bluuebunny/crossref_metadata_2025 huggingface dataset:
DETERMINATION OF PLASTIC LIMIT OF SOIL USING MODIFIED METHODS
Authors: A Rashid Ahmad Safuan , Katimon Ayob , Md Noor Norhazilan
Published: December 2024

Plastic limit is an important property of fine-grained soils. The standard thread-rollingmethod for determining the plastic limit has long been criticized for requiring considerablejudgments from the operator. This study was conducted to seek for a new method on thedetermination of the plastic limit in a way to overcome the inconsistence result produce by usingthe standard thread-rolling method. Four different methods were tested. The first method was the modified fall cone method, a method commonly used to obtain a liquid limit. The second method was the rolling device method which is previously proposed by Bobrowski and Griekspoor (1992). The third method was proposed by Wood and Wroth (1978) using a heavier cone. The fourth method was the one proposed by Tao-Wei Feng (2004) which made use of a small soil container. Eight soil samples representing plasticity index (PI) ranging from 15 to 42% were tested. The results indicated that the correlation factor between the standard methods and the suggested methods were in the range 0.72 and 0.99. Regarding to the regression analysis result, the first method is more comparable to the standard thread method.
EXPERIMENTAL INVESTIGATION ON BEHAVIOUR OF CROSS-FLOW THERMAL EFFLUENT DISCHARGE IN FREE SURFACE FLOW
Authors: Ibrahim Zulkiflee , Abdul Latiff Abd. Aziz , Hashim Noor Baharim , Halim Herni , Mokhtar Kamal Nurul Hana , Haron Nuryazmeen Farhan
Published: December 2024

Thermal discharges such as from power stations or industries into rivers causing degradation of water quality. A study was conducted in the laboratory to investigate the changes of the ambient temperature caused by thermal effluent discharged into the flow. A crossâ€“flow thermal effluent is discharged from the bed of the channel. Thermal effluent flow rates of 0.133 liter/s and 0.05 liter/s and ambient flow rates of 20 liter/s and 10 liter/s were used in the study. Observation of thermal mixing process in the channel is concentrated in the near-field zone. The thermal dispersion patterns were observed along the channel through the isothermal lines; while the changes of ambient temperature are studied from the experimental data. The results indicate that the temperature changes are drastic in the near-field mixing zone. Then it gradually reduces along the channel until reaches the far-field mixing zone. Lower layer of the flow experiences high excess temperature compared to middle and upper layers of the flow. Meanwhile, larger effluent flow rate produces higher excess temperature in the receiving water body than small effluent flow rate. Based on experimental data, equations of excess temperature and dispersion were established.
FINDING OF COEFFICIENTS AND OXIDIZABLE NITROGEN FROM PALM OIL MILL EFFLUENT (POME) FOR ACTIVATED SLUDGE MODELS (ASMS)
Authors: A. Damayanti A. Damayanti , Salim Mohd Razman , Ujang Zaini
Published: December 2024

Activated Sludge Models (ASMs) have been widely used as a basis for further model development in wastewater treatment processes. Values for parameters to be used are vital for the accuracy of the modeling approach. The objective of this study is to determine coefficients of the system, and oxidizable nitrogen of palm oil mill effluent (POME). A continuous stirred tank reactor (CSTR), with continuous flow for 20 hours, was used in this study. The DO profile for 11 days was monitored. The total, soluble, insoluble COD and soluble ammonia nitrogen were measured at the beginning and end of the experiment. Also, the coefficients and oxidizable nitrogen fractions are determined.
GEOSTATIONARY METEOROLOGICAL SATELLITE-BASED QUANTITATIVE RAINFALL ESTIMATION (GMS-RAIN) FOR FLOOD FORECASTING
Authors: Tahir Wardah , Ibrahim Zaidah , Ramli Suzana
Published: December 2024

The consequences of global warming include changes in rainfall patterns and increase in flood risks or droughts. The frequent unexpected climate change phenomena, especially the severe flood occurrences, necessitate improvements in the related weather monitoring instruments and techniques. The rain measuring system, whether the conventional rain gauges or the more advanced Remote Sensing and Transmission Unit (RSTU) panel, can only be sparsely installed at suitable location, hence they are considered as point rain measurement. The paper introduces an innovation to point rain estimation, named GMS-Rain, which estimates convective rainfall using information from the Geostationary Meteorological Satellite-5 (GMS-5) infrared (IR) images and numerical weather prediction (NWP) products in an Artificial Neural Network model. Although the estimates are indirect, meteorological satellites with fine temporal and spatial resolution cover broader areas that may be inaccessible or that may cause difficulties with the traditional rainfall measurement such as the deep forests, large water bodies or rigid mountains, therefore should be taken as complementary to rain gauge or radar measurements. In addition, the rain estimation from the observation of cloud development would enable earlier forecast of critical storm events. The GMS-Rain model is also a potential input to a hydro-meteorological flood forecasting system with an improved lead time of warning. Rainfall estimates from the GMSRain are validated against previously recorded hourly and total accumulated Thiessen arealaveraged gauged rainfall values with coefficient correlation values of 0.63 for 0.91 respectively, while an extra lead time of around 2 hours is gained when the model is coupled with a rainfallrunoff model to forecast a flood event in the upper Klang River Basin.
PREDICTION OF CO2 CORROSION GROWTH IN SUBMARINE PIPELINES
Authors: Yahaya Nordin , Md Noor Norhazilan , Mat Din Mazura , Mohd Nor Shadiah Husna
Published: December 2024

The paper presents a probabilistic-based methodology for the assessment of a pipeline containing internal corrosion defects. Two different models have been used to predict the future CO2 corrosion rates namely a linear growth and the deWaard-Milliams models. A probabilistic approach is used to analyse the behaviour of corrosion data obtained from in-line intelligent (ILI) pigging inspections. The outcomes are parameters represented by their corresponding statistical distribution. Due to the availability of these statistical parameters, a Monte Carlo simulation is used to calculate the probability of failure of the pipeline due to bursting failure. The existence of corrosion may reduce the maximum capacity of the pipe, as such causing leakage and bursting when the operational pressure supersedes its threshold. From the analysis of the result, failure probability based on theoretical linear growth model exhibit slightly longer lifetime of the pipeline with three years interval compared to deWaard-Milliams model. This is due to higher mean value of corrosion growth rate estimated using the empirical deWaard-Milliams model. Both results are very useful in prolonging the lifetime of pipelines by having knowledge of the past to schedule the future maintenance work.
RIPPABILITY CLASSIFICATION FOR QUARTZITE BASED ON SPECIFIC ENERGY AND FIELD PRODUCTION RATE
Authors: Mohd Amin Mohd For , Sook Huei Chan , Md Rafik Abdul Ghani
Published: December 2024

When rock is deemed to be rippable, it is essential to classify how difficult to actually rip this rock on site. The rating on the difficulty is termed as rippability classification, and it is based on mass and material properties of the rock which contribute to its resistance against ripping. This paper highlights a study to establish a similar classification for quartzite which is based on specific energy (SE) and field production rate (Qr). To facilitate in analysis of data, the study area (located in Dengkil, Selangor) is divided into 6 panels (A to F). Collected data are grouped according to these panels. Laboratory assessments include verification on cuttability and strengths of the rock samples. Seismic survey and in situ ripping test were field appraisals conducted to assess rippability of the in situ quartzite. Analysis of data indicates that besides its material properties, rippability of quartzite can be evaluated using its SE. Ranging between 3.19 and 6.19 MJ/m3 , the SE is related to the Qr, which is between 147 and 292 m3 /hr. For the six panels investigated, it is found that the higher the SE, the lower is the Qr (i.e. more difficult to rip). Based on the SE, Qr and horsepower of ripper dozer, rippability classification for the quartzite is established. This classification is essential for planning and costing of major earthworks, particularly in estimating capacity of ripper dozer and duration of earthwork.
DETERMINATION OF MERCURY IN ENVIRONMENTAL SAMPLES IN MUAR RIVER ESTUARY
Authors: Rahman Md. Mokhlesur , Hui Ling Kho , Kasim Zaleha , Wan Nik Wan Sani
Published: December 2024

This study was carried out at the Muar River Estuary, Johore, Malaysia. Water samples, sediment and biota that are Crassostrea iredalei, Perna viridis and Anadara granosa were collected during monsoon season in November 2005. All the samples were analyzed for the mercury concentration by using cold vapor atomic absorption spectrophotometer (CV-AAS). The temperature was between 28.70Â°C to 29.83Â°C, salinity at 12.78-29.96 ppt, dissolved oxygen at 5.0-6.83mg/L and pH at 6.71-7.93. The report of water samples show that the dissolved mercury in water samples was between 0.271Âµg L-1 and 0.8261tg L-1 while the total mercury in sediment was between 0.560-3.513Âµg g-1 dry weights. For biological sample, the average concentration of mercury in Crassostrea irredelei was 1.854 Â± 1.012 Âµg g -1 . Perna viridis was 0.366 Â± 1.125 Âµg g-1 and Anadara granosa was 1.178 Â± 1.182 Âµg g-1 . The water at Muar River Estuary is still in safety level of mercury but biota especially Crassostrea irredelei and Anadara granosa are not safe to be taken due to the total mercury concentration was exceeding (WHO) level of 0.5 Âµg g-1 .
DURABILITY PERFORMANCE OF NATURAL RUBBER LATEX MODIFIED CONCRETE
Authors: Ismail Mohammad , Muhammad Bala , Mohamad Nur Aiza
Published: December 2024

Deterioration of concrete due to chemical aggression normally through transporting agents is a serious menace to the two major qualities of concrete; strength and durability. This paper reports the findings of a study conducted to assess the effect of natural rubber latex on resistance to the ingress of sodium sulphate (Na2SO4) and moisture into hardened concrete. Two principal categories of concrete (normal and modified) involving different grades and sizes were developed. Concentrated natural rubber latex was used in this study. The quantity of the latex was varied from 0 â€“ 5% and 0 â€“ 10% latex/water ratio (L/w) for the chemical resistance and water absorptions respectively. A simulated aggressive medium containing 2.5% Na2SO4 serves as the curing environment for the chemical detections. Results have shown that attack due to Na2SO4 and moisture absorptions are seriously influenced by the amount of latex added into the mix and period of exposure. It is further comprehended that the general moisture ingress is significantly affected by concrete grade. In fact, within the time frame considered in this work, the optimum amount of concentrated latex for maximum resistance to Na2SO4 penetrations is 1.5% (L/w) while for minimum water absorption is 5% (L/w). The outcome of the work therefore, identifies and indicates the level of efficiency and importance of using appropriate quantity of latex concentrate in the modification process of normal concrete, especially in the areas of sulphates attack and water ingress.
GEOSTATIONARY METEOROLOGICAL SATELLITE-BASED QUANTITATIVE RAINFALL ESTIMATION (GMS-RAIN) FOR FLOOD FORECASTING
Authors: Tahir Wardah , Ibrahim Zaidah , Ramli Suzana
Published: December 2024

The consequences of global warming include changes in rainfall patterns and increase in flood risks or droughts. The frequent unexpected climate change phenomena, especially the severe flood occurrences, necessitate improvements in the related weather monitoring instruments and techniques. The rain measuring system, whether the conventional rain gauges or the more advanced Remote Sensing and Transmission Unit (RSTU) panel, can only be sparsely installed at suitable location, hence they are considered as point rain measurement. The paper introduces an innovation to point rain estimation, named GMS-Rain, which estimates convective rainfall using information from the Geostationary Meteorological Satellite-5 (GMS-5) infrared (IR) images and numerical weather prediction (NWP) products in an Artificial Neural Network model. Although the estimates are indirect, meteorological satellites with fine temporal and spatial resolution cover broader areas that may be inaccessible or that may cause difficulties with the traditional rainfall measurement such as the deep forests, large water bodies or rigid mountains, thereforeshould be taken as complementary to rain gauge or radar measurements. In addition, the rain estimation from the observation of cloud development would enable earlier forecast of critical storm events. The GMS-Rain model is also a potential input to a hydro-meteorological flood forecasting system with an improved lead time of warning. Rainfall estimates from the GMSRain are validated against previously recorded hourly and total accumulated Thiessen arealaveraged gauged rainfall values with coefficient correlation values of 0.63 for 0.91 respectively, while an extra lead time of around 2 hours is gained when the model is coupled with a rainfallrunoff model to forecast a flood event in the upper Klang River Basin.
DETERMINATION OF CORROSION INITIATION OF REBAR IN CONCRETE BY MONITORING HALF-CELL POTENTIAL
Authors: G. M. Sadiqul Islam G. M. Sadiqul Islam , Sugiyama Takafumi
Published: December 2024

Corrosion of rebars in concrete is a key mechanism which determines the durability and service life of concrete structure. Half-cell potential of rebars in concrete subjected to a NaCl solution of 10% in the concentration has been monitored using embedded reference electrode in the concrete and computer operated automatic data acquisition system. A portable corrosion meter was also employed to measure half-cell potential and AC impedance. Initiation of corrosion in rebars were estimated by the former system and verified by the later. Corrosion initiation period was found to be from as early as 119 days and up to 360 days of chloride application depending on the characteristics of test specimens. Upon successful detection of corrosion initiation threshold chloride concentration for corrosion initiation was estimated. The estimated chloride threshold level for deformed rebar was found almost half of that with ideal plain steel rebar. Corrosion was spread over rebars depending on its surface characteristics.
A STUDY ON FLEXURAL MODULUS AND DUCTILITY OF LAMINATED CEMENTITIOUS COMPOSITES
Authors: Hossain Md. Zakaria , A.S.M. Abdul Awal A.S.M. Abdul Awal
Published: December 2024

This paper presents a new approach for flexural modulus of laminated composites derived from the analysis of a flexural-section composed of several ductile and brittle layers of different moduli. The derivation is based on the assumption that the tension and compression zones of the laminated composite are symmetrical with respect to the neutral axis and thus, half of the section is needed to analyze for complete derivation of flexural modulus of the whole section. This composed of two ductile layers of higher moduli providing in both tension and compression zones to maintain the equilibrium conditions during flexure. The formulation shows that the flexural modulus of the entire section of laminated composites obtained by this method is equal to the modulus of ductile layers plus a factor of the difference of modulus of ductile and brittle layers. It is concluded that this factor is different from the usual one which is obtained under uniaxial loadings. Despite the fragile nature of brittle layers of the composite, it has been found that the inclusion of two ductile layers into the laminated cementitious composites makes it fully ductile material owing to the synergetic action between the layers of two components.
EFFECTS OF CLAY AND MOISTURE CONTENT ON SOIL-CORROSION DYNAMIC
Authors: N. Yahaya N. Yahaya , K.S. Lim K.S. Lim , N.M. Noor N.M. Noor , S.R. Othman S.R. Othman , A. Abdullah A. Abdullah
Published: December 2024

Soil corrosion is a serious threat to the integrity of buried structures such as underground storage tanks, oil and gas transmission pipelines, and many other structures. This paper investigates the effects of soil engineering properties towards metal loss of buried X70 carbon steel coupons. The study focuses on soil engineering properties which are soil clay and moisture content. A number of 160 pieces of X70 carbon steel coupon were installed underground in five different locations in Peninsular Malaysia for 12 months period to study the influence of the above mentioned parameters towards metal loss caused by soil-corrosion. The samples were retrieved every 3 months to determine its weight loss and corrosion growth rate over time. The result shows that the rapid growth of corrosion is relatively correlated with the high moisture content of soil. Yet, corrosion initiated at a slow rate for clayey soil. Soil moisture content was found more influential towards corrosion dynamic as compared to clay content based on the qualitative evaluation.
STRESS-STRAIN BEHAVIOUR OF COMPLETELY DECOMPOSED GRANITE IN BOTH TRIAXIAL AND PLANE STRAIN CONDITIONS
Authors: Md.Kumruzzaman Md.Kumruzzaman , YIN Jian-Hua
Published: December 2024

Most of the field problems in geotechnical engineering are in three dimensional states or close to a plane strain condition. Strength and deformation properties of soils in plane strain condition are considerably different from those in an axisymmetric condition. Many researchers have investigated the behaviour of soils under a plane strain condition. However, most of the previous studies have concentrated on sedimentary type of soils like sand and clay. Our understanding on the plane strain behaviour for residual soils is less than that for sedimentary soils. A true triaxial system with four sliding rigid-plates and real time feedback control has been used to test specimens of a completely decomposed granite (CDG) soil (a residual soil) under plane strain condition. The setup of the true-triaxial rigid plates is briefly introduced first. The preparation of soil specimens and testing procedures are described. The basic properties of the CDG are presented. The stress-strain and strength behaviour of the soil obtained under plane strain condition was investigated, and compared to the behaviour obtained under axisymmetric loading conditions. The results reveal that the critical state line in q-pâ€² space obtained under plane strain condition is the same as that under axisymmetric condition. However, the critical state line in e- ln pâ€² space obtained under undrained plane strain condition is different from that under axisymmetric condition. The peak friction angle for plane strain tests is higher than that from axisymmetric loadings. It is also found that shear bands occur only in drained plane strain compression. Defuse bulging is the mode of failure for undrained plane strain as well as triaxial loading.
MICROZONATION MAPS FOR KUALA LUMPUR AND PUTRAJAYA
Authors: Marto, A. Marto, A. , Adnan, A Adnan, A , Hendriyawan Hendriyawan , Irsyam, M Irsyam, M
Published: December 2024

Geotechnical factors often exert a major influence on damage patterns and loss of life in earthquake events. Even within an area of a city, building response and damage are varied significantly due to variation of soil profiles in that particular city. The existing codes or provisions, which were applied in a certain region, may not be necessarily employed directly in other region since individual region has its own characteristics. Therefore, it would be necessary to perform seismic hazard analysis for each region and to develop seismic design code that is suitable with the characteristics of that particular region rather than adopting the existing code. This paper presents the results of microzonation study for Kuala Lumpur city center and Putrajaya in Peninsular Malaysia. The microzonation study consists of two stages: (1) determination of the local geological and local geotechnical site conditions; and (2) computation of the ground response through soil deposit from base rock motions. Ground response analyses were performed using one dimensional shear wave propagation method. The analyses were conducted using nonlinear approach in order to consider the actual nonlinear response of a soil deposit. The results show that the accelerations at the surface of Kuala Lumpur city center are in the range of 90 to 190 gals and 180 to 340 gals for 500 and 2,500 years return periods, respectively. The accelerations at the surface of Putrajaya are in the range of 130 to 190 gals and 220 to 340 gals for 500 and 2,500 years return periods, respectively. Generally, the amplification factors on each city for those two hazard levels, ranges between 1.2 and 2.6. As a conclusion for this study, eight microzonation maps have been produced for each city that could be used as input for seismic design, land use management, and estimation of potential liquefaction and landslides.
ASSESSMENT OF BUILDINGS FOR SEISMIC RESISTANCE
Authors: Sambu Potty Narayanan , Sirajuddin, M Sirajuddin, M
Published: December 2024

The recent earthquakes in India and different parts of the world have caused loss of human lives and damage to property due to the collapse of structures. Though an earthquake cannot be prevented, the loss of life and property can be minimized by taking necessary steps on the existing structures to reduce the damages. The seismic codes contain provisions for planning and designing earthquake resistant structures. It becomes essential to carry out a survey and identify existing structures that are deficient and carry out appropriate retrofit. This study first identifies the earthquake resistant features stipulated by the seismic codes for buildings. Then a survey assessment carried in the district of Kollam (Kerala, India) is reported. Kollam is in moderate seismic risk zone, in the seismic zone map prepared by the Bureau of Indian Standards. This city deserves attention owing to high concentrations of population. Each area differs from one another in terms of climate, culture, methods of construction and living standards. Materials used for construction also differ. The localized survey has found out the methods of construction, materials used for construction and general pattern of the structures in Kollam city. Structures that are prone to damage during a seismic event were identified. Recommendations are given based on the guidance available in seismic codes and other references for retrofitting such structures.
FIELD ASSESSMENT OF ROCK STRENGTH BY IMPACT LOAD TEST
Authors: Mohamad Edy Tonnizam , Gofar Nurly , Mohd Amin Mohd For , Mohd Isa Mohamed Fauzi
Published: December 2024

This paper introduces a new testing method for field determination of Index strength of rock mass. The method was developed as an alternative test in cases when difficulties were encountered by conventional Schmidt Hammer to determine the index strength of weak or weathered rock. This note explains the basic concept and the procedure of impact load test as an alternative way to determine the index strength of weak or highly weathered rock. A standard chart was developed for interpretation of impact load test through verification study on weathered granite.
MONITORING CORROSION OF REINFORCEMENT BAR USING CAPACITIVE SENSOR AT DIFFERENT CONCRETE COVER DEPTH
Authors: Abdul Rahman Siti Fatimah , Ismail Mohammad , Muhammad Bala , Md Noor Norhazilan , Bakhtiar Hazri
Published: December 2024

Corrosion of reinforcement is a worldwide problem that affects durability and integrity of reinforced concrete structures. Repairing deteriorated reinforced concrete structures at an advanced stage is very costly and time consuming. It is more advantageous if corrosion can be detected at an earlier stage so that some preventive measures can be carried out. Monitoring of reinforcement corrosion in concrete can be achieved by embedding corrosion sensor within the concrete cover. In this study, an Embedded Capacitor Sensor (ECS) was developed to evaluate corrosion activity in concrete specimen. ECS was embedded in the concrete and its function is to measure the corrosion potential (Ecorr) of reinforcement. Ecorr measured by ECS is a result of the accumulated positive and negative charges between the two ECS plates from the corrosion process. For actual testing, ECS was tied to the reinforcement and embedded in concrete specimens. It was then calibrated using standard portable sensor (Ag/AgCl reference electrode) by measuring Ecorr. The ECS measurement is proven reliable because the reading pattern was similar to what shown by standard portable sensor. For monitoring, the ECS also was tied to the reinforcement and embedded in concrete at two different depths (15 mm and 25 mm). The concrete specimens were contaminated with 5% NaCl by weight of cement and then immersed in 3.5% NaCl solutions at room temperature to speed up the corrosion process. From this research, it was found that Ecorr for 15 mm concrete cover is higher than 25 mm concrete cover. Thicker cover delay the penetration chloride ion and oxygen to the reinforcement. Eventually, the bars were found corroded from the broken specimens that confirmed the detection of corrosion activities as recorded by the sensors.
AUTO-CALIBRATION OF DAILY AND HOURLY TANK MODELâ€™S PARAMETERS USING GENETIC ALGORITHM
Authors: King Kuok Kuok , Harun Sobri , Chiu Po-Chan
Published: December 2024

The only calibration method for Hydrologic Tank model in early days is using trialand-error. This method required much time and effort for obtaining better results since a large number of parameters need to be calibrated. Therefore, various Global Optimization Methods (GOMs) have been applied to optimize Tank model parameters automatically. In this study, genetic algorithm was introduced to auto-calibrate daily and hourly Tank model parameters. The selected study area is Bedup Basin, Samarahan, Sarawak, Malaysia. Input data used for both daily and hourly model calibration are rainfall and runoff only. The accuracy of the simulation results are measured using Coefficient of Correlation (R) and Nash-Sutcliffe Coefficient (E2 ). The robustness of the model parameters obtained are further analyzed by boxplots analysis. Peak errors are also evaluated for hourly runoff simulation. Results show that GA method is able to obtain optimal values for ten parameters fast and accurate within a multidimensional parameter space that could provide the best fit between the observed and simulated runoff.
EFFECT OF HRT AND INFLUENT SUBSTRATE CONCENTRATION ON NUTRIENT REMOVAL AND MICROBIAL COMMUNITY DYNAMICS IN AN ANOXIC/ANAEROBIC-AEROBIC MBR
Authors: Ahmed Zubair , Ahn Kyu-Hong
Published: December 2024

In this study, effects of hydraulic retention time (HRT) and influent COD concentration on biological nutrient removal and changes in microbial community structure in an Membrane bioreactor (MBR) based system were investigated. Three different levels of CODinf and three HRTs (4, 5 & 8 hrs) were applied. Total nitrogen and total phosphorus removal efficiencies were 74% and 89%, respectively when high CODin was supplied to the MBRs. The comparison of microbial community structure between the sludges from the MBR performing poor biological phosphorus removal and from the MBR demonstrating enhanced phosphorus removal pointed out that microorganisms containing ubiquinone UQ-9, and menaquinone MK-7, -8(H2), -9(H4) and -10 (H4) were responsible for improvement in treatment efficiencies. The analysis of microbial community structure indicated that subclass ï§- Proteobacteria, species of the genera Rhodoccocus, members of the genus Gordonia and Microlunatus phosphovorus can be considered potential phosphate accumulating organisms in the MBR.
SEISMIC HAZARD ASSESSMENT OF KUALA LUMPUR USING PROBABILISTIC METHOD
Authors: Delfebriyadi Delfebriyadi
Published: December 2024

This paper presents the seismic hazard assessment which involved spectral hazard for 10 % probability of exceedance in 50 years or correspond to return period of approximately 475 years for bedrock of Kuala Lumpur city. The analysis was performed using the total probability theorm with 2D seismic source model. Time history data for this site was generated synthetically by modifying the existing time history data using spectral matching analysis. In this study, design response spectra were developed by applying the methods proposed by 1997 NEHRP. The final result are the spectral accelaration and the synthetic time histories on the bedrock, and the design response spectra on Kuala Lumpur ground surface for 475 years return periods.
APPLICATION OF STATISTICAL DOWNSCALING MODEL FOR LONG LEAD RAINFALL PREDICTION IN KURAU RIVER CATCHMENT OF MALAYSIA
Authors: Hassan Zulkarnain , Harun Sobri
Published: December 2024

The climate impact studies in the hydrology are often relying on the climate change information at a fine spatial resolution. However, Global Climate Models (GCMs) which is regarded as the most advanced models yet for estimating the future climate change scenarios are operated on the coarse spatial resolution and not suitable for climate impact studies. Therefore, in this study, the Statistical Downscaling Model (SDSM) was applied to downscale rainfall from the GCMs. The data from single rainfall station located in the Kurau River were used as input of the SDSM model. The study included the calibration and validation with large-scale National Centers for Environmental Prediction (NCEP) reanalysis data, and the projection of future rainfall corresponding to the GCMs-variables (HadCM3 A2). The study results shows that during the calibration and the validation stage, the SDSM model can be well acceptable in regards to its performance in the downscaling of the daily and annual rainfall. For the future period (2010- 2099), the SDSM model estimates that there were increases in the total average annual rainfall and generally, the area of rainfall station become wetter.
RISK-BASED ASSESSMENT ON MALAYSIAâ€™S OFFSHORE JACKET PLATFORM
Authors: Sambu Pott Narayanan , Mohd Akram Mohammad Kabir , Khamidi Mohd Faris
Published: December 2024

Malaysia has approximately 200 fixed offshore structures, some of which have been in operation for over 40 years, which is well beyond its design life. In order for these ageing fixed structures to continue in service or extend its operation, their current structural integrity condition needs to be identified, addressed, prioritized and appropriate mitigation measures should be implemented. The aim of the research was to modify the framework for Structural Integrity Management developed by AMOCO for carrying out risk based assessment of Malaysiaâ€™s fixed offshore platforms. This required acquiring actual fixed offshore structure data, which comprises of design, assessment and inspection records. Two important components of this framework were identified as 1) Base line Risk ranking of Malaysiaâ€™s offshore platforms and 2) Development of a Risk Based Underwater Inspection (RBUI) programme. The classification of the platforms showed that many of the structures have exceeded the design life of 30 years. The baseline risk evaluation of the 186 platforms showed that fifty five platforms were in â€œvery high riskâ€ category. A risk based underwater inspection guideline was also developed. A case study was done to illustrate how it affects the inspection planning of the offshore structures.
WAVE CHARACTERISTICS AROUND PERFORATED PILES IN A TWO ROWS ARRANGEMENT
Authors: Mohd Anuar Norzana , Jaffar Sidek Faridah
Published: December 2024

An experimental study was performed to investigate the transmission response of a two-row perforated double ring pile (DP). The tests were conducted in unidirectional waves with different wave conditions and pile porosity that varied from 0.0625 to 0.48. From the experimental results, it was found that when the pile porosity increases, less wave energy was attenuated, resulting in higher wave transmission coefficient, Kt . Furthermore, Kt was found to be decreasing when the wave steepness increases for all porosity values. Moreover, higher water depth has higher Kt especially at low relative depth range between 0.1 and 0.15 with Kt being more than 0.3 at a water depth h â‰¤ 0.27 m and Kt was more than 0.60 when h â‰¥ 0.3 m. Tests on spacing B and model width W were also investigated. Wider spacing (B â‰¥ 0.5D) resulted in lower wave attenuation, whilst wider model of more than one row generally attenuated more wave energy as expected. However the percentage of attenuation of the model system with more than two-rows tends to be ineffective, thus indicating that the test model with a width W>2D has less influence in attenuating waves. An empirical equation to predict transmission coefficient was also derived based on statistical analyses using independent wave parameters namely relative depth (h/L), wave steepness (Hi /L), relative model spacing (B/L) and model porosity (ï¥). A multiple linear regression analysis was used to model the relationship of these variables. Comparisons of transmitted wave performance by other researchers were also analyzed.
MECHANICAL PROPERTIES AND DURABILITY OF SOME SELECTED TIMBER SPECIES
Authors: Hossain M. Bellal , A.S.M. Abdul Awal A.S.M. Abdul Awal
Published: December 2024

An investigation was carried out to study physical properties, strength and durability of some timber species commercially used in Bangladesh. Seven timber species namely Teak (Tectona grandis), Sal (Shorea robusta), Sil Korai (Albizia procera), Rain Tree (Samanea saman), Jam (Syzygium spp.), Jackfruit (Artocarpus heterophylus), and Mango (Mangifera indica) were tested for density, specific gravity, compressive, tensile and bending strength following ASTM standards. Four different kinds of chemical environments consisting of normal water, sodium chloride (5%), sodium sulphate (10%) and hydrochloric acid (5%) were made and tested for durability in terms of strength loss over a period of 90 days. The test results revealed that Sal, Teak and Jam were the best species of using as compression member while Sal and Teak showed the best performance in tension. In static bending Sal, Sil Korai, Teak and Jam have been found suitable. With respect to durability acidic environment has been shown to be the most aggressive agent. Saline water was comparatively safer for all kinds of timber species. Overall, the Rain Tree showed excellent performance in all chemical environments having minimum loss of strength, and Sil Korai has been found to be the most vulnerable one to the same environments among all the timber species
A SURVEY ON THE IMPLEMENTATION OF FACILITIES MAINTENANCE MANAGEMENT SYSTEM OF BUILDING IN IRAN
Authors: Nima Amani Nima Amani , Mohamed Ali Nasly , Mohammed Abdul Hakim , Abd Samat Roslida
Published: December 2024

The degree of the implementation of building facilities maintenance management (FMM) has a major impact on its performance. As a result, the influence of facilities management on the maintenance of buildings is greater than ever before. The issue related to building maintenance is a universal one and its consideration at the facilities maintenance stage is of great importance on the future performance of the building. This research has been conducted to study the impact of maintenance-related issues on facilities maintenance management system. Building maintenance includes cleaning, inspecting, repairing, and replacing the buildingâ€™s various systems and components. Questionnaires were distributed in big cities of Iran. The findings identified the level of companiesâ€™ knowledge in facilities maintenance-related issues; the degree to which executive staff is exposed to training in facilities maintenance-related matters; the extent to which companies consult maintenance consultants; the relative importance of facilities maintenance (FM) issues to other performance factors and the level of difficulty in cleaning, inspecting, repairing, and replacing various building components. Based on the findings, the main problems related to management of facilities maintenance system of building needs serious attention from the authorities in order to improve the overall maintenance system.
ECONOMIC AND FINANCIAL ANALYSIS FOR POLYMER MODIFIED BITUMEN
Authors: Bagui Swapan Kumar , Ghosh Ambarish
Published: December 2024

Presently conventional bitumen and polymer modified bitumen are widely available in the market for road and highway construction. Reliable and robust bituminous concrete can be produced using both conventional bitumen and polymer modified bitumen. Thickness requirement of polymer modified bitumen is lesser than that of conventional bitumen but initial cost of construction of the former is comparatively higher. Moreover, maintenance and repair cost of polymer modified bitumen is also relatively lower than that of conventional mix during service period of road and highway infrastructure. The paper presents the advantage of polymer modified bitumen over conventional materials based on results of economic and financial analysis from a real case study with the provision of glare screen for road median barrier. Net present value and internal rate of return are determined using HDM 4 software. Road with polymer modified bitumen is found economically and financially most viable option.
DERIVATION OF OIL PALM SHELL-BASED ADSORBENT USING H2SO4 TREATMENT FOR REMOVAL OF ATRAZINE FROM AQUEOUS SOLUTIONS
Authors: Tan Ai Wei Ivy , Lim Lik Pueh Leonard , Rosli Nor Azalina , Tiew Huang Ling
Published: December 2024

Activated carbon is a prominent material for adsorption of atrazine, however its usage is restricted due to the high cost. Thus, alternative adsorbent derived from agricultural waste has been investigated. This study was conducted to investigate the feasibility of oil palm shell-based adsorbent to remove atrazine from aqueous solutions. Oil palm shell-based adsorbent was prepared using H2SO4 treatment. The adsorbent was characterized for the surface morphology and surface chemistry via scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. SEM micrographs confirmed that the H2SO4 treatment developed porosity on the surface of the adsorbent. The FTIR spectrum obtained for the adsorbent before and after the treatment was almost similar. Batch adsorption experiments were conducted to determine the effects of initial atrazine concentration (5 - 30 mg/L), contact time, adsorbent dosage (0.2 â€“ 2.0 g) and solution pH (pH 2 - 12) on the adsorption uptake of the adsorbent for atrazine. The adsorption uptake of atrazine increased with increasing initial concentration. The percentage of removal of atrazine increased with increasing adsorbent dosage, but it decreased as the solution pH increased. The equilibrium data were well described by the Freundlich isotherm model. Kinetic studies showed that the adsorption of atrazine on the adsorbent followed the pseudosecond-order kinetic model. Based on the experimental results, it was evident that the oil palm shell-based adsorbent derived in this work might be employed as a low cost adsorbent for removal of atrazine from aqueous solutions.
DYNAMIC ANALYSIS OF COMPLEX STRUCTURE BY EQUIVALENT METHODS: APPLICATIONS TO ISOTROPIC AND ORTHOTROPIC PLATES
Authors: Sekhri Abdelhak , Benmansour Toufik , Mebarki Abd Elyamine , Hamada Samy
Published: December 2024

This paper intends to provide an equivalent method for the evaluation of natural frequency of isotropic and orthotropic thin rectangular plates with different restraint conditions. Starting from a simple and a general approximate formula for the frequency, which is the extension of Hearmonâ€™s expressions presented for the fundamental mode; it is shown how to calculate the fundamental mode of isotropic and orthotropic rectangular plates using the proper coefficient values already available in the scientific literature. For the higher modal frequencies, a particular form of Rayleighâ€™s method is proposed, leading to a simple procedure to calculate the fundamental frequency. In fact the frequency calculation is reduced to the evaluation of the fundamental frequency of a special plate associated with the real one. An extensive finite element investigation was carried out to test the accuracy of this analytical short cut method. In addition a comparative study has shown good agreement between the frequencies responses obtained from both analytical (equivalent method) and finite element solution using ANSYS program. This method allows us to both avoid huge calculations, and produce a fast and simple approximate calculus of free vibration frequencies. This in turn is a necessary part of the preliminary design phase and the general and immediate verification of a construction project to its completion.
FATIGUE LIFE OF MALAYSIAN HOT MIX ASPHALT MIXTURES
Authors: Hainin Mohd Rosli , Abdulridha Ammar Ali , Yaacob Haryati , Haron Zaiton , Md. Yusoff Nur Izzi
Published: December 2024

Fatigue cracking is one of the major types of distress in asphalt concrete pavements. Under the action of repeated vehicle loading, the asphalt concrete deteriorates and eventually results in fatigue cracking. This study investigated the effect of temperature, aggregate gradation, nominal maximum aggregate size, and asphalt types on the fatigue life of hot mix asphalt (HMA) mixtures. Six mixtures conforming to JKR/SPJ/2008 were selected, namely asphaltic concrete with a nominal maximum aggregate size of 10 mm (AC10) and 14 mm (AC14), polymermodified asphalt concrete 10 mm (PMA10) and 14 mm (PMA14), and stone mastic asphalt 14 mm (SMA14) and 20 mm (SMA20). Specimens were prepared with the optimum asphalt content using the Marshall Mix design procedure. An indirect tensile test for the resilient modulus was performed according to ASTM D 4123. A fatigue test was also conducted to determine the performance of the mixtures. The specimens were prepared using 80/100 penetration grade asphalt for AC10 and AC14, and PG76 asphalt for PMA10, PMA14, SMA14, and SMA20. Fatigue tests with constant stress were performed using a Universal Testing Machine at 25 ËšC and 40 ËšC at a load of 1000 N. Results show that the fatigue life of asphalt mixtures was lower at 40Ëš C than at 25 ËšC. It was also observed that the mixtures with the smallest nominal maximum aggregate size had a higher fatigue life. The PMAs developed greater fatigue performance than SMAs and ACs due to the aggregate gradation and asphalt type.
A STUDY OF FATAL AND NON-FATAL ACCIDENTS IN CONSTRUCTION SECTOR
Authors: Mohammed Yakubu Danasabe , Ishak Mohammad Bakri
Published: December 2024

Occupational accident in the construction sector in 2010 alone includes 66 fatal and 54 non-fatal. The objectives of this study are; to study fatal and non-fatal accident and to determine contribution of fatal and non-fatal accident to the total number of accident. The result indicates that there is no clear positive or negative trend in the number of fatal and nonfatal accident from year 2002 â€“ 2010. Furthermore, the result of the Sensitivity Analysis shows that fatal accidents (53.53%) contribute more to accident rates than nonfatal accident (47.46%). This study provides useful information as regard to the contribution of fatal and nonfatal accident to the total number of accident and the key impact variable. Therefore, from the information provided, it is evident that an effort towards safety program is vitally needed at construction sites. Management commitment, safe working condition and safe work habits are all what are needed for effective implementation of safety program.
RESTRENGTHENING OF RCC BEAM BY BEAM JACKETING
Authors: Jamil Md. Akhter , Zisan Md. Basir , M. R. Alam M. R. Alam , Alim Hafizul
Published: December 2024

The partial damage of structural components cause failure of serviceability and safety requirement of structures and economical losses of owner. Re-strengthening of structures during its life cycle management became major issue for civil engineers. The purpose of this paper is to assess the structural performance and strength behavior for a partially damaged flexural member and also the ultimate load capacity of cracked reinforced concrete beam re-strenghtened by RCC beam jacketing. Structural components taken into consideration are flexural cracked and uncracked reinforced concrete beam. The numerical analysis is conducted by using the finite element software ANSYS to evaluate the behavior of cracked and un-cracked beam under different loading conditions. A further numerical analysis is done for the same beam after restrengthening by â€˜beam jacketingâ€™ technique. It is observed that beam jacketing technique reduces the stress at crack tip to a value less than that of uncrack beam stress . It reduces not only the stress at crack tip but also increases the load carrying capacity and stiffness of the beam.
ULTIMATE STRENGTH ASSESSMENT FOR FIXED STEEL OFFSHORE PLATFORM
Authors: Sambu Potty Narayanan , Ahmad Sohaimi Ahmad Fawwaz
Published: December 2024

Currently, more than 80% of Malaysiaâ€™s offshore platforms are aged 30-40 years which is beyond the design life of 25 years. Structural assessments are needed to gauge the platforms for the extended use. The two common methods widely used are the simplified ultimate strength analysis and static pushover analysis. Simplified ultimate strength is attained when any of member, joint, pile steel strength and pile soil bearing capacity reaches its ultimate capacity. This is the platformâ€™s ultimate strength. Static pushover analysis generally concentrates on RSR (Reserve Strength Ratio) and RRF (Reserve Resistance Factor) for the ultimate strength. This report summarizes a study of the ultimate strength of jacket platforms designed using API RP2A-WSD 21st Edition (2000) using SACS software with the module for Full Plastic Collapse Analysis. Two types of analyses have been carried out. First the ultimate strength of jacket platform with different number of legs is determined and in the second part the collapse load of platforms for different bracing configuration is studied. The non-linear pushover analysis is done by programming the software to analyze the structure with a set of incremental load until the structure collapses. The non-linear analysis module will distribute the load to alternative load paths available within the jacket framework until the structure collapse or have excessive deformation. In order to cater to uncertainties and distribution of data, several criteria of platform site location, age of service, type of platform, number of legs and other critical-related characteristics were considered. From the first phase of study, it is seen that a platform with more legs has higher ultimate strength compared to less number of legs. Hence a bigger jacket platform with eight legs is stiffer than smaller platform. The bracing configuration study shows that the X-bracing contributes highest rigidity to the whole platform by retaining the platform until the highest load compared to other configurations.