Especially going through the diff. weight gain chart for reference for diff. bigger breeds, I had observed the weight gain ration doubled during 8 week to 12 week period.

So on an average 8 week to 12 week is when the puppy expected to show the Growth spurt putting on 20 lbs instead of 10 lbs per average till it achieve its adult weight.

Is there any other symptoms we can observe other then gain in weight to identify that our puppy is going through the growth spurt period ?

It depends on he individual breed, and the individual breeder really.

You can have a Great Dane that reaches it's full height by 9 months, but one from a different breeder that reaches its full height at 11 months.
Just like people genetics plays a huge part in how they grow and at what time they will have growth spurts.
The best person to talk to about a particular dog growth spurts would be the breeder, if they have been using the same lines for many years, they should have a rough idea about how their dogs grow.

A sign that a larger breed dog is developing too quickly would be bone problems. Large and Giant breeds that are fed a diet too high in protein can grow rapidly, but their bones just can't keep up and it can cause deformities.
Usually the first things to go are the pasterns (front wrists) and hocks (back 'ankle') you will see them start to bend forwards and if left untreated the dog will eventually be unable to walk.

A good many animals will tend to get hiccups while sleeping during growth spurts. This doesn't happen all the time but it does happen frequently. Our nine month old Dobe averaged about half an inch (1 cm) per about of hiccups.