This external wall with face brick connected in bolt-type and steel-bar-type pertains to the construction industry, including two parts: civil engineering and external decoration.
In modern buildings, insulation of external wall has been increasingly emphasized and plays an important role in energy conservation. The traditional single-wall structure cannot meet higher requirements of insulation even if its thickness is increased to 70 cm. Most modern buildings do not support such thickness for reasons of the weight and material. With the production of mineral fiber and glass fiber etc., 10 cm thick of these insulation fiber can bring a thermal performance much better than the thick traditional wall. However, the technique for combinations of the insulation layer and double wythes of external wall is far from being perfect, various insulating materials have been installed onto the outer face of external wall in precarious ways, and a protective layer is further added onto the insulation materials, which brings concern to their strength and durability.
At the same time, modern building's curtain walls of glass, stone, metal etc. have formed a unique style. With prevailing use of this style, the traditional brick facades begin to gain consideration again, so as to form a reasonable proportion of curtain walls and brick walls, avoiding monotonous visual effects.
Under these circumstances, the Curtain Wall Brick (also called Face Brick) came into being. It is hollow and lighter than ordinary brick but with the same material and appearance, being produced by more and more manufacturing plants. It has a certain bearing strength, but its main purpose is to bring the real effects of brick, and it needs to be securely combined to the main wall which can be made of light concrete block. For its connection to the main wall, there is still no standard domestically and abroad, and no convenient way has been found. Production of the traditional solid bricks has been stopped due to their tremendous consumption of material and huge weight. In place of the solid brick is the light concrete block, which is big and light to save time of construction. But its surface is rough, needing a decorative face. Various brick-like tiles have been produced as the decorative face and are stuck to the main wall. But they cannot bring the real effects and may fall off, bringing a potential danger. Many construction codes have prohibited their use in middle and high-rise buildings.
To enhance the connection strength of the face brick to the main wall so as to prevent the face brick from collapsing or falling off in an earthquake or other impacts, it is necessary to combine the face brick to the concrete block in such a way that insulating materials can be filled between them and they can reach the needed solidity and durability. With the methods of combination which bury cross steel bars in the horizontal joints of both the concrete blocks and the face bricks, the heights of the combining joints need to be put at the same level, which is not easy to be done, because a normal-size concrete block is much bigger than a face brick, and dimension of the concrete block is not easy to be kept accurate. Moreover, in large-scale construction, laying of concrete blocks is done during the civil engineering phase, laying of face brick is done in a later phase. As they are not done at the same time, for their connection, pre-embedded connectors need to be installed during the first phase. However, if a small inaccuracy is made with height of the horizontal joints, it will bring great difficulties for aligning the heights to the same level when laying of face bricks is being done later, which will make the pre-embedded connectors unable to be properly buried in the joints of face brick, and will not be able to guarantee their strength and appearance. These problems need to be solved.
As per the solution in
When the face brick is connected to the main wall through this way of using bolt, the connectors and construction are simplified. The connectors can be pre-embedded and freely adjusted for heights while the connecting strength is maximized (because the face brick is connected by the buried member in its joint, however strong other connecting members are, this weakest link is the strongest for the whole connection).
The above solution can be called the Bolt-type Connection. With this connection bolts are to be used and for each square meter of wall around 2 are needed. Although their cost is much lower than curtain walls, yet if merely steel bars are used for connection, the cost can be further reduced without lowering the strength. As described above, if just steel bars are used for connection, the height of face brick joint need to be put at the same level as that of the concrete block. But normal-size concrete block is much bigger than face brick. To solve this problem, it's needed to custom-make concrete block for a certain height according to height of face brick, or custom-make face brick according to concrete block, or custom-make both of them. The ultimate purpose is to make the height of a number of face bricks plus their joints be the same as that of a number of concrete blocks plus their joints, which algebraic expression is as follows:
(a+m1)x=(b+m2)y
In the equation a is height of concrete block, b is height of face brick; m1 is thickness of mortar in concrete block joint, m2 is thickness of mortar in face brick joint, x and y are numbers of layer for the concrete block and face brick respectively.
This way of connection can be called the Steel-Bar-type Connection. As one of its cases, in drawing 2 the two layers of face brick 1 plus the two layers of mortar 4 have the same height as the one layer of concrete block 2 plus one layer of mortar 5. In this manner, provided a number of face brick 1 plus mortar 4 have the same height as another number of concrete block 2 plus mortar 5, the connection can be done. However, it shall be guaranteed that for every 50 cm (reference value) of height in the most, the same height of joints occur in both wythes. In
The steel-bar-type connection needs accurate control of heights to satisfy the above equation, thus the same-height-joints will occur in succession and the steel bars can be buried smoothly. If construction of the concrete blocks is not done simultaneously with that of the face bricks, deviation with heights can easily take place to bring difficulty for later construction. Usually civil engineering and external decoration are not done at the same time. For simultaneous construction, the work of external wall in civil engineering need to be postponed to the time of external decoration.
In conclusion, the bolt-type connection is simpler but with a higher cost than the other type. The steel-bar-type connection is cheaper but with comparatively more complicated construction than the former. Which option to take shall depend on the specific projects.
The above bolt-type and steel-bar-type connections can make the face brick and the concrete block connected in a fine way, greatly simplifying the connection and making the construction cost much lower than traditional curtain walls. Thus they have a good expectation for wide use in mid-rise and lower buildings, attaining ideal thermal insulation, bringing visual effects to be combined with curtain walls of various materials, and saving cost, energy, labor for the national economic development. At the same time, they can help promotion of the development in building styles and structural types.
1) Connection
With both the bolt-type and steel-bar-type connections, rustable steel or iron products need to be galvanized. Diameter of steel bars and their distance to each other shall guarantee that in earthquake enough tensile resistance and compressive resistance be provided by them. According to thickness of joints between the bricks, diameter of the steel bars can be as thick as possible with enough mortar above and under them. The horizontal distance between two steel bar connectors can be around 50 cm (reference value. In practice it shall be based on structural calculations).
With the bolt-type connection, as in
With the steel-bar-type connection, as in
In the two types of connection above, the bolt can have various shapes and may not necessarily have screw on it; the nut can be replaced by a pin or other obstacles that can prevent the steel bars from slipping out of the bolt; the X-shaped bars, I-shaped bars, and square bar can be cast products or other metal products. Whatever shape and material, the principles and modes will be the same.
2) Insulation
For buildings with higher insulation requirements, an insulation layer ought to be put between the face brick and concrete block. As there are connectors of bolt or steel bar between the two wythes, loose insulation fiber may be easier to install; If insulation sheets are to be used, slits can be made at positions of the connectors.
The distance between face brick and concrete block need to be as near as possible to save space as well as the amount of steel bars and insulation fiber. However, if the concrete block and face brick themselves cannot provide enough function of insulation, the distance between them needs be increased, so does the amount of insulation fiber.
3) Service Life
The appearance of brick wall will not be affected much by time, and may even look more charming with age (the bricks of the Great Wall still do not look old today). If qualified inorganic insulation fiber is used and the steel bars and bolts are hot-galvanized properly, then the above external wall of face brick can last at least 100 years. If the cavity between the face brick and the concrete block is sealed with sealant (but drainage holes ought to be set at the bottom in case water enters the cavity), at the same time, a suitable amount of calcined lime is put in the cavity (which can absorb excessive moisture in the air left in the early stage), and moisture filtering materials are put at the drainage and air-flowing holes (which can prevent moisture but allow an amount of air to flow due to change of temperature), then all the functions of the external wall can be protected better and the service life can be prolonged. If conditions are ready for using stainless steel instead of the above galvanized steel bar and bolt, the service life may be regarded as permanent.
4) Safety Inspection
During the process of laying concrete blocks, at the bottom of each wall a gap can be reserved for installation of the drainage and inspection hole. As
Conditions of the steel bars, bolts, insulation fibers, etc. need to be inspected periodically, so that an accurate assessment can be made on the whole external wall.
type implement methods here.
For energy-saving, this face brick external wall has two wythes plus an insulating layer, and thickness of the insulating layer can be freely set. Hence it can satisfy the highest requirement for thermal insulation in all areas, and save a huge amount of energy for temperature control of houses. Compared to the current curtain walls that have not good performance in thermal insulation, this face brick external wall can improve the insulating performance for more than 10 times; Compared to concrete wall or brick wall, its insulating performance can also be times higher.
For appearance of buildings, this face brick external wall has a particular primitive style, and its hollow face brick can make a more natural effect than decorative tiles. This style plays an irreplaceable role in the planning of urban and suburban development, and is able to bring abundant visual effects. However, now its proportion is extremely low, forming a vacancy for development. In architectural planning and design, its models and renderings can express most of the real effects, making an advantage in bidding of related projects.
In terms of construction cost, this face brick external wall's how brick, concrete block, and insulating sheet are each just dozens CNY per square meter; the connectors of a bolt or two and steel bars for each square meter also cost very low. In comparison to curtain walls that need hundreds or more than a thousand CNY for a square meter to be built, this face brick external wall's cost is many times lower.
For construction, the techniques for this face brick external wall are not complicated. Across the country there are still many technicians with good command of brick laying. Training for people is also not difficult.
In conclusion, application and promotion of this face brick external wall can bring a big economic benefit and long term comprehensive benefits for architectural units, urban and suburban planning units, construction units, real estate development companies, and the vast number of users.
type content of the sequence table here.
Number | Date | Country | Kind |
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201510155539.9 | Apr 2015 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2016/076718 | 3/18/2016 | WO | 00 |