scholarly journals INFLUENCE BY SASHIGAMOI JOINT SHAPE AND STRESS STATE AROUND JOINT ON RESTORING FORCE CHARACTERISTICS OF TRADITIONAL WOODEN FRAME

2021 ◽  
Vol 86 (781) ◽  
pp. 437-447
Author(s):  
Xinyan CHEN ◽  
Noriko TAKIYAMA
Keyword(s):  
Stress State ◽  
Restoring Force ◽  
Wooden Frame ◽  
Joint Shape ◽  
Force Characteristics

scholarly journals Seismic Strengthening Effects of Full-Size Reinforced Concrete Frame Retrofitted with Novel Concrete-Filled Tube Modular Frame by Pseudo-Dynamic Testing

2021 ◽  
Vol 11 (11) ◽  
pp. 4898
Author(s):  
Jin-Seon Kim ◽  
Ju-Seong Jung ◽  
Dong-Keun Jung ◽  
Eui-Yong Kim ◽  
Kang-Seok Lee
Keyword(s):  
Dynamic Analysis ◽  
Shear Failure ◽  
Dynamic Testing ◽  
Seismic Intensity ◽  
Seismic Retrofitting ◽  
Restoring Force ◽  
Rc Structures ◽  
Linear Dynamic ◽  
Non Linear ◽  
Force Characteristics

The present study proposes a new seismic retrofitting method using a concrete-filled tube modular frame (CFT-MF) system, a novel technique to overcome and improve the limitations of existing seismic strengthening methods. This CFT-MF seismic retrofitting method makes the most of the advantages of both concrete and steel pipes, thereby significantly improving constructability and increasing integration between the existing structure and the reinforcement joints. This method falls into the category of typical seismic retrofitting methods that focus on increasing strength, in which the required amount of seismic reinforcement can be easily estimated. Therefore, the method provides an easy solution to improving the strength of existing reinforced concrete (RC) structures with non-seismic details that are prone to shear failure. In the present study, a full-size two-story test frame modeled from existing domestic RC structures with non-seismic details was subjected to pseudo-dynamic testing. As a result, the effect of the CFT-MF system, when applied to existing RC structures, was examined and verified, especially as to its seismic retrofitting performance, i.e., restoring force characteristics, stiffness reinforcement, and seismic response control. In addition, based on the pseudo-dynamic testing results, a restoring force characteristics model was proposed to implement non-linear dynamic analysis of a structure retrofitted with the CFT-MF system (i.e., the test frame). Finally, based on the proposed restoring force characteristics, non-linear dynamic analysis was conducted, and the results were compared with those obtained by the pseudo-dynamic tests. The results showed that the RC frame (building) with no retrofitting measures applied underwent shear failure at a seismic intensity of 200 cm/s2, the threshold applied in seismic design in Korea. In contrast, in the frame (building) retrofitted with the CFT-MF system, only minor earthquake damage was observed, and even when the maximum seismic intensity (300 cm/s2) that may occur in Korean was applied, small-scale damage was observed. These results confirmed the validity of the seismic retrofitting method based on the CFT-MF system developed in the present study. The non-linear dynamic analysis and the pseudo-dynamic test showed similar results, with an average deviation of 10% or less in seismic response load and displacement.

Research on Numerical Integration Algorithm for MDOF Pseudo-Dynamic Test

2012 ◽  
Vol 204-208 ◽  
pp. 4820-4826
Author(s):  
Xin Guo ◽  
Li Hua Zhu ◽  
Tian Li Wang
Keyword(s):  
Dynamic Test ◽  
Experimental System ◽  
Test System ◽  
Unconditional Stability ◽  
Comparison Study ◽  
Restoring Force ◽  
Integration Algorithm ◽  
Integration Algorithms ◽  
Simulation Results ◽  
Force Characteristics

This paper focuses on two integration algorithms used for pseudo-dynamic test, explicit Newmark algorithm and implicit alpha-C algorithm. The comparison study between the test and simulation results shows that: the non-uniform distribution of mass, restoring force characteristics and higher frequency vibration modality are simulated more accurately using the alpha-C algorithm than using explicit Newmark algorithm. The alpha-C algorithm also leads to high iterative accuracy and unconditional stability. Replacing the explicit Newmark algorithm in original experimental system by implicit alpha-C algorithm, the MDOF pseudo dynamic test system can be realized successfully.

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