Accuracy improvement in area-based matching for structural displacement measurements

Measuring and monitoring of structure deformations such as beams have an essential role in civil structural analysis. Measurements obtained pertaining to their displacements, among others, provide the information needed for the studies on material behaviours and structural designs. These measurements can also provide important indicators regarding to their failures. Under controlled laboratory conditions, these displacements can be determined using, for instance, high precision Linear Voltage Differential Transducers (LVDT). The high precision capabilities of these sensors make them suitable for structural deflection experiments. However, these LVDT sensors face a number of major drawbacks, such as, the sensors may be subjected to movement or damaged during the experiment, and the points measured are at pre-determined locations. In other words, displacements can only be measured at points where the LVDTs sensors are fixed. In addition, when large numbers of points of displacement are required or desired, the use of these sensors becomes prohibitively expensive and laborious. Whilst various researchers have used digital close range photogrammetry and the area-based matching approach in determining movements but work on the use of more than two images and surface models has not been reported. Therefore, this study proposes a revised method of precisely determining the displacements of structures using a multi-image area-based matching approach that uses surface models, i.e. a non-contact method. Experiments on beams under loading were performed under laboratory conditions. A series of multiple digital images were captured simultaneously using three digital single-lens reflex cameras throughout the experiments. The beam’s vertical displacements obtained from the proposed method were then validated by comparing against those obtained from the LVDTs. The results indicate that the mean differences between the displacement obtained from the proposed method and LVDTs are less than 0.5mm.The ttest conducted with a confidence level of 5% revealed that the differences between the two sets of results are not significant. It can be concluded that the use of multi-image area-based image matching using surface models is capable of measuring displacements and be used as an additional approach that complements the traditional methods in beam displacement measurements

Soil water characteristic curves of compacted kaolin for various initial moisture content

The soil water characteristic curve (SWCC), also known as soil water retention curve (SWRC), describes the relationship between water content and soil suction in unsaturated soils. The importance of SWCC can be seen, as the relationship affects geotechnical properties such as shear strength, volume change, permeability and deformability of unsaturated soils. This paper presented a preliminary study on the effect of initial water content and the density on SWCC on unsaturated compacted kaolin. Filter paper technique was used for suction measurement on the unsaturated compacted kaolin soil. Filter paper was used to determine total suction and matric suction through contact and noncontact technique. The calibration curve was used to relate with the gravimetric water content obtained in filter paper with corresponding suction. A comparison on SWCC established through filter paper was also compared with that of the axis translation technique (pressure plate extractor). The study found that the initial water content and the density respectively, have great influence on the SWCC of compacted kaolin. However, the combined effect could be seen significantly at lower suction

Implementation of project based learning for civil engineering students at Universiti Teknologi Malaysia

Implementation of Project Based Learning (PtBL) in Universiti Teknologi Malaysia (UTM) as part of Outcome Based Education (OBE) framework have faced various challenges (i.e revamp on the undergraduate co-curricullum, required high commitments from academicians & faculty and facilities to cater PtBL activities). This paper discusses the effectiveness of PtBL teaching method in an effort to develop the students’ soft skills in tandem with the technical or professional competencies; and problems, challenges and potential improvement in the course. The Survey Camp course which is offered at year one of a four years civil engineering degree programme in the Faculty of Civil Engineering (FKA), UTM was chosen for this study. It is a ten days fieldwork in which the students will carry out an engineering survey project from field to finish in groups of five to six students supervised by the academic staff. Assessment of the technical aspects was based on the students ability to meet the minimum engineering surveying’s standard whereas the assesment of soft skills was conducted during various sessions of the survey projects. Survey questionaires were given at the beginning and the end of the course as part of evaluation of the course effectiveness. The research has found that the technical aspects were achievable though with lesser degree for the engineering design. However, on the soft skills, students demonstrated an overall improvement of competency but it was difficult to determine the levels for the average students while the best and poor performers were easily observed

Investigating the feasibility of photogrammetric area-based image matching technique in the measurement of three-dimensional deflections of structures

The study of beam deflections and deformations is one of the many important areas in civil engineering. Designs need to be checked for deflections. The physical behaviour of a structural member subjected to loading provide useful information to structural engineers in deriving optimum designs. Present laboratory practice uses transducers in determining the deflections of beams. These transducers are fitted such that they are physically in contact with the beams. As such, much time is spent in the preparation of the equipment and peripherals for a particular test. Furthermore, deflections can only be measured at points where transducers are fixed and in many cases would be limited. Deflections at any other points, if desired, would be obtained by calculations. This study presents the use of close range digital photogrammetry to obtain a three-dimensional deflections of a concrete beam. Since, photogrammetry has always had the advantage of being able to provide measurements on a large number of points on the object of interest, the representation of the deflections would be enhanced. Image correspondence is achieved by using an area-based image matching which makes use of simple surface models. Laboratory tests involving load test on concrete beams were performed. Images of the beam under various load were captured using off-the-shelf digital cameras that are relatively fixed and calibrated. Whilst the image matching process employs a revised area-based matching algorithm, the image coordinate refinements and the three-dimensional model of the beam surface was acquired through elementary photogrammetric operations. Validation of the results was done by means of comparing the photogrammetric output against those obtained from the transducers. Initial results show that the differences between the photogrammetric and conventional approaches are not statistically significant. This indicates that the use of close-range digital photogrammetry in producing the deflections is a viable additional approach in determining the physical deformities of concrete structures

Innovative design of survey camp course for civil engineering program

This paper seeks to present the innovative design of the Survey Camp course for the civil engineering program at the Faculty of Civil Engineering, Universiti Teknologi Malaysia. The Survey Camp is designed as a ten day on-campus training which consists of surveying activities such as levelling, traversing and detailing. It also introduces the usage of the latest surveying tools and technologies used in typical civil engineering projects. This course allows the first year students to experience practicing engineers’ working environment in relation to surveying activities. The learning environment of the Survey Camp was converted from the traditional learning approach to student-centered learning via project-based learning since 2012 with several improvements and modifications. Furthermore, the implementation of Project Based Learning as the teaching and learning approach enhances the students’ knowledge and soft skills. Problem solving skills pertaining to civil engineering tasks and the development of soft skills such as team-working, leadership and communication skills are addressed. Assessments and feedbacks from the academic start and students were used as tools to evaluate the outcomes of the course. Recently, this course has produced a module and online assessment tools. This module and assessment tools have also been implemented at other universities, namely, UTHM (assessment tools since 2015), UMP (module, 2012 and assessment tools since 2016) and currently at UNIMAS (assessment tools). The implementation of the project based learning as a learning environment in conducting the Survey Camp course has successfully shown that the students’ attainment in developing the selected engineering professional and soft skills is enhanced

The application of convergent multi-image correlation in determining displacements in beams

Present structural and materials laboratory practice uses transducers (linear variable differential transducers- LVDTs or dial gauges) in determining the displacement of beams. As such displacements can only be measured at points where transducers are fixed and in many cases would be limited. Displacements at any other points, if desired, would be obtained by calculations. This study highlighted the use of photogrammetric multiple images matching technique to measure the vertical displacements. Laboratory experiments involving load test on concrete structures were performed. Validation of the results was done by means of comparing the photogrammetric output against those obtained from the LVDTs. Statistics have shown that the differences in displacements between the two methods are not significant

Hydrological and hydraulic study of water management system study for PT Bhumireksa Nusasejati, Sumatera, Indonesia

The hydrology and water management study in Bhumireksa Nusasejati Palm Oil Plantation was commissioned by the Kumpulan Guthrie Bhd. The objective of this study is to evaluate the hydrologic and hydraulic characteristics of the project area in relation to water navigation system of the existing canal. This study involved mainly field and hydrographic survey and investigation that include field data compilation and interpretation and hydraulic modeling exercise

A review of laboratory and numerical simulations of hydrocarbons migration in subsurface environments

The leaking from underground storage and surface spills of various hydrocarbon sources has caused the hazardous subsurface contamination. The toxic compounds of chemicals have made field study infeasible and it has been replaced by laboratory and numerical simulations. This study introduces the methodology for two-dimensional non-aqueous phase liquid experiments with the application of light reflection and light transmission methods associated with image analysis methods. In addition, this study emphasizes the experiments with numerical simulations in which data acquisition is essential for verification and validation of numerical models. The numerical efforts are supported by basic formulation, with existing codes and its application for light hydrocarbon migration simulation. Overall, this study discussed the laboratory works and numerical simulations using current visualization techniques and makes suggestions for future research

Framework of survey camp course in civil engineering program using project based learning

This paper seeks to present the framework of teaching and learning Survey Camp course using project based learning in enhancing engineering professional skills among civil engineering students. This study was conducted at School of Civil Engineering, Faculty of Engineering, Universiti Teknologi Malaysia. The Survey Camp is designed as a package of ten days which consists of surveying activities such as levelling, traversing and detailing, and also introduces the usage of latest technologies of surveying tools in civil engineering projects. Project Based Learning is implemented as teaching and learning approach to enhance students’ content knowledge and professional skills development. Online assessments and feedback from students are used as tools to evaluate the outcome of the course. It was found that the learning environment has positively enhanced students’ professional skills as needed for engineer of 2020. The impact on teaching and learning will be benefited to student, educator, educational Institution and employee/Industry. Furthermore, it will produce high quality of graduates with the ability to integrate knowledge, skills and attitudes associated with the requirement in preparation as a future engineer. For commercialization prospect, this framework could be packaged and offered to other institutions through licensing, offer courses or workshop on the designing and conducting the survey camp and being as a facilitato