• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.2
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• pp.206-209
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• 2004

A requirement of park management is to transfer the focus from emphasizing the management of public materials to providing services to visitors. Therefore, it has become indispensable to create a scheme in which residents can take management initiative. At this time, we look at Hyogo Prefectural Arimafuji Park, which encourages citizen management participation, and try to understand their system and project contents. For an initial scheme, we identify 4 elements that promoted subjective participation in a council style scheme; 1. to begin activities at the earliest possible time before opening the park, 2. to coordinate with expert(s) who take a neutral position, 3. to have places available where participants can debate on an equal footing, and 4. to plan the project while feeding back actual results.

• Journal of Korean Society of societal Security
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• v.1 no.2
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• pp.79-85
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• 2008

In this study, a new procedure (Unified Dynamic Analysis Method) to evaluate the dynamic responses a bridge under earthquakes is proposed, which is not only considering the bridge motions but also the soil layer motions nearby the bridge footing in order to include the soil-structure interactions. lt is found that the dynamic responses of the whole bridge systems can be properly evaluate from using the proposed UDAM. The properties of the soil layers where the bridge is located can be included into the seismic analysis, and the multi-seismic excitations can also be considered easily.

• Structural Engineering and Mechanics
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• v.41 no.1
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• pp.1-24
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• 2012

A reinforced concrete (RC) framed structure detailed according to non-seismic detailing provisions as per Indian Standard was tested on shake table under dynamic loads. The structure had 3 main storeys and an additional storey to simulate the footing to plinth level. In plan the structure was symmetric with 2 bays in each direction. In order to optimize the information obtained from the tests, tests were planned in three different stages. In the first stage, tests were done with masonry infill panels in one direction to obtain information on the stiffness increase due to addition of infill panels. In second stage, the infills were removed and tests were conducted on the structure without and with tuned liquid dampers (TLD) on the roof of the structure to investigate the effect of TLD on seismic response of the structure. In the third stage, tests were conducted on bare frame structure under biaxial time histories with gradually increasing peak ground acceleration (PGA) till failure. The simulated earthquakes represented low, moderate and severe seismic ground motions. The effects of masonry infill panels on dynamic characteristics of the structure, effectiveness of TLD in reducing the seismic response of structure and the failure patterns of non-seismically detailed structures, are clearly brought out. Details of design and similitude are also discussed.

• Journal of the Korea Concrete Institute
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• v.23 no.5
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• pp.683-692
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• 2011

In piloti-type low-rise RC residential buildings, severe damages have been usually concentrated at piloti stories under the earthquake. In this study, a piloti story was retrofitted by installation of buckling-restrained braces (BRB's) to increase strength and stiffness of piloti story and by application of fiber reinforced polymer (FRP) sheet on columns to avoid the brittle shear and axial failure of columns. To verify this retrofit performance, reversed cyclic lateral load tests were performed on 1:5 scale bare and retrofitted frames. The test results showed that yield strength (43.2 kN) appeared to be significantly larger than design value (30 kN) due to the increase of strength in the compression side, but the stiffness value (11.6 kN/mm) turned out to be approximately one-half of the design value (24.2 kN/mm). The reasons for this difference in stiffness were due to slippage at joint between the frame and the BRB's, displacement and rotation at footing. The energy absorption capacity of the retrofitted frame was 7.5 times larger than that of the bare frame. The change of the number of load cells under the footing from 2 to 1 reduced lateral stiffness from 11.6 kN/mm to 6 kN/mm, which was only three times larger than that of the bare frame (2.1 kN/mm).

• Earthquakes and Structures
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• v.8 no.5
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• pp.1255-1276
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• 2015

The importance of considering soil-structure interaction effect in the analysis and design of RC frame buildings is increasingly recognized but still not penetrated to the grass root level owing to various complexities involved. It is well established fact that the soil-structure interaction effect considerably influence the design of multi-storey buildings subjected to lateral seismic loads. The shear walls are often provided in such buildings to increase the lateral stability to resist seismic lateral loads. In the present work, the linear soil-structure analysis of a G+5 storey RC shear wall building frame resting on isolated column footings and supported by deformable soil is presented. The finite element modelling and analysis is carried out using ANSYS software under normal loads as well as under seismic loads. Various load combinations are considered as per IS-1893 (Part-1):2002. The interaction analysis is carried out with and without shear wall to investigate the effect of inclusion of shear wall on the total and differential settlements in the footings due to deformations in the soil mass. The frame and soil mass both are considered to behave in linear elastic manner. It is observed that the soil-structure interaction effect causes significant total and differential settlements in the footings. Maximum total settlement in footings occurs under vertical loads and inner footings settle more than outer footings creating a saucer shaped settlement profile of the footings. Each combination of seismic loads causes maximum differential settlement in one or more footings. Presence of shear wall decreases pulling/pushing effect of seismic forces on footings resulting in more stability to the structures.

• International Journal of Concrete Structures and Materials
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• v.9 no.3
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• pp.345-367
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• 2015

Past earthquakes have signaled the increased collapse vulnerability of mainshock-damaged bridge piers and urgent need of repair interventions prior to subsequent cascading hazard events, such as aftershocks, triggered by the mainshock (MS). The overarching goal of this study is to quantify the collapse vulnerability of mainshock-damaged substandard RC bridge piers rehabilitated with different repair jackets (FRP, conventional thick steel and hybrid jacket) under aftershock (AS) attacks of various intensities. The efficacy of repair jackets on post-MS resilience of repaired bridges is quantified for a prototype two-span single-column bridge bent with lap-splice deficiency at column-footing interface. Extensive number of incremental dynamic time history analyses on numerical finite element bridge models with deteriorating properties under back-to-back MS-AS sequences were utilized to evaluate the efficacy of different repair jackets on the post-repair behavior of RC bridges subjected to AS attacks. Results indicate the dramatic impact of repair jacket application on post-MS resilience of damaged bridge piers-up to 45.5 % increase of structural collapse capacity-subjected to aftershocks of multiple intensities. Besides, the efficacy of repair jackets is found to be proportionate to the intensity of AS attacks. Moreover, the steel jacket exhibited to be the most vulnerable repair intervention compared to CFRP, irrespective of the seismic sequence (severe MS-severe or moderate AS) or earthquake type (near-fault or far-fault).

• Advances in Computational Design
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• v.2 no.2
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• pp.169-183
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• 2017

This paper shows optimal dimensioning for the corner combined footings to obtain the most economical contact surface on the soil (optimal area), due to an axial load, moment around of the axis "X" and moment around of the axis "Y" applied to each column. The proposed model considers soil real pressure, i.e., the pressure varies linearly. The classical model is developed by trial and error, i.e., a dimension is proposed, and after, using the equation of the biaxial bending is obtained the stress acting on each vertex of the corner combined footing, which must meet the conditions following: 1) Minimum stress should be equal or greater than zero, because the soil is not withstand tensile. 2) Maximum stress must be equal or less than the allowable capacity that can be capable of withstand the soil. Numerical examples are presented to illustrate the validity of the optimization techniques to obtain the minimum area of corner combined footings under an axial load and moments in two directions applied to each column.

• 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.

• Geotechnical Engineering
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• v.2 no.2
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• pp.29-36
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• 1986

In this study, a random vibration technique to anaiyze the vertical vibration of rigid circular footings on sand whose material properties are not previously determind is proposed. Total of 11 circular model footings varing mass ratio and radius are constructed for the vibration experim eat and the elastic half space is represented by compacted sand layer From the random vibration experiments, it is found that the technique suggested in this study gives more accurate prediction of circular footing behavior under vertical vibration than the simplified analog which assumes the subsoils as elastic half space. The predicted resonant frequene iris agree very well with the measured values from the slnusoidal vibration experiments. The ratio of the predicted resonant amplitudes to the measured values vary between 0.5 and 1,35 for the site used for the vibration experiments in this study.

• Geotechnical Engineering
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• v.12 no.4
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• pp.101-114
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• 1996

In this study, the characteristics of bearing capacity and deformation of intermediate soils are investigated through centrifuge tests. The experimental parameters are footing width, initial stress condition of soils and relative loading rate defined relationship of loading rate and permeability of soils. It is examined that loading rate influences on the bearing capacities and deformations. Based on the test results, some problem of existing specification are introduced in the view of related loading rates and load intensities. Especially it is showed that load intensities magnitude rlre reversed in the same settlement ratio(s/B(%)), due to partial drained effect as well as loading rates in undrained con dition based on the excess pore pressure and deformations measured under loading.