault source, which suggests an exceedingly high earthquake magnitude, prompted the use of deterministic analysis. Deterministic analysis used five Ground Motion Prediction Equations (GMPEs): Campbell-Bozorgnia (2006), Sadigh et al. (1997), Ciao-Youngs (2008), Zhao et al. (2006), and Kanno et al. (2006), while the flexibility of the foundation was evaluated using the formula proposed by Novak (1989). The analysis results show that the vibration period that occurs on the flexible support is 2.8 seconds, while on the fixed support it is 2.4 seconds. Deflections and drift ratios in structures with fixed support and high-frequency content are greater, but in beam curvature the results show the opposite, namely, low-frequency content produces larger curvature values. The damage index on the fixed support and high-frequency content is greater than the others. Not much research has looked into the results of inelastic response analysis that includes hysteretic loop outputs and damage indices, making this a new area of study
Impact of Water Quality and Sediments on the Riparian Vegetation of Andean Lake
No full textThis study evaluates the quality of water and sediments in a high-altitude Andean lake designated as a RAMSAR wetland of international ecological importance called Guamuéz Lake (Laguna de la Cocha). The analysis focuses on their effects on riparian vegetation, particularly on Schoenoplectus californicus (Bulrush), a keystone species in the lacustrine ecosystem. Water and sediment samples were collected from areas under varying levels of anthropogenic pressure, including zones with and without visible degradation. Results indicate that agricultural runoff, aquaculture, and domestic wastewater discharges are major drivers of spatial and seasonal variability in water quality. Elevated biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) were observed during the rainy season, suggesting increased organic matter input. Sediment analyses showed that impacted areas had higher concentrations of metals such as iron and manganese and significantly elevated microbial loads. Microbiological analysis of sediments revealed a 440% increase in total microbial colonies at impacted sites compared to unaffected ones, with fecal coliforms (FC) and total coliforms (TC) increasing by 191% and 513%, respectively. This suggests that wastewater contamination promotes anaerobic conditions detrimental to S. californicus root systems, possibly contributing to vegetation dieback. The findings underscore the importance of including sediment quality assessments in aquatic ecosystem monitoring, as key indicators of riparian vegetation decline may not be evident through water analysis alone. These results call for integrated and sustainable watershed management practices to mitigate human impact and preserve the ecological integrity of this internationally recognized wetland system