THE ESTIMATION OF BUILDINGS’ VULNERABILITY AND EXPERIENCE IN APPLICATION OF MODERN

SEISMIC PROTECTION SYSTEMS IN ARMENIA

PhD. Z. Khlghatyan, PhD. V. Arzumanyan, Assist. H. Ktunyan, V. Manusagyan, A. Martirosyan

Earthquake Engineering Centre (EEC) of National Survey for Seismic Protection (NSSP) RA, Davidashen 4 Massive, Yerevan, 375054,

Armenia. E-mail: office@nssp-gov.am

INTRODUCTION

At the end of XX century the basic attention, at both national and international levels, in the sphere of population protection against catastrophes in general and against seismic disaster in particular, was given to a problem of Rehabilitation.

In this regard, at the end of XX century, the more attention has been paid to the idea of a priority of Preparedness over Recovery and, accordingly, to the strategy of Seismic Risk Reduction.

According to it, the programs of seismic risk reduction has been established by the Government of Armenia on the territory of Yerevan (resolution of the Government of Armenia N392 from 07.06.1999) and on the territory of Armenia (resolution of the Government of Armenia N429 from 07.06.1999).

In these programs, the problem of residential buildings vulnerability assessment and reduction takes the special place.

In Armenia, after the Spitak earthquake, huge amount of studies concerning the surveys of residence and public buildings as well as industrial, energy and other critical objects were accomplished, which gave an opportunity to estimate actual bearing capacity of buildings and structures at expected calculated seismic effects. Based on the results of those surveys the databank on technical state of buildings, structures and critical objects of cities and other settlements of Armenia was created in Armenian NSSP. Seismic risk assessment for Yerevan and Armenia was given.

Simultaneously, the available base of the normative-technical documentations on both new construction and strengthening and restoration of damaged at earthquakes buildings and structures were reconsidered. The following normative-technical documents were designed and introduced within a rather short period of time after the earthquake:

CNRA (Construction norms of RA) II-2.02-94. Seismic Resistant Construction. Norms of Design. Yerevan. 1995.

CNRA (Construction norms of RA) IV-13.01-96. Masonry and reinforced-masonry constructions. Yerevan. 1996.

CNRA (Construction norms of RA) I-2.01-99. Engineering survey for construction. The basic standings. Yerevan. 1999.

Basic standings of system of the normative-technical documents in the field of construction. Yerevan. 1994.

Methodical recommendations on survey of technical state of residence and public buildings. Yerevan. 1996.

Recommendation for restoration and strengthening of bearing structures in residence houses. Yerevan. 1996.

Low for seismic protection. Yerevan 2002.

THE ESTIMATION OF BUILDING ’S VULNERABILITY

By the constructive decisions residential buildings in Armenia are divided into three categories:

stone buildings (less than 5 storey )

frame-panel buildings (9 storey )

large-panel buildings (9 storey )

frame and frame-braced (12-16 storey )

consructed by floor-grade method (12-16 storey)

stone buildings (less than 5 storey )

stone buildings (less than 5 storey )

frame-panel buildings (9 storey ) of 111 series

large-panel buildings (9 storey )

frame-braced (12-16 storey )

frame (9 storey)

consructed by floor-grade method (12-16 storey)

4- storey stone buildingsa) Fragment of the schematic plan

4- storey stone buildings

b) back facade

EXPERIENCE IN APPLICATION OF MODERN SEISMIC PROTECTION SYSTEMS IN ARMENIA

The projects on seismic protection of 9-story buildings of the 111 series using a 1. method of additional so called ‘’upper flexible storey ‘’ in form of dynamic vibrational damping (Korenev B. G., Khlghatyan Z. M.) and 2. a method of seismic isolation of building (M.Melkumian) at its foundation level with use of laminated rubber bearings (LRB) were designed and implemented by Armenian NSSP for stone 5-story stone building. These methods can be used without evacuation of population

3. Another original method was realized in Gumri during reinforcement of 5-story stone building (copyright certificate №769A2, E04H9/02, authors R. Badalyan, Z. Khlghatyan, K. Babakhanov) (fig. 6). Unlike traditional solutions in this case the stiffness diaphragms were placed outside of building forming reinforcement concrete rigid building braced by joint with the main building (‘’braced systems’’ ).

Testing of LRB in the EEC accredited lab, Armenian NSSP

Seismic protection of 9-story building in the zone of the Spitak earthquake, using a method of additional “upper

flexible floor”.Model of 9-storey frame building with “upper flexible

floor”(scale 1:5)General view of a building with “upper flexible floor”

a b.

c.

Seismo isolation of a 5-story stone building in the zone of Spitak

earthquake using laminated rubber bearings (LRB)

aSchematic section of a 5- story stone building

with LBR.bGeneral view of a

seism isolated stone dwelling house.

cGeneral view of LBR, set between a building

and base.

5-storey stone building in Gumri before the rehabilitation

5-storey stone building in Gumri after the rehabilitation (back façade)

5-storey stone building in Gumri after the rehabilitation (general view)

Theoretical results of “braced system”a. Design scheme of the ‘’braced systems’’

b. Variation of seismic forces of floors depending on time during the earthquake

c. Variation of displacements of floors depending on time during the earthquake building without rigid extension

building with rigid extension rigid extension