Russian Association for Shock-resistant Construction and Protection against Natural and Technological Impact - RASC
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Build. 6/37, Institutskaya 2, Moscow, 109428 tel/fax (095) 174-70-64, 174-70-21
Conclusion
on structural reliability of multi-storey buildings of combined system
(proposal of "IICC Group" International Association)
in case of impacts of earthquakes, wind and explosion loading
The structural system under consideration is designed as an alternative for designing and construction in two directions:
* in large-scale development by buildings with various number of storeys, including those meeting the scope of 17-25 storeys;
* in development of the so-called "high-rise areas", where 30-45-storey buildings are to be applied.
* according to the submitted project, the specificity of the architectural-and-planning concept of the proposed system ensures extension of access of much more apartments to the stairwell and elevator as compared to the number of apartments in the traditional, currently used concepts. This results in enlargement of the effective area alongside with maintenance of the amplified comfort. The possibility to achieve optimal expansion of the residential area, to increase the development density, to free space for building of new low-rise sports, entertaining, educational, trade, welfare facilities in it is demonstrated by the example of 2 micro-districts of Balashikh town in Moscow Region, as well as by the example of Odintsovo district in Moscow Region. These examples have revealed the economic, planning and architectural-and-functional dignities of the proposed system. The results were approved by the State Unitary Enterprise "Research and Design Institute of General Plan of Moscow".
* the specificity of the structural concept of the supporting construction of the proposed buildings is application of a dual supporting system with clear and distinct division of the supporting sub-constructions meant for bearing of:
1. Vertical loading (dead loads, running loads, dynamic impact of earthquakes and explosions);
2. Horizontal loadings (seismic and wind loads, as well as impacts of explosions, etc.). Vertical loadings are mostly carried by a set of one-piece reinforced concrete columns. Horizontal loadings are carried by a spatial system of one-piece reinforced concrete walls. Both of these substructures are connected by hard one-piece disks of covering ensuring the joint activities of both substructures.
The most important peculiarity of this dual system from the viewpoint of seismic reliability is the much higher hardness of the walls and diaphragm plates in horizontal direction as compared to the hardness of columns, as well as the high durability and hardness of columns in vertical direction. This peculiarity ensures high reliability of the system in case of strong seismic loads, as well as in case of explosions, for instance, during the acts of terrorism and strong wind impacts. The methodology of the use of this feature for optimal designing is the intellectual property of the staff.
Therefore, to observe the privacy of information about the copyright holders' know-how, which is the proposed structural system, this conclusion provides no detailed description of these characteristic features of the system and its component - the vertical spatial supporting construction. For this reason the behavior peculiarities and advantages of the New universal construction and planning structure being a summary of new types of multi-storey buildings of the proposed combined structural system are not considered in detail either.
Notwithstanding this, the examination of the submitted materials is sufficient to make a conclusion about the novelty of the "IICC Group" Association's proposal, as well as about the high reliability of buildings of the proposed structural system and their efficiency in construction in common and seismic conditions.
Certain experience of use of similar structural systems and their behavior in case of quite intensive earthquakes is available. One can refer to the behavior of similar types of buildings during the earthquakes in Santa Cruz (San Francisco, California) in 1989, in Gyumri (former Leninakan) during Spitak earthquake on 7 December 1988, in Northridge (near Los Angeles, California) in 1994. The buildings of the proposed system can also be effectively used to ensure reliability and safety of population in the areas where high wind loads up to 85 kg/m2 are forecasted and explosion loads are possible. The systems are stable and durable under conditions of progressive fractures in case of shutdown of certain building elements.
- On the whole, the buildings of the combined structural system under consideration may be recommending for large-scale introduction in both proposed directions, i.e. in construction of multi-storey buildings in new micro-districts of affordable housing, and in construction of free standing high-rise buildings.
Conclusions
1. The new combined system variant admitted to examination includes a dual seismic protection system, which allows ensuring high seismic reliability of the buildings in case of strong earthquakes, as well as explosion and hurricane loads.
2. The dual seismic protection system allows additionally using the innovative seismic protection technologies, e.g. seismic isolation and damping. This may essentially improve the economic indices and enhance the reliability of buildings in case of intensive earthquake attacks, explosions, as well as survivability in case of progressive fracture and, consequently, the security of the population.
3. The consideration of the issues of reliability of multi-storey buildings and seismic safety, particularly, in connection with the proposed combined structural system, is topical, since about 30% of territories of the Russian Federation are earthquake generating regions. Construction of multi-storey and high-rise buildings is set in these regions for a number of reasons: economic, architectural, etc., for instance, in Sochi, where the winter Olympic Games of 2014 will take place and a project of large-scale construction of multi-storey buildings is set; Petropavlovsk-Kamchatsky, Irkutsk, etc. In addition, as a consequence of man-made activities (rise of the ground water line and other impacts), seismic hazard arises in the towns, which were formerly considered being unhazardous. The same concerns other territories. These circumstances draw attention to the seismic safety and the safety in case of other dynamic impacts.
4. Over the period before large-scale launch of the buildings of the proposed combined structural system, it is recommending to grant a relevant patent to the know-how of the copyright holder as results of the intellectual activities of "IICC Group" Association, taking into account its unconditional novelty. In this case, the above-mentioned issue of the intellectual property privacy will be taken off the table and will not hinder large-scale launch of buildings of the structural system.
Professor Ya.M.Ayzenberg,
Doctor of Engineering,
Honorary Academician of Russian Academy of Architecture and Construction Sciences,
Honored science worker of the Russian Federation,
President of Russian Association for Shock-resistant Construction,
Head of Seismic Resistance Laboratory of
Central Scientific Research Institute for Building Constructions of
Federal State Unitary Enterprise "Construction Research Center"