Numerical modelling and validation of light gauge steel top-seat flange-cleat connection

This paper presents the numerical investigation on the moment-rotation behaviour of cold-formed top-seat flange-cleat connection, a type of light gauge steel connection which structural connection has sparked a wide range of research interest. The cold-formed channel sections were assembled back-to-back to form I-shape beam and column members. Two components were used to connect the members, notably the 2 mm cold-formed bracket and the 6 mm hot-rolled angle. The results were collected from different beam depths, namely 150 mm, 200 mm and 250 mm. The rotational stiffness and strength obtained from the numerical modelling were then compared with design requirements from BS EN 1993-1-8 and experimental data. The comparison showed not more than 35 % difference in strength and about 50 % difference in rotational stiffness between numerical modelling and experimental data. However, there was a noticeable difference between finite element models and analytical calculation. The differences were from 18 % to 66 % for strength and between 1 % and 145 % for stiffness. Finite element models showed a better agreement with experimental data as compared to analytical study. Edge stiffener of numerical model and theoretical stiffness calculation had caused significant difference in comparison

Parametric Study of Fire Performance of Concrete Filled Hollow Steel Section Columns with Circular and Square Cross-Section

Concrete filled hollow steel section column have been widely accepted by structural engineers and designers for high rise construction due to the benefits of combining steel and concrete. The advantages of concrete filled hollow steel section column include higher strength, ductility, energy absorption capacity, and good structural fire resistance. In this paper, comparison on the fire performance between circular and square concrete filled hollow steel section column is established. A threedimensional finite element package, ABAQUS, was used to develop the numerical model to study the temperature development, critical temperature, and fire resistance time of the selected composite columns. Based on the analysis and comparison of typical parameters, the effect of equal cross-sectional size for both steel and concrete, concrete types, and thickness of external protection on temperature distribution and structural fire behaviour of the columns are discussed. The result showed that concrete filled hollow steel section column with circular cross-section generally has higher fire resistance than the square section

Factors Contributing to the Presence of Depression in an Online Distance Learner: A systematic review

Studies show that online learners are depressed when committing themselves to online learning. However, little data are available about the factors that contribute to the presence of depression. This study aims to reveal the factors by conducting a systematic literature review on six online databases. Based on the review, this study has found that the factors could be categorised into poor perception of online learning mode, infrastructure, resources and support issues, personal weakness and problem, and the COVID-19 phenomenon. Given the findings, the COVID-19 phenomenon interestingly seemed to be the main factor and should be further investigated in the future. Keywords: Depression; Online learner; COVID-19; eISSN: 2398-4287 © 2022. The Authors. Published for AMER ABRA cE-Bs by E-International Publishing House, Ltd., UK. This is an open-access article under the CC  BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under the responsibility of AMER (Association of Malaysian Environment-Behavior Researchers), ABRA (Association of Behavioral Researchers on Asians), and cE-Bs (Centre for Environment-Behavior Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia

Identifying Pertinent Elements of Critical Thinking and Mathematical Thinking Used in Civil Engineering Practice in Relation to Engineering Education

Engaging critical thinking and mathematical thinking in solving engineering problems is a way of approaching the engineering criteria of Engineering Accreditation Council, Board of Engineers Malaysia. Thus, it is timely and crucial to inculcate the critical thinking and mathematical thinking into the current engineering education. Unfortunately, information about these two modes of thinking in real-world engineering practice is found lacking in the literature. Therefore, this paper focuses on explaining an analytic process in identifying pertinent elements of critical thinking and mathematical thinking used in real-world civil engineering practice. The analytic process, namely open coding is a part of coding process in modified grounded theory analysis. Data consist of semi-structured interviews with eight practicing civil engineers from two different consultancy firms. A total of fifty three pertinent elements emerged during the analytic process. The selection of these pertinent elements was based on the predominant pattern and frequency of the informants and open codes. The pertinent elements were eventually integrated to develop a substantive theory. The substantive theory provides useful information for the engineering education

Analytical Model of Nonlinear Semi-rigid Frames Using Finite Element Method

Performance-based design for a constructional steel frame in nonlinear-plastic region requires an improvement in order to achieve a reliable structural analysis. The need to explicitly consider the nonlinear behaviour of structures makes the numerical modelling approach much more favourable than expensive and potentially dangerous experimental work. The parameters considered in the analysis are not limited to the linear change of geometry and material yielding, but also include the effect of large deformations, geometrical imperfections, load eccentricities, residual stresses, strain-unloading, and the nonlinear boundary conditions. Such analysis requires the use of accurate mathematical modelling and effective numerical procedures for solving equations of equilibrium. With that in mind, this paper presents the mathematical formulations and finite element procedures of nonlinear inelastic steel frame analysis with quasi-static semi-rigid connections. Verification and validation of the developed analytical procedures are conducted and good agreements are obtained. It is an approach that enables the structural behaviour of constructional steel frames to be traced throughout the entire range of loading until failure. It also provides information on the derivation of the structural analysis by using finite element method

Tourists' Perspectives on Condition of Heritage Buildings and Resiliency of the Heritage Tourism Industry in Melaka

Heritage buildings have been seen as an asset that needs to be maintained not only for the sake of history and culture but also as a legacy for future generations. In Melaka, heritage buildings have become a source of pride for the people of Malacca and also the main source of income for the state government through heritage tourism activities. It is important to ensure that these heritage buildings continue to recover and be free from damage so that the tourists who come have a good experience. This study is focused on the issues which were concerning the condition of heritage buildings in Malacca from the perspective of tourists. Heritage buildings around the tourist spot in Malacca were selected as locations for this study. The study adopted a questionnaire survey, that involved 211 local tourists as the respondents of the survey. The respondents were requested to gauge the conditions issue and the resiliency of heritage buildings using 5-points Likert scale. The collected data were analysed descriptively. The results found that the overall average condition issue mean value is high (M = 4.05) and can be interpreted as satisfactory. This indicates that the level of satisfaction with the condition received is high. Although most respondents expressed a good experience with the condition of the heritage buildings that they had visited, there is still room for improvements. The findings also show that all the agreement statements related to the resiliency of the heritage tourism industry in Melaka have an average score of 79%. As a result of the survey, it is important that the parties involved in heritage management follow the conservation standards, promote, and practice good integrity, especially in ensuring the originality and authenticity of materials used as well as good work procedures to ensure the future resiliency of the heritage tourism industry in Malacca

A tool to measure engineering students' design strategies and abilities

Malaysia is moving from service-based industries to knowledge-based industries to achieve Vision 2020. This is also in line with innovation-led economy and globalization. Hence, there is a pressing need to transform the current engineering education system to meet the ever-growing roles and responsibilities of contemporary engineers. Design is central to engineering activity because students can apply the theoretical knowledge into practice. Students' engineering design knowledge and abilities are unknown when they enroll into the engineering programs. These engineering programs are either too low or too advanced for the students' design abilities. Hence, dropout rates in the engineering programs escalate each year. The invention is an online questionnaire which will assist in determining students' engineering design knowledge and abilities. It will guide engineering faculties in identifying suitable candidates for their engineering program through the scores obtained by the students. The scores will determine the students' level of engineering design knowledge. This will function as a mechanism for the faculties to filter the candidates' knowledge of engineering design and reduce the number of dropouts from the engineering program

Maximum Power Point Tracking Charge Controller for Standalone PV System

The depletion of conventional energy sources and global warming has raised worldwide awareness on the usage of renewable energy sources particularly solar photovoltaic (PV). Renewable energy sources are non-polluting sources which can meet energy demands without causing any environmental issues. For standalone PV systems, a low conversion efficiency of the solar panel and high installation cost due to storage elements are the two primary constraints that limit the widespread use of this system. As the size of the system increases, the demand for a highly efficient tracking and charging system is very crucial. Direct charging of battery with PV module will results in loss of capacity or premature battery degradation. Furthermore, most of the available energy generated by the PV module or array will be wasted if proper tracking technique is not employed. As a result, more PV panels need to be installed to provide the same output power capacity. This paper presents selection, design and simulation of maximum power point tracker (MPPT) and battery charge controller for standalone Photovoltaic (PV) system. Contributions are made in several aspects of the whole system, including selection of suitable converter, converter design, system simulation, and MPPT algorithm. The proposed system utilizes direct duty cycle technique thus simplifying its control structure. MPPT algorithm based on scanning approach has been applied by sweeping the duty cycle throughout the I-V curve to ensure continuous tracking of the maximum power irrespective of any environmental circumstances. For energy storage, lead acid battery is employed in this work. MATLAB/Simulink® was utilized for simulation studies. Results show that the propose strategy can track the MPPs and charge the battery effectively

Temperature rise of cold-formed steel built-up back-to-back column under standard fire

Cold-formed steel (CFS) has been used for various applications in building structure. Due to its many advantages, the uses of CFS can be widened to build new or to renovate existing single one or two families private homes. However, the fire resistance of the CFS is a critical issue whereby inclined to lose its vigour when it is exposed to fire, compared to hot-rolled steel member. This study takes the opportunity to investigate the application of this material as column members subjected to the standard fire. Four columns were tested. One column with a static load was tested under the ambient condition, while the three other columns were loaded at different degrees of utilisation under the standard ISO 834 fire conditions. The increases of temperature on the column surface were monitored using thermocouple Type K and the analyses of this thermocouple reading was taken to evaluate the mean temperature of the column. The temperature behaviours of back-to-back column for all degrees of utilisation showed that, the web was a lower temperature compared to the flange due to the greater thickness of the web. Meanwhile, the failure temperature of the CFS could reach up to 651.0 ºC for 30.0 % degree of utilisation with 8.0 minutes of resistant time