Analisa Bending Stress pada Submerged Floating Tunnel

Perhitungan dengan pemodelan Submerged Floating Tunnel (SFT) dengan menggunakan perangkat lunak berbasis metode elemen hingga. Analisa struktur terowongan apung menggunakan prinsip kerja dengan mendiskripsikan seluruh beban (force) pada SFT berupa beban internal dan eksternal yang bekerja akan diperoleh momen reaksi yang terjadi sepanjang badan SFT, dengan mengetahui luas penampang melintang SFT maka dapat diperoleh bending stress di seluruh badan SFT.Keywords : submerged floating tunnel (SFT), bending stress, structural analysi

Design of Immersed Tunnel and How We Research Submerged Floating Tunnel

This chapter begins with the discussion of the immersed tunnel design, concerning its reason of existence, historical review, general design, transverse and longitudinal design, the interaction, and the critical issues. The discussion is founded on the author’s 10 year experience in building the Hong Kong-Zhuhai-Macao Bridge (HZMB) immersed tunnel as a site design engineer. The experience of building immersed tunnel is transferable to build the submerged floating tunnel, which has never been built. In author’s opinion, the submerged floating tunnel (SFT) technique will be the next generation of IMT technique. In the second part of this chapter, the author proceeds to discuss the strategy of SFT research and the latest development in CCCC SFT Technical Joint Research Team

Load-unload response ratio and its application to estimate future seismicity of Qiandao Lake region

AbstractLURR (Load-Unload Response Ratio) has been introduced briefly in this paper and future seismicity of Qiandao Lake region has been predicted in terms of LURR for the purpose of SFT (Submerged Floating Tunnel) project

Analysis Mooring System Configuration of Submerged Floating Tunnel

Submerged Floating Tunnels (SFT) is a tubular structure that is submerged and floating in depth remains through the system of anchors consisting of a cable connected to the seabed. SFT structure imposed its own weight and is assisted by the buoyancy or uplift caused by water, cross sectin of the tunnel is designed so that buoyancy can overcome the structural weight and experienced a lift force that causes the floating structure. Fastening system (mooring system) also play a role which is to inhibit the SFT structure, minimize displacement and stress caused by environmental burden, such as earthquakes and hydrodynamic load that can aggravate the condition SFT structure in case of crossing the sea with SFT system. SFT will give a fairly small impact on the environment as it floated in the water, and with built using a modular system, the SFT (Submerged Floating Tunnels) can reach a distance long enough and does not cause pollution. Basically the same as the force that occurs archimides principle, where the objects are in the water to get a compressive force to the top. Cross sectional analysis SFT, will be modeled by 7 different models that have been in previous studies. The model\u27s of SFT with steel cable to hold the structure in order to remain strong with the inclination selected. Analysis is done by modeling the triangle wiring configuration with different angle of incliflation cable. The analysis by comparing the test model were made earlier with prototype analyzed numerically. The expected structure did not undergo excessive deformation due to the environmental burden. Therefore, the structure of the SFT will be done with the Abaqus as finite element analysis. So, obvious deformation occurred in the cable. Therefore, it was expected to obtain the optimum angle of inclination was 54º

CONSTRUCTION CHALLENGE OF SUBMERGED FLOATING TUNNEL IN INDONESIA

Indonesia is an archipelagic country which consisting of many islands that require competitive crossing technology. Submerged floating tunnel (SFT) responds to this challenge and comes as a competitive crossing technology. SFT structure has superior advantages to conventional crossing technologies but it also has some disadvantages especially in keeping structural stability.Structural stability of SFT is mainly effected by site characterization and environmental disturbances. Geographical combination of water depth, crossing distance and overall dimension is one of the most important factors to decide the structu of Engimeeral design as well as environmental disturbances such as wave, current and earthquake.This paper presents descriptions of SFT structures, some of the SFT structure challenges and the opportunities of using SFT structures for various purposes in Indonesia

Impact analysis of submerged floating tunnel for external collision

Submerged floating tunnel is an innovative tunnel infrastructure passing through the deep sea independent of wave and wind so that high speed vehicle or train can run. It doesn't depend on water depth and is cost effective due to modular construction on land. The construction period can be reduced drastically. In this paper, a concept design of submerged floating tunnel is introduced and a method to analyze structural behavior of the body in case of collision with ships or submarines is proposed for securing safety. In this study, the local damage and global behavior of submerged tunnel in collision with submerged moving body are simulated via commercial hydrocode ANSYS LS-DYNA. In simulations, a conceptual tunnel section prepared in Korea is considered and various penetration and deformation responses with respect to impact velocity, applied materials and collision scenarios are obtained. Finally, for a conceptual design of submerged floating tunnel, maximum deformation, bending moment and impact forces are analyzed based on force and energy equilibrium

Analysis Mooring System Configuration of Submerged Floating Tunnel

Submerged Floating Tunnels (SFT) is a tubular structure that is submerged and floating in depth remains through the system of anchors consisting of a cable connected to the seabed. SFT structure imposed its own weight and is assisted by the buoyancy or uplift caused by water, cross sectin of the tunnel is designed so that buoyancy can overcome the structural weight and experienced a lift force that causes the floating structure. Fastening system (mooring system) also play a role which is to inhibit the SFT structure, minimize displacement and stress caused by environmental burden, such as earthquakes and hydrodynamic load that can aggravate the condition SFT structure in case of crossing the sea with SFT system. SFT will give a fairly small impact on the environment as it floated in the water, and with built using a modular system, the SFT (Submerged Floating Tunnels) can reach a distance long enough and does not cause pollution. Basically the same as the force that occurs archimides principle, where the objects are in the water to get a compressive force to the top. Cross sectional analysis SFT, will be modeled by 7 different models that have been in previous studies. The model's of SFT with steel cable to hold the structure in order to remain strong with the inclination selected. Analysis is done by modeling the triangle wiring configuration with different angle of incliflation cable. The analysis by comparing the test model were made earlier with prototype analyzed numerically. The expected structure did not undergo excessive deformation due to the environmental burden. Therefore, the structure of the SFT will be done with the Abaqus as finite element analysis. So, obvious deformation occurred in the cable. Therefore, it was expected to obtain the optimum angle of inclination was 54º

Analisa Konfigurasi Mooring Sistem Pada Submerged Floating Tunnel(SFT)

Submerged Floating Tunnel (SFT) merupakan sebuah struktur tubular yang terendam dan mengambang di kedalaman tetap melalui sistem angkur yang terdiri dari kabel yang terhubung ke dasar laut. Terowongan secara permanen dikenakan berat sendiri dan dibantu dengan adanya daya apung yang ditimbulkan oleh air, Penampang terowongan didesain sehingga daya apung dapat mengatasi berat badan struktural dan mengalami kekuatan volume yang diarahkan ke atas. Sistem kabel juga memainkan peran yaitu untuk menghambat terowongan, meminimalkan perpindahan dan tegangan yang disebabkan oleh beban lingkungan, seperti beban gempa dan hidrodinamik yang dapat menjadi runtuh dalam kasus penyeberangan laut dengan sistem SFT (Submerged Floating Tunnel ) oleh karena itu, kabel sangat berperan dalam menstabilkan posisi SFT (Submerged Floating Tunnel ). karena itu, maka SFT (Submerged Floating Tunnel ) akan dipasang kabel baja untuk menahan struktur agar tetap kokoh. Sehingga struktur tidak mengalami pergoyangan berlebih akibat beban lingkungan. Kabel dimodelkan dengan berbagai konfigurasi yaitu dengan posisi sudut 00, 90, 180, 270, 360, 450, 540, 630, dan 720. Dalam pemodelan dengan metode numerik menggunakan software ABAQUS v6.14. dimana pemodelan sesuai dengan data lingkungan pada kepulauan seribu yaitu antara pulau panggang dan pulau karya. Pemodelan yang dibuat dibandingkan dengan penelitian sebelumnya menggunakan software SAP2000. Namun halnya, pada pemodelan dengan ABAQUS menggunakan load yaitu increment displacement yang dimungkinkan sampai elemen mengalami leleh. Hasil analisa elemen menunjukkan bahwa konfigurasi kabel yang efektif yaitu konfigurasi kabel dengan sudut inklinasi sudut 54⁰. Pada kondisi ini, tegangan dan perpindahan yang dihasilkan menunjukkan nilai yang relatif kecil dibandingkan dengan konfigurasi kabel yang lain. Tegangan yang terjadi pada sudut inklinasi kabel 54⁰ yaitu 1625 Mpa. Perpindahan yang terjadi pada sudut inklinasi kabel 54⁰ yaitu 25mm. Selain itu, terlihat juga pada hasil verifikasi antara ABAQUS dan Sap 2000 menghasilkan nilai yang relatif dekat. Maka dapat disimpulkan ABAQUS dapat digunakan dalam pemodelan elemen apapun yang akan diaplikasikan dalam kehidupan sehari hari. ====================================================================================================== Submerged Floating Tunnel (SFT) is a tubular structure that is submerged and floated in the certain depths through the system of anchors consisting of a cable connected to the seabed. The tunnels are permanently subjected to its own weight and assisted by the buoyancy caused by the water, a cross-section of the tunnel is designed so that buoyancy can overcome the structural weight and experience the power of volume directed upwards. The cable system also plays a role which is to inhibit the tunnel, minimizing displacement and stress caused by environmental loads, such as earthquake loads and hydrodynamic that can be collapsed in the case of sea crossings with the system SFT (Submerged Floating Tunnel), therefore, the cable was instrumental in stabilizing position SFT (Submerged Floating Tunnel). Therefore, the SFT (Submerged Floating Tunnel) will be installed steel cables to hold the structure in order to remain solid. So that the structure did not experience excessive displacement due to the environmental burden. Cables modeled with various configurations, namely with the position angle of 00, 90, 180, 270, 360, 450, 540, 630, and 720. In numerical modeling method using ABAQUS v6.14. which according to the environmental data on Kepulauan Seribu, it is between Panggang island and Karya island. The modeling was compared to a previous study using SAP2000. However, the modeling by ABAQUS using load incremental displacement is possible being yield. The results show that the software output cable configuration is effective that the cable configuration at an inclination angle 54⁰. In this condition, the stress and the displacement showed the smallest value compared with other cable configurations. The stress of cable at an inclination angle 54o is 1625 Mpa and the displacement is 25 mm. Also the verification results between ABAQUS and Sap 2000 resulted in a relatively close value. It can be concluded ABAQUS can be used in the modeling of any elements that would be applied in their daily lives

Researches on essential mechanics issues for submerged floating tunnel

Since 2001, a research group in the Institute of Mechanics, Chinese Academy of Sciences, has been devoted to the research of essential mechanics issues for submerged floating tunnel (SFT). In addition to the structural design of the SFT prototype in Qiandao Lake, the relevant researches cover a number of topics. This paper briefly describes the research procedure and results, including dynamic response of SFT due to surface wave, vortex-induced vibration of anchoring system, structural analysis of curved SFT, temperature effects of curved SFT, structural dynamic response due to accidental load, and effects of structural parameters (buoyancy-weight ratio, tunnel length，tether stiffness，etc.) on dynamic response

Hydroelastic Response of Submerged Floating Tunnel

This research investigation addresses the analysis and numerical simulation of dynamic response of submerged floating tunnels (SFTs) under the influence of surface waves. As an innovative technical solution for waterway crossings, an SFT is usually considered as a slender structure restrained by cable system due to its large aspect ratio, i.e. ratio of length to diameter. Although an SFT is usually placed at a certain depth under the water surface, it is still susceptible to wave field due to its slenderness. In this research study, a three-dimensional finite element solving technique, using both Morison’s equation and modal analysis, is formulated to construct a hydroelastic model of an SFT and to determine its deformation considering the fluid-structure interactions. Two preliminary tunnel models for China and Japan, respectively, were studied by implementing the proposed methodology. In the first case study, a three-dimensional finite element model of the SFT prototype in Qiandao Lake (China) was built in Matlab and subsequently analyzed using mode decomposition to determine its natural frequencies and mode shapes. For each mode shape, Morison’s equation was employed to calculate fluid forces at each cross section along the tunnel for given surface wave conditions. Then in the frequency domain, a complex equation of motion was solved iteratively to address the convergence of the stiffness of the cable system. The total dynamic response of SFT was the sum of contributions from each mode component. Results obtained from Matlab were compared with findings from previous publications and numerical simulations in ABAQUS. Next, a generic pedestrian-aimed SFT proposed for Otaru Crossing in Japan was studied. Parametric studies were performed to evaluate the influence of configuration scheme of cable system and tunnel submerged depth on the dynamic response of SFT. Results show the importance of fundamental structural parameters in the SFT global performance and several key conclusions regarding parameter selections were drawn for engineering practices in design phase