An arena being built for the Philadelphia Flyers’ minor league affiliate hockey team will be founded on micropiles to mitigate possible sinkhole problems in the limestone bedrock. The arena in located at the site of a catastrophic collapse of a building, Corporate Plaza, in 1994. The collapse was blamed on sinkholes under the foundation that caused settlement and the rupture of a water main, flooding the area and exacerbating the issue. The building eventually had to be demolished. [Source: Morning Call via AGC SmartBrief. Image: CHUCK ZOVKO, The Morning Call]
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Maitland Sinkhole Stabilization Project – Central Florida
A massive sinkhole more than 300-ft in diameter and with depths to bedrock of up to 350-ft is located under a future I-4 traffic interchange in an Orlando suburb. A massive $9 million stabilization project is underway to prepare the site for the eventual TI construction. The size of the Maitland Sinkhole is on par with the largest sinkholes to form in central Florida in recent times. There is not a void present, instead it is infilled with a compressible sand deposit. (Image from FDOT)
The mitigation method includes drilling over 300 grout injection holes, and performing grouting operations to infill cracks in the limestone bedrock. Then in the same holes, compaction grouting will be used as a method of ground improvement to densify the sand in place. Once the grouting is complete, the site will be surcharged to compress any remaining weak layers. Click through for a subsurface profile and location map. Via ASCE SmartBrief.
Historic Pennsylvania Tunnel Reopens with Help From NCFI’s TerraThane Polyurethane Foam
MOUNT AIRY, NC—A $2 million tunnel construction project on the Great Alleghany Passage (GAP) is reopened to the public with help from a geotechnical polyurethane foam called TerraThane, by US company, NCFI Polyurethanes.
The GAP rail-trail is 150 miles of hiking and biking between Cumberland, Md, and Pittsburgh, Pa. created along the former railway line. In Cumberland, the GAP joins the C&O Canal Towpath, creating a continuous 335-mile long trail experience all the way to Washington, DC. It’s become a favorite biking destination for people from around the Mid-Atlantic states. One of its main tunnels, the Pinkerton Tunnel, an 849-foot former Western Maryland Railway tunnel, has been closed since 1975 due to erosion and unstable conditions. The Allegheny Trail Alliance, the organization that built and now maintains the 150-mile GAP, and the Somerset County Rails-to-Trails Association (SCRTA), wanted the tunnel reopened and helped fund the project.
[Editor] Click through for the rest of the press release from GeoPrac sponsor, NCFI Polyurethanes (makers of TerraThane). [/Editor]
Innovative Foundation System for London Office Building
This has to be one of the most complex geotechnical engineering problems I’ve heard of for a building, if not for any kind of project. For starters, beneath the proposed 10-story office building referred to as Cannon Place lies the Cannon Street Train Station built in 1868. Also beneath the site are walls and foundations of a Roman Governor’s palace. In order to accommodate these features, the building has 21-m cantilevers at each end, with the load bearing happening over two groupings of columns at the 1/3 points. In section it looks quite like a 3-span bridge…without the abutments and stacked 10-stories tall! More after the break. (Images by New Civil Engineer) […]