Abstract:
Pipe pile cell foundations are made of interlocked pipe piles that enclose foundation elements such as footings and group pile foundations. They can be temporary or permanent structures with a relatively large section modulus and bearing capacity for the size of their footprints.  The shapes of these foundations can be circular, rectangular, semi-oval, and with or without internal diaphragms depending on the project conditions. Also, they can be built in deep water and/or soft ground with high aseismic performance. This foundation type has been frequently used in Japan for marine foundations of new bridges as well as for the repair and upgrade of existing foundations. Because the piles are interlocked with each other and the cell structures have to be closed, the piles have to be installed very accurately. The case study project in Bangladesh adopted these types of foundations in rivers with widely fluctuating water levels and frequent flooding. The project was to construct three new main highway bridges next to the existing ones that were crossing major rivers while simultaneously repairing existing bridge foundations. Most of the new bridge foundations were placed just next to those of the existing bridges to take advantage of the common pipe pile cells for both new construction as well as the repair of the existing pile foundations. This foundation type was selected for enhancing their aseismic ability and lowering the maintenance requirement against scouring due to seasonal flooding. Press-in piling with water jetting was utilized because of the method’s low vibration feature in addition to the ability to accurately install piles even within a low overhead clearance under the existing bridges. Approximately 460 pipe piles of up to 56 meters (184 ft)-long and 1,000 mm (39.4 in) in diameter were pressed-in from above water.   Â