Analysis of methods for calculating long-span multi-span structures for seismic stresses

Abstract

The consideration of structural length when calculating seismic force effects is one of the pressing issues that interests today's engineers. Numerous studies conducted on bridges demonstrate that their supports oscillate asynchronously under seismic forces, indicating the need for a new approach in assessing earthquake forces. The asynchronous oscillations of supports lead to both changes in inertial seismic loads and the formation of quasistatic forces associated with the relative displacement of supports. This presents a critical problem for statically indeterminate structures, which are highly sensitive to support displacements. Based on the experience of past earthquakes, the building codes of most countries, including Russia, prohibit the construction of hingeless arched domes on rocky soils in seismically hazardous areas. Although the seismic loads on these domes are not significant, they are often prone to damage as a result of seismic impact. Thus, the analysis of damage in multi-span bridge structures indicates the need for specific development of calculation methods that take into account various types of support vibrations. This article analyzes research conducted specifically on this topic.