• 국제학술발표논문집
• /
• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
• /
• pp.586-590
• /
• 2011

This paper presents the case study of the CE by collaborative system and proposes a model of the CM group for the cable supported bridge. The cable supported bridges have a large project scale and need a high level of construction method. Therefore an advanced construction management system is required for successful completion of project. The construction management (CM) group which control design management, construction plan, subcontract, technical support and R&D is organized for the cable supported bridge project. The CM group established a collaborative system with construction site and drew an effective management of cost, process, quality, safety for each project. Furthermore, the CM group established the procedure of construction management based on the construction engineering (CE) items and performed the project management on the construction phase. Efficiency of cost reduction and site control is maximized by using a collaborative system.

• Structural Engineering and Mechanics
• /
• 제24권3호
• /
• pp.339-354
• /
• 2006

Hangzhou Bay Bridge spans the Hangzhou Bay and is located at Zhejiang province in the southeast seacoast of China. The total length of the bridge is 36 km. The bridge is composed of bridge approaches made up of multi-span prestressed concrete box girders and two cable-stayed bridges over the north and south navigable spans respectively. The seismic response analysis of the bridge model shows that if the navigable spans are designed as the routine earthquake-resistance system, the displacements and internal forces in pylons, piers and deckes are too large to satisfy the anti-seismic requirement of the structure. Therefore, the seismic reduction design was carried out by using viscous dampers to dissipate the kinetic energy of the structure both longitudinally and transversely. Using the vibration reduction system and aiming at the reasonable optimal goal, the purpose to reduce the seismic responses in south and north navigable spans has been achieved.

• Structural Engineering and Mechanics
• /
• 제29권2호
• /
• pp.171-186
• /
• 2008

The seismic response analysis of an existing bridge needs a mathematical model that can be calibrated with measured dynamic characteristics. These characteristics are the periods and the associated mode shapes of vibration and the modal damping coefficients. This paper deals with the measurements and the interpretation of the results of ambient vibration tests done on a newly erected cable stayed bridge across the Oued Dib River at Mila city in Algeria. The signal analysis of ambient vibration records will permit to determine the dynamic characteristics of the bridge. On the other hand, a 3-D model of the bridge is developed in order to assess the frequencies and the associated modes of vibration. This information will be necessary in the planning of the test on the site (locations of the sensors, frequencies to be measured and the associated mode shapes of vibration). The frequencies predicted by the finite element model are compared with those measured during full-scale ambient vibration measurements of the bridge. In the same way, the modal damping coefficients obtained by the random decrement method are compared to those of similar bridges.

• Structural Engineering and Mechanics
• /
• 제69권3호
• /
• pp.269-281
• /
• 2019

This work addresses a three-dimensional nonlinear structural analysis of the constructive phases of a cable-stayed segmental concrete bridge using The Finite Element Method through ANSYS, version 14.5. New subroutines have been added to ANSYS via its UPF customization tool to implement viscoelastoplastic constitutive equations with cracking capability to model concrete's structural behavior. This numerical implementation allowed the use of three-dimensional twenty-node quadratic elements (SOLID186) with the Element-Embedded Rebar model option (REINF264), conducting to a fast and efficient solution. These advantages are of fundamental importance when large structures, such as bridges, are modeled, since an increasing number of finite elements is demanded. After validating the subroutines, the bridge located in Rio de Janeiro, Brazil, and known as "Ponte do Saber" (Bridge of Knowledge, in Portuguese), has been numerically modeled, simulating each of the constructive phases of the bridge. Additionally, the data obtained numerically is compared with the field data collected from monitoring conducted during the construction of the bridge, showing good agreement.

• Wind and Structures
• /
• 제27권6호
• /
• pp.357-368
• /
• 2018

For a long cable-stayed bridge, stay cables are its most important load-carrying components. In this paper, long-term monitoring of super-long stay cables of Sutong Bridge is introduced. A comprehensive data analysis procedure is presented, in which time domain and frequency domain based analyses are carried out. In time domain, the vibration data of several long stay cables are firstly analyzed and the standard deviation of the acceleration of stay cables, and its variation with time are obtained, as well as the relationship between in-plane vibration and out-plane vibration. Meanwhile, some vibrations such as wind and rain induced vibration are detected. Through frequency domain analysis, the basic frequencies of the stay cables are identified. Furthermore, the axial forces and their statistical parameters are acquired. To investigate the vibration deflection, an FFT-based decomposition method is used to get the modal deflection. In the end, the relationship between the vibration amplitude of stay cables and the wind speed is investigated based on correlation analysis. Through the adopted procedure, some structural parameters of the stay cables have been derived, which can be used for evaluating the component performance and corresponding management of stay cables.

• Wind and Structures
• /
• 제32권3호
• /
• pp.179-191
• /
• 2021

A series of wind tunnel tests, including 1:50 sectional model tests, 1:50 free-standing bridge tower tests and 1:70 full-bridge aeroelastic model tests were carried out to systematically investigate the aerodynamic performance of the Hong Kong-Zhuhai-Macao Bridge (HZMB). The test result indicates that there are three wind-resistant safety issues the HZMB encounters, including unacceptable low flutter critical wind speed, vertical vortex-induced vibration (VIV) of the main girder and galloping of the bridge tower in across-wind direction. Wind-induced vibration of HZMB can be effectively suppressed by the application of aerodynamic and mechanical measures. Acceptable flutter critical wind speed is achieved by optimizing the main girder form (before: large cantilever steel box girder, after: streamlined steel box girder) and cable type (before: central cable, after: double cable); The installations of wind fairing, guide plates and increasing structural damping are proved to be useful in suppressing the VIV of the HZMB; The galloping can be effectively suppressed by optimizing the interior angle on the windward side of the bridge tower. The present works provide scientific basis and guidance for wind resistance design of the HZMB.

• 한국구조물진단유지관리공학회 논문집
• /
• 제17권2호
• /
• pp.54-61
• /
• 2013

사장교 케이블은 초기 큰 인장력으로 축강성이 매우 크지만, 횡방향 휨강성은 약하다. 풍하중이나 교통하중은 케이블을 심각하게 진동시켜 사장교의 사용성에 부정적 영향을 끼친다. 그러므로 장대교량에 감쇠장치를 설치하는 진동 저감 계획이 절실히 요구된다. 마찰댐퍼는 교통하중이나 풍하중과 같은 동적하중이 작용하는 케이블 진동에서 진폭과 지속시간을 대폭 감소시킬 수 있는 효과적인 장치임을 알 수 있다. 케이블 진동은 댐퍼제작방법과 설치위치 및 형상에 따라 효율이 달라질 수 있다. 그럼에도 불구하고 본 실험연구의 마찰댐퍼 설치전 후 제진성능효과 분석결과는 향후 사장케이블의 진동을 저감시키는 기본 자료로 활용할 수 있다.

• Structural Engineering and Mechanics
• /
• 제71권6호
• /
• pp.603-625
• /
• 2019

Main cable configurations under final dead load and in the unloaded state and critical construction parameters (e.g. unstrained cable length, unstrained hanger lengths, and pre-offsets for tower saddles and splay saddles) are the core considerations in the design and construction control of a suspension bridge. For the purpose of accurate calculations, it is necessary to take into account the effects of cable strands over the anchor spans, arc-shaped saddle top, and tower top pre-uplift. In this paper, a method for calculating the cable configuration under final dead load over a main span, two side spans, and two anchor spans, coordinates of tangent points, and unstrained cable length are firstly developed using conditions for mechanical equilibrium and geometric relationships. Hanger tensile forces and unstrained hanger lengths are calculated by iteratively solving the equations governing hanger tensile forces and the cable configuration, which gives careful consideration to the effect of hanger weight. Next, equations for calculating the cable configuration in the unloaded state and pre-offsets of saddles are derived from the cable configuration under final dead load and the conditions for unstrained cable length to be conserved. The equations for the main span, two side spans and two anchor spans are then solved simultaneously. In the proposed methods, coupled nonlinear equations are solved by turning them into an unconstrained optimization problem, making the procedure simplified. The feasibility and validity of the proposed methods are demonstrated through a numerical example.

• Smart Structures and Systems
• /
• 제23권5호
• /
• pp.449-466
• /
• 2019

Cable-stayed bridges are attractive due to their beauty, reducing material consumption, less harm to the environment and so on, in comparison with other kinds of bridges. As a massive structure with long period and low damping (0.3 to 2%) under many dynamic loads, these bridges are susceptible to fatigue, serviceability disorder, damage or even collapse. Tuned Mass Damper (TMD) is a suitable controlling system to reduce the vibrations and prevent the threats in such bridges. In this paper, Multi Tuned Mass Damper (MTMD) system is added to the Ahvaz cable stayed Bridge in Iran, to reduce its seismic vibrations. First, the bridge is modeled in SAP2000 followed with result verification. Dead and live loads and the moving loads have been assigned to the bridge. Then the finite element model is developed in OpenSees, with the goal of running a nonlinear time-history analysis. Three far-field and three near-field earthquake records are imposed to the model after scaling to the PGA of 0.25 g, 0.4 g, 0.55 g and 0.7 g. Two MTMD systems, passive and active, with the number of TMDs from 1 to 8, are placed in specific points of the main span of bridge, adding a total mass ratio of 1 to 10% to the bridge. The parameters of the TMDs are optimized using Genetic Algorithm (GA). Also, the optimum force for active control is achieved by Fuzzy Logic Control (FLC). The results showed that the maximum displacement of the center of the bridge main span reduced 33% and 48% respectively by adding passive and active MTMD systems. The RMS of displacement reduced 37% and 47%, the velocity 36% and 42% and also the base shear in pylons, 27% and 47%, respectively by adding passive and active systems, in the best cases.

• 한국조경학회지
• /
• 제29권6호
• /
• pp.11-20
• /
• 2002

This study aims to discover the landscape image of bridges and their harmonization wish surrounding sceneries. This research utilized the basic study tool of psycho-physics and processed the case study of five types of bridges on the Han-River, Seoul. Twenty-one bridges on Han-River were classified into five categories ; the cable stayed bridge, the arch bridge, the girder bridge, the trust bridge and the suspension bridge. Also, aesthetic elements of the bridges including the form the texture, the color, the scale and the harmony were examined. The questionaires to analysis the image and harmonization with surrounding sceneries were designed using semantic differential scale and 5 point Likert scale. The results of the research were as follows. First, components representing the images of bridge landscape are classified into three types, ‘beauty’, ‘weightfulness’ and ‘friendliness’. Second, the image of each bridge as a whole turns out not to be different from each other but to be different in the context of neighboring sceneries. It was also determined that both the Cable Stayed Bridge type and the Arch Bridge type are the most attractive. But, the former does have a more masculine image, and the latter has a m[n feminine image. Third, the Cable Stayed Bridge and the Arch Bridge were evaluated highly in terms of harmonization with surrounding landscapes, while the Girder Bridge received the lowest evaluation. All of the above results suggest that the bridges should be constructed not only for beauty itself in form, color, texture and scale, but also in harmonization with the surrounding landscape. Lastly, it is desirable to do further research to find out sort specific design principles that exist between bridges and tangible surrounding landscape types.