Piles should possess the structural integrity to carry the design load and transfer to the soil/rock below. As per Indian standard IS 14893:2001, in general following defects are observed in the pile, which may lead to catastrophic failure. (a) Pile shaft necking, (b) Discontinuity of concrete, (c) Intrusion of foreign matter, (d)Improper toe formation due to contamination of concrete at the base with soil particles, (e) Washing of concrete due to high water current, and (f) Poor quality control with improper construction methods. NDT-based low strain pile integrity testing can be effectively used for evaluation of quality and acceptance of pile foundations. Low strain pile integrity test is based on pulse echo method. Pile integrity tester gives the velocity plot versus time. The plot is observed for the reflections, which indicate the change in the property of wave passing medium. The reflections may be due to soil resistance (stiffness) effects, cross-sectional changes, and soil property changes. In this study, bored cast-in-situ piles are evaluated for its integrity.

No abstract

No abstract

Open ground storey buildings have consistently shown poor performance during past earthquakes across the world. For example during 1999 Turkey, 1999 Taiwan and 2003 Algeria earthquakes, a significant number of them have collapsed. For instance, the city of Ahmedabad alone has about 25,000 five-storey buildings and about 1,500 eleven-storey buildings; majority of them have open ground storey. There are huge numbers of such buildings in urban areas of moderate to severe seismic zones of the country. The collapse of more than a hundred reinforced concrete frame buildings with in Ahmedabad (~225km away from epi-centre) during the 2001 Bhuj earthquake has emphasised that such buildings with open ground storey are extremely vulnerable under earthquake shaking. The presence of walls in upper storeys makes them much stiffer than the open ground storey. Still Multi storey reinforced concrete buildings are continuing to be built in India which has open ground storeys. These buildings are not designed as per the earthquake resistant design. It is imperative to know the behaviour of soft storey building to the seismic load for designing various retrofit strategies. Hence it is important to study and understand the response of such buildings and make such buildings earthquake resistant based on the study to prevent their collapse and to save the loss of life and property. Based on the above an attempt is made in this paper to assess the seismic performance of the soft storey reinforced concrete building by shake table test