Seismic Behavior of Reinforced Concrete Roofs on Masonry Buildings


Abstract eng:
The 2016 Central Italy earthquake has demonstrated the seismic vulnerability of historical masonry buildings which are typical of the small towns of that area. The majority of the houses were seriously damaged and a great number of them totally collapsed causing the loss of many lives as well as economic and cultural losses. The lack of awareness and of proper retrofit intervention led to a disruptive scenario. Among many collapse mechanisms that have been detected, the one due to reinforced concrete roofs has been the most discussed. Firstly because of its dangerousness, secondly because the replacement of old wooden roofs with reinforced concrete roofs is indeed a widespread retrofit intervention since it is highly recommended by national codes. The aim of this intervention is to improve the robustness of the structure achieving the so called “box-like behavior”. A concrete roof is able to distribute the loads more evenly and to connect the walls to each other and finally to avoid the slipping of the beams that was common for masonry buildings with a wooden roof. However, in most cases, the retrofit intervention, done by private owners with the belief of making their house safer, turned out to be destructive. The reason of this failure was the ineffective connection between the top beam ring and the masonry walls that should have been consolidated before the intervention. Thus, the significant increase of stiffness and load at the top of the buildings led to the collapse of walls and to the overturning of concrete roofs, which remained undamaged. Fig.1 shows the effects of the Central Italy earthquake in a building retrofitted with a reinforced concrete roof. It can be seen the clear detachment of the roof that collapsed under the seismic action disrupting the masonry walls and then overturned. It is also clear the poor quality of the masonry that could not bear such a high load.

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Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
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Text je chráněný podle autorského zákona č. 121/2000 Sb.



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 Record created 2017-01-18, last modified 2017-01-18


Original version of the author's contribution as presented on USB, paper 5014.:
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