Finite Element Analysis of Pile Foundations Under Surface Blast Loads

摘要

Recent terrorist attacks on important buildings raised the significance of analysis of structures under blast loads in order to seek mitigations measures to have safer structures under such threats. Most of recent studies consider the superstructure only since it is the major part affected by the blast loads. However, the foundations may be affected severely as well. This can make the super-structure repair is impractical or inefficient. In this research, detailed finite element analysis using ABAQUS was used to study the effect of blast loads on the response of soil and nine reinforced concrete piles buried in the soil and connected by a 10 m × 10 m × 1.0 m reinforced concrete raft. The piles have a 0.6 m diameter and a length of 20 m. Drucker-Prager Cap model was used to model the soil behavior. The model accounts for soil hardening and softening and stress path dependence. The raft and piles were modelled using 8-node solid elements with reduced integration. The concrete damage plasticity model was used to model the reinforced concrete material for the pile and raft. The blast load was considered through several explosive weights of TNT at a height of 0.66 m above ground surface. The effect of standoff distance was studied through five different distances from the raft edge. Finally, observations and recommendations were provided to enhance the response of pile foundations under blast loads.