1. INTRODUCTION

Extensive verification of the Archtec method of strengthening masonry arch bridges and the use of ELFEN Finite/Discrete Element (DE) analysis upon which the assessment and designs are based, including several full-scale tests, has previously been undertaken.

Consistent with other contemporary work on masonry arches and current assessment/design methods, the verification and testing which forms the current design basis for Archtec is focussed primarily on predictions and comparison of ultimate strength.

However, unlike other methods of arch assessment/design, DE analysis also allows the consideration of arch behaviour in the elastic range under service loads and although some analytical work has been undertaken to investigate this it had not been possible to fully verify it in the absence of suitable test data.

In the course of discussions with the Bridge Owners Forum (BOF) – Masonry Arch Subgroup, regarding the more widespread adoption of Archtec, the benefit of a Supplementary Load test to investigate the behaviour of unstrengthened and strengthened arches under service loads was identified. Following a meeting of the BOF with Gifford and Partners and Cintec on 5 September 2003 Pop Bottle Bridge in Lincolnshire was identified as suitable for such testing.

Pop Bottle Bridge had already been allocated for strengthening using the Archtec system and the Client, Lincolnshire County Council, kindly agreed that Supplementary Load tests could be carried out in parallel with the strengthening works.

This report describes the Supplementary Load tests that were undertaken in the first quarter of 2004 before and after strengthening the bridge with the Archtec system