Performance-based Optimisation of Resilient Moment Resisting Steel Structures

Lead Research Organisation: University of Sheffield
Department Name: Civil and Structural Engineering

Abstract

The overall aim of the proposed project is to develop a new generation of resilient moment resisting steel structures that are cost effective and have better structural performance under accidental and extreme loading events such as strong earthquakes and explosions. This will be achieved through the following objectives:
1) A critical literature review looking into current performance-based design and optimisation methods for moment resisting steel frame structures.
2) Detailed finite element modelling using programs such as OPENSEES and ABAQUS to investigate the nonlinear seismic response of typical moment resistant structures and determine acceptable design criteria to satisfy different performance levels.
3) Develop a novel performance based design framework, based on the concept of uniform damage distribution, for more efficient performance-based design of moment resistant frames.
4) Extensive analytical study and sensitivity analysis to find out the key performance parameters and develop a simple performance-based design methodology for practical design purposes.
5) Comparison of the structural weight, whole-life cost and seismic performance of optimum and conventional design structures to demonstrate the efficiency of the proposed performance-based optimisation method through a number of practical design examples.

Publications

10 25 50

Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509735/1 01/10/2016 30/09/2021
1965962 Studentship EP/N509735/1 26/09/2016 25/07/2020 Thomas Horton
 
Description I have started this award by looking at the performance of steel moment resistant frames under seismic excitation's. The beam-column connections of these steel moment frames under non-linear dynamic effects are a significant contribution to the performance based design of steel moment resistant frames.

There is a need to develop a new generation of beam-column connections which will be able to provide the designer with any specified characteristics in order to achieve a specific performance based design criteria. The three most important criteria are: Immediate Occupancy, Life Safety and Collapse Prevention of the steel moment frame. These criteria are defined based on the deformations of the buildings, hence a new bespoke connection is needed that can provide these requirements.

Additive printing or 3D printing is a new and developing idea that could provide potential structural uses in the future. One aspect of this research will look at what the potential benefits an additivly printed connection could give on the performance of steel moment resistant buildings.

Another significant area discovered is how the widely accepted RBS connection currently used in seismic resistant steel moment frames can be be optimized in every part of the building in order to provide an optimal performance based designed frame. The RBS properties of a frame can effect the buildings performance. Currently three parameters effect the geometry of these RBS connections. The research will look at how a frame can be optimized using these geometries to produce a more seismic resistant frame.

The current Ibarra-Krawinkler model is limiting. It only can predict general cases for RBS connections. I am looking at proposing a new improved model which takes into account the geometrical parameters of the RBS connection.

New design equations have been proposed which can predict the key seismic design parameters of any RBS connection with any combination of the three geometries which define the RBS geometry. These design equations can be found in my first publication.

A deep learning neural network has been used which will predict the modified Ibarra-Krawinkler parameters required for advanced non-linear dynamic analysis in specialist earthquake engineering programs. This deep learning network has been trained with over 1400 different full cyclic responses of RBS connections (over a variety of RBS geometries) and provides accurate and reliable predictions of any beam size and RBS geometry (within the limits of the model) for modified Ibarra-Krwinkler models. The outcomes have shown that the RBS of the connection does effect and change the parameters which define the cyclic behavior.

The RBS geometry has clearly been demonstrated to effect the response of a system at the local level. A proof of concept at the global level (i.e. frame level) is being implemented to show how a full RBS steel moment resisting frame can be improved by optimizing the RBS geometries at all locations in the frame.
Exploitation Route I will have hoped to have laid down the foundations for how additive printing of bespoke structural connections will be invaluable in steel moment frames. Therefore, making a string argument for how and why the development of bespoke 3D printed connections is necessary. A potential future project could be the development of structural additively printed connections.

If RBS connections can be optimized for a performance based design, this can be significant in improving and retrofitting buildings in a cost effective way.

My work has laid novel foundations for investigating the behavior of RBS connections. More detailed work needs to be carried out into investigating the global response at the frame level. This also leaves the possibility of including the possibility of proposing additive printed connections instead of RBS connections to enhance the frames performance. Can the frames performance be significantly improved if we can have any connection response we want by using additive manufacturing of a connection.
Sectors Construction,Other

 
Description My potential findings can be significant for developing countries who want to improve the performance of existing steel framed buildings. Where instillation of dampers and other retrofitting seismic methods care too costly, improving the performance of buildings by trimming specific areas of the beam away, making each RBS connection specific to its connection location, can significantly improve the structure. On the other hand, showing the potential benefits of structural additively printed connections for seismic resilient buildings for the 21st century is a big step forward in structural engineering. Highlighting the benefits of such connections shows the need for future research that needs to be conducted to investigate this potential area. My findings show that local response of the RBS connection in steel frame buildings is dependent on the RBS geometries. Therefore, when designing frames with RBS connections the profiling of the RBS should be taken into account. Functions and equations have been proposed through deep learning neural networking to produce functions which can predict the parameters for a modified Ibarr-Krainkler model which predicts the cyclic performance of an RBS connection.
First Year Of Impact 2019
Sector Construction,Other
Impact Types Societal,Economic

 
Title Working on producing an improved Ibarra-Krawinkler model 
Description Trying to improve the Ibarra Krawinkler model for predicting the responses to RBS beam-column connections 
Type Of Material Computer model/algorithm 
Year Produced 2018 
Provided To Others? No  
Impact This could be an improved model for predicting the behaviors of RBS beam-column connections 
 
Description 2nd talk or presentation about my PhD research 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Study participants or study members
Results and Impact Presentation about my work and improving the Ibarra Krawinkler equations and some suggestions for future work
Year(s) Of Engagement Activity 2018
 
Description Presentation to the Seismic research group at Sheffield Universit 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact First presentation on my research and what I proposed for my PhD. Some interesting discussions about the potential for 3D printed connections as well as the optimization of seismic resilient structures
Year(s) Of Engagement Activity 2018