• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.819-824
• /
• 2010

Model test was performed for new earth retention system that is a kind of truss tower with non-supported excavation. For the model test, a dimensional analysis of the full-scaled truss tower system was performed. The horizontal displacement of the wall, bending stress acting on TTS system were measured during construction simulation. From the measurements, the performance of the truss tower system was investigated.

• Steel and Composite Structures
• /
• v.32 no.2
• /
• pp.189-198
• /
• 2019

This paper aims to study the mechanical performance of three-tower four-span suspension bridges with steel truss girders, including the static and dynamic characteristics of the bridge system, and more importantly, the influence of structural parameters including the side-main span ratio, sag-to-span ratio and the girder stiffness on key mechanical indices. For this purpose, the Oujiang River North Estuary Bridge which is a three-tower four-span suspension bridge with two main spans of 800m under construction in China is taken as an example in this study. This will be the first three-tower suspension bridge with steel truss girders in the world. The mechanical performance study and parametric analysis are conducted based on a validated three-dimensional spatial truss finite element model established for the Oujiang River North Estuary Bridge using MIDAS Civil. It is found that a relatively small side-main span ratio seems to be quite appropriate from the perspective of mechanical performance. And decreasing the sag-to-span ratio is an effective way to reduce the horizontal force subjected to the midtower and improve the antiskid safety of the main cable, while the vertical stiffness of the bridge will be reduced. However, the girder stiffness is shown to be of minimal significance on the mechanical performance. The findings from this paper can be used for design of three-tower suspension bridges with steel truss girders.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1994.04a
• /
• pp.49-56
• /
• 1994

The purpose of this study is to construct a total design & manufacturing system for the Space-Truss structure. In this study, we choose the transmission tower as the study model to show the possibility of a Total System for another space truss structure. We are confident that this total system should provide more convenience, accuracy and should help to save time from the design stage to construct stage of the transmission tower.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.09a
• /
• pp.1317-1323
• /
• 2009

A finite element analysis was performed for new earth retention system that is a kind of truss tower with non-supported excavation. A 2D finite element model was adopted in this study to investigate the behavior of the earth retention system. Just because this non-supported truss tower system is too complex to model in 2D plain-strain condition to itself, so have to simplify it by the conception of equivalent rigidity. The horizontal displacement of the wall and lateral earth pressure distribution on the wall were computed. And it is compared with NAVFAC design manual.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.09a
• /
• pp.1324-1329
• /
• 2009

Needs for underground space development and utilization have been increasing in urban area. The conventional strutting method in excavation is effective to restrain the ground movements and displacements of earth structures but inefficient for workers because of small working space. The conventional earth reinforcement methods such as earth-anchor and soil-nailing also have limitation to apply in urban area due to threats to stability of adjacent buildings around excavation boundaries. Recently, many types of earth retaining structures are being developed to overcome disadvantages of conventional excavation methods in urban area. In this study, a series of numerical analyses were performed with MIDAS GTS, geotechnical analysis program and MIDAS Civil, structural analysis design program to evaluate behavior and stability of the new type of non-supporting earth retaining structure, called Temporary Tower System (TTS), consisting of tower truss structures with much economical and spatial advantage.

• Earthquakes and Structures
• /
• v.7 no.4
• /
• pp.571-586
• /
• 2014

This paper presents experimental and numerical study on seismic performance of a super tall steel tower structure. The steel tower, with a height of 388 meters, employs a steel space truss with spiral steel columns to serve as its main lateral load resisting system. Moreover, this space truss was surrounded by the spiral steel columns to form a steel mega system in order to support a 12-story platform building which is located from the height of 230 meters to 263 meters. A 1/40 scaled model for this tower structure was made and tested on shake table under a series of one- and two-dimensional earthquake excitations with gradually increasing acceleration amplitudes. The test model performed elastically up to the seismic excitations representing the earthquakes with a return period of 475 years, and the test model also survived with limited damages under the seismic excitations representing the earthquakes with a return period 2475 years. A finite element model for the prototype structure was further developed and verified. It was noted that the model predictions on dynamic properties and displacement responses agreed reasonably well with test results. The maximum inter-story drift of the tower structure was obtained, and the stress in the steel members was investigated. Results indicated that larger displacement responses were observed for the section from the height of 50 meters to 100 meters in the tower structure. For structural design, applicable measures should be adopted to increase the stiffness and ductility for this section in order to avoid excessive deformations, and to improve the serviceability of the prototype structure.

• International Journal of High-Rise Buildings
• /
• v.6 no.3
• /
• pp.217-226
• /
• 2017

This paper summarizes the structural concept and design of the "Nakanoshima Festival Tower West" in Osaka, Japan, which is 200m high and has a super-high damping system. Its superstructure is mainly composed of a central core and outer tube frames. It has a bottom truss structure at the boundary between the low-rise and mid-rise sections of the building, where the column arrangement is changed. Besides, the high-rise section of the building has a neck truss structure. These truss structures smoothly transfer the axial forces of the columns and reduce the flexural deformations induced by horizontal loads. Oil dampers with extremely high damping capacity are installed in the rigid walls named the "Big Wall Frames" of the low-rise section. Moreover, many braces and damping devices are well arranged in the center core of each story. The damping effects of these devices ensure that all structural members are remain within the elastic range and that story drifts are within 1/150 in large earthquakes. This super-high damping structure in the low-rise section is named the "Damping Layer". The whole structural system is named the "Super Damping Structure". The whole structural systems enhance the building's safety, comfort and Business Continuity Planning (BCP) under large earthquakes.

• International Journal of High-Rise Buildings
• /
• v.7 no.3
• /
• pp.255-264
• /
• 2018

This paper introduces three distinctive means for the use of a 189-meter high damped structure ensuring safety against earthquake: 1. Realization of L-shaped elevational structural planning: The bottom and top of the tower have belt trusses and hat trusses respectively to restrain the bending deformation. Furthermore, large-capacity oil dampers (damping force 6,000 kN) are installed in the middle part of the tower to restrain the higher-mode deformation. 2. Realization of L-shaped planar structural planning: We devised a means of matching the centers of gravity and rigidity by adjusting planar rigidity. Moreover, viscous damping devices are located at the edges of the L-shaped plan, where torsional deformation tends to be amplified. We call this the "Damping Tail" system. 3. Composite foundation to equalize deformations under different loading conditions: We studied the vertical and horizontal deformations using sway-rocking and 3D FEM models including the ground, and applied multi-stage diameter-enlarged piles to the tower and a mat foundation to the podium to keep the foundations from torsional deformations and ensure structural safety.

• International Journal of High-Rise Buildings
• /
• v.3 no.3
• /
• pp.173-183
• /
• 2014

Nakanoshima Festival Tower is a 200 m high-rise complex building which contains a renewed 2700-seat capacity concert hall known as "Festival Hall" and offices including headquarter of a news company. In order to build up an office tower on the hall which requires large open space, a giant truss system is employed. The giant trusses being composed of mega-trusses and belt-trusses support all the building weight above them and transfer the load to the outside of the hall. The building also requires high seismic resistance performance for a news company. Application of mid-story seismic isolation enables the building to satisfy high-level seismic resistance criteria.

• Structural Engineering and Mechanics
• /
• v.64 no.2
• /
• pp.183-194
• /
• 2017

This paper presents the experimental investigation into a new type of steel-concrete hybrid outrigger system developed for the high-rise building structure. The steel truss is embedded into the reinforced concrete outrigger wall, and both the steel truss and concrete outrigger wall work compositely to enhance the overall structural performance of the tower structures under extreme loads. Meanwhile, metal dampers of low-yield steel material were also adopted as a 'fuse' device between the hybrid outrigger and the column. The damper is engineered to be 'scarified' and yielded first under moderate to severe earthquakes in order to protect the structural integrity of important structural components of the hybrid outrigger system. As such, not brittle failure is likely to happen due to the severe cracking in the concrete outrigger wall. A comprehensive experimental research program was conducted into the structural performance of this new type of hybrid outrigger system. Studies on both the key component and overall system tests were conducted, which reveal the detailed structural response under various levels of applied static and cyclic loads. It was demonstrated that both the steel bracing and concrete outrigger wall are able to work compositely with the low-yield steel damper and exhibits both good load carrying capacities and energy dispersing performance through the test program. It has the potential to be applied and enhance the overall structural performance of the high-rise structures over 300 m under extreme levels of loads.