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Pre-stressed unbonded retrofit (PUR) CFRP strengthening of steel structures is becoming a common method of strengthening metallic structures. This paper presents a comprehensive study on the use of the PUR CFRP-strengthening method for strengthening a steel bridge in Melbourne, Australia. Finite element analysis is performed in this study to model the entire bridge and the strengthened element, and the model is validated using actual on-site measurements which showed the stress developments of two girders before and after strengthening when a fully loaded truck passed over the bridge. A parametric study is performed to investigate the stress development of steel girders strengthened with the PUR system under different girder-deck levels of rigidity. The results showed a perfect match between the finite element modelling and actual measurements, and the effectiveness of the PUR system under critical conditions such as different girder-deck stiffness connection levels. [ABSTRACT FROM AUTHOR]

Highlights • A historically significant metallic bridge in Australia was strengthened using CFRP composites. • Laboratory tests were conducted to develop nonprestressed bonded and prestressed unbonded systems. • Installation complexity and performance of the two developed systems were compared. • Short-term truck loading results and long-term wireless sensor network measurements are discussed. • Diurnal temperature changes caused significant thermal-induced stress cycles in the nonprestressed bonded system. Abstract This paper summarizes the strengthening of a historically significant 122-year-old roadway metallic bridge using nonprestressed bonded carbon fiber reinforced polymer (CFRP) plates. Prior to the bridge strengthening, sets of laboratory tests were conducted to characterize the mechanical properties, glass transition temperature, and CFRP-to-steel bond strength of two different epoxy adhesives (linear and nonlinear) commonly used for structural retrofitting. Furthermore, the field application complexity, as well as the short- and long-term efficiency of the developed nonprestressed bonded system, was compared with the existing flat prestressed unbonded retrofit (FPUR) system. Short-term measurements, including sets of truck-loading tests performed before and after strengthening, demonstrated that the tensile stresses were reduced by approximately 15% and 44% in the bridge cross-girders after strengthening by the proposed nonprestressed bonded and FPUR systems, respectively. The long-term measurement results, obtained from a wireless sensor network (WSN) system installed on the bridge, revealed that because of the mismatch of the steel-CFRP thermal expansion coefficient, diurnal temperature changes can cause significant thermal-induced stress cycles in the nonprestressed bonded CFRP plate. These diurnal cyclic stresses must be considered in the design of bonded CFRP strengthening solutions. [ABSTRACT FROM AUTHOR]

Highlights: [•] Sand to cement ratio can affect properties of dune sand concrete (DSC). [•] Dune sand grain with size smaller than 175μm (VFP) can affect the hydration. [•] VFP increases strength of DSC due to nucleation and pozzolanic effects. [•] DSC and river sand concrete have comparable engineering properties. [•] Australian dune sand can be used as fine aggregates for making concrete. [Copyright &y& Elsevier]