• Smart Structures and Systems
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• v.15 no.3
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• pp.807-830
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• 2015

When a building structure requires both health monitoring system and vibration control system, integrating the two systems together will be cost-effective and beneficial for creating a smart building structure with its own sensors (nervous system), processors (brain system), and actuators (muscular system). This paper presents a real-time integrated procedure to demonstrate how health monitoring and vibration control can be integrated in real time to accurately identify time-varying structural parameters and unknown excitations on one hand, and to optimally mitigate excessive vibration of the building structure on the other hand. The basic equations for the identification of time-varying structural parameters and unknown excitations of a semi-active damper-controlled building structure are first presented. The basic equations for semi-active vibration control of the building structure with time-varying structural parameters and unknown excitations are then put forward. The numerical algorithm is finally followed to show how the identification and the control can be performed simultaneously. The results from the numerical investigation of an example building demonstrate that the proposed method is feasible and accurate.

• Structural Engineering and Mechanics
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• v.90 no.5
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• pp.493-504
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• 2024

This paper presents the methodology and results for the investigation of the structural safety of 40 aged underground water tanks to support the weight of photovoltaic (PV) systems that were supposed to be placed on their roof reinforced concrete (RC) slabs. The investigation procedure included (1) review of available documents; (2) visual inspection of the roof RC slabs; (3) carrying out a series of nondestructive (ND) tests; and (4) analysis of results. Out of the 40 tanks, eleven failed the visual inspection phase and were discarded from further investigation. The roof RC slabs of the tanks that passed the visual inspection were subjected to a series of ND tests that included infrared thermography, impact echo, ultrasonic pulse velocity (UPV), Schmidt hammer, concrete core compressive strength, and water-soluble chloride content. The NDT results proved that eight more tanks were not suitable to support the PV systems. Based on the results of the visual inspection and testing, a probabilistic decision-making criterion was established to reach a decision regarding the structural integrity of the roof slabs. The study concluded that the condition of the drainage filter was essential in protecting the tanks and its intact presence can be used as a strong indication of the structural integrity of the roof RC slabs.

• Smart Structures and Systems
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• v.7 no.5
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• pp.349-363
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• 2011

To assess the performance of a structure requires the measurement of global and relative displacements at critical points across the structure. They should be obtained in real time and in all weather condition. A Global Navigation Satellite System (GNSS) could satisfy the last two requirements. The American Global Position System (GPS) provides long term acquisitions with sampling rates sufficient to track the displacement of long period structures. The accuracy is of the order of sub-centimetres. The steel building which hosts the authors' laboratory is the reference case-study within this paper. First a comparison of data collected by GPS sensor units with data recorded by tri-axial accelerometers is carried out when dynamic vibrations are induced in the structure by movements of the internal bridge-crane. The elaborations from the GPS position readings are then compared with the results obtained by a Finite Element (FE) numerical simulation. The purposes are: i) to realize a refinement of the structural parameters which characterize the building and ii) to outline a suitable way for processing GPS data toward structural monitoring.

• International Journal of High-Rise Buildings
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• v.12 no.4
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• pp.307-320
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• 2023

Tall buildings are built with an abundant amount of materials, including structural materials, coming from our limited natural resources. Tall buildings that began from about 10-story tall office towers have evolved to over 150-story tall mixed-use megastructures. As a building becomes taller, structural material requirement to resist lateral wind loads becomes exponentially larger. Therefore, it is crucial to employ efficient structural systems and optimize their design, which will contribute to sustainable vertical built environments through preservation of resources. Tube type structures with large perimeter diagonals are among the most efficient structural systems for tall buildings. Developments of braced tube, braced megatube, diagrid structures, and their optimal design strategies are reviewed. Superframed conjoined towers, produced by interconnecting multiple clustered braced tubes, are presented as a new design direction to achieve not only structural but also architectural and social sustainable design goals.

• Architectural research
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• v.24 no.3
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• pp.75-84
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• 2022

Scads of earthquake-resistant systems are being invented around the globe to ensure structural resistance against the lateral forces induced by earthquake loadings considering structural safety, efficiency, and economic aspects. Shear wall and Bracing systems are proved to be two of the most viable solutions for seismic strengthening of structures. In the present study, three numerical models of a G+10 storied building are developed in commercial building analysis software considering shear wall and bracing systems for earthquake resistance. Material nonlinearity is introduced by using plastic hinges. Analyses are performed utilizing two dynamic methods: Response Spectrum analysis and nonlinear Time-history analysis using Kobe and Loma Prieta earthquake data and results are compared to observe the nonlinear behavior of structures. The outcomes exposed that a significant increase in the seismic responses occurs due to the nonlinearity in the building systems. It was also found that building with shear wall exhibits maximum resistance and minimum nonlinearity when subjected to dynamic loadings.

• International Journal of High-Rise Buildings
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• v.10 no.3
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• pp.179-191
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• 2021

Tall buildings have generally been developed as solo towers. With the increase of the heights of tall buildings from about 10-story buildings to supertall and megatall buildings, their structural systems have evolved from interior structures to exterior structures and combined/mixed systems. This paper reviews structural systems developed for solo supertall and megatall buildings and discusses the challenges they face in terms of structural performance and architectural design as the building heights are ever increased. As a viable and more sustainable design alternative to extremely tall solo towers, superframed conjoined towers are presented. Their structural performances are investigated in comparison with solo tower structures. Further, architectural potentials of superframed conjoined towers are explored through design studies.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.04a
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• pp.79-84
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• 1992

An integrated design system has as its aim the incoporation of all the design processes, such as, planning, preliminary design, analysis, detailed design (mamber design), evaluation, and drafting into an unified software system. Successful implementation such a system could lead to major improvements in efficiency by eliminating duplication of data and efforts. reducing errors, saving design time, providing management support, and so on. This study presents a methodology for an computer-integrated design system for building structures, synthesizing algorithmic procedures and knowledge based expert systems on the network database. Network database, which was designed to store all information systematically during the design processes, provides centeral communication area between algorithms and expert systems. The conventional procedural codes automate the routine design phases such as structural analysis, whereas knowledge-based expert systems support designer's decisions at the creative design phases such as preliminary design etc. The user interface with interactive and batch modes controls the design phases and manages design information and activates the algorithms and the expert systems. The concept presented in this paper will contribute to the formulation of automated design systems for building structures.

• International Journal of High-Rise Buildings
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• v.4 no.3
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• pp.209-217
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• 2015

Outrigger systems are highly efficient since they utilize the perimeter zone to resist lateral forces, similar to tubular systems. The entire structural weight can be reduced due to the system's significant lateral strength. Therefore, it is the most commonly selected structural system for tall and supertall buildings built in recent years. In this paper, issues regarding the differential shortening effect during construction of the outrigger system and the special joints used to solve these issues will be addressed. Additionally, the characteristics of wind and seismic loads in Korea will be briefly discussed. Lastly, buildings in Korea using an outrigger as their major structural system will be introduced and the structural role of the system will be analyzed.

• International Journal of High-Rise Buildings
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• v.7 no.1
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• pp.47-64
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• 2018

The last decade has seen great design opportunities for tall building construction around the globe. The best designs represent a new generation of skyscrapers that go beyond willful preconceptions of building form and iconography, trying instead to simultaneously address interrelated issues of program space utility, structural efficiency, and environmentally sustainable systems. The resulting identities of these towers are unique because of their search for the intersection of spaces tuned to people's needs, expressive optimized structures, and high performance, site-responsive systems. This paper, through examples of recent SOM towers, both built and unbuilt, will discuss how a design becomes content-driven, how ideas create value, and how the typology of the tall building is advanced through the integration of architecture design and engineering systems.

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