• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.166-173
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• 2013

An aluminum suspension corner module is widely used in high class passenger cars to reduce vehicle weight and improve fuel economy. According to the change of material and suspension type, the evaluation of the static strength and failure mode of the corner module is important. In this study, static strength and failure mode analysis of aluminium multi-link suspension corner module is presented. Static strength test system is designed and static failure mode tests of the corner module are carried out in longitudinal, lateral, and vertical direction. From the resuls of the tests we found that the failure modes are different compare to those of the steel corner module. The static failure modes and load-displacement curves of this study will be used as a guidance in design of a passenger car aluminium multi-link suspension corner module.

• Computers and Concrete
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• v.14 no.2
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• pp.193-209
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• 2014

Cyclic test of the columns is of practical relevance to the performance of compression members during an earthquake loading. The strength, ductility and energy absorption capabilities of reinforced concrete (RC) columns subjected to cyclic loading have been estimated by many researchers. These characteristics are not normally inherent in plain concrete but can be achieved by effectively confining columns through transverse reinforcement. An extensive experimental program, in which performance of four RC columns detailed according to provisions of ACI-318-08 was studied in contrast with that of four columns confined by a new proposed technique. This paper presents performance of columns reinforced by standard detailing and cast with 25 and 32 MPa concrete. The experimentally achieved load-displacement hysteresis and backbone curves of two columns are presented. The two approaches which work in conjunction with Response 2000 have been suggested to draw analytical back bone curves of RC columns. The experimental and analytical backbone curves are found in good agreement. This investigation gives a detail insight of the response of RC columns subjected to cyclic loads during their service life. The suggested analytical procedures will be available to the engineers involved in design to appraise the capacity of RC columns.

• Structural Engineering and Mechanics
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• v.68 no.2
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• pp.193-201
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• 2018

This paper describes an experimental study on the seismic performance of steel reinforced concrete (SRC) T-shaped columns. The lateral loads were applied along the web of the column with different loading histories, such as monotonic loading, mixed loading of variable amplitude cyclic loading and monotonic loading, constant amplitude cyclic loading and variable amplitude cyclic loading. The failure modes, load-displacement curves, characteristic loads and displacements, ductility, strength and stiffness degradations and energy dissipation capacity of the column were analyzed. The effects of loading history on the seismic performance were focused on. The test results show that the specimens behaved differently in the aspects of the failure mode subject to different loading history, although all the failure modes can be summarized as flexural failure. The hysteretic loops of specimens are plump, and minimum values of the failure drift angles and ductility coefficients are 1/24 and 4.64, respectively, which reflect good seismic performance of SRC T-shaped column. With the increasing numbers of loading cycles, the column reveals lower bearing capacity and ductility. The strength and stiffness of the column with variable amplitude cyclic loading degrades more rapidly than that with constant amplitude cyclic loading, and the total cumulative dissipated energy of the former is less.

• Earthquakes and Structures
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• v.14 no.5
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• pp.379-388
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• 2018

This study aims to identify the effect of both longitudinal reinforcement details and damage level on making a decision of repairing pre-damaged bridge columns using basalt fiber reinforced polymer (BFRP) jackets. Two RC bridge columns with improper details of the longitudinal and/or transverse reinforcement were tested under the effect of a constant axial load and increasing lateral cyclic loading. Test results showed that the lap-splice column exhibited an inferior performance where it showed rapid degradation of strength before achieving the theoretical strength and its deformation capacity was limited; however, quick restoration is possible through a suitable rehabilitation technique. On the other hand, expensive repair or even complete replacement could be the decision for the column with the confinement failure mode. After that, a rehabilitation technique using external BFRP jacket was adopted. Performance-based design details guaranteeing the enhancement in the inelastic performance of both damaged columns were addressed and defined. Test results of the repaired columns confirmed that both reparability and the required repairing time of damage structures are dependent on the reinforcement details at the plastic hinge zone. Furthermore, lap-splice of longitudinal reinforcement could be applied as a key design-tool controlling reparability and restorability of RC structures after massive actions.

• Steel and Composite Structures
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• v.28 no.4
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• pp.471-482
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• 2018

The composite reinforced concrete and steel (RCS) structural systems have larger structural lateral stiffness, higher inherent structural damping, and faster construction speed than either traditional reinforcement concrete or steel structures. In this paper, four RCS subassemblies with or without the RC slab designed following a strong column-weak beam philosophy were constructed and tested under reversed-cyclic loading. Parameters including the width of slab and composite effect of the RC slab and beam were explored. The test results showed that all specimens performed in a ductile manner with plastic hinges formed in the beam ends near the column faces. The seismic responses of composite connections are influenced significantly by different width of slabs. Compared with that of the steel beam without the RC slab, it was found that the load carrying capacity of composite connections with the RC slab increased by 30% on average, and strength degradation, energy dissipation also had better performance, while the ductility of that were almost the same. Furthermore, the contribution of connection deformation to the overall specimen displacement was analyzed and compared. It decreased approximately 10% due to the coupling effect in the columns and beams with the RC slab. Based on the test result, some suggestions are presented for the design of composite RCS joints.

• Earthquakes and Structures
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• v.15 no.3
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• pp.275-283
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• 2018

Seismic strengthening is essential for existing bridge piers which are deficient to resist the earthquake. The concrete and CFRP jackets with a bottom-anchoring method are used to strengthen railway bridge piers with low reinforcement ratio. Quasi-static tests of scaled down model piers are performed to evaluate the seismic performance of the original and strengthened bridge pier. The fracture characteristics indicate that the vulnerable position of the railway bridge pier with low reinforcement ratio during earthquake is the pier-footing region and shows flexural failure mode. The force-displacement relationships show that the two strengthening techniques using CFRP and concrete jackets can both provide a significant improvement in load-carrying capacity for railway bridge piers with low reinforcement ratio. It is clear that the bottom-anchoring method by using planted steel bars can guarantee the CFRP and concrete jackets to work jointly with original concrete piers Furthermore, it can be found that the use of CFRP jacket offers advantages over concrete jacket in improving the energy dissipation capacity under lateral cyclic loading. Therefore, the seismic strengthening techniques by the use of CFRP and concrete jackets provide alternative choices for the large numbers of existing railway bridge piers with low reinforcement ratio in China.

• Journal of the Earthquake Engineering Society of Korea
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• v.19 no.5
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• pp.239-246
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• 2015

Reinforced concrete shear walls are effective for resisting lateral loads imposed by wind or earthquakes. Observed damages of the shear wall in recent earthquakes in Chile(2010) and New Zealand(2011) exceeded expectations. Various analytical models have been proposed in order to incorporate such response features in predicting the inelastic response of RC shear walls. However, the model has not been implemented into widely available computer programs, and has not been sufficiently calibrated with and validated against extensive experimental data at both local and global response levels. In this study, reinforced concrete shear walls were modeled with fiber slices, where cross section and reinforcement details of shear walls can be arranged freely. Nonlinear analysis was performed by adding nonlinear shear spring elements that can represent shear deformation. This analysis result will be compared with the existing experiment results. To investigate the nonlinear behavior of reinforced concrete shear walls, reinforced concrete single shear walls with rectangular wall cross section were selected. The analysis results showed that the yield strength of the shear wall was approximately the same value as the experimental results. However, the yielding displacement of the shear wall was still higher in the experiment than the analysis. The analytical model used in this study is available for the analysis of shear wall subjected to high axial forces.

• Interaction and multiscale mechanics
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• v.3 no.4
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• pp.365-372
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• 2010

Station is an important building in high-speed railway, and its vibration and noise may significantly affect the comfort of waiting passengers. A coupling vibration model for train-structure system is established to analyze and evaluate the vibration level of a typical waiting hall under dynamic train load. The motion of a four-axle vehicle with two suspension system is modeled in multi-body dynamics with linear springs and dampers employed. The station is modeled as a whole finite element structure which is 113 m in longitudinal and 163.5 m in lateral, and the stiffness of the station foundation is considered. According to the assumptions that both wheel and rail are rigid bodies and keep contact to each other in vertical direction, and the wheel/rail interaction and displacement coordination in horizontal direction is defined by the simplified Kalker creep theory, the vehicle spatial vibration model has 27 degrees-of-freedom. An overall analysis procedure is made of the train moving through the station, by which the dynamic responses of the train and the station are calculated. According to the comparison between analysis and test results, the actual connection status between different parts of the station is estimated and the vibration level of the waiting hall is evaluated.

• Journal of Korean Society of Steel Construction
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• v.21 no.4
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• pp.343-350
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• 2009

In the present study, a new seismic retrofitting method that employs both a stainless steel wire mesh and a permeable polymer concrete mortar was proposed for reinforced concrete bridge piers with nonseismic design details. For this purpose, a total of six nonseismically designed bridge piers were tested under lateral load reversals. The test results reveal that nonseismically designed piers with lap splices need to be retrofitted to resist earthquake induced forces. In addition, it was proven that the proposed retrofitting method can be useful in improving the strength, stiffness, and energy dissipation capacities of bridge piers designed nonseismically. It is thus expected that the proposed method may provide an improved ductility capacity without sudden softening of strength for bridge piers excursing inelastic displacement range.

• Steel and Composite Structures
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• v.33 no.6
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• pp.767-776
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• 2019

In this article, a simple and robust multi-objective assessment method to control design angles and node positions connected among steel outrigger truss members is proposed to approve both structural safety and economical cost. For given outrigger member layouts, the present method utilizes general-purpose prototypes of outrigger members, having resistance to withstand lateral load effects directly applied to tall buildings, which conform to variable connecting node and design space deposition. Outrigger layouts are set into several initial design conditions of height to width of an arbitrary given design space, i.e., variable design space. And then they are assessed in terms of a proposed multi-objective function optimizing both minimal total displacement and material quantity subjected to design impact factor indicating the importance of objectives. To evaluate the proposed multi-objective function, an analysis model uses a modified Maxwell-Mohr method, and an optimization model is defined by a ground structure assuming arbitrary discrete straight members. It provides a new robust assessment model from a local design point of view, as it may produce specific optimal prototypes of outrigger layouts corresponding to arbitrary height and width ratio of design space. Numerical examples verify the validity and robustness of the present assessment method for controlling prototypes of outrigger truss members considering a multi-objective optimization achieving structural safety and material cost.