Seismic performance of elevated steel silos during Van earthquake, October 23, 2011

Abstract

Silos are commonly used industrial structures to store dry/granular materials like cement or wheat. A typical silo consists of a vertical steel tank supported by a braced steel frame which rests on concrete support. Due to unloading purposes, the tank is generally located at an elevated position. This makes the structure vulnerable to axial loads in columns due to excessive overturning moments generated at the base of the structure. During the October 23, 2011 Van earthquake in Turkey, many silos collapsed either due to column buckling or foundation problems. In this paper, the field observations regarding the seismic performance of silos after the Van earthquake are first summarized. Then, the seismic performances of two steel-elevated silos located in the earthquake region are studied. One of the silos survived the earthquake by some minor damages in the form of buckling (at bottom horizontal brace) and spalling of concrete support, while the other silo remained undamaged. Nonlinear dynamic time history analyses are performed to evaluate the seismic performances of both silos. As the input ground motion, the recorded ground motion from a temporary aftershock station (about 2 km away from the silos) in the second earthquake is used. Analyses indicate that design and construction quality of elevated silos determine the seismic performance. Finally, recommendations are given to improve the seismic performance of new constructions.

Seismic retrofit design and risk assessment of an irregular thermal power plant building

“…As for the heavy coal bunkers installed at the level of 32.2 m, retrofit strategies are needed to reduce their adverse impact on the seismic demands of their supporting structural components. From past earthquake reconnaissance reports, similar storage silo‐shaped facilities that commonly used in industrial structures caused severe damage even collapse to the supporting structural system . Therefore, some researchers employed base isolations as a retrofit solution for existing industrial silo‐type structures with an attempt to improve their seismic performance (e.g., Kanyilmaz & Castiglioni, 2017; Fell et al 2009).…”

“…From past earthquake reconnaissance reports, similar storage silo-shaped facilities that commonly used in industrial structures caused severe damage even collapse to the supporting structural system. [31] Therefore, some researchers employed base isolations as a retrofit solution for existing industrial silo-type structures with an attempt to improve their seismic performance (e.g., Kanyilmaz & Castiglioni, 2017 [22] ; Fell et al, 2009 [32] ). As such, for the TPP building that are characterized by heavy coal bunkers, Dai et al [33] introduced a partial mass isolation system and proposed a probabilistic-based design framework.…”

Reducing the seismic vulnerability of existing elevated silos by means of base isolation devices

“…The second structural level on one side (y = +0 mm) has a concentric X-bracing with UPN200 profiles connected in the mid-section a. Supporting concrete failure [14] b. Collapse due to brittle welded connection failure [14] c. Local buckling and anchorage failure [14] (Fig.…”

“…Almost all elevated cement and wheat silos were fully collapsed or seriously damaged during this earth-quake [14]. After this event, main collapse modes were due to the rupture at the base due to excessive bending and bearing stres-ses, local buckling and anchorage failures, and welded connection failure [14,15]. These damages from the recent earthquakes high-light the vulnerability of elevated silos and the substantial need to find efficient retrofitting solutions to avoid the future disasters.…”

Seismic Retrofit of Industrial Silos by Means of Base Isolation Devices

“…Damages observed on the support structure of elevated silos after Van Earthquake (2011) Figure 10 Structural damages observed in Van Earthquake and numerically obtained failure mechanisms [3] …”