Nonlinear Seismic Response of Special-Shaped Column Frame Structures

2010 ◽  
Vol 163-167 ◽  
pp. 1222-1225
Author(s):  
Xiao Bin Han ◽  
Chun Sheng Bao ◽  
Ying Gao ◽  
Jian Min Bian

The spatial analysis model of special-shaped column frame structure is established in ANSYS. The nonlinear dynamic analysis is carried out for the structure by inputting ground motions in one direction. The seismic performance of the structure under rare seismic actions was examined and whether the structure achieved the predetermined seismic aims is evaluated. The results indicates that the structure which under the 8-degree zone designed according to the codes can achieve the predetermined seismic aims under the rarely occurred earthquake actions.

2020 ◽  
Vol 10 (5) ◽  
pp. 1749
Author(s):  
Seung-Ho Choi ◽  
Jin-Ha Hwang ◽  
Sun-Jin Han ◽  
Hyo-Eun Joo ◽  
Hyun-Do Yun ◽  
...  

In recent years, a variety of strengthening methods have been developed to improve the seismic performance of reinforced concrete (RC) frame structures with non-seismic details. In this regard, this study proposes a new type of seismic strengthening method that compresses prefabricated precast concrete (PC) walls from the outside of a building. In order to verify the proposed method, a RC frame structure strengthened with precast walls was fabricated, and cyclic loading tests were performed. The results showed that specimens strengthened using the proposed method exhibited further improvements in strength, stiffness and energy dissipation capacity, compared to RC frame structures with non-seismic details. In addition, a nonlinear analysis method, capable of considering the flexural compression and shear behaviors of the walls, was suggested to analytically evaluate the structural behavior of the frame structures strengthened by the proposed method. Using this, an analysis model for frame structures strengthened with precast walls was proposed. Through the proposed model, the analysis and test results were compared in relation to stiffness, strength, and energy dissipation capacity. Then, the failure mode of the column was evaluated based on the pushover analysis. In addition, this study proposed a simplified analysis model that considered the placement of longitudinal reinforcements in shear walls.


2019 ◽  
Vol 3 (Special Issue on First SACEE'19) ◽  
pp. 181-190
Author(s):  
Yangyang Tang ◽  
Yingmin Li ◽  
Zongming Huang ◽  
Liping Liu ◽  
Yishun Ding ◽  
...  

Frame structures supported by foundations with different elevations (such as a structure on the slope) undergo different ground motions because of the local site effect. Seismic response of the structure under non-uniform excitation of ground motion is different from that under uniform excitation on upper embedding end or lower embedding end. Sites with the same height difference and different soil conditions were set up in this paper to subject them to ground motions related to different positions and the seismic response of structures built on the sites under uniform and non-uniform strong seismic excitation were compared. The results show that the predominant period and amplitude of ground motions on upper embedding end and lower embedding end are different and affected by soil conditions. The extent and law of amplification of shear force, displacement and storey drift of structures under non-uniform excitation differ from those under uniform excitation when soil changes from soft to medium-hard soil. In addition, the position and degree of plastic hinges change under non-uniform excitation compared to uniform excitation. The uniform excitation using the ground motion on the upper embedding end is not always safe for the frame structure supported by foundations at different elevations.


2011 ◽  
Vol 243-249 ◽  
pp. 5152-5156 ◽  
Author(s):  
Jian Tang ◽  
Ping Wen Mao

According to the code and technical regulation, a regular RC frame with specially shaped columns have been designed, which situated at the area of fortification intensity 7(0.15g). Subsequently, the nonlinear dynamic analysis has been carried out for the structure by inputting ground motions in one direction. After summing up the calculation results, this paper have examined seismic performance of the structure under the rare seismic actions and given a primary evaluation on the structure to see if it achieves the predetermined seismic aims. It indicates that the structure designed the codes can achieve the predetermined seismic aims under the rare earthquake.


2014 ◽  
Vol 580-583 ◽  
pp. 1712-1717
Author(s):  
Jian Tang ◽  
Lang Wu

According to the code and technical regulation, a irregular RC frame with specially shaped columns have been designed, which situated at the area of fortification intensity 7. Subsequently, the nonlinear dynamic analysis has been carried out for the structure by inputting ground motions in two directions. After summing up the calculation results, this paper have examined seismic performance of the structure under the rare seismic actions and given a primary evaluation on the structure to see if it achieves the predetermined seismic aims. It indicates that the structure designed the codes can achieve the predetermined seismic aims under the rare earthquake.


2021 ◽  
Vol 83 (4) ◽  
pp. 51-62
Author(s):  
Syed Muhammad Bilal Haider ◽  
Zafarullah Nizamani ◽  
Chun-Chieh Yip ◽  
Jing-Ying Wong

Peninsular Malaysia lies in a low seismic zone, but its building structures had come across the concrete deterioration due to the seismic ground motion originated from far or near field. Notably, most of the building structures in this country are designed based on wind load only. Moreover, current practice to analyze or design a building such as FEMA 368 and EC8 underestimated the effect of repeated excitations. These guidelines only considered single vibrations to evaluate the framed structure. Therefore, the objective of this study was to assess the performance of private educational institute reinforced concrete building with generic 3D two storey frame structure under multiple seismic motions. Structural model was examined under series of earthquake motions which include pre-shock, main shock and aftershock scenario. Total of 7 seismic ground motions were selected to quantify the structural frame model by nonlinear dynamic time history analyses. Pseudo-dynamic ground motions were recorded on shaking table ranging from 0.18 g to 0.82 g were applied onto the building model for assessment. The outcome of this study has identified that the low-rise building model survived at higher PGA values. Moderate damages (0.25 ≤ DI < 0.40) were recorded after passing through multiple ground motions. Moreover, low seismic vibrations with large ground movement had caused ground floor storey act as soft storey. The study concluded that low rise building model had higher tendency to absorb lower to higher ‘g’ values and resist the earthquake loading due to the strength of framed structure.


2012 ◽  
Vol 594-597 ◽  
pp. 886-890 ◽  
Author(s):  
Gan Hong ◽  
Mei Li ◽  
Yi Zhen Yang

Abstract. In the paper, take full account of energy dissipation operating characteristics. Interlayer shear-frame structure for the analysis of the Wilson-Θmethod ELASTOPLASTIC schedule, the design of a nonlinear dynamic time history analysis procedure. On this basis, taking into account the restoring force characteristics of the energy dissipation system, the inflection point in the restoring force model treatment, to avoid a result of the calculation results of distortion due to the iterative error. A frame structure seismic response time history analysis results show that: the framework of the energy dissipation significantly lower than the seismic response of the common framework, and its role in the earthquake when more significant.


Author(s):  
Kensuke Shiomi

Through the 2011 Tohoku Earthquake or the 2016 Kumamoto Earthquake, much larger earthquakes are considered recently in the seismic designs of large steel-frame structures. When structures are exposed by these severe ground motions, partial destructions in the structures, such as damage or fracture of members could happen. Especially, the low cycle fatigue of steel structures because of the repeated load from these long-term ground motions is a serious problem. However, current seismic performance evaluation method based on nonlinear dynamic analysis considers only elastic and plastic deformation of each member, excluding the fracture of members. If this member fracture happens during earthquakes, there is considered to be many effects on the seismic performance, like the changes of the vibration property, the dynamic response and the energy absorbance capacity of structures. Therefore, the fracture of members is preferably taken into account in the seismic performance evaluation for these large earthquakes. This paper proposes the dynamic analysis method for steel-frame structures which can express the member fracture. Dynamic analyses considering and not considering member fracture under the repeated loads supposing the long-term earthquake are conducted to the FEM model of full-scale structure. By comparing each result, the effects of considering member fracture to the seismic performance such as the dynamic response and the energy absorbance capacity are discussed.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Chunyang Liu ◽  
Peng Sun ◽  
Ruofan Shi

This paper proposes two kinds of arrangements of buckling-restrained brace dampers to strengthen soft-first-storey structures locally. Two types of near-fault ground motion, with and without pulse, were selected for a study of the seismic response characteristics of soft-first-storey structures with and without buckling-restrained brace dampers, and the effects of different bracing arrangements on improving the seismic performance of soft-first-storey structures were recognized. The results show that, compared with pulse-free ground motion, near-fault pulsed ground motion results in a more severe seismic response in soft-first-storey frame structures, leading to more serious and rapid destruction of the main structure. Buckling-restrained brace dampers have an obvious energy dissipation effect, play a better role in protecting the main structure, and have good practicality. Compared with structures in which the buckling-restrained brace dampers are arranged only on the bottommost layer, the bottom-four-layer-support structure is more advantageous in terms of seismic performance.


2012 ◽  
Vol 166-169 ◽  
pp. 2209-2215
Author(s):  
Zhi Xin Wang ◽  
Hai Tao Fan ◽  
Huang Juan Zhao

Finite element models of frames with steel-bracings and with concrete filled steel tube struts are built in ETABS. Seismic performance of these models is analyzed with base-shear method, superposition of modal responses method and time history method respectively. The results show that the steel-bracings or concrete filled steel tube struts are efficient to increase the story-stiffness, and the top displacement of the frame structure decreases significantly.


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