Discussion: View Thread

In the recent discussion on SE licensure reference was made to complex structures. Given that what may be complex to one engineer may be routine to another what are examples of complexity that cause pause and why? See this link for background discussion.
https://collaborate.asce.org/integratedstructures/discussion/why-se-licensure#bm910d013d-ab5a-4c00-8ba5-2858ae527f59

In the recent discussion on SE licensure reference was made to complex structures. Given that what may be complex to one engineer may be routine to another what are examples of complexity that cause pause and why? See this link for background discussion.
https://collaborate.asce.org/integratedstructures/discussion/why-se-licensure#bm910d013d-ab5a-4c00-8ba5-2858ae527f59

Though there can be many different types of complex structures, the term is colloquial with regard to SE Licensure.  In SE Licensure, we typically talk about a threshold structure as opposed to a complex structure, but the intent is similar. 

The goal of SE Licensure is to provide reasonable protection to the public in extreme conditions, and to be effective, a building department official needs to be able to objectively recognize which structures are beyond the threshold and should be designed by an SE.  In New York, our proposal with regard to buildings that require an SE is as follows:  

1. Buildings included in Structural Occupancy Category III or IV.
   
2. Buildings in Occupancy Category II that are greater than 60 feet (18.5m) in height, have a clear span greater than 150 feet (46.3m), are in Seismic Design Category D, or have a total occupant load of more than 1000.
   
3. Buildings that serve as Elementary Schools, Secondary Schools, Hospitals, or Emergency Facilities regardless of their size.
   
4. Alterations where the Change of Occupancy is from an "SE not required" use to an "SE required" use would require an SE regardless of the level of alteration.
   
5. New York State Level I and Level II Alterations without a Change of Occupancy to a higher Risk Category are excluded.
   
6. Non-Structural Components and Delegated Design are excluded.

Clearly, with this definition of the threshold structure, the vast majority of buildings and even the majority of constructed area will not require an SE; however, a hospital, for instance, would.  

------------------------------
Brian Falconer P.E., S.E., M.ASCE
Principal
Severud Associates
New York NY

Original Message:
Sent: 03-09-2023 03:49 PM
From: Mitchell Winkler
Subject: What is a complex structure and why?

In the recent discussion on SE licensure reference was made to complex structures. Given that what may be complex to one engineer may be routine to another what are examples of complexity that cause pause and why? See this link for background discussion.
https://collaborate.asce.org/integratedstructures/discussion/why-se-licensure#bm910d013d-ab5a-4c00-8ba5-2858ae527f59

------------------------------
Mitch Winkler P.E., M.ASCE
Houston, TX
------------------------------

I am looking at the proposed criteria for the stratified PE/SE reqirement.  I am curious why an SE would need to design a wast treatement headhouse or wet well, SBR tank, etc. for waste treatment or water treatment.  These are Risk 3 structures, yet aren't complex.

Likewise for an educational building.  A competent PE is capable of designing a three or four story school building - these aren't complex buildings.  To establish a requirement that only SEs could design the building implies a PE isn't competent.

In this NY proposed criteria, I see deligated design isn't included.  How then does this square with the concpet?  A PE for all intent and purpose could be the steel framing connection designer. The SE in this instance is accepting that a PE is competent for the task when the deligated design is submitted for conformance.

An SE can be authorized to design those threshhold structures but may not have the requisite experience for a spcific design type.  It is once again incumbent on the licensed design professional to practice within one's competency.  That is no different than having a PE license.

A statement was made that the criteria can inform a building code official which appropriate dsign professional should be designing the structure.  This puts an licensure law enforcement obligation on the BCO.  Enforcement of the licensure law is not an authorized (by legislation) responsibility of the building code process.  In my experience, give a BCO an inch and they will take a mile.  I see no reason to extend their perceived jurisdiction.
------------------------------
Robert R Desmarais Jr, PE
President
rrd pe corp
313 West Liberty Street, Suite 101
Lancaster, PA 17603

Original Message:
Sent: 03-10-2023 01:48 PM
From: Brian Falconer
Subject: What is a complex structure and why?

Though there can be many different types of complex structures, the term is colloquial with regard to SE Licensure.  In SE Licensure, we typically talk about a threshold structure as opposed to a complex structure, but the intent is similar. 

The goal of SE Licensure is to provide reasonable protection to the public in extreme conditions, and to be effective, a building department official needs to be able to objectively recognize which structures are beyond the threshold and should be designed by an SE.  In New York, our proposal with regard to buildings that require an SE is as follows:  

1. Buildings included in Structural Occupancy Category III or IV.
   
2. Buildings in Occupancy Category II that are greater than 60 feet (18.5m) in height, have a clear span greater than 150 feet (46.3m), are in Seismic Design Category D, or have a total occupant load of more than 1000.
   
3. Buildings that serve as Elementary Schools, Secondary Schools, Hospitals, or Emergency Facilities regardless of their size.
   
4. Alterations where the Change of Occupancy is from an "SE not required" use to an "SE required" use would require an SE regardless of the level of alteration.
   
5. New York State Level I and Level II Alterations without a Change of Occupancy to a higher Risk Category are excluded.
   
6. Non-Structural Components and Delegated Design are excluded.

Clearly, with this definition of the threshold structure, the vast majority of buildings and even the majority of constructed area will not require an SE; however, a hospital, for instance, would.  

------------------------------
Brian Falconer P.E., S.E., M.ASCE
Principal
Severud Associates
New York NY

Original Message:
Sent: 03-09-2023 03:49 PM
From: Mitchell Winkler
Subject: What is a complex structure and why?

In the recent discussion on SE licensure reference was made to complex structures. Given that what may be complex to one engineer may be routine to another what are examples of complexity that cause pause and why? See this link for background discussion.
https://collaborate.asce.org/integratedstructures/discussion/why-se-licensure#bm910d013d-ab5a-4c00-8ba5-2858ae527f59

------------------------------
Mitch Winkler P.E., M.ASCE
Houston, TX
------------------------------

The proposed requirements assume that SEs will have upgraded structural engineering skills and experience relative to PEs. The proposed thresholds could create a situation where nearly similar structures have unequal levels of structural reliability in a hypothetical. What is the thinking here? 

SE's will still need to work within their competency area as horizontal structure experience does not necessarily translate to vertical structure experience and vice versa-Ditto for different materials. Unless the SE is differentiated, how will this be any different than the responsibility already placed on PEs that they must work in their competency area?

How has peer review been considered in the deliberations for the proposed requirements? Even the best of us can make mistakes. Here, I think of William LeMessurier and his design of the Citicorp Center structure. 

Is any periodic review planned to ensure the new requirements achieve the desired end?

I am looking at the proposed criteria for the stratified PE/SE reqirement.  I am curious why an SE would need to design a wast treatement headhouse or wet well, SBR tank, etc. for waste treatment or water treatment.  These are Risk 3 structures, yet aren't complex.

Likewise for an educational building.  A competent PE is capable of designing a three or four story school building - these aren't complex buildings.  To establish a requirement that only SEs could design the building implies a PE isn't competent.

In this NY proposed criteria, I see deligated design isn't included.  How then does this square with the concpet?  A PE for all intent and purpose could be the steel framing connection designer. The SE in this instance is accepting that a PE is competent for the task when the deligated design is submitted for conformance.

An SE can be authorized to design those threshhold structures but may not have the requisite experience for a spcific design type.  It is once again incumbent on the licensed design professional to practice within one's competency.  That is no different than having a PE license.

A statement was made that the criteria can inform a building code official which appropriate dsign professional should be designing the structure.  This puts an licensure law enforcement obligation on the BCO.  Enforcement of the licensure law is not an authorized (by legislation) responsibility of the building code process.  In my experience, give a BCO an inch and they will take a mile.  I see no reason to extend their perceived jurisdiction.
------------------------------
Robert R Desmarais Jr, PE
President
rrd pe corp
313 West Liberty Street, Suite 101
Lancaster, PA 17603

Original Message:
Sent: 03-10-2023 01:48 PM
From: Brian Falconer
Subject: What is a complex structure and why?

Though there can be many different types of complex structures, the term is colloquial with regard to SE Licensure.  In SE Licensure, we typically talk about a threshold structure as opposed to a complex structure, but the intent is similar. 

The goal of SE Licensure is to provide reasonable protection to the public in extreme conditions, and to be effective, a building department official needs to be able to objectively recognize which structures are beyond the threshold and should be designed by an SE.  In New York, our proposal with regard to buildings that require an SE is as follows:  

1. Buildings included in Structural Occupancy Category III or IV.
   
2. Buildings in Occupancy Category II that are greater than 60 feet (18.5m) in height, have a clear span greater than 150 feet (46.3m), are in Seismic Design Category D, or have a total occupant load of more than 1000.
   
3. Buildings that serve as Elementary Schools, Secondary Schools, Hospitals, or Emergency Facilities regardless of their size.
   
4. Alterations where the Change of Occupancy is from an "SE not required" use to an "SE required" use would require an SE regardless of the level of alteration.
   
5. New York State Level I and Level II Alterations without a Change of Occupancy to a higher Risk Category are excluded.
   
6. Non-Structural Components and Delegated Design are excluded.

Clearly, with this definition of the threshold structure, the vast majority of buildings and even the majority of constructed area will not require an SE; however, a hospital, for instance, would.  

------------------------------
Brian Falconer P.E., S.E., M.ASCE
Principal
Severud Associates
New York NY

Original Message:
Sent: 03-09-2023 03:49 PM
From: Mitchell Winkler
Subject: What is a complex structure and why?

In the recent discussion on SE licensure reference was made to complex structures. Given that what may be complex to one engineer may be routine to another what are examples of complexity that cause pause and why? See this link for background discussion.
https://collaborate.asce.org/integratedstructures/discussion/why-se-licensure#bm910d013d-ab5a-4c00-8ba5-2858ae527f59

------------------------------
Mitch Winkler P.E., M.ASCE
Houston, TX
------------------------------

SE's must have to have 3 to 4 years of experience in designing threshold structures.  PE's can have 3 to 4 years of any engineering experience.  Most SE's have a PE and an SE.  Discussing the comparative reliability between non-threshold structures and threshold structures is a complex discussion, but definitively I can say that the intent is to make threshold structures more reliable.   

Engineers always need to work within their competency, but when you have less directly relevant experience, you know less of what you don't know.  When you have more relevant experience, anyone makes better decisions about their own competency.  The SE's will be making the decision of if they are competent to design a waste treatment head house, a 60-story office building, or a hospital.   

Structural peer review is considered a separate issue from SE Licensure.  Some jurisdictions have SE, some jurisdictions have peer review, and some have both.  Peer review has been something that has proved to me the value of SE Licensure.     

SE Licensure is a state-by-state law; so, any state can legislate it how they want it.  I would be curious to hear an idea for periodic review - keeping in mind that we are sometimes designing for 50-to-2500-year events.  These events are ultimately going to demonstrate who knew what they were doing, and who did not.   

------------------------------
Brian Falconer P.E., S.E., M.ASCE
Principal
New York NY

Original Message:
Sent: 03-14-2023 02:22 PM
From: Mitchell Winkler
Subject: What is a complex structure and why?

The proposed requirements assume that SEs will have upgraded structural engineering skills and experience relative to PEs. The proposed thresholds could create a situation where nearly similar structures have unequal levels of structural reliability in a hypothetical. What is the thinking here? 

SE's will still need to work within their competency area as horizontal structure experience does not necessarily translate to vertical structure experience and vice versa-Ditto for different materials. Unless the SE is differentiated, how will this be any different than the responsibility already placed on PEs that they must work in their competency area?

How has peer review been considered in the deliberations for the proposed requirements? Even the best of us can make mistakes. Here, I think of William LeMessurier and his design of the Citicorp Center structure. 

Is any periodic review planned to ensure the new requirements achieve the desired end?

I am looking at the proposed criteria for the stratified PE/SE reqirement.  I am curious why an SE would need to design a wast treatement headhouse or wet well, SBR tank, etc. for waste treatment or water treatment.  These are Risk 3 structures, yet aren't complex.

Likewise for an educational building.  A competent PE is capable of designing a three or four story school building - these aren't complex buildings.  To establish a requirement that only SEs could design the building implies a PE isn't competent.

In this NY proposed criteria, I see deligated design isn't included.  How then does this square with the concpet?  A PE for all intent and purpose could be the steel framing connection designer. The SE in this instance is accepting that a PE is competent for the task when the deligated design is submitted for conformance.

An SE can be authorized to design those threshhold structures but may not have the requisite experience for a spcific design type.  It is once again incumbent on the licensed design professional to practice within one's competency.  That is no different than having a PE license.

A statement was made that the criteria can inform a building code official which appropriate dsign professional should be designing the structure.  This puts an licensure law enforcement obligation on the BCO.  Enforcement of the licensure law is not an authorized (by legislation) responsibility of the building code process.  In my experience, give a BCO an inch and they will take a mile.  I see no reason to extend their perceived jurisdiction.
------------------------------
Robert R Desmarais Jr, PE
President
rrd pe corp
313 West Liberty Street, Suite 101
Lancaster, PA 17603

Original Message:
Sent: 03-10-2023 01:48 PM
From: Brian Falconer
Subject: What is a complex structure and why?

Though there can be many different types of complex structures, the term is colloquial with regard to SE Licensure.  In SE Licensure, we typically talk about a threshold structure as opposed to a complex structure, but the intent is similar. 

The goal of SE Licensure is to provide reasonable protection to the public in extreme conditions, and to be effective, a building department official needs to be able to objectively recognize which structures are beyond the threshold and should be designed by an SE.  In New York, our proposal with regard to buildings that require an SE is as follows:  

1. Buildings included in Structural Occupancy Category III or IV.
   
2. Buildings in Occupancy Category II that are greater than 60 feet (18.5m) in height, have a clear span greater than 150 feet (46.3m), are in Seismic Design Category D, or have a total occupant load of more than 1000.
   
3. Buildings that serve as Elementary Schools, Secondary Schools, Hospitals, or Emergency Facilities regardless of their size.
   
4. Alterations where the Change of Occupancy is from an "SE not required" use to an "SE required" use would require an SE regardless of the level of alteration.
   
5. New York State Level I and Level II Alterations without a Change of Occupancy to a higher Risk Category are excluded.
   
6. Non-Structural Components and Delegated Design are excluded.

Clearly, with this definition of the threshold structure, the vast majority of buildings and even the majority of constructed area will not require an SE; however, a hospital, for instance, would.  

------------------------------
Brian Falconer P.E., S.E., M.ASCE
Principal
Severud Associates
New York NY

Original Message:
Sent: 03-09-2023 03:49 PM
From: Mitchell Winkler
Subject: What is a complex structure and why?

In the recent discussion on SE licensure reference was made to complex structures. Given that what may be complex to one engineer may be routine to another what are examples of complexity that cause pause and why? See this link for background discussion.
https://collaborate.asce.org/integratedstructures/discussion/why-se-licensure#bm910d013d-ab5a-4c00-8ba5-2858ae527f59

------------------------------
Mitch Winkler P.E., M.ASCE
Houston, TX
------------------------------

I am looking at the proposed criteria for the stratified PE/SE reqirement.  I am curious why an SE would need to design a wast treatement headhouse or wet well, SBR tank, etc. for waste treatment or water treatment.  These are Risk 3 structures, yet aren't complex.

Likewise for an educational building.  A competent PE is capable of designing a three or four story school building - these aren't complex buildings.  To establish a requirement that only SEs could design the building implies a PE isn't competent.

In this NY proposed criteria, I see deligated design isn't included.  How then does this square with the concpet?  A PE for all intent and purpose could be the steel framing connection designer. The SE in this instance is accepting that a PE is competent for the task when the deligated design is submitted for conformance.

An SE can be authorized to design those threshhold structures but may not have the requisite experience for a spcific design type.  It is once again incumbent on the licensed design professional to practice within one's competency.  That is no different than having a PE license.

A statement was made that the criteria can inform a building code official which appropriate dsign professional should be designing the structure.  This puts an licensure law enforcement obligation on the BCO.  Enforcement of the licensure law is not an authorized (by legislation) responsibility of the building code process.  In my experience, give a BCO an inch and they will take a mile.  I see no reason to extend their perceived jurisdiction.
------------------------------
Robert R Desmarais Jr, PE
President
rrd pe corp
313 West Liberty Street, Suite 101
Lancaster, PA 17603

Original Message:
Sent: 03-10-2023 01:48 PM
From: Brian Falconer
Subject: What is a complex structure and why?

Though there can be many different types of complex structures, the term is colloquial with regard to SE Licensure.  In SE Licensure, we typically talk about a threshold structure as opposed to a complex structure, but the intent is similar. 

The goal of SE Licensure is to provide reasonable protection to the public in extreme conditions, and to be effective, a building department official needs to be able to objectively recognize which structures are beyond the threshold and should be designed by an SE.  In New York, our proposal with regard to buildings that require an SE is as follows:  

1. Buildings included in Structural Occupancy Category III or IV.
   
2. Buildings in Occupancy Category II that are greater than 60 feet (18.5m) in height, have a clear span greater than 150 feet (46.3m), are in Seismic Design Category D, or have a total occupant load of more than 1000.
   
3. Buildings that serve as Elementary Schools, Secondary Schools, Hospitals, or Emergency Facilities regardless of their size.
   
4. Alterations where the Change of Occupancy is from an "SE not required" use to an "SE required" use would require an SE regardless of the level of alteration.
   
5. New York State Level I and Level II Alterations without a Change of Occupancy to a higher Risk Category are excluded.
   
6. Non-Structural Components and Delegated Design are excluded.

Clearly, with this definition of the threshold structure, the vast majority of buildings and even the majority of constructed area will not require an SE; however, a hospital, for instance, would.  

------------------------------
Brian Falconer P.E., S.E., M.ASCE
Principal
Severud Associates
New York NY

Original Message:
Sent: 03-09-2023 03:49 PM
From: Mitchell Winkler
Subject: What is a complex structure and why?

In the recent discussion on SE licensure reference was made to complex structures. Given that what may be complex to one engineer may be routine to another what are examples of complexity that cause pause and why? See this link for background discussion.
https://collaborate.asce.org/integratedstructures/discussion/why-se-licensure#bm910d013d-ab5a-4c00-8ba5-2858ae527f59

------------------------------
Mitch Winkler P.E., M.ASCE
Houston, TX
------------------------------

Though there can be many different types of complex structures, the term is colloquial with regard to SE Licensure.  In SE Licensure, we typically talk about a threshold structure as opposed to a complex structure, but the intent is similar. 

The goal of SE Licensure is to provide reasonable protection to the public in extreme conditions, and to be effective, a building department official needs to be able to objectively recognize which structures are beyond the threshold and should be designed by an SE.  In New York, our proposal with regard to buildings that require an SE is as follows:  

1. Buildings included in Structural Occupancy Category III or IV.
   
2. Buildings in Occupancy Category II that are greater than 60 feet (18.5m) in height, have a clear span greater than 150 feet (46.3m), are in Seismic Design Category D, or have a total occupant load of more than 1000.
   
3. Buildings that serve as Elementary Schools, Secondary Schools, Hospitals, or Emergency Facilities regardless of their size.
   
4. Alterations where the Change of Occupancy is from an "SE not required" use to an "SE required" use would require an SE regardless of the level of alteration.
   
5. New York State Level I and Level II Alterations without a Change of Occupancy to a higher Risk Category are excluded.
   
6. Non-Structural Components and Delegated Design are excluded.

Clearly, with this definition of the threshold structure, the vast majority of buildings and even the majority of constructed area will not require an SE; however, a hospital, for instance, would.  

In the recent discussion on SE licensure reference was made to complex structures. Given that what may be complex to one engineer may be routine to another what are examples of complexity that cause pause and why? See this link for background discussion.
https://collaborate.asce.org/integratedstructures/discussion/why-se-licensure#bm910d013d-ab5a-4c00-8ba5-2858ae527f59

Brian,

I really appreciate your thoughtful and cogent comments on this topic.  It seems like the "threshold" has to do with the importance of the building moreso than the complexity.  Buildings which use simple structural systems and facilitate ordinary use can bump into RCIII based on large occupancies, on the very apt logic that the stakes are higher and we should take greater caution in ensuring that only an extraordinarily unlikely event could cause failure.  A corrolary to Mitch's question that I'm still wondering about is: with importance-adjusted code requirements already in place, does it make sense for buildings which are equally complicated but of different sizes to require different qualifications?

As an alternative, here is a set of complexity-based criteria that I have pulled out of thin air (not necessarily advocating for this, just for discussion):

 - Buildings implementing performance-based design

 - Buildings using structural systems not explicitly addressed in ACI 318, AISC 360, or NDS

 - Buildings where nonlinear push-to-collapse analysis is required

 - Buildings detailed as special moment frame, special structural wall, or mass timber lateral force resisting system

 - Buildings with a structural aspect ratio above 1:6

 - Buildings with a horizontal irregularity as defined in ASCE 7

 - Buildings relying on sharing of lateral load among elements with relative stiffness of 5x or more between distinct lines of resistance

 - Buildings designed using semi-rigid diaphragms

 - Modifications to existing buildings more than 30 years old which fall outside of Level 1 or 2 Alteration per IEBC

 - Buildings subject to tornado loading or FEMA P-361 shelter design

One problem with this list: how would an owner know what kind of structural engineer to hire?

Though there can be many different types of complex structures, the term is colloquial with regard to SE Licensure.  In SE Licensure, we typically talk about a threshold structure as opposed to a complex structure, but the intent is similar. 

The goal of SE Licensure is to provide reasonable protection to the public in extreme conditions, and to be effective, a building department official needs to be able to objectively recognize which structures are beyond the threshold and should be designed by an SE.  In New York, our proposal with regard to buildings that require an SE is as follows:  

1. Buildings included in Structural Occupancy Category III or IV.
   
2. Buildings in Occupancy Category II that are greater than 60 feet (18.5m) in height, have a clear span greater than 150 feet (46.3m), are in Seismic Design Category D, or have a total occupant load of more than 1000.
   
3. Buildings that serve as Elementary Schools, Secondary Schools, Hospitals, or Emergency Facilities regardless of their size.
   
4. Alterations where the Change of Occupancy is from an "SE not required" use to an "SE required" use would require an SE regardless of the level of alteration.
   
5. New York State Level I and Level II Alterations without a Change of Occupancy to a higher Risk Category are excluded.
   
6. Non-Structural Components and Delegated Design are excluded.

Clearly, with this definition of the threshold structure, the vast majority of buildings and even the majority of constructed area will not require an SE; however, a hospital, for instance, would.  

In the recent discussion on SE licensure reference was made to complex structures. Given that what may be complex to one engineer may be routine to another what are examples of complexity that cause pause and why? See this link for background discussion.
https://collaborate.asce.org/integratedstructures/discussion/why-se-licensure#bm910d013d-ab5a-4c00-8ba5-2858ae527f59

In the recent discussion on SE licensure reference was made to complex structures. Given that what may be complex to one engineer may be routine to another what are examples of complexity that cause pause and why? See this link for background discussion.
https://collaborate.asce.org/integratedstructures/discussion/why-se-licensure#bm910d013d-ab5a-4c00-8ba5-2858ae527f59