FATIGUE PERFORMANCE OF FRP AND RADIAL-PIN REINFORCEMENT ON MULTI-RING MASONRY ARCHES Clive Melbourne, Adrienn Tomor School of Computing, Science and Engineering, University of Salford

Background and context Many arch bridges need repairing and strengthening due to old age and increasing traffic loading. Current reinforcement techniques involve reinforcement at the intrados. Not much information on the long-term behaviour of strengthening techniques is available. As a consequence of old age and increasing traffic loading many arch bridges need repairing and strengthening. Current techniques involve reinforcement at the intrados. Performance of strengthening techniques has been mainly tested under static loading but their long- term behaviour is not well understood.

Loading Dead load Cyclic loading Static loading Live load

3M SPAN ARCHES (2 RINGS)

5M SPAN ARCHES (3 RINGS) under static and cyclic loading.

Test series FRP reinforcement FRP + reinforcement + Radial pinning Glass fibre sheet Steel studs

FRP reinforcement Glass fibre sheet (50/50 wave) was applied to the intrados 1.As the weakest form of composite. 2.To least influence the behaviour of the arch.

TEST RESULTS FRP reinforcement

Ring separation (Side) Four hinge mechanism Without FRP With FRP FRP reinforcement Static loading Ring separation

Ring separation (Side) Four hinge mechanism Without FRP With FRP FRP reinforcement Static loading Load 28kN 29kN Load 20kN 25kN 3m Span 5m Span Load 30kN 72kN

FRP reinforcement Cyclic loading Without FRP With FRP Ring separation

With FRP Ring separation Without FRP Ring separation FRP reinforcement Cyclic loading Load 18kN 12kN 14kN 26kN Load 26kN 20kN 3m Span 5m Span

FRP reinforcement summary RFP reinforcement reduced the load capacity under static loading by up to 30%. increased the load capacity under cyclic loading by at least 20%. can change the mode of failure. Delamination did not occur. FRP reinforcement reduced the load capacity under static loading by up to 30%. FRP reinforcement increased the load capacity under cyclic loading by at least 20%. The presence of FRP sheet can change the mode of failure of the arch. By preventing the formation of hinges, shear stresses are increased and can cause failure. Delamination occurred in limited areas but was not responsible for failure.

TEST RESULTS Radial pinning

Applied to FRP reinforced arches after ring separation occurred. Arches were drilled radially and Ø10mm steel studs installed in pairs. Cyclic loading was resumed Radial pinning

Failure mechanism

Radial pinning Modes of failure FRP Load 26kN FRP + Pin Load 18kN FRP FRP + Pin 3m arch Sliding Pulling out of pin 29kN 19kN

Radial pinning failure mechanisms Ring separation changes the stress distribution within the arch ring. Radial pins can fail in a number of different ways: Flexural stresses Longitudinal shear stresses a) shear in pin b) Bearing/crushing c) Plastic hinge d) Tension in pin e) Pull out

FRP reinforcement can reduce the load capacity of multi-ring arches. FRP reinforcement improved the fatigue performance. Radial pinning with FRP reinforcement reinstated and increased the original load capacity. Conclusions

END