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									                                                                    Module Code: CN3331
                                                                              Page 1 of 6


                        BUILT ENVIRONMENT DIVISION

                              EXAMINATION PAPER

Module:                                 Construction Technology 4

Module Code:
                                        24 May 2004
Date of Examination:
                                        9:30 – 12:30
Time of Examination:
                                        Amrit Sagoo
Examiner(s) Room:
                                        3 hours
Time Allowed:
                                        Answer 4 questions in total
Number of Questions to be attempted:    Section A - Compulsory
                                        Section B - Answer any 3 questions

                     CONSTRUCTION TECHNOLOGY 4
                           Examination Brief

Your client is a firm of private developers specialising in commercial projects. They have
recently taken an option to purchase a site in Shropshire comprising:

A redundant Royal Air Force (RAF) residence buildings, together with the freehold of
approximately 21 acre of redevelopment land to the rear which is presently used for
parking aircraft. The rear of the site is also occupied by several single storey
prefabricated buildings (used as aircraft hangers / storage / repairs etc) each building
having a gross external floor area of 5000 Sq. Metres.

The residential and prefabricated buildings were designed in 1930’s under the direction of
the Air Ministry as part of the re-armament programme.

The site is located in Cosford, a valley surrounded by hills having steep slopes on all
sides of the site. The site enjoys scenic views’ (looking onto the country side and the
Shropshire hills), which attracts tourists. The site fronts onto the main high street, which
accommodates a mix of uses such as residences, shops, offices and commercial buildings

The Residential Building

The basic structure of the residential building comprises reinforced concrete columns
with concrete flat roof construction and concrete blockwork with render finish. The flat
roof is covered with asphalt surrounded by reinforced concrete parapet wall built off the
concrete roof slab. The floors are insitu concrete and galvanised steel framed side-hung
casement windows are incorporated into the cladding panels to provide natural light and
ventilation to the interior.

The Prefabricated Building
The prefabricated building at the rear comprises a steel structural frame with part
brickwork (up to 1.5M) and concrete shell walls overlaid with asbestos sheeting. The
building(s) are enclosed with a barrel roof made up with concrete shell construction with
asbestos sheeting painted with bitumen.

State and Condition
The residential building has major defects of the structural frame such as:

   i.      cracking of the exposed areas of the concrete
   ii.     rusting of the reinforcements.
   iii.    dampness on the walls and floors.
   iv.     severe cracking of the render finish.
   v.      mould growth; pattern staining and efflorescence on the walls

Detailed laboratory testing has indicated that these defects are mainly related to chemical
attack associated with carbonisation, sulphate attack, calcium silicate reaction, high
alumina cement and chloride attack. The building also has presence of asbestos (blue
and white asbestos) based material located around service pipe work and ducts.

The prefabricated building has a history of structural movements and consequently it has
been vacant for the last 20 years. Structural movement associated with insufficient
bearing capacity of the ground, adverse point loads internally resulting in cracking of the
floor slab and movement of the portal frame and deterioration of asbestos panels due to
poor patch repairs in the past together with general ageing. This exhibiting the following

i. Rainwater penetrates through the vertical / horizontal joints of the asbestos; resulting
     in diagonal cracking to the inner skin and rusting of the frame structural.
ii. The external cladding is exhibiting evidence of weathering as evidenced by the
     asbestos sheeting becoming delaminated with breakdown of fibres progressively
     being exposed together with visible rusting.
iii. Floor slab fractured allowing damp patches to appear (which frequently appear /
     disappear). External brickwork exhibits evidence of rising damp.
iv. The structure has in places sunk into the ground approximately 1M,


Preliminary planning enquiries indicate that so far as the residential building is concerned
planning consent would be forthcoming:

   a. demolition of the existing structure and replacement with new structure having
      same footprint, with car parking provision being accommodated in the basement


   b. retain the existing building, undertake substantial structural repairs to bring the
      property fit for human habitation by redesigning the internal layout and providing
      self contained luxury apartments.

In the case of the single storey prefabricated block the planning authority has indicated
that no objection would be raised to its demolition and replacement by out of town a one-
stop shopping centre having a low-rise long span structure.
Your Client has expressed concerns regarding the speed of construction, demolition;
health and safety aspect in design, construction and management; aesthetics, position of
the proposed works adjacent to existing buildings, energy efficiency and maintenance

The situation of the buildings together with the adjacent land are shown on the attached
location plan. Internal layouts are shown on the floor plans also provided. The drawings
(2No. in total) provided are incomplete but give indicative details of the property.

SECTION A - Compulsory Question
1.         Your Client has retained your company as Project Managers (offering a full
           range of services ranging from Professional Design services together with
           Health and Safety).
           As a Principal Contractor prepare a health and safety plan to accompany the
           tender documentation for the demolition and or refurbishment of the existing

     iii   In particular, your clients are concerned that they discharge their statutory
           obligations under the CDM regulations, in addition to the health and safety
           plan. Explain the workings of the CDM regulations and how these affect them
           as developers throughout the entire contract (ie demolition, new build and
           refurbishment).                                                                 10%
SECTION B - Answer any 3 questions
2. i.    Describe and evaluate in detail the principal causes of the chemical reaction and
         the symptoms of any two the following defects in concrete structures:

         i.     Carbonisation,
         ii.    Sulphate attack
         iii.   Chloride attack.                                                               2 x 5%
         v.     High Alumina Cement.

   ii.   Write a specification to remedy any of the above two defects in concrete
         structures                                                               2 x 5%

3. a     If the existing residential buildings were being retained, explain to your client      15%
         how the existing building could be up-graded to ensure that the building is fit for
         human habitation.

   b     Your client is keen on green issues and wishes the energy efficiency of the
         retained buildings to be up graded to a standard approaching that of new build

         Using annotated and detailed sketches to support your response, advise your             5%
         clients how this might be achieved.

4. i.    Advise your client on the implications of the presence of asbestos upon the users
         and occupiers of the buildings.                                                        10%

   ii    The importance of any precautionary measures that need to be implemented if:
   a.    Asbestos was to be retained                                                             5%
   b.    Asbestos was to be removed                                                              5%
5.   Your client is considering the introduction of a planned maintenance system for
     the project as a whole.

     Using examples where appropriate, provide a detailed commentary and
     description of the application of the decision-making procedure for setting up a
     maintenance programme.                                                             20%

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