Strip Seal Expansion Joint Half-Width Construction Method for Busy Highways

The half-width construction method allows strip seal expansion joints to be installed or replaced on busy highways while maintaining traffic flow in both directions. This method is preferred for bridges where full closure is not acceptable due to traffic volume or emergency access requirements. The half-width method divides the joint installation into two phases. In Phase 1, traffic is shifted to one half of the bridge using temporary lane markings and barriers. The joint on the other half is removed, the substrate is prepared, and the new joint is installed. Rapid-strength concrete is cast and cured overnight, allowing traffic to shift to the completed half for Phase 2. Traffic management for the half-width method requires careful planning. The temporary traffic arrangement must provide adequate lane widths for the expected vehicle types, including heavy goods vehicles and emergency vehicles. Temporary barriers must be robust enough to contain errant vehicles. Advance warning signs must be placed at sufficient distance to allow drivers to adjust their speed and position. Substrate preparation for the half-width method must be completed within the available working time. Saw cutting, concrete removal, and surface preparation must be sequenced to allow the new joint to be installed and concrete cast before the end of the working shift. Pre-cutting of the saw lines before the traffic shift begins can save significant time. Concrete curing under traffic is a challenge for the half-width method. The concrete adjacent to the traffic lane is subject to vibration from passing vehicles, which can damage fresh concrete. A minimum distance of 1 meter from the traffic lane to the fresh concrete pour is recommended, with temporary barriers providing additional protection. Quality control for half-width construction must be maintained despite the time pressure. Gap setting, level, and alignment must be verified before concrete is cast. Concrete test cubes must be taken and cured under the same conditions as the in-situ concrete. Traffic should not be permitted on the new concrete until the specified minimum strength is achieved.