Using a new bearing production technology, scalable, six inch seismic isolation bearings were built to accurately represent many characteristics of full-scale 24 to 36 inch bearings, including elastomer properties, bearing shape factor, metal layer stiffness and total elastomer height-to-width ratios. Test methods for quarter-scale bearings and components are reported that provide reliability and ultimate strength data. Because reduced-scale tests cost less, larger numbers of relevant tests can be conducted in the development stages of bearing design, thereby reducing overall development costs and increasing reliability.

This four-year project was carried out in an aim to conduct a mid- to long-term, large-scale study on selected field-moulded sealants in concrete joints at different hydraulic structures under extremely cold climatic conditions. Other objectives were to specify installation techniques, carry out periodic inspections, evaluate the performance of various types of such sealants that could be of value to all potential users. The project also included a cost effectiveness study. General and specific guidelines were prepared for sealant selection and their installation. Based on these guidelines, different types of sealants, polyurethanes, polysulphides, silicone (1- and 2-component), were selected for the study. They were installed in horizontal, vertical and inclined joints at different locations on five Hydro-Quebec dams, mostly on the crest, and were periodically inspected for their performance. The findings are presented in this paper.

The aim of the study was to understand the behaviour of bituminous joint sealants during installation using Infra-red thermography in combination with supplemental studies using Dynamic Shear Rheometer (DSR) and High Performance-Gel Permeation Chromatography (HP-GPC). Using IR thermography, in-situ temperature measurement of a joint sealant product was carried out. To evaluate the change in the rheological properties of the product after the installation, due to aging, DSR testing was made for both a fresh and an installed sample. Chemical analysis using HP-GPC was also carried out to see the difference in the state of the polymer used as modifier in the product. The results ensured the suitability of IR thermography for non-destructive quality control during installation of bituminous joint sealants. Overheating of polymer-modified bituminous binders during the installation must be avoided to prevent thermal aging of the polymer. In case the deterioration of the polymer takes place, the binder will act less viscoelastic in practice. Physical and chemical changes in bituminous joint sealants, which have taken place during the installation due to aging, can be well understood by combining IR thermography with the laboratory tests, such as DSR testing and HP-GPC.

Elastomeric bridge bearings were used for the first time in Poland in 1963. They were installed in 16 m span concrete road bridge near Warsaw. The bearings consisted of two layers of neoprene bonded to three steel laminates. After over 30-years service, because of apparent signs of corrosion on exposed steel elements non covered by elastomer, the bearings had been removed and replaced by new ones with steel plates completely encased in elastomer. Eight removed bearings were subjected to the routine compression and shear tests. Despite of fears, their mechanical and physical characteristics have appeared rather satisfactory. Elastomer has maintained good bond to laminating steel plates and the bearings suitable elastic properties. The elastic and shear moduli: E = 392 MPa and G = 1,0 MPa obtained from the tests correspond to the values required in present standards. The bearings did not show any excessive creep under compression and shear stresses. The shape of elastomer elastic hysteresis were comparable to current manufactured bearings. Nevertheless, the material tests of samples cut out of the bearings have shown that the neoprene has lost some of its original properties but not more than 10-20 %. Its hardness did not change very much maintaining the value of 60° Shore A. Tests have confirmed recent hypothesis on a greater durability of elastomeric bearings than predicted a short time ago. Fulfilling appropriate technological requirements these bearings can even reach more than 50-years safe life.

The paper reports about the progress of the European Standards on Structural Bearings, currently under preparation by the technical committee CEN TC 167 under the co-ordination of the author with the collaboration of experts from all EEC and EFTA nations. The objective is the standardisation of all kinds of structural bearings utilised in structures of civil engineering. The standard includes recommendations for the design, specifications for materials, manufacture and installation, criteria for testing and maintenance. Last but not least the standard gives very strict requirements for the conformity evaluation and for the qualification of the manufacturer. The standard is today entirely drafted and nearly entirely approved by the commission. However the necessary procedures for the official translation into the three official languages and the formal vote from all nations participating to CEN will require another 2 years until the standard will became in force. When it will become official the European standard will undoubtedly be a world-wide point of reference for structural bearings and antiseismic devices.