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Structural design processes: Difference between revisions

Structural design processes (view source)

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Structral design requires the use of [[System Planning|system planning]] i.e. the overal process and the sub-processes need to be optimised.
Structural design requires the use of [[System Planning|system planning]] i.e. the overal process and the sub-processes need to be optimised.


Figure 1 shows how, when creating a structure, one starts with a set of requirements that define the performance of the structure. This is transformed by a design process into design output, i.e. into information about what the structure will be and justification for the design decisions..  A construction process then transforms the design output into the physical structure.
Figure 1 shows how, when creating a structure, one starts with a set of requirements that define the performance of the structure. This is transformed by a design process into design output, i.e. into information about what the structure will be and justification for the design decisions..  A construction process then transforms the design output into the physical structure.
[[File:Structure-process.png|none|thumb|600x600px|Figure 1  Stages in the creation of a structure]]
[[File:Structure-process.png|none|thumb|600x600px|Figure 1  Stages in the creation of a structure]]


=== Models of the design process ===
[[File:Structure-process-2.png|thumb|400x400px|Figure 2 Design process stages]]
[[File:Structure-process-2.png|thumb|400x400px|Figure 2 Design process stages]]


==== A basic model ====
=== A basic model of the design process ===
Figure 2 shows a model of the design process. The 'system model' is information about the stucture being designed and about its  context.
Figure 2 shows a model of the design process. The 'system model' is information about the stucture being designed and about its  context.


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At the Production Stage, the chosen form of structure is developed to produce drawings and specifications to be passed on to the construction stage. Other outcomes include  documents that justify the decisions taken.
At the Production Stage, the chosen form of structure is developed to produce drawings and specifications to be passed on to the construction stage. Other outcomes include  documents that justify the decisions taken.


==== Process mapping ====
=== Process mapping ===
The Institution of Structural Egineers publishes a Structural Plan of Work that sets out an overall process for structural engineers working on the design of a building.  
The Institution of Structural Egineers publishes a Structural Plan of Work that sets out an overall process for structural engineers working on the design of a building.  


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* ''Validation'': Is the process suited to the context?
* ''Validation'': Is the process suited to the context?
* ''Verification'':  Has the process been correctly implemented?
* ''Verification'':  Has the process been correctly implemented?
==== '''Analysis modelling''' ====
Use the strategies recommended in this document.
==== '''Code of practice conformance''' ====
'''Validation of code provisions'''
Ensure that the design context is within the scope of the codes that are specified in the Structural Design Brief. If it is not, seek to ensure that relevant issues that are not covered in the codes are addressed. This is especially important in innovative contexts. See, for example, the [[Structural design failures|Ronan Point Collapse]]
'''Performing the calculations'''
Code of practice rules should be processed using software that has been subject to rigorous QA assessment.
Hand calculators should only be used in preliminary work and back-of-an-envelope checks. They should not be used for final calculations because of the increased risk of errors when values are being keyed-in.
See guidance on programming of calculations.
'''Input checking'''
Verify input to software
'''Results transfer'''
Verify that the results have been correctly transferred to drawings and schedules,


=== Inception Stage ===
=== Inception Stage ===
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* The requirements that have been addressed at the end of Stage 2.     
* The requirements that have been addressed at the end of Stage 2.     
* Actions/processes needed at the Production Stage to ensure that all requirements will be properly addressed.
* Actions/processes needed at the Production Stage to ensure that all requirements will be properly addressed.
* Issues to be addressed that are not included in codes of practice.
* Issues to be addressed that are not included in codes of practice. This is especially important in innovative contexts. See, for example, the [[Structural design failures|Ronan Point Collapse]]


=== Production Stage ===
=== Production Stage ===


==== Technical assessment ====
==== Technical assessment ====
Technical assessment is the use of analysis modelling and performance criteria to seek to ensure that the structure will satisfy the technical requirements set out in the Design Brief - Stage 2. The main structural engineering standards used in the UK are the Eurocodes [[https://www.bsigroup.com/en-GB/our-services/standards-subscription-services/Eurocodes-Plus/what-are-eurocodes/ [1], [[:en:Eurocodes|2]] ].  A main requirement of technical assessment is to ensure that the strucutre will be stable i.e. that it will not be close to collapse.  
Technical assessment is the combined use of analysis modelling and performance criteria to seek to ensure that the structure will satisfy the technical requirements set out in the Design Brief - Stage 2. The main structural engineering standards used in the UK are the Eurocodes [[https://www.bsigroup.com/en-GB/our-services/standards-subscription-services/Eurocodes-Plus/what-are-eurocodes/ [1], [[:en:Eurocodes|2]] ].  A main requirement of technical assessment is to ensure that the strucutre will be stable i.e. that it will not be close to collapse.  


'''Analysis modelling'''
'''Analysis modelling'''
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There is significant risk that errors in the modelling will cause the structure to be unsafe and therefore a fit for purpose [[analysis modelling process]] must be used.  
There is significant risk that errors in the modelling will cause the structure to be unsafe and therefore a fit for purpose [[analysis modelling process]] must be used.  


'''Conformace to technical criteria'''
==== Conformace to technical criteria ====
 
'''Validation of technical criteria'''  
The code of practice


'''Validation of code provisions'''
It is essential that all the relevant code of practice critera are addresses. It is also very important to be vigilant for issues that are not covered by codes of practice and may not have been identified in the Design Proposal - Stage 2 document.
 
Ensure that the design context is within the scope of the codes that are specified in the Structural Design Brief. If it is not, seek to ensure that relevant issues that are not covered in the codes are addressed. This is especially important in innovative contexts. See, for example, the [[Structural design failures|Ronan Point Collapse]]


'''Performing the calculations'''
'''Performing the calculations'''
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'''Input checking'''
'''Input checking'''


Verify the input to software
A process is needed for checking that:


'''Results transfer'''
* the input to calculations is correct,
 
* the calculations has been correctly implemented
Verify that the results have been correctly transferred to drawings and schedules,
* all criteria have been satisfied.


==== Drawings and specifications ====
==== Drawings and specifications ====


 
A process is needed to verify that the decisions made are correctly implemented in the drawings and specifications that are used to construct the structure and for other purposes.
==== Design verification report ====
==== Design verification report ====
This report demonstrates that the mandatory requirements have been satisfied and shows how the non-mandatory requirements have been addressed.
This report should :
 
It records validation of the processes used and how the processes were verified.


It serves as a record for archiving purposes of what has been done .
* demonstrate that the mandatory requirements have been satisfied and show how the non-mandatory requirements have been addressed.
* record the validation of the processes used and how theys were verified.
* serve as a record for archiving purposes of what has been done .


Typical contents of a verification report:
Typical contents of a verification report:
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