In-plane Stiffness of the Prussic Caps

Prussian caps (flat masonry arches) were used very often as a masonry slab structure in living houses on the verge of the century. While transfer of the vertical loads is clear, for the in-plane acting horizontal loads (wind, earthquake, etc.) remain several doubts to be cleared. Floor slab is commonly assumed as an infinitely stiff membrane which performs force transfer and distribution to the vertical bracing elements. In this work, we have tried to analyze: a.)stiffness of the Prussian caps and their ability to withstand the in-plane loading ; b.) meaning of the strengthening with an additional thin concrete slab ; c.) stiffness and load distribution among the two systems.