1,721,020 research outputs found
L’attività del DICEAA nella ricostruzione post sisma 2009: alcuni esempi e applicazioni
No full text
Studi preliminari finalizzati alla redazione di istruzioni per l’impiego di calcestruzzi ad alte prestazioni, CNR-DT 209/2012
No full text
Effetto della variazione dei materiali sulla resistenza e sulla duttilità delle strutture esistenti in calcestruzzo armato
No full textTwo-heads brick masonry walls strengthened by basalt and glass chopped fiber mortar: Effect of bed joints and coating reinforcements
Full text linkIt is urgent finding strengthening systems for masonry structures located in seismic areas. This paper studies the effect of chopped fibers embedded in a cementitious mortar to be used as a strengthening system for two-heads brick masonry panels subjected to diagonal compressive forces. The strengthening system provides the use of two types of chopped fibers dispersed in the mortar matrix, i.e. a glass fiber reinforced mortar (GFRM) and a basalt
fiber reinforced mortar (BFRM). The retrofitting composite material is disposed in three different ways: (i) the reinforced mortar is placed within the mortar joints of masonry panel; (ii) the reinforced mortar is disposed on both external surfaces of the masonry panel, but the mortar joints are in plain mortar; (iii) the reinforced mortar is placed both within the mortar joints and as a double reinforcing system on the external surfaces of each masonry panel. Experimental results show that in all the three cases the use of fiber reinforced mortar enhances both the shear strength and the post-peak capacity of the two-heads brick masonry panel. The most suitable behavior is related to panels reinforced with mortar both within the joints and as external reinforcing system. From the comparison between GFRM and BFRM it is shown that the best performance is related to basalt fibers mortar, that is also the most sustainable one. Authors always recommend the use of dispersed fibers within the mortar matrix, as it stands as effective strengthening system for new and existing masonry structures, above all when they are located in areas characterized by seismic hazard
One-head masonry panels reinforced with industrial-waste fiber reinforced mortar: Investigating the effect of bed joints and coating reinforcement in the diagonal compressive behavior
Full text linkExperimental and numerical investigations on timber-concrete connections with inclined screws
No full textIn new and existing buildings, it is important that floors are sufficiently strong and stiff in plane. In comparison with pure timber floor systems, timber–concrete composite structures are often used as floor solutions to better combine acoustic separation with both greater load-carrying capacity and increased stiffness, also resulting in significant improvement of the serviceability vibrational comfort. The choice of a structurally effective yet inexpensive shear connection between the concrete topping and the timber joist is crucial to make the composite floor a viable solution that can compete with reinforced concrete and steel floors. The use of inclined screws to connect the timber beam to the concrete topping represents a possible solution to maximize the slip modulus of
the connection and, at the same time, to keep the construction cost within acceptable values. In this paper, the mechanical behavior of such a type of timber to concrete connection is explored via experimental pushout tests and numerical investigations. The specimens tested were made of an inner timber block connected to two outer concrete slabs by means of two 8 mm diameter screws per side. To reproduce the timber flooring used in real practice as permanent formwork for the placement of the concrete topping, an OSB layer was introduced between the timber block and the concrete slabs of the specimens. Experimental results were statistically assessed to compute the mean slip moduli and the characteristic values of the shear strength. A mathematical model of an inclined elastic beam on an elastic foundation capable to provide the slip modulus of the system was developed. The dependency of the slip modulus upon the screw inclination and the interlayer flooring thickness was also investigated. The accuracy of the theoretical results was assessed through comparisons with experimental results
On the Development of Innovative Ductile Mortars for Structural Strengthening in Seismic Areas
No full text- …
