Archive | 2021
The advantages and disadvantages of the NEHRP soil classification
Abstract
The influence of local ground conditions on the parameters of seismic vibrations is the subject of study in seismic microzonation. This section of engineering seismology underwent radical changes at the end of the last century. The Commission on Seismic Safety of the National Institute of Building Sciences of the United States, as part of the implementation of the National Earthquake Damage Reduction Program, developed new NEHRP Recommendations, which are significantly different from all that has been used in the world practice of anti-seismic construction. The main provisions of this NEHRP classification have been adopted in many national building codes, including Eurocode 8 and Kazakhstan s seismic regulations. One of the essential features of the classification is the use of the average values of the velocities of transverse waves and the densities of the ground thickness with a thickness of 30 meters. In Russia, the provisions of the NEHRP norms have not yet been properly developed. Currently, the issue of extending the norms of Kazakhstan to the entire territory of the CIS countries is being considered. For this reason, the article examines in detail both the advantages and disadvantages of the NEHRP Recommendations in order to extract useful experience and adapt to the realities of Russian anti-seismic construction. In particular, the error in the representation of the parameters of the soil mass by average values is shown. The ways of overcoming the identified shortcomings of the description of the soil mass with the help of model representations are outlined