Pusat Pengajian Kejuruteraan Awam - Tesis

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Effects Of Opening On The Behaviour Of Axially Loaded Firedclay Single Leaf Wall
(2006-05)
Bashar S. Mohammed
The area around openings in the form of doors, windows, and for mechanical and electrical services in axially loaded structural masonry panels are subjected to high stress concentration. There is a possibility of tension developing around these openings near the corners. Furthermore, the presence of these openings could affect the ultimate strength of the masonry panel.
Performance evaluation of steel slag as natural aggregates replacement in asphaltic concrete
(2008-11-01)
Teoh, Cherh Yi
Steel slag is one of the industry wastes engineered into road construction material. This study was carried out to evaluate the performance of steel slag aggregates as road construction material and its performance compared to granite aggregates. The steel slag aggregates were tested for its physical and mechanical properties. Two dense mix designs incorporating penetration grade 80/100 bitumen and one porous mix design incorporating penetration grade 60/70 bitumen were used to produce the specimens for testing. The dense mix specimens are referred to as 100% Steel Slag Dense Asphalt (SSDA) and 50% Steel Slag 50% Granite Dense Asphalt (SSGDA) while the porous mix specimens are referred to as Steel Slag Porous Asphalt (SSPA). During the first phase of the study, SSDA and SSGDA were tested for performance evaluation through resilient modulus, dynamic creep, Marshall stability and indirect tensile strength. Apart from the tests stated (except for indirect tensile strength), SSPA were also tested for abrasion loss and water permeability. In the second phase of the study, the same tests as those carried out in the first phase were carried out on aged specimens. Resistant against permanent deformation and low temperature cracking improved after aging for both dense mixes and porousmixes. Test results revealed that steel slag inhibits great potential as road construction material.
Properties Of Concrete Containing Rice Husk Ash Under Aggressive Environments Subjected To Wetting And Drying
(2012-01)
Putrajaya, Ramadhan Syah
Rice husk which is agro waste from a rice mill was burned at 700 oe for 6 hours in a gas furnace. The rice husk ash (RHA) was grounded using a laboratory ball mill with porcelain balls. The optimum RHA grinding time was determined. Eight different fineness grades of RHA were examined and it was found that the specific gravity and the fineness of the rice husk ash increase with an increase in grinding time. Even though. the morphology of the RHA changed with grinding. There appears to be an optimum grinding time of approximately 90 min (to 9.52 urn particle size), during which time the compressive strength and strength activity index increases significantly. The use of rice husk ash grounded for 90 min produced concrete with good strength and low porosity. On the other hand, the effect of ground RHA blended cement subjected to 5% sodium chloride solution (NaCI), 5% sodium sulfate solution (Na,S04), and seawater through cyclic wetting and drying was also investigated. Four RHA replacement levels were considered in the study: 10%, 20%, 30%, and 40% by weight of cement. The durability performance of the RHA blended cement exposed to aggressive environment was evaluated through compressive strength, Rapid Chloride Penetrability Test CRCPT), and Rapid Migration Test CRMT). In addition, microstructural changes that occur in specimens due to aggressive environmental effects were identified through thermal analysis, XRD techniques, and SEM. Test results showed that RHA can be satisfactorily used as a cement replacement material in order to increases the durability of concrete.
Soil Pile Set-Up Of Driven Pile In Clay
(2013-02)
Ng, Wen Kuan
Soil/ pile set-up is a phenomenon of pile capacity increase in a driven pile as time passes which is often ignored. Incorporation of set-up effect in routine designing of piles could result in saving due to smaller required section or lesser driving energy. This research was carried out to study if small cylindrical metal piles with diameters ranging from 12.0 mm to 75.5 mm that were driven in the field and cylindrical metal rods with diameters ranging from 9.4 mm to 25.6 mm that were tested in laboratory, were capable of measuring set-up parameters of actual working piles and determining factors that affect set-up in clays. The field tests have involved depths ranging from 1.0 m to 9.8 m and periodical data readings of up to 350 days while the laboratory tests have had 450 mm of horizontal penetrations and data collection for up to 28 days. In addition, the field tests have also included square reinforced concrete piles, 300 mm to 400 nun in thicknesses, and driven to a depth of9 m. Two sites have been used for the tests namely within the campuses of Universiti Sains Malaysia in Nibong Tebal, Pulau Pinang and Universiti Teknologi Mara in Permatang Pauh, Pulau Pinang.
Leakage Impact On Non Revenue Water (Nrw) In Sungai Petani (Kedah Tengah District), Kedah Darul Aman
(2014-03)
Mohamad Saad, Mohd Zaidi
Leakage is well known as the main reason of high physical loss in non-revenue water (NRW) and is divided into major and minor leakages. A leakage study was done in 10 District Meter Zones (DMZs) in Sungai Petani, Kedah. NRW data had been collected in cooperation with Syarikat Air Darul Aman (SADA). Data taken from year 2008 until2012 were used to investigate the major and minor leakages by doing visual inspection at site and analysis of the results were done. The baseline inflow and baseline average water consumption in cubic meter per day were collected from the Primayer 'data logger' and SADA billing systems to determine the real water losses. Statistical analysis were used to study the relationship between number of leakage with NRW cost saving, number of connection and length of pipe by using the Statistical Product and Service Solution (SPSS).
Influence Of Palm Oil Fuel Ash As Supplementary Binder On Properties Of Polymer Modified Concrete
(2014-03)
Zakaria, Nurhana
Malaysia being the second largest world's palm oil producer has led to the mounting up of the waste produced from this industry and has caused environmental problem. Palm Oil Fuel Ash (POFA) is an agricultural waste from palm oil mill that has been proven to have pozzolanic properties which can enhance the properties of concrete when used as supplementary cementitious material in concrete. POFA used in this research was processed by means of sieving, grinding and subjecting it to heat treatment of 500±50°C for l hour before undergoing the second grinding stage. The raw and processed POFA were characterized to confirm its pozzolanic characteristics. Previous researchers have recommended the use of POFA in concrete especially for strength enhancement. The use of SBR as polymer modifier in concrete has been introduced since long time ago. Although the addition of polymer modifier in concrete improved its durability properties, however, it did not enhance the compressive strength of the concrete significantly. The main objective of this research is to observe the effect of using POFA as partial cement replacement on the engineering and transport properties of Polymer Modified Concrete (PMC).
Effect of the slenderness ratio on masonry wall under axial compressive cyclic loading
(2014-07-01)
Wan Ibrahim, Wan Rohanina
Slenderness ratio is one of the factors affecting the capasity of masonry wall to resist compressive loading. Masonry wall structure is able to withstand compression load but having the large live to dead load ratio would impair the structure capability to withstand cycles of repeated loading and unloading condition. When the masonry structure is exposed to this combined factor, it is desirable to investigate the effect of the slenderness ratio on masonry wall subjected to cyclic compressive loading. In this study, twelve specimens of single leaf wall had been tested under monotonic and cyclic compressive loading with different height representing three different slenderness ratios. From this study the strees-strain curve of the monotonic and cyclic load test was obtained and the relationship between the compressive strenght and slenderness ratio of the masonry wall had been evaluated. It was observed that the masonry wall subjected to the cyclic compressive load behave as expected whereas the strength of the wall was decreased as the slenderness ratio increased and the cyclic loading pattern did not show significant effect. Meanwhile the stress-strain curves of cyclic test generally showed good agreement with the curves of the monotonically loaded specimens. This study also investigates the masonry wall strength subjected to compressive loading in relation to slenderness ratio effect using numerical modelling analysis, it was concluded that the analysis perfomed satisfactorily with poor accuracy and the vertically loaded wall under cyclic load test exhibited face-shell spalling and vertical cracking through the web and face shell and for the increasing the wall slenderness ratio, the wall chipping break about the middle of the wall due to buckling.
Performance Of Fire-Damaged Reinforced Concrete Rectangular Columns Retrofitted With Fiber Reinforced Polymer Composites
(2014-12)
Moghtadernejad, Nima
In this experimental study, a total of twenty-one rectangular RC columns have been prepared and tested under axial compression test in three groups: un-heated, heated, heated-and-repaired with FRP. The objectives of the study were firstly to study the effect of fire temperature at 500°C and 600°C on the compressive strength and secant axial stiffness; and secondly to study the effect of repairing with GFRP and CFRP including the number of layers on improvement in compressive strength and axial stiffness, of RC columns. The RC columns were exposed to fire with the method of steady-state test under temperatures of 500°C and 600°C. The heated RC columns were repaired with unidirectional CFRP and GFRP jackets in one and two layers for the purpose of investigating the improvement in the compressive strength and the secant axial stiffness of the rectangular RC columns. The experimental results show that the residual compressive strength of RC columns were 43.1 % and 34% of the compressive strength of un-heated RC columns after being exposed to temperatures of 500°C and 600°C, respectively.
Fuzzy logic-ordered weighted average model for effective municipal solid waste landfill site selection using comprehensive spatial environmental, physical and socio-economic criteria
(2018-01-01)
Ahmad, Siti Zubaidah
In Malaysia, the landfill method of municipal solid waste disposal is still the most popular due to its economic, easiness and technological ability. However, the process of opening new landfill requires tedious planning decision with regard to identifying the suitable sites. Even though the current landfill site selection (LSS) procedures in the National Strategic Plan for Solid Waste Management (NSPSWM) guidelines had specify the mitigation measures to be followed, the restrictions on the appropriateness of suitable sites for new landfill had not been deliberated comprehensively. The guidelines have not distinctly characterized the constraints or criteria for the site suitability problem as prescribed by the local Enviromental Impact assessment (EIA) guidelines.
Development of waste quantification models for Malaysian housing construction project case study for brick and tile wastes
(2018-07-01)
Hassan, Siti Hafizan
One of the main contributors to the waste generated in the Malaysian construction industry is housing projects. The construction waste has increased over years, creating environmental problems and profit loss to contractors. Limited data are available to date in Malaysia, especially in terms of sources, types and quantity. Predicting of the waste management via specific model has not been well established. The aim of this study are to explore the causes and contributory factors that cause waste generation in selected housing project followed by development of appropriate waste quantification models for the brick and tile waste, being the most waste materials normally disposed at housing project. Then, waste minimization framework is proposed which may be useable for similar project elsewhere. Site observation and interviews with labours and site management was conducted in determining the waste sources, waste management practices and labours productivity such as age, experience and nationality. The linear regression model was used for the model development. Construction waste in form of concrete, wood, steel, brick, tile, roof trusses, and roof tiles, were investigated individually by weighing and volume measurement methods. The research revealed that wastes generated in Malaysian construction are mainly caused by labours and management problems. The study found that each material has its own contributory factor. The productivity of the labours also related to the age, experience and nationality. The increased of productivity reduced the waste generated in the construction at Site Taman Ilmu, Seri Akasia and Seri Putera. Two prediction models have been developed BW=-2.359+1.605A dan MW=3.361+0.544A (BW= Brick Waste, MW= Tile Waste, A= Area). From the results the accuracy for of the model in predicting the amount of brick waste generated at Site Taman Ilmu is 77.3%, followed by Site Seri Akasia 74.6% and Site Seri Putera 61.6%. For the tile waste, the independent variables explain 91.3% for Site Taman Ilmu, 84.7% for Site Seri Akasia and 72% for Site Seri Putera. Based on performance of the models, the linear regression is found more suitable for the tile waste prediction. For the early estimation, the generated model can predict the amount of brick and tile waste based on the work area from the construction drawing. This will help the site management to take proper action to minimise the amount of brick and tile waste generated.
The perception of road pricing policy (rpp) in Georgetown, Penang
(2018-12-01)
Mat, Abu Bakar
Treatment of stabilised anaerobic landfill leachate by ozonation process with zirconium and tin tetrachlorides
(2020-04-01)
Zakaria, Siti Nor Farhana
Leachate is a crucial problem in sanitary landfills which threatens the environment due to hazardous pollutants. However, most of the current results are unable to comply with the discharge limit of effluent. Therefore, an advanced oxidation process (AOP) using ozone and coagulation was applied during stabilised anaerobic landfill leachate (SAL) treatment in this study since this method promises high degradation of pollutants. Stabilised anaerobic leachate containing high concentrations of colour (14,984 PtCo), COD (3852 mg/L), and NH3-N (1241 mg/L). The sample was taken from Alor Pongsu Landfill Site (APLS), Kerian Perak for a duration of 1 year. Colour, COD and NH3-N were investigated as a target parameter to see the performance of each method in removing pollutant. Whilst, 3 critical factors such as dosage, pH and reaction time were studied their influences on performance of all batch studies and RSM tests. The experiment started with a batch study of zirconium tetrachloride (ZrCl4) and tin tetrachloride (SnCl4) as coagulants in the coagulation-flocculation process. Results for both coagulants were recorded and compared. Next, the performance of ozonation (O3) in a semi-batch ozone reactor was also examined. Based on the results, O3 alone could only remove 85.4%, 50% and 15% of colour, COD and NH3-N, respectively. However, these concentrations still exceeded the standard discharge limits. To improve the results, O3 was combined with two chemicals which are ZrCl4 and SnCl4. An optimisation process was designed for both (O3/ZrCl4 and O3/SnCl4) using the response surface methodology software (RSM). O3/ZrCl4 improved reduction in colour, COD and NH3-N by 99.8%, 93.5% and 46%, respectively. Meanwhile, O3/SnCl4 removed 98.8%, 85.5% and 26% of colour, COD and NH3-N accordingly. An integrated treatment method consisting of ozonation and a jar test (as ZrCl4 and SnCl4 function as coagulants) was studied. Treatment using ozonation followed a jar test yielded good results compared to the treatment which started with a jar test and ended with ozonation. However, there was only a small improvement in the biodegradability (BOD5/COD) of the sample compared to other methods. On the other hand, the improvement of BOD5/COD ratio by O3/ZrCl4 from 0.02 (raw) up to 0.43 was significant. The kinetic constant reaction rate (k’) of O3/ZrCl4 was calculated and this resulted in a value of 0.1173 min-1 based on the pseudo first-order kinetic model. Another oxidation method involving O3 and O3/SnCl4 also fit the pseudo first-order kinetic model. It can be concluded from the research that, the combination of O3 and ZrCl4 presents an effective treatment method for remediating high concentrations of containing high concentrations of colour, COD, and NH3-N in SAL.
Optimization of flood inundation simulation using multi-resolution digital elevation model
(2020-05-01)
Kadir, Muhammad Azraie Abdul
Several studies have been made to improve the flood inundation simulation derived from coarser Digital Elevation Model (DEM) such as using modification spatial distribution of DEM and modification of the river cross section. All models focused on the DEM. Up until now, optimization studies of DEM resolution with flood inundation distribution relationship is scarce. This is one of the key components of flood phenomenon which requires high accuracy for further action in the flood risk management. Additionally, inflow value could also be used to optimize flood inundation simulation without disturbing the coarse DEM. In this study, the relationship between DEM resolution and flood inundation prediction was determined in an attempt to propose a new optimization method of flood inundation prediction. This was established by incorporating the inflow value into the relationship between DEM resolution and flood inundation. A hydraulic model of Sungai Bertam, Cameron Highland was developed at a scale of 1:25 to conduct experiments at different inflow value. This result was used to validate the 2D numerical simulation of HEC-RAS model. Then, the high resolution DEM was resampled into several coarser DEM to re-simulate the flood inundation. Both DEM and flood inundation results (Water Surface Elevation (WSE), flood extent, and flood area) were used to determine the effect of inflow parameter on the optimization of flood inundation simulation. Additionally, the optimization was also validated experimentally using the hydraulic model. Hydraulic model experiment indicated that the geometry of the channel (shape and slope) plays an important role in flood inundation and inflow of 64 l/s provided a significant flood inundation at the downstream of the river. A good agreement between hydraulic and HEC-RAS model was found except at low inflow (25 m3/s and 50 m3/s), velocity (maximum Mean Relative Absolute Error (MRAE) = 0.408) and flow travel time (R2 = 0.595). This is due to the limitation of diffusive wave algorithm, 2-dimensional model and effect of grid configuration. Relationship between DEM resolution and WSE gave the best R2 with minimum R2 = 0.9845 at the inflow of 150 m3/s. Increasing DEM resolution also increased the Mean Absolute Error (MAE) and MRAE index. Optimization using the relationship between DEM resolution and WSE together with several inflow values gives significant improvement up to 72 % of MRAE index for flood extent and 131.53 % of MRAE index for flood area. Validation using the hydraulic model experiment at an inflow of 200 m3/s indicated that the optimization improves the MRAE index of WSE by 23%. The study concluded that flood inundation simulation can be improved by modification of the inflow parameter, as well as the correlation between DEM resolution and flood inundation prediction.
Geological prediction ahead of tunnel face in limestone formation
(2020-05-01)
Zaki, Nur Farihan Mohammad
Construction tunnels are perceived as relevant development models used for road and rail transport systems, canals and utility transmissions, such as power supply, telecommunications and water. This study examines the construction of tunnels for the flood mitigation system implemented as part of the Timah Tasoh Western Flood Bypass project in Perlis. Tunnel construction works are classified as high-risk areas and are particularly challenging especially when they are constructed in limestone areas prone to failure due to unprecedented rock properties, such as cavity formation, cracks, weathering, water flow and discontinuities. To identify the geological conditions, long-, medium- and short-range geological predictions are performed ahead of the tunnel face by using horizontal seismic profiling (HSP), ground penetration radar (GPR) and advanced drilling, respectively. The actual geological conditions of karst limestones are determined via tunnel face mapping, which determines rock mass quality by using rock classification and Q-value systems. A comprehensive analysis is also performed to determine the accuracy of predictive methods that use tunnel face mapping in determining rock geological conditions. By referring to the actual geological conditions of the site, the tunnel face mapping analysis reveals that HSP, GPR and advance drilling have 15%, 30% and 88% differences in predicting geological conditions, respectively.
Properties Of Physically Stabilized Granitic Laterite Soil
(2020-05-01)
Rosli, Ros Nadiah
Laterite soils are abundantly available in the hilly areas of Peninsular Malaysia and their usefulness in the construction industry necessitates further investigation on their engineering properties. In the study of this thesis, the general aims were to provide the geotechnical properties of a range of laterite soils sourced from Bandar Baharu District, Kedah while the properties pursued had also involved the extended ones beyond the normally considered. Soil samples were subjected to compaction efforts with energies spent including to more than the modified Proctor with the specific aims of exploring the maximum strength and minimum permeability constant achievable by such effort. Three qualifying criteria were specifically considered namely the California Bearing Ratios (CBR) of 20 and 80% respectively for the subgrade and subbase strengths in road construction, and the permeability constant (k) of 10-9m/s for the final cover in landfill closure. Three laterite soil samples were sourced from Bandar Baharu District and were denoted as LS1, LS2, and LS3, each representing a different fines content with LS1 having least and LS3 having most. The soil classifications by the Unified Soil Classification System (USCS) were respectively SM, SC, and MH for the three given soils. Each soil was treated by various compaction energies ranging between 596 and 3576kJ/m3 to meet the CBR requirements and bentonite contents ranging between 1 and 5% to meet the k requirement. It was found that Maximum Dry Density (MDD) increased and Optimum Moisture Content (OMC) decreased with increasing energy spent in the compaction. With increasing bentonite content, MDD decreased and OMC increased. With increasing energy spent in the compaction, k value reduced but the 10-9m/s figure for landfill cover requirement was not achievable even with the maximum energy of 3576kJ/m3 spent for the compaction. With bentonite added, it became possible to reduce k value to the required 10-9m/s range for each soil however with varying amount of bentonite used and energy spent in the compaction. With the modified Proctor compaction applied, it was possible to have k reduced to within the 10-9m/s range with minimum bentonite use of 1% for LS3, 3% for LS2, and 5% for LS1. The Unconfined Compressive Strength (UCS) for each soil increased with increasing compaction energy applied. However, UCS reduced with increasing bentonite added to the soils. For the three soils, the soaked and unsoaked CBR increased with compaction energy spent increased from 596 to 3576 kJ/m3, however only for LS1 that CBR went beyond the 20% mark. After adding 5% bentonite to the soils, none of the resulting CBR values achieved the 20% mark; in this case the modified 2682kJ/m3 compaction energy for CBR was used in all tests. The morphology analysis indicated that with decreasing MDD and increasing OMC due to bentonite addition, the pore sizes shrank for all soils as the structure became more flocculated. Finally, the correlations between properties were analyzed, and the one with highest correlation coefficient was that which relates MDD to OMC.
Performance of steel roof cladding connection for rural houses roofing system subjected to uplift loading
(2020-05-01)
Azuan, Mohd Khairul
The study of the performance of steel roof cladding to purlin connection for rural houses under wind load becomes the focus of the present study. Post-windstorm survey conducted on damaged rural houses showed that the roof cladding was vulnerable to strong wind. However, previous studies are limited to the engineered building rather than non-engineered building. Mostly, the rural houses are non-engineered buildings and used the umbrella head nail as a fastener rather than screwed fastener. The experimental work using an in-house fabricated airbox was performed to investigate the pull through strength of the steel roof cladding. The numerical study using ANSYS Static Structural was performed to study steel roof cladding enhancement by an additional strip. The fastener reaction force was enhanced with respect to the increase in the cladding thickness between 102% and 137% for the trapezoidal profile and 48% for the corrugated profile. The use of an umbrella head nail connection also improved the pull through strength compared to the self-drilling screw by 22% and 35% for the trapezoidal and corrugated profile, respectively. Besides that, the trapezoidal profile recorded 11% higher of the fastener reaction force compared to the corrugated profile. On the contrary, a relatively small increase in terms of span length showed insignificant enhancement in the pull through strength. The comparison of global and local deformation shape for both FE models predicted a similar deformed shape with the experimental work. The presence of an additional strip with different width strongly improved the maximum deflection of the FE model. For the trapezoidal model, the presence of the 100 mm and 150 mm width of the additional strip decreased approximately between 7.5% and 9.5% of the maximum deflection. Meanwhile, for the corrugated model, the maximum deflection decreased approximately 35% up to 70% with the presence of the 100 mm and 150 mm width of the additional strip. However, the effect of additional strip thickness insignificantly affects the maximum deflection where the difference was calculated between 0.9% and 0.32% for both trapezoidal and corrugated profile, respectively.
Properties of physically stabilized granitic laterite soil
(2020-05-01)
Rosli, Ros Nadiah
Laterite soils are abundantly available in the hilly areas of Peninsular Malaysia and their usefulness in the construction industry necessitates further investigation on their engineering properties. In the study of this thesis, the general aims were to provide the geotechnical properties of a range of laterite soils sourced from Bandar Baharu District, Kedah while the properties pursued had also involved the extended ones beyond the normally considered. Soil samples were subjected to compaction efforts with energies spent including to more than the modified Proctor with the specific aims of exploring the maximum strength and minimum permeability constant achievable by such effort. Three qualifying criteria were specifically considered namely the California Bearing Ratios (CBR) of 20 and 80% respectively for the subgrade and subbase strengths in road construction, and the permeability constant (k) of 10-9m/s for the final cover in landfill closure. Three laterite soil samples were sourced from Bandar Baharu District and were denoted as LS1, LS2, and LS3, each representing a different fines content with LS1 having least and LS3 having most. The soil classifications by the Unified Soil Classification System (USCS) were respectively SM, SC, and MH for the three given soils. Each soil was treated by various compaction energies ranging between 596 and 3576kJ/m3 to meet the CBR requirements and bentonite contents ranging between 1 and 5% to meet the k requirement. It was found that Maximum Dry Density (MDD) increased and Optimum Moisture Content (OMC) decreased with increasing energy spent in the compaction. With increasing bentonite content, MDD decreased and OMC increased. With increasing energy spent in the compaction, k value reduced but the 10-9m/s figure for landfill cover requirement was not achievable even with the maximum energy of 3576kJ/m3 spent for the compaction. With bentonite added, it became possible to reduce k value to the required 10-9m/s range for each soil however with varying amount of bentonite used and energy spent in the compaction. With the modified Proctor compaction applied, it was possible to have k reduced to within the 10-9m/s range with minimum bentonite use of 1% for LS3, 3% for LS2, and 5% for LS1. The Unconfined Compressive Strength (UCS) for each soil increased with increasing compaction energy applied. However, UCS reduced with increasing bentonite added to the soils. For the three soils, the soaked and unsoaked CBR increased with compaction energy spent increased from 596 to 3576 kJ/m3, however only for LS1 that CBR went beyond the 20% mark. After adding 5% bentonite to the soils, none of the resulting CBR values achieved the 20% mark; in this case the modified 2682kJ/m3 compaction energy for CBR was used in all tests. The morphology analysis indicated that with decreasing MDD and increasing OMC due to bentonite addition, the pore sizes shrank for all soils as the structure became more flocculated. Finally, the correlations between properties were analyzed, and the one with highest correlation coefficient was that which relates MDD to OMC. .
Stormwater quality improvement by a porous pavement
(2020-05-01)
Makhtar, Salwa Mohd Zaini
Increasing quantity and decreasing quality of stormwater runoff is natural but problematic consequences of urbanization. In addressing the issue, the porous pavement usage with modular installation system has been the new alternative being experimented instead of the traditional impervious asphalt and concrete pavers. It allows for reduction in surface runoff quantity while lowering the concentration of hazardous stormwater pollutants, including the heavy metals, in the infiltrate. The effectiveness of porous pavement in eliminating dangerous pollutants depends upon the media materials used which are expected to capture most of the heavy metals. This research examined the potentials of an invented surface fill arrangement to be used in conjunction with the hexagonal modular system where the media tested consists of granular activated carbon (GAC), sand and zeolite. The three paver materials were of uniform gradations, respectively with hydraulic conductivity values of 0.052 cm/s, 0.064 cm/s and 0.068 cm/s, which can be considered as medium ranged. The batch study was carried out to determine the adsorption capacity of each medium in reducing the heavy metal impacts of lead (Pb), copper (Cu), cadmium (Cd) and zinc (Zn) in the influent. The adsorption isotherms of GAC, sand and zeolite towards Pb, Cu, Cd and Zn was found to follow the Langmuir model, the Langmuir adsorption capacities were noticed respecting the order of Pb > Cu > Cd > Zn, while the adsorption kinetics on all of the paver materials obeyed the Pseudo-Second Order model. Next, the Mixture Simplex Lattice Design was used in the column study to determine the optimized usage of the media in removing the heavy metals. The resulting optimum bed heights of 5 cm, 5 cm and 0 cm respectively for the GAC, sand and zeolite, corroborated with the outcome of employing the optimization function, thus validating the reliability of the given arrangement. The column study also gave percentage removals of 99 %, 88 %, 98 % 84 % for the Pb, Cu, Cd and Zn respectively. The concern for loss of efficiency due to clogging was addressed by tests carried out on a hexagonal modular unit with 5 cm thick GAC positioned at the top, followed by 5 cm thick sand at the bottom. Generally, the clogging agent was found trapped only on the mesh because of the sizes of some of the material being larger than the size of mesh opening, while the voids of the media material were found to be not of a major effect in this respect. With the GAC and sand layers combined, the hydraulic conductivity was determined to be 0.097 cm/s and this k value can be considered low for the purpose. Modelling using CFD ANSYS FLUENT software and visualizing the changes in the hexagonal module filled with GAC and sand of 5 cm thickness each resulted in a flow velocity of 3.5 x 10-5 m/s while a physical experiment on the fixed filter bed media consisting of the two materials gave an unsaturated velocity of 3.08 x 10-5 m/s. The 12 % difference between the experimental and simulated velocities was considered acceptable. The results showed that GAC and sand can be used as the media for the modular paver system that treats stormwater for heavy metals contamination while serving as a practical porous pavement alternative.
Stormwater quality improvement by a porous pavement
(2020-05-01)
Makhtar, Salwa Mohd Zaini
Increasing quantity and decreasing quality of stormwater runoff is natural but problematic consequences of urbanization. In addressing the issue, the porous pavement usage with modular installation system has been the new alternative being experimented instead of the traditional impervious asphalt and concrete pavers. It allows for reduction in surface runoff quantity while lowering the concentration of hazardous stormwater pollutants, including the heavy metals, in the infiltrate. The effectiveness of porous pavement in eliminating dangerous pollutants depends upon the media materials used which are expected to capture most of the heavy metals. This research examined the potentials of an invented surface fill arrangement to be used in conjunction with the hexagonal modular system where the media tested consists of granular activated carbon (GAC), sand and zeolite. The three paver materials were of uniform gradations, respectively with hydraulic conductivity values of 0.052 cm/s, 0.064 cm/s and 0.068 cm/s, which can be considered as medium ranged. The batch study was carried out to determine the adsorption capacity of each medium in reducing the heavy metal impacts of lead (Pb), copper (Cu), cadmium (Cd) and zinc (Zn) in the influent. The adsorption isotherms of GAC, sand and zeolite towards Pb, Cu, Cd and Zn was found to follow the Langmuir model, the Langmuir adsorption capacities were noticed respecting the order of Pb > Cu > Cd > Zn, while the adsorption kinetics on all of the paver materials obeyed the Pseudo-Second Order model. Next, the Mixture Simplex Lattice Design was used in the column study to determine the optimized usage of the media in removing the heavy metals. The resulting optimum bed heights of 5 cm, 5 cm and 0 cm respectively for the GAC, sand and zeolite, corroborated with the outcome of employing the optimization function, thus validating the reliability of the given arrangement. The column study also gave percentage removals of 99 %, 88 %, 98 % 84 % for the Pb, Cu, Cd and Zn respectively. The concern for loss of efficiency due to clogging was addressed by tests carried out on a hexagonal modular unit with 5 cm thick GAC positioned at the top, followed by 5 cm thick sand at the bottom. Generally, the clogging agent was found trapped only on the mesh because of the sizes of some of the material being larger than the size of mesh opening, while the voids of the media material were found to be not of a major effect in this respect. With the GAC and sand layers combined, the hydraulic conductivity was determined to be 0.097 cm/s and this k value can be considered low for the purpose. Modelling using CFD ANSYS FLUENT software and visualizing the changes in the hexagonal module filled with GAC and sand of 5 cm thickness each resulted in a flow velocity of 3.5 x 10-5 m/s while a physical experiment on the fixed filter bed media consisting of the two materials gave an unsaturated velocity of 3.08 x 10-5 m/s. The 12 % difference between the experimental and simulated velocities was considered acceptable. The results showed that GAC and sand can be used as the media for the modular paver system that treats stormwater for heavy metals contamination while serving as a practical porous pavement alternative.
Influence of repeated ground motion to in-plane rotation of asymmetric reinforced concrete building
(2020-06-01)
Rashidi, Azida Hj.
The seismic response of buildings due to ground motions may considerably be affected by torsion. Studies on the inelastic torsional behaviour of a torsionally restrained asymmetric building using simplified models are on going until present. However, results from a simplified one storey eccentric model are very important because they are used for the torsional behaviour assessments and pertinent code provisions for design. These results obtained using the tradionally strength-independent stiffness wall models and considering only single earthquake loadings are debateable. Repeated earthquake load condition has never been considered. Therefore this study uses a simplified, 3-dimensional one storey strength-stiffness dependant shear wall in a parametric study on the behaviour of inelastic torsion of a asymmetric building due to repeated earthquakes. Five parameters namely centres of strength (CR) and centre of stiffness (CS), lateral uncoupled period (Ti), behaviour factors (q), and slopes (r) based on elastic and inelastic conditions due to single and repeated near fault ground motion (NFGM) and far fault ground motions (FFGM) are investigated. The slab rotation results are analyzed based on two coefficient models where ‘CR’ and ‘CS’ are the variant parameters. It is concluded that the ‘CR’, ‘Ti’ and ‘q’ have significant influence to in-plan rotation while the ‘CS’ and ‘r’ did not contribute to in-plan rotation. The higher lateral uncoupled period (Ti = 1.5s) produces greater floor rotation than the lower lateral uncoupled period (Ti = 0.3s), irrespective of single or repeated NFGM or FFGM. Generally, the floor rotation is elastic in nature except when CR is close to the centre of mass of the structure. The repeated NFGM causes the building to rotate to a twice larger rotation compared to that due to repeated FFGM. Results from regression analysis show that the in-plane rotation responds exponentially due to NFGM and linearly proportional when the FFGM is applied.

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