scholarly journals Probabilistic considerations for the design of deep foundations against excessive differential settlement

2016 ◽  
Vol 53 (7) ◽  
pp. 1167-1175 ◽  
Author(s):  
Farzaneh Naghibi ◽  
Gordon A. Fenton ◽  
D.V. Griffiths
Keyword(s):  
Differential Settlement ◽  
Deep Foundations ◽  
Foundation Settlement ◽  
Design Practice ◽  
Probabilistic Theory ◽  
Small Probability ◽  
Limit States ◽  
Foundation Design ◽  
Total Settlement ◽  
Acceptable Probability

Current foundation design practice for serviceability limit states involves proportioning the foundation to achieve an acceptably small probability that the foundation settlement exceeds some target maximum total settlement. However, it is usually differential settlement that leads to problems in the supported structure. The design question, then, is how should the target maximum total settlement of an individual foundation be selected so that differential settlement is not excessive? Evidently, if the target maximum total settlement is increased, the differential settlement between foundations will also tend to increase, so that there is a relationship between the two, although not necessarily a simple one. This paper investigates how the target maximum total settlement specified in the design of an individual foundation relates to the distribution of the differential settlement between two identical foundation elements, as a function of the ground statistics and the distance between the two foundations. A probabilistic theory is developed, and validated by simulation, which is used to prescribe target maximum settlements employed in the design process to avoid excessive differential settlements to some acceptable probability.

How distribution characteristics of a soil property affect probabilistic foundation settlement — from the aspect of the first four statistical moments

2020 ◽  
Vol 57 (4) ◽  
pp. 595-607 ◽  
Author(s):  
Yongxin Wu ◽  
Yufeng Gao ◽  
Limin Zhang ◽  
Jun Yang
Keyword(s):  
Elastic Modulus ◽  
Probability Model ◽  
Differential Settlement ◽  
Shallow Foundation ◽  
Statistical Moments ◽  
Foundation Settlement ◽  
Spectral Representation Method ◽  
Total Differential ◽  
Total Settlement ◽  
Representation Method

The effects of the first four statistical moments defining the statistical characteristic of elastic modulus on the probabilistic foundation settlement are investigated in this study. By combining the Hermite probability model and spectral representation method, a method to simulate nonGaussian homogenous fields based on the first four statistical moments is proposed. Linear elastic finite element models are employed to study the total settlement and the differential settlement of a shallow foundation. Probabilistic measurements of total–differential settlement obtained by the Monte Carlo simulations are presented. For the cases considered, the effects of skewness and kurtosis defining the probabilistic characteristic of elastic modulus on the total–differential settlement of a probabilistic foundation are illustrated. The computed results show that the value of skewness has a more significant effect on the probabilistic foundation settlement than kurtosis, and the case with the smallest skewness is observed as the most critical one.

Impact of Double-O-Tube Shield Tunnel Construction on Grillage Beams Foundation Frame Building

2011 ◽  
Vol 71-78 ◽  
pp. 32-36 ◽  
Author(s):  
Xin Jiang Wei ◽  
Jie Hong ◽  
Gang Wei
Keyword(s):  
Principal Stress ◽  
Differential Settlement ◽  
Shield Tunnel ◽  
Tunnel Construction ◽  
Foundation Settlement ◽  
Ground Settlement ◽  
Shield Tunneling ◽  
Frame Building ◽  
Shield Machine ◽  
The Impact

Considering the interaction of building-soil-tunnel, the grillage beams foundation frame building vertical crossed by Double-O-Tube (DOT) shield tunnel was simulated by 3D MIDAS/ GTS software, and the impact of construction on the building was analyzed. The results show that: the ground settlement trough caused by DOT shield tunnel can be fitted by peck formula; during the passage of the shield tunneling through the building, the settlement of the building increased and settlement trough was wilder; the settlement was stable and had a little rebound when shield machine already passed the building; with the increase of driving distance, the first principal stress P1 increased and then was stable; with the increase of L, the shape of foundation settlement curve changed, and the maximum differential settlement between columns increased but was small.

Stress Calculation of a Spherical Tank on Settled Ground Based on FEM

2013 ◽  
Vol 331 ◽  
pp. 110-113
Author(s):  
Hong Li Gao ◽  
Wei Jun Li ◽  
Zhi Hai Li
Keyword(s):  
Stress Distribution ◽  
Maximum Stress ◽  
Differential Settlement ◽  
Foundation Settlement ◽  
Stress Calculation ◽  
Spherical Tank

In this paper, a model of a LGP spherical tank supported by 8 equator tangent-type supporting on settled ground was built.The stress on the shell,on the pillars and on the connection of pillars with shell were calculated,the stress distribution on shell,pillars and the connection of pillars with shell were obtained, the influence of foundation settlement to the stress of shell and pillars were studied. The results showed that the differential settlement produced a less affect on the shell,but a greater impact on the pillars. The maximum stress arose at the connection between pillars and shell ,there is a big stress area in the connectors area.

Eighteenth Canadian Geotechnical Colloquium: Limit States Design For Foundations. Part I. An overview of the foundation design process

1996 ◽  
Vol 33 (6) ◽  
pp. 956-983 ◽  
Author(s):  
Dennis E Becker
Keyword(s):  
Design Process ◽  
Theoretical Models ◽  
Mean Value ◽  
Limit States ◽  
Foundation Design ◽  
The North ◽  
Working Stress ◽  
Characteristic Value ◽  
Partial Load ◽  
Resistance Approach

This paper examines the foundation design process in terms of level of safety associated with current state-of-practice, sources of uncertainty and how they are handled, importance of engineering judgement and experience, and the role of codes of practice. Working stress, limit states, reliability-based design approcahes are described and discussed in terms of their historical development, fundamental bases and differences, advantages, and limitations. Limit states are conditions under which a structure no longer performs its intended function. Limit states design considers seperately the two classes of ultimate and serviceability limit states using partial factors of safety. The European factored strength approach and the North American factored overall resistance approach are compared and discussed. The factored resistance approach is a logical extension of working stress design and has the significant advantage that it reflects not only uncertainty in strength, but also in theoretical models, site conditions, construction tolerances, and failure mechanisms. The partial load and resistance factors are interrelated and are a function of characteristic values. A consistent, rational basis for the selection of the geotechnical characteristic value is required. The use of a conservatively assessed mean value is recommended, and an approach for its interpretation is presented. Key words: limit states design, working stress design, characteristic value, partial factors, factored resistance, load and resistance factor design.

scholarly journals Use of Shear Wave Velocity for Foundation Design

2021 ◽  
Author(s):  
Harry George Poulos
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Small Strain ◽  
Deep Foundations ◽  
Foundation Design ◽  
Suggested Approach ◽  
Load Tests ◽  
Pile Load Tests ◽  
Design Calculations

Abstract This paper describes an approach for utilizing in-situ measurements of shear wave velocity Vs to carry out preliminary and check design calculations for shallow and deep foundations. For estimates of foundation movements, Vs can be used directly to estimate the small-strain stiffness of the soil or rock strata, while for ultimate capacity calculations, use is made of empirical correlations between Vs and penetration resistance measures, which in turn are correlated to the foundation resistance characteristics. The approach is applied to a series of published tests on shallow footings, and on a series of pile load tests for a very tall building. For these cases, comparisons of the calculated with the measured load – settlement behaviour indicates that the suggested approach provides a reasonable, albeit somewhat conservative, level of agreement.

scholarly journals Pemodelan Penurunan Pondasi Struktur Bangunan di Tanah Lunak Kota Banjarmasin Menggunakan Ansys

2021 ◽  
Vol 5 (2) ◽  
pp. 117-130
Author(s):  
Darmansyah Tjitradi ◽  
Eliatun Eliatun ◽  
Oktafianus Steven Tjitradi
Keyword(s):  
Bearing Capacity ◽  
Structural Damage ◽  
Soft Soil ◽  
Soft Clay ◽  
Structural Models ◽  
Differential Settlement ◽  
Foundation Settlement ◽  
Structural Elements ◽  
Ansys Software ◽  
Clay Type

The soil in Banjarmasin City is of soft clay type having a very low bearing capacity. Hence, it is normal for buildings in this area to have gelam wooden piles as part of the foundation. Foundations based on gelam wooden piles rely on friction which results in the building experiencing differential settlement, tilt, and cracks on the structural elements. This foundation settlement will be modeled using ANSYS software involving fifteen building structural models with brick walls under loads according to SNI 1727:2013 and due to settlement at the support. The modeling aims at understanding the effects of using tie beams on the pattern of structural damage in buildings that experience differential settlement on soft soil. Hasil penelitian menunjukkan bahwa penggunaan tie beam pada pondasi pada tanah lunak berpengaruh terhadap pola kerusakan. Pada tanah keras, ini tidak membawa efek seperti itu tetapi sebaliknya, itu meningkatkan tingkat ketidaktentuan statis struktur. Dalam kasus portal bentang tunggal, pola retakan menyerupai huruf "V" terbalik jika penurunan terjadi pada tumpuan samping. Di portal bentang ganda, di sisi lain, pola retakan dinding bata menyerupai huruf "V" jika penurunan terjadi pada penyangga samping, dan "V" terbalik jika terjadi di antara penyangga.

scholarly journals Limit States Design (LSD) for Shallow and Deep Foundations

2004 ◽  
Author(s):  
Kevin Foye ◽  
Grace Abou-Jaoude ◽  
Rodrigo Salgado
Keyword(s):  
Deep Foundations ◽  
Limit States

Inelastic Dynamic Seismic Response of 15-Story and 25-Story RC Buildings with and without Shear Walls Designed with the Mexico City Building Code

2015 ◽  
Vol 665 ◽  
pp. 81-84
Author(s):  
Jorge A. Avila ◽  
Jorge Arturo Avila-Haro
Keyword(s):  
Mexico City ◽  
Soft Soil ◽  
Shear Walls ◽  
Building Code ◽  
Limit States ◽  
Foundation Design ◽  
Seismic Demands ◽  
Soil Zone ◽  
Group B ◽  
A Minor

The inelastic seismic behavior of two reinforced concrete buildings of 15-story and 25-story is compared with and without shear-walls. The resistance-seismic design and vertical loads is made according to the requirements of the Mexico City Building Code, RCDF-2004, satisfying the limit states of service and resistance: compressible seismic area, group B. Inelastic dynamic seismic responses are determined with step-by-step analysis under SCT-EW-85 record with the nominal resistance and over-resistance effects. Results show the importance of the participation of the shear-walls to help to reduction of the magnitude of structural damages during severe seismic future events. The shear walls located in adequate form inside the structure provide an excellent additional lateral stiffness to solve the common flexibility problems in the soft soil zone of the Valley of Mexico and therefore to avoid severe additional torsion problems. In the shear wall constructions we should pay special attention to the foundation design. It was verified that the shear strengths of the structural elements selected were higher than the seismic demands. In the cases of over-strengths considered, it can be concluded that had a minor incursion in the interval of inelastic performance compared with the inelastic performance presented in the cases of nominal strengths.

Deep foundation design in the new Ontario Highway Bridge Design Code

1983 ◽  
Vol 20 (1) ◽  
pp. 173-176
Author(s):  
Bengt H. Fellenius ◽  
Geoffry G. Meyerhof
Keyword(s):  
Dynamic Monitoring ◽  
Pile Groups ◽  
Design Code ◽  
Bridge Design ◽  
Limit States ◽  
Foundation Design ◽  
Deep Foundation ◽  
Capacity Limit ◽  
Load Tests ◽  
High Level

A review is presented of some aspects of deep foundation design in the new Ministry of Transportation and Communications of Ontario, ultimate limit states Bridge Design Code. The design of axial pile capacity distinguishes between structural capacity limit and geotechnical capacity limit. The geotechnical capacity of a driven pile is governed by the dynamic impedance of the pile cross section. Higher geotechnical capacity, for instance due to soil setup, can only be utilized if proven to exist. Different capacity modification factors are used for routine load tests and high level test loading. Modern methods of dynamic monitoring are included and capacity determination by such methods is accepted as equivalent to determination from routine load tests. Lateral capacity of single piles and group piles, downdrag, and inclined loading of pile groups are considered, as are details such as splicing and use of pile shoes. Pile spacing is given as a function of expected pile length.

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