Masonry properties for assessing arch bridges

A research programme to examine the strength of masonry arch bridges is being undertaken by the Transport and Road Research Laboratory (TRRL). The aim is to provide the basis from which new or revised methods of assessing their traffic load capacity can be developed, to supplement or replace the commonly used MEXE method. New analytical techniques have been developed and a series of load tests to failure at full and model scale have been carried out to provide calibration data. The new analytical techniques need more information about material properties than does the MEXE method, for example the compressive strength and elastic modulus of the arch ring brickwork or stonework. The purpose of this contract was to draw together currently available advice on estimating or measuring masonry properties and to modify it where appropriate with reference to the stress conditions found within arch bridges, in order to provide guidance to users of the new assessment methods. In this report, work carried out by CERTI Consultancy and Testing Services, Department of Civil Engineering and Building Science, University of Edinburgh, under contract to TRRL is described. It covers: (1) the factors affecting the compressive strength of masonry which are relevant to arch structures; (2) a review of available information from the literature and from codes of practice relating to the estimation of compressive strength and stress-strain relationship; and (3) practical recommendations made arising from the work described.