######## Seismic/Structural Engineering Evaluation

######## of

######## Strengthened Residential Buildings

######## Damaged in the 1988 Earthquake Zone of Armenia

**------------------------------------------------------**

######## 

**by**

**Loring A. Wyllie, Jr.**

**Senior Principal**

**Degenkolb Engineers**

**San Francisco, California**

**for**

**USAID/The Urban Institute Armenia**

**------------------------------------------------------**

**September 23, 1999**

**Degenkolb Job Number 99356.00**

#### Executive Summary

A seismic and structural evaluation of current seismic strengthening
schemes for residential construction being used in the 1988 Earthquake
Zone of the Republic of Armenia has been performed by Loring A. Wyllie,
Jr., Senior Principal of Degenkolb Engineers. Mr. Wyllie is familiar
with Armenian construction having visited Armenia in 1986 and
extensively studying the earthquake effects in 1988 and 1989 with three
trips to Armenia and the Earthquake Zone.

The buildings being strengthened are generally 5-story apartment
buildings of stone masonry construction or composite stone masonry and
concrete construction. These Soviet designs have typically performed
poorly in recent earthquakes. The buildings being strengthened suffered
only minor to moderate damage and these specific buildings did not
partially collapse in 1988.

Two basic strengthening alternatives are currently being used in Armenia
for these buildings. One is described as a "full jacket" scheme where
all interior stone wall surfaces are jacketed with concrete, floor
diaphragms and wall ties are added, and some new reinforced concrete
shear walls are added for increased seismic resistance. I believe
buildings properly strengthened by this scheme should perform well in
future earthquakes providing life-safety protection to occupants.

The second strengthening scheme observed is the "corner jacket" scheme
with short jackets only at wall intersections, only partial structural
diaphragms adjacent to the walls, and nominal seismic strengthening
consisting of new columns or pilasters beneath perimeter longitudinal
concrete beams and short new reinforced masonry walls. This scheme may
provide life-safety protection to occupants, and buildings strengthened
by this scheme should experience considerably more damage in future
earthquakes than the "full jacket" scheme.

The report concludes that strengthening these stone masonry buildings in
Armenia should be more economical than new construction of comparable
buildings. The conclusions on potential performance of the two schemes
are described above. Recommendations for improved inspection practices
are included in the report. Potential donors interested in improving the
housing situation in the Earthquake Zone are encouraged to consider
funding seismic retrofit projects and to specify their funding be used
only with the "full jacket" scheme, the designs could be peer reviewed
by an independent engineering expert and, the design engineer could be
made responsible for overseeing the construction inspection program.
These recommendations are made to provide assurances to the donor that
the future seismic performance of these strengthened buildings will be
acceptable.

Armenian national experts Edward Khachian and Mikayel Melkumyan provided
technical consultation during this visit to Armenia, and they are in
general agreement with the conclusions of this report.

#### 

#### Introduction

On December 7, 1988, a devastating earthquake occurred in Northern
Armenia centered near the city of Spitak. Considerable damage and loss
of life occurred in Spitak, Leninakan (now Gyumri), Kirovakan (now
Vanadzor), and to a lesser extent in Stepanavan. A massive project began
in 1989 to build new housing on the outskirts of Gyumri and in each of
the damaged cities with assistance from the various Soviet republics,
but the downfall of the Soviet Union and other factors prevented most of
that construction from reaching completion.

In just over 10 years since the earthquake, some of the new housing has
been completed, new units have been built, and some damaged buildings
have been strengthened and renovated. Most of the remaining damaged and
vacant buildings are 3- to 5-story stone masonry buildings which were
vacated, and people have looted and removed all fixtures, doors,
windows, etc. People have developed makeshift housing called "domics" in
which many people currently reside around their previous residences.

A recent study, "A New Housing Strategy for the Earthquake Zone, The
Republic of Armenia "dated December 1998, prepared by The Urban
Institute, has identified an official need of 26,841 housing units in
the earthquake zone and recommends strengthening and renovating 7,005
damaged units towards fulfilling that goal. The Armenian government has
identified the damaged buildings which can be strengthened and
renovated.

This report presents the results of a seismic/structural evaluation by
Loring A. Wyllie, Jr., Senior Principal of Degenkolb Engineers of San
Francisco, California, USA. The evaluation was funded by USAID through
The Urban Institute with the purpose of evaluating the effectiveness of
seismic strengthening schemes developed by Armenian engineers. Loring
Wyllie visited Armenia in late July 1999; reviewed drawings of various
strengthening schemes; had discussions with engineers, government
officials, and other interest parties; and visited the earthquake zone
to visit and inspect various strengthening projects. Loring Wyllie was
assisted by technical consultation on this evaluation by Armenia
national experts Edward Khachian and Mikayel Melkumyan, and they are in
general agreement with the conclusions and recommendations of this
report. Gohar Hovanissyan of the Engineering Research Center (ERC) at
the American University of Armenia (AUA) provided assistance throughout
the visit, and Armen der Kiureghian, ERC's Director/Dean of the
Engineering Faculty at AUA and Professor at the University of
California, Berkeley, provided a helpful briefing and guidance before
the trip.

The following is a listing of individuals who were briefed, interviewed,
or met during the site visit in Armenia:

+--------------------+-------------------+----------------------------+
| **[Republic of     |                   |                            |
| Arme               |                   |                            |
| nia]{.underline}** |                   |                            |
+--------------------+-------------------+----------------------------+
| Karapetyan, Suren  | Deputy Minister   | Ministry of Urban          |
|                    |                   | Development                |
+--------------------+-------------------+----------------------------+
| Markarian, Teimur  | Head              | Scientific Technical       |
|                    |                   | Department                 |
|                    |                   |                            |
|                    |                   | Ministry of Urban          |
|                    |                   | Development                |
+--------------------+-------------------+----------------------------+
| Khachatrian, Kamo  | Head              | Housing Policy Department  |
|                    |                   |                            |
|                    |                   | Ministry of Urban          |
|                    |                   | Development                |
+--------------------+-------------------+----------------------------+
| Shahinian, Suren   | Academician; VP   | Armenian Engineering       |
|                    |                   | Academy                    |
+--------------------+-------------------+----------------------------+
| Khachian, Edward   | Academician;      | Department of Mechanics    |
|                    | Director          | National Academy of        |
|                    |                   | Sciences                   |
+--------------------+-------------------+----------------------------+
| Melkumyan, Mikayel | Deputy Director   | National Survey for        |
|                    |                   | Seismic Protection         |
+--------------------+-------------------+----------------------------+
| Gohar Hovanissyan  | Leading           | National Survey for        |
|                    | Specialist        | Seismic Protection         |
|                    | Research Assoc.   | Engineering Research       |
|                    |                   | Center American University |
|                    |                   | of Armenia                 |
+--------------------+-------------------+----------------------------+
| Azizian, Krikor    | Chief Engineer    | "Hye Nakhagits" (Armenian  |
|                    |                   | Design/Project) Institute  |
+--------------------+-------------------+----------------------------+
| Miroyan, Hovhannes | Technical Expert  | "Hye Nakhagits"            |
+--------------------+-------------------+----------------------------+
| Shakarian, Albert  | Chief Engineer    | Yerevan "Nakhagits"        |
|                    |                   | (Design/Project) Institute |
+--------------------+-------------------+----------------------------+
|                    |                   |                            |
+--------------------+-------------------+----------------------------+
| **[Shirak Marz     |                   |                            |
| (Province): City   |                   |                            |
| of                 |                   |                            |
| Gyu                |                   |                            |
| mri]{.underline}** |                   |                            |
+--------------------+-------------------+----------------------------+
| Petrosyan, Seyran  | Marzpet (acting)  | Shirak Marz                |
+--------------------+-------------------+----------------------------+
| Simonian, Jora     | Director          | Shirak Urban Development   |
|                    |                   | Department                 |
+--------------------+-------------------+----------------------------+
| Markarian, Albert  | Duputy Director   | Shirak Urban Development   |
|                    |                   | Department                 |
+--------------------+-------------------+----------------------------+
| Aslanian, Gevorg   | Department Head   | Shirak Urban Development   |
|                    |                   | Department                 |
+--------------------+-------------------+----------------------------+
|                    |                   |                            |
+--------------------+-------------------+----------------------------+
| **[Lori Marz       |                   |                            |
| (Province): City   |                   |                            |
| of                 |                   |                            |
| Vanad              |                   |                            |
| zor]{.underline}** |                   |                            |
+--------------------+-------------------+----------------------------+
| Panoyan, Ashot     | Technical Staff   | Lori Marz Construction     |
|                    |                   | Department                 |
+--------------------+-------------------+----------------------------+

+------------------+---------------------+----------------------------+
| **[Donor         |                     |                            |
| Representative   |                     |                            |
| s]{.underline}** |                     |                            |
+------------------+---------------------+----------------------------+
| Vahe             | Tech.               | American Red Cross, Gyumri |
| Khachatouryan    | Delegate/Engineer   |                            |
+------------------+---------------------+----------------------------+
| Eugene Caruso    | Tech.               | American Red Cross,        |
|                  | Delegate/Engineer   | Vanadzor                   |
+------------------+---------------------+----------------------------+
| Levon            | Supervisor/Engineer | American Red Cross,        |
| Yengibaryan      |                     | Vanadzor                   |
+------------------+---------------------+----------------------------+
| Roy Stephen      | Project Manager     | Huntsman                   |
|                  |                     | Corporation/Gyumri Project |
+------------------+---------------------+----------------------------+
|                  |                     |                            |
+------------------+---------------------+----------------------------+
| **[The Urban     |                     |                            |
| Institute        |                     |                            |
| Project          |                     |                            |
| Tea              |                     |                            |
| m]{.underline}** |                     |                            |
+------------------+---------------------+----------------------------+
| Steven Anlian    | Senior Associate    | The Urban Institute        |
|                  | Team Leader         |                            |
|                  |                     | USAID EQZ TA Project       |
+------------------+---------------------+----------------------------+
| Sashur Kalashian | Architect/Planner   | Armenian Design/Project    |
|                  |                     | Institute                  |
+------------------+---------------------+----------------------------+
| Irina Vanyan     | Professor           | Yerevan Architecture and   |
|                  |                     | Construction Institute     |
+------------------+---------------------+----------------------------+

Degenkolb Engineers has extensive experience with seismic resistive
construction and how buildings perform in actual earthquakes.
Degenkolb's engineers have visited numerous earthquake sites and over
the past 50 years documenting performance. Loring Wyllie has visited
many of theses earthquake sites and has extensive experience in
evaluating the potential seismic performance of existing buildings. Mr.
Wyllie is active in code writing organizations establishing seismic
resistive building standards and means of strengthening existing
buildings. A resume is attached.

**The Structural Philosophy of Seismic Strengthening**

Seismic repair and strengthening of buildings that sustain minor to
moderate damage in earthquakes is almost always justifiable in economic
terms. Thus, it is usually always advantageous to repair and strengthen
buildings as a cost-saving approach compared with demolition and new
construction. This is usually the case even when existing building
finishes and fixtures must be removed and replaced to accomplish the
repair and strengthening. I believe this is also the situation in the
Earthquake Zone of Armenia and is confirmed by the recent Urban
Institute report of December 1998. In the Earthquake Zone, vacated
buildings have been looted so there are no finishes or contents to
protect, simplifying the strengthening efforts.

Seismic repair and strengthening of damaged buildings comprises
repairing the obviously damaged areas to return those specific areas to
their pre-earthquake condition and strengthening the structural system
for improved performance in future earthquakes. In the Earthquake Zone,
this includes strengthening the building to a seismic design level twice
as high as originally designed consistent with the new seismic zones and
1998 Building Code of the Republic of Armenia. If masonry buildings are
not somewhat strengthened, structural performance in the next earthquake
will undoubtedly be worse than in 1988 as the masonry may have sustained
many fine micro-cracks that cannot be seen nor repaired and do reduce
the strength. This situation has been observed in several recent
historic earthquakes. Thus, we routinely strengthen earthquake damaged
buildings instead of comprehensive repair to compensate for the micro
cracks and minor damage and original construction deficiencies that
cannot be seen nor readily detected as well as improve performance in
future earthquakes. For example, the reinforced shotcrete added to
masonry walls in Armenia both compensates for any loss of strength due
to microcracks and original construction deficiencies while also adding
additional lateral strength.

Each building to be repaired and strengthened must be addressed as a
unique or individual building complete with an understanding of its
damage state and any modifications to its original plan. While generic
repair and strengthening solutions may be used for the work, that
generic solution must be custom adapted to the specific building with
its unique features and issues. Seismic repair and strengthening
requires experienced engineers to utilize considerable engineering
judgement in determining the appropriate measures for each building.

Foundation strengthening can be very expensive and the adequacy of
foundations must be verified, although most foundations can safely
support small increases in gravity loads due to the added strengthening
elements. Our code for strengthening masonry buildings in California
allows dead loads to be increased over existing loads by 25 percent and
allows dead loads plus live loads plus seismic forces to be increased by
50 percent on existing foundations without foundation strengthening
except at very poor soil sites. From my experience, the "full jacket"
scheme used in Armenia should not require extensive foundation
strengthening.

Finally, I believe it is extremely important the workmanship of the
repairs and strengthening be of the highest quality and be thoroughly
inspected by an inspector independent of the contractor. Furthermore, it
is extremely advantageous in these types of projects that the design
engineer visit the construction site at periodic intervals during the
construction to verify existing conditions and confirm the work is
fulfilling the design intent.

**Armenian Stone Masonry Buildings and Their Seismic Performance**

Stone masonry residential buildings in Armenia follow several designs
for layout and range from 2 to 5 stories in height, although most are 5
stories tall. The older and, I believe, more prevalent style of building
is the stone masonry bearing wall building with precast hollow-core
plank floors and no reinforcing in the walls. These buildings are
generally 5 stories and are long and rectangular being only two bays
deep and many bays long. The buildings have multiple entries with stairs
that serve apartments to either side of the stairway. These buildings do
not perform well in earthquakes and sustained very heavy damage and
collapses in Spitak with moderate damage in Gyumri and Vanadzor. They
are heavy, lack ties and reinforcing, and perform poorly, typical of
unreinforced masonry structures.

A somewhat newer version of these 5-story apartments is a composite
structure of stone masonry and reinforced concrete members. Small
reinforced concrete columns are embedded within the stone masonry at the
wall intersections and longitudinal concrete beams are provided along
the three longitudinal grid lines, which in turn support the hollow-core
concrete floor planks. These longitudinal beams allow wider and more
windows and openings along the long exterior walls and down the middle
of the building. While these beams and columns provide a minimal level
of reinforcing, there is a drastic reduction in the amount of
longitudinal masonry wall, and the masonry is not tied to the frames nor
the floors. Actual earthquake performance again was poor, with many of
these buildings experiencing collapse or severe damage. As these
buildings become longer with multiple entries, the most effective
longitudinal bracing is the end bays where the wall pattern is
longitudinal, but the lack of ties or diaphragm at the end stairways
creates a weakness in transferring forces and was a repeated cause of
damage and distress.

The Soviet-designed stone masonry buildings, of both types described
above, have not performed well in recent earthquakes. The lack of ties
between the walls and the floors, the lack of reinforced floor
diaphragms, and the lack of longitudinal walls in some of the composite
designs has led to severe damage and frequently collapse of these
structures. In addition to the performance in Armenia, the collapse of
similar buildings in Neftegorsk in the 1995 Sakhalin Island earthquake
underscores the vulnerability of these stone masonry buildings.

**Seismic Strengthening Schemes Observed in Armenia**

Before traveling to Armenia, I was provided an English translation of a
"Report on restoration-reinforcing, design and construction work of the
apartment houses, damaged because of the earthquake in the disaster
area," by a Commission established by the Armenia Ministry of Urban
Development. That report provides an excellent summary of restoration
techniques and raises numerous valid and useful suggestions and
directions. However, it seems to lack a frank engineering comparison of
strengthening schemes and their potential performance, which was
probably beyond the scope of the commission's assignment.

This report is limited to strengthening schemes being applied to 3 to 5
story residential buildings of stone masonry construction or composite
stone masonry and concrete construction. These buildings sustained minor
to moderate damage and were vacated after the 1988 earthquake. After
they were vacated, people removed virtually all doors, windows,
fixtures, wood roofs, etc., leaving these buildings as gutted structural
shells.

During my visit to Armenia, I was shown a number of strengthening
schemes prepared by Armenian engineers. We first reviewed a series of
drawings that had been assembled anticipating my visit. We then visited
the earthquake zone on July 28 and saw several strengthening projects in
construction in Gyumri and Vanadzor. We also observed several completed
strengthening projects from the exterior of the building. Although these
strengthening designs were prepared for individual buildings, I have
grouped them into several generic schemes for discussion purposes.

The first and most thorough strengthening scheme design I observed I
will call the "full jacket" scheme. In this scheme, which was applied to
5-story stone masonry bearing wall buildings, the strengthening
consisted of jacketing all interior stone masonry walls with 50 mm of
shotcrete (pneumatically installed concrete) containing steel welded
wire fabric. These concrete jackets were connected to each other on
interior walls with steel ties installed in holes drilled through the
stone masonry at about 600 mm centers. Exterior walls had the jacket
only on the inside face with grouted dowels at 600 mm to the existing
stone and through ties at the floor lines connecting to an exterior
concrete or steel member which was continuous at each floor line. When
needed, some new interior longitudinal shear walls of reinforced
concrete were added (in particular in the composite buildings where
there are few longitudinal walls), and in one design new balconies were
added on one side of the building with a new reinforced concrete shear
wall system framing the balcony openings. Furthermore, all floors were
covered with 50 mm of new concrete containing welded wire fabric and
connected to all the new wall jackets.

This concept of jacketing masonry walls is not a new method for
strengthening unreinforced masonry structures. In the 1930s following
the 1933 Long Beach, California earthquake, engineers in California
developed a method to strengthen unreinforced brick bearing walls by
adding light wire fabric on both sides of the wall with ties through the
wall and cement plaster to encase the wire fabric. This is quite similar
to the wall strengthening in Armenia. Tests were performed in California
at that time which verified the procedure as a valid way to strengthen
unreinforced masonry walls. Variations of this concept are still
currently in use in California.

It is my opinion that this "full jacket" scheme corrects the
demonstrated deficiencies of these buildings, and they should perform
well in future earthquakes. The new wall jackets and floor diaphragms
add considerable strength and ties to all the existing elements. The
exterior elements at each floor tied back to the interior jackets and
diaphragm are extremely important to contain the stone masonry and tie
it into the structure at each level. The added longitudinal concrete
shear walls correct the observed deficiency of a lack of longitudinal
wall in mid sections of some buildings. Buildings properly strengthened
using a "full jacket" philosophy should be well tied together with
considerable lateral force resisting capacity and redundancy not unlike
the precast concrete large panel structures which performed well in
Gyumri and Spitak in the 1988 earthquake. While cracking and some damage
must be expected in future earthquakes, based on my many years of
experience with the actual effects of earthquakes, it is my judgement
that this "full jacket" scheme, properly executed, will provide
life-safety protection to occupants in future earthquakes and be
repairable for future use.

The second scheme I observed, I will call the "corner jacket" scheme.
This scheme adds 50 mm thick or sometimes thicker jackets on interior
walls but only at corners or wall intersections. These corner jackets
extend only 600 mm to 1 meter from the wall corner and contain welded
wire fabric and ties similar to the "full jacket" scheme. The floor
diaphragms are limited to a strip about one meter wide adjacent to all
walls with a nonstructural fill being added in the middle of each bay to
provide a level floor. To increase the longitudinal resistance of these
buildings, new reinforced concrete pilasters or columns were added on
each side of transverse stone walls at the exterior grid lines. These
columns were interconnected with ties through the existing transverse
stone walls with small concrete column and presumably were supposed to
connect to the existing concrete beam on the exterior grid to form a
frame. The connection details I observed in the field did not appear to
positively connect to the concrete beam, so I doubt effective lateral
frame action will be achieved. Some interior reinforced concrete block
masonry walls were also added to strengthen the building longitudinally.
In one design there were some partial exterior concrete beams at the
floor levels although another design did not appear to require those
beams. Masonry being added on the ends of balconies is barely connected
to the structure and does not add any strength.

It is my opinion that this "corner jacket" scheme may provide
life-safety protection to occupants, but these buildings may be
extensively damaged in future earthquakes. The added elements for
longitudinal resistance are minimal and appear to lack adequate
connection to the beams. The lack of exterior beams at the floor lines
reduces the effectiveness of masonry anchorage to the structure, and the
lack of a full floor diaphragm seems like a lost opportunity for
improved seismic performance. The lack of significant floor diaphragm
ties at the stairways fails to transfer forces across these known
weaknesses in the floor diaphragms. This "corner jacket" design appears
to have been developed for selected buildings which sustained minimal
damage in 1988 and to reduce costs from the "full jacket" scheme, but I
believe the actual cost savings may be small when one properly considers
the total costs to make these buildings suitable for occupancy. While
its use may be appropriate for some buildings, I believe this "corner
jacket" scheme is a very minimal strengthening solution which will
somewhat improve the seismic performance over the original design, but
will still be subject to considerable damage. It may provide life-safety
protection to occupants but not with the same assurance as the "full
jacket" scheme.

The third and only other strengthening scheme I was shown was drawings
for a building at 5 Isahkyan Street in Vanadzor. This scheme consisted
of full jackets on all walls in the first floor similar to the "full
jacket" scheme. In the 4 stories above, no jackets were indicated and
the work was limited to drilling inclined holes at 600 mm centers in all
walls and grouting a piece of 12 mm bar or wire in the hole. This work
may not have been executed yet, and we did not visit this site in the
field. This scheme does not particularly strengthen the building except
for the first floor and may create a "hard spot" at the base of the
structure that may cause increased damage above. I have no idea of the
reasons for this scheme as I did not visit the site nor discuss the
design with the designer, but I do not recommend this scheme for general
usage.

The above schemes are generic approaches to strengthening these Armenian
residential buildings. Each building to be repaired and strengthened
must be uniquely studied, evaluated and then strengthened following a
scheme similar to a generic approach. For example, one building we
visited was reduced in height from 5-stories to 4-stories, as the
uppermost floor had more earthquake damage and extreme deterioration due
to weathering after people removed the timber roof to build "domics."
Another building may need unique foundation work in areas where
settlement has occurred.

The engineering designs to strengthen damaged buildings in Armenia
appear to have been performed by experienced engineers using their
judgment. Judgment is necessary for this work as codes and guidelines do
not exist for repair and strengthening. I have based my evaluations and
conclusions on my experience and observations of similar systems
subjected to earthquakes and my understanding of the seismic weaknesses
of these structural systems. For large projects in the future, it may be
appropriate that Armenian engineers prepare design criteria and have it
reviewed and accepted by regulatory officials. Some form of independent
peer review of the designs may also be appropriate.

**Inspection**

A brief but important comment on inspection and construction quality is
appropriate. In the 1988 Armenian earthquake, construction quality
became a major factor with the poor quality of precast concrete
connections being a significant contributor to damage and the collapse
of concrete structures. In the recent site visits to the earthquake
zone, I once again observed construction deficiencies where new bars
passing behind stairs were not concrete encased, new columns were not
well connected to beams, and concrete contained many patches and
appeared to be of low quality. In order for these strengthening designs
to perform as intended, it is essential that the construction be
properly executed.

I was informed and provided translated summaries of several recent
regulations by the Government of Armenia attempting to correct this
situation. An Order #44 of April 28, 1998 and Government Decision #574
of October 1998 appear to give construction inspectors increased
authority and appear to provide governmental review of inspection
activities and construction quality aimed at improving the overall
quality of construction in Armenia. These are certainly appropriate
measures and a step in the correct direction.

However, these regulations will take a long time to properly implement
as most construction workers and inspectors were trained under the
former Soviet system and may not understand what good construction
quality is and how it can be achieved. It will take considerable
training to change these old habits. I'm not sure how that will happen.
One suggestion from our California practice is to require the design
engineer of record to periodically visit the construction site to ensure
that construction quality is being achieved. Inspectors could report
their findings directly to the engineer of record and open
communications between the inspector, engineer of record, and owner or
governmental authority could lead to ensuring the contractor constructs
the work properly.

**Conclusions and Recommendations**

Based on my observations, I have reached the following conclusions and
recommendations regarding the rehabilitation of damaged stone masonry
residential structures in the Earthquake Zone of Armenia:

1.  It is practical to repair and seismically strengthen stone masonry
    buildings in the earthquake zone and such rehabilitation should
    prove more economical than new construction within the region and
    certainly more economical than demolition and new construction on
    the same site. I would note that obtaining accurate and consistent
    information on actual construction costs to make meaningful
    comparisons appears difficult in Armenia.

2.  The "full jacket" scheme to strengthen stone masonry buildings
    appears to provide a rehabilitation that will provide life-safety
    protection to occupants in future earthquakes and result in only
    moderate damage that can be repaired.

3.  The "corner jacket" scheme, which appears to be slightly more
    economical than the "full jacket" scheme, will not perform nearly as
    well as the "full jacket" scheme in future earthquakes, although it
    may provide sufficient life-safety to allow occupants to exit the
    building. Some enhancements to this scheme would greatly improve its
    potential seismic performance, such as stronger lateral ties and
    enhanced longitudinal building strengthening.

4.  Inspection of seismic repair and strengthening projects is extremely
    important to ensure construction quality. Construction quality has
    traditionally been poor in Armenia as well as throughout the former
    Soviet Union. Inspectors (and probably construction workers) need to
    be trained to understand what good quality is and how it can be
    achieved. Reliance on design engineers may be a method to facilitate
    improved construction quality.

**Recommendations for Potential Donors**

Potential donors are foreign governments, foundations, or individuals
who supply financial aid or donations to improve housing in Armenia.
Some of these donors have been reluctant to contribute funds towards the
rehabilitation of damaged structures, preferring to see their funds used
for new construction. Apparently these foreign donors are concerned
about the potential poor performance of these rehabilitated buildings in
future earthquakes and do not wish to be associated with such a
situation.

Recognizing that more people could be returned to acceptable housing in
a shorter period of time if some of these foreign donations could be
used for seismic repair and strengthening of damaged residential
buildings, allow me to offer these suggestions and recommendations:

1.  Donors should be able to designate the degree of strengthening of
    the buildings their funds will be used to rehabilitate. In the case
    of the current schemes being advocated by Armenian engineers, I
    would recommend donors require a strengthening scheme similar to the
    "full jacket" scheme.

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1.  Donors should be able to require a peer review by an independent
    engineering expert of the strengthening designs to verify that they
    will perform well in future earthquakes. Such a peer review, in
    addition to possible initial consultation, could include a brief
    visit to the buildings to observe their general condition and
    construction quality, a review of the calculations or preparation of
    independent calculations for the generic strengthening scheme, and
    discussions with the design engineer relative to the generic scheme
    and design criteria as well as issues regarding the individual
    buildings within the project. The financial contribution would be
    conditional on satisfying the concerns of the peer reviewer and the
    donor.

2.  Donors should be able to require a high degree of quality from the
    contractor and a suitable and meaningful construction inspection
    program. I would suggest that the design engineer coordinate the
    inspection program and make personal periodic visits to the site.
    This would require some additional compensation for the design
    engineer. This need for quality in construction applies equally to
    new construction in Armenia.

**Loring A. Wyllie, Jr. Resume**