The "Design and Construction Standards for Ground Anchors" and the accompanying commentary state that

Pull-out Test P182

Cycle	Test Load	Load Holding Time (min)
		Sandy soil-rock formation	Cohesive Soil
1	0.40 Tp	15	15
2	0.55 Tp	15	15
3	0.70 Tp	30	60
4	0.80 Tp	30	60
5	0.90 Tp	30	60
６	1.00 Tp	60	180

 

Aptitude Test, p. 189

Cycle	Test Load		Load Holding Time (min)
	Rank B	Rank A	Rank B		Rank A
			Sandy soil-rock formation	Cohesive Soil	Sandy soil-rock formation	Cohesive Soil
1	0.40 Td	0.40 Td	1	1	15	15
2	0.60 Td	0.60 Td	1	1	15	15
3	0.80 Td	0.80 Td	5	5	30	60
4	1.00 Td	1.00 Td	5	5	30	60
5	1.10Td	1.25Td	30	60	60	180

 

It says so.

However,You can shorten both of them.

It says...

 

Based on my roughly 20 years of experience, for loads in the 1,000 kN class,

It takes about 30 minutes for the creep to stabilize,It takes about 15 minutes at the earliest.

The smaller the load, the shorter the time.

 

It's fine to maintain the holding load as planned, but,A waste of timeThat's it.