Hastings bridge: Explosions will test pile strength
Businesses and residents near the Hastings Bridge may hear several "claps" of noise from the construction site as a result of the use of small explosives to assess pile strength capacity. The first clap could be heard late this week, if all goes as planned.
Explosives are used for "statnamic load testing" on test piles that have been driven into the ground successfully. In total, there will be no more than six of these explosions over approximately two weeks, and the tests should be limited to daylight hours, according to recent bridge work updates. Statnamic load testing began Nov. 29 and should be completed by Friday, Dec. 10.
Load testing is the final aspect of the pile testing effort for piers six and 10 of the new bridge. Pile testing is one of the ways to verify the bridge will be able to manage the required loads.
Two-way traffic will remain open on the bridge and access to local businesses and residences should not be affected.
On the north bank of the river, crews finished placing the last of the piles for the north approach ground improvement project. With that finished, they will begin focusing on work near and in the river.
One test pile for pier 10 has already been successfully driven to the proper depth. A second test pile for pier six is just about ready to be driven.
As work finishes on the land improvements, crews are preparing for work in and near the water. Stone from local quarries is being placed in the river to create a temporary 55-foot-wide rip-rap causeway that will stretch 400 feet into the river. This will allow crews to work on piers eight, nine and 10 "on" the river. As of Tuesday, there was about a day's worth of work left to be done on the causeway.
Also being installed is a cofferdam for pier 10. A cofferdam creates a dry workspace in the river that will allow crews to eventually pour pier footings. Similar cofferdams will be installed for other piers in the next few weeks.
Activity will begin to pick up next week near the old Hudson building as crews begin staging and preparation for future work in that area.
Motorists and community members who have questions or concerns are encouraged to call the Hastings Bridge Project Hotline at 651-775-5244 or visit the project's web site at www.dot.state.mn.us/hastingsbridge.