CRUPE Seismic Testing Stage 2 (i.e. Dynamic and Cyclic Response of a Full-Scale 2-storey CRUPEFrame cold-formed light steel structure with CRUPE Protect, Finish & SL Floor cladding) was conducted on August 12, 2014 at the Structural Engineering Laboratory in Bogazici (Bosphorus) University, Istanbul, Turkey.  This is one of the most advanced Universities in the world for testing dynamic structural response and at the forefront of seismic research which has the additional benefit of optimising the amount of steel used in the construction of seismic efficient buildings saving weight, time, lives and of course cost in construction.
 
The primary purposes of the second stage of our seismic test was to observe the change in dynamic behaviour of the Stage 1 light steel structure after the walls and floors were built up with CRUPE materials and how much contribution is made by these CRUPE materials towards the total lateral load-bearing capacity of the building. We also wanted to observe the ultimate limits of our system and find the weakest links for failure under extraordinarily high loads.
 
The first part of Stage 2 were the dynamic tests where, in addition to ambient vibration measurements, the structure was dynamically loaded via an eccentric mass shaker located on top of the building (i.e. forced vibration test).  Data collected in this part is used to obtain modal frequencies, mode shapes and modal damping ratios for the Stage 2 structure. The initial data analysis shows that the addition of CRUPE material on the light steel static structure causes a significant increase in damping, which leads to further mitigation of earthquake effects on the whole structure with reduced displacement and vibrations. These initial results show the frequency of the whole structure increased from 3Hz to 13 Hz between Stage 1 and 2, and there has been a considerable rise in lateral stiffness.
 
 (See video for the building in resonance during Dynamic Tests)
 
The second part of the experiment comprised of cyclic tests where the structure was pushed and pulled from side to side via actuators located on the 1st and 2nd floor levels. This was to determine key parameters to be used in seismic design of future CRUPE buildings such as lateral load bearing capacity and ductility. Again, the initial analysis shows that the addition of CRUPE materials increases the load bearing capacity of the steel structure by approximately 4 times (400%). This can be compared with traditional cladding materials used to close steel structures which generally have far less load bearing capacity than CRUPE.  These results are also consistent with seismic testing we have been undertaking with another independent advanced engineering University in China.
 
The inter-storey drift at the yield point was measured to be around 2%, therefore the ductility of CRUPE structure is extremely high and it can take approximately twice the displacement of an ordinary reinforced concrete structure before failure under earthquake conditions.
 
Not withstanding the anchors pulled out and the building was displaced at 53mm displacement at the 1st floor level, CRUPE material was intact and no significant cracks were observed on the building. 
 
When the actuator piston reached its full stroke at 100mm (this is an unrealistically high displacement which will not occur in any real earthquake) at the 1st floor level, significant cracks occurred on the walls but there was no collapse of any critical member in the building meaning that the building would remain standing with cracks and the inhabitants presumably remaining unharmed inside.
 
The final results of these tests are still under technical analysis and the corresponding reports are expected to be published over the next weeks. Please contact Mr. Gunes Goler (gunes.goler@crupe.com) for any enquiries on CRUPE seismic testing and how this may be used in construction projects under planning in seismic areas or simply to further optimise (minimise) the amount of steel used within the construction of structurally efficient buildings around the world (reducing the time and cost of your construction project).