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Performance of Technical Supervision and Its Evaluation on Transport Constructions
No full textThe aim and purpose of the research are to analyze the performance of the technical supervision of the investor within the Czech construction industry during the construction, particularly focused on transport line structures. It is about clarifying the meaning and role of technical supervision in the public sector in transportation structures. In the first phase, a literature search is carried out on the current state of performance of the technical survey, and its work content is determined, including the method of its evaluation within the framework of a public contract. On the basis of these conclusions, a questionnaire is designed, which determines the real time-consuming activities during the performance of supervision and, at the same time, examines the tools used in its performance. Conclusions from the questionnaire research are examined, and steps for possible streamlining are proposed. As part of the examination of the proper evaluation of performance, a more suitable model of evaluation of these services is sought based on the previous analysis of the time-consuming nature of the technical supervision activity and according to the existing evaluation methods. Doi: 10.28991/CEJ-2023-09-03-013 Full Text: PD
The Development of Motorcycle Accident Models Based on Riders' Characters
No full textHuman errors have commonly been perceived as the dominant cause of accidents. Different individuals may behave differently towards certain situations, leading to accidents. This study aims to model the relationship between the riders' personalities, riding performance, and the probability of being involved in an accident. Adding mindfulness as a mediating variable and demographic factors as moderating variables are also essential points to developing the model. The Big Five Inventory (BFI) and Mindful Attention Awareness Scale (MAAS) were used to measure the respondents' traits, while the Honda Riding Trainer (HRT) was used as a simulation tool. The Structural Equation Modelling (SEM) analysis shows that only the neuroticism variable significantly predicts mindfulness and riding performance. The openness and conscientiousness variables only significantly predicted mindfulness, while agreeableness is the only Big Five personality that significantly predicted riding performance. The results also show that although the mindfulness (M) variable in this study has not been able to become a mediating variable, it is strong enough as an exogenous variable for riding performance. The logistic regression analysis found that the worse the rider's performance, the greater the chance of an accident. Female riders are more than twice as likely to have an accident as male riders. These results indicate the need to research road safety that is differentiated by sex and its characteristics based on it. Doi: 10.28991/CEJ-SP2023-09-018 Full Text: PD
Modelling Flood Wave Propagation as a Result of Dam Piping Failure Using 2D-HEC-RAS
No full textIn recent years, there has been a serious request for innovative, accurate approaches to be determined and controlled for dam failures. The present study aims to explore and evaluate the flood wave parameters that result from a dam break due to piping failure occurring in the body of the dam and routing the flood waves. Mosul Dam, which lies in the north of Iraq, and a reach of the Tigris River downstream the dam to Samarra Barrage at about 470 km are selected as a case study. A two-dimensional Hydrologic Engineering Center River Analysis System (2D HEC-RAS) and the Geographic Information System (GIS) have been supposed to be suitable for development calculations of the flood wave parameters based on the Digital Elevation Model (DEM) and land cover satellite images that enhance the calculations. The reservoir and two-dimensional flow area are delineated and incorporated with DEM. Manning`s coefficient for the whole area has been extracted according to the Land Cover satellite image, which showed that its value ranges between 0.025 to 0.037 with a correlation coefficient R2equal to 0.845 and 0.801 for the calibration and validation processes, respectively. The results of the scenario display a substantial performance of the maps produced from the model that represented the depth, velocity, and water surface elevation. All the maximum values of dam break parameters lie near the dam body and slightly decrease downstream. It is pre-eminent that the 2D HEC-RAS model is appropriate for analyzing and simulating the occurrence of dam breaches by visualizing the distribution of flood wave depth and velocities in two dimensions. Hence, the clear improvement in producing maps, which monitor the spread of hydrodynamic waves, gives an indication of risk areas that are threatened by inundation and aids in the formulation of emergency plans. Doi: 10.28991/CEJ-2023-09-10-010 Full Text: PD
Potential Erosion in Mining, Oil Palm Plantations, and Watersheds Reforestation Areas
No full textErosion forecasting is a complex issue generated by numerous causes, the extent of which varies based on the unique area and conditions. Changes in rainfall, land cover, and watershed function are the primary causes of increased erosion. This study aims to scrutinize the actual and potential erosion in the mining area (MA), oil palm plantations (OPP), and watersheds reforestation (WR) in Asoloe, South Konawe, Indonesia. We utilized qualitative research methods and surveys with the USLE model. MA shares the highest actual erosion with 332.30 tons/ha/year, with an average erosion of 27.69 tons/ha/year from 2011 to 2022. Meanwhile, the potential erosion is 4747.19 tons/ha/year, with an average of 395.60 tons/ha/year. In terms of current conditions, 44.6% of rainfall engenders erosion with more than 0.5 t/ha and 33.9% with more than 1 t/ha. This study successfully demonstrates that for given location and area characteristics, high amounts of rainfall and changes in land function eminently affect soil erosion and that the potential erosion changes that occur in the Asoloe watershed every year are exceptionally influenced by changes in land use and land function. Therefore, some mitigation strategies and policies must be taken to reduce the risk of future erosion. Doi: 10.28991/CEJ-2023-09-09-07 Full Text: PD
Shear Performance of Reinforced Concrete T Beams Strengthened by Carbon Fiber-Reinforced Polymer Bars
No full textThe primary purpose of this work is to investigate the shear response of T-reinforced concrete beams strengthened for shear using the embedded through section (ETS) technique when subjected to a monotonic one-point load till failure. The experimental approach included an examination of the twelve reinforced concrete T-beams, including two reference beams without any strengthening and ten strengthened beams. The twelve beams were divided into two main groups, with and without stirrups. The main variables in every group were the spacing and angle of inclination of the carbon fibre-reinforced polymer (CFRP) bars. The beams were strengthened in shear with CFRP bars inserted in the centre line of the section with different spacings and angles of inclination. The experimental analysis was performed to study the effect of spacing and angle of inclination of the CFRP bars on the ultimate load capacity, load-strain relationships, and load-deflection relationships. Results showed that the ultimate load of the beams in group one with inclined CFRP bars (45°) increased by 29.7, 22.4, and 15.5% for beams with CFRP bar spacings of 10, 15, and 20 cm, respectively, compared with the reference beam. In group one (with stirrups), the beam with inclined CFRP bars (45°) and a spacing of 10 cm has an ultimate load higher than that with vertical CFRP bars (90°) with a similar spacing by 2.6%. By contrast, the beam with inclined CFRP bars (45°) and a spacing of 10 cm in group two (without stirrups) has an ultimate load higher than that with vertical CFRP bars (90°) with a similar spacing by 2.5%. Doi: 10.28991/CEJ-2023-09-10-04 Full Text: PD
Watershed Delineation from DEM by Model Builder in ArcGIS
No full textThe water level fluctuates continuously at local, continental, and global levels. Consequently, remote sensing offers extensive data for assessing the location, extent, and variability of change, including the causes and changes that occur and the reactions and repercussions of change. Considering the significance of the water level, this research focuses on describing the methodology and process to determine the water level in the Al-Zab River. This study offers a straightforward and cost-effective approach and procedure for precisely delineating flood danger regions in the Al-Zab River basin utilizing a geographic information system and the existing database. The proposed strategy for regionally dispersing flood risks combines the size of prior flood events and the geographical distribution of their causes. This approach allows for the calculation of a weighted score for each participant's causative component. The regional distribution of the flood hazard intensity level is obtained by categorizing the spatial patterns of the flood hazard index. The 30-m digital elevation model with a high resolution was utilized to evaluate the water level in this river. Furthermore, this work is considered the first step towards enhancing information management in the studied area. This study mainly aims to explain how to outline and define watersheds using ArcGIS for flood mapping. Doi: 10.28991/CEJ-2023-09-11-011 Full Text: PD
Technical Audit and Unethical Practices in the Construction Industry
No full textThis study presents the dark side of "unethical practices" in construction projects in Egypt, which impact the construction industry's development. It also identifies the project parties' unethical practices in funded projects and the Technical Audit's role in fighting them. A mixed methodology was used for collecting and analyzing quantitative and qualitative data. The study results indicated the owner's and bidder's unethical practices were Disclaim liability for nominated subcontractor mistakes and submitting an unbalanced bid, respectively. Also, the procedure militating against the practices was adopting and applying the technical audit concept to governmental projects. Separate analyses revealed differing viewpoints among consultants, owners, and contractors. The study contributes to the creation of honest competition to develop the construction industry, reducing public money losses, and evaluating competitors on a stable and sound basis. Also, building awareness and sensitizing our community to the construction project's dark side is necessary for getting a legally sustainable solution in future tender law formulation. Doi: 10.28991/CEJ-SP2023-09-014 Full Text: PD
Efficient Multi-Composite Cement Made of Granulated Blast Furnace Slag (GBFS) and Flash-calcined Sediment
No full textThe objectives of this study were to find out in detail how well granulated blast furnace slag (GBFS) could be replaced by flash-calcined sediment (SF sediment) in terms of hydration kinetics and mechanical-microstructural properties when developing an eco-friendly cement binder. The results indicated that the SF sediment substitution with a rate of 25% wt significantly improved the hydration kinetics of cement compared to the reference. This contributed to a considerable enhancement of the mechanical-microstructural properties of the mortar containing the SF sediment. By comparison with the reference, the strength of multi-composite cement-based mortar increased by 33% at 2 days and by 4.5% at 28 days, whereas its porosity decreased by 16.32% and by 12.44% for the same period. The SEM-EDS result showed that the SF sediment substitution did not significantly modify the chemical composition of the C-S-H phase, with a Ca/Si ratio range of 1.82 to 2.84 for both cement pastes. Moreover, Mg2+ and Al3+ions were two principal elements incorporated in C-S-H gels, with different ratios depending on the Ca/Si ratio of C-S-H gels. A novel model established from a combination of the curve fitting method and Power's approach allowed for accurate prediction of the strength development of multi-composite cement-based mortars. Overall, the SF sediment substitution could be considered a promising option to develop a more eco-friendly cement binder, while the novel approach could be used as a reliable model for the strength prediction of blended cement. Doi: 10.28991/CEJ-2023-09-11-02 Full Text: PD
Strength and Chemical Characterization of Ultra High-Performance Geopolymer Concrete: A Coherent Evaluation
No full textThe objective of this review article is to analyze published data encompassing compressive strength, tensile strength, elastic modulus, and flexural strength, as well as the utilization of scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD) for Ultra High-Performance Geopolymer Concrete (UHP-GC), with the focus of establishing the current research trends regarding its mechanical, microstructural, and chemical characteristics. After a critical evaluation of the published data from the literature findings, it became evident that UHP-GC can attain a remarkably high level of engineering performance. In UHP-GC, the optimum percentage of silica fume as a slag partial replacement to achieve high compression, tensile, and elastic modulus were traced to be 25, 30, and 35%, respectively. The optimum ratio of sodium silicate to sodium hydroxide and sodium hydroxide molarity for UHP-GC were identified to be 3.5 and 16, respectively. All in all, the review provides a thorough understanding of the review gap and distinct functions of different raw materials in decreasing porosity and enhancing the formation of geopolymeric gels that not only bond but also strengthen UHP-GC. UHP-GC stands as an energy-saving material in concrete technology, poised to forge a path towards a sustainable future for the building sector. Doi: 10.28991/CEJ-2023-09-12-020 Full Text: PD
Finite Element Analysis of Two Nearby Interfering Strip Footings Embedded in Saturated Cohesive Soils
No full textThe issue of interaction between nearby footings is of paramount practical significance. The interference effect should be taken into account since the footing may really be separated from or bounded by other footings on one or both sides. In this regard, this paper studies the effect of two nearby interfering strip footings embedded in saturated cohesive soils, which will help to provide a better understanding of the impact of footing depth on the interference effect. A numerical study is carried out using the finite element program (Midas GTS-NX), and the behavior of closely placed strip footings embedded in the saturated cohesive soils is investigated under the influence of different factors such as the spacing between footings, the depth of footings, soil undrained shear strength, and the groundwater table. It was concluded that the soil cohesion and the footing depth ratio have a notable influence on the interference of closely spaced footings. For all cohesion values, it has been observed that the spacing needed for interference to vanish decreases with an increase in the depth of the footing and water table. In addition, as the S/B ratio increases, the ultimate bearing capacity (UBC) of interfering footings decreases until it reaches the same value as an isolated footing at greater spacing. The UBC is approximately 10% higher at S/B = 1 compared to the isolated footing. However, at S/B = 1, the UBC of two footings achieves a value equal to that of an isolated footing and does not change when the S/B ratio increases. With increasing footing depth, there is an increase in UBC. Finally, the highest values of x were obtained in all cases when Cu = 40 kPa. This indicates that the interaction between footings is greater when the soil is softer. Doi: 10.28991/CEJ-2023-09-03-017 Full Text: PD