Now showing 1 - 10 of 40
  • Publication
    Effect of bolt configurations on stiffness for steel-wood-steel connection loaded parallel to grain for softwoods in Malaysia
    ( 2022) ;
    Francis Ting Shyue Sheng
    ;
    Abdul Razak Abdul Karim
    ;
    Marcin Nabialek
    ;
    ;
    Marek Sroka
    Steel-wood-steel connection is widely seen in many applications, such as timber structures. The stiffness of steel-wood-steel connection loaded parallel to grain for softwoods originated from Malaysia was investigated in this study. Numerical models have been developed in ABAQUS to study the stiffness connection. Softwoods of Damar Minyak and Podo have been selected in this analysis. The comprehensive study focused on the effect of bolt configurations on stiffness. Numerical analysis is carried out and the developed model has been validated with the previous study. Further investigations have been made by using the validated model. From this model, numerical analysis of the stiffness values have been made for various bolt configurations, including bolt diameter, end distance, bolt spacing, number of rows and bolts and edge distance. The result shows that the stiffness of bolted timber connections for softwood depends on the bolt diameter, number of rows and bolts, end distance and edge distance. Based on the result, stiffness increased as the diameter of the bolt, end distance, number of rows and bolts and edge distance increased. It is also discovered that the stiffness equation in Eurocode 5 (EC5) is inadequate as the equation only considered parameters which are wood density and bolt diameter. Other connection parameters such as geometry are not considered in the EC5 equation.
  • Publication
    Mechanical Properties of Concrete with Activated Sugarcane Bagasse Ashes as Cement Replacement
    ( 2022-01-01)
    Misnon N.A.
    ;
    Khairuddin F.H.
    ;
    Asri S.Z.M.
    ;
    ;
    Fikri R.
    ;
    Osmi S.K.C.
    Sugarcane bagasse waste is one of the biomass wastes generated in Malaysia. This study investigates the potential of the sugarcane bagasse waste to replace cement content in concrete mixtures by converting the bagasse waste into activated carbon ashes using physical activation method. The mechanical properties of sugarcane bagasse activated carbon concrete was carried out to determine the effectiveness of activated sugarcane bagasse ash (SBA) in the concrete mix by performing concrete hardened test i.e., compressive test, splitting tensile test and flexural test. The SBA replacement in concrete mixture showed a promising result and has a great potential to be pozzolan materials.
  • Publication
    Validation Of Shear Failure On Bolted Connection For Nyatoh Hardwood
    ( 2023-01-01)
    Ujan X.L.A.
    ;
    Karim A.R.A.
    ;
    Sa’Don N.M.
    ;
    Sahari S.H.
    ;
    ;
    Quenneville P.
    The lack of consideration of brittle failure by the Malaysian Timber Standard (MS544-5) in the design of bolted connections for local hardwood can be seen from the unacceptable under-design performance shown by the code. This makes the design output costly because of the increased use of steel materials due to either bigger bolt diameters or larger bolt quantities required. The current study was conducted to examine the effectiveness of the existing design equations for bolted connections in Nyatoh hardwood. This present study was to propose a set of optimised equations that can be used for the retrofit design of wall-diaphragm connections in unreinforced masonry buildings. The row shear failure observed in the tested bolted connections of Nyatoh hardwood was also reported. Ten different bolted connection configuration details in the manner of a steel-wood-steel arrangement were tested, which all had a single row bolted connection. By using the linear regression method in analysing the experimental data obtained, a calibration factor for optimising the Row Shear Model (RSM) equation was identified. From the comparisons made between the experimental results and the strength predictions given by both MS544-5 and RSM, it was found that the design strength calculated from MS544-5 was too conservative for predicting the bolted connection strength in Nyatoh hardwood, whereas the RSM predictions were acceptable and recommended.
  • Publication
    Effect of organic matter on pathogen population during composting of municipal sludge
    ( 2020-12-29)
    Hamzah N.
    ;
    Hashim N.F.
    ;
    Zainuddin N.S.
    ;
    Kassim J.
    ;
    Halip A.A.
    ;
    Population growth in Malaysia is expected to increase rapidly. Every sector of industry is expected to have a revolution including in agriculture sector. The utilization of organic fertilizer in agriculture as a green movement is to replace the chemical fertilizer subsequently, reduce the municipal sludge waste. Hence enhancing the growth and supply of nutrient to plant. However, the pathogenic growth in the final product is the greatest concerns. Thus, this study aims to evaluate the pathogen population in the compost of municipal sludge mixed with landscape waste for 90 days. The pathogen dynamic and its correlation with organic matter in 3 different ratios were analysed and recorded. The result showed that the pathogenic trends was uniformly increased at the early stage of composting and decreased gradually after reached the peak. R4 which comprises of equal ratio between municipal sludge and seed compost showed positive correlation with organic matter. R3 and R4 showed better removal of pathogen at maturity stage. Pseudomonas aeruginosa and Salmonella were failed to comply with the standard for R3 and only Salmonella failed for R4. This study supports the achievement of the Sustainability Development Goal (SDG) as an alternative way to combat the environmental issue by leveraging the usage of the waste produced for the purpose of the waste reduction and sustain the environment.
  • Publication
    Investigating the effect of steel wire and carbon black from worn out tyre on the strength of concrete
    ( 2024-10) ;
    Ali Naqiuddin Zamah Shari
    ;
    Nur Zakiah Anis Abdul Rahim
    ;
    ; ; ; ;
    György Deak
    Technology in concrete is rapidly developing to improve the quality and properties of concrete. One of the many recycled materials is worn-out tyres. Currently, the use of tires is very widespread considering the use of vehicles that increase from time to time. Piles of discarded tires can cause a lot of damage to the environment. So, by using steel wire waste (SWW) as new fiber reinforcement in concrete and with the combination with carbon black (CB), it is hoped that, by doing this, not only it could improve the quality of concrete, but also preserves the environment. Therefore, the objective of this research was, to identify the properties of fresh concrete with the addition of SWW and CB, and also to investigate the physical and mechanical properties of hardened concrete, incorporating of SWW as additional fiber reinforcement and CB. For fresh concrete, workability using a slump test was conducted. Several tests were carried out on the properties of hardened concrete. Among them were compressive strength, flexural strength, splitting tensile strength, and water absorption. The physical appearance of the concrete has also been examined and recorded. There are four batches of concrete which consist of one control batch and three batches of concrete with various weights of SWW which are in the portion of 300 g, 600 g, and 900 g, and the weight of CB is maintained at 300 g for all batches. For workability, all concrete batches with the addition of SWW and CB show acceptable workability. For the case of the density of fresh concrete, samples containing 900 g addition of SWW have the highest density which was 2520 kg/m³, as expected. Results for water absorption show that the lowest value is contributed by the control sample which was 7.6%. For compressive and flexural strength, 300 g addition of SWW has the highest value which was 28.52 MPa for compressive strength and 7.52 MPa for flexural strength. Lastly, for splitting tensile strength, the highest value was also obtained when 300 g addition of SW was added which was 5.4 MPa. To conclude, SWW and CB can be added to concrete to obtain comparable strength of concrete. However, some modifications could be made to both recycle materials to improve concrete performance.
  • Publication
    Indoor and outdoor particulate matter concentrations in the vicinity of plastic waste processing industries
    ( 2020-12-29) ; ;
    Wazam W.Z.
    ;
    Naidu D.
    ;
    Jamian R.
    While plastic recycling has gained conclusive acceptance by various stakeholders as a preferable products’ end-of-life management, plastic waste processing industries may contribute to serious air pollutants emission and impair human health, especially if it is in uncontrolled conditions. Apart from toxic gas pollutants, this industry may also emit significant concentration of particulates matter or dust, notably via physical (shredding, sorting, and washing) and melt (re-granulation and reprocessing) processes. Meanwhile, in Sungai Petani, Kedah, Malaysia, public anguish is increasing in recent years due to mushrooming plastic waste recycling industries in its residential area. Thus, a study was conducted to analyse the day- and night-time ambient air PM10 levels and their relationship with selected meteorological parameters (ambient temperature, relative humidity and wind speed) at two different locations (Cinta Sayang Resort Villa, CSRV and Metro Specialist Hospital, HM) in Sungai Petani, Kedah, Malaysia. The mean ambient PM10 levels of Cinta Sayang Resort Villa (CSRV) and Metro Specialist Hospital (HM) were found exceeding the New Malaysia Ambient Air Quality Standard at 150 µg/m3 (24-hours), which were 568.082 ± 266.441 µg/m3 615.046 ± 355.672 µg/m3, respectively. Distribution of PM10 concentrations betwen day and night-time were found to be statistically insignificant at both sites. Meteorological parameters have also contributed to the trend of PM10 concentrations at both sites especially at HM. Inverse correlation with PM10 at CSRV was explained by the absence of moisture (or rain) at the site while the positive correlation observed at HM was due to the hot temperature-strong wind association at the site. Temperature was found to be the manipulating factor for PM10 at HM, via linear regression model developed at PMouth = - 4352.426 + 170.557 × Th with F(1, 8) = 15.224 at p < .005, accounting for 65.6% of the variation Thus, proper attention should be given to the particulates matter emitted in Sungai Petani, believed to be influenced by the uncontrolled emission from the plastic recycling industries.
  • Publication
    Effect of bolt configurations on stiffness for steel-wood-steel connection loaded parallel to grain for softwoods in Malaysia
    ( 2022-01-01) ;
    Sheng F.T.S.
    ;
    Karim A.R.A.
    ;
    Nabialek M.
    ;
    ;
    Sroka M.
    Steel-wood-steel connection is widely seen in many applications, such as timber structures. The stiffness of steel-wood-steel connection loaded parallel to grain for softwoods originated from Malaysia was investigated in this study. Numerical models have been developed in ABAQUS to study the stiffness connection. Softwoods of Damar Minyak and Podo have been selected in this analysis. The comprehensive study focused on the effect of bolt configurations on stiffness. Numerical analysis is carried out and the developed model has been validated with the previous study. Further investigations have been made by using the validated model. From this model, numerical analysis of the stiffness values have been made for various bolt configurations, including bolt diameter, end distance, bolt spacing, number of rows and bolts and edge distance. The result shows that the stiffness of bolted timber connections for softwood depends on the bolt diameter, number of rows and bolts, end distance and edge distance. Based on the result, stiffness increased as the diameter of the bolt, end distance, number of rows and bolts and edge distance increased. It is also discovered that the stiffness equation in Eurocode 5 (EC5) is inadequate as the equation only considered parameters which are wood density and bolt diameter. Other connection parameters such as geometry are not considered in the EC5 equation.
  • Publication
    Effect of Effective Microorganisms (EM) on concrete performance
    Concrete technology is life-long research, that strives to discover the best additives or admixtures that are able to produce good concrete in terms of physical, chemical and mechanical properties in a more economical, sustainable, environmental friendly and obtainable. This study focuses the effect of different percentages of EM toward strength of concrete. The compressive strength test was carried out to analyse these properties by using the concrete cubes with size 100 mm x 100 mm x 100 mm. These concrete mixes were tested at different ages which are 7, 14 and 28 days. Effective microorganism (EM) replacement percentages are 5%, 10% and 15% and the strength of concrete with EM replacement will be compared with the control sample. All the cubes were cured by immersed in the water for curing process before the compressive strength tests were conducted. The finding shows that the workability degree of EM mixture is similar with the conventional mixture. The compressive strength increase with the increment of EM content. The results shows that 10% of EM could be the optimum value of water replacement in concrete production to improve strength and durability.
  • Publication
    Computer simulations of end-tapering anchorages of EBR FRP-strengthened prestressed concrete slabs at service conditions
    ( 2023)
    Chirawat Wattanapanich
    ;
    Thanongsak Imjai
    ;
    Reyes Garcia
    ;
    ; ;
    Andrei Victor Sandu
    ;
    Petrica Vizureanu
    ;
    Petre Daniel Matasaru
    ;
    Blessen Skariah Thomas
    This article examines numerically the behavior of prestressed reinforced concrete slabs strengthened with externally bonded reinforcement (EBR) consisting of fiber-reinforced polymer (FRP) sheets. The non-linear finite element (FE) program Abaqus® is used to model EBR FRP-strengthened prestressed concrete slabs tested previously in four-point bending. After the calibration of the computational models, a parametric study is then conducted to assess the influence of the FRP axial stiffness (thickness and modulus of elasticity) on the interfacial normal and shear stresses. The numerical analysis results show that increasing the thickness or the elastic modulus of the FRP strengthening affects the efficiency of the FRP bonding and makes it susceptible to earlier debonding failures. A tapering technique is proposed in wet lay-up applications since multiple FRP layers are often required. It is shown that by gradually decreasing the thickness of the FRP strengthening, the concentration of stress along the plate end can be reduced, and thus, the overall strengthening performance is maximized. The tapering is successful in reducing the bond stress concentrations by up to 15%, which can be sufficient to prevent concrete rip-off and peel-off debonding failure modes. This article contributes towards a better understanding of the debonding phenomena in FRP-strengthened elements in flexure and towards the development of more efficient computational tools to analyze such structures.
  • Publication
    Effectiveness validation on existing design equations for sustainable design of mansory building retrofits
    ( 2022-06-01)
    Ujan X.L.
    ;
    Karim A.R.A.
    ;
    Sa’Don N.M.
    ;
    Yao T.X.
    ;
    Quenneville P.
    ;
    Due to the unsatisfactory performance of MS544-5 in estimating the design capacity of bolted timber connections, this present study was initiated to validate the existing predictive equations used by the Malaysian Standard (MS544-5). An evaluation of the European Yield Model (EYM) equation was also done to provide an optimal design equation for the bolted connection design in local hardwood. To verify these two sets of equations, a series of bolted timber connection tests was conducted on Nyatoh hardwood. Nyatoh was chosen as its strength makes it ideal for use as structural timbers, either as roof rafters or floor joists in masonry building constructions. The bolted timber connection tests conducted involved eight types of bolt configurations and the tests on each configuration was done in sets of 10 specimens. The experimental values obtained were then compared with the predictive equations of MS544-5 and EYM to examine their effectiveness. From the comparison, it was found that the prediction values given by MS544-5 were overly conservative with an average effective ratio of 0.34 while the EYM had an average effective ratio of 1.09. Thus, the use of EYM equations was recommended for the sustainable retrofit design development of Malaysian masonry buildings