An comprehensive new online course is another milestone achievement from the Quake Centre that promises real benefits...
It's a self-paced online course that should offer sound advantages to the sector.
It aims to improve earthquake resilience by facilitating practical capacity assessment of reinforced concrete frame buildings.
Currently under construction, the online course will help structural engineers to understand and carry out strength hierarchy assessment, and show users how to practically identify the weak structural elements at the beam-column joints of multi-storey reinforced concrete buildings.
This is an important part of detailed structural assessment before any retrofit/strengthening application can be carried out and is expected to contribute partially to the general earthquake resilience, assessment and strengthening efforts to be undertaken over the next 15 years .
Overseeing the development of the online course is Quake Centre Research Engineer, Dr. Ali Sahin Tasligedik, who says this very specialized topic is intended, “to make life easier for structural engineers working in the field.”
“They’ll learn and apply a method to easily identify and evaluate which component of a building (beam, column or joint) is in trouble and what could potentially fail under a given seismic demand.”
Considering the computation power and technical staff available to many construction companies, it’s just not possible to carry out the detailed structural analysis of every individual structure (built before or after the updated earthquake codes introduced in the 1970’s).
Given the sheer number of the existing NZ building stock to be assessed, it might take 20-30 years to carry out such analysis but this time-frame can be reduced significantly by using simplified methods requiring less computational effort such as the one presented in this course (as well as others, e.g. NZSEE 2006 seismic assessment guidelines).
The taught method would essentially act as a ‘filter’ to detect whether more detailed future analyses are necessary or not. It can be completed off-site by using the input from the building drawings and without the need for an advanced finite element structural analysis software.
“Only spreadsheet software and basic reinforced concrete knowledge are required in order to carry out the method, which would be at a fraction of the cost,” says Dr Tasligedik.
The online course - entitled ‘Strength Hierarchy at Reinforced Concrete beam-column joints and global capacity’ leads onto Dr. Tasligedik‘s ongoing collaborative work/updates into the ‘Design of FRP (fibre reinforced polymer) for RC (reinforced concrete) Beam-Column Joints Using the Strength Hierarchy Assessment Method.
Dr Tasligedik explains, “given that the structural stability of a building during seismic activity is strongly dependent on the integrity of the RC beam-column joints, we should be able to calculate the capacity of the weakest element at every beam-column joint in a frame building – before the damage occurs.”
Once determined, FRP’s can be used to ‘shore up’ compromised beam-column joints, much like a sportsperson bandages a knee to prevent injury and increase weight bearing capacity during exercise or a weightlifter wears a confining belt at the waistline to prevent muscle tear during heavy lifting.
With the technical theory, interactive examples and case studies to work through, this new Quake Centre online course is intended to compliment engineers’ current understanding into the behaviour of RC frame buildings and further guide their interpretation of crack formation at the joints, columns and beams.
“Content-wise there’s 5-6 days’ worth of material to get through on the couse - depending on your learning speed,” says Dr Tasligedik.
“There’s no time limit, you can go at your own pace. Once through the initial learning curve, having grasped the method and with building data input collected, it can be applied to a multi-storey building in just 1- 4 days.”
The benefits of being able to apply this simple, yet accurate, method to industry has been acknowledged at both an international and local level through positive feedback on the course over a two-year peer review.
“Strength hierarchy assessment of multi-storey RC buildings is a part of the NZSEE 2006 guidelines, with all earthquake prone buildings in New Zealand required to be assessed for earthquake resilience within the next 5 - 15 years,” adds Dr Tasligedik.
“Being able to analyze a building with this method to assess where the earthquake damage would likely occur has the potential to speed up the process for most RC buildings by reducing the number of buildings that require more detailed assessment procedures.”
This is particularly poignant in light of the recent 14 November 2016, 7.8 magnitude Kaikoura earthquake, that caused damage and in some cases closure to multiple multi-level buildings in New Zealand’s capital city Wellington, some 577.5 km to the North of the epicentre.
Should the predicted ‘big one’ rattle right under Wellington city high-rises, identification of the structural weaknesses in buildings with the help of robust scientific methods, like the one offered through this Quake Centre online course, is paramount.