• Smart Structures and Systems
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• v.12 no.3_4
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• pp.251-269
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• 2013

Measurement of deflections of certain bridges is usually hampered by corruption of the GPS signal by multipath associated with passing vehicles, resulting to unrealistically large apparent displacements. Field data from the Gorgopotamos train bridge in Greece and systematic experiments revealed that such bias is due to superimposition of two major effects, (i) changes in the geometry of satellites because of partial masking of certain satellites by the passing vehicles (this effect can be faced with solutions excluding satellites that get temporarily blocked by passing vehicles) and (ii) dynamic multipath caused from reflection of satellite signals on the passing trains, a high frequency multipath effect, different from the static multipath. Dynamic multipath seems to have rather irregular amplitude, depending on the geometry of measured satellites, but a typical pattern, mainly consisting of a baseline offset, wide base peaks correlating with the sequence of main reflective surfaces of the vehicles passing next to the antenna. In cases of limited corruption of GPS signal by dynamic multipath, corresponding to scale distortion of the short-period component of the GPS waveforms, we propose an algorithm which permits to reconstruct the waveform of bridge deflections using a weak fusion of GPS and RTS data, based on the complementary characteristics of the two instruments. By application of the proposed algorithm we managed to extract semi-static and dynamic displacements and oscillation frequencies of a historical railway bridge under train loading by using noisy GPS and RTS recordings. The combination of GPS and RTS is possible because these two sensors can be fully collocated and have complementary characteristics, with RTS and GPS focusing on the long- and short-period characteristics of the displacement, respectively.

• Geomechanics and Engineering
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• v.18 no.2
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• pp.141-151
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• 2019

In this paper, it is aimed to present a detail investigation about the comparison of static and dynamic behavior of historical masonry arch bridges considering different arch curvature. $G{\ddot{o}}derni$ historical masonry two-span arch bridge which is located in Kulp town, Diyarbakir, Turkey is selected as a numerical application. The bridge takes part in bowless bridge group and built in large measures than the others. The restoration projects were approved and rehabilitation studies have still continued. Finite element model of the bridge is constituted with special software to determine the static and dynamic behavior. To demonstrate the arch curvature effect, the finite element model are reconstructed considering different arch curvature between 2.86 m-3.76 m for first arch and 2.64 m-3.54 m for second arch with the increment of 0.10 m, respectively. Dead and live vehicle loads are taken into account during static analyses. 1999 Kocaeli earthquake ground motion record is considered for time history analyses. The maximum displacements, principal stresses and elastic strains are compared with each other using contour diagrams. It is seen that the arch curvature has more influence on the structural response of historical masonry arch bridges. At the end of the study, it is seen that with the increasing of the arch heights, the maximum displacements, minimum principal stresses and minimum elastic strains have a decreasing trend in all analyses, in addition maximum principal stresses and maximum elastic strains have unchanging trend up to optimum geometry.

• Korean Journal of Construction Engineering and Management
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• v.13 no.2
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• pp.11-24
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• 2012

Recently, BIM (Building Information Modeling) technique is being considered as a critical delivery condition for the public projects according to the increase of best practices by practical application of BIM. However, since existing BIM studies are focused on the design and construction phases, those results are not considering the life cycle of a construction project. Therefore, this study suggests an integrated BIM operation process that enables an application of BIM for each phase of a construction project from planning to maintenance phases and develops an integrated BIM system based on the suggested methodologies. This study developed basic BIM functions and its application process by analyzing information systems in each project phase for a bridge construction project. Besides, this study performed case study and survey analysis for construction managers to verify a practical applicability of the developed system. Therefore, it is expected that the integrated BIM system is going to be utilized as a 3D-based integrated information management system considering life cycle of construction projects.

• Korean Journal of Construction Engineering and Management
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• v.14 no.3
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• pp.42-52
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• 2013

The aim of this study is to present a prediction model of construction cost for a bridge that has a high reliability using historical data from the planning phase based on a CBR (Case-Based Reasoning) method in order to overcome limitations of existing construction cost prediction methods, which is linearly estimated. To do this, a reasoning model of bridge construction cost by a spreadsheet template was suggested using complexly both CBR and GA (Genetic Algorithm). Besides, this study performed a case study to verify the suggested cost reasoning model for bridge construction projects. Measuring efficiency for a result of the case study was 8.69% on average. Since accuracy of the suggested prediction cost is relatively high compared to the other analysis methods for a prediction of construction cost, reliability of the suggested model was secured. In the case that information for detailed specifications of each bridge type in an initial design phase is difficult to be collected, the suggested model is able to predict the bridge construction cost within the minimized measuring efficiency with only the representative specifications for bridges as an improved correction method. Therefore, it is expected that the model will be used to estimate a reasonable construction cost for a bridge project.

• International Journal of Concrete Structures and Materials
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• v.10 no.sup3
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• pp.1-17
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• 2016

Recently, advanced transit systems are being constructed to reduce traffic congestions in metropolitan areas. For these projects, curved bridges with various curvatures are required. Many curved bridges in the past were constructed using aesthetically unpleasant straight beams with curved slabs or expensive curved steel box girders with curved slabs. Therefore, many recent studies have been performed to develop less expensive and very safe precast prestressed concrete (PSC) curved girder. One method of reducing the construction cost of a PSC curved girder is to use a reusable formwork that can easily be adjusted to change the curvature and length of a girder. A reusable and curvature/dimension adjustable formwork called Multi-tasking formwork is developed for constructing efficient precast PSC curved girders. With the Multi-tasking formwork, two 40 m precast PSC box girders with different curvatures were constructed to build a two-girder curved bridge for a static flexural test to evaluate its safety and serviceability performance. The static flexural test results showed that the initial cracking load was 1400 kN, exceeding the design cracking load of 450 kN. Also, the code allowed deflection of 50 mm occurred at a load of 1800 kN, verifying the safety and serviceability of the precast PSC curved bridge constructed using the multi-tasking formwork.

• Journal of the Korea Society of Computer and Information
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• v.26 no.8
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• pp.139-147
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• 2021

In this study, we proposed the possibility of reliability analysis of risk index by using Monte Carlo simulation as basic data of safety accident occurrence data and expert opinion by construction industry type. Through this, it is expected that risk index for safety accidents according to detailed types of works will be presented stochastically and it will be possible to predict the risk factors and the expected range of damage based on the reliability analysis in the construction safety management plan. It will also reduce many of the planning risks that are common to decision makers in the field of construction management. In identifying risks, road bridge construction was classified into earthworks, drainage works, and bridge construction, and possible safety accidents were classified based on expert data. The risk index was calculated for each detailed construction of road and bridge construction, drainage construction, and bridge construction.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.19-25
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• 2008

Nihombashi district, which is located in a heart of Tokyo Metropolitan area, has been flourished as a Japanese economic and cultural center since Tokyo was developed as a capital. Nihombashi district has still remained the Edo idea of stylishness since the government of Edo was established in 1603. During Edo period, population of Edo (former name of Tokyo) reached one million. Edo became one of big city around the world. Nihombashi district has been transformed as economical, financial and cultural center, along with modern transformation of Tokyo. During high economic growth (1955-1975), Nihombashi Bridge and River, which used to a symbol of Tokyo, have been covered with elevated highways. The river was polluted whereas the river does not have any relationship with people's daily activities. Since Japan has focused on environment concern in 80's, people and companies in Nihombashi district and Nihombashi River also requested to restore Nihombashi district and Nihombashi River. There are a lot of projects going on related to regenerate the river and the community, such as to remove highways covered with the river, restore river environment and run water navigation. This article mentioned to introduce the project of Nihombashi River and Nihombashi district that regenerate the community to capitalize history and geographic characteristics in Nihombashi district, to run water navigation through the river, and to review outcomes through various projects.

• Journal of KIBIM
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• v.1 no.1
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• pp.26-31
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• 2011

Due to the characteristics of 3D objects of building construction projects which have regular, vertical and repetitive shapes, the most practical utilization of BIM in the country is focused on building projects. The characteristics of 3D objects of civil engineering project have irregular, horizontal and non-repetitive shapes. Therefore, consisting of a practical BIM model is difficult comparing with building project. This study suggests an application process of BIM for the planning and design phases for civil engineering project. A BIM system is developed based on suggested BIM process and it is verified through a bridge construction project.

• Asian Journal of Innovation and Policy
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• v.1 no.1
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• pp.92-115
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• 2012

The problem Japanese universities face is exactly the same as that of German universities: no international recognition in world rankings of universities despite their high levels of postwar economic and technological developments. This was indeed one reason why world-class Japanese firms, such as Toyota and Sony, have avoided working closely with Japanese universities for R&D partnership and new technology commercialization. To resolve this problem, the Japanese government has continuously implemented aggressive policies of the internationalization, privatization, liberalization, and privatization of universities since the onset of the economic recession in 1989 in order to revitalize the Japanese economy through radical innovation projects between universities and firms. National projects of developing medical robots for Japan's ageing society are some of the ambitious examples that emphasize feed-forward learning in innovation. However, this paper argues that none of these programs of fostering university-firm alliances toward feed-forward learning has been successful in promoting the world ranking of Japanese universities, although they showed potentials of reinforcing their conventional strength of introducing $kaizen$ through feedback learning of tacit knowledge. It is therefore argued in this paper that Japanese universities and firms should focus on feedback learning as a way to motivate firm-university R&D alliances.

• Advances in concrete construction
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• v.10 no.1
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• pp.71-79
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• 2020

Ultra-high-performance concrete (UHPC) is recognized as a promising material in future civil engineering projects due to its outstanding mechanical and durability properties. However, the lack of local UHPC materials and official standards, especially for prestressed UHPC structures, has limited the application of UHPC. In this research, a large-scale prestressed bridge girder composed of nonproprietary UHPC is produced and investigated. This work has two objectives to develop the mixing procedure required to create UHPC in large batches and to study the flexural behavior of the prestressed girder. The results demonstrate that a sizeable batch of UHPC can be produced by using a conventional concrete mixing system at any precast factory. In addition, incorporating local aggregates and using conventional mixing systems enables regional widespread use. The flexural behavior of a girder made by this UHPC is investigated including flexural strength, cracking pattern and development, load-deflection curve, and strain and neutral axis behaviors through a comprehensive bending test. The experimental data is similar to the theoretical results from analytical methods based on several standards and recommendations of UHPC design.