All Nuclear power plants consist of several structures of varying importance that have to be designed for dynamic loading like earthquakes and impacts that they might be exposed to. Research on the influence of dynamic loading from blast events is still crucial to address to guarantee the general safety and integrity of nuclear plants. Conventional structural design approaches typically ignore the Soil-Structure Interaction (SSI) effect. However, studies show that the SSI effect is significant in structures exposed to dynamic loads such as wind and seismic loads. The present study is focused on evaluating the Soil-Structure Interaction effects on G + 11 storied reinforced concrete framed structure exposed to unconfined surface blast loads. The SSI effect for three flexible soil bases (i.e., Loose, Medium, and Dense) is evaluated by performing a Fast Non-linear (Time History) Analysis on a Two-Dimensional Finite Element Model developed in (Extended Three-Dimensional Analysis of Building System) ETABS software. Unconfined surface blast load of three different charge weights (i.e., 500 kg TNT, 1500 kg TNT, and 2500 kg TNT) at a standoff distance of 10 m are applied on the structure. Blast wave parameters are evaluated based on technical manual TM-5-1300. The blast response of the structure with and without the SSI effect is studied. It is concluded from this study that, there is a significant variation in dynamic response parameters of the structure with flexible soil bases compared to rigid or fixed base. For all magnitudes of surface blasts and soil base conditions, the ground floor is the most vulnerable floor against collapse. The study recommends measures to mitigate the damage due to unconfined surface blasts on multi-storey reinforced concrete structures.

Precisely estimating the lateral capacity of the large-diameter monopile is essential for securing the stability of the fixed wind turbine of high power generation. Conventional standards relying on p-y curves often underestimate the monopile-soil interaction due to their failure to account for pile shaft rotations and base effects, leading to overly cautious lateral capacity designs. This paper introduces the three-spring soil reaction model that comprehensively considers lateral soil resistance, shaft frictional resistance, base shear force, and base moment. The analytical expressions for three springs are established considering the self-similarity between soil stress-strain relationships and load-displacement responses. The bearing capacity calculation method of monopiles with varying rigidity is developed based on the combinations of three springs. The results reveal that the modified p-y curve for lateral capacity predictions achieves over 80% accuracy. The contributions of base effects and shaft frictional resistance to bearing capacity gradually increase with the increases in pile rigidity, and the correction of monopile ultimate lateral displacement prediction is also enhanced.

Seismic load is a critical load that can trigger damage or collapse of structures, especially in earthquake -prone areas. The susceptibility of structures to seismic loads is influenced by factors related to soil characteristics and structural behavior. This paper comprehensively examines the development of Indonesian seismic code design parameters and their comparison with the current seismic code. The results of the analysis showed that the design spectral acceleration of short -period AD and long -period A1 SKBI 1987 and SNI 2002 increased with increasing PGA values, with a consistent pattern of SC < SD < SE. Unlike the previous two codes, design spectral acceleration AD and A1 SNI 2012 and SNI 2019 experience fluctuations in all types of soil. The ratio design spectral acceleration of AD and A1 SNI 2019 to KBI 1987 and SNI 2002 varies; there are up, fixed, and down for SC, SD, and SE soil conditions. The ratio of design spectral acceleration AD and A1 SNI 2019 to SNI 2012 designs also varies; this condition is due to changes in site coefficients. There were significant changes to the SKBI 1987 and SNI 2002 structural systems, especially the low and medium seismic levels. The increase in the seismic influence coefficient ratio of some cities varies for each type of soil and code. The increase in the 1970 PMI seismic coefficient was < 30% for all soil types, and the highest percentage increase occurred in SC soil types. The increase in seismic coefficient in SKBI 1987, SNI 2002, and SNI 2012 is more dominant in SE soil types.