The self drilling hollow bars production and testing according to EN14490, ASTM F432, EN14199, EN100803, FHWA-NHI-14- 007 and other standards.
Rope/ R thread was firstly invented by MAI in 1960s to solve the low construction speed on complicated underground works. R thread is designed and produced according to ISO 10208 (R25, R32, R38) and ISO 1720 (R51). The thread is usually left hand. R thread anchor bar can be connected and installed quickly in the loosing or collapsing stratums, which could be drilling and grouting in one step.
T thread is designed and produced according to T International Standard, and the rod anchor types are: T30, T40, T52, T73, T76, T103. T thread makes itself good bond to the accessories or rotary drill rigs. Its high strength makes it widely used in deep foundation, slope stabilization, tunnel, mine or other geological disaster areas.
If the rib height increases or the number of ribs per unit length increases, the relative rib area increases. The rib area fR is used as a parameter for the bonding quality of T thread anchor bolts, and the optimal value is fR = 0.21 - fR = 0.33.
Both R thread and T thread anchor bar can be done hot dip galvanize in accordance with EN ISO 1461:1999. The use of hot dip galvanized steel reinforcement anchor bar can increase the service life of structures that normally suffers from carbonation induced reinforcement corrosion. The chloride threshold value of zinc is higher than black steel, so galvanized reinforcement also lengthens the service life of structures that are exposed to chlorides. However the galvanizing changes the geometry of ribbed reinforcement bar by smoothing the ribs and decreasing their height and thereby affects the bonding between reinforcement bar and structures.
AISI 316 stainless steel is popular used in R thread anchor bar manufacturing. The bond of the anchor bar is in accordance with BS 8110 and BS 6744, the continuous thread provides a key for the grout. Stainless steel anchor bar is about 3 times stronger than ordinary steel anchor bar, with its high anti-corrosion property, it is mainly used in high corrosion conditions.
Bending self drilling hollow bar is to test its ductility on site, as well as to check:
This is a special customized bar, bending properties up to standard ISO 1519 and impact properties standard ASTMD 2794.
As a self-drilling anchor bolt manufacturer, ONTON supplies high-quality self-drilling anchor bars and reliable tests.
The company’s wholly-owned R&D center has strong R&D capabilities and the ability to transform technology into productivity, and maintains good cooperative relationships with many domestic research institutions and scientific research schools.
Complex geological conditions such as weak surrounding rock and fault fracture zones are common in various underground projects, which brings great difficulties to the construction of rock anchors. Especially in the case of serious hole collapse and the need for extra-long anchor rods. The self-propelled (drilling) hollow grouting anchor series integrates drilling, grouting and anchoring functions, and can be used in tunnel advance support, radial support and various slope treatment projects. It can very well improve the surrounding rock and achieve the ideal support effect.
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