CASE STUDY ON TYPE OF FAILURE

PREPARED BY:- NITIN KHAMBHALIYA(14SOECV11027) HITESH KHANTANA (14SOECV11028) CHIRAG KHUNT (14SOECV11029) RAVI KARSARIYA (14SOECV11024)

AbstractMany structures are built with foundations that are

inadequate for the soil conditions existing on the site. Sometimes due to the lack of suitable land, structures

are often built on marginal land that has insufficient bearing capacity to support the substantial weight of a structure.

A foundation usually rests in the top-most layer of soil and if the soil conditions change, it may no longer be able to support the full weight of the foundation.

Identification of foundation failures and providing needful treatment is very important since, the failure modes of foundations under different loadings are asymmetry and complex.

AbstractThe paper reviews different failure modes

of foundations such as Load transfer failures Design & Construction errors Lateral movements Vibrating effects Floating & water level changes

Introduction Foundations of engineering constructions

are systems that act like interface elements to transmit the loads from superstructure to, and into, the underlying soil or rock over a wider area at reduced pressure.

Broadly foundations are classified as shallow foundation and deep foundation.

Load transfer failuresThe objective of foundation is to transfer the load on

superstructure to the foundation soil on a wider area. It works as an interface between superstructure (over the

ground) and substructure (under the ground). The size of the footing is decided in such a way that it

distributes the pressure on the subsoil and it is expected that the applied pressure never exceeds the permissible limit of the subsoil.

A factor of safety in geotechnical design is adopted to take care of different sources of uncertainty involved in geotechnical design and practice.

Load transfer failures

Fig 1:-load transfer failure

LATERAL LOADS

Lateral movement in soil is possible when there is removalof existing side support adjacent to a building or there isexcessive overburden on backfill or lateral thrust on the backside of a retaining wall.

Lateral movement is also observedduring earthquake when structure fails due to lateral movementof soil beneath the foundation following liquefaction.

Classic examples of such failures are as follows Figure-2

LATERAL LOADS

Fig :-2 lateral load

Design & Construction errors There are two common sources of the construction errors, (i) Temporary protection measures (ii) Foundation work itself. This paper presents a classic case of poor construction

practice due to which foundation failure of a building in Shanghai, China took place (Figure 3).

An unoccupied 13-storey block of flat building, still under construction, at Lianhuanan Road in the Minhang district of

Shanghai city toppled over and ended up lying on its side in a muddy construction field. The cause of the building collapse

in Shanghai was due to a pressure difference on two sides of the structure.

Design & Construction errors

Fig:-3 construction errors

Design & Construction errors

Figure 4. (a) Apartment building was constructed, (b) It was decided for anunderground garage to be dug out. The excavated soil was piled up on theother side of the building (c) Final failure of building

CONCLUSION

The paper reviewed and discussed the various causes of foundation failure as well as their possible preventive /remedialmeasures through case studies.

Information on available literatures is provided to help in identifying the potential

foundation problem in advance and taking necessary and appropriate action for mitigation purpose.

REFERENCES [1] Bowles, J. E. (1996). Foundation Analysis and

Design. McGraw – Hill Publications [2] Leonards, G. A. (1982). Investigation of

failures, Journal of Geotechnical Engineering, ASCE, 108, No. GT-2, 187-246

[3] Phoon, K. K., & Kulhawy, F. H. (1999a). Characterization ofgeotechnical variability. Canadian Geotechnical Journal, 36, 612-624.

[4] Phoon, K. K., & Kulhawy, F. H. (1999b). Evaluation of geotechnical property variability, Canadian Geotechnical Journal, 36, 625-639.

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