Steel is one of the two most important materials in construction in Vietnam today, along with reinforced concrete materials. Especially in recent years, the use of steel has grown rapidly, replacing reinforced concrete (reinforced concrete) in most factories, large span houses and many other public buildings.
Back in history, right from the end of the 19th century to the beginning of the 20th century. All construction works, fabrication technology and construction related to steel are French. Since reinforced concrete has only been applied in Vietnam since the 30s and has almost no large span structures, most industrial buildings and large span constructions such as halls and theaters use steel structures. At least the roof system.
For example, Hanoi Opera House, a famous building completed in the first decade of the 20th century, has its structure built entirely of brick and steel, without reinforced concrete. The round dome is a conical cup consisting of triangular ribs, resting on the rim of the pillow. Low carbon steel, has a strength approximately CCT34 steel. All large floors, balconies, staircases are made of steel beams with a combination of studs, shaped steel beams and rolled tiles to create a floor surface. This steel-beam and brick-roll type floor structure is applied in most floors and is applied in most of the storey buildings that were built at that time.
Significant steel factories are: Gia Lam train factory, Hai Duong winery, airplanes in Gia Lam and Bach Mai … Technology and form of structure are in the contemporary level: low carbon steel, bonded rivets, small rolled steel, classical structural scheme.
Period of the 1950s and 60s: After peace was restored in Indochina, the North of Vietnam began to build a base for industrialization, first of all, heavy industrial plants and light industries. At that time, steel was a rare and very precious material, because it was completely imported from socialist countries, but in these countries, steel was also very precious and rare. The steel structure design motto is: saving at the highest level.
Therefore, steel is only used for large factories, with heavy cranes, high poles and wide spans. Typically the factories of Thai Nguyen Iron and Steel Complex. There, there are all-steel frames with spans of 30 to 40m, hollow pillars supporting 20 to 75 tons of bridge cranes, and 18m-high span crane girders up to 2m high. The amount of steel for a square meter of floor is quite large: 70 to 100kg / m2. Another remarkable project is the Lam Thao Supe Phosphate factory: most of the multi-storey or single-storey workshops use steel structures. Due to the heavy steel usage this factory was completed 1 year faster than using concrete structures.
This has brought great benefits to the industry at that time. Common structural system diagrams are: trusses of angle steels, columns and beams of a combination of plates and rolled steel; welded bond, do not use rivets. In addition, in other cases, only reinforced concrete structures are used: in all civil houses, in most factories, including large span workshops.
For example, at Bach Dang Shipyard, the 21-meter-wide workshop used pre-stressed reinforced concrete, which weighs more than 10 tons, is extremely difficult to construct while a similar steel frame weighs only 1.5. tons but not used. In many other cases, to support the 100kg cement fibrinolytic panels, we used concrete purlins weighing up to 500kg, but did not dare to use a gentle steel purl. These examples clearly demonstrate the policy of not using steel structures whenever possible …
Periods of the 70s and 80s: Construction work is mainly about restoring damaged structures, building new light machines. Mixed structural scheme is widely applied: concrete columns and steel trusses. Started using many pre-engineered steel structures imported from abroad.
Typically, the Tiep warehouse frame type, which is a span of 12 to 15m, is made of steel pipes, combined steel columns and purlins are cold-rolled thin-walled components. This frame was originally used as a lawn warehouse. In Vietnam, it was renovated to serve as a structure for workshops with skylights and cranes, sports houses, and even an airport terminal. In addition, many civil works such as schools, hospitals supported by humanitarian organizations imported from abroad, are made of pre-engineered steel structures with 1 floor and 2 floors. The steel-saving motto is no longer strong; factors for ease of transport, construction, and quick completion have become decisive.
In the South of Vietnam during those periods, construction techniques were developed rapidly with the support of technologies from advanced countries.
The design trends are the same as those of the West: steel is widely applied in industrial buildings, shipyards, high-rise buildings (up to 16 floors), airplanes and multi-storey apartment buildings.
The 90s to present: Along with the rapid development of the economy and the construction industry, the use of steel has increased unprecedentedly. Almost 100% of factories are made entirely or mostly of steel structure. The heavy reinforced concrete roofs have disappeared, replaced by light corrugated iron roofs placed on thin-wall purlins. Nowhere to see the reinforced concrete staging, prefabricated reinforced concrete roof beams have been developed for a while.
In the industrial sector, steel structures are used for industrial factory frames, conveyors, machine bases and mechanical details …
In civil engineering, steel structures are widely used in purlins in the past and today, along with the development of software and the skills of Vietnamese engineers, steel structures have been used for structures. office structure, high-rise buildings from 10-20 floors.
Hanoi Museum Building, built to commemorate 1000 years of Thang Long in 2010, the work has an inverted pyramid structure, of which the 4th floor has the largest area, the lower floors are smaller. Design consulting firm GMP – ILAG (Germany). Built on a total area of about 54,000 m2, 30.7m high. The project includes 4 floors and 2 basements.
JW Marriott Hotel is also a unique steel structure in the heart of Hanoi. Designed by famous architect Carlos Zapata J.W Marriott with a very impressive design based on the idea of a poetic Vietnamese coast, inspired by the image of “legendary dragon”. The hotel is structured in a spiral curve, 9 floors, with 450 rooms, facing the lake surface, signifying the flourishing before the open sky, combined with the green inner garden of nature has created an elegant appearance.
With the advantage of fast construction and exceeding a large aperture of up to 100m, the steel structure is also widely used in trade centers, supermarkets and show rooms.
There are many advantages as well as the importance of steel structure to the needs of human life today. Minh Danh will be mentioned in the next articles.