• Computers and Concrete
• /
• v.16 no.5
• /
• pp.703-722
• /
• 2015

This study investigates the performance of advanced hollow reinforced concrete (RC) bridge column sections with triangular reinforcement details. Hollow column sections are based on economic considerations of cost savings associated with reduced material and design moments, as against increased construction complexity, and hence increased labor costs. The proposed innovative reinforcement details are economically feasible and rational, and facilitate shorter construction periods. We tested a model of advanced hollow column sections under quasi-static monotonic loading. The results showed that the proposed triangular reinforcement details were equal to the existing reinforcement details, in terms of the required performance. We used a computer program, Reinforced Concrete Analysis in Higher Evaluation System Technology (RCAHEST), for analysis of the RC structures; and adopted a modified lateral confining effect model for the advanced hollow bridge column sections. Our study documents the testing of hollow RC bridge column sections with innovative reinforcement details, and presents conclusions based on the experimental and analytical findings. Additional full-scale experimental research is needed to refine and confirm the design details, especially for the actual detailing employed in the field.

• Coupled systems mechanics
• /
• v.8 no.2
• /
• pp.185-197
• /
• 2019

Considering the increasing use of tubular profiles in civil construction, this paper highlights the study on the behavior of welded connections between square hollow section column and I-beam, with emphasis on the assessment of the joint stiffness. Firstly, a theoretical analysis of the welded joints has been done focusing on prescriptions of the technical literature for the types of geometries mentioned. Then, a numerical analysis of the proposed joints were performed by the finite element method (FEM) with the software ANSYS 16.0. In this study, two models were evaluated for different parameters, such as the thickness of the cross section of the column and the sizes of cross section of the beams. The first model describes a connection in which one beam is connected to the column in a unique bending plane, while the second model describes a connection of two beams to the column in two bending planes. From the numerical results, the bending moment-rotation ($M-{\varphi}$) curve was plotted in order to determine the resistant bending moment and classify each connection according to its rotational capacity. Furthermore, an equation was established with the aim of estimating the rotational stiffness of welded I beam-to-RHS column connections, which can be used during the structure design. The results show that most of the connections are semi-rigid, highlighting the importance of considering the stiffness of the connections in the structure design.

• Structural Engineering and Mechanics
• /
• v.77 no.3
• /
• pp.383-394
• /
• 2021

Column foot in traditional Chinese timber structures may be subjected to be uplifted due to the lateral load and subsequently reset under the vertical loads. The residual moment of the rocking column foot is the most important parameter representing the mechanical behaviors of column foot, and the simplification of joints is the basis of structural analysis of whole structure. The complicated mechanical behaviors of joint and the modeling of the column foot joint has been undertaken historically based on the experiments and numerical simulation. On the condition of limited application range of those models, a lack of simplified model to represent the mechanical behaviors of joint deserves attentions. There is a great need to undertake theoretical studies to derive the residual moment and make better simplified model of the joint. This paper proposes the residual moment and equivalent simplified model of the rotational stiffness for column foot joint. And, the timber frame is established based on the simplified model, which is verified by solid finite element model. Results show that a mutual agreement on the mechanical behaviors of the timber frame is obtained between the simplified model and the solid finite element model. This study can serve as the references of the structural analysis for the traditional timber structures.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.26 no.2
• /
• pp.83-93
• /
• 2022

In this study, to verify the structural performance of the Composite Joint System (CJS) hybrid structural model, a cyclic load test was performed and evaluated and verified through the test. To verify the structural performance of the CJS hybrid structural systems' joint and evaluate the seismic performance, four three-dimensional real-size specimens were developed with three internal beam-column specimens and one external beam-column specimen. The three interior column specimens were classified by different methods of joining the upper column and lower column, and the same bonding method as the primary specimen was used for the exterior column. The structural performances in terms of drift, strength, and energy dissipation capacity were analyzed and compared based on the experimental results. From the displacement-based loading experiment, all specimens showed a lateral drift of 4.0% without any significant strength drop and stable energy dissipation capacity.

• Journal of Korean Association for Spatial Structures
• /
• v.24 no.1
• /
• pp.81-88
• /
• 2024

The purpose of this study is to experimentally analyze the seismic performance of beam-column specimens with vertical irregular, which were reinforced with RHS (Replaceable steel haunch system). a steel haunch system. To evaluate the seismic performance of the RHS, three specimens were manufactured and subjected to cycle loading tests. Retrofitted specimens have different beam-upper column stiffness ratio as a variable. The stiffness ratio of beam-upper column were considered to be 1.2 and 0.84. As a result of the test, the specimen reinforced with RHS showed improved maximum load and effective stiffness, and energy dissipation capacity compared to the non-retrofitted specimen with same beam-upper column stiffness ratio. The specimen with 0.84 beam-upper column stiffness ratio showed improved performance than the specimen with 12.

• Earthquakes and Structures
• /
• v.27 no.4
• /
• pp.251-262
• /
• 2024

To improve the seismic behavior of composite column with high strength concrete-filled steel tubular in bridge engineering, four column specimens, including one specimen with vertical prestressing force and three specimens with tri-directional prestressing force, were conducted under low cyclic loading. Test parameters including axial compression ratio, degree of vertical prestressing and existence of prestressed steel strips were emphatically analyzed. Experimental results revealed that applying tri-directional prestressing force to column with high strength concrete-filled steel tubular produced more beneficial behavior in terms of ductility, energy-dissipation and self-centering capacity over that of specimens only with vertical prestress. Moreover, ultimate bearing capacity of composite column was improved with increase of degree of vertical prestress and external axial force, while ductility would be reduced. External axial force showed slight influence on the self-centering behavior. Finally, a calculation equation for predicting the shear capacity of the tri-directional prestressed composite column was proposed and the accuracy of the calculated results validated by experimental data.

• Journal of the Korean Applied Science and Technology
• /
• v.33 no.3
• /
• pp.459-465
• /
• 2016

This study investigated reusability of costly guard column by ultrasonic. It also investigated various effects that affect to guard column generation by ultrasonic. When investigated 30 KHz of frequency, area of ascorbic acid is 73.0% compared to unused guard column. As a result of investigation of effect of pH, guard column by ultrasonic is effective at alkali area. As a result of investigation of solvent effect, when ethanol is used, generation rate is 81.9% as of peak area compared to the case of analysis in un used column. From the result, it indicates that regenerated guard by ultrasonic is reusable.

• Journal of the Korea Institute of Building Construction
• /
• v.5 no.4 s.18
• /
• pp.145-152
• /
• 2005

Long-term axial shortening of the vertical elements of tail buildings results in differential movements between two elements and may lead to the additional moments of connection beam and slab elements, and other secondary effects, such as cracks of partitions or curtain walls. Accurate prediction of time-dependent column shortening is essential for tall buildings from both strength and serviceability aspects. The compensation method is different from reinforced concrete and SRC(Steel Reinforced Concrete) members. The SRC columns are usually compensated according to total differential shortening between two vertical elements. In this study, column shortenings of 37-story W building under construction are predicted and compensated. The SRC column shortenings are compared with the actual column shortening by field measurement and the column shortenings are reanalysed and recompensated.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.30-33
• /
• 2006

The purpose of this research is to study the seismic behavior of interior column-slab connections with different column aspect ratio, when subjected to combined gravity and cyclic lateral loading. The control specimen had square column, while the other specimens had rectangular column with aspect ratio of 0.5 and 2.0. From the test results, all of the specimens sustain lateral drifts as high as 4% with no more than a 20% decrease in peak lateral load capacity. And it appears that KBC Code(2005) procedure may be unconservative for connections with different column aspect ratio.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.146-149
• /
• 2006

In many previous studies, a prestressed concrete column has a larger flexural strength, shear strength and restoring force than a RC column. Recently, a precast prestressed concrete column is rising up a very rational column structure in that a economic aspect. In a precast prestressed concrete column, it makes in a factory. So, it needs a small construction site and acquires a higher durability than a cast in place concrete column. Seven precast concrete columns were tested under a constant axial load and a cyclically reversed horizontal load to investigate the performance. It is designed with a hollow section and consisted of 4 segments. The main variables of the test were a amount of prestressed, a type of joints and a boding type of strands. The test results show that the performance of a precast prestressed concrete column; failure mode, maximum load, energy dissipation and stiffness degradation.