In-Depth: Plywood Construction
Israel. The main road of the country is the Tel Aviv - Ashdod. Construction of Sayarim Bridge, which will connect the road to the city of Holon is being carried out. In the heat from construction the bridge has started to collapse, and the constructers have had to disassemble a length of 70m and build it again.
After an investigation it was found that the collapse occurred because the constructer had used poor quality laminated plywood, which it had bought from a Chinese supplier. Possessing poor physiomechanical properties, the poplar laminated plywood, had absorbed moisture and expanded, causing sagging and breaking the geometry of the design, leading to a significant decrease in the durability of concrete. When the concrete dried there was a loss of bearing ability to one of the bridge spans.
Such problems are not new to Russia. The growing volume of consumption by Russian builders of production whose quality is unchecked is forcing us reflect on the destiny of premises under construction: housing, social and commercial real estate. Every year 30-40 buildings and other structures collapse in Russia. The tragedy at Transvaal-Park in 2004 took the lives of 28 people. In 2006 the roof of Basmannaya market caved in, killing 64 people. The main reason for the majority of the tragedies is infringement of construction rules and technologies and poor quality building materials.
The question of the quality of a building has become especially current. The annual increase in the volume of housing construction in Russia in the last five years has been 12-13%. In 2007, according to Rosstata, there has been almost 20% growth. In 2007 a transition from the use of large-panel housing construction technology to technologies of frame and composite housing construction as a more economic and flexible variant of construction for more accessible habitation took place. Now 77% new buildings in the largest regions of Russia have composite-frame design and so are under construction with the use of laminated plywood for timbering.
In the next few years in Russia several large projects will be started. The most significant of them will be realized in Sochi under a national program worth $12 billion, which will include the construction of sports premises for the 2014 Olympic Games. With the construction of such premises the level of responsibility of builders increases.
Russia has a huge quantity of wood resources and annually produces more than 2.5 million cubic meters plywood. But this seems insufficient. Russian production meets European and American standards, and has the necessary international certificates on emissions of formaldehyde and sanitary-and-epidemiologic conclusions, which is why the best grades are exported. For own needs we get what’s left of our own production and production from abroad –which is of unknown quality. In 2007 compared with 2006 there was a 6-times increase in imports of plywood to Russia - mainly Chinese plywood: supplies to Russia have increased more than 11 times. The absence of quality assurance of production imported into Russia has led to the absence of guarantees for end users. Russian builders buy what is offered at a market, not caring about the quality of the executed work or health and safety of those who will live in the new buildings.
Both suppliers and buildings know about the dangers of using poor-quality plywood. Such plywood is made not from whole sheets, but from lumpy veneer sheets, i.e. they possess bad physio-mechanical characteristics. It is a significant defect for plywood and excludes the possibility of its use in composite construction as such construction means the skeleton of the future building is formed from it. Poor-quality plywood also has non-uniform thickness, many stratifications, bad geometry, friability, and, most importantly, it emits a high level of formaldehyde causing damage to the environment and the health of people. Such production is most often brought into Russia from China - suppliers show counterfeit certificates and illegally put the trade mark of the Wood Association, which guarantees certification of the chain of deliveries from the supplier to the end user of finished goods.
It is necessary to note that developed countries actively develop a program for quality checking building materials. In America and Europe only production from known world manufacturers is used for the construction of public and socially significant constructions. The government of the UK has announced that all sports premises for the Olympics 2012 in London will constructed only with certificated raw material. The senate of the USA in 2007 legislatively introduced restrictions on the class of issue of formaldehyde for production (plywood) imported into California. EU countries are considering the possibility of introducing additional antidumping duties on production from China. Unfortunately, in Russia there are no legislative restrictions against the importation of poor-quality building materials, and we need to hope that builders use their consciousness and social responsibility when choosing building materials.
Andrei Gusakov, director for construction at Komstrin says: "Complaints concerning poor quality Chinese building materials should more than likely be directed at Russian suppliers of these materials. Everywhere people complain about poor quality Chinese glass, aluminium, metal rolling, cement, lifts, etc. But in China construction is carried out only with the use of locally manufactured materials. Even Shindler lifts and these are Made in China.
The volume and quality of construction in China, unfortunately, is much higher than in Russia. But supplies of goods to Russia are mostly back yard production bought from flea markets and carried in bags. High quality production costs money, including in China."