| Popis: |
Pile foundations are generally used for load carrying and transferring system. Piles are transferring the load to hard stratum. Piles are also used to resist loads from the superstructures, dynamic loads or uplift loads. Hence, piles are successfully practiced to support bridges, buildings, docks and other heavy structures across the globe. When soil is not having adequate bearing capacity or when there are boulders or cavities in soil strata or less overhead clearance or when surrounding existing structures are there, then use of number of micropiles instead of small number of piles shall be considered as micropiles have high flexibility and ductility during the seismic conditions. Micropiles are also used as an inclined member. Providing micropiles as solution in such situations is found more reliable and economical. Before 1950, micropiles were not much used due to their long flushing process. But in the 1950s in Italy, they have been invented and from that time they are widely used in all over the world. They have gained popularities to provide stability under seismic conditions. Now, various design and simulation tools are available for its design and verifications. Micropiles are often used to strengthen the existing structures among the various ground improvement techniques as it is more economical and can be used easily with latest technology of construction. In this paper, benefit of micropiles for retrofitting of bridge foundation in sandy soil, which was damaged during earthquake, is presented. The numerical simulations are done using Midas GTS software. This simulation technique is the finite element method. The effect of a different type and intensity of earthquakes on this bridge foundation is studied. Micropiles will be designed considering expected stability and economy of retrofitting among various options. |
