ARCHTEC

The heart of the system is the Cintec Anchor and reinforcement together with Gifford and Partners, specialist bridge engineers using “Elfren”, Rockfield Software Ltd’s Finite/Discrete Element software, to mathematically model the masonry structure.

Archtec is the market leader in the structural strengthening of exiting bridges. It has inspected and reported on the strength of over 200 bridges and physically strengthened more than 120 bridges in Tasmania, Caribbean, North America, India, and Europe and throughout the United Kingdom since 1999.

Archtec was originally devised to meet the latest European bridge code in 1999 when all trunk road bridges should have complied with the 40 tonnes rating. A series of tests were undertaken at the Transport Research Laboratory with full size bridges using guide philosophy laid down in BA54/94 – Load Testing for Bridge Assessment.

Following two highly successful tests in the laboratory when two previously un-strengthened arches were strengthened to over 40 tonnes using the Cintec reinforcement and confirming the accuracy of the Elfren Discrete Element diagnostic analysis, it was decided to further test the Archtec system for serviceability on the Pop Bottle Bridge in South Lincolnshire. This skewed two span brick arch bridge was originally calculated using the MEXE analysis to be 13 tonnes. A Supplementary Load test was applied to demonstrate the efficacy of the Archtec strengthening system under service loads and to further validate the use of the Elfren Finite/Discrete Element analytical method.

The load tests were carried out in two stages, before and after strengthening, and were undertaken using the guiding philosophy laid down in BA 54/94 – Load Testing for Bridge Assessment.

The conclusions drawn from the results of the two test loads, on the bridge in its un-strengthened condition and after being strengthened using Archtec, were that the Cintec reinforcement system was stressed under working loads and is contributing to the bridge stiffness. Also it reduces tensile intrados macro strains and therefore reduces the likelihood of loosening masonry under cyclic live loads.

Direct instrumentation of cracks and intrados macro strain measurements have demonstrated that the Archtec anchors positioned across transverse cracks reduce cyclic opening and closing under repeated live loads. The main benefit of this behaviour would be the reduction in load cycles derived hysteretic damage; i.e. opening and closing of cracks under traversing traffic. Reducing this type of damage will almost certainly be beneficial to the bridge service life.

Predictions of strain and displacement made with DE numerical simulations agree well with measured values, both masonry and anchors. Results are conservative because of skew behaviour, transverse load distribution and spandrel wall stiffening.
It has been demonstrated that Archtec strengthening can be designed not only for the ultimate limit state (4) (strength) but also for the serviceability limit state (deflections, strains and stress ranges).

This method of analysing and repairing bridges has been impartially documented by The Construction Industry Research and Information Association CIRA in their document No 656 titled Masonry Bridge Condition, Appraisal and Remedial. The Archtec method of analysis is on page 106 and the Archtec method of repair on page 297.

The methods of assessment and repair using Archtec are also suitable for assessing seismic loadings. It is currently being used on the upgrading of eleven Railway Bridges on the Diakopto to Kalavryta line south of Athens. This rack and pinion railway runs from Diakopto at sea level to Kalavryta, a ski resort passing through twenty-two kilometres of mountains of outstanding natural beauty and is a national monument. The work is to strengthen the arches, piers and abutments before new bearings and track repairs are undertaken.

Cintec India and the Archtec partnership have been running a “health” monitoring programme with the Indian Railways. This programme is to monitor and report on the results of a 1,000 tonne train carrying stone over a number of railway bridges. The monitoring is programmed to take place for one year from March 2007 with quarterly reports on the bridges movement being recorded. In addition, Cintec has been heavily engaged in pricing and evaluating a number of bridge strengthening projects.

A sub-division of Archtec is parapet wall strengthening. This is typified with the work at Magdalan Bridge, Oxford. This historic Bridge over the Cherwell River is used annually to celebrate May Day when the residence and students of Oxford gather in large numbers on the bridge. In 1998, the parapets were tested and found to be inadequate for the loads imposed by the large crowds. This test indicated that parts of the parapet could not withstand more than 2.0kn/m which was less than half that required.

It was obvious that the parapet would cause a problem during these periods of heavy usage. Cintec was specified to carry out a trial strengthening a 6-metre length of parapet on the South West side of the bridge. The test included the positioning of Cintec 2M x M20 anchors vertically through die blocks and 4.5M x M25 anchors horizontally through the pilasters’. In addition, M16 anchors were installed horizontally in lengths between 7 and 10 metres. The test was in February 2002 to comply with the “The Home Office Guide to Safety of Sports Grounds Fourth Edition” and is used specifically for barrier load test rigs. The client assessed that they would need a load level of 5 Kn/m prior to the test.

The test proved that the installed Cintec anchors were more than able to carry the clients’ load and the main contract was completed.


Cintec International has also supplied Network Rail and formerly British Rail and many County Councils and Local Authorities with anchors and reinforcement for the last twenty-two years either directly or through Cintec’s approved contractor network. Cintec and its partner companies are able to offer a complete diagnostic service on all masonry and stone bridges and structures, from initial assessment and a finite element design process through to anchor installation and completion.