2031 research outputs found
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Evolution and Implications of Changes in Seismic Load Codes for Earthquake Resistant Structures Design
Get PDFSeismic load is a critical load that can trigger damage or collapse of structures, especially in earthquake-prone areas. The susceptibility of structures to seismic loads is influenced by factors related to soil characteristics and structural behavior. This paper comprehensively examines the development of Indonesian seismic code design parameters and their comparison with the current seismic code. The results of the analysis showed that the design spectral acceleration of short-period AD and long-period A1 SKBI 1987 and SNI 2002 increased with increasing PGA values, with a consistent pattern of SC < SD < SE. Unlike the previous two codes, design spectral acceleration AD and A1 SNI 2012 and SNI 2019 experience fluctuations in all types of soil. The ratio design spectral acceleration of AD and A1 SNI 2019 to KBI 1987 and SNI 2002 varies; there are up, fixed, and down for SC, SD, and SE soil conditions. The ratio of design spectral acceleration AD and A1 SNI 2019 to SNI 2012 designs also varies; this condition is due to changes in site coefficients. There were significant changes to the SKBI 1987 and SNI 2002 structural systems, especially the low and medium seismic levels. The increase in the seismic influence coefficient ratio of some cities varies for each type of soil and code. The increase in the 1970 PMI seismic coefficient was < 30% for all soil types, and the highest percentage increase occurred in SC soil types. The increase in seismic coefficient in SKBI 1987, SNI 2002, and SNI 2012 is more dominant in SE soil types. Doi: 10.28991/CEJ-2024-010-01-04 Full Text: PD
Analysis and Prediction of Tidal Measurement Data from Temporary Stations using the Least Squares Method
Get PDFThis research was conducted by equipping three temporary tidal stations located in three places inside Palu Bay with pressure-type tidal gauges. The stations recorded tidal series fluctuations for 4 months with a 5-minute sampling interval (Dt). Moreover, the simple and widely used least squares method (LSM) was applied to separate the harmonic constants of constituents, including amplitudes (Hi) and phases (gi), from the observed tidal series. A total of 11 dominant constituents were selected based on the largest magnitudes of tidal generating potential (CE), and these include M2, K1, S2, O1, P1, N2, Mf, K2, Mm, Q1, and Msf, which were diurnal, semidiurnal, and long-period constituents. The results showed that the semidiurnal constituents generated higher amplitudes than the diurnal constituents, while the long-period constituents produced quite small amplitudes. Furthermore, the ratios of amplitudes recorded showed that tidal in Palu Bay was mainly mixed with semidiurnal constituents. The difference between the observed and predicted values was quite small, and this showed the validity of the measurement conducted at the temporary tidal stations. The performance indicators applied also showed that LSM had acceptable accuracy compared to other methods. Moreover, tidal datums were calculated using the peak approach, and the average tidal range (RA) of Palu Bay was found to be 2.39 m. Doi: 10.28991/CEJ-2024-010-02-03 Full Text: PD
Experimental and Numerical Simulation of Effects of High Temperature on RC Frame Infilled with Sandwich Panel
Get PDFThis study investigated the structural behavior of reinforced concrete (RC) frames infilled with masonry walls and polyurethane (PU) sandwich wall panels at elevated temperatures. This study aims to assess the influence of temperature on the stiffness and load-carrying capacity of infilled frames, optimize the thickness of the sandwich wall panel, and compare the performance of masonry and sandwich infill systems. Analytical investigations were conducted using finite element analysis software (ABAQUS) to simulate the behavior of the frames at elevated temperatures and consider various configurations of skin thickness for PU sandwich panels. Experimental tests were performed to validate the analytical results. The frames were subjected to transient temperature conditions and uniform unit loads to evaluate their response. Experimental tests were conducted on RC frames infilled with masonry and sandwich-wall panels at elevated temperatures. The frames were subjected to static loading, and their deformations and failure modes were observed. The analytical study revealed that an increase in the skin thickness of the sandwich panel improved its temperature resistance, stress-withstanding ability, and displacement. A skin thickness of 0.45 mm was determined to be the optimal choice considering stress levels and economic factors. The infilled frame with the sandwich wall panel exhibited a 19.22% higher initial stiffness than the masonry wall panel in the experimental tests. The ultimate load-carrying capacity decreased by 17.86% in the infilled sandwich wall panel frame compared to the masonry infill system. The study provides valuable insights into the behavior of RC frames infilled with masonry walls and sandwich wall panels under elevated temperatures. The optimized thickness of the PU sandwich panel was determined by balancing the thermal resistance and the structural performance. The infilled frames with sandwich wall panels exhibited enhanced stiffness but slightly reduced ultimate load-carrying capacity compared with the masonry infill. These findings contribute to the understanding of thermal effects on building structures and can aid in the design and construction of more resilient and efficient buildings in the future. Doi: 10.28991/CEJ-2024-010-01-018 Full Text: PD
Experimental investigations: Reinforced Concrete Beams Bending Strength with Brine Wastewater in Short Age
Get PDFThe scarcity of waste in some regions has led to the contemplation of other approaches to providing potable water for human use. In the present research, it is proposed that a portion of the brine wastewater be recycled for potable water purposes through its incorporation into concrete and reinforced concrete compositions. The researchers performed an extensive empirical investigation to examine the impact of incorporating brine wastewater into the concrete mixture on the shear strength, bending stress, and compressive strength of the material. A total of seventy-two beams, each measuring 500 mm in length, 100 mm in width, and 100 mm in depth, were observed. A total of twelve beams were designated as control specimens, while an additional sixty beams were subjected to immersion in brine wastewater at varying concentrations of 2.5, 5, 7.5, 10, and 15%. The beams were reinforced using two longitudinal steel bars with a diameter of 8 millimeters in the tension zone and 6 millimeters in the compression zone. The stirrups included in the study were also measured to have a diameter of 4 mm. The samples were examined at intervals of seven, fourteen, twenty-one, and twenty-eight days. Based on the findings of this study and other relevant studies, it was determined that the use of 10% fresh water as a substitute for brine wastewater yielded the most optimal outcomes. The results obtained after a duration of 28 days indicate a notable increase in both the compressive and bending strengths of the concrete samples, with improvements of around 22% and 2.6% seen in comparison to the reference specimens. The impact of brine wastewater on the corrosion of reinforcing steel in reinforced concrete was investigated. The empirical findings indicated that the introduction of brine wastewater at a concentration of 10% to the concrete constituents did not provide any discernible repercussions over a period of 65 days. Doi: 10.28991/CEJ-2024-010-01-010 Full Text: PD
Estimation of the Physical Progress of Work Using UAV and BIM in Construction Projects
Get PDFThe delay in the physical progress of construction creates additional costs, missed deadlines, and quality issues. The research aimed to estimate the physical progress of the project by using unmanned aerial vehicles (UAVs) and building information modeling (BIM). The methodology comprised capturing 848 high-resolution images of the Civil Engineering Laboratory construction site at the National University of Jaen, Cajamarca, Peru, using the Phantom 4 RTK drone. The photographs were processed using Agisoft 2.0.1 software, resulting in a point cloud. This was then imported into ReCap Pro 2023 software, which was used to assess the quality of the points. The Revit 2023 software was subsequently utilized to establish the phase parameters, linking the BIM model with the point cloud, filtering the model, and eventually exporting it to the Power BI 2023 software. The work's estimated progress utilizing the proposed methodology was 42.82%, which was not statistically significant compared to the Public Works Information System (INFOBRAS) of 43.14%. This allows for the automation of customary processes, the identification of crucial issues, and prompt decision-making. The study's originality lies in the suggestion of integrating aerial imagery with drones and BIM modeling for the real-time and precise estimation of work progression. This method provides a precise and effective substitute for traditional techniques for gauging the tangible advancement of projects. Doi: 10.28991/CEJ-2024-010-02-02 Full Text: PD
The behavior of Shear Connectors in Steel-Normal Concrete Composite Structure under Repeated Loads
Get PDFIn today's construction industry, the use of composite beams is becoming more and more important, particularly for long-span bridges that must withstand repeated loads from moving automobiles. This work investigates the behavior of composite beams through experimentation. Six push-out steel-concrete specimens are made and tested with various levels of static and repetitive loading applied. The specimens are made of rolled steel sections that are joined to concrete decks on both sides by stud shear connectors. Two approaches”one static and the other repeating”applied a push-out load to two sets of samples. One has a stud shear connector measuring 16 mm, and the other measures 25 mm. Three specimens were made for each group. To determine the final load, one specimen from each group underwent a static push-out test in the first stage. In the subsequent phase, repeated loads of 0-80% and 25-80% of the maximum static load were applied to the remaining ones. The analysis process measured the variation in slip between the concrete decks and the steel section over several load cycles. It was found that the recorded slip values at the ultimate load increased about four times just before the failure. The recorded values of the residual slip at the end of each load cycle decreased with the increase in load cycle numbers. Also, it was found that the values of the residual slip depend on the values of the lower and upper limits of the load level. Doi: 10.28991/CEJ-2024-010-01-013 Full Text: PD
Construction Project Delay Risk Assessment Based on 4M1E Framework and Afghanistan Situation
Get PDFIn the realm of construction project management, delays present a significant impediment, particularly within complex socio-political contexts such as Afghanistan. This study endeavors to elucidate the multifaceted nature of construction project delays in Afghanistan, employing the 4M1E (Man, Machine, Material, Method, and Environment) framework to conduct a comprehensive risk assessment. The research methodology entailed the development of a structured questionnaire grounded in an extensive review of pertinent literature, targeting 30 recognized causes of project delays. This instrument was administered to a representative sample of 144 professionals across the Afghan construction industry spectrum, including clients, consultants, and contractors. Analytical rigor was applied through the deployment of frequency, severity, and importance indices to evaluate the collected data. This analysis culminated in the distillation of ten paramount delay risk factors, encapsulating elements such as governmental policy stability modifications in project scope and design alongside delays in material testing and approval processes. A comparative dimension was incorporated to benchmark these findings against global standards, thereby enhancing the robustness of the study's conclusions. Moreover, the research delineates the congruence and discordance among different respondent cohorts, bolstering the integrity of the identified delay factors through a validation of internal consistency and reliability. The strategic application of the 4M1E framework, contextualized within the Afghan construction landscape, furnishes pivotal insights for stakeholders, equipping them with a nuanced understanding necessary for the proactive mitigation of delay risks. The implications of this study are far-reaching, promising to augment project completion efficiency, budget adherence, and overall project success, with particular resonance for environments paralleling the intricacies of Afghanistan. Doi: 10.28991/CEJ-2024-010-01-06 Full Text: PD
Integration of Artificial Intelligence Applications and Knowledge Management Processes for Construction Projects Management
Get PDFArtificial intelligence systems have gained access to various scientific and research fields, especially in the construction industry. The study seeks to confirm the vital role of introducing Knowledge Management (KM) integrated with Artificial intelligence (AI) applications in the projects. It requires qualifying engineers and imposing their current qualifications to achieve the benefits of Integration of AI Applications based on KM processes to perform their professional roles and recognize the need to develop their capabilities through training and development. The field survey was intended only for 85 engineers working on construction projects (public and private sectors). Three axes were clarified to allocate the extent of the sample response and determine the benefits of using the KM process and AI applications for the success of construction projects. The results showed a positive relationship between the demographic variables of the response and the benefit of using the KM process and AI applications and explaining the variance in the regression relationships. Therefore, the study suggests integrating AI applications based on the KM process to achieve business goals and effectively benefit and exchange management, as its use leads to faster and more effective decision-making, especially if the project strategy approves it. Doi: 10.28991/CEJ-2024-010-03-06 Full Text: PD
Modelling of Flood Hazard Early Warning Group Decision Support System
Get PDFEarly warning of flood hazards needs to be carried out comprehensively to avoid a higher risk of disaster. Every decision on early warning of a flood hazard is carried out in part by one party, namely the government or water resource managers. This research aims to provide a collaborative decision-making model for early warning of flood hazards through a Group Decision Support System Model (GDSS), especially in Indonesia. The novelty of this research is that the GDSS model involves more than one decision-maker and multi-criteria decision-making for early warning of flood hazards in the downstream Kali Sadar River, Mojokerto Regency, East Java Province, Indonesia. The GDSS model was developed using a hybrid method, namely the Analytical Network Process (ANP) and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR). There was more than one decision result; voting was carried out using the BORDA method to produce the decision. The test results of GDSS were obtained using a Spearman rank correlation coefficient of 0.8425 and matrix confusion, an accuracy value of 86.7%, a precision value of 86.7%, a recall value of 86.7%, and an f-measure of 86.7%. Based on the test results, good results were obtained from the GDSS model. Doi: 10.28991/CEJ-2024-010-02-018 Full Text: PD
Experimental and Numerical Analysis of Concrete Columns under Axial Load Based on European Design Norms
Get PDFThis study presents a comparison between numerical and experimental results for reinforced concrete columns subjected to axial compression. Depending on the columns support and their organization within the structure, columns primarily work under either concentric or eccentric compression, respectively, bending in situations where horizontal actions such as wind or/and earthquakes are present in the structure. Different countries have specific design codes, and in this study, the calculation of columns is based on the European design codes, specifically EN 1992-1-1. As a common practice in most cases during research, tests are conducted using computational models, and based on the obtained results through the application of similarity theory, an attempt is made to transition to the actual behavior of structural elements. Therefore, this paper applies a logic of "almost real" testing, where two columns with square cross-sections were produced and tested. The columns had a rectangular base with cross-section dimensions of 20/20 cm and a height (L) of 300 cm, with a concrete strength of fcm,cube=61.80 MPa. They were reinforced with longitudinal reinforcement (4í˜12 mm) and had a tensile strength of ftm=588.10 MPa. Additionally, stirrups of í˜8 mm were placed at every sw=25 cm. Experimental results show a closer alignment with software calculations using SEISMOSOFT with an accuracy of 96%, while results according to EN 1992-1-1, based on simplified methods, show 64% for the Nominal Stiffness Method and 59% for the Curvature Method. Doi: 10.28991/CEJ-2024-010-02-05 Full Text: PD