What makes it interesting?
While river piers were strengthened and a new aesthetic pier facing were completed while the existing bridge was still open to traffic, Kokosing completely replaced the superstructure within an aggressive 300-calendar-day closure window. Kokosing met challenges brought on by heat and other factors using ingenuity and partnering with subcontractors to save the project money and time.
How HCSS Software assisted with this project
HCSS HeavyBid was utilized for all aspects of the project estimate. The use of holding accounts, child items, and non-additive biditems allowed for efficient analysis of multiple demolition and erection scenarios. Additionally, Kokosing continued using Heavybid post-bid to analyze Value Engineering concepts and generate project budgets.
The $24-million Dick Henderson Bridge replacement over the Kanawha River involved many unique features.
Initially, the existing river piers were strengthened with micropiles installed through the existing pier foundations, and a new aesthetic pier facing was poured to the bottom of the pier caps, which were completely replaced. Divers first installed reinforcing dowels in 28 feet of water to allow for underwater tremie seal placement, then sheet piling cofferdams were utilized to allow for dewatered access to the top of footing. This work was completed while the existing bridge was still open to traffic. All main span work was completed using barge-mounted equipment, and concrete was slick-lined from the river banks through underwater tremie pipes.
During an aggressive 300-calendar-day closure window, the superstructure was completely replaced. The existing three-span truss bridge was demolished by lowering multiple main-span panel units simultaneously, while the end spans were explosively demolished. New 11-foot-tall plate girders were erected utilizing pier support frames that allowed the girders to temporarily cantilever up to 160 feet off the piers until the drop-in pieces could be erected. During erection in mid-summer, the drop-in keystone pieces expanded due to heat and would not fit. The erection crew ingeniously dipped the 130-foot-long girders into the river to cool them, which allowed for proper fit-up.
The bridge approaches were initially designed by the owner to contain over 18,000 cubic yards of lightweight foam fill bounded by mechanically stabilized earth (MSE) walls. This solution eliminated settlement concerns as the approaches were being constructed over significantly weak soils and within 5 feet of structures which were to remain. However, the foam fill-in-place of typical MSE granular backfill presented difficulties with maintaining MSE wall panel alignment and added substantial cost to the project. Kokosing partnered with a ground improvement subcontractor to Value Engineer a solution that improved the underlying soils and allowed the construction of conventional MSE walls with granular backfill, thereby eliminating the foam fill. This solution saved the project $480,000 and minimized both short-term risk and future maintenance costs.
This bridge construction project was vital to the local communities of St. Albans and Nitro which are connected across the Kanawha River by the structure. Kokosing Construction completed this project on-time and under budget and earned over $1 million in early completion incentives.