Ductility Characteristics of Partially Restrained Beam-To-Column Composite Connections in Concrete Filled Square Tubes

2008 ◽  
Vol 11 (5) ◽  
pp. 565-575 ◽  
Author(s):  
Suhee Park ◽  
Sungmo Choi ◽  
Youngwook Park ◽  
Yosuk Kim ◽  
Jinho Kim

This paper presents the development of an improved detail in partially restrained beam-to-column composite connections in concrete filled square tubes and the evaluation of its structural characteristics and behaviour under monotonic and cyclic loading. Studies for the bolted seat-angle connections of existing partially restrained composite connection (PR-CC) details have been conducted mostly on shallow beam-to-column connections. In case of deep beam-to-column connections, the fabrication becomes complicated because the sizes of the seat-angles are larger than the connections, and the number of bolts and welding length are increased. This study suggests a new detail of PR-CC which can be applied to concrete-filled tubular structures incorporating the effect of composite slabs and the performance for construction work. A welded bottom beam flange connection is proposed to enhance the capacity of the bottom of the connection and to improve ductility and fabrication. In addition, a reduced beam section (RBS) is adapted for the bottom beam flange to examine its effect on ductility. A seat-angle connection with penetrating bolts is also suggested and compared with the welded bottom beam flange connection. Both monotonic and cyclic loading tests are conducted on the five full scale specimens to compare and evaluate their ductility characteristics.

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3920
Author(s):  
Jaehoon Bae ◽  
Chang-Hwan Lee ◽  
Minjae Park ◽  
Robel Wondimu Alemayehu ◽  
Jaeho Ryu ◽  
...  

Conventional slit dampers are widely used for the purpose of seismic retrofitting, however, the structure of these dampers is susceptible to fractures, due to stress concentration at the ends of the strips in the event of large earthquakes. To address this issue, a novel radius-cut coke-shaped strip damper featuring improved ductility is proposed herein. This damper was developed based on the moment distribution over the strip when both its ends were constrained. The height-to-width ratio of the strip was increased to induce bending rather than shear deformation, and the reduced beam section method was employed. A radius-cut section was used to intentionally focus the stress to induce the plastic hinge. This reduced the fracture fragility of the specimen, resulting in an increased inelastic deformation capacity. Cyclic loading tests were conducted to verify damping performance against earthquakes. Experiments and finite element analyses proved that the coke-shaped damper exhibits improved ductility. The final fracture occurred in the radius-cut section after sufficient energy dissipation during cyclic loading. The results also indicated further improvements in strength due to the membrane effect under cyclic loading, caused by the tensile resistance of the strip due to its constrained ends.


2019 ◽  
Vol 25 (60) ◽  
pp. 655-659
Author(s):  
Shuzo HIROISHI ◽  
Akira OKADA ◽  
Naoya MIYASATO ◽  
Noburu NAKAMURA ◽  
Kenichi MAMURO ◽  
...  

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Qingguang He ◽  
Yanxia Bai ◽  
Weike Wu ◽  
Yongfeng Du

A novel assembled self-centering variable friction (SCVF) brace is proposed which is composed of an energy dissipation system, a self-centering system, and a set of force transmission devices. The hysteretic characteristics and energy dissipation of the SCVF brace with various parameters from low-cyclic loading tests are presented. A finite element model was constructed and tested under simulated examination for comparative analysis. The results indicate that the brace shows an atypical flag-type hysteresis curve. The SCVF brace showed its stable self-centering ability and dissipation energy capacity within the permitted axial deformation under different spring and friction plates. A larger deflection of the friction plate will make the variable friction of this SCVF brace more obvious. A higher friction coefficient will make the energy dissipation capacity of the SCVF brace stronger, but the actual friction coefficient will be lower than the design value after repeated cycles. The results of the fatigue tests showed that the energy dissipation system formed by the ceramic fiber friction blocks and the friction steel plates in the SCVF brace has a certain stability. The finite element simulation results are essentially consistent with the obtained test results, which is conducive to the use of finite element software for calculation and structural analysis in actual engineering design.


2018 ◽  
Vol 91 (1) ◽  
pp. 136-150 ◽  
Author(s):  
Mei Sze Loo ◽  
Jean Benoît Le Cam ◽  
Andri Andriyana ◽  
Eric Robin

ABSTRACT Palm biodiesel is deemed a promising future fuel substitute for conventional diesel fuel. In line with this perspective, necessary changes in the existing diesel engine system are expected in order to address the issue of material compatibility. One typical degradation observed in rubber components exposed to aggressive solvent such as palm biodiesel during the service is swelling. Thus, the investigation of the effect of swelling on the mechanical response under cyclic loading is prerequisite for durability analysis of such components. In this study, filled and unfilled swollen nitrile rubbers are immersed in conventional diesel and palm biodiesel baths until a 5% swelling level is achieved. Both dry and swollen rubbers are subjected to uniaxial cyclic loading tests. The analysis of the mechanical responses has shown that swelling decreases inelastic effects such as hysteresis, stress softening, and permanent set. For both dry and swollen rubbers, fillers are found to have significant effects in the inelastic responses, whereas the effects of solvent and loading rate are comparable.


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