1)What certificate is important and valuable in construction field that can help increase your value as engineer?

For example

Scaffolding Certificate
Chargeman
Wireman

What else you think?

2)Diploma or Degree in Mech Eng for constructions field.

3)Design section or site supervising? Which can help to rise up faster?

1.so experience matters? Doesn't the extra certificate means anything
2.ok
3.how to enter design section.....what if my comp put me in other section

For point 3,
It is one of the most discussed topic for people who work in construction line.
We usually compare client / developer / consultant and contractor.

In short, we can conclude that.. it is pretty shit when you are not bosses of the company.

But as a employee usually working as client / developer will be more "valuable".

Consultant / contractor can be very subjective.. as long as one is capable and they can be well paid.
As company earning, contractor usually have better margin compare to consultant. But of course contractor always has higher risks. (cash flow problem.. not getting paid, screw up project and lose money)

and i heard some ppl in the industry claiming that the ladies engineers at the site are always discriminated given little to no respect by the foreign workers. May i know how true is that?

Because they just have to like instruct people to work for them only? coordinate and manage ppl.
All the design liability is on consultants?
Usually higher paid?

ya, as long as you guys get the idea.
But sometimes when you are the action party and they just instruct you to do this and that like nobody business.. really     
But we all know everyone has a role to play.

Ever see the joke that project manager mentality is that 9 women can give birth in 1 month?

why after apply waterproof on floor, still have leaking?

What is the best way to apply waterproof coat on toilet floor?

Anyone know how to calculate the tonnage of concrete spun pile? I want to price the MLT test of the 400mm diameter spun pile.