Design energy input spectra for high seismicity regions based on Turkish registers

Abstract

SUMMARY:This work proposes design energy spectra in terms of an equivalent velocity, intended for regions with design peak acceleration 0.3 g or higher. These spectra were derived through linear and nonlinear dynamic analyses on a number of selected Turkish strong ground motion records. In the long and mid period ranges the analyses are linear, given the relative insensitivity of the spectra to structural parameters other than the fundamental period; conversely, in the short period range, the spectra are more sensitive to the structural parameters and, hence, nonlinear analyses are required. The selected records are classified in eight groups with respect to soil type (stiff or soft soil), the severity of the earthquake in terms of surface magnitude M s (M s  5.5 and M s > 5.5) and the relevance of the near-source effects (impulsive or vibratory). For each of these groups, median and characteristic spectra are proposed; such levels would respectively correspond to 50% and 95% percentiles. These spectra have an initial linear growing branch in the short period range, a horizontal branch in the mid period range and a descending branch in the long period range. Empirical criteria for estimating the hysteretic energy from the input energy are suggested. The proposed design spectra are compared with those obtained from other studies.

Preliminary ranking of alternative scalar and vector intensity measures of ground shaking

“…The energy-based demand parameters (see e.g. Benavent-Climent et al 2002, López-Almansa et al 2013) such as the normalized hysteretic energy, or the ratio of normalized hysteretic energy to normalized maximum displacement (also known as equivalent number of cycles) are then of major importance to be considered. In fact, they can be more effective than the displacement-based demand parameters especially in building designed according to old codes.…”

Hysteretic Energy Demand in SDOF Structures Subjected to an Earthquake Excitation: Analytical and Empirical Results

“…Consequently, the energy balance equation of an SDOF system can be written as in the form of its well-known expression from dynamics of structures as given in Eq. (1) [2,4,5,13,15,21,25,26,32,37,40,41,46]. In the basic energy balance equation; m is the seismic mass of the structure, c is the damping coefficient, u is the relative displacement of the system, fs is the restoring force, ( ) is the horizontal ground acceleration, ( ) is the relative velocity and ( ) is the relative acceleration of the system.…”

“…Based on analysis of SDOF systems having elasticperfectly plastic restoring force characteristics, Akiyama expressed the ratio of damage velocity (as a function of the energy contributing to damage) to the equivalent velocity (as a function of EI) in terms of the viscous damping ratio (). At the end of the earthquake ground motion duration since EK and ES components are almost zero, the energy which contributes to structural damage can be approximately taken equal to the hysteretic energy EH [40]. Accordingly, Akiyama's empirical expression is given below [3]:…”

A new steel framing system for seismic protection of timber platform frame buildings. Implementation with hysteretic energy dissipators

“…The vertical distribution of the yielding shear forces V yi of the i ‐th story is selected in this subsection following the three approaches described in Section 6. It is initially assumed that the fundamental period of the building after the yielding of the flexible steel plates is T F = 1 s and that the corner period corresponding to the characteristic spectrum is T G = 0.32 s (, see Figure ). Given that (Section 6), Equation converts into …”

“…Because design spectra are commonly derived after a large number of representative strong seismic ground motions, this strategy can provide an adequate level of safety. Among other researchers, Benavent-Climent et al [20] proposed design energy input spectra for moderate seismicity regions, and Benavent-Climent et al [21][22][23] proposed design energy input spectra for moderate-to-high seismicity regions based on Colombian and on Turkish records, respectively. These V E input energy spectra depend on the soil characteristics (stiff/soft), the seismic design acceleration, the magnitude of the expected earthquakes (M s ≤ 5.5 and M s > 5.5), and the type of seismic input (impulsive / vibratory); conversely, they depend neither on the mass nor on the damping parameters.…”