PostHeaderIcon Malkhaz Bediashvili: "THE ROLE OF EXPERT EXAMINATION OF CONSTRUCTION PROJECTS FOR THE INCREASE IN CONSTRUCTION SEISMIC STABILITY"

Malkhaz Bediashvili - Academician of Georgian Engineering Academy, European Union expert in the field of constructions, honored constructor of Georgia

At present, Georgia is undergoing a real building boom, many-stored dwelling and public projects are under construction, including 40-storey buildings unusual for Tbilisi. Tbilisi and Batumi international airports, 25-storey “Sheraton”- class hotel in Batumi, trunk-lines and Baku-Poti, Kulevani oil-pipelines, etc. have been and are being built.

The century projects are already built  Trinity Cathedral in Tbilisi, cathedral to be built in Zugdidi and many others.

Main requirements for these projects are their stability and seismic stability in high-intensity seismic activity regions, namely in the regions with the magnitude of 8.

 

In these conditions especially high requirements are imposed upon expert examination of construction projects.

In Georgia, after destruction of the acting expert examination system, the Government developed and put into effect from 1st January 2007 the “Preliminary Procedure of Necessary Expert Examination of Construction Projects of Special Importance” according to which parts of the projects to be subject to examination are:

a)     Engineering geology and engineering hydrogeology;

b)    Bases and foundations;

c)    Main supporting building structures.

At the same time, after acceptance of the “Expert Opinion” by the customer, the “Final Expert Opinion” is given only with allowance for remarks and corrections which must unambiguously be positive or negative and on  the basis of which a building permission is issued.

The list of especially important projects subject to expert examination has also been approved.

These are: Airports and sea ports, main oil-or gas-pipelines, industrial projects with dangerous industrial projects with dangerous industrial processes, more than 10-storey buildings as well as buildings-constructions of more than 20 000m3 volume, open sporting buildings-constructions for more than 10 000 seats, etc.

The body authorized to issue building permissions gives the expert or the expert organization the project documentation to make an expert examination only after a comprehensive check of the expert personality.

Below, some examples of the considered results of my examination are given:

  1. The importance of  “Trinity Cathedral” for development of spirituality of the Georgian nation is well-known.

Therefore, the project documentation which was initially represented in the form of 45 albums ( author team leaders, architects A. Mindiashvili and engineer E. Kiziria) was subject to comprehensive expert examination.

The construction project was checked step-by-step for: separately plot of land, land surface and dome.

The remarks and proposals were considered and taken into account at the working stage of the project.

Special attention was given to the problems of static and dynamic calculations of the cathedral, to foundation plates which involved 3600m3 of concrete, concreting technological problems: protection against plate satisfaction, cracking and loss of supporting power in hot, rainy, windy and cold conditions; landslide problems, etc.

The problems of highest-level acoustics, illumination, ventilation and air exchange in the cathedral were solved.

At present, the cathedral has been built and is sure to serve people for centuries.

  1. The history of building and designing Tbilisi International Airport is probably well-known far beyond Georgia.

When the project was submitted to expert examination, the building permission, as we were said, had already been issued and our expert examination was only of formal character.

However, the opposite situation was observed: the expertise examination showed that this air gate of great importance was designed with big mistakes:

a)     Wind load was considered 2,5 times less than required.

b)    Foundations were based on soft flaky grounds and the results of engineering-geological survey were not taken into account;

c)     And finally, seismic action was not taken into consideration.

To the credit of the Turkish designers, it should be said that for three months they managed to make building re-calculation based on real situation: wind and seismic activity.

The project solution for foundation bases was checked and, what is the most important, the airport configuration was changed.

Today, it can be easily stated that the building structure, its supporting structural elements will be stable for centuries.

As for the boom raised by journalists, about rain water leakage from the roof,  it concerned essentially the poor quality material for corrugated elements of the roof construction, which became already a commercial problem.

  1. At present, the expert examination was made for the highest building in Tbilisi “ Business centre on Chavchavadze Avenue”  It’s foundation bases and structural parts were studied.

This actually a 40-storey building, consists of two blocks and looks very attractive.

At the design stage the developer company “Axis” studied the experience of foreign countries, their norms and codes. The calculation was made using three component synthetic accelerograms adopted after processing the data of the earthquake took place in Tbilisi on 25th of April, 2002.

Experts remarks referred to the increase in rigidity of the supporting cores, temporary building proof load value, concrete and concreting technological problems, use of sliding forms during erection of  rigidity cores, to the problems of drainage equipment while making the 4th underground floor, building plan with allowance for twisting of columns in the corners, special suspension clips, etc.

  1. Expert examination was completed for complicated building by German architect Jürgen Mayer and Georgian civil engineer in Sarpi. His “custom control office”, constructed as 40-meter-tall steel structure having 14-meter-long cantilevers.

This project is winner of competition held by Ministry of Economy and Sustainable Development.

It should be added to the above that all important industrial constructions are subject to expert examination: concrete production, metallurgical, trunk-line, oil-pipeline and other projects.

The expert examination made at the design stage increases significantly the guarantees of building and construction seismic stability.

Therefore, “Georgian Building Expert Association” [(GBEA) (“MESA” in Geo) ] has been established.  It is an independent association of highly skilled  experts whose goal is to improve the reliability of buildings and constructions, to provide a governmental approach to the results of expert examination, to give consultations, etc.

“GBEA” involves European Union experts in the field of architecture, construction, geology; their specialists gained experience in making expert examination in different countries, including Japan, Great Britain and etc.

The expert examination presence isn’t required for less significant buildings (for e.g. cottages, less than 10-storey living blocks, commercial buildings and etc.) to get construction permission. In this case expert examination can be performed according to client’s desire, but expert examination is linked to some expenses and clients very often try to avoid it. This is a mistake from their side. The mistakes in design could be a reason of not only poor stability, but non-economic usage of materials and increase in costs. The mistakes in design (as a result of non-competent designers or very quick working) can cause much more expenses than the cost of expert examination.

It should be emphasized that a qualified expert examination will raise significantly seismic stability and reliability of constructions and expectation of expert examination will increase attention from project designers to technical and economic parameters of buildings.