In 2015, a merge of three previously existing departments took place: department of Metal Structures and Test Structures, Department of Reinforced Concrete Structures and Department of Timber and plastic Structures were amalgamated into one joint department of Construction Structures.
The main direction of scientific activity of the department is the improvement of calculation methods and the study of new types of building structures.
Substantial attention at the department is paid to experimental and theoretical studies of spatial structures. Extensive work is carried out aimed at the development and refinement of calculation methods for long cylindrical shells, cooling towers in the form of a single-cavity hyperboloid of revolution, hyperbolic paraboloid-type shells and Ferro-cement shells.
Theoretical studies were followed by experiments on large-scale models or samples in full size (2000). As a result of these works, recommendations were published on the calculation of ordinary and pre-stressed cylindrical shells for symmetrical and one-sided loads, on the calculation of chimney-type cooling towers and shells of negative Gaussian curvature.
A number of scientific researches of the department are related to the study of the stress state of bending elements of light and cellular constructional concretes. In 1970, under the leadership of G. N. Sorshnev the research of reinforced concrete high-pressure vessels for nuclear reactors and other purposes were launched. A new type of reinforced concrete for pressure vessels and other structures was developed; conditionally it was named heavy reinforcing cement. This work had a complex character, i.e., constructive solutions, special compositions of reinforced concrete, calculation methods, and construction technology for building structures was developed; in addition, extensive experimental research on fragments and large-scale models was conducted. Further on, research in this scientific area was expanded. Original design solutions of high-pressure heat accumulators for new generation of power plants and autoclaves for construction and special technologies had been developed. The research of these structures was reflected in the doctoral dissertation of Professor V.I. Morozov (1994).
An essential area of scientific research of the department is reinforced concrete structures strengthened with steel fiber. Dispersed concrete reinforcement is able to improve mechanical characteristics of the material: increase strength, ultimate compressibility, fracture toughness, impact resistance, etc. The department holds active research in the field of high-strength fiber-reinforced concrete and the efficient use of high-strength reinforcement. For the development of the theory, the creation of technologies and the progress in the mass production of effective structures from fiber concrete, the team of authors led by the head of Department V. I. Morozov in 2007 was awarded the Prize of the Government of the Russian Federation in the field of science and technology.
The systematic study of building metal structures began back in 1928, when a new discipline "Metal Structures" was introduced into the curriculum. In the same year, a department of Metal Structures and Testing of Structures was founded. It was the first department of that kind in the Soviet Union. Later on, other specialized colleges of the country established similar departments. The head of the LISI department was Honored Scientist of the RSFSR, Professor N. N. Aistov, Dr. of Engineering.
Presently, the Department has a mechanical laboratory named after Professor N. N. Aistov. The laboratory was founded in 1900 and has its own unique history. Existing upgraded testing equipment allows studying not only models, but also life-size constructions. In 2014–2016, the modernization of the mechanical laboratory has been accomplished.
In 1930, a new Department of Wooden Structures was organized. Its first head was its founder, professor Vladimir F. Ivanov (1880–1965), Dr. of Engineering, honored worker of science and technology of the RSFSR. Earlier, he had worked with P. I. Dmitriev in the field of building statics and wrote the first in our country textbook on the subject, Timber Structures of Civil Buildings (1927). In 1932, the second part of this the textbook covered issues of both design and construction with the use of timber of a wide range of structures. During the period of the 1920-1930s, with the participation of the staff of the department (first three, then four people), engineering structures made of timber were developed and under supervision of the authors built in Leningrad, Artyomovsk, Arkhangelsk, Murmansk, Rostov, Kharkov and other cities.
The department paid great attention to the issues of behavior during operation and durability of wooden structures, as well as to the study of conditions providing for the increase in their service life. During the Great Patriotic War, a lot of work has been done in relation with the restoration, strengthening and bringing into operation of many industrial and civil facilities.
Then postgraduate student E.N. Kvasnikov dealt with issues of long-term strength of timber since 1938. For its time, it was quite well-equipped. Later, professor E. N. Kvasnikov, Dr. of Engineering, became the head of the department and rector of the institute, then named Leningrad Civil Engineering Institute.
In 1949, E.I. Svetozarova joined the Department of Wooden Structures. She successfully engaged in the introduction in the construction of glulam beams. She has designed enveloped structures with the use of plywood shells of double curvature, i.e., barrel vaults and dome coverings, as well as frame designs that are frequently used in agricultural construction. She brought together a group of scientists, which included E. N. Serov, V. Ya. Terentyev, V.D. Popov, E. A. Shmakov and others, which conducted research for Agriculture R&D Institute (GiproNIIselkhoz) and other organizations.
Since 1951, S. A. Dushechkin conducted work on the creation of new types of structures (trusses, frames, arches) using plywood and plywood sections with the development of new types of nodal joints (factory-built and for installation), and also created a group of structural tests that conducted a large number of field tests. For this purpose, one of the premises of the department was equipped with a “power floor”. They were made and tested by trimming the farm from plywood pipes with a span of 12, 18 and 24 m, with cuttings from plywood and wood-laminated plastic DSP-V and nodal bonds (dowels and bolts) from wood-laminated plastic DSP-B and fiberglass AG-4 and SWAM.
In the 1960s and early 1970s, then postgraduate student of the department L. Ya. Kupche explored new types of plywood with predetermined strength and elastic characteristics. Professor E. N. Serov, based on his work in the field of glulam timber, developed the basics of the rational design of glued wooden structures, linking wood anisotropy with the possibility of the use of strength properties during their construction. These ideas were applied in practical works related to the introduction of glulam-wood and glulam-veneer frames in the practice of construction. Professor G. G. Nikitin proposed a calculation method for nugget joints based on the consideration of the dower nest as an elastic-hereditary medium, as well as dowers made from wood-laminated plastics and fiberglass.
Increased production of polymer materials and the expansion of their application made their use in building structures rather promising. The name of the department was changed and it became known as the department of Timber and Plastic Structures. In 1965, Professor G. G. Nikitin headed a group for the development and introduction of translucent structures in construction practice (L. P. Karateyev, V. I. Smirnov, A. V. Rezunkov, L. V. Panchenko). Translucent structures have been developed for the North-West and Far North (domes, panel lights) along with the manufacturing technology and algorithm of calculations.
A major contribution to the development of plastic structures was made by the Assistant Professor of the department, Yu. D. Sannikov. He found the absorption coefficients of various fiberglass with free vibrations. He did this applying non-destructive methods for determination of physical and mechanical properties with the use of ultrasound. Since the early 1960s, properties of plastics were studied by postgraduate students, employees of the department and its laboratory, including G. M. Savitsky, Yu. E. Khangu, A. I. Potapov, G. M. Dolganov, O. O. Karapetyan, V. I. Volkov, E. I. Kogel, etc.
Employees of the department are actively engaged in bettering the regulatory standards on the design of structural timber. E. I. Svetozarova and E. N. Serov are the co-authors of the “Guide for the design of glued wooden structures” (1977), “Manuals on the design of wooden structures (for the SNiP II-25-80, E. N. Serov developed proposals which were included in the Code of Rules 13330.2011 “Timber structures" and "Technical code of established practice. Timber structures. Building design standards” of the Ministry of Architecture and Construction of the Republic of Belarus (Minsk, 2009)).
New designs and methods for their manufacture were repeatedly exhibited at the Exhibition of Economic Achievements of the USSR, awarded with Diplomas of Honor, silver and bronze medals. The textbook authored by E. N. Serov, Yu. D. Sannikov, A. E. Serov “Design of wooden structures” published in 2011 (M., SPb: ASV, 2011 (Kurgan). - 534 p.) was awarded a diploma as the best textbook for higher school.