Probabilistic limiting tolerable displacements for serviceability limit state design of foundations

Zhang, L.M.; Ng, Agnes M.Y.

doi:10.1680/ravige.34860.0013

Cited by 18 publications

(32 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…10, we show the comparison between these empirical curves and the analytical fragility curves proposed in this paper, considering the shallow foundation case. It can be seen that the curve built for limit state LS2 (moderate damage) is in good agreement with the empirical curve for tolerable settlements as proposed by Zhang and Ng (2005). The curve built for limit state LS4 (complete damage) corresponds to the observed intolerable settlements one.…”

Section: Validation Of the Proposed Fragility Curvessupporting

confidence: 81%

“…Some preliminary fragility curves are proposed with respect to the magnitude of differential ground displacement. It can be seen that the curves correspondCorrespondence to: C. Negulescu (c.negulescu@brgm.fr) ing to limit states LS2 (moderate damage) and LS4 (complete damage) in the present study, correspond respectively to the "tolerable settlements" "observed intolerable settlements" curves proposed by Zhang and Ng (2005). …”

supporting

confidence: 70%

“…The empirical curves provided by Zhang and Ng (2005), are constructed by using values of the mean and standard deviation of the limiting tolerable and intolerable settlements from 95 observations for which information on building, foundation and settlements were available. Table 4 provides a summary of the number of buildings (out the 95), observed in each state ("tolerable" or "intolerable" case), with respect to different settlements intervals, and considering different foundation types (shallow foundations only and all types of foundations).…”

Section: Validation Of the Proposed Fragility Curvesmentioning

confidence: 99%

“…10. Comparison between the proposed analytical fragility curves and the empirical ones provided by Zhang and Ng, corresponding to the settlements observed on 95 buildings (see Zhang and Ng, 2005). fragility. It can be seen that the HAZUS values proposed for settlements are in good agreement with the ones obtained from the proposed LS4 curve (complete damage), contrary to the lateral spread case.…”

Section: Validation Of the Proposed Fragility Curvesmentioning

confidence: 99%

See 3 more Smart Citations

Parametric studies and quantitative assessment of the vulnerability of a RC frame building exposed to differential settlements

Negulescu¹,

Foerster²

2010

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract. The aim of this paper is to propose a simplified methodology to evaluate the mechanical performances of buildings exposed to landslide hazard, by using procedures inspired from the seismic risk analysis, such as the Capacity Spectrum Method (ATC 40, 1996). Landslide hazard involves so many aspects, that quantitative vulnerability assessment requires to consider one basic scenario at a time, i.e. one typology for the landslide hazard and one for the structural element considered. In this paper, we propose to assess vulnerability for simple one bay-one storey reinforced concrete (RC) frame structures subjected to differential settlements, using 2-D parametric nonlinear static time-history analyses. After a short review of methods used in practice to estimate building deformations induced by ground movements (e.g. differential settlements), we present the parametric studies carried out to identify the most relevant parameters, in order to predict the structural damage, as well as the methodology to develop analytical fragility curves, that can be used to quantitatively evaluate the structural vulnerability in landslide risk analyses. Different types of parameters that could influence structural behaviour have been examined in this analysis: foundation type (i.e. different combinations of links), cross-section geometry, section reinforcement degree, displacement magnitudes and displacement inclination angles. We show that the magnitude and inclination angle of displacements can be used as two relevant parameters for this type of landslide scenario. Based on these results, some simulations are conducted using the software SeismoStruct (SeismoSoft, 2003), and the proposed structural damage levels consider the local strain limits of steel and concrete constitutive materials. Some preliminary fragility curves are proposed with respect to the magnitude of differential ground displacement. It can be seen that the curves correspondCorrespondence to: C. Negulescu (c.negulescu@brgm.fr) ing to limit states LS2 (moderate damage) and LS4 (complete damage) in the present study, correspond respectively to the "tolerable settlements" "observed intolerable settlements" curves proposed by Zhang and Ng (2005).

show abstract

Section: Validation Of the Proposed Fragility Curvessupporting

confidence: 81%

supporting

confidence: 70%

Section: Validation Of the Proposed Fragility Curvesmentioning

confidence: 99%

Section: Validation Of the Proposed Fragility Curvesmentioning

confidence: 99%

See 2 more Smart Citations

Parametric studies and quantitative assessment of the vulnerability of a RC frame building exposed to differential settlements

Negulescu¹,

Foerster²

2010

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

show abstract

“…The magnitude of allowable displacements for various structures has been discussed in the literature (Skempton & MacDonald, 1956;Burland & Wroth, 1974;Barker et al, 1991;Zhang & Ng, 2005). However, the tolerable settlements of single deep founda-tions are not well defined.…”

Section: Introductionmentioning

confidence: 99%

Service limit state resistance factors for drilled shafts

Misra¹,

Roberts²

2009

Géotechnique

View full text Add to dashboard Cite

The analysis of bored piles, or drilled shafts, at the service limit state is important when foundation settlements are critical to the operation of a structure. The t-z method is a widely used soil-structure interaction model for the analysis of drilled shaft settlement. In current practice, nominal values of soil stiffness and strength parameters are used to determine settlement based upon the t-z method. However, the nominal values can vary from one designer to another, making the results somewhat inconsistent. By considering reliability-based design principles, probabilistic relationships can be incorporated into the settlement analysis of the drilled shaft, and thus design uncertainty can be quantified. Following this approach, load and resistance factor design (LRFD) procedures may be utilised and resistance factors established for use in design. Using a t-z model and the Monte Carlo simulation process, probability distributions are determined for drilled shaft capacity at the service limit state. Resistance factors are calculated based upon these relationships. The drilled shaft geometry and the shaft/soil interface parameters are varied so that their effects on the resistance factors may be understood.KEYWORDS: limit state design/analysis; numerical modelling; piles; settlement; soil/structure interaction L'analyse de pieux forés, ou d'arbres percés, à l'état limite de service est importante lorsque le tassement des fondations joue un rôle critique dans l'utilisation d'une structure. La méthode t-z est un modèle très répandu d'interaction sol -structure pour l'analyse du tassement des arbres percés. Dans les applications actuelles, on utilise des valeurs nominales de rigidité du sol et des paramètres de résistance afin de déterminer le tassement sur la base de la méthode t-z. Toutefois, les valeurs nominales peuvent varier d'un concepteur à un autre, en produisant ainsi des résultats quelque peu irréguliers. En examinant des principes conceptuels basés sur la fiabilité, des rapports probabilistes peuvent être incorporés dans l'analyse du tassement de l'arbre foré, et on est alors en mesure de quantifier l'incertitude conceptuelle. En suivant ce principe, il est possible d'utiliser des procédures d'étude du facteur de charge et de résistance, et d'établir des facteurs de résistance, qui seront utilisés dans la conception. On procède à la détermination de distributions de la probabilité en appliquant le modèle t-z et la technique de simulation Monte-Carlo, pour la capacité des arbres percés à l'état de service limite. Des facteurs de résistance sont calculés sur la base de ces rapports, et on varie la géométrie des arbres percés et les paramètres d'interface arbre/sol afin de comprendre leurs effets sur les facteurs de résistance. INTRODUCTIONThe geotechnical design of drilled shafts, also known as bored piles, has traditionally followed the allowable stress design (ASD) methodology at the axial ultimate limit state, assuming full resistance of the soil along the length of the shaft and at the tip. In the ...

show abstract

A 3D Numerical Approach to Assess the Temporal Evolution of Settlement Damage to Buildings on Cavities Subject to Weathering

2018

View full text Add to dashboard Cite

The goal of this paper is to show how a recently developed advanced chemo-hydro-mechanical (CHM)-coupled constitutive and numerical model for soft rocks can be applied to predict the temporal evolution of settlement damage to buildings on cavities subject to weathering. In particular, a Building Damage Index (BDI) and its evolution with time is proposed. The definition of the BDI is inspired by the work of Boscardin and Cording (J Geotech Eng 115:1-21, 1989) and uses the surface differential settlements obtained by finite element (FE) analyses to assess how far a building is from a non-acceptable service condition. By modelling the reactive transport of chemical species in 3D and using a coupled CHM constitutive and numerical model, it is possible to simulate weathering scenarios and monitor the temporal evolution of surface settlements making the BDI time dependent. This approach is applied to evaluate the damage evolution of two buildings lying on two anthropic caves in a calcarenite deposit belonging to the Calcarenite di Gravina Formation. Standard and advanced experimental tests are performed on the in situ material, and the results are used to calibrate the constitutive model. The soundness of both constitutive relationship and reactive transport solver is subsequently tested by simulating two laboratory-scale boundary value experiments. The first is a model footing test on dry and wet calcarenite, while the second is a small-scale pillar that, after the saturation-induced short-term water weakening, fails due to a long-term dissolution weathering process. Finally, both 2D and 3D coupled FE analyses simulating different weathering scenarios and corresponding settlements affecting the buildings above the considered cavities are presented. Particular attention is placed on assessing the BDI and its temporal evolution. Keywords

show abstract

Probabilistic limiting tolerable displacements for serviceability limit state design of foundations

Cited by 18 publications

References 0 publications

Parametric studies and quantitative assessment of the vulnerability of a RC frame building exposed to differential settlements

Parametric studies and quantitative assessment of the vulnerability of a RC frame building exposed to differential settlements

Service limit state resistance factors for drilled shafts

A 3D Numerical Approach to Assess the Temporal Evolution of Settlement Damage to Buildings on Cavities Subject to Weathering

Contact Info

Product

Resources

About