Civil Engineering Dimension (E-Journal)
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Structural Strengthening using Carbon Fiber Reinforced Polymer
Get PDFThis paper presents practical pointers to be considered in strengthening
concrete structure with Carbon Fiber Reinforeced Polymer (CFRP) which becomes more popular
nowadays. It is pointed out that the strengthening process consists of assessment, design, and
installation andthat should be done by people who are competent, experienced, and professional
in their field
Influence of Curing Age and Mix Composition on Compressive Strength of Volcanic Ash Blended Cement Laterized Concrete
Get PDFThis study investigates the influence of curing age and mix proportions on the compressive strength of volcanic ash (VA) blended cement laterized concrete. A total of 288 cubes of 100mm dimensions were cast and cured in water for 3, 7, 28, 56, 90 and 120 days of hydration with cement replacement by VA and sand replacement by laterite both ranging from 0 to 30% respectively while a control mix of 28-day target strength of 25N/mm2 (using British Method) was adopted. The results show that the compressive strength of the VA-blended cement laterized concrete increased with the increase in curing age but decreased as the VA and laterite (LAT) contents increased. The optimum replacement level was 20%LAT/20%VA. At this level the compressive strength increased with curing age at a decreasing rate beyond 28 days. The target compressive strength of 25N/mm2 was achieved for this mixture at 90 days of curing. VA content and curing age was noted to have significant effect (α ≤ 0.5) on the compressive strength of the VA-blended cement laterized concrete
Integrating Emotional Intelligence, Political Skill, and Transformational Leadership in Construction
Get PDFMuch research has been conducted to demonstrate the roles of emotional intelligence, political skill, and transformational leadership in the organisational context. However, there is a lack of research that investigates the relationships between the three, particularly in the construction project environment, thus this research attempts to fill this gap. It was hypothesised that emotional intelligence serves as the foundation of these relationships, whilst political skill is the mediator and transformational leadership is the output. Questionnaire survey was used to collect data from three large construction organisations in Australia where 273 valid responses were received. Data were analysed using structural equation modelling method to test the theoretical model. The finding of this research advances theoretical understanding by showing the relationships between emotional intelligence, political skill, and transformational leadership. Practically, it helps construction organisations strategise in recruiting and developing their project personnel
Rainwater Management Model Development for Agriculture in the Savu Island Semi-Arid Region
Get PDFSavu Island is a semiarid region with few rainfalls. The meager annual rainfall of about 1,000-1,500 mm that lasts for three to five months tends to cause draught. To cope with this situation, the Author tries to develop a rainwater management model located in Daieko village. This model constitutes an infrastructure that consists of check dam series which are constructed by simulating a computerized model of decision supporting system called “Rainwater Management for Agriculture Decision Support System (RMA-DSS) model” in the research location of Daieko village. Employing a simulated RMA-DSS model; the locations for check-dam series, and dug-wells can be determined, the size of potential irrigable lands can be determined based on water balance analysis of water samples taken from simulated check dams and inundated lands. Through this model the sufficiency of water supply for agricultural purposes and the land size for cultivation area can be predicted with a high degree of certainty
Application of Prefabricated Vertical Drain in Soil Improvement
Get PDFAlthough the use of Prefabricated Vertical Drain (PVD) in soil improvement is not new, this paper is interesting since it gives the full spectrum from preliminary design stage; trial embankment and pilot test to final soil improvement. The final installation of the PVD was based on the soil investigation report and the results of instrumentation monitoring. Finally, using back analysis, vertical and horizontal coefficients of consolidation and compression index can be determined, which can be applied to predict a more accurate prediction of settlement
Increase on Strengths of Hot Weather Concrete by Self-Curing of Wet Porous Aggregate
Get PDFThe compressive and tensile strengths of concrete made in hot weather condition decreased due to loss of mixing water caused by high evaporation. One method to overcome the problem is the use of saturated fly ash aggregate. The water content in fly ash aggregate can flow out to the hardened cement paste to continue the hydration process. This “self-curing” mechanism could produce more hydration around the surface of fly ash aggregate which sub¬sequently increases concrete strength. Experimental study has been conducted in temperature of 20o to 40o with humidity of 70% for dry curing, water curing, and nearly 100% for fog curing. Effect of self-curing could be justified as the strengths of concrete using fly ash aggregates is higher than concrete using fly ash aggregates covered with silane agent, and crushed stone aggregates. Even in high temperature, the self-curing could increase the strengths of concrete due to bond strength around the surface of each fly ash aggregates
Mechanical Properties of Clayey Sand Treated with Cement-Rubbershreds
Get PDFResidual soils of clayey sand composition can potentially be treated to construct a 2-layer pavement system. Using cement as the primary binder and recycled rubbershreds (<2 mm thick, 0.425 mm - 12 mm in length) as filler material, the improved ground can serve as a reliable road foundation, overlain with a surface capping layer. In order to determine the performance of this treated foundation layer, the relevant mechanical properties were examined using suitable laboratory tests, i.e. compaction, unconfined compressive strength and bender element tests. From the test results, it can be concluded that a mixture of cement and recycled rubbershreds effectively enhanced the mechanical properties of the soil. The cement dosage was kept at a minimum to bind the soil and rubbershreds for long term durability, while the rubbershreds served as a flexible filler material, without compromising the targeted strength and compressibility
A Finite Element Analysis of Bearing Resistance of Timber Loaded through a Steel Plate
Get PDFDecrease projected length of bolts due to bending deformation in timber joints compresses the steel washers onto timber member and increases lateral resistance of the joints. As this lateral strength increase primarily depend on bearing characteristics of timber beneath the steel washers, a finite element analysis was performed to predict their bearing-embedment behavior. A 3-D finite element model consisting of 8-node solid and contact pair elements was developed using ANSYS assuming an anisotropic plasticity model for timber and an elastic-perfectly plastic model for the washers. Material constants for both steel washer and timber member were obtained from previous test data. The results of the analysis were in good agreement with the experimental load-embedment curves as well as the analytical curves obtained in a previous study based on a rigid-body-spring-model. The same approach was also used to evaluate the effective bearing length (under uniform compression) of a 50 mm depth timber block partially compressed
Learning from Local Wisdom: Friction Damper in Traditional Building
Get PDFIndonesia is situated in the so called “Ring of Fire” where earthquake are very frequent. Despite of all the engineering effort, due to the March 28, 2005 strong earthquake (8.7 on Richter scale) a lot of modern buildings in Nias collapsed, while the traditional Northern Nias house (omohada) survived without any damage. Undoubtedly many other traditional buildings in other area in Indonesia have survived similar earthquake. Something in common of the traditional building are the columns which usually are not fixed on the ground, but rest on top of flat stones. In this paper some traditional building are subjected to non linear time history analysis to artificial earthquake equivalent to 500 years return period earthquake. This study shows that apparently the columns which rest on top of flat stone acts as friction damper or base isolation. The presence of sliding at the friction type support significantly reduces the internal forces in the structure
Settlement Control of Soft Ground using Cement-Ricehusk Stabilization
Get PDFCement is widely used for improvement of soft soils, but financial and environmental concerns are causing genuine concerns to all parties, leading to the quest for alternative and effective stabilizers. Ricehusk is an agricultural waste in Malaysia, commonly disposed of by open burning or dumping in landfills. Considering that the ashes derived from ricehusk are pozzolanic in nature, there is a possibility that a cement-ricehusk mixture could effectively improve soft soils with reduced cement dosage. This study examines the mixture’s effectiveness by monitoring the settlement reduction in a clay soil. Standard oedometer tests were carried out on a soft marine clay sample admixed with cement-ricehusk. Test specimens contained 0-10% cement and 0-5% of ricehusk respectively, and were left to cure for either seven or 28 days. The stabilized specimens were observed to undergo significant reduction in compressibility, verifying the potential of cement-ricehusk as an alternative soft soil stabilizer