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Marshall Field Monumentation Testing

A single concrete (12 inch tube) pillar and a triangular concrete pillar with three marks/mounts were constructed for the test facility. The triangular pillar consists of three 12 inch tubular pillars joined together at the top with concrete and rebar. The triangular section extends one meter below ground and is anchored in the consolidated soil/clay, with roughly two inches protruding above ground. The top of the triangular concrete pillar was then covered with pea-gravel for water drainage and multipath mitigation.

The triangular pillar design was chosen to investigate effects of equipment changes (antennas, antenna height, the addition and removal of radomes etc.) in a controlled, uniform, and fixed triangular system. The design can be installed at field sites with few modifications. The three marks were installed as a true triangle using a stainless steel jig to ensure proper alignment during the pouring of the concrete. SCIGN mounts are used on each of the three schedule 40, stainless steel pipes (located at each corner). There is also a steel pin located in the geometric middle of the triangular pillar with a 5/8" thread at the top for easy installation of most GNSS antennas. The diagrams and photos below show the installation of these monuments. The single concrete tubular pillar was installed about 60 meters to the north, north-west, and will be used to investigate monument stability and data quality of such constructions in consolidated soil.

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diagram of pillar MFP0 diagram of tri-pillar monument top view of tri-pillar and of jig used drill rig starting holes for tri-pillar
drill rig preparing to start holes tri-pillar monument with 3 holes dug back hoe was used to clear top four feet of dirt from tri-pillar tri-pillar with jig in place awaiting concrete
rebar reinforcement in tri-pillar looking down one of holes, jig seen on top tri-pillar waiting for concrete tri-pillar after concrete was poured
wire and rebar support for lone pillar MFP0 MFP0 after concrete was poured tri-pillar covered with pea gravel overall site photo showing MFP0, P041, and tri-pillar in background

Last modified: Sunday, 11-May-2014 17:56:53 UTC

 

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