Pusat Pengajian Kejuruteraan Awam - Tesis

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3D rock slope stability assessment using anisotropic materials model
(2020-10-01)
Nagendran, Sharan Kumar
Rock anisotropy is a well-known phenomenon relating to the heterogeneity of rock mass. Nevertheless, its influence in geotechnical design, especially in rock engineering, is often ignored. Slope with certain modes of failure can be evaluated conventionally as well as numerically. For this study, the rock slope assessment was conducted numerically using 2D and 3D Limit Equilibrium Method (LEM) utilizing the Slide program by Rocscience. The fundamental roles of the discontinuities present in the study area were evaluated to study their influence on slope stability. Anisotropic material model was incorporated in the LEM analysis to investigate the presence of discontinuities. The measurement of discontinuity orientation in the rock slope by traditional scanline survey is time-consuming and challenging due to accessibility issues. Structure from motion (SfM) photogrammetry using Unmanned Aerial Vehicle (UAV) allows a quick and cost-effective way to do survey mapping for geotechnical assessment on rock slope compared to terrestrial laser scanner (TLS). Dense point cloud is exported to the CloudCompare tool for geological plane extraction. The stability of the rock slope was evaluated using the deterministic 3D and 2D Limit Equilibrium Method (LEM) using the geometry of the 3D rock slope system. In this study, the anisotropic material model was utilized to examine the Factor of Safety (FoS) results. Generalized anisotropic material model was used for incorporating the Generalized Hoek Brown criterion (rock mass), Mohr Coulomb (weak joint) and Barton Bandis criterion (weak joint). The rock mass and shear strength parameter for numerical analysis were determined via destructive and non-destructive tests such as Uniaxial Compressive Strength (UCS), Schmidt Hardness and JRC estimation using Barton comb. The discontinuities extracted are reliable and accurate as they are within 10° of the data measured manually. By using discontinuity data, the kinematic analysis shows that the rock slope has 12.80% of risk in planar sliding, 6.67% in wedge sliding and 1.93% in flexural toppling. Mean dip / dip direction obtained was used as an input for the value of the anisotropic plane where it causes a weakness in the strength of the rock slope. The results of FoS shows that rock slope without anisotropy model is stable and analysis using anisotropic material model predicts that the slope may fail. 3D slope stability analysis was able to identify the weakest spot easily rather than to assume based on the results of 2D slope stability assessment which might represent the whole rock slope. 3D rock slope stability assessment proves to be very cost-effective method for remedial work whereas in 2D stability assessment, wrong cut-sections may provide inaccurate FoS. This study presents the approach of using anisotropic material model utilizing basic rock testing and field observation data to analyse the rock slope stability.
Analysis on self-reported risky riding behaviour of motorcyclist using partial least square structural equation modelling
(2021-10-01)
Goh, Wins Cott
This study was conducted among Malaysian motorcyclists to address the high fatality rate of motorcycle traffic accidents. Research has shown that age, gender, likeness towards a risky riding behaviour (positive affect), and perception of risky riding behaviour significantly impact a rider’s judgement on the road. Thus, this study is initiated to better comprehend the behaviour of Malaysian motorcyclists. A study was conducted to obtain demographic information, risky behaviour engagement, positive affect, and risk perception among Malaysian motorcycle riders. The survey results were then analysed using the Structural Equation Modelling – Partial Least Squares approach to assess the survey's reliability and validity. Consequently, a statistical model was created based on the hypothesis model, where the relationship among each latent construct is evaluated. The statistical model in this study included age, gender, riding experience, trip distance, motorcycle type as the construct of personal characteristic. A total of four hypotheses are accepted from the initial six hypotheses. Crucial evaluation from the model reveals that the positive affect construct has the strongest positive relationship with the construct of risky behaviour (t-value = 15.517). Findings in the model also show that the personal characteristics of rider has a direct effect on risky behaviour (t-value = 2.175). In addition to these findings, the model has also revealed an indirect effect from personal characteristics towards risky behaviour through positive affect was also significant (t-value = 3.885). These results concur with most studies conducted on motorist driving behaviour. Thus, with these findings, it can be concluded that risky behaviour engagement of Malaysian motorcyclist reduction should be approached from the perspective of encouragement and empowerment instead of enforcement and deterrence.
Application of tin (IV) tetrachloride and jatropha curcas in coagulation-flocculation process for the treatment of stabilised landfill leachate
(2021-11-01)
Syed Zainal, Sharifah Farah Fariza
Leachate is one of the most common problems faced by landfilling methods that can jeopardize the life and environment due to the excessive concentrations of pollutants. It must be treated first before discharge into the environment. The coagulation-flocculation (C-F) process has been extensively used in landfill leachate treatment. However, leachate needs high strength coagulant to remove higher pollutants. The application of tetravalent metal salts coagulant in combination with a natural coagulant and the effectiveness of tetravalent metal salts in a C–F process is still inclusive. This study was performed to determine the best C-F operational conditions such as pH and coagulant/flocculant dosage, rapid mixing, slow mixing, and settling on the removal of chemical oxygen demand (COD), colour, and suspended solids (SS) in a stabilised leachate from Alor Pongsu landfill site, Kerian, Perak as a case study site. Tin (IV) Chloride (SnCl4) and Jatropha curcas (JC) seed or ‘buah jarak’ was tested as a sole coagulant and later mixed with JC reacted as a flocculant. A series of jar tests were conducted, and the C-F mix was optimised using response surface methodology (RSM) and central composite design (CCD). Floc’s size and sludge properties were also evaluated, followed by an acute toxicity test on the raw and treated effluent. Excellent removals of 99.5 %, 98.4 %, and 71.5 % for SS, colour, and COD, respectively, were obtained by using 11.1 g/L of SnCl4 as coagulant alone at pH 8. JC seed was poor as a sole coagulant with only 33.9 % and 23 % reductions in colour and COD, respectively, with no removal in SS. However, with the combination of SnCl4 as a coagulant and 0.9 g/L of JC seed as a flocculant, the SnCl4 dose was reduced to xxiv 8.5 g/L with 99.8 %, 98.5 %, and 74.3 % reductions in SS, colour, and COD, respectively. The sludge and floc characteristics tested showed that JC helped in producing larger flocs, increasing the sludge velocity, and having a higher flocculation index. The treated sample with SnCl4 as coagulant and JC as a flocculant could reduce the toxicity effects to tested Tilapia fish and is safe to be discharged at appropriate dilution concentrations. It can be concluded that JC seeds have the potential to be applied as a natural flocculant with SnCl4 as the main coagulant in the treatment of leachate. This could reduce the dose of the inorganic commercial coagulants currently in use with better sludge properties.
Assessment of non-seismically designed timber-concrete hybrid building under earthquake scenario in Malaysia using shake table test
(2022-08-01)
Richard Ng, Eng Yao
Most of the buildings in Malaysia have not considered lateral loads in the design, especially traditional houses. Therefore, they may be susceptible to damage caused by earthquake as demonstrated in the past earthquakes. In addition, no shake table test has been performed on traditional houses in Malaysia. Previous studies show that irregular buildings perform poorly when earthquake strikes. Thus, this research aims to study the seismic performance and develop the correlation of response for L-shape in plan buildings with various frequencies under different peak ground accelerations (PGAs). In this study, the model was down-scaled into 1:4 and has been built in the hybrid timber-concrete floor system. The model was tested with different types of ground motions, i.e. near field and far field with large displacement and various PGAs, namely, 0.05, 0.08, 0.12 and 0.16 g. The building frequencies within 2.70 Hz to 6.25 Hz were varied by changing the lateral force resisting system. The largest roof acceleration difference for the shorter wing section to the longer wing section of the building was 1.12 times; whereas the largest roof displacement difference for the shorter wing section to the longer wing section of the building is 1.17 times. The experimental result shows torsional effect. Numerical analysis based on interpolation of excitation for a single degree of freedom system was also performed to compare with the experimental results. The maximum roof displacement at shorter and longer wings of the building based on experimental analysis is 1.85 and 1.67 times larger than that predicted by numerical model based on single degree of freedom system, respectively. Prediction equations for the maximum responses (accelerations and displacements) based on building frequencies and PGAs for near field and far field with large xxiii displacement earthquake were proposed at the end of the study. This study helps to understand the response of the L-shape irregular hybrid timber-concrete structure. Moreover, the prediction equations developed were able to help engineers to design new buildings and to strengthen the existing buildings to withstand earthquake excitation.
Coagulation process of textile wastewater using composite coagulant - zinc oxide, acrylamide and tannin (zopat)
(2021-09-01)
Ishak, Siti Aisyah
Composite coagulant is known as the combination of two or more polymer into one compound either through structurally, chemically or functionally. The addition of chemical charged molecules can destabilize the suspended colloidal particles and settled down the flocs. The primary aim of this research was to synthesis composite coagulant ZOPAT from zinc oxide (ZnO), acrylamide (PAM) and tannin. To achieve this the different ratio was applied during blended technique for 24H. The jar test condition was experimented at various pH, dose, rapid mixing, slow mixing and sedimentation time to get the optimum coagulation process. Then, Response Surface Methodology was applied using Central Composite Design to achieve the optimum pH and ZOPAT dose. In addition, the formation of floc and sludge were studied and compare before the treatment. This research was the first to incorporate zinc oxide (ZnO), acrylamide (PAM) and tannin as ZOPAT using ratio (A) 1:1:1. The optimum condition for pH and ZOPAT dosage analysed throughRSM-CCD resulted in 93% of colour, 80% of COD, 100% of turbidity and suspended solids were obtained at the pH 9.22 and 737 mg/L ZOPAT. The performance of ZOPAT indicate better sludge settleability which resulted in sludge volume index at 74.42 mL/g, and settling velocity at 1.63 cm/min. The present of Zn, N and K contribute to electrostatic attraction with the opposite charge particles. The chemical bond form between dye-particle-dye with amide, hydroxyl, carboxyl groups in ZOPAT can remove the colour, turbidity, COD and SS.
Correlations between the spt-N value and undrained shear strength for alluvium soil
(2022-09-01)
Tan, Jia Jun
Standard Penetration Test (SPT) is one of the most popular and common in-situ dynamic soil penetration testing methods used to determine the shear strength properties of soils. There are several empirical correlations between the SPT blow count value (SPT-N) and undrained shear strength (Su) of fine-grained soils. However, no available empirical correlations are established for the alluvial soils. Only a limited number of correlations were previously developed for certain soil groups (e.g., residual soil) at specific locations, with uncertain prediction accuracy for different soil groups and ground conditions, particularly in the alluvium formation. With that, this study aimed to evaluate the applicability of SPT in estimating the Su of fine-grained alluvial soils. A total of 234 pairs of SPT-N and Su were collected from previous soil investigation works in Penang Island, Malaysia. After the data screening process, 98 pairs of SPT-N and Su were employed to derive new predictive equations using simple linear regression. New predictive equations were developed according to type, plasticity, and geological origin of the studied soil data. The simple linear regression results revealed the significance of type and geological origin of the studied soil data in influencing the correlation between SPT-N and Su. This study proposed two newly developed equations, and comparisons were made with the studied soil data and correlation equations from previous studies. This study evaluated the prediction capability of the proposed equations and previous studies using graphical analysis (scatter diagram) and statistical analysis like absolute average relative error (AARE) and standard deviation (SD). The proposed equations were found to be reliable in estimating the Su of the fine-grained soils (AARE= 0.29 to xix 0.31, SD= 0.31 to 0.36). For previous studies, the results showed a more noticeable deviations between the soil data and predicted values (AARE= 0.60 to 0.65, SD= 0.31 to 0.41), signifying that the correlation equations may have underestimated or overestimated the shear strength values. The two newly proposed equations were also compared and validated with soil data of outside Penang Island, and these equations showed good reliability. In addition, this study investigated the effect of SPT corrections on the relationship between SPT-N and Su. When the corrections were applied to the SPT-N, for the previous published correlations, the AARE and SD increased by up to 46.5% and 70.73%, respectively. This research also provided new insights into the influence of each correction factor (borehole diameter, sampling method, and SPT hammer energy ratio) as well as the performance of existing correlations. The results revealed that the SPT hammer energy ratio correction was the most significant factor in influencing the relationship between SPT-N and Su. The study’s findings on the prediction capability of the empirical shear strength correlations for the purpose of geotechnical designs were expected to benefit the construction industry.
Cost analyses for earthquake resistant reinforced concrete buildings based on the Malaysian National annex to eurocode 8
(2022-06-01)
Faisal, Farhanah
In Malaysia, the existing reinforced concrete (RC) buildings were designed by considering gravitational loads only. As such, some of this buildings experienced damages when subjected to dynamic loads from the local earthquakes. The 2015 Ranau earthquake is seen as a catalyst for Malaysian construction sector to accelerate the full implementation of seismic design in accordance with the published Malaysia National Annex (NA) to Eurocode 8 (EC 8) in 2017. However, the effect of seismic design consideration on the cost of construction materials for new buildings need to be investigated beforehand to provide information on economic implication to the stakeholders and contractors. Therefore, this study is conducted to estimate therequired material cost in term of concrete and steel reinforcement between non-seismic and seismic design. In this study, six models of 1, 3, 5, 9, 10 and 12-storey had been analysed under different soil types and designed for medium ductility class (DCM) with 0.16 g of peak ground acceleration (PGA) based on contour map in Malaysia NA 2017 as the existing RC buildings were assumed to be in Ranau, Sabah. The results showed that the percentage increase in the total cost of concrete for RC buildings with seismic design was in the range of 4% to 191% compared to the corresponding RC buildings designed without considering the seismic effects. Meanwhile, the percentage difference in the total cost of reinforcement for RC buildings between non-seismic and seismic design was in the range of 11% to 318%.
Development and evaluation of room temperature cured silicomanganese fume-based alkali activated binder
(2021-12-01)
Najamuddin, Syed Khaja
Silicomanganese (SiMn) fume is an industrial waste whose potency in the synthesis of alkaline activated mortar/concrete is yet to be explored. The major constituents of SiMn fume are oxides of silica, manganese and potassium (SiO2, MnO2 and K2O). Percentage of calcium oxide (CaO) is very low. Precursors with low CaO needs elevated curing to develop the strength. Concentration of this study was to develop room temperature cured binder despite low CaO to make it adaptive for in-situ construction by proper synthesis of available ionic elements in SiMn fume. SiMn fume based mortar cured at room temperature (23+2° C) was synthesized with sodium hydroxide (NaOH) of varying molarities (4, 8 and 12) and sodium silicate (Na2SiO3) as alkaline activators with different ratios of Na2SiO3/NaOH (2, 2.5 and 3). The effect of SiMn fume content (370, 470 and 570 kg/m3 ) and alkaline solution content (33, 43 and 53%) was also investigated. Initially, the alkali activated SiMn fume (AASiMnF) mortars were evaluated by means of flow, compressive strength and flexural strength. Based on the evaluation, the optimum mixes were selected and silica fume (SF) was incorporated at different dosages (1, 3, 5 and 7%) to further improve the properties of the binder. Further, the mortars with optimum SF content were again selected to study the mechanical and durability properties of AASiMnF concrete. The engineering mechanical and durability properties such as setting time, compressive/flexural/split tensile strength, water absorption, volume of permeable voids, apparent density, and resistance to acid and sulfate attack were ascertained. Microstructural features and mineral compositions were studied by X-Ray diffraction, scanning electron microscope, Energy dispersive X-Ray spectroscopy xxi and Fourier-transform infrared spectroscopy analyses. The findings show that the combination of Na2SiO3 and NaOH have shown better results compared to NaOH alone as activator. With optimum Na2SiO3/NaOH ratio of 2.5 and 12M NaOH, the maximum 28-day compressive strength of room temperature cured mortar was 36 MPa. The AASiMnF binder showed longer setting time than the OPC. The optimum content of precursor and activator (at NaOH concentration of 8 and 12M) were 470 kg/m3 and 43% respectively. The incorporation of SF has improved the properties of binder and the optimum amount of SF was 5%. The maximum compressive strength of mix 12SF5 AASiMnF concrete was 57.6 MPa. The fine particle size and larger surface area of SF has reduced volume of permeable voids and water absorption. There was an increase in the apparent density of the AASiMnF concrete. AASiMnF concrete had better strength retention during acid and sulphate attack compared to OPC mix. Except the mix 12SF5 in acid exposure there was no deterioration and change in the cross-section of the AASiMnF concrete cubes. Its ability to develop good strength at room temperature (23±2° C) curing makes it adaptive to real life applications and helps to reduce carbon dioxide (CO2) foot print.
Development of alkali-activated binder utilizing silico-manganese fume and blast-furnace slag
(2021-05-01)
Nasir, Muhammad
The negative impacts of proliferation of silico-manganese fume (SiMnF) of about 100-150 kg per tonnage of SiMn alloy produced and increase in the carbon footprint due to production of ordinary Portland cement (OPC) premised the need for this study. This is necessary to enhance public health, minimize the solid waste generation, reduce global warming and develop alternative cost-efficient construction materials for civil engineering infrastructures. This thesis addresses the use of alkali activated binding technology to mitigate the challenges associated with the concrete and other industries. This led to the development of novel and sustainable alkali activated mortars (AAMs) using high level of silico-manganese fume (SiMnF) and ground granulated blast furnace slag (GGBFS) as precursor materials (PMs) together with NaOHaq (NH) and Na2SiO3aq (NS) as the alkaline activators (AAs). The optimization of mixes was achieved using L16 orthogonal array based on the Taguchi method (TM). The mix parameters studied were GGBFS/PMs (0-0.5), sand/PMs (1.5-2.4), NH concentration (0-16M), NS/NH ratio (0-3.5), silica modulus (0-3.4) and AAs/PMs (0.5-0.53). The influence of curing methods, namely room-, moist-, and heat-curing (for 3-24 h between 25-95 °C) and durability performance under the exposure to acid and sulphate environments were also studied. Fresh properties and mechanical strength were evaluated, while analytical studies, such as mass stability, bond characteristics, nature of the products formed and morphology of the microstructures were undertaken using thermogravimetric (TG) analysis, FT-IR analysis, X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM) plus energy dispersive spectroscopy (EDS), respectively. The optimum mortar mix consisted of SiMnF:GGBFS, sand/PMs, Na2SiO3aq/10M-NaOHaq and AAs/PMs ratios of 70:30 wt.%, 1.5, 2.5 and 0.5 such that the SiO2/Na2O, H2O/Na2O and H2O/SiO2 ratios were 1.61, 17.33 and 10.77, respectively. This combination yielded a 3-, 7- and 28-day compressive strength of 22.5, 29.7 and 44.5 MPa, respectively at room-curing, whereas the heat-curing for 6 h at 60 °C was beneficial for attaining the highest strength within 3-days. Among the prominent compounds that defined the microstructure of the developed AAMs were stratlingite/gehlenite hydrate (C-A-S-H), nchwaningite/glaucochroite (C-Mn-S-H), and potassium feldspar (K-A-S-H) phases. Exposing the product to acid attack caused faster deterioration by decalcification and formation of gypsum with S-O bonds and formation of carbonation as a result of reactivity of lime with atmospheric CO2. Exposure to MgSO4aq caused more deterioration leading to spalling of specimens due to formation of gypsum and brucite crystals in comparison with Na2SO4aq where the stability was aided by quartz-based compound. It is envisaged that the results obtained from the novel AAMs would be beneficial in understanding the behaviour and an initiative towards practical application of the materials beside attaining economic, ecological and technical advantages.
Development of alkali-activated binder utilizing silico-manganese fume and blast-furnace slag
(2021-05-01)
Nasir, Muhammad
The negative impacts of proliferation of silico-manganese fume (SiMnF) of about 100-150 kg per tonnage of SiMn alloy produced and increase in the carbon footprint due to production of ordinary Portland cement (OPC) premised the need for this study. This is necessary to enhance public health, minimize the solid waste generation, reduce global warming and develop alternative cost-efficient construction materials for civil engineering infrastructures. This thesis addresses the use of alkali-activated binding technology to mitigate the challenges associated with the concrete and other industries. This led to the development of novel and sustainable alkali-activated mortars (AAMs) using high level of silico-manganese fume (SiMnF) and ground granulated blast furnace slag (GGBFS) as precursor materials (PMs) together with NaOHaq (NH) and Na2SiO3aq (NS) as the alkaline activators (AAs). The optimization of mixes was achieved using L16 orthogonal array based on the Taguchi method (TM). The mix parameters studied were GGBFS/PMs (0-0.5), sand/PMs (1.5-2.4), NH concentration (0-16M), NS/NH ratio (0-3.5), silica modulus (0-3.4) and AAs/PMs (0.5-0.53). The influence of curing methods, namely room-, moist-, and heat-curing (for 3-24 h between 25-95 °C) and durability performance under the exposure to acid and sulphate environments were also studied. Fresh properties and mechanical strength were evaluated, while analytical studies, such as mass stability, bond characteristics, nature of the products formed and morphology of the microstructures were undertaken using thermogravimetric (TG) analysis, FT-IR analysis, X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM) plus energy dispersive spectroscopy (EDS), respectively. The optimum mortar mix consisted of SiMnF:GGBFS, sand/PMs, Na2SiO3aq/10M-NaOHaq and AAs/PMs ratios of 70:30 wt.%, 1.5, 2.5 and 0.5 such that the SiO2/Na2O, H2O/Na2O and H2O/SiO2 ratios were 1.61, 17.33 and 10.77, respectively. This combination yielded a 3-, 7- and 28-day compressive strength of 22.5, 29.7 and 44.5 MPa, respectively at room-curing, whereas the heat-curing for 6 h at 60 °C was beneficial for attaining the highest strength within 3-days. Among the prominent compounds that defined the microstructure of the developed AAMs were stratlingite/gehlenite hydrate (C-A-S-H), nchwaningite/glaucochroite (C-Mn-S-H), and potassium feldspar (K-A-S-H) phases. Exposing the product to acid attack caused faster deterioration by decalcification and formation of gypsum with S-O bonds and formation of carbonation as a result of reactivity of lime with atmospheric CO2. Exposure to MgSO4aq caused more deterioration leading to spalling of specimens due to formation of gypsum and brucite crystals in comparison with Na2SO4aq where the stability was aided by quartz-based compound. It is envisaged that the results obtained from the novel AAMs would be beneficial in understanding the behaviour and an initiative towards practical application of the materials beside attaining economic, ecological and technical advantages.
Development of seismic vulnerability index framework for reinforced concrete buildings in Malaysia
(2021-03-01)
Kassem, Moustafa Moufid
Knowledge about the number of unusable and collapsed buildings in Malaysia due to earthquake-related causes is a crucial point when planning suitable intervention strategies from a structural aspect. This study intended to develop a framework that uses the Seismic Vulnerability Index (SVI) for assessing Reinforced Concrete (RC) buildings in Malaysia. The conceptual framework aimed to enable decision-making before an earthquake occurs by improving the statistical approach that depends on assumptions and expert judgment-based decisions concerning post-earthquake initiatives. Then, an analytical approach using non-linear dynamic analysis, and non-linear static analysis in the form of an improved SVI method is proposed to quantify and estimate the evolution of damage to 30-RC buildings with different clusters. Eight parameters were modelled and distributed into three distinct classes to estimate the RC-buildings’ vulnerability indexes. The vulnerability classes were categorized according to Low-, Moderate-, and High-Earthquake Resistant Designs (ERD) subjected to Far-Field (FF) and Near-Field (NF) seismic motions. SVI values classify buildings as being in a partial to total collapse state in the case of Low-ERD under certain intensities. However, upon implementing ERD installations, it explicitly achieved good seismic capacity in both Moderate and High-ERD by mitigating the damages of structural and non-structural elements. The validation process was achieved by matching the mean damage grade, plastic hinges that indicate damaged locations and failure mechanisms via storey drift with observations of the real damage. The reference buildings were graded based on mean damage states and were found to xxxvii have moderate damage to their structural elements and moderate to heavy damage to non-structural elements. As for depicting and analysing the overall results, the results were integrated into 3D Maps in the Geographical Information System (GIS). Results show that the surveyed buildings’ vulnerability are significant, and therefore, public awareness is paramount. In conclusion, the use of the analytical SVI damage indicator can be a guide for earthquake impact assessments in Malaysia, as it helps to manage and implement strategies to mitigate seismic-related actions before an earthquake strikes.
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.
Effect of glass on stiffness of the cable-net structure under the static and dynamic conditions
(2020-08)
Marzuki, Nur Ashikin
Structural glass facade or cable-net supported glass façade has been widely used as a modern building facade in engineering construction for a long-span structure of greater than 7 meters owing to its simple, light and transparent structures and these advantages make it dominant in airport, lobby and others. The contribution of glass to the stiffness on a cable-net structure normally neglected since the effect has small percentage under static load compared to a dynamic load. Nevertheless, glass panels prone to provide structural stiffness of a cable-net structure when the cables are damaged or pre-tension losses. This research aims to investigate the damages occurred within the components of a cable-net structure has determining the contribution of glass stiffness on the cable-net structure with and without glass panels under both static and dynamic behavior. An experimental carries three components of component failures, including cable-connector, cables and glass panels. The glass stiffness contribution on the performance of cable-net structure was determined from the deflection and natural frequencies of the cable-net with and without glass panels under static and dynamic behavior. Under different pre-stress level of cable forces (1000 N, 1500 N and 2000 N), the contribution of glass stiffness to the cable-net structure increased with increased cable forces within 7% to 24.5%. No major effect was readily seen in the deflection for each cable losses within edge cable to provide the huge impact upon the structure, similarly with the cable connector failure where the difference only found less than 5%. The major contribution from glass stiffness are more significant as the cable being totally damaged to contribute 7.2% to the cable-net structure. Nevertheless, under dynamic loading, when both direction of the cables subjected to cable losses, the natural frequency of the cable-net structure decreased with increasing pre-tension losses, but cable-net structure with glass panels have a small difference between in each losses, i.e 0.12 Hz from 30% to 60% losses and 0.18 Hz from 60% to 100% compared with the cable-net structure without glass panels where 0.33 Hz from 30% to 60% and 1.06 Hz from 60% to 100%. It showed that the glass panels has significant contribute the stiffness to the cable-net structure. Hence, it is important to consider the contribution of the glass to the stiffness of a cable-net structure where the design of the cable-net structure can be proposed by consider the glass panels during the design process.
Effect of non-uniform engineering properties of interlocking compressed earth brick (iceb) on the structural behavior of masonry wall
(2020-09-01)
Saari, Syahmi
The interlocking compressed earth brick (ICEB) is a new system that has reduced construction times and construction costs, making it an attractive replacement for conventional masonry structures. Although ICEB has already been used in construction, studies on the performance and properties of ICEB are still sparse, debatable and vary between the different types of ICEB. Therefore, this study investigates the properties of ICEB and the effects of ICEB walls with and without reinforcement under axial load with different aspect ratios, boundary conditions and loading arrangements. First, experimental investigations were conducted to determine the physical and mechanical properties of ICEB units and ICEB prisms. Then, 36 ICEB walls with different sizes and structures were tested under axial load with different boundary conditions and loading arrangements. The walls were analyzed using the finite element method in order to compare between the experimental and analytical results. From the results, it is evident that ICEB can be used in construction as its physical and mechanical properties exceed the minimum requirements of established standards. Apart from that, the shape, volume of void and manufacturing processes significantly affect the mechanical properties of ICEB. Even though of the properties of ICEB vary according to types, differences in the performance and behavior of the ICEB wall under axial load was insignificant. The stress-strain behavior of the ICEB wall under axial load was represented by a bilinear inelastic model and it was affected by the fissure closing stage at stress levels below 0.5 N/mm2. Moreover, the compressive strength of the wall increased as the aspect ratio increased. However, the boundary condition did not affect the ICEB wall’s compressive strength, lateral deflection and resistance to the buckling effect up to a slenderness ratio of 12. The failure patterns seen in the ICEB walls are vertical splitting and spalling of the brick. Inclusion of reinforcement in the ICEB wall slightly increased the compressive strength under uniform load, but the compressive strength increased significantly under a concentrated load. The experimental and analytical finite element method results of ICEB wall under axial load are mostly in good agreement.
Effect of sectionproperties and structural geometry on behavior of precast concrete closed spandrel arch bridge system with trapezoidal section
(2020-10-01)
Ong, Chong Yong
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.
Effects of jacket height and jacket reinforcement on seismic retrofitting of reinforced concrete columns using concrete jacketing
(2020-08-01)
Zaiter, Ali
Reinforced columns may need to be jacketed as a retrofit measure to withstand earthquake damages, aging of concrete, deficient design, steel deterioration and construction errors. Concrete jacketing is one of the common and simple methods of retrofitting. Motivated by the above concern, experimental tests were conducted on a one-third downscaled interior column of a four-storey building (SMK Ranau) to evaluate the effectiveness of the jacket reinforcement and jacket height on the structural capacities of the retrofitted column. The jacketed columns were tested under monotonic loading to determine their ultimate capacities and to design their corresponding cyclic test. Under monotonic and cyclic tests, columns with jacket h/4 high had a significant increase in their lateral load capacity. Similarly, specimens with h/2 jacket high doubled the lateral load capacity of the reference column. The jacket reinforcement showed a minor influence on the lateral load capacity. The jacket reinforcement reduced the damage level in the jacket due to the lateral confinement of the jacket transversal reinforcement. Consequently, the jacket reinforcement increased the stiffness irregularity, damage and concrete spalling in the column above the jacket. The unreinforced concrete jacket of h/2 high almost doubled the lateral load capacity and lateral secant stiffness of the damaged columns. As there were paucity studies on the effect of jacket height and type of jacket reinforcement (reinforced or unreinforced), the findings in this study were believed to provide new insight towards the concrete jacketing forreinforced columns.
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.
Efficient curing technique and optimum thickness of UHPFRC overlay for concrete repair
(2022-04-01)
Haroon, Aysha
UHPFRC is a new material which is superior in performance and is gaining research interest, particularly in the field of repair and restoration due to its good bonding behaviour with that of the repaired concrete. The performance of the UHPFRC is greatly enhanced by the application of elevated curing temperature and researchstudies have presented strong evidence towards this fact. The application of elevated curing techniques to UHPFRC, when it is being used as a repair overlay is not addressed yet. There is a need to understand this, since the performance of the UHPFRC repaired composite is greatly dependent on the property of UHPFRC repair overlay. Hence, this study was intended to evaluate the efficient curing technique of the composite with UHPFCR overlay. The hot water curing and steam curing were applied along with normal moist curing so as to relate their performance. The hot water curing presented better performances in compression, flexure and shear, and can be recommended for curing of UHPFRC overlays composites. Also, the thickness of the repair UHPFRC overlay is a matter of prime concern with the purpose of bringing down the additional weight and total cost implication of the repair material. Therefore, this study also included the optimisation of the UHPFRC overlay thickness required for restoration of the normal concrete. It was found that 20 mm of UHPFRC overlay was sufficient to repair and restore the original strength of the normal concrete. Also, the gain in strength of UHPFRC and the composite with the application of accelerated/ elevated temperature curing has been discussed with regard to its microstructural enhancement.
Emergency evacuation capacity assessment of critical evacuation facilities from platform to concourse area in rail transit terminal
(2021-08-01)
Shaari, Norley Nadirah
Besides the knowledge and emergency evacuation awareness of the passengers, the design and arrangement of critical evacuation facilities in public buildings such as the rail transit terminal (RTT) are very important in ensuring the success of the entire emergency evacuation plan in the building. The evacuation facilities such as passage, staircases, turnstiles or fair gates and exit door are the facilities that evacuees have to pass through before exiting the building. The overcrowded passengers due to available escape area and quantity of evacuation facilities may result with a bottleneck during the emergency evacuation process. The aim of this research is to (1) formulate a Conceptual Framework of Emergency Evacuation Capacity Assessment of Critical Evacuation Facilities from Platform to Concourse Area for Stesen Sentral Kuala Lumpur (SSKL), the largest RTT in Malaysia and (2) to determine the emergency evacuation capacity of critical evacuation facilities from selected rail station from platform to concourse area. The two rail stations in SSKL namely KTM Station and LRT Station were selected as the study area and five stages of research methodology (desk study, data gathering, data analysis, interpretation of findings and conclusion) were conducted to perform this research. Two major data were gathered and analysed to successfully achieve the objectives of this research are (1) configuration of building and evacuation facilities which include the quantity and available escape width of the facilities and (2) the pedestrian walking velocity of the passengers which obtained from theprevious literature. The pedestrian walking velocity varies with the situation or conditions, walking direction either in horizontal or vertical direction, cultural or environmental of the country and individual psychology or characteristic. By using the formulated conceptual framework and mathematical computation performed by MATLAB, the assessment has shown that the average capacity of all evacuation facilities at the two selected train stations differs from each other. The emergency evacuation capacity of the staircase is the lowest compared to passage and turnstile. By considering the bottleneck effect, the total evacuation capacity of LRT Station is about 22% lower than KTM Station. It has been known that there arevery limited research studies on the assessment of emergency evacuation capacity in Malaysia; this study is therefore beneficial in helping designers, authorities, users and service management to provide a better emergency evacuation plan in the future.

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