• Earthquakes and Structures
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• v.1 no.2
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• pp.177-195
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• 2010

This paper presents an appraisal of four nonlinear static procedures (CSM, N2, MPA and ACSM) employed in seismic assessment of plan-irregular buildings. It uses a three storey reinforced concrete plan-irregular frame building exemplifying typical older constructions of the Mediterranean region in the early 1970s that was tested in full-scale under bi-directional pseudo-dynamic loading condition at JRC, Ispra. The adequacy and efficiency of the simplified analytical modelling assumptions adopted were verified. In addition, the appropriate variants of code-prescribed NSPs (CSM and N2) to be considered for subsequent evaluation were established. Subsequent parametric studies revealed that all such NSPs predicted reasonably well both global and local responses, having the benchmark values been determined through nonlinear dynamic analyses using a suit of seven ground motions applied with four different orientations. The ACSM, however, predicted responses that matched slightly better the median dynamic results.

• Structural Engineering and Mechanics
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• v.57 no.5
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• pp.861-876
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• 2016

The determination of the critical buckling load of multistory structures is important since this load is used in second order analysis. It is more realistic to determine the critical buckling load of multistory structures using the whole system instead of independent elements. In this study, a method is proposed for designating the system critical buckling load of torsion-free structures of which the load-bearing system consists of frames and shear walls. In the method presented, the multistory structure is modeled in accordance with the continuous system calculation model and the differential equation governing the stability case is solved using the differential transform method (DTM). At the end of the study, an example problem is solved to show the conformity of the presented method with the finite elements method (FEM).

• Earthquakes and Structures
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• v.10 no.3
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• pp.629-643
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• 2016

Among all the natural disasters, earthquakes are the most destructive calamities since they cause a plenty of injuries and economic losses leaving behind a series of signs of panic. The present study highlights the moment-curvature relationships for the structural elements such as beam and column elements and Non-Linear Static Pushover Analysis of RC frame structures since it is a very simplified procedure of non-linear static analysis. The highly popular model namely Mander's model and Kent and Park model are considered and then, seismic risk evaluation of RC building has been conducted using SAP 2000 version 17 treating uncertainty in strength as a parameter. From the obtained capacity and demand curves, the performance level of the structure has been defined. The seismic fragility curves were developed for the variations in the material strength and damage state threshold are calculated. Also the comparison of experimental and analytical results has been conducted.

• Steel and Composite Structures
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• v.10 no.2
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• pp.109-128
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• 2010

The expediency of using tubular composite steel and concrete columns of annular cross-sections in construction is discussed. The new type space framework with tubular composite columns of multi-storey buildings and its rigid beam-column joints are demonstrated. The features of interaction between the circular steel tube and spun concrete stress-strain states during the concentrical and eccentrical loading of tubular composite members are considered. The modeling of the bearing capacity of beam-columns of composite annular cross-sections is based on the concepts of bending with a concentrical force and compression with a bending moment. The comparison of modeling results for the composite cross-sections of beam-columns is analysed. The expediency of using these concepts for the limit state verification of beam-columns in the methods of the partial safety factors design (PSFD) legitimated in Europe and the load and resistance factors design (LRFD) used in other countries is presented and illustrated by a numerical example.

• International Journal of High-Rise Buildings
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• v.10 no.3
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• pp.173-178
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• 2021

In this paper we introduce Shinagawa HEART, located in Shinagawa district, Tokyo. It is a mixed-use building with residences on the upper floors, offices on the lower floors, and commercial uses on the first and second floors, and is intended to meet the various needs of a building on the border between residential and commercial areas. The upper floors of the building are made of reinforced concrete, while the middle and lower floors are made of steel with CFT columns. First, an overview of the structural plan of the building is presented. Next, the adoption of the middle layer seismic isolation and the switch between the lower steel structure and the upper reinforced concrete structure, which are the features of this building, are explained. Finally, the construction method adopted to achieve the design performance is explained.

• International Journal of High-Rise Buildings
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• v.10 no.3
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• pp.193-201
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• 2021

Cheongna City Tower is a 448-meter-high rise observatory tower with 8.7:1 aspect ratio located at central lake park in Incheon Cheongna international city. The tower is a crystal shaped image and it turns invisible when the façade is activated. The tower was planned to be hexagonal 30-story building with two basements which are composed of mega frame structure using mega column and mega brace. In order to minimize the wind effect, the blow-through area was installed so that the wind can pass through. This observatory tower is an unprecedented project since the whole building is covered by façade for invisibility effect.

• International Journal of High-Rise Buildings
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• v.10 no.3
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• pp.211-218
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• 2021

A new type of earthquake resilient reinforced concrete (RC) shear wall structure, installed with replaceable coupling beams and replaceable corner components at the bottom of wall piers, is proposed in this study. At first, the mechanical behavior of replaceable components, such as combined dampers and replaceable corner component, is studied by cyclic loading tests on them. Then, cycling loading tests are conducted on one conventional coupled shear wall and one new type of coupled shear wall with replaceable components. The test results indicate that the damage of the new type of coupled shear wall concentrates on replaceable components and the left parts are well protected. Finally, a case study is introduced. The responses of one conventional frame-tube structure and one new type of structure installed with replaceable components under the wind and the earthquake are compared, which verify that the performance of new type of structure is much better than the conventional structure.

• International journal of steel structures
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• v.18 no.4
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• pp.1470-1481
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• 2018

Building-level response to post-earthquake fire hazards in steel buildings has been assessed using primarily two-dimensional analyses of the lateral force resisting system. This approach may not adequately consider potential vulnerabilities in the gravity framing system. For this reason, three-dimensional (3D) finite element models of a 10-story case study building with perimeter moment resisting frames were developed to analyze post-earthquake fire events and better understand building response. Earthquakes are simulated using ground motion time histories, while Eurocode parametric time-temperature curves are used to represent compartment fires. Incremental dynamic analysis and incremental fire analysis procedures capture a range of hazard intensities. Findings show that the structural response due to earthquake and fire hazards are somewhat decoupled from one another. Regardless of the level of plastic hinging present in the moment framing system due to a seismic event, gravity column failure is the initiating failure mode in a fire event.

• International Journal of High-Rise Buildings
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• v.10 no.3
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• pp.219-227
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• 2021

This building is a forty-eight story, 170 meters high multiple dwelling house with Dual Frame System (DFS), a coupled vibration system connecting two independent structures with hydraulic dampers. Generation of large deformation between two structures during earthquakes contributes to make the hydraulic dampers effective. To improve the aseismic performance more, this building adopts DFS hybrid system that consists of DFS and base isolation system. About typical floors, columns and beams are constructed with LRV precast concrete method that shorten the construction period greatly by integrating column-beam joints in column members.

• International Journal of High-Rise Buildings
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• v.11 no.3
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• pp.189-196
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• 2022

The practical difficulties of construction will impose many restrictions on the structural design, and the construction method can also provide unexpected ideas for solving design problems. Through the discussion of three issues closely related to construction in the structural design of Wuhan Center, this paper illustrates the importance of in-depth consideration of the construction situations in the structural design stage. The topics of "Connection between Embedded Steel Plates in Steel Plate Composite Shear Wall" and "Connection Joint between Outrigger Truss and Core Wall" are about how to facilitate on-site construction by simplifying and optimizing detail design. The topic of "Adjusting Internal Force Distribution by Optimizing Construction Sequence" is about how to make the construction process a tool for structural design.