Geological Report.pdf
PDF 2 MB Posted
- Solicitation number
- 1240BJ21R0005
- Issued by
-
Department of Agriculture Forest Service
About this file
This document contains a geological report and related federal contract opportunity. The geological report provides details of a site investigation conducted for the reconstruction of the Anan Bear Observatory in Alaska. It describes the site conditions, rock types and mass, rock mass observations including fracture traces and surfaces. It also discusses geologic hazards and provides recommendations.
The related federal contract opportunity is a solicitation to reconstruct remote bear viewing facilities at Anan Creek in Alaska. The base work includes demolition and removal of observation decks and stairs, relocating structures, demolishing a trail, and constructing footings, decks, shelters, trails and signs. Optional work comprises building a temporary staircase, repairing an existing staircase and deck, and preparing drawings for a future spiral staircase. This is a total small business set-aside solicitation issued by the USDA Forest Service, Alaska Region for the Topngass National Forest, Wrangell Ranger District. The closing date is not provided.
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9360 Glacier Hwy., Suite 1 Juneau, Alaska
July 9, 2020 .12
250 Street , Alaska, 99503
Site
. appreciates a A , Alaska. ist isti alysis .
T e- as in
9, 202 neer Mark wski pa platf acent .
li i at tra
Introduction – Site Conditions:
y
; ’s in situ . T is ily surface at - plates. T -f 10- fi tunnel transects el Anan Creek, tra Anan Creek upstr structure.
- is
n. is r fr , Page 2 Anan Bear Observatory Reconstruction July 9, 2020 Geological Site Investigation
- ass is ly uplift ’s surface, release tensile stresses p surface. C nifest in erns wi t Creek. , flat terrain.
Rock Type and Rock Mass:
was s , ite/ te.
sets, e a at Anan Creek e s r
15- s appears ; w , uate retai .
e, cliff face, resultin release surface its release -
Rock Mass Observations:
s . T lists
-site
1. racture
2. racture
3. racture persistence ( l c acture racture aperture, ( surfaces
5. racture type
6. R
8. W
9. W , ’
10. W fractures
11. tence surfaces
Page 3 Anan Bear Observatory Reconstruction fracture traces s-fracture le, a fracture surface a was -cut a separate fracture 3 rees a ne .
s articu fractures s cut . fracture spaci .
r accu s s, can at least
, trace fracture w n separate an apparent a int se -lity issues particularly ep cliffs.
acture surfaces typically ;
s a eat
ts. ears s intact wi , ’s e Alaska
) Alaska Field Rock Classification and Structural Mapping Guide. rial is R5, Very
’s I .
surface planes.
Al ter- -cut earlier- ractures. aces were -swell lenses,
- , typicall ss . was was result , east-west steeply , . A cial ice es ri .
were lat itself
Geologic Hazards:
i fracture s s fracture cliff faces cycles fracture surfaces. ese will caus i r faces.
can ale an .
at site appears t Anan Creek cliff faces w
Page 4 Anan Bear Observatory Reconstruction
- w , Recommendations:
1. crystalline .
2.
In 80 crystalline r psf.
3. n , c e r . s si.
, . 250 psi
, any l n re er ste face, spiral staircas ck s future
5. can fractures w es. ew r pr . s use ne r r
. site ter
6. , it is ert ential u te y , t al int
8. site al ass a ref ese
Page 5 Anan Bear Observatory Reconstruction will nificant c t wit n . wil w
. al/ essential rk f s e . at re -ully t . If nal , please fee
Sincerely, Mark .
Seni er
, al
7-9-2020
Appendix A
APPENDIX A
Vicinity Map, Existing Conditions, Site Profile and Site Section Drawings
SOUTHEAST
ALASKA
ALASKA
LOCATION
MAP
VICINITY MAP
JUNEAU
SOUTHEAST
ALASKA
GRAHAM
ISLAND
CANADA
UNITED STATES
THIS
PROJECT
TOPOGRAPHY FROM:
A
B
60 FT.
SCALE IN FEET
0 30
NORTH
EXISTING CONDITIONS
CREEK
ANAN
OBSERVATION PLATFORM
FISH PASSAGE TUNNEL
BELOW SURFACE
OBSERVATORY
SURFACE
STRUCTURES
GRAVEL
PATHWAY
STREAM BANK
SHOWN
APPROXIMATE
TUNNEL ENTRANCE
TIMBER STAIRWAY
EXPOSED GRANITE
ROCK KNOB
COLLUVIAL GRANITE
BOULDERS ALONG
STREAM BANK, TYP.
PROJECT
LOCATION
TOPOGRAPHY FROM R&M ENGINEERING-KETCHIKAN, INC., 2020
VI
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Appendix B
APPENDIX B
Site Photographs
View looking southwest into Anan Creek Lagoon.
Anan Creek is seen draining into tidewater over exposed and highly fractured, massive granite.
Photo 2:
Complex fracture patterns seen in exposed granite at the mouth of Anan Lagoon.
Photo 3:
Exposed granite seen below a windblown tree root plate alongside Anan Creek.
Photo 4:
TYPICAL
FRACTURE
PLANES EXPOSED
MASSIVE
GRANITE
View of the Observatory boardwalk with an exposed granite cliffside in the background.
Photo 5:
View looking downstream along Anan Creek. The blocky-shaped, granitic boulder deposits seen here are typical for the area.
Photo 6:
Anan Creek cuts through a mass of granitic bedrock at tidewater of Bradfield Canal.
Photo 1:
TYPICAL
FRACTURE
PLANES
EXPOSED
GRANITIC
BEDROCK
Tools of the trade: hammer, pick, brunton compass, headlamp and chest waders.
Photo 10:
View looking into the fish passage tunnel from atop the bear observatory platform.
Photo 9:
FRACTURES
OBSERVED
ON TUNNEL
WALLS AND
BACK
View looking south across Anan Creek from project site at an exposed mass of highly fractured, massive granite.
Photo 7:
View looking east and across Anan Creek from project site at the same exposed, highly fractured mass of granitic bedrock.
Photo 8:
TYPICAL
FRACTURE
PLANES
TYPICAL
FRACTURE
PLANES
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