Thursday, April 30, 2020

NEW APPLICATION AREAS OF SFRC

NEW APPLICATION AREAS OF SFRC


Seamless industrial floors are increasingly replacing jointless floors. Whereas jointless floors still have contraction joints every 40 meters or less, seamless floors have no joints whatsoever, no matter how large the surface of the floor is. The optimized crack control and high impact resistance of the series in combination with only a top mesh provides a system with intensive usage, and reduced maintenance and repair costs.

Fluid tight floors, water tight structures and coated slabs


It has been specifically designed to affect cracks between 0.1 and 0.3mm, enabling you to create durable fluid and/or water tight structures with the most stringent serviceability requirements. Combined reinforcement can also be used as the substrate for hard thin toppings such as epoxy layers and other coatings. Along with only one top mesh a crack width limitation designed for the specific SLS requirement can be applied. A coating was applied in order to assure tightness. The slab is subject to a very stringent crack width limitation in order to allow the coating to remain undamaged. A combined solution with only a top mesh + high performing SFRC is a most practical, economical and time saving way of construction.

Structural floors and seismic floors

Industrial floors are usually ground-supported and not interfering with the integrity of the actual building. However, there are structural floors on which the entire building is erected. Those floors additionally act as foundation slab that is bracing and carrying the entire building load. The raft foundation of a 30m high production facility. The whole building is erected on the slab with cantilever columns exerting loads of more than 5 MN and 2 MNm into the slab. An additional requirement was for a seamless construction with crack width limitation to 0.2 mm. Design and execution was in combined reinforcement saving around 60% of the traditional reinforcement that would otherwise have been required. The tremendous effect of this solution was the time saving outcome and the practicability.

In seismic areas, floors function as a tie beam for structural elements, such as columns and pad foundations. Significant uplift forces, and in plane forces during a seismic event, have to be dealt with. A combined solution offers a practical, economical and time saving solution.


Floor on piles


SFRC floors on piles have already been carried out from time to time though with stricter limitations in terms of pile distances, slab thickness and additional amount of reinforcement. All as to date executed SFRC piled floors were usually solutions with additional reinforcement along the pile grid or with a piece of mesh above the piles. Because of its exceptional load bearing capacities, it enable the construction of floors on piles without traditional reinforcement. This does not only save time during construction, but also creates new possibilities for floors on piles.

Clad Rack foundations 

Clad Rack warehouses are any type of storage system in which the shelving facility is part of the building structure, thereby avoiding the need for the civil works of a conventional building. For this type of warehouse, the shelving facility not only supports the load of the stored goods, but also the load of the building envelope, as well as external actions, such as wind, snow and seismic actions. Most clad rack buildings are automatic systems (AS/RS) using robotic equipment for handling loads.

 Accordingly the foundation of this racking system is a real raft foundation that additionally has to fulfill the requirements of a floor. The raft is executed before the rack system is erected, meaning temperature needs to be considered for a monolithic slab type. A typical solution with SFRC can be in combination with or even without the use of mesh or any other traditional reinforcement methods. Because of its unique capabilities, it provides utmost strength and durability to preserve the integrity of the clad rack structure from downward forks, uplift from wind loads and seismic forces. The elimination of traditional reinforcement can achieve significant savings

 Raft foundations

Steel fiber reinforced concrete has been used for years in foundation slabs of residential buildings. The legal possibility to design this kind of load bearing structure was supported by local general approvals. However foundation slabs have been limited to certain loads and size measurements. Due to recent codes (e.g. German Guideline) there is no limitation, neither of applicable loads nor to the size measurement. As such raft foundations of multi storey buildings of any kind can be executed with SFRC, or combined reinforcement respectively. Since these are in most cases heavy loaded rafts, big in size and subject to a stringent crack width limitation combined reinforcement is mostly applied. As a rule of thumb about 50% of the traditional reinforcement gets replaced. This is clearly depending on the SFRC performance are particularly favorable and will generate bigger savings. The raft foundation of the building was carried out in combined reinforcement. One main reason for the decision towards SFRC was to minimize shear studs and shear reinforcement. With the solution using combined reinforcement both has been achieved. Bending reinforcement and reinforcement for crack width requirement has mainly been reduced. On top most foreseen shear studs and shear reinforcement have been completely skipped by the combined solution. As such cost saving, time saving and constructability have been the main reason for this solution. The key applications of the extended application area for SFRC. Different elements other than those mentioned herein are certainly also possible.








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