“Integralization” with new UHPC decks for existing motorway bridges

Abstract

The efficiency of the technique of strengthening existing structures using Ultra High Performance Fibre Reinforced Concrete (UHPFRC) has been investigated in this study. The uniaxial stress-strain relationship in tension and the compressive strength characteristics have been determined by direct tensile and compressive tests respectively. These results have been used for the constitutive modelling of UHPFRC. The model in tension is consisted of several linear parts, including strain hardening followed by a significant post crack energy absorption softening branch. Finite Element method has been used for the modelling of strengthened reinforced concrete beams with UHPFRC layers and a parametric study has been conducted on beams strengthened with UHPFRC layers and jackets. The efficiency of this technique is highlighted and the performance of strengthened beams with UHPFRC layers is compared to respective specimens strengthened with additional concrete layers reinforced with steel bars. by superior mechanical properties. Kang et al. (2010) and Yoo et al. (2013) examined the effect of the steel fibers amount on the flexural strength of UHPFRC and it was found that the flexural strength increased with the fiber volume ratio while the ductility was decreased. Kang et al. (2010) presented an inverse analysis to determine the tensile fracture model of UHPFRC and a trilinear tensile fracture model of UHPFRC tensile softening model is proposed.

Strengthening of reinforced concrete beams using ultra high performance fibre reinforced concrete (UHPFRC)

“…The behaviour was considered linear up to a tensile strength of 11.5 MPa and, after the end of the elastic part, the stress-strain presented in Fig. 7 was adopted for a characteristic size equal to 2mm [31]. This model is in agreement with the model proposed by Habel et al [27] and adopted by Bruhwiler [26] and Noshiravani and Bruhwiler [28].…”

“…The numerical results (IB num ) are compared to the respective experimental for (IB exp ) and the results are presented in Fig. 3 [31].…”

“…The findings presented in the previous studies are mostly focused on the mechanical properties of UHPFRC, and there are other published studies on strengthening applications [24][25][26][27][28][29][30][31]. Farhat et al [24] examined beams strengthened with UHPFRC strips.…”

UHFB‐Overlay auf Fuß‐ und Radwegbrücke Karl‐Heine‐Bogen in Leipzig

“…On an area of approximately 160 m 2 , 6.5 m 3 of UHFB were casted within one day. Aufbauend auf den Erfahrungen im Rahmen eines Forschungsprojekts [4] und eines Pilotprojekts [6] wurden durch das planende Ingenieurbüro KHP Leipzig die zu erreichenden Festigkeiten festgelegt, wobei die Prüfungen nach der Schweizer UHFB-Richtlinie [7] zu erfolgen hatten:…”

The use of Ultra High Performance Fibre Reinforced cement-based Composites in rehabilitation projects: a review

“…Three different configurations were analyzed in [28]. UHPFRC layers were added a) in the tensile zone, b) the compression zone, and c) as a three-side UHPFRC jacket.…”