Inordinate structural failure in several buildings on the Chadron State College campus has occurred in recent years. Disregard for hydrogeologic conditions and their effect on foundation material accounts for part of the damage

Agenbroad, Larry D.

English

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University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Transactions of the Nebraska Academy of Sciences and Affiliated Societies Nebraska Academy of Sciences 1979 Hydrogeologic Relationships to Structural Failure Chadron State College, Nebraska Larry D. Agenbroad Northern Arizona University Follow this and additional works at: https://digitalcommons.unl.edu/tnas  Part of the Life Sciences Commons Agenbroad, Larry D., "Hydrogeologic Relationships to Structural Failure Chadron State College, Nebraska" (1979). Transactions of the Nebraska Academy of Sciences and Affiliated Societies. 301. https://digitalcommons.unl.edu/tnas/301 This Article is brought to you for free and open access by the Nebraska Academy of Sciences at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Transactions of the Nebraska Academy of Sciences and Affiliated Societies by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Transactions of the Nebraska Academy of Sciences- Volume VII,1979 OTHER WATER-RELATED SUBJECTS HYDROGEOLOGIC RELATIONSHIPS TO STRUCTURAL FAILURE CHADRON STATE COLLEGE, NEBRASKA LARRY D. AGENBROAD Department of Geology Northern Arizona University Flagstaff, Arizona 86011 Inordinate structural failure in several buildings on the Chadron State College campus has occurred in recent years. Disregard for hydro-geologic conditions and their effect on foundation material accounts for part of the damage. t t t THE PROBLEM Chadron State College experienced a period of campus growth during the 1960's. Several major buildings were added in those years and in the early 1970's. During the period 1964-71, structural conditions indicative of movement or settlement were noted in several of the new buildings. In particular, the National Guard Armory, the Armstrong Physi-cal Education Building (gym), and the Kline Campus Center (Student Union) were showing stress and failure. The year in which major damage occurred-or at least it had proceeded to the point that repairs were required in these facilities-was 1970. On December 14, 1970, Kirkham & Michael Architects and Engineers made observations of the structural conditions, summarized as: National Guard Armory . .. "extensive settlement has occurred to the extent that exterior walls have cracked clear through and evidently a settlement or tipping action of those walls is occurring. Some bricks have fallen off the exterior faces and some separations in the cracks are up to as much as 2 to 3 inches." Kline Campus Center . .. "extensive settlement has occurred to the extent that wall cracks similar to that observed on the Armory Building has occurred. It was noted that in the mechanical equipment room or the lower level in the southwest corner of this building settlement has cracked the foundation wall. The first floor level has settled to the extent that plaster wall closure surrounding the mechanical room has bowed considerably . . . hollow metal frames for glass walls on the west side of the lower level cafeteria have been crushed to the extent that a normal 2-inch frame is only about 1 to 172 inches thick. It was surprising that the glass had not shattered." Armstrong Physical Education Building . . . "the second column from the west on the south side of the high bay area of the gym has some distress located at the balcony level. The column has a diagonal crack starting at one corner at floor level and proceeding upward to the opposite corner, then around the corner proceeding back down to the floor level. This small portion of the face of the column has separated by approximately 72 inch from the column itself and appears as though it may be caused by a tipping action of the column. On this same column line only at the north side of the gym area, there is observed similar action only at floor level rather than at balcony level. Some overhead framework for gymnastic equipment above the balcony level has pulled loose from the long concrete beam supporting the barrel vault arch roof. A flanged connection supporting one side of this framework has pulled loose from this concrete beam approximately 2 inches to 3 inches." REMEDIAL ACTION National Guard Armory: In 1972, approximately $25,000 in repairs were made to the drainage and air circulation (sub-floor) system in the north portion of the Armory. During 25 26 1975-76, $60,000 was exp~n~ed for the rebuilding of the th wail of the Armory buildmg. nor Kline Campus Center: In 1971, $15,000 was expended for underpinning ~e south,,:est corner of the build~g b~ diving a 36-inch-dlameter Caisson 80 feet deep and filling It \h reinforced concrete. An additional $19,000 was ex-~nded in 1972 for cosmetic repair and restoration. In 1973, ~12,000 was needed to restore air conditioner damage caused by building settlement. Armstrong Physical Education Building: In 1974, $136,500 was spent for steel bands tying the east and west walls to-gether, the replacement of the roof (which had been damaged by shifting), relevelling and relaying the gym floor, and cos-metic repair. In spite of the remedial repair, failure continued with 1975 reports by the building manager indicating ... "joints buckling, plaster cracking, and floor lowering" in the northern part of the southern half of the Kline Campus Center. In the same year, the Armstrong Physical Education Building was experiencing continued roofleakage and floor shrinkage. CAUSE OF THE PROBLEMS Evidence that hydrogeologic factors played a role in the structural failure was indicated during the excavation and installation of the 36-inch-diameter caisson under the south-west quadrant of the Campus Center in 1971. As the caisson was sunk, water had to be removed at an estimated rate of 200 gallons per minute, in order to proceed with the excava-tion. The large yield of water prompted this preliminary analysis of the campus geomorphology and geohydrology. An air photo (Fig. 1) taken in 1920 by Dr. G. E. Condra, State Geologist, shows the confluence of two washes at or near the location of the Armstrong Physical Education Build-ing. A vertical air photo (Fig. 2), taken about 1965, shows that these washes had been filled by simple (noncompacted) procedures and that the football stadium and practice field, the college library, and the north half of the Campus Center were under construction. The Physical Education Building and the National Guard Armory had been completed before 1965. Projection of the wash alignments into the fill areas in-dicates the location of the gym is on the west wash alignment at or close to the juncture with the east wash. Similar analysis suggests the Armory is on the east wash alignment. The southwest part of the Campus Center extends onto the fill of the wash alignment, down gradient from the juncture of the east and west wash. The high yield of ground water from the caisson excava-tion indicated ground water movement through the more permeable fill of the old wash alignments. Although surficial evidence of the washes was obliterated, their position could be reconstructed from the air photos. This was projected further, by plotting the position of shallow, domestic wells in the city, and connecting their alignment with the unmodified remnants of the washes, on the hill south of the campus. Topographic expression, although modified by housing development, helped to locate the former drainage pattern. A plot of the domestic wells in the city is shown in Figure 3. Most of the well locations are coincident with the approximate alignments of the pre-construction (urban) drainage features. The data from Condra's photo allow con-nection of the unmodified portions of the washes, south of the campus, with the well concentrations and topographic lows, defming the original drainage pattern, and is coincident with the damaged structures. It should also be noted that successful wells are in topo-graphic lows along the postulated pre-construction drainage pattern. The low porosity and permeability of the sandy silts of the Chadron Formation and the Tertiary White River Group of sediment are not generally conducive to successful wells. The alluvium along the drainage pattern established by the pre-construction washes would be of much better hydro-logic character, allowing flow of ground water and successful well drilling. In order to present a well-kept and well-landscaped ap-pearance, campus playing fields and lawns are irrigated by sprinklers from apprOximately mid-April until mid-September. Water that is not evaporated or transpired readily inflltrates the permeable fill in former washes, and migrates beneath the damaged buildings. The irrigation water joins water that is derived from natural runoff that still seeks the former drain-age courses where it is not blocked by dams or <;liverted by streets and storm sewers. If the proposed Activity Center (field house) is attached to the Armstrong Building, it is likely to be subject to similar structural failure. SOLUTION The available evidence indicates that the unconsolidated fill material in the former washes contains, stores, and trans-mits a considerable volume of water. Since buildings erected on the old fill exhibit structural failure, I would like to suggest the following: 1. Dewater the fill material in the vicinity of the damaged building by pumping from a series of shallow, low-cost wells. The water removed could be used to irrigate campus lawns and thereby save potable water for hu-man consumption. Dewatering would reduce the in-stability of the foundation material for the damaged 27 buildings and should be done before repair of those buildings is undertaken. 2. Make extensive studies of foundation materials and have design awareness to prevent future buildings from being built on, or near, the former wash alignmen ts. 3. If the proposed tleld house is to be attached to ~ Armstrong Building, the only feasible location south of the current structure. No portion of ~ structure should extend over the previous wash alig ment. Figure 2. Vertical air photo (ca. 1965) of the Chadron State College Campus. Washes have been obliterated. The Armstrong Physi· cal Education Building, the south half of the Kline Campus Center, and the National Guard Armory had been completed. The library and north half of the Kline Campus Center were under construction. (Photo courtesy of Linda Rector.) 28 .==. - .-Figure 3. A map of the city of Chadron showing the location of known shallow wells. Projected topographic alignments of former drainage patterns are coincident with the well locations. Dashed lines indicate a lesser degree of certainty of position. (Photo courtesy of Linda Rector.) 29 

Hydrogeologic Relationships to Structural Failure Chadron State College, Nebraska

UNL | Libraries

University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
Transactions of the Nebraska Academy of 
Sciences and Affiliated Societies Nebraska Academy of Sciences 
1979 
Hydrogeologic Relationships to Structural Failure Chadron State 
College, Nebraska 
Larry D. Agenbroad 
Northern Arizona University 
Follow this and additional works at: https://digitalcommons.unl.edu/tnas 
 Part of the Life Sciences Commons 
Agenbroad, Larry D., "Hydrogeologic Relationships to Structural Failure Chadron State College, Nebraska" 
(1979). Transactions of the Nebraska Academy of Sciences and Affiliated Societies. 301. 
https://digitalcommons.unl.edu/tnas/301 
This Article is brought to you for free and open access by the Nebraska Academy of Sciences at 
DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Transactions of the 
Nebraska Academy of Sciences and Affiliated Societies by an authorized administrator of 
DigitalCommons@University of Nebraska - Lincoln. 
Transactions of the Nebraska Academy of Sciences- Volume VII,1979 
OTHER WATER-RELATED SUBJECTS 
HYDROGEOLOGIC RELATIONSHIPS TO STRUCTURAL FAILURE 
CHADRON STATE COLLEGE, NEBRASKA 
LARRY D. AGENBROAD 
Department of Geology 
Northern Arizona University 
Flagstaff, Arizona 86011 
Inordinate structural failure in several buildings on the Chadron 
State College campus has occurred in recent years. Disregard for hydro-
geologic conditions and their effect on foundation material accounts 
for part of the damage. 
t t t 
THE PROBLEM 
Chadron State College experienced a period of campus 
growth during the 1960's. Several major buildings were added 
in those years and in the early 1970's. During the period 
1964-71, structural conditions indicative of movement or 
settlement were noted in several of the new buildings. In 
particular, the National Guard Armory, the Armstrong Physi-
cal Education Building (gym), and the Kline Campus Center 
(Student Union) were showing stress and failure. The year in 
which major damage occurred-or at least it had proceeded to 
the point that repairs were required in these facilities-was 
1970. 
On December 14, 1970, Kirkham & Michael Architects 
and Engineers made observations of the structural conditions, 
summarized as: 
National Guard Armory . .. "extensive settlement has 
occurred to the extent that exterior walls have cracked 
clear through and evidently a settlement or tipping action 
of those walls is occurring. Some bricks have fallen off 
the exterior faces and some separations in the cracks are 
up to as much as 2 to 3 inches." 
Kline Campus Center . .. "extensive settlement has 
occurred to the extent that wall cracks similar to that 
observed on the Armory Building has occurred. It was 
noted that in the mechanical equipment room or the 
lower level in the southwest corner of this building 
settlement has cracked the foundation wall. The first 
floor level has settled to the extent that plaster wall 
closure surrounding the mechanical room has bowed 
considerably . . . hollow metal frames for glass walls on 
the west side of the lower level cafeteria have been 
crushed to the extent that a normal 2-inch frame is only 
about 1 to 172 inches thick. It was surprising that the glass 
had not shattered." 
Armstrong Physical Education Building . . . "the 
second column from the west on the south side of the 
high bay area of the gym has some distress located at the 
balcony level. The column has a diagonal crack starting 
at one corner at floor level and proceeding upward to 
the opposite corner, then around the corner proceeding 
back down to the floor level. This small portion of the 
face of the column has separated by approximately 
72 inch from the column itself and appears as though it 
may be caused by a tipping action of the column. On this 
same column line only at the north side of the gym area, 
there is observed similar action only at floor level rather 
than at balcony level. Some overhead framework for 
gymnastic equipment above the balcony level has pulled 
loose from the long concrete beam supporting the barrel 
vault arch roof. A flanged connection supporting one side 
of this framework has pulled loose from this concrete 
beam approximately 2 inches to 3 inches." 
REMEDIAL ACTION 
National Guard Armory: In 1972, approximately $25,000 
in repairs were made to the drainage and air circulation (sub-
floor) system in the north portion of the Armory. During 
25 
26 
1975-76, $60,000 was exp~n~ed for the rebuilding of the 
th wail of the Armory buildmg. nor 
Kline Campus Center: In 1971, $15,000 was expended 
for underpinning ~e south,,:est corner of the build~g b~ 
diving a 36-inch-dlameter Caisson 80 feet deep and filling It 
\h reinforced concrete. An additional $19,000 was ex-~nded in 1972 for cosmetic repair and restoration. In 1973, ~12,000 was needed to restore air conditioner damage caused 
by building settlement. 
Armstrong Physical Education Building: In 1974, $136,500 
was spent for steel bands tying the east and west walls to-
gether, the replacement of the roof (which had been damaged 
by shifting), relevelling and relaying the gym floor, and cos-
metic repair. 
In spite of the remedial repair, failure continued with 
1975 reports by the building manager indicating ... "joints 
buckling, plaster cracking, and floor lowering" in the northern 
part of the southern half of the Kline Campus Center. In the 
same year, the Armstrong Physical Education Building was 
experiencing continued roofleakage and floor shrinkage. 
CAUSE OF THE PROBLEMS 
Evidence that hydrogeologic factors played a role in the 
structural failure was indicated during the excavation and 
installation of the 36-inch-diameter caisson under the south-
west quadrant of the Campus Center in 1971. As the caisson 
was sunk, water had to be removed at an estimated rate of 
200 gallons per minute, in order to proceed with the excava-
tion. The large yield of water prompted this preliminary 
analysis of the campus geomorphology and geohydrology. 
An air photo (Fig. 1) taken in 1920 by Dr. G. E. Condra, 
State Geologist, shows the confluence of two washes at or 
near the location of the Armstrong Physical Education Build-
ing. A vertical air photo (Fig. 2), taken about 1965, shows 
that these washes had been filled by simple (noncompacted) 
procedures and that the football stadium and practice field, 
the college library, and the north half of the Campus Center 
were under construction. The Physical Education Building 
and the National Guard Armory had been completed before 
1965. 
Projection of the wash alignments into the fill areas in-
dicates the location of the gym is on the west wash alignment 
at or close to the juncture with the east wash. Similar analysis 
suggests the Armory is on the east wash alignment. The 
southwest part of the Campus Center extends onto the fill of 
the wash alignment, down gradient from the juncture of the 
east and west wash. 
The high yield of ground water from the caisson excava-
tion indicated ground water movement through the more 
permeable fill of the old wash alignments. Although surficial 
evidence of the washes was obliterated, their position could be 
reconstructed from the air photos. This was projected further, 
by plotting the position of shallow, domestic wells in the city, 
and connecting their alignment with the unmodified remnants 
of the washes, on the hill south of the campus. Topographic 
expression, although modified by housing development, 
helped to locate the former drainage pattern. 
A plot of the domestic wells in the city is shown in 
Figure 3. Most of the well locations are coincident with the 
approximate alignments of the pre-construction (urban) 
drainage features. The data from Condra's photo allow con-
nection of the unmodified portions of the washes, south of the 
campus, with the well concentrations and topographic lows, 
defming the original drainage pattern, and is coincident with 
the damaged structures. 
It should also be noted that successful wells are in topo-
graphic lows along the postulated pre-construction drainage 
pattern. The low porosity and permeability of the sandy silts 
of the Chadron Formation and the Tertiary White River 
Group of sediment are not generally conducive to successful 
wells. The alluvium along the drainage pattern established by 
the pre-construction washes would be of much better hydro-
logic character, allowing flow of ground water and successful 
well drilling. 
In order to present a well-kept and well-landscaped ap-
pearance, campus playing fields and lawns are irrigated by 
sprinklers from apprOximately mid-April until mid-September. 
Water that is not evaporated or transpired readily inflltrates 
the permeable fill in former washes, and migrates beneath the 
damaged buildings. The irrigation water joins water that is 
derived from natural runoff that still seeks the former drain-
age courses where it is not blocked by dams or <;liverted by 
streets and storm sewers. 
If the proposed Activity Center (field house) is attached 
to the Armstrong Building, it is likely to be subject to similar 
structural failure. 
SOLUTION 
The available evidence indicates that the unconsolidated 
fill material in the former washes contains, stores, and trans-
mits a considerable volume of water. Since buildings erected 
on the old fill exhibit structural failure, I would like to suggest 
the following: 
1. Dewater the fill material in the vicinity of the damaged 
building by pumping from a series of shallow, low-
cost wells. The water removed could be used to irrigate 
campus lawns and thereby save potable water for hu-
man consumption. Dewatering would reduce the in-
stability of the foundation material for the damaged 
27 
buildings and should be done before repair of those 
buildings is undertaken. 
2. Make extensive studies of foundation materials and 
have design awareness to prevent future buildings from 
being built on, or near, the former wash alignmen ts. 
3. If the proposed tleld house is to be attached to ~ 
Armstrong Building, the only feasible location 
south of the current structure. No portion of ~ 
structure should extend over the previous wash alig 
ment. 
Figure 2. Vertical air photo (ca. 1965) of the Chadron State College Campus. Washes have been obliterated. The Armstrong Physi· 
cal Education Building, the south half of the Kline Campus Center, and the National Guard Armory had been completed. The 
library and north half of the Kline Campus Center were under construction. (Photo courtesy of Linda Rector.) 
28 
.==. 
- .-
Figure 3. A map of the city of Chadron showing the location of known shallow wells. Projected topographic alignments of former 
drainage patterns are coincident with the well locations. Dashed lines indicate a lesser degree of certainty of position. (Photo 
courtesy of Linda Rector.) 
29 


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