Deep Drill-Braced Monuments

The deeply anchored drill-braced geodetic monument is perfect for site that require:

non-bedrock sites (e.g., alluvium)
very stable moument requirements

Deeply anchored, drill-braced monuments consists of a vertical, schedule 80, galvanized pipe mounted in non-shrink grout in a 4.5" diameter hole drilled to about 40' deep, laterally stabilized by 4 additional rods welded to the top of the monument, each anchored 40' deep (minimum), 4.5" to 4.75" diameter holes. Each anchor hole will be cased in the upper 12' - 14' with 2.5' diameter, schedule 80 PVC wrapped with 3/4' thick refrigeration foam protected by layers of strapping tape and duct tape. We have a detailed Statement of Work (SOW) for the monument construction. If you are interested in receiving a PDF copy of the SOW, please e-mail charlier@geology.cwu.edu

Materials, Costs and Drawings

Technical drawing
Installation costs

Ancillary Equipment

We used Trimble SSI receivers and choke ring antennas with stainless steel recoverable antenna mounts on our drilled braced monuments. The antenna mount was modifed from a Mark Smith (JPL) and Frank Wyatt (Scripps) design. We are now using the standard SCIGN-type anentta adapter and modifying existings sites for SCIGN-type radomes.

All of our sites have secure and covered facilities. We use NEMA/EEMAC Type I enclosures with bulkhead fittings. The enclosures contains the GPS receiver, U.S. Robotics 56 kbs modem or Freewave radio modem and heavy duty surge protectors. The surge protectors isolate all components from lighting strikes or AC power surges.

Photos

Off loading the drill rig from the trailer at the Goldendale Observatory Site.
Beginning to drill the northern angle hole at Cape Blanco.

Sunset over the drill rig. It took over four days to finish the drilling at Cape Blanco.
The monument is frestly painted; the antenna was just installed at Pacific Beach.

Type I NEMA utility box, with GPS receiver and electronics located in Maintanence Shed Office of Pacific Beach.
Sunset after the successful installation of the monument, Pacific Beach.

Off loading the drill rig from the trailer at the Goldendale Observatory Site.	Beginning to drill the northern angle hole at Cape Blanco.
Sunset over the drill rig. It took over four days to finish the drilling at Cape Blanco.	The monument is frestly painted; the antenna was just installed at Pacific Beach.
Type I NEMA utility box, with GPS receiver and electronics located in Maintanence Shed Office of Pacific Beach.	Sunset after the successful installation of the monument, Pacific Beach.