Civil Engineering Reference
In-Depth Information
Using the control strategies can be thought of as a formal
approach - as a Quality Assessment process. It can also be viewed
as a pervasive mode of thinking - of asking the right questions to
seek to ensure that what is being done results in good outcomes.
phase will push up the design costs. Changes to the requirements
at the construction phase can be very expensive.
The holistic view of design infers that all issues that may
affect the outcome should be taken into account. To achieve
this it is clearly necessary to have a focus on requirements
(
Figure 6.1
).
6.3 The design process - Inception
6.3.1 Design requirements
A successful outcome in design is dependent on the adequacy
of the requirements. With errors and omissions in the require-
ments the chance of a satisfactory outcome may be low.
Types of requirement for the design process include:
6.3.2 Design information
Figure 6.2
illustrates the role of information in the design pro-
cess. The input to, and the output from design are both in the
form of information. If the input information is not optimum
the success of the design outcomes is compromised.
Two types of information can be identified:
Project information - client brief, site plans, surveys, geotechnical
Client service brief - what service the designer agrees to provide
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for the client.
Client design brief - what the client wishes to be achieved from
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reports and the results of other investigations commissioned for
the project.
Design support in the form of codes of practice, cases of similar
the product to be designed.
Design requirements generated by the design team.
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■
design contexts, textbooks, journal papers, guidance documents, etc.
Best practice is to take the client brief and develop it into a
comprehensive set of design requirements irrespective of the
degree of detail in the client brief.
Some principles for developing design requirements are:
In non-standard situations more resources may need to be allo-
cated to creating project information and searching for design
support information.
Requirements must encompass objectives and constraints.
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6.4 The design process - Concept design
6.4.1 Development of options
It is said that the choice of concept controls the quality and the
cost of the final design. With an inadequate concept there is
little chance of success. Careful attention to the choice of con-
cept is an important feature of best practice structural design.
The requirements should, where possible, be expressed in per-
■
formance terms. Statements that will limit the form of the facility
being designed should be avoided unless (a) there is no realistic
alternative or (b) it is a client requirement.
It is important to seek to establish the requirements at the earli-
■
est possible time. Changes to the requirements during the design
Structural
Performance
Material
Specification
Aesthetics
Cost
Appearance
Sense of Place
Soil
Rock
Loading
D.L
L.L
Wind
Earthquake
Pressure
Blast
Wave
Subsoil
Superstructure
Strength
Stiffness
Durability
Stability
Robustness
Fire
Design
Production
Maintenance
Decommissioning
Steel
Concrete
Masonry
Timber
Plastic
Buildability
Sustainability
Maintainability
Subsoil Performance
Safety/Risk
Recycling
Re-using
Pollution
Energy
Waste
Fumes
Bearing
Settlement
Retention
Site
Access
Ground Conditions
Weather
Construction
Use
Re-use
Decommissioning
Alternative Sources
Embedded Energy
Use: Heating, Lighting
Movement
Figure 6.1 Generic issues in relation to structural design requirements
