Assessment of Existing Buildings
Assessment of Existing Buildings
(OP)
Dealing with a cantilevered street awning (tie-back through unreinforced brick parapet into return parapets at ends and into roof between), which are very common here in Australia. Client is replacing awning as it projects too far and trucks and caravans run into it. New awning is smaller(to eliminate chance of vehicular impact) and lighter (assessed uplift still not an issue).
Existing structure needs assessment as to its ability to carry new awning. Current issues under consideration --
1)Condition of existing fixings - will be replaced as required - no problem.
2)Weight and Plan area reduction of awning reduces "available" loading - reduces risk as compared to existing.
3) Reducing projection SIGNIFICANTLY reduces risk of failure, as any impact could of been its last.
4)Live Load requirements for street awnings has gone up significantly since original construction(from 0.25kPa to 1kPa) - although original is 40-50 years old and probably would not have been designed per se. This new demand is much greater than reduction from point 2). Current tie-back into roof system is in good condition but when load path is fully tracked, it lacks capacity to carry new live load.
5) Unreinforced brick parapet itself is a high risk item that have poor track record under lateral loading - retrofit while we can is my take.
Client is obviously doing the right thing by addressing point 3 above, yet are not so willing to pay for works addressing points 4 and 5.
Is there any regulations (I'm in Australia), that allow purely condition assessment and have provisions regarding allowable %change in loading, whereby upgrading is not required?
To clarify, if loading was to increase by say 5%, or in this case, load decreases slightly due to plan area reduction, then attention to condition is all that is required, as keeping structures up to date with every loading code change would not be practical.
In summary, without strengthening the supporting structure, but attention to its condition, the installation of this new awning reduces the risk to the public. On the other hand yet it is an opportune time to strengthen - which is my preference, client less so.
Any thoughts or experience on the matter greatly appreciated.
Toby






RE: Assessment of Existing Buildings
RE: Assessment of Existing Buildings
structure directly related to new awning is been strengthened to current requirements.
Anyone know of % change in capacity/loading rules here in Australia that waive any upgrading/strengthening requirements?
Toby
RE: Assessment of Existing Buildings