Expert: Arshad Khan - 5/5/2003

Question
1)Whart services are required in a medium rise building & how are provisions made for there distibution?

2)an infill building is to be erected over a derelect site bounded by medium rise buildings circa 1930.how would you arrange the new framed building on the site to within 50mm of those existing?considering superstructure & foundations.

3)how many different types of bridges are there?what are there advatages & disadvantages?how is thermal movement at bearings accomodated?

4)what would your recommendations be in installing a drainage pipe across a majior road link?

Thankyou very much for answering these questions for me im stuggling a bit in my course.Your help is greatly appriteated.Please help me.

Answer
Hi Glenn,

I have already answered 1, 2 and 4 as below, and now answer 3.

Although I cannot give you detailed design information over this medium, I
can give you some guidelines:

1. For a medium-rise building, the main services would be lifts, fire
escape staircases, fire-risers (wet or dry), ventilation shafts and
sanitary drains. Possibly also a rubbish chute, if it is residential. All
these are usually accommodated within a service core, which in most cases
also doubles as the main lateral-stability structural stability spine.

2. If the new buildings foundations are to be below the existing buildings
(e.g. due to a deeper basement, etc), then you would need to do some form
of piling around the perimeter. This could be steel sheet piling, or
contiguous concrete bored piling, temporarily braced until the new
structure fills the void. If the new building's foundations are at the
same level or slightly higher than the existing, then no special
arrangements are necessary. If the new building's foundations are much
higher level than the surrounding buildings, then the former need to be
transmitted down to the same level by means of piles.

3. The main types of bridges are: Arch, suspension, truss, cable-stayed, and simple beam. These can be in reinforced concrete or pre-stressed concrete, or steel, or composite, or in timber for smaller spans. Suspension are best for very long spans, arch are good for medium spans, etc. The thermal expansion is accommodated by having at least one support capable of rolling or sliding within an expansion joint.

4. These days the best option, in order to avoid traffic chaos, would be
to use either mini-tunnelling, or else pipejacking methods. Both these
obviate the need to trench across the road surface. Check out the website
www.nodiginternational.com


I hope this is of help!!

Kind regards,

Arshad