In mid-2008 DEMU adapted its bar anchors. Bar anchor 2010/3010 was replaced by type 4010. Type 4010 has a turn-in length (a size) that meets the constructive requirements for coupling, fixing and lifting. The 4010 is also not oversized so time can be saved on the building site when turning in.

 

The screw-in length of the 4010 bar anchors is between the old 2010 and 3010. The a size suffices with regard to the 1.5 times the thread diameter parameter. The a size is also matched with the lifting gear. Obviously the system remains suitable for coupling.

 

Besides type 4010 type 3010 (with re-usable plastic nailing plate 3016) remains for stainless steel, and type 2010 remains for round 40. Per bar size there are differences in screw-in lengths (a sizes) for these bar anchors. The following is a summary of these screw-in lengths.

 

Table: a-sizes

type bar     Ø12/M16     Ø16/M20     Ø20/M24     Ø25/M30     Ø32/M42     Ø40/M48

4010 EV/TV    25              33             38            48               65              -

3010 A4-80    29              35             46            60                -               - 

3016 EV         29              35             46             -                 -               -

2010 Ø40 EV   -                -                -              -                -              48

 

The strength of anchors is determined by the weakest diameter.

In the past, just like its colleagues DEMU used stainless steel 316 Ti connectors with a yield stress of 240 N/mm² (class 50). By using these connectors on bolt anchors 1988 with bolts 8.8 (yield stress 640 N/mm²) and bar anchors 3010 with concrete steel FeB 500 (yield stress 500 N/mm²) the strength of these anchors was determined by the relatively “weak” connectors. In comparison with the galvanised versions of these products the normative bend load was significantly reduced. Using special class 80 connectors (yield stress 640 N/mm²) this reduction is prevented and it is no longer the (only) determining diameter.

With bolt anchors 1988 stainless steel 316 Ti class 80 steel breakage (according to the CUR 25) will almost never be the normative failure mechanism.

With bar anchors 3010 stainless steel 316 Ti class calculating maybe done with the yield stress of the concrete steel (NEN 6720).

 

A bolt anchor must be fully cast in. With sufficient concrete cover it is not necessary for the bolt to be treated (comparable with concrete steel). The end of the bolt body in the locked connector and the inside of the screw thread insert are also untreated. The bolts turned in the anchors must therefore be electrolytically or hot dip galvanised. The zinc coat on these bolts will protect the end of the untreated bolt body and the untreated inside of the screw thread insert. Also see galvanic corrosion!