Soil‐structure interaction effects on the fundamental periods of the shear‐wall dominant buildings

Abstract

Shear-wall dominant reinforced concrete buildings constructed with tunnel-form technique are prevalently constructed in regions with high seismicity due to their ease of construction and inherent resistance to lateral forces. However, the current seismic codes and the design provisions constitute inadequate guidelines for the earthquake-resistance design of these buildings. In particular, the prediction of their fundamental periods via current empirical expressions yields not only erroneous results, but also ignores soil-structure interaction (SSI) effects. For the objective of understanding their dynamic characteristics, a series of eigen analyses is conducted with and without considering SSI effects. The soil effects on foundations are represented by linear translational and rotational winkler springs, and rigidities of the springs are computed from the foundation size and the uniform soil compressibility. An ensemble of 140 different shear-wall dominant buildings with varying heights is simulated in three-dimensions considering four different soil conditions. It is proven that the vibration periods and the mode shapes of the shear-wall dominant buildings may change depending on the different soil conditions. Based on the results of the three dimensional fi nite element analyses, a set of new empirical equations was proposed to predict the fundamental periods of the shear-wall dominant buildings accounting the SSI effects.

Discussion of paper ‘Evaluation of building period formulas for seismic design’ by Oh‐Sung Kwon and Eung Soo Kim, Earthquake Engineering and Structural Dynamics 2010; 39(14): 1569–1583

“…The structural characteristics and the dynamic behavior of tunnel‐form buildings 5 are quite different than those of the conventional shear wall‐dominant buildings confirming the assumptions of the equation proposed by Goel and Chopra 3. Recent studies 6–8 show that current design provisions 9–12 inaccurately estimate the fundamental period and result in erroneous computation of earthquake design forces when they are used blindly for tunnel form buildings. Tunnel form buildings behave like thin‐wall‐tubular structures because they have significant slab–wall interaction.…”

“…The fundamental period calculated by the empirical formulas given in Equation () using the suggested C r factor of 0.015 for shear‐wall buildings should be used as an estimation of the fundamental period of the shear wall structure in which the significant precision is not an objective as shown in Figure 6 of the discussed paper. Additional research is needed to evaluate Equation () as well as the period Equation proposed by Balkaya and Kalkan 7 and Balkaya et al 8 by obtaining the design information for the instrumented shear wall buildings in the database. In addition to this, better explanations are needed for the outlier data points of Figure 6 of the discussed paper.…”

Practical modelling issues for masonry building retrofitted with squat shear wall

“…This model was subsequently updated by Harden and Hutchinson and later by Gajan et al Khalil et al studied the influence of soil–structure interaction on the fundamental period of buildings. Balkaya studied the soil–structure interaction effects on the fundamental periods of the shear‐wall dominant buildings. Marzban et al studied the seismic performance of reinforced concrete shear wall frames considering soil foundation–structure interaction.…”

Structural Behavior of Lightly Reinforced Shear Walls of Tunnel Form Buildings

“…The system as a whole, allows for a better organization of the construction activities enabling continuous flow of work, and a higher quality standard. The majority of multi-unit housing, single-family residences, high-rise apartment buildings, hotels, townhouses and warehouses recently constructed in Turkey utilize the tunnel-form system because of its industrialized modular construction technique and repetitive forming features [5], [6].…”

“…The system as a whole, allows for a better organization of the construction activities enabling continuous flow of work, and a higher quality standard. The majority of multi-unit housing, single-family residences, high-rise apartment buildings, hotels, townhouses and warehouses recently constructed in Turkey utilize the tunnel-form system because of its industrialized modular construction technique and repetitive forming features [5], [6].When destructive earthquakes happen, brittle failure is not desired to occur at the tunnel form buildings in which both lateral and vertical loads are assigned to shear walls [7]-[8]. Strength and ductility requirements must be satisfied considering the seismic design philosophy.…”