Regarding the out-of-plain response, retrofit with buttresses obliviously provides an additional capacity in displacement (in non-linear range) as longer as the increasing of panel section (centroid coordinates changing). Nonetheless, it is relevant recognize a proper ratio between buttresses sequence and inner walls setting, in order to avoid out-of-plain arc-collapse mechanisms (the arc have to be enclosed within wall horizontal section dimensions).

Concerning no-ordinary masonry setting (rubble masonry.. etc..) tack masonry features is key. Distinguish in advance headers (or rowlock) and stretchers placement is essential. In reason of masonry type is recommended to design a reduction of buttresses span or supplementary wall reinforcements by traditional techniques.

The mechanical properties of masonry, currently used, have proved inadequate performance against heavy loads such as earthquakes or earth displacements. Researchers are thinking of additives to the slurry made by mixing cement, sand, and gravel with water. I know a university which tried to add poly(methyl methacrylate) which is a plastic that is dispersed within the matrix but the strength increased a little. In another university, the additive selected was a ceramic mixed with little α-methystyrene which unfortunately did not polymerize. My suggestion is to try elastomeric crosslinked polydimethylsiloxane as an additive which is really a tough polymer which withstands heavy shock loads, resists solvents, and does not crumble easily.

Dear All,

Thank you very much for the involvement and helpful suggestion.

Actually Pushover analysis was performed with the objective to assess the maximum level of lateral load at collapse, as well as to investigate in depth the mechanism of collapse that is activated. In this example, the analysis is performed by applying a uniformly distributed acceleration field over all the masses of the rigid components of the model.

The buttress is working under compression to contrast the lateral thrust of the walls that tend to buckle the model toward the inner courtyard. The collapse occurs by crushing of the central pillar, which is excessively stressed under combined compression and bending. There is also a significant shear damage at the foot of the buttress, indicating a high vulnerability of the buttress to shear failure.

Dear Nizar,

Where can I find more information on elastomeric crosslinked polydimethylsiloxane as an additive?

Dear Amir,

have you looked at strengthening methods with Fibre-Reinforced-Polymer sheets? They increase the out-of-plane resistance. Please see the attached paper. I hope this could be helpful. Regards. Luiza

Dear Amir,

To start with, below is attached a short reference about the physical & chemical properties of polydimethylsiloxane (PDMS). It is worth noting that when the surface of the moon was not fully understood, the first 2 astronauts to land on it were wearing crosslinked PDMS boots because it was even reliable against the "unexpected" had there been such a case. You know that the edges of windows are insulated by "silicone" paste against water entry to a house & once it is applied it serves for very long years. As for using it as additive, this is my idea & suggestion and I think that experimentation is needed to test that. Unfortunately, we do not have infrastructure at our university for such research. 

http://www.dowcorning.com/content/discover/discoverchem/properties.aspx

Dear Nizar,

Thank you very much for the contribution.

Dear Luiza,

Thank you very much for the enclosed document.

Hi Amir,

Alternatively you can use steel. A research project was devoted on steel strengthening techniques. Check the final report here:

http://bookshop.europa.eu/en/steel-solutions-for-seismic-retrofit-and-upgrade-of-existing-constructions-steelretro--pbKINA25894/

Let me know if you need any further clarifications.

Best regards,

George

Hi George,

Thank you for the shared documents. It is very interesting.

Using steel strengthening technique in case of masonry heritage buildings in some case could be questionable. 

The philosophy of restoration tends to give precedence to reversible type of intervention, in order to allow for possible future changes. This is right in principle, considering that appraisals are not invariably reliable; for this reason, too, it would seem beneficial to allow for the possibility of rectifying what has been done or applying improved techniques and materials as and when they are developed. Making good any damage is the primary task for the safety and continued survival of a property, and must be carried out in such a way as to restore the building to a satisfactory level in both regards. Given that in some cases repairs must be carried out with certain materials that were not used in the original structure, these interventions must be conducted so as to ensure the least possible departure from the original, and only provided they do not alter the basic features of the building in appearance and layout as well as those of its environs. It is possible, when necessary, to carry out works on the foundations, below ground and so forth. The difference between reversible and irreversible interventions, which have some minor limitations in common, is that in the case of irreversible interventions, greater compatibility between new and old materials and their durability is required.

Hi Amir,

I agree with your approach.

I thought of suggesting steel-based techniques to you based on the fact that they are completely (or to a high extent) reversible. In addition, alternations/improvements can also take place with minimum intervention.

Nevertheless, I acknowledge the fact that other approaches (e.g. FRPs) might be more applicable in this case, as others have commented. I generally believe that in order to decide, you should have first the whole picture of possible approaches.

Best regards,

George

Dear All,

A friend of mine is looking for the best research objectives for his proposal which is titled : 

Assessing the Efficacy of Retrofitting Techniques of Heritage Buildings in Terms of Cost, Performance Standards and the ability to meet the Demands of the Property Market in Canada.

Any suggestions for him? 

Regards,

Reza