HomeMy WebLinkAboutAttachment C - Lindley Center - 2014 Structural AssessmentStructural Assessment Report
Prepared For:
City of Bozeman
Facilities Department
20 E. Olive St.
Bozeman, MT 59771
Lindley Center
Prepared By:
Stahly Engineering & Associates, Inc.
7585 Shedhorn Drive
Bozeman, MT 59718
(406) 522-9526
May 2014
STRUCTURAL ASSESSMENT REPORT
FOR
Lindley Center
PREPARED FOR:
CITY OF BOZEMAN
FACILITIES DEPARTMENT
20 E. OLIVE ST.
BOZEMAN, MT 59771
May 2014
PREPARED BY:
STAHLY ENGINEERING & ASSOCIATES
7585 SHEDHORN DRIVE
BOZEMAN, MT 59718
PHONE: (406) 522-9526
FAX: (406) 522-9528
Written By: Theron Thompson, P.E.
Senior Engineer
Structural Assessment Report 1
I. Summary
The Lindley Center, located at 1102 E. Curtiss Ave., is a City of Bozeman owned
facility that is available to the public to rent for meetings, receptions, etc. The facility
is also used for other Parks and Recreation Department needs including storage.
The purpose of this structural assessment report is to identify and document the
specific functional and structural deficiencies that need to be addressed.
The structure was thoroughly inspected on April 29 through May 1, 2014. The
structure, as well as any identified issues, is documented herein. A preliminary
structural analysis was also completed to identify any deficiencies and is also
included in this report. Required corrective actions and retrofits are summarized
with a general cost estimate for the required corrections.
Figure 1 – Lindley Center
II. Facility/Structure Description
A. Facility Overview
The Lindley center has a main level of approximately 2860 square feet comprised of a
public room, kitchen, restrooms and a single office. The basement is approximately
2000 square feet which is currently being used for storage. The original basement
housed locker rooms and restrooms. The mechanical systems are also located in the
basement.
The original Lindley Center building is a log structure on a stone foundation (See
Figure 2). The facility has had many additions made to the original structure. The
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additions are generally standard wood framing on concrete foundation. There is a
portion of concrete floor at the main level. There is also a portion of the foundation
that was replaced with CMU.
Figure 2 – Original Lindley Center Building
B. Roof Structure
The roof structure is comprised of multiple different framing types. Area 1 (See Figure
4) is comprised of trusses at 24” on-center. The trusses are hand-made of rough sawn
(R.S.) 2x4’s with nailed connections (See Figures 3, 5 &6)
Figure 3 – Area 1 Trusses and Framing Revision
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Figure 4 – Lindley Center Roof Framing
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Figure 5 – Area 1 Trusses
Figure 6 – Area 1 Trusses – Connection to (3) 2x12 Beam
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Area 2 is comprised of 3”-4” diameter logs with a standard sawn 2x6 at 24” on-center.
See Figure 3 and 7 for the framing to the triple 2x12 beam. Area 3 is framed similarly
to Area 2. See Figure 8 for framing of Area 3
Figure 7 – Area 2 – Log and 2x6 Bearing on (3) 2x12 Beam
Figure 8 – Area 3 – Log and 2x6 Beyond
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Area 4 consists of 3”-4” diameter logs spanning between the supporting walls/beams
and a 7”-8” diameter ridge beam, with an 8” log mid-beam (See Figure 9). The ridge
beam spans between the former end walls and timber trusses. The end walls have been
revised to allow for doorways, and to open the end of the building up for the addition to
the South. Multiple courses of 7”-8” diameter logs were left in place to span the new
openings, which can be seen in Figure 9.
Figure 9 – Area 4 – Roof Log Rafters and Log Ridge Beam
Figure 10 – Area 4 – Ridge Beam to Log Truss
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The timber trusses are constructed of 8” diameter log top and bottom chords and 6” diameter
webs (See Figures 9, 10 & 11). The center web is a ¾” diameter steel rod with steel plate
washers (See Figure 12). The trusses are supported on 8” diameter log columns.
Figure 11 – Area 4 – Log Truss Looking From Below
Figure 12 – Area 4 – Log Truss Steel Rod Connection
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Area 5 is constructed with 1”x8” tongue and groove roof boards over 3”-4” diameter
log rafters and is open framing. The beams supporting the framing between Areas 4
and 5 consists of two 8” diameter log beams (See Figure 13).
Figure 13 – Support Beams Between Area 4 and 5
Area 6 is comprised of hand-made trusses with 2x6 top and bottom chords and 2x4
webs (See Figure 14, 15 & 16).
Figure 14 – Area 6 – Trusses
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Figure 15 – Area 6 – Trusses
Figure 16 – Area 6 – Trusses
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C. Floor Structure
The floor structure is comprised of multiple different framing types, but is generally
constructed of rough sawn 2x8 joists at 16” on-center with 8” tongue and groove floor
boards (See Figure 17). Area 1 (See Figure 19) is comprised of a concrete slab (See
Figure 18). The depth and reinforcing could not be determined during the inspection,
but is assumed to be 4” thick with #4 reinforcing bars at 12” on-center.
Figure 17 – Typical 2x8 Floor Framing
Area 2 is comprised of rough sawn 2x6 joists with the same 1x8 tongue and groove
flooring. Area 3 is an in-filled stairs with 2x4 floor joists (See Figure 20).
Figure 18 – Area 1 - Concrete Floor
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Figure 19 – Lindley Center Floor Framing
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Figure 20 – In-filled Stairs Framing
Area 4 is a newer section of floor that is comprised of standard sawn 2x8 joists at 16”
on-center (See Figure 21).
Figure 21 – Area 4 – 2x8 Joists
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The concrete floor in Area 1 is supported by a triple rough sawn 2x8 beam which is
supported by a 6x6 post and a concrete column, as seen in Figures 22 and 23.
Figure 22 – Area 1 – Rough Sawn (3) 2x8 Beam Supporting Concrete Slab
Figure 23 – Area 1 – Beams to Concrete Column
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The concrete column also supports a 6x6 beam which is sandwiched between two
2x12s (See Figure 24). The beam continues to a 6x6 post and on to a 6x6 post in the
interior wall (See Figure 25).
Figure 24 – Beam to Concrete Column
Figure 25 – Beam to 6x6 Post
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In the same room, the other beam line is a 7” diameter log beam supported on a 7”
diameter log post (See Figure 26). The area containing the stone fireplace and footing
is the floor under the kitchen and restroom addition. The footing supports a 7”
diameter log beam from the wall above and a 6x6 beam on each side, which supports
the floor (See Figure 27).
Figure 26 – 7” Diameter Log Post Supporting Log Beam
Portions of the kitchen and restroom floor are also supported from the stone fireplace
(See Figure 28). The Area 2 floor is supported on a 6x6 beams which run parallel to a
7” diameter log beam that carries the load from above (See Figure 29 & 30). These
beams are supported on a 7” diameter log post.
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Figure 27 – Footing Supporting 6x6 Beams and 7” Diameter Log Beam
Figure 28 – Stone Fireplace Supporting Floor
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Figure 29 – 6x6 Beam Supporting Floor
Figure 30 – 7” Diameter Log Beams and 6x6 Beams Supporting Floor
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The room to the left of Area 2/3 contains the mechanical equipment for the building.
The floor in this area is supported by a 6x6 beam which is supported by a 6x6 post at
one end and a 7” diameter log post on the other (See Figures 31 & 32).
The room to the left of the mechanical room supports the floor on two built-up beams
of (3) flat 2x6s. In between the built-up beams is a 7” diameter log which supports the
roof load (See Figure 33). The beams are supported on 7” diameter log posts, the
concrete wall and the stone fireplace.
Figure 31 – 6x6 Beam Supporting Floor
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Figure 32 – 7” Diameter Log Post Supporting 6x6 Beam
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Figure 33 – 7” Diameter Log Beam With Two Triple Flat 2x6 Beams
Figure 34 – Beams Supported by 7” Diameter Log Post
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Area 3 is supported on a double 2x6 beam which is supported on 4x4 posts at each end
(See Figure 20). The floor joists are also supported by the walls in this location. The
floor in Area 4 is fully supported by the concrete walls on all sides. The room to the
left of Area 4 is one of the old locker rooms. The floor in this area is supported by a
W10x15 steel beam on a steel pipe column (See Figure 35 & 36).
Figure 35 – Steel Beam Supported by Pipe Column
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Figure 36 – Steel Beam From Below
D. Foundation
Portions of the original foundation were constructed of stone (See Figures 37 & 38).
Most of the foundation, including the additions, was constructed of concrete basement
walls (See Figures 39 & 40). There is a small portion of the foundation that is
constructed of CMU (See Figure 41).
Indications seem to show that the original stone foundation was strengthened with a
concrete wall poured on the inside face. The original structure was most likely not
constructed on a basement, and the concrete basement walls were probably added later
to create the basement and strengthen the stone foundation.
The CMU portions look like they were added to fix portions of the stone foundation
that were failing. Sections of the stone foundation on the exterior were added as a
façade to match the existing stone foundation.
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Figure 37 – Original Stone Foundation
Figure 38 – Original Stone Foundation
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Figure 39 – Concrete Basement Wall Foundation
Figure 40 – Concrete Basement Wall Foundation
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Figure 41 – CMU Foundation
III. Deficiencies
A. Roof Structure
The roof structure was constructed of log rafters and hand-made trusses. In areas, the
log rafters were strengthened with an additional 2x6 at each log. The roof structural
members were analyzed and are as follows (See Attachment B for calculations):
Roof Member
Max
Demand/Capacity
Ratio
Connections Connection
Adequacy
Area 1 Trusses – See Figure 3 2.74 3 – 16d Nails Deficient
Area 4 Log Trusses – See
Figure 11 0.255 Unknown --
Area 6 Trusses – See Figure 14 1.692 3 – 16d Nails Deficient
4” Log Rafter 1.302 -- --
4” Log Rafter W/ 2x6 0.838 -- --
8” Ridge & Mid Beams 0.731 -- --
(3) 2x12 Beam 7.336 -- --
Any member with a demand–to-capacity ratio greater than one is deficient. The hand-
made trusses were generally nailed at the connections with three 16-penny nails. The
connections require anywhere from 10 to 15 nails per the analysis. The rood diaphragm
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consists of the 1x8 tongue and groove boards. The nailing of the boards could not be
verified, but most likely is adequate for the diaphragm loads.
The roof structure is supported on standard wood framed walls, log walls and columns.
The columns are either 6x6 posts or 7” diameter logs. The capacity of a DF#2, 6x6
post at an 8’ length is 18,905#. This exceeds any required column load in the structure.
B. Floor Structure
The floor structure was generally constructed of rough-sawn 2x8 joists with areas of
standard sawn 2x8 and rough-sawn 2x6 joists. There is also an area of floor
constructed of a structural concrete slab. The beams vary from built-up 2x8 beams, 6x6
beams and log beams. The floor system was analyzed and the members are as follows
(See Attachment B for calculations):
Member
Max
Demand/Capacity
Ratio
2x8 R.S. Joists 0.459
2x8 Standard Sawn Joists 0.522
2x6 R.S. Joists 0.568
#1 - (3) 2x8 R.S. Beam 2.312
Concrete Slab 1.132
#2 - 6x6 W/ (2) 2x12 Beam 1.241
#3 - 8” Diameter Log Beam 0.931
#4 - 6x6 Beam 0.923
#5 - 6x6 Beam 1.584
#6a – (3) 2x6 Flat Beam 0.673
#6b - 7” Diameter Log Beam 0.902
#7a - 6x6 Beam 1.193
#7b - 7” Diameter Log Beam 1.44
#8 – W10x15 Steel Beam 0.511
The floor structure is supported on concrete basement walls and columns. The columns
are either 6x6 posts or 7” diameter logs. The capacity of a DF#2, 6x6 post at an 8’
length is 18,905#. This exceeds any required column load in the structure.
All floor joists connect to the supporting structure with bearing type connections. The
beams connect to all columns with bearing type connections. Throughout the
basement, the beam connections to the columns are deficient and need positive
connections utilizing plates, straps or other connection hardware.
There are also locations where there is not a clear load path. The floor appears to be
supported on beams running parallel to log beams carrying the load from the roof (See
Figures 29, 33 & 34). All three beams are supported on a single column with transfer
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blocking. The blocking is insufficient and does not supply a positive connection to the
column.
The basement columns not located in a wall do not provide a positive connection to the
foundation (See Figures 42 & 43).
Figure 42 – 6x6 Column to Foundation
Figure 43 – 7” Diameter Log Column to Foundation
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C. Foundation
The original foundation, constructed of stone, does show signs of failing in limited
areas (See Figures 44 & 45).
Figure 44 – Stone Foundation
Figure 45 – Stone Foundation
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The remaining concrete and CMU foundation is generally in good condition. There
were no signs of major cracking or settling. There are limited areas of degradation and
water damage to the foundation (See Figure 46).
Figure 46 – Foundation Degradation and Water Damage
D. ASCE 31 and Lateral System
The ASCE 31, Seismic Evaluation of Existing Buildings, Tier 1 assessment and
checklists were completed (See Attachment A for checklists). The facility is classified
as a Life Safety level of performance and a High seismicity level. The following
checklists were completed based on that classification:
Basic Structural
Supplemental Structural
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Geologic Site Hazard and Foundation
Intermediate Nonstructural
Based on the findings of the checklists the following items were found as non-
conforming:
The required shear walls need to be sheathed and nailed to provide code
compliant shear walls.
The cripple wall in the basement (See Figure47) is missing sheathing to transfer
the lateral load to the foundation.
The wood posts in the basement need to have positive connection at the top and
bottom as discussed previously.
Anchor bolts could not be located to attach the sill plate to the foundation (See
Figures 48 & 49).
The required shear walls do not have holdowns to anchor the walls to the
foundation.
The foundation is deteriorated at locations identified previously.
The mechanical equipment, ducting and piping needs to be seismically braced.
Flexible couplings are not installed for fluid and gas piping.
Figure 47 – Cripple Wall
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Figure 48 – Sill Plate to Foundation Wall
Figure 49 – Sill Plate to Foundation Wall
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E. Miscellaneous Issues
There are a few miscellaneous issues to consider, which may or may not directly affect
the structural integrity of the facility. There were limited areas where water damage
was noted (See Figures 49 & 50). This has caused some rot to the wood framing.
Figure 49 – Water Damage in Basement
Figure 50 – Water Damage and Rot
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The area of water damage and rot seem to be in a limited area, but would need to be
verified to a greater extent during remodeling. A larger scale issue is the amount of
damage done by the animals that have made the facility there home (See Figures 29, 51
& 52). In most locations during the inspection, evidence was found of mice, squirrels
and birds living in the basement, walls and roof.
Figure 51 – Birds Living in Exterior Wall
Figure 52 – Birds Living in Exterior Wall
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IV. General Cost Estimate
A basic cost estimate to address the deficiencies noted in the report was
completed (See Figure 53). Further cost analysis should be completed to hone
the cost of addressing the structural deficiencies, and an estimate from a
contractor should be completed.
Figure 53 – Cost Estimate for Structural Deficiencies
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A basic cost analysis, based on square footage, was also completed to address
the remodeling of the facility (See Figure 54). An analysis should be completed
by an architect to determine the needs of the facility and the costs involved with
remodeling the facility.
Figure 54 – Cost Estimate for Remodel and Total Project
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Attachment A
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Attachment B