more questions Flashcards
1
Q
advantages of cold forming hollow steel sectionS?
A
- cheaper
- require less energy
- better for the environment
2
Q
disadvantages of cold forming hollow steel sections?
A
- risidual stress @ corners, failure at lower temps
- rounder corners- harder to weld
- prone to distortion
- galvanised steel can delaminate at the corners
3
Q
welding value between o.25 -0.5? what happens?
A
hydrogen embrittlement can occur, if it is put into controlled cooling environment, i.e. preheating the zone to be welded
4
Q
what is cathodic protection?
A
- corrosion protection technique
- structure to be protected is wired to highly INERT electrode
3, steel becomes cathode - other metal is not prone to corrosion , only happens slowly
5
Q
what is galvanisation?
A
coating of a metal with a thin layer of another metal
6
Q
why does in situ test need to be carried out
A
- location of fault from records
- visible defects
- concern about performance
- change use of structure
- inspection
7
Q
what preservatives can u use on timber?
A
- tar oil preserves
- water soluble
- organic solvent
8
Q
what is pozzolanic based reaction?
A
lower early strength development strength but long term strength is increased
9
Q
why is lightweight materials better?
A
energy savings reansportation/ handling
less material- less demanding on sources
lightweight -low thermal conductivities
