Civil Engineering Dimension (E-Journal)
Not a member yet
443 research outputs found
Sort by
The Importance of Hydraulic Structures for Society: Quay Walls and Dikes in the Netherlands
Get PDFSince mankind exists, men have undertaken engineering activities to make their life more pleasant and secure. However this has not been an easy task, especially in the past. The knowledge of mathematics and physics to describe engineering problems became available only since 1400-1500. Nevertheless, great achievements have been made by man before that time, e.g. the pyramids in Egypt, the first sluice in China, the Borobudur temple in Indonesia, and the design and building activities of the Inca’s in South America. To illustrate this development, also the world economy, world ecology will be shortly mentioned. The structures that are briefly discussed in this paper are: soil and concrete dams for generating electricity, reservoirs for irrigation and drinking water, dikes, sluices, inland and sea, tunnels, and quay walls. This paper presents an overview of hydraulic structures in general with the emphasis on quay walls and dikes in the Netherlands. Examples of these structures will be discussed illustrating present state of the art and also with a view to the future. Conclusions and recommendations are given to enhance the knowledge of hydraulic structures
Strategies for Overcoming Barriers to Improving Safety in Small Construction Organisations
Get PDFThe majority of organisations in the construction industry are small organisations, how ever their safety performance is still far behind their larger counterparts. Therefore, it is important to focus on improving safety performance of small organisations so that the overall industry performance may be improved. Using a questionnaire survey, this research collected data from construction organisations based in New South Wales, Australia. Data analysis results have identified key barriers faced by small organisations when implementing safety. These barriers include the use of lowest bid price to evaluate tender submissions, lack of safety commitment from construction clients, and fierce competition. The analysis results have also revealed potential strategies for overcoming the barriers, such as including safety as an indicator in tender evaluation, more effective safety regulation enforcement by inspection and linking safety performance with insurance premium and licencing system, and subsidising safety training for small organisations. Improving safety performance in this sector cannot be done in isolation. The government, clients, and large organisations have important roles to play to change the norms and culture in the industry so that small organisations are supported in their effort to improve their safety performance
Self-healing of Micro-cracks in Engineered Cementitious Composites
Get PDFThe performance of an Engineered Cementitious Composite (ECC) to self-heal micro-cracks under a controlled laboratory environment is presented. Ten dog-bone shaped samples were prepared; five of them were preloaded to known strains and then left to heal in water in a temperature-controlled laboratory. Ultrasonic pulse velocity (UPV) measurements were undertaken to monitor the crack-healing process. It was found that all samples exhibited recoveries in UPV and were able to recover to between 96.6% and 98% of their pre-test UPV values over a period of four weeks. An accelerated rate of healing was observed in the initial two-day period immediately following the preloading test
Simple Mechanical Beneficiation Method of Coarse Fly Ash with High LOI for Making HVFA Mortar
Get PDFThis study focusses on the effect of milling of fly ash obtained from four different sources on the properties of high volume fly ash (HVFA) mortar. Two fly ash samples with low loss-on-ignition (LOI) were taken from a coal-fired power plant, while the other two with high LOIs were obtained from a textile factory and from a paper mill, respectively. Milling was performed using a rod mill at a certain period of time. The workability of HVFA mortar with constant water to cementitious ratio was controlled by adjusting the superplasticizer content. The results show that the specific gravity of fly ash increases after milling. Utilizing milled fly ash ends up with significant strength increase of HVFA mortar, especially those utilizing high LOI fly ash. This shows that milling is an excellent fly ash beneficiation technique, especially on the one with high LOI value
Structural Behaviour and Design of Geopolymer Concrete Members
Get PDFThe worldwide production of concrete is on the increase in order to meet the increasing rate of construction. Since cement production contributes to the greenhouse gas emission, it is vital to develop alternative low-emission binders to reduce the carbon footprint of concrete. Fly ash based geopolymer is an alternative binder that has potential to reduce the CO2 emission of concrete production. It has been shown in different studies that the mechanical properties of geopolymer concrete are comparable to those of ordinary Portland cement (OPC) concrete. This paper describes the behaviour and design aspects of geopolymer concrete structural members. The design aspects presented in this paper are bond of reinforcing steel in pull-out and spliced bars in beams, beams in shear and flexure, and columns in uniaxial and biaxial bending. It is shown that the current provisions for OPC concrete can be conservatively used for design of reinforced geopolymer concrete members
The Influence of Seismic Parameters on Site Response
Get PDFGeotechnical earthquake engineers have been trying to determine the most appropriate solution techniques for ground response analysis under earthquake loadings. This paper presents the importance of the adequate soil behavior model to simulate earthquake site response analysis. The influence of nonlinearity and linearity of soils on the site response is also investigated. Many methods have been proposed for the analysis of one-dimensional ground response such as nonlinear methods and equivalent linear with reduced modulus. Using 13 well known earthquake records and geotechnical information of sand in the Qeshm Island (Iran) and classification of earthquakes based on seismic parameters, the influence of each parameter on the Response spectra and Fourier Spectrum of surface of ground becomes evident. Analysis was done using two softwares; EERA (equivalent linear analysis) and NERA (nonlinear analysis) and compared. Finally, output of the software is compared with the reference result on site
Application of Spatial and Network Analysis to Evaluate Shelter Plan for Tsunami Evacuation
Get PDFThis study proposes a method for evaluating shelter plan for emergency evacuation prior to a tsunami based on service area analysis. The evacuation service areas are generated using both spatial and network analysis based on Geographic Information System (GIS). A case study in Pacitan city, East Java Province, Indonesia which is located in the South coastal area of Java Island, is picked as study area. The field has a possibility of suffering tsunami disaster because of the movement of Indo-Australian plate and Eurasian plate. The simulation result shows that the current evacuation shelters arranged by local government are not easy to access if tsunami occurs. About 50% of the residents do not have enough time to evacuate to the shelters because many shelters are located far from residential area. Utilizing public buildings around residential area for temporary shelters proposed in this study, about 96% residents in inundation area have sufficient time to evacuate to the shelters
The Role of Systems Thinking in Systems Engineering, Design and Management
Get PDFSystems thinking is a widely recognized and subscribed-to concept. Many benefits are ascribed to systems thinking and its result - the holistic solution. Yet, there is a wide range of opinion as to what systems thinking really is, and how its benefits can be realized in engineering practice. In fact, the concept of what constitutes a ‘system’ is wide and variable. The purpose of the paper is to draw together diverse perspectives of systems thinking useful in engineering, and to present a set of core concepts that are useful in the successful design and operation of engineered systems. These concepts will be illustrated with examples drawn from the author’s experience in teaching and research on engineered systems
Prediction of Missing Streamflow Data using Principle of Information Entropy
Get PDFIncomplete (missing) of streamflow data often occurs. This can be caused by a not continous data recording or poor storage. In this study, missing consecutive streamflow data are predicted using the principle of information entropy. Predictions are performed using the complete monthly streamflow information from the nearby river. Data on average monthly streamflow used as a simulation sample are taken from observation stations Katulampa, Batubeulah, and Genteng, which are the Ciliwung Cisadane river areas upstream. The simulated prediction of missing streamflow data in 2002 and 2003 at Katulampa Station are based on information from Genteng Station, and Batubeulah Station. The mean absolute error (MAE) average obtained was 0,20 and 0,21 in 2002 and the MAE average in 2003 was 0,12 and 0,16. Based on the value of the error and pattern of filled gaps, this method has the potential to be developed further
Empirical Evaluation of Construction Material Waste Generated on Sites in Nigeria
Get PDFThe study investigates the level of construction material waste generated on building sites in South-South, Nigeria. The objective is to empirically establish the level of waste generated on building sites and compare such with the allowable value in estimates. Data were collected from 30 on-going public building projects for six months. The level of material waste was calculated in percentages while one way ANOVA was employed to compare the waste values among the States in the zone. The significant difference between actual and allowable values of waste was tested using paired t-test. The level of material waste was found to be 11.69, 12.10, 10.45, 14.54, and 12.07 for concrete blocks, steel reinforcement, timber, and tiles respectively. It was concluded that these values are significantly different, with p-values < 0.05, from the allowable waste. The study recommends that the values of waste derived by this study be adopted in estimate