Tension splice

In Chapter 8 two potential applications for the bonding of structural steelwork will be considered in some detail. These are bonded web stiffeners and tension splices or cover plates to girder flanges. 

Tension splices, beam splices and cover plates... 

Greaser, M. L., Berri, M., and Warren, C. M. (2002). Species variations in cDNA sequence and exon splicing patterns in the extensible I-band region of cardiac titin Relation to passive tension. / Muscle. Res. Cell Motil. 23, 473-482. 

Figure 18.3 is an extrusion line schematic drawing of tension control equipment for the unwinding substrate. The arrows indicate the motions of the driven tension control rolls and idlers as well as the substrate, and the direction of outward pressure-on the rolls. Figure 18.4 is what is called a flying splice on a double-station-unrolling stand where ... 

Leech CM, Hearle JWS, Overington MS, Banfield SJ. Modelling tension and torque properties of fibre ropes and splices. Proc Int Offshore Polar Eng Conf Singapore 1993 11 370-6. 

TRM and FRP jackets provide additional contribution to the transverse steel reinforcement tension resistance against splitting cracks, as illustrated in Fig. 12.4b. In order to account for this contribution of FRP or TRM confinement on the local bond strength of lap splices, it is reasonable to add a new parameter K,rj to the transverse reinforcement parameter K,r provided by the stirrups. The proposed modified term Ktr,t, which accounts for the total confinement applied by both the contribution of stirrups and FRP or TRM jackets, is expressed as ... 

Since the lapping of the column reinforcement can only take compression forces, a lap splice failure in tension would be highly detrimental to the whole experiment. In order to safeguard against this type of failure and allow the test to be performed without any premature failure, it was decided to reinforce the bounding columns of the wall at the 1st floor with three-sided CFRP (carbon fibre reinforced polymer) for a height of 0.60 m from the base of the column (Fig. 17.5). 

This changed at about 5.95 s, when the strain in the east column (Channel 6) increased suddenly to 0.0065 mm/mm, and it continued to be larger than the east bounding-column of the south wall (Channel 4 + 5), in most of the cases, and remained in tension for the rest of the experiment. This was associated with the sudden failure of the lap-splice of this coluirm and the formation of a crack which increased the recorded displacement resulting in a permanent strain of 0.00055 mm/ mm or a displacement of 1.51 mm, which is noticeable in Fig. 17.14. Therefore, although the graph shows an increase in the strain of the outer column, this is not true since it is due to the formation of the crack. 

In Fig. 21.7, two typical arrangements are shown. Type 1 is the simplest one, where there is space for all cords to be directly included. The Type 2 splice shows how the alternating tension principle is maximized in conditions where there is insufficient space between cords for the simple arrangement of Type 1. These two arrangements, together with one more appear in DIN 22131. For the Selby belt, BTR evolved a special design for maximum splice strength. 

The principles of splice construction have been described in Section 21.3.6. For the Selby belt the length of overlapped embedment, with alternating tensions, is 1200 mm for each cord. This is achieved in a special design of splice (undisclosed), covering a total length of 6 m. 

Thus approximately 1 week s cycles - 150 000 cycles - 15 years service under tensions which are similar to those of actual service. At the end of the cyclic part of the test, the splice is tensile tested. A test rig designed for anchor chains is used for this. Table 21.2 shows typical results. The splice retains 90-100% of its strength. 

Four main factors should be considered when selecting a PSA for a core start or splicing application substrates to be spliced, oven temperatures, line speeds and web tension. These factors should be evaluated through every step of production—from the beginning processes to final product conversion. Proper consideration ensures that the right splicing product (or combination of products) is used, which helps reduce or eliminate splice failure at any point in the process. 

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