Groundwork CPD: Accelerate reparation time for settlement defects

Overview

In highway development, lightweight fill can be applied to repair settlement defects to increase levelling and to improve overall stability of a road structure.

When widening an existing carriageway, the weight of the newly constructed fills can often result in the new surface settling lower than the original surface and could pull the existing surface out of level. With the help of lightweight fill embankments that require widening can be constructed with minimal increased loading to the existing structure.

With respect to the project special features, lightweight expanded clay aggregate layer can be designed to fulfil several objectives at one time: to provide frost insulation, to block capillary water rise and to function as a drainage layer.

During this CPD webinar, we will highlight a case study on the N18 Bunratty Bypass in County Clare in Ireland, which was originally constructed in 1990 over soft subsoils which were thought to be where the local river used to flow. The westbound section of the dual carriageway had settled substantially over five areas along the stretch adjacent to Bunratty Castle. This required urgent replacement with a solution which would reduce the settlement issues and not pose any groundwork issues in the corresponding area.

The event is sponsored by Leca, who are kindly making a donation to the ICE Benevolent Fund.