A Working Group was set up by the County Surveyors' Society (CSS) and Transport Research Laboratory (TRL) Working Party on Highway Research. The objective was to propose the means to improve the consistency of performance and value for money of expansion joints, reducing the incidence of premature failure and leakage. Each aspect of joint selection, performance and maintenance was studied and a whole life cost study was carried out to weigh the benefits of high initial cost/long-life joints against low purchase cost/short-life options. A Practical Guide has been produced to accompany this report. It was found that most joint failures are caused by traffic loading, faulty installation, poor detailing, or movements much less than the maximum expected - very few are due to the design movement capacity of the joint being exceeded. There are wide variations in the performance of joints, particularly with regard to durability. This appears to be a consequence of the methods use to select, purchase and install joints. At all stages, the pressure is for the joint Supplier to achieve the lowest supply cost and the shortest installation time. There is insufficient incentive to produce a durable joint. There is general agreement that the number of joints on a bridge should be kept to a minimum. Where joints have to be used, sub-surface joints are preferred. The total cost of an expansion joint is very much greater than the supply and installation cost. On busy roads, traffic management and delay costs for joint repair or replacement are such that the cost of the joint is almost irrelevant. It is always worth paying extra for increased service life. (A)
Samenvatting