Interface Behaviour in FRP Plates Bonded to Concrete: Experimental Tests and Theoretical Analyses

Simplified models for simulating FRP-to-concrete interface behavior are introduced and empirical relationships are utilized for their calibration. Moreover, the results of pull-out tests on FRP-to-concrete joints are presented. They are utilized in calibrating a bilinear shear-stress-to-interface-slip relationship by means of an inverse identification procedure

Flexural check at high temperatures of reinforced concrete bridge decks strengthened with EBR-FRP

In this paper the thermo-mechanical behaviour of RC bridge decks strengthened with externally bonded FRP laminates is investigated by considering environmental conditions responsible of thermal states different from the normal ones. A parametric analysis is performed by varying the slab thickness, the FRP reinforcing percentage, the type of fibre and the thickness of the protection layer. The results are given in terms of ultimate bearing capacity of the slabs, which allows individuating the conditions responsible of premature FRP-to-concrete debonding or temperature levels greater than the glass transition temperature of the adhesive

STRUCTURAL FIRE SAFETY OF EXISTING STEEL BUILDINGS, Possible general approach and application to the case of the intumescent coatings

The fire safety of the existing structures is very important from the socio-economic point of view and has high social impact for civil, industrial, and commercial buildings. The verification of the minimum fire resistance of civil structures is done through some regulations, drafted to ensure occupant and rescue teams safety as well as a limited structural damage. These national fire rules are not always easily applicable to existing buildings. The purpose of this paper is to provide guidance about the structural analysis of existing buildings exposed to fire, with particular reference to steel buildings protected with intumescent coatings

soil structure interaction effects on the seismic performances of reinforced concrete moment resisting frames

Abstract The paper investigates the influence of Soil-Structure-Interaction (SSI) effects on the seismic performances of 2D reinforced concrete (RC) moment resisting frames (MRFs), which were investigated by means of non-linear dynamic analyses. The goal was pursued by means of a parametric study in which (1) the soil properties, (2) the modelling technique of the SSI effects, (3) the seismic design level of the structures were varied. The soil classes suggested by Eurocode 8 were taken as reference to define the mechanical properties of soil. As concerns the SSI modelling, both a sub-structures approach and a direct approach were considered. Finally, structures of 4 and 8 floors designed for vertical loads only or according to the Italian regulations for constructions (NTC-08) were considered. RC-MRFs founded on soft soils were considered, because SSI effects on the seismic response are expected higher. The study shows that SSI affects the seismic demand in terms of maximum base shear and maximum inter-story drift ratio with different significance depending on the modelling approach

HIGH Tg FRP & CEMENTITIOUS ADHESIVE, Potential benefits in fire for NSM FRP strengthened reinforced concrete beams

Near surface mounted FRP strengthening is potentially less prone to damage due tofire exposure than externally bonded FRP reinforcement (EBR), provided that: (a) an FRP strengthening material with high glass transition and decomposition temperatures (Tg andTd, respectively); and (b) a bonding agent with low thermal conductivity and good thermal stability, are used. This paper presents a project undertaken on a specific high Tg and cementitious adhesive bonded NSM FRP strengthening system. Dynamic Mechanic Analysis (DMA) and Thermogravimetric Analysis (TGA) performed on the novel high Tg commercial CFRP bar yielded a Tg value of 220°C (based on  peak) and Td of about 360°C. Thermal conductivity tests were also performed on the cementitious grout. The results were used to better explain the failure modes of NSM FRP strengthened reinforced concrete beams at elevated temperature. The paper highlights the importance of understandingthe thermo-mechanical properties of the various constituent materials for improving the performance of FRP strengthening systems in fire

INVESTIGATION ACTIVITY ABOUT A COLLAPSED STEEL STRUCTURE SUBJECTED TO A REAL FIRE, Fire scenarios and structural behaviour of a real steel structure

The paper describes the behaviour ofa real steel structure collapsed under a fire event. 3D structural analyses were performed with SAFIR program (J-M Franssen, 2005). Different modellingare implemented with some fire load models and analyses of thebehaviour of the whole structure. The main purpose of this work was to investigate the failure types of a warehouse structure under fire conditions. Different fire conditions were applied to the steel frame sections, with ISOcurve (ISO EN 834-8:2002) and zone model approach. The analyses show that with unprotected steel sections, horizontal structures are more critical than columns. Trough applying a performance basedapproach,structure has 30 minutes of fire resistance