HomeMy WebLinkAboutRe: geotechnical observations CTL ANDERSON QNGINE-QRINC, P.A.
1625 SOUTH SECOND AVENUE - ANOKA, MINNESOTA 55303
OFFICE&CELL PHONE: 612 518 5317 - FAX:763 422 9615
ENGINEERING FIELD REPORT
Client: Michael Scott Homes, Inc. May 22, 2007
701 Ivanhoe Drive
Watertown, MN 55388
Site: 4725 North Shore Drive
Site Visit: May 8, 2007
Geotechnical Observations:
This home under construction at 4725 North Shore Drive will share a tram lift with the future house at
4731. The topographic survey map you provided shows a total vertical drop from the street to the lake
of 56 feet across a horizontal distance of 212 feet. It is understood that the tram will utilize a 25 by 8
foot cribbed earthen platform presently on the lake side of the houses for the top launching area. This
platform sits about 37 feet above the lake surface. The survey also shows that the lake shore is at a
horizontal distance of about 52 feet from the edge of the platform and that the lake surface elevation is
929.06 feet
Presently there is a wooden stair way consisting of 3 segments of 15 each, 2 by 10 lumber treads, 8
inch risers, separated by 2 landings plus an additional landing at the stair bottom. The landings are 34
inches deep front to rear.
To examine soil conditions along the tram alignment, soil auger probes were made starting at the base
of the cribbed earthen platform and then opposite each of the three landings. The test holes were
made along the approximate alignment of the proposed tram.
Test Elev. 963, Test Elev. 955, Test Elev. 945, Test Elev. 935,
hole 1 3'toward hole 2 13'toward hole 3 26'toward hole 4 39'toward
lake" lake* lake* lake*
0'to 2' Black 0' to 2' Black 0' to BlackBlack
cla topsoil claytopsoil 1.5' claytopsoil 0'to 1' clay topsoil
Tan lean 2' Tan lean 1.5'to Tan lean Tan lean
clay clay 3' clay1 #0 3 da
* measured horizontally from toe of the cribbed earthen platform
The test holes consistently showed black clay topsoil, somewhat organic, underlain by tan colored lean
clay. The tan lean clay appeared to be undisturbed glacial till and was quite stiff. Boulders were not
encountered but are likely, randomly present in the clay.
You indicated that there may have been a history of erosion on the existing bank slope. Evidence of
erosion was seen in the vicinity of test hole 3. The soil around the base of a tree appeared eroded
removing less than a foot—measured normal to the bank slope. Further down the slope opposite test
hole 4, batter boards had been installed in an attempt to hold back the soil. The entire surface of the
bank slope is covered over with a coarse net. Brush, possibly sumac, has grown up through the net.
i
Opinion:
The soil can be expected to provide adequate support for the tram foundation which we understand will
consist of pipes driven into the soil. It would be advisable to construct a concrete base at the bottom of
the tram to help support the thrust load.
I hereby certify that this report was prepared by me and that I am a duly Licensed Professional
Engin er under the laws of the State of Minnesota.
vs.AND
Carl E. Anderson, P. E., P. G. G`2 ~"'••.s';
Registration Number 90736
10736