Seismic Time-History Analysis of Gravity Dam Based on Nonlinear Finite Element Method

2013 ◽  
Vol 351-352 ◽  
pp. 1047-1051
Author(s):  
He Zhu ◽  
Gang Wang ◽  
Zhen Yue Ma ◽  
Yi Kang Su
Keyword(s):  
Time History ◽  
Nonlinear Finite Element ◽  
Gravity Dam ◽  
Elastic Model ◽  
Nonlinear Finite Element Method ◽  
Initial Stiffness ◽  
Cohesive Model ◽  
Damage Initiation ◽  
History Analysis ◽  
Constitutive Response

A cohesive model (CM) was introduced in this paper. The constitutive response of cohesive behavior depends on a traction-separation description characterized by the initial stiffness, damage initiation threshold, and damage evolution properties.Through the aseismic analysis of a gravity dam, the displacement, stress and anti-sliding safety factor were discussed in the paper, the results were also compared between elastic model (EM) and plastic model (PM). The results shown that the displacement amplitude computed by PM and CM was nearly twice larger than that by EM, and the area of stress concentration became not so obvious. The cohesive model could efficiently simulate the discontinuous structure and the responses of seismic computed by PM and CM were more correspond to actual situation.

scholarly journals Direct displacement-based seismic design of concrete buildings

2000 ◽  
Vol 33 (4) ◽  
pp. 421-444 ◽  
Author(s):  
M.J.N. Priestley ◽  
M.J. Kowalsky
Keyword(s):  
Seismic Design ◽  
Design Procedure ◽  
Time History ◽  
Initial Stiffness ◽  
Concrete Buildings ◽  
History Analysis ◽  
Starting Point ◽  
Displacement Profile ◽  
Displacement Based ◽  
Design Earthquake

A seismic design procedure is developed to enable concrete buildings to be designed to achieve a specified acceptable level of damage under the design earthquake. The acceptable limit is defined as a displacement profile related to limit material strains or code specified drift limits. In this procedure, the elastic properties, including initial stiffness, strength and period, are the end product of the design rather than the starting point. It is shown that the procedure is simple to apply, and results in significant differences from the more conventional force-based procedure. Designs for multi-storey frame and wall buildings are presented, and target displacements are compared with results from inelastic time-history analysis.

scholarly journals Tying Devices to Mitigate Pounding of Adjacent Building Blocks

2020 ◽  
Vol 10 (3) ◽  
pp. 5643-5647
Author(s):  
M. S. Masmoum ◽  
M. S. A. Alama
Keyword(s):  
Seismic Response ◽  
Damage Index ◽  
Time History ◽  
Building Blocks ◽  
Elastic Model ◽  
Expansion Joints ◽  
Linear Elastic ◽  
History Analysis ◽  
Adjacent Building ◽  
Minimum Separation

Adjacent building blocks separated by thermal expansion joints are vulnerable to pounding during earthquakes. The specified Saudi building code minimum separation may be very large and does not necessarily eliminate pounding forces. This research discusses the feasibility of tying the adjacent building blocks with simple devices to mitigate structural pounding when separated by thermal joints. Six and twelve-story moment resistance frames of intermediate ductility were designed for seismic loads of moderate risk. The seismic response was studied for frames with variable separation distances in three cases related to thermal joint, code minimum separation, required separation to eliminate pounding force, and in a fourth case in which the tying device was used along with thermal separation. A linear elastic model was used to model the assigned gap links between the adjacent building blocks. The tying device was modeled with a tension-only hook element. Four normalized earthquake records were used with inelastic-time history analysis to assess the seismic response of the adjacent building blocks. The proposed tying devices reduced successfully the pounding forces by 40% to 60% for adjacent building blocks with installed thermal separations. Building damage as observed from damage index and the hysteretic response was not influenced by the pounding force, indicating that the tying may be used on existing buildings with thermal separation as a partial mitigation technique to reduce the pounding hazard in such cases. Further improvement on the tying device will increase the mitigation of the pounding hazard.

Parameters Analysis of Re-Centring SMA Damper Based on SAP2000

2012 ◽  
Vol 166-169 ◽  
pp. 219-225 ◽  
Author(s):  
Yu Hong Ling ◽  
Hong Hua Ling
Keyword(s):  
Time History ◽  
Force Model ◽  
Initial Stiffness ◽  
Restoring Force ◽  
Finite Element Software ◽  
History Analysis ◽  
Yield Displacement ◽  
Value Range ◽  
Structural Layer ◽  
Energy Components

According to the working mechanism of re-centring SMA damper, restoring force model is established. Based on the mechanical model, the re-centring SMA damper is modeled in finite element software SAP2000 by adding Multi-Linear element and Plastic (Wen) element. Time-history analysis method under different ground motion is used to analyze control parameters of re-centring SMA damper. The influence on damping effect and ability to re-centring of damper of several factors such as the ratio SR of initial stiffness of energy components and stiffness of corresponding structural layer, the ratio β of yield displacement of energy components and yield displacement of corresponding structural layer, the ratio α of the second stiffness and initial stiffness of energy components, the ratio Q of initial restoring force of re-centring group and yield force of corresponding structural layer, and the ratio λ of the second stiffness and initial stiffness of re-centring group were studied. Their reasonable numerical value range are obtained by numerical calculation, the reasonable ranges for SR, β, α, Q and λ are found to be 2~3, 0~0.05, 0~0.1, 0.05~0.10 and 0.05~0.15 respectively.

PERILAKU STRUKTUR BAJA TIPE MRF DENGAN BEBAN LATERAL BERDASARKAN SNI 1726-2012 DAN METODE PERFORMANCE BASED PLASTIC DESIGN (PBPD)

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Nidiasari Jati Sunaryati Eem Ikhsan
Keyword(s):  
Pushover Analysis ◽  
Time History ◽  
Time History Analysis ◽  
Plastic Design ◽  
History Analysis ◽  
Non Linear ◽  
Static Pushover Analysis

Struktur rangka baja pemikul momen merupakan jenis struktur baja tahan gempa yang populer digunakan. Daktilitas struktur yang tinggi merupakan salah satu keunggulan struktur ini, sehingga mampu menahan deformasi inelastik yang besar. Dalam desain, penggunaan metode desain elastis berupa evaluasi non-linear static (Pushover analysis) maupun evaluasi non-linear analisis (Time History Analysis) masih digunakan sebagai dasar perencanaan meskipun perilaku struktur sebenarnya saat kondisi inelastik tidak dapat digambarkan dengan baik. Metode Performance-Based Plastic Design (PBPD) berkembang untuk melihat perilaku struktur sebenarnya dengan cara menetapkan terlebih dahulu simpangan dan mekanisme leleh struktur sehingga gaya geser dasar yang digunakan adalah sama dengan usaha yang dibutuhkan untuk mendorong struktur hingga tercapai simpangan yang telah direncanakan. Studi dilakukan terhadap struktur baja 5 lantai yang diberi beban gempa berdasarkan SNI 1726, 2012 dan berdasarkan metode PBPD. Hasil analisa menunjukkan bahwa struktur yang diberi gaya gempa berdasarkan metode PBPD mencapai simpangan maksimum sesuai simpangan rencana dan kinerja struktur yang dihasilkan lebih baik .

Response Law and Influencing Factors of the Soil under Action of Pile Driving Vibration Based on Midas/GTS

2013 ◽  
Vol 353-356 ◽  
pp. 979-983
Author(s):  
Dong Zhang ◽  
Jing Bo Su ◽  
Hui De Zhao ◽  
Hai Yan Wang
Keyword(s):  
Damping Ratio ◽  
Large Diameter ◽  
Time History ◽  
Pile Driving ◽  
Analysis Model ◽  
Vibration Load ◽  
History Analysis ◽  
Study Results ◽  
Propagation Law ◽  
Dynamic Time

Due to the upgrade and reconstruct of a high-piled wharf, the piling construction may cause the damage of the large diameter underground pipe of a power plant nearby. For this problem, a dynamic time-history analysis model was established using MIDAS/GTS program. Based on the analysis of the pile driving vibration and its propagation law, some parameters, such as the modulus of the soil, the Poissons ratio of soil, the action time of vibration load and the damping ratio of the soil that may have an effect on the response law of the soil, were studied. The study results not only serve as an important inference to the construction of this case, but also accumulate experience and data for other similar engineering practices.

scholarly journals Record-to-record variability and code-compatible seismic safety-checking with limited number of records

2021 ◽  
Author(s):  
Fatemeh Jalayer ◽  
Hossein Ebrahimian ◽  
Andrea Miano
Keyword(s):  
Seismic Hazard ◽  
Linear Time ◽  
Time History ◽  
Time History Analysis ◽  
Seismic Safety ◽  
Hazard Curve ◽  
History Analysis ◽  
Non Linear ◽  
Seismic Hazard Curve ◽  
Cloud Analysis

AbstractThe Italian code requires spectrum compatibility with mean spectrum for a suite of accelerograms selected for time-history analysis. Although these requirements define minimum acceptability criteria, it is likely that code-based non-linear dynamic analysis is going to be done based on limited number of records. Performance-based safety-checking provides formal basis for addressing the record-to-record variability and the epistemic uncertainties due to limited number of records and in the estimation of the seismic hazard curve. “Cloud Analysis” is a non-linear time-history analysis procedure that employs the structural response to un-scaled ground motion records and can be directly implemented in performance-based safety-checking. This paper interprets the code-based provisions in a performance-based key and applies further restrictions to spectrum-compatible record selection aiming to implement Cloud Analysis. It is shown that, by multiplying a closed-form coefficient, code-based safety ratio could be transformed into simplified performance-based safety ratio. It is shown that, as a proof of concept, if the partial safety factors in the code are set to unity, this coefficient is going to be on average slightly larger than unity. The paper provides the basis for propagating the epistemic uncertainties due to limited sample size and in the seismic hazard curve to the performance-based safety ratio both in a rigorous and simplified manner. If epistemic uncertainties are considered, the average code-based safety checking could end up being unconservative with respect to performance-based procedures when the number of records is small. However, it is shown that performance-based safety checking is possible with no extra structural analyses.

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