This research program was initiated to examine the feasibility of assessingthe blast-resistant capacity of reinforced concrete (RC) slabs using the displacementbased design (DBD) method. In order to achieve this objective, five RC slabs weretested under real blast loads in the out-of-plane direction. One of the slabs was usedas the control unit to establish a baseline for comparison in terms of performance forthe other four slabs, which were strengthened with fiber reinforced polymer (FRP) andsteel fiber reinforced polymer (SRP). The explosive charge weight and stand-offdistance required to impose a given damage level were predicted by the DBD method.Test results showed that the blast loads were effectively estimated and the damagelevels observed from the field tests correlated well with the predicted levels. Inaddition, test results corroborated that the blast-resistant capacity of RC slabs can beeffectively increased by strengthening using FRP composites. The main conclusion thatcan be drawn from these tests using improvised explosive devices (IDE) is that RC slabsretrofitted on both sides have a higher blast resistance capacity than those slabsretrofitted only on one side. This paper discusses these experimental results alongwith the analysis steps used to predict the blast charge and standoff distance toimpose a given damage level.

A method for screening the durability of FRP bars under bending stress andimmersion in high pH solution at elevated temperature is described. Discussion of theneed for such a test, process variables affecting durability, determination of theappropriate bending radius and a description of the test method are shown. Testresults from a series of eight production runs varying only one of the processes relatedvariables, glass fiber supplier, are shown. Fiber sizing chemistry for the fiber/resin/production system is key to better durability of GFRP rebar. The bending stressdurability test method helps reveal FRP bar system performance for differentconstituent materials and offers a more practical method for evaluating alkalinedurability of GFRP bars. The method is intended as an indicator of durabilityperformance and not a definitive evaluation.

The efficacies of the Near Surface Mounted (NSM) and Externally BondedReinforcing (EBR) techniques for the shear strengthening of rectangular cross sectionRC beams are compared. Both techniques are based on the use of carbon fiberreinforced polymer (CFRP) materials. The NSM was the most effective technique, andwas also the easiest and fastest to apply, and assured the lowest fragile failure modes.The performance of the ACI and fib analytical formulations for the EBR shearstrengthening was appraised. In general, the contribution of the CFRP systemspredicted by the analytical formulations was larger than the values registeredexperimentally. The capability of the De Lorenzis formulation of predicting thecontribution of the NSM technique for the shear strengthening of RC beams wasappraised using bond stress and CFRP effective strain values obtained in pulloutbending tests. This formulation provided values 61% lower than the values obtainedexperimentally.

Tensioned carbon fiber reinforced polymer (CFRP) strip method or Outplate-methodTM was applied to the 28 years old reinforced concrete (RC) box girder bridge inorder to rehabilitate and increase the load capacity of the bridge. The Chofu Bridge hadbeen deteriorated by 28 years of heavy traffic and had many cracks on the underside ofthe main girders. Before and after the CFRP application, on-site load tests of the bridgewere conducted using a 45 ton-weight vehicle. Results of the tensioned CFRP stripapplication to the bridge girders proved effective to reduce the stress in the reinforcingbars and to reduce crack widths.

This paper presents the results of an experimental/analytical study aimingat obtaining a clear understanding of the underlying mechanisms of the shearstrengthening of reinforced concrete beams with fibre reinforced polymers (FRP).Through the definition of the generalised constitutive law of a bonded FRP sheet, of thecompatibility imposed by the shear crack opening, and of the appropriate boundaryconditions depending on the strengthening configuration, analytical expressions of thestress field in the FRP sheet crossing a shear crack are obtained. These expressionsallow to easily define closed-form equations for the effective strength of FRP strips/sheets used for shear strengthening, as function of both the adopted strengtheningconfiguration and some basic geometric and mechanical parameters. The FRPcontribution is then added to those of concrete and steel. The equations accuracy hasbeen verified through correlation studies with experimental results obtained from theliterature and from laboratory tests on purposely under-designed real-scale beamspecimens, strengthened with different FRP schemes.