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Extreme Event-based Rainfall-Runoff Simulation Utilizing GIS Techniques in Irawan Watershed, Palawan, Philippines
No full textRiver flow assessments and ecologically sustainable water management plans are now possible due to the advancement of sophisticated computer models. The US Army Corps of Engineers developed the HEC-HMS model, which can be used for various hydrological simulations. Rainfall-runoff modeling aids in estimating peak flows, which is critical for water resource management planning. On December 18, 2017, a heavy rainfall event in the ungauged Irawan basin in Puerto Princesa City, Palawan, Philippines, was simulated to determine the peak flow and amount of water. The current research aims to construct a rainfall-runoff simulation model. A specific hyetograph is used to make the hydrographs for the basin. This study utilizes ArcGIS and QGIS, which perform the geospatial analysis and provide the HEC-HMS model's hydrologic modeling inputs. The hydrological parameters were determined using soil type, land use, and land cover maps. Incorporating SCS loss, Clark unit hydrograph, and Muskingum flow routing, HEC-HMS was employed in the rainfall-runoff simulation. Rainfall data corresponding to the recorded streamflow was used to calibrate and validate the parameters. Several performance metrics, including Nash-Sutcliffe efficiency (NSE) and Percentage Bias (PBIAS), were utilized to evaluate the overall effectiveness of the system. An effective decision-making and warning system can be implemented using the developed model. Doi: 10.28991/CEJ-2023-09-01-017 Full Text: PD
Structural Behavior of Steel Reinforced Concrete Joint Under Flexural Loads
No full textThis research investigates the behavior of RC beam column joints reinforced with steel sections. The study deals with the strengthening of RC joints by different steel sections. The investigation included a theoretical analysis through a performing of simulation of beam-column joints laced with steel sections by using FEA. Implementation of the parametric study included reinforcing the concrete beam with steel sections in many configurations. Shapes and length were the most variables in this study, and many shapes were used, such as I-section, box section, and plates, beside the concrete compressive strength variable. The most recent study revealed the possibility of the method to enhance the efficiency of the joint in resisting the loads while the offering many additional features such as higher ductility, stiffness, and energy absorption. The results showed that strengthening by the steel section enhanced the flexural strength of the joint, but these enhancements were to a certain limit due to the concrete strength limitation. The ultimate strength enhancement was 49%, which is considered a good index for the joint efficiency. The use of compressive strength in small amounts led to the enhancements being limited due to the weakness of the concrete. Strengthening the flexural side of the beam by adding a steel section requires stronger concrete to provide more contribution for the steel section to resist more flexural loads. The increase in the compressive strength of the concrete made the improvements reach their peaks. Strengthening by I-shaped and box steel sections showed that the enhancement due to the existence of the I section was greater than that of the box one. Doi: 10.28991/CEJ-2023-09-03-015 Full Text: PD
Optimization of Integrated Reservoir for Supporting the Raw Water Supply
No full textThis research intends to analyze the optimal operation pattern for fulfilling the raw water demand, and it is conducted in the integrated cascade reservoir of Duriangkang-Muka Kuning, Batam City, Indonesia. However, Batam City is the economic center of the Riau Islands and absolutely needs enough raw water supplies to support its development. The need for raw water in Batam City is predicted to reach about 6,630.29 l/s in 2025. Due to the population growth that is estimated to reach about 1.8 million people in 2025 and the plan of Batam City development as an industry and tourism center, Batam City is faced with the condition that reservoir management becomes a very important thing for supporting the continuity of water supply. The methodology consists of collecting the supporting data, such as inflow, reservoir capacity curve, and data on water needs; then building the optimization model by determining the objective function and constraints of the integrated reservoir; and carrying out the optimization model by using linear programming and simulation models for the integrated reservoir operation. The result presents optimal reservoir operation of the integrated Duriangkang-Muka Kuning reservoirs. The reservoir operation consists of the boundary curve of upper and lower normal operation, the outflow for fulfilling the water need, and the rule of supply pumping from Duriangkang reservoir to Muka Kuning reservoir. It is hoped that the result can be used as a reference in operating the two reservoirs to fulfill the water needs of the Batam City population. Doi: 10.28991/CEJ-2023-09-04-07 Full Text: PD
Performance Evaluation of Fiber-reinforced Ferroconcrete using Response Surface Methodology
No full textFibre-reinforced ferroconcrete is a new-generation type of concrete that has been found to have adequate performance. Global emissions of CO2 as a result of concrete production have damaged the earth's atmosphere. These emissions, together with construction waste, such as ceramic powder and aluminium waste, are considered one of the most harmful wastes to the environment, eventually leading to pollution. In this study, the fibre-reinforced ferroconcrete (FRFC) contained waste aluminium fibre, cement, ceramic waste powder, corrugated wire mesh, and fine and coarse aggregate. The cement content in the concrete mix was partially replaced with Ceramic Powder (CP) in proportions of 0%, 10%, and 20%, while the Aluminum Fibers (AF) were added in proportions 0, 1, and 2% to the concrete mix. The variation of ceramic powder and aluminium fibres was done using the central composite design of Response Surface Methodology (RSM) to create experimental design points meant to improve the fibre-reinforced ferroconcrete's mechanical performance. The results conclude that the mechanical performance of the FRFC was slightly improved more than conventional concrete, where at 20% replacement of ceramic powder and 1% addition of aluminium fibre to the concrete mix. There was more compressive, flexural, and split tensile strength increase than conventional concrete, with control concrete having strengths of 13.060, 5.720, and 3.110 N/mm2 and ferroconcrete 15.88, 6.68, and 3.83 N/mm2 respectively. This was further confirmed with microstructural images. The RSM model, with parameters such as; contour plots, analysis of variance, and optimisation, was used to effectively predict and optimise the responses of the ferroconcrete based on the independent variables (Aluminum fibre and Ceramic Powder) considered. The results of the predicted data show a straight-line linear progression as the coefficient of determination (R2) tends to 1, indicating that the RSM model is suitable for predicting the response of the variables on the FRFC. Doi: 10.28991/CEJ-2023-09-04-014 Full Text: PD
Flood Sedimentology for Future Floods Mitigation in North Luwu, Sulawesi, Indonesia
No full textA sedimentological study after the flash floods that hit North Luwu on July 13, 2020, has been carried out on three affected rivers, namely the Masamba River, the Radda River, and the Binuang River. The study aims to determine the sedimentological impact of the 2020 flash flood disaster, including sedimentation rate, annual bedload sediment volume, and total sediments, which will be used as a reference for future mitigation consideration. The study is based on fieldwork for data collection and laboratory analysis. The results of field measurements and laboratory analysis are then processed by calculating the sedimentation rate at the annual discharge, the bedload sediment volume, and the total estimated sediment accumulated by the flash flood. Sedimentation rate analysis was performed using the Ackers-White formula, and flood delineation was processed using HEC-RAS software. The climatological data from the climatology station at Andi Djemma Airport were used to calculate the river discharge. It is estimated that the volume of bedload sediment in the Binuang River is 16,194,168 m3/year, that of the Masamba River is 7,852,061 m3/year, and that of the Radda River is 4,003,011 m3/year. The volume of sediment brought by flash flood sedimentation in the Radda River is 9,141,608.39 m3, while that in the Masamba River is 55,131,761.29 m3, and that in the Binuang River is 136,838,603.61 m3. The total estimated sedimentation generated by the flash flood on the three rivers on July 13, 2020, is 222,476,966 m3. Based on the study, zonation for vulnerability levels is designed for a future mitigation scheme. The zonation can be classified into three zones: 1) the highly affected zone; 2) the moderately affected zone; and 3) the least affected zone, with special purposes in each zone. It is strongly recommended that future disaster settlement and infrastructure reconstruction policies be based on this zone to reduce disaster risk. Doi: 10.28991/CEJ-2023-09-04-011 Full Text: PD
Evaluating Surface Water Quality Using Indexes of Water Quality and Plankton Diversity
No full textThe study aimed to assess the relationship between surface water quality and the diversity of planktonic communities in An Giang province, Vietnam. The national technical regulations on surface water quality, the water quality index (WQI), and the Shannon-Wiener diversity index (H') were applied to evaluate water quality. The considerable influence of water quality parameters on the dominant plankton was determined by canonical correspondence analysis (CCA) and similarity percentage analysis (SIMPER). The results showed that water quality was contaminated by organic matter, total suspended solids (TSS), and microorganisms. WQI values classified water quality as ranging from bad to good. The species composition of phytoplankton was dominated by two phyla, Chlorophyta and Bacillariophyta, and that of zooplankton was the Rotifera group. SIMPER analysis identified phytoplankton species with dominant density, including Melosira granulata, Pediastrum duplex, Anabaena sp., and Lyngbya circumcreta. Microcyclops varicans, Filinia longiseta, Trichocerca pusilla, Copepoda nauplius, Brachionus caudatus, and Polyarthra vulgarisdominated the density of zooplankton. Temperature, pH, TSS, ammonium, orthophosphate, and coliform considerably influence the dominant species composition of plankton. However, the indicators of diversity and composition of plankton were unable to completely reflect water quality. These findings could contribute to the indicator selection in developing the monitoring water quality programs. Doi: 10.28991/CEJ-2023-09-05-011 Full Text: PD
Shear Performance of GFRP Reinforced Concrete Beams with Seawater and Chopped Fiber
No full textThis paper reports an experimental study on the behavior and shear strength of concrete beams reinforced with longitudinal GFRP bars mixed with sea water. In order to evaluate how much concrete contributes to shear resistance, seven beams were tested in bending. Similar in size and concrete strength, the beams were longitudinally reinforced with glass fiber-reinforced polymer bars; however, they did not even have shear reinforcement. The beams, which measured 3,100 mm in length, 400 mm in depth, and 200 mm in width, were conducted and tested up to failure. The test variables were longitudinal reinforcement ratios (1.0, 1.4, and 2.0%), chopped fiber content (0, 0.5, 2, and 3 kg/m3), and mixing water type (freshwater and seawater). The test findings showed that increasing the reinforcement ratio increased the neutral-axis depth and allowed the formation of more closely spaced fractures while decreasing the loss of flexural stiffness after cracking. By increasing the area of concrete in compression, this in turn enhances the contribution of aggregate interlock as well as the contribution of uncracked concrete. Furthermore, increasing the reinforcement ratio improves the dowel action, which reduces the tensile stresses that are created in the concrete around it. Doi: 10.28991/CEJ-2023-09-04-05 Full Text: PD
Experimental Study on Ultimate Strength of Steel Tube Column Filled with Reactive Powder Concrete
No full textComposite concrete Filled Tubular Steel (CFT) members, which have excellent deformability due to the well-known confined and constrained interaction between steel tube and concrete, have largely been utilized as bridge piers or columns in high-rise buildings, resulting in increased strength and decreased column size. This study examined the experimental performance of steel tube columns filled with reactive powder concrete (RPC) under axial compression. Three sets of columns were used in the experiment, each with variations in shape (square, rectangular, and circular), length-to-diameter ratio, and compressive strength of the RPC. The first set consisted of five columns, while the second and third sets each had seven columns with three different lengths (750 mm, 600 mm, and 450 mm) and two different compressive strengths (54 and 92 MPa). A new numerical model was developed to calculate the ultimate failure load of the columns by considering factors such as the yield strength of steel, the compressive strength of concrete, the column shape, and the ratio of concrete to steel. This model was validated by comparing the results obtained from the experiments to those predicted by the model, as well as by designing equations from various codes. The results showed that the proposed numerical model accurately predicted the ultimate failure load for columns filled with different types of concrete, especially for RPC, while maintaining conservatism compared to the ACI, AISC, and EN codes equations. Doi: 10.28991/CEJ-2023-09-06-04 Full Text: PD
The Behavior of Dredged Soil-Shredded Rubber Embankment Stabilized with Natural Minerals as a Road Foundation Layer
No full textRecently, geotechnical studies have been conducted more progressively to utilize dredged soil. The inclusion of shredded rubber (SR) and natural minerals (NM) to stabilize dredged soil (DS) has become an exciting issue in the geotechnical field. This technique can be a promising environmental innovation for the future. This study aimed to investigate the unconfined compressive strength (UCS), California bearing ratio (CBR), and embankment performance under the strip footing test. The UCS sample was prepared using shredded rubber with a proportion of 2% and 3% and natural minerals with a proportion of 3%, 6%, 9%, and 12% from the dry weight of the soil. Whereas for the CBR samples (both in un-soaked and soaked conditions) were also prepared with a proportion of 2% and 3% shredded rubber and 6% and 9% natural minerals from the dry weight of the soil as well. The strip footing test was conducted in small-scale laboratory tests to evaluate the performance of stabilized dredged soil embankments. The applied load test was gradually increased until the embankment collapsed. The results showed that adding shredded rubber and natural minerals could increase the UCS value by 3–4 times and the CBR value by 2–3 times. Furthermore, 84% and 116% efficient results were obtained in the strip footing test for the 7 and 14 days of curing, respectively. Therefore, the utilization of dredged soil stabilized with SR and NM can be considered for use as a road foundation layer. Doi: 10.28991/CEJ-2023-09-05-016 Full Text: PD
Impact Stiffness of Linear Viscoelastic Model for Seismic Pounding Simulation: An Experimental Evaluation
No full textPounding between adjacent structures occurs when the separating distance within the two buildings is inadequate to contain the movement between them during an earthquake event. Seismic pounding can lead to significant harm or even the destruction of neighbouring structures. In creating a model for structural response, impact stiffness is considered as a critical factor in calculating the impact force throughout the collision within adjacent structures. It is important to derive realistic stiffness values when performing a numerical simulation of pounding forces within abutting structures to attain valid results. The objective of this study is to ascertain the impact stiffness within the linear viscoelastic contact model, using data obtained from shaking table experiments of pounding between neighboring five-storey and 15-storey single-bay model of steel-frame. The steel models were subjected to scaled ground acceleration records, two far-field and two near-field. The study's findings indicate that there is a significant discrepancy between the theoretical impact parameters and the measured experimental value because the assumptions made to derive the theoretical formulas do not align with the actual impact conditions. The accuracy and precision of the experimental formula adopted in this study have been validated in comparison with the numerical results. Doi: 10.28991/CEJ-2023-09-06-01 Full Text: PD