Seismic evaluation of pile groups

Abstract

In certain regions of the country, designing deep foundations to withstand seismic loading is a reality. Seismic loading of structures and foundations reach a critical state as the laterally applied force increases. Especially liquefaction is the major effect on laterally loaded piles. So firstly, the liquefaction potential of the site has been evaluated to make the best seismic assessment, as studied in the following chapter. Since, liquefaction potential analysis is highly complex and is based on numerous variables such as moment magnitude, epicentrical distance, PGA, thickness of soil layers, overburden pressure and duration of motion etcetera. Most of the potential analysis methods are empirically based on the statistical measurements of known past earthquakes. Thus, firstly the liquefaction potential analysis of the site is evaluated. by means of these methods. Secondly, the effects of liquefaction-induced lateral spreading on piles have been studied. Then, after a brief information is given about the structure, which is chosen as the model, the capacity estimations of the piles and the superstructure are acquired. Then soil, piles and the superstructure are modeled together in the SAP2000 computer program. Liquefaction-induced lateral spreading, spectral analysis (for TSC-98) and non-linear time-history analysis, with three different earthquake records (two of them are simulated), are examined. Finally, the results of the most critically forced structural elements are illustrated and then compared both by the structural capacity and between the different methods of solutions used. This study also gives a general knowledge about the sufficiency of the Turkish Seismic Code for buildings within the vicinity of an active fault line.