Crack formation and propagation in reinforced concrete members is complex. It involves various mechanisms and parameters related to the interaction between concrete and reinforcement, the geometry of structural members, type of loading, and support conditions. These factors can be controlled and adjusted to some extent only. On the other hand, these deterministic factors are all superimposed by a certain level of randomness owing to the fluctuations of material parameters and the heterogeneous composition of concrete. Nevertheless, the process of cracking and the resulting crack systems have been widely studied during the years, striving to create physically transparent models that could predict the structural behavior with greater accuracy. Considering the importance of flexure and shear failure influences on strength of concrete, percentage of steel and stirrups of RC beam, a finite element (FE) modeling that focuses on crack initiation and pattern is presented in this study. Nonlinear three dimensions finite element analysis (FEA) of RC beam capable of appropriately modeling the concrete stress-strain behavior, tensile cracking, and compressive damage of concrete and indirect modeling of the steel-concrete bond is performed using ABAQUS to investigate the ultimate load, beam displacements, and cracking pattern. The concrete damage plasticity is applied to the numerical model as a distributed plasticity over the whole geometry. The objective of this study is to predict failure and crack development in the concrete model using ABAQUS for static load in M30 grade beam with different reinforcement configurations and results have been compared with the experimented sample.
Original Research Article
June 22, 2021
A Study on the Service Quality of Launch Terminal Based on Passengers’ Satisfaction at Sadarghat Dhaka
Purpose: Quality of the service and effectiveness of service operations system are considered as important aspects of achieving the customers' satisfaction of any service organization. The goal of this research is to see how the quality of inland transportation services affects passenger happiness. The research was exploratory in nature, and factor analysis was utilized to determine the most important elements influencing passenger satisfaction with service quality. Passengers will be disappointed to learn that there is no canteen available. The rest of the launch terminal is in good shape. We also made some suggestions for improvements that would boost passenger happiness. Research methodology: SEM methodology has been extensively employed in research to study the causal links. SEM methodology has grown increasingly common in-service quality measurement study. It is hypothesized that socio-economic as well as launch service factors affect the maritime passenger vessel SQ. Results: This study makes empirical contributions to hospitality and tourism marketing literature especially in the way the ferry service can be upgraded. The results obtained via the definition of fuzzy number and linguistic level together with their membership functions as methods to measure service quality. The results also help the ferry company to better understand how the customers view their services. Limitations: During the data collection phase of this study, some unanticipated issues arose, causing the study to be postponed. The following are some of the issues: The personnel at the launch terminal were not particularly cooperative. Passengers and employees were uncooperative when it came to replying. Due to a time constraint, data for a single day was obtained; nevertheless, for an accurate data result, data for the entire year must be obtained. Contribution: The findings of this investigation will contribute to a better understanding of Launch SQ. The most crucial aspect is that it connects passenger demand to Launch SQ. Individual observations are used to generate the results in this thesis. The identification of key SQ variables that influence overall SQ can surely aid in improving SQ with low resources. The analysis yielded the following recommendations.
June 2, 2021
Deflection of Simply Supported Rectangular Plates under Shear and Bending Deformations Using Orthogonal Polynomial Function
Nwoji, C. U, Sopakirite, S, Oguaghamba, O. A, Ibeabuchi, V. T
Page Numbers : 98-103
DOI : 10.36348/sjce.2021.v05i05.001
Plates are common structural elements use in several engineering applications and are subjected to different types of loads, including acoustic excitations. The first satisfactory theory of bending plates is associated with Navier and later Kirchhoff. These theories nevertheless, are deficient as they do not take into account the influence of transverse shear forces on the deformation of plates. Consequently, this work explicitly established a refined plate equation, which considers the effect of shear deformation in line with Vasil’ev approach. The differential equation of plates with shear effect was solved for all edge simply supported (SSSS) condition subjected to uniformly distributed load using orthogonal polynomial method. Numerical solutions in the present study are compared to Navier’s solution based on Kirchhoff’s hypotheses which gives an insignificant percentage difference for membrane plates (-00.308% for h = 0.05m) and thin plates (00.260% for h = 0.15m). However, it is also observed that the percentage difference between the present study and Kirchhoff’s hypotheses is high for fairly thick plates (04.172% for h = 0.40m) due to incorporation of share deformation in the solution. The result presented shows good approximation for analyses of fairy thick and thick Isotropic rectangular plates.
May 20, 2021
The Modelling of Torque and Angular Speed with Time on Hammer by Lagrange Formula in Robotic Arm
Page Numbers : 94-97
DOI : 10.36348/sjce.2021.v05i04.004
Through modelling it is found that the torque value attains 4000Nm with arm and hammer speed of 0.6º/s and 0.05m/s respectively with including arm3 whilst the torque arrives 480Nm with 5º/s and the same hammer speed of 0.05m/s with kinetic energy of only hammer. The torque has been the least of 80Nm at 30º/s with one kinetic system. Meantime the one may be 620Nm at 4 º/s with two kinetic system. That means that the least torque is formed through the biggest speed and hammer kinetic system. For the cost declining the less torque may be adopted and for the security the bigger one may be chosen. In this paper the less one is a factor for the cost declining. It is found that the effect turn is angular speed being bigger than hammer speed. So we shall pay more attention to the former. The angular speed is smaller the torque is higher.
May 20, 2021
A Simulation between Torque and Angle with Speed on Five Freedoms of Robot Mechanical Arm in Multibody Systems
Run Xu, Boyong Hur
Page Numbers : 91-93
DOI : 10.36348/sjce.2021.v05i04.003
The effective factor has the turn of M1>M2>M3 in robotic arm. It has too turn 0.5m/s, 5º/s> 0.3m/s, 8º/s> 0.1m/s, 11º/s within conditions. That says that the speed is larger than angular speed about its effect to torque. The biggest torque happens at 5 º/s and 0.5m/s in first robot arm which is 1800Nm. The least one is at 11 º/s and 0.1m/s in the third robot one which attains 9Nm. The turn of effective torque is small angular speed and hammer speed. When the angular speed arrives 3º/s and hammer speed attains 0.5m/s the 3000Nm torque may be formed.
Original Research Article
May 18, 2021
Investigation of Index Properties of Soils along Jos-Makurdi Road in North Central Nigeria
Sule E, Maude EH, Adamu AY, Mailafiya BY
Page Numbers : 87-90
DOI : 10.36348/sjce.2021.v05i04.002
Index properties of soil forms part of the precondition for its use in civil engineering construction works. The neglect of it will give investors a wrong idea about the properties of the soil material. This research investigates the index properties of soils along jos-makurdi road in north central Nigeria. A trial pit was dug under four different bridges to a depth of 1m each and soil samples were collected by method of disturbed sampling and analyzed using the following tests: Moisture content test, Particle size distribution test, Atterberg limit test and Specific gravity test. All these tests were carried out according to procedure highlighted in BS1377 1990. By visual inspection Grey colours were observed of both soil sample SS1and SS2; while light brown and brownish colours were observed from SS3and SS4 respectively. The natural moisture content of the soil sample SS1, SS2, SS3 and SS4, are 6.56, 7.89. 52.52 And 54.72%. Using the unified soil classification system (USCS), the SS1 and SS2 were classified as well graded sand (SW) while SS3 as silt sand (SM) and SS4 was classified as clay sand (SC), respectively. The SS1 and SS2 were non-plastic while SS3 have liquid limit (LL) of 33.62%, plasticity index of 32.06% and linear shrinkage of 3.85%; and SS4 have liquid limit (LL) of 52.40%, plasticity index of 41.28% and linear shrinkage of 2.5%. The specific gravity (GS) obtained from the test results are 2.66, 2.65, 2.38 and 2.27, for SS1, SS2, SS3 and SS4 respectively. Based on the test results obtained from the study trial pits, SS1 and SS2 are well graded sand (SW) which is suitable for most engineering construction while silt sand (SM) and clay sand (SC) will require stabilasation or modification for possible use in engineering application. Based on these investigations, the index properties of the soil sample, SS1, SS2, SS3 and SS4 varies with the location.
Original Research Article
May 10, 2021
Statistical Modelling of Flexural Strength of Laterite-Quarry Dust Concrete
Anya C. U, Orji S. E, Enebe E. C
Page Numbers : 79-86
DOI : 10.36348/sjce.2021.v05i04.001
With the growing emphasis on sustainability, the construction industry is more interested in applying environmental friendly concrete in its construction projects. This paper developed model for predicting the 28th day flexural strength of laterite-quarry dust concrete using (5, 2) extreme vertices design of Minitab 17. Physical property test were conducted on the laterite and quarry dust and several trial mixes of concrete were carried out to determine the lower (Li) and upper bound (Ui) limit of each of the components. River sand was replaced with a maximum of 40% laterite and 60% quarry dust in the trial mixes. Several mix proportions were generated using the extreme vertices design. The design matrix consisted of fifteen (15) design points and seven (7) check points with replications of the vertices and the centroid, given a total of twenty eight (28) runs. Eighty four (84) numbers of laterite-quarry dust concrete beams of 600 x 150 x 150mm were prepared and tested for their flexural strength after 28 days of curing. A second degree polynomial was fitted to the data of the flexural strength test result and adequacy of the model was confirmed using the p-value, F statistics and normal probability plot. Several mix proportions were generated and their flexural strength obtained using the developed model. The minimum and maximum flexural strength predictable by the model are 2.44N/mm2 and 4.95N/mm2. The model can help predict the flexural strength of laterite-quarry dust concrete for both reinforced and non-reinforced concrete design for domestic and commercial constructions.