• Title/Summary/Keyword: bearing capacity of foundation

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Rule Based System for Selection of Foundation Types of Building Structures (건물의 기초 형식 선정을 위한 규칙 기반 시스템)

  • 김한수;최창근
    • Computational Structural Engineering
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    • v.9 no.1
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    • pp.23-32
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    • 1996
  • A rule based system for foundation design of building structures is developed with CLIPS in this study. The types of foundation and the allowable bearing capacity of supporting soil inferred by the rule based system for selection of foundation type, called SOFTEX, are transferred to a structural design program for building foundation. The allowable bearing capacity is calculated with N values of Standard Penetration Test. The foundation types such as independent spread footing, wall footing, combined footing and mat foundation can be inferred by the foundation merge procedure developed in this study. This procedure is based on the analysis data from the super structure and the estimated bearing capacity. By using this integrated system, structural engineers with less experience in foundation design can design the foundation system for the given superstructure and the site condition with relative ease.

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Experimental Study to Evaluate the Adjacent Construction Effect on the Bearing Capacity and Settlement of Nearby Foundation Structures (근접시공이 기초 구조물의 지지력 및 침하량에 미치는 영향 평가를 위한 실험 연구)

  • Baek, Mun-Kyeong;Lee, Sang Duk;Chang, Ilhan
    • Journal of the Korean Geotechnical Society
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    • v.37 no.8
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    • pp.15-24
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    • 2021
  • Recently, cases for inevitable adjacent construction are increasing due to the limited spaces in urban area. When a new structure is constructed near an existing structure, interference effects induced by the pre-existing structure should be considered. Thus, numbers of studies have been conducted to investigate the effects of adjacent construction, while laboratory scales studies are not well reported. In this study, laboratory scale experiments have been conducted to investigate the bearing capacity and settlement variations with different adjacent construction cases. Results show an optimistic ground bearing capacity increase of the new foundation structure due to the existing foundation structure, while concerns on the increased settlement of the pre-existing structure. Thus, both bearing capacity of the new foundation structure and subsequent settlement of the existing foundation structure have to be considered when assessing the technical applicability of adjacent structure construction on site.

Comparative study on bearing characteristics of pervious concrete piles in silt and clay foundations

  • Cai, Jun;Du, Guangyin;Xia, Han;Sun, Changshen
    • Geomechanics and Engineering
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    • v.27 no.6
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    • pp.595-604
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    • 2021
  • With the advantages of high permeability and strength, pervious concrete piles can be suitable for ground improvement with high water content and low bearing capacity. By comparing the strength and permeability of pervious concrete with different aggregate sizes (3-5 mm and 4-6 mm) and porosities (20%, 25%, 30% and 35%), the recommended aggregate size (3-5 mm) and porosity (30%) can be achieved. The model tests of the pervious concrete piles in soft soil (silt and clay) foundations were conducted to evaluate the bearing characteristics, results show that, for the higher consolidation efficiency of the silty foundation, the bearing capacity of the silty foundation is 16% higher, and the pile-soil stress ratio is smaller. But when it is the ultimate load for the piles, they will penetrate into the underlying layer, which reduces the pile-soil stress ratios. With higher skin friction of the pile in the silty foundation, the pile penetration is smaller, so the decrease of the pile axial force can be less. For the difference in consolidation efficiency, the skin friction of pile in silt is more affected by the effective stress of soil, while the skin friction of pile in clay is more affected by the lateral stress. When the load reaches 4400 N, the skin friction of the pile in the silty foundation is about 35% higher than that of the clay foundation.

Stability Evaluation of Shallow Foundation by Plate Bearing Test (PBT에 의한 직접기초의 안정성 평가)

  • Ki Wan-Seo;Joo Seung-Wan;Kim Sun-Hak
    • The Journal of Engineering Geology
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    • v.15 no.4 s.42
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    • pp.423-433
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    • 2005
  • For the design of spread foundation and the stability evaluation, we compared and analyzed it for theoretical, empirical bearing capacity formulas, and various settlement computation formulas, by conducting the plate bearing test at the site of A and B, which consisted of gneiss weathered soil. In addition, we considered the effective method of stability evaluation by carrying out the plate bearing test carried out on the ground consisted of weathering soil of gneiss. Consequently, it was found out that the allowablebearing capacity by the theoretical formula of Terzaghi was too excessive in comparison with the result of the plate bearing test and the Terzaghi-Peck method, which was used widely domestically in designing the spread foundation. It was more effective for a stable design. As a result of the plate bearing test carried out, on the ground consisted of weathering soil. It was found that reviewing the stability by the bearing capacity calculated with load-settlement curve. It is evaluated in a safer side than the point of view of the settlement.

Load-Settlement Characteristics of Concrete TOP-BASE Foundation on Soft Ground (팽이기초공법(Top-Base Method)의 하중-침하량 분석)

  • Kim, Jae-Young;Jeong, Sang-Seom;Lee, Jae-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.210-221
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    • 2009
  • A new foundation type which is called Top-Base method has been used frequently in engineering practices in Korea. In this study, the settlement behavior of concrete Top-Base foundation on soft ground is investigated since the consolidation settlement of the embedding depth and the effect of footing dimensions are not included in current Korean criterion (2007). To obtain detailed information, the model tests of the Top-Base foundation are performed using the PLAXIS 3D finite element analysis. It is shown that in-situ measurements and finite element analysis of the behavior of foundations indicate that consolidation settlement is reduced up and bearing capacity of the foundation increases up to 50%~100%, compared to the primary non-treated ground. Based on this study, it is found that the Top-Base foundation prevents the lateral deformation of soft ground and reduces its negative dilatancy to the surface settlement, and that the foundation creates rather uniform stress distribution under it to increase its bearing capacity. It is also found that the total settlement of Top-Base foundation was highly dependent on the consolidation settlement and footing configurations.

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A Study on the Bearing Capacity of the Sand Foundation Including the Dense Sand Layer (조밀한 층을 포함하는 사질 지반의 지지력에 관한 연구)

  • Park, Eun Young;Lee, Sang Duk;Kwon, Oh Yeoh;Hu, Chang Tack
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.2
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    • pp.237-242
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    • 1993
  • The bearing capacity of the sand foundation including a thin dense sand layer depends on the stiffiness, thickness and the location of the dense sand layer. In this paper was the influence of the dense sand layer on both the bearing capacity and the failure configuration is studied by means of K.E.M(Kinematic Element Method). K.E.M was implemented to get the excat solution starting from the upper bound of the analysis. The result show that the bearing capacity of the foundation and the failure configuration is greatly influenced by the dense sand layer, when the layer is located not deeper than 3/5 of the foundation width.

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Dispersing Stress under Geogrid-Mattress Foundation (지오그리드 매트리스기호의 전파듣력에 관한 연구)

  • Ju, Jae-U;Jang, Yong-Chae;Park, Jong-Beom
    • Geotechnical Engineering
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    • v.14 no.4
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    • pp.117-128
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    • 1998
  • Solid mattress foundation using geogrid has often been used on soft grounds to increase the bearing capacity, and its effect has received much recognition. Geogrid-mattress system is the method of construction which increases the bearing capacity and the effect of controlling settlement by dispersing load to wider foundation through its stiffness. But ifs mechanism has not been examined exactly yet. considered to be influential factors in the experiments. As a result of the experiments, the characteristic of dispersing stress under mattress foundations was understood and the way of calculating the bearing capacity in designing the mattress foundations was suggested.

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Design of Rigid Sewer Pipe by Bearing Capacity and Settlement (지지력과 침하량을 고려한 강성관용 하수관거 설계)

  • Kim, Seong-Kyum;Oh, Seung-Sik;Lee, Kwan-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.6
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    • pp.137-143
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    • 2020
  • This study proposes an improvement plan for the evaluation of the bearing capacity and settlement of sewer pipe bases for the improvement of design methods for determining pipe breakage. Under the same conditions, the safety of crushed stone foundation was the lowest. Concrete VR pipe and prefabricated plastic foundations were found to be safe at most excavation depths. The bearing capacity of a rigid pipe foundation was determined by the shape of the foundation, soil conditions, and groundwater, irrespective of the type of foundation. As the depth of the excavation increases, the settlement tends to decrease immediately, and as the diameter of the pipe increases, the settlement tends to increase immediately at the same depth. It is thus reasonable to consider the bearing capacity and the instant settlement amount to solve the problems caused by the settlement of a rigid sewer pipe.

Study on application case of reinforce building shallow foundation for soil stabilized materials using circulating resources (순환자원 활용 지반안정재의 건축물 얕은기초 보강 적용사례 연구)

  • Song, Sang-Huwon
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.3
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    • pp.457-462
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    • 2022
  • This study is about the case applied of a shallow foundation reinforcement method for a low/mid-rise building where a relatively small load is applied by using a soil stabilized material that utilizes recycled resources. First, laboratory mixing test was conducted for four mixing ratios in order to derive the optimal mixing ratio in the field. Using the derived optimal mixing ratio, it was applied as a shallow foundation for the building in the field. The field application method used a simple process of compaction by the soil mixedure with the original soil and the soil stabilized material in the field. After field application, a plate bearing test was performed on one original ground and two improved ground to confirm the allowable bearing capacity. As a result of checking the bearing capacity, it was found that sufficient bearing capacity was exhibited.Therefore, it was confirmed that it can be used as a shallow foundation for the building.