Journal of the Civil Engineering Forum
Not a member yet
225 research outputs found
Sort by
Numerical Modelling Based on Digital Elevation Model (DEM) Analysis of Debris Flow at Rinjani Volcano, West Nusa Tenggara, Indonesia
Full text linkDebris flow is a disaster occurring in cases where a sediment particle flows at high speed, down to the slope, and usually with high viscosity and speed. This disaster is very destructive and human life-threatening, especially in mountainous areas. As one of the world’s active volcanoes in the world, Rinjani had the capacity to produce over 3 million m3 volume material in the 2015 eruption alone. Therefore, this study proposes a numerical model analysis to predict the debris flow release area (erosion) and deposition, as well as the discharge, flow height, and velocity. The Digital Elevation Model (DEM) was analyzed in ArcGIS, to acquire the Cartesian coordinates and “hillshade” form. This was also used as a method to produce vulnerable areas in the Jangkok watershed. Meanwhile, the Rapid Mass Movement Simulation (RAMSS) numerical modeling was simulated using certain parameters including volume, friction, and density, derived from the DEM analysis results and assumptions from similar historical events considered as the best-fit rheology. In this study, the release volume was varied at 1,000,000 m3, 2,000,000 m3, and 3,000,000 m3, while the simulation results show movement, erosion, and debris flow deposition in Jangkok watershed. This study is bound to be very useful in mitigating debris flow as disaster anticipation and is also expected to increase community awareness, as well as provide a reference for structural requirements, as a debris flow prevention
Feasibility Evaluation of Wastewater Treatment Plant System: A Case Study of Domestic Wastewater System in Sleman Regency, Yogyakarta, Indonesia
Full text linkDomestic Wastewater Treatment Plant (DWWTP) type 1 and DWWTP type 2 were being evaluated. DWWTP type 1 is located in Sembir area while DWWTP type 2 is located in Tambakrejo area which are both in Sleman Regency, Special Region of Yogyakarta (Daerah Istimewa Yogyakarta or DIY), Indonesia. The emphasis of this research is to choose the manhole material which has the least leakage to the soil, influent discharge performance and wastewater treatment quality effluent. The method used to measure the discharge was by averaging daily discharge for twelve hours, while the E. Coli bacteria under the manhole was also being analyzed. Pollution Index method was also used to evaluate the pollution levels of the wastewater treatment effluent. Results of the study indicated that DWWTP type 1 performance was not optimal because the number of users was greater than that of the design. The impacts were excessive capacity, improper detention time and several parameters of the effluent did not meet the Indonesian legal regulation, including Chemical Oxygen Demand (COD), with efficiency of 34.43%. Wastewater treatment quality effluent parameters which met the Indonesian legal regulation were pH, TSS, TDS, Oil and Grease and Chlorine for DWWTP type 1. Pollution Index (PI) of DWWTP type 1 was 7.02 and PI of DWWTP type 2 was 6.96 which were relatively categorized as moderately polluted. DWWTP type 2 performance was optimal with mean discharge lower than the design discharge. Parameters of the effluent which met the Indonesian legal regulation were pH, TSS, TDS, Oil and Grease, Detergent and COD for DWWTP type 2. The COD of DWWTP type 2 met the Indonesian legal regulation with high efficiency of 73.24%. The E. Coli bacteria was not found in soils under the ring type precast concrete manholes. Hence ring type precast concrete base manhole is recommended
The Effect of Bridge Piers on Local Scouring at Alue Buloh Bridge Nagan Raya Regency
Full text linkScouring that occurs in cross-section a river can be caused by morphological conditions of the river and the effect of bridge piers that obstruct the flow. Availability of piers and abutments can cause the stability of soil base granules to be disrupted, downflow, and horseshoe vortex that causes soil base granules around the bridge pier to be transported the flow that causes occurrence in local scouring. The problems of local scours also occurred in Krueng Ineng river, Alue Buloh Village, Nagan Raya Regency. The problem that is often encountered due to bridges being built across rivers is the lack of functioning of the under-bridge structures. Local scours on the bridge piers will cause a structural collapse which has the impact of decreasing the stability of the bridge structure currently. In this study, local scour analysis are using empirical equations with the Froehlich, Lacey and Colorado State University Method. The Results of the analysis with used the peak discharge (Qp100) that occurs in the Krueng Seunagan watershed is 1513m3/sec. Analysis with a flow depth of 3.06m, Froude number 0.29, pier width with lenticular shaped 4m, and D50, D95 (average grain size analysis ) 0.91mm and 4.35mm, show a maximum scour depth at the field of 1.65m and 1.68m occurs in point (station) 2 and 3 on segment 5. Analysis with the Froehlich, Lacey Method and the CSU Method shows a scour depth is 1.68m, 4,47m (Qp100) and 2.43m. The closest measurement result in the field is the Froehlich Method. With this result, it might be input for local governments to plan appropriate handling for minimizing local scour in this study are
Effect of Well Resistance on Time Factor Ratio Due to PVD Deformation
Full text linkOne of the most common soft soil enhancement techniques used to expedite the consolidation time significantly is Prefabricated Vertical Drains (PVD). This technique needs a sufficient discharge capacity value because it primarily functions as a drainage channel. The deformation of PVD is considered as one of the primary factors which affect discharge capacity. Therefore, this research determined the influence of upper-side deformation on PVD's discharge capacity (qw) using a specific design apparatus known as ASTM D4716, which manages the determination of transmissivity and flow rate at the longitudinal direction of geosynthetics. Furthermore, two PVD samples with dimensions of 3 and 4 mm thickness, 100 mm width, and 1000 mm length were examined under straight and buckled conditions. Stepwise confining pressures from 50 to 200 kPa were subjected to the samples under hydraulic gradients with values of 0.2, 0.5, and 1.0. The results showed that samples with greater thickness had higher discharge capacity, which significantly reduced in the lower hydraulic gradient. The deformation on the upper side of PVD induced a decrease of discharge capacity by approximately 13-16%, which led to a delay in the consolidation time. The discharge capacity values obtained from the experiments were employed as parameters in a time factor ratio of Th,w/Th. The analysis results show that the buckled PVD has a more considerable consolidation time due to the increase in the Th,w/Th ratio, with a discharge capacity value below 10-4 m3/s. It can be concluded that the deformation in the form of buckled conditions on the upper side of PVD had a considerable impact on PVD effectiveness
Crack Detection on Concrete Surfaces Using Deep Encoder-Decoder Convolutional Neural Network: A Comparison Study Between U-Net and DeepLabV3+
Full text linkMaintenance of infrastructures is a crucial activity to ensure safety using crack detection methods on concrete structures. However, most practice of crack detection is carried out manually, which is unsafe, highly subjective, and time-consuming. Therefore, a more accurate and efficient system needs to be implemented using artificial intelligence. Convolutional neural network (CNN), a subset of artificial intelligence, is used to detect cracks on concrete surfaces through semantic image segmentation. The purpose of this research is to compare the effectiveness of cutting-edge encoder-decoder architectures in detecting cracks on concrete surfaces using U-Net and DeepLabV3+ architectures with potential in biomedical, and sparse multiscale image segmentations, respectively. Neural networks were trained using cloud computing with a high-performance Graphics Processing Unit NVIDIA Tesla V100 and 27.4 GB of RAM. This study used internal and external data. Internal data consisted of simple cracks and were used as the training and validation data. Meanwhile, external data consisted of more complex cracks, which were used for further testing. Both architectures were compared based on four evaluation metrics in terms of accuracy, F1, precision, and recall. U-Net achieved segmentation accuracy = 96.57%, F1 = 87.55%, precision = 88.15%, and recall = 88.94%, while DeepLabV3+ achieved segmentation accuracy = 96.47%, F1 = 85.29%, precision = 92.07%, and recall = 81.84%. Experiment results (internal and external data) indicated that both architectures were accurate and effective in segmenting cracks. Additionally, U-Net and DeepLabV3+ exceeded the performance of previously tested architecture, namely FCN
The Application of Combined Phytoremediation Greywater Treatment in A Single House
Full text linkA report showed 22% of households in Indonesia did not have a proper sanitation facility in 2018 and this caused the potential discharge of their wastewater directly to the surface water, thereby, polluting the water and its surrounding environment. The quality of water resources is also declining nationwide due to pollution and this affects the cost of water treatment, therefore, it is necessary to determine the most effective treatment method to reduce this pollution. However, one of the breakthroughs observed to have met the criteria of low cost, simple operation and maintenance, and energy-saving is greywater treatment using plants (phytotechnology) combined with solar ultraviolet (UV) system. This research was, therefore, conducted to evaluate the performance of the coupled greywater treatment and investigate the possibility of its implementation in the actual condition of a selected single house. Moreover, the physical treatment and phytoremediation were combined with solar disinfection treatment, and the units selected include a collection and sedimentation chamber, filter, phytoremediation, and solar disinfection chamber. The flowrate was measured based on the difference in water level over time while the influent and effluent quality was evaluated at the inlet of the sedimentation chamber and outlet of the disinfection chamber. The results showed the organic efficiency removal was up to 92% while the solids content was found to be high at 49% and the system was able to effectively remove the ammonia at 57% and reduce the pathogenic bacteria by 88%. Moreover, the treated water quality known as the effluent met all the requirements of the Provincial Regulation of Central Java No. 5 of 2012 and Class 3 standard (water for cultivation of plants and fisheries) of Indonesian Government Regulation No. 82 of 2001. However, it did not meet the standard for toilet flushing water according to the standard from U.K, U.S.A, and Australia. This means the treatment system was unable to produce an effluent with the ability to replace the water use indoor. Therefore, it is recommended that an advanced treatment system for greywater such as Submerged Membrane Bioreactor be applied to maximize the intake of treated greywater for indoor and outdoor uses
Determination of Optimal Rain Gauge on The Coastal Region Use Coefficient Variation: Case Study in Makassar
Full text linkThe quality of rainfall data is highly significant in disaster analysis, ecology, and water resource management. However, the accuracy and quantity of rain gauges are often inadequate, especially for analyzing extreme events, including the Makassar City flood, in 2019. This inadequacy is due to several reasons, including rain gauges’ inadequacy and insufficient distribution. This study, therefore, aims to analyze the requirements of optimal rain gauges, using coefficients of variation in various error levels, based on the latest rainfall data in several locations within Makassar City. Monthly and yearly rainfall observation data from 2010 to 2019 obtained at 5 locations were used to calculating the optimal rain gauge number. According to the results, the existing station has a 10% and 15% monthly and annual error, respectively. This region has 3 groups causing highly optimal rain gauges, and these are the first group comprising Paotere, Panaikang, as well as Biring Romang, while the second and third groups comprise Sudiang and Barombong. The northwest wind blows towards the coast and crosses these three places in a line, thus, causing rainfall intensity with a slight disparity, between the first group. Furthermore, the combination of these places resulted in low optimal rain gauge. However, the combination of the first group with the second and third lead to an increase in the optimal rain gauge number. The low elevation, proximity, and location of the first group’s three locations in line with the rain-causing wind results in low optimal rain gauge. In the combination of the first, second, and third groups, additional gauges are required to obtain a 5% or 10% error. The rainfall intensity and position greatly influence the rain catchment in Makassar, and consequently, the optimal rain gauge number. In addition, the distance, topographical aspects, and the combined land-sea and monsoonal winds’ factors must also be analyzed, in deploying equipment
The Influence of High Plasticity and Expansive Clay Stabilization with Limestone on Unconfined Compression Strength
Full text linkClay is a cohesive material that becomes very soft when high content of water is added. This condition makes construction activities difficult on this type of soil. There is, therefore, a need for stabilization when dealing with high plasticity clay through several methods such as the application of limestone. However, this method mostly does not meet the standards due to the reaction between limestone and groundwater which normally alters soil properties, thereby, leading to a reduction in stickiness and softness of the soil. Meanwhile, limestone generally has the ability to compact and stabilize the soil due to its fine powder which consists of metals and non-organic mineral compositions. Therefore, this study was conducted to identify the influence of using limestone additives for stabilization at different mixture compositions on clay. The properties of the soil were tested before the Unconfined Compression Strength Test and the results showed limestone was effective in stabilizing high plasticity and expansive clay. This was proven by the 10% increase in the Unconfined Compression with lime content in curing conditions for 28 days as well as the 319% magnitude of the non-soaked, 6% reduction in the liquid limit value, and 46% increment in the plastic limit value
Quantity Surveyors’ Response to the COVID-19 Outbreak: A Mixed Method Approach
Full text linkThe COVID-19 outbreak began at the end of 2019, and has evolved to a pandemic threatening various industries’ sustainability. Decisive actions have been taken to tackle the pandemic’s spread, however, various impacts continue to be felt by many industries, including the construction industry. This paper therefore focuses on the COVID-19 outbreak’s impact on Quantity Surveyors’ (QS) construction projects and activities, as a key profession in the industry. A mixed method approach, questionnaire survey followed by expert interviews, was adopted. Subsequently, 199 valid responses for analysis were obtained from the questionnaire distribution, using descriptive statistics and Significance Index. Furthermore, qualitative data were acquired through semi-structured interviews with five experts, and analyzed using a structured thematic analysis. According to the results, 56.78% of respondents experienced project slowdowns, 13.57% experienced project suspensions or terminations, and 12.56% experienced cost overruns. Most respondents acknowledged the pandemic had present changes to projects (84.92%), in the form of changes in organization structure, work culture, technological application, and project objectives. Meanwhile, the Significance Index has successfully established an 11-factors ranking, regarding the pandemic’s impact on QS activities, with impact on the overall project completion as the most profound impact followed by impacts on project scheduling, supply chain, tendering, cost controlling, and claim management. This study’s qualitative and quantitative findings tend to be in accordance, thus, providing some fundamental insights regarding the COVID-19 outbreak’s impact on the construction industry, including direct impacts on project sustainability, technology adoption, and project resiliency issues. In addition, this study also contributes to scientific knowledge by discussing the issues and trends of work culture changes in QS professional activities
Flood Mapping in the Coastal Region of Bangladesh Using Sentinel-1 SAR Images: A Case Study of Super Cyclone Amphan
Full text linkFloods are triggered by water overflow into drylands from several sources, including rivers, lakes, oceans, or heavy rainfall. Near real-time (NRT) flood mapping plays an important role in taking strategic measures to reduce flood damage after a flood event. There are many satellite imagery based remote sensing techniques that are widely used to generate flood maps. Synthetic aperture radar (SAR) images have proven to be more effective in flood mapping due to its high spatial resolution and cloud penetration capacity. This case study is focused on the super cyclone, commonly known as Amphan, stemming from the west Bengal-Bangladesh coast across the Sundarbans on 20 May 2020, with a wind speed between 155 -165 gusting up to 185 . The flooding extent is determined by analyzing the pre and post-event synthetic aperture radar images, using the change detection and thresholding (CDAT) method. The results showed an inundated landmass of 2146 on 22 May 2020, excluding Sundarban. However, the area became 1425 about a week after the event, precisely on 28 May 2020 . This persistency generated a more severe and intense flood, due to the broken embankments. Furthermore, 13 out of 19 coastal districts were affected by the flooding, while 8 were highly inundated, including Bagerhat, Pirojpur, Satkhira, Khulna, Barisal, Jhalokati, Patuakhali and Barguna. These findings were subsequently compared with an inundation map created with a validation survey immediately after the event and also with the disposed location using a machine learning-based image classification technique. Consequently, the comparison showed a close similarity between the inundation scenario and the flood reports from the secondary sources. This circumstance envisages the significant role of CDAT application in providing relevant information for an effective decision support system