ONTARIO AQUATIC CENTER CITY OF ONTARIO, OREGON
STRUCTURAL INTEGRITY ASSESSMENT
SCOPE
This report conducted on August 1st, 2006 summarizes our structural integrity assessment of the Ontario Aquatic Center. We completed a visual inspection of the block walls and columns, the main and intermediate glu-lam girders and beams, and exterior walls, foundation and roof. An inspection of the
intermediate wood framed bearing and non-bearing walls of the clerestories was performed along with 5 exploratory holes. Two samples were sent to Aeration PAK for mold analysis.
INTRODUCTION
The original facility consisted of an outdoor pool with dressing rooms and restrooms for men and women. In 1983, the facility was upgraded to a new indoor main pool, training pool, and hydro pool in one pool room plus a lobby, public restrooms, dressing rooms, and office space. The old dressing rooms are now used as a weight room, aerobics room and offices.
The structure of the main pool room consists of 6 main glu-lam girders spanning the full width of the room in the east-west direction and bearing on 2 foot x 2 foot concrete block pilaster columns. The spacing of these girders is 20 feet. There are eleven intermediate glu-lam beams at 6 foot on center spacing that span between each main girder and the two exterior walls at the north and south ends of the structure. The ceiling and roof consists of 2X6 tongue and groove laid flat with ½-inch plywood sheathing on top and then the roofing membrane, which consists of a built up roof at the flat portions and asphalt shingles over the two clerestories which are constructed between girders 2 and 3 and 4 and 5 when starting the numbering system at the north wall (See figure, Appendix A). The clerestories have a 4:12 roof slope with windows on the south walls. The north and side walls consist of 2x6 studs at 16" on-center constructed on top of the main girders or on the intermediate beams. There are glu-lam headers over the windows.
The east exterior and west interior walls are constructed with 8 inch reinforced concrete block fill-in walls between the pilasters. The north and south bearing walls are constructed of 8 inch reinforced concrete block. The exterior surface is stucco.
METHOD OF INVESTIGATION
GENERAL:
On July 30, 2006, Timothy L. Grim, P.E./S.E., Ryan Plank, EIT and Michelle Mitchell made a visual and non-destructive inspection of the structural elements of the pool room area of The Ontario Aquatic Center at 790 S.W. 3rd Avenue, Ontario, Oregon.
EXTERIOR:
We visually inspected the exterior portion of the roof and observed the following items. See the figure in Appendix A for locations
A. Expansion joints on the west wall had lost most of the caulking materials that had been installed.
B. Caulking material around the window glass in the clerestories was cracked, deteriorated and at several locations, nonexistent. The fade between windows on clerestory #1, west quarter point was detached.
C. Minor rust is occurring on a majority of the exposed metal around the clerestories. Fascia material, gutters, window frames and flashing material have some rust at various locations with some screws not being present.
D. Substructure sheathing under asphalt shingles on clerestories has visible deflection from point loads of a person walking on it. The deflection transmits through the structure in such a way that it is visible on the underside of the 2X6 tongue and groove ceiling material below. No such deflection is detectable in the flat portions of the roof. The 2x6 tongue and groove are spanning east to west across the intermediate beams in both locations.
E. Built up roofing material below the windows of the clerestories have cracked. Moisture penetration through cracks is not evident at this time.
F. The exterior east wall expansion joints have deteriorated caulking material which appears to be capable of allowing moisture penetration. The deterioration is 2/3 to 3/4 of the height of the wall starting at the top.
G. Transverse cracks along the top and projecting down on the east side of the west parapet wall of the pool room structure occur at approximately 2-foot intervals. _
H. We completed a visual inspection of the exterior walls. Besides the deterioration of the expansion joints noted above, minor vertical cracks were observed in the concrete foundation wall. No cracks were seen in the stucco finish on the walls.
INTERIOR WALLS AND FLOORS:
We inspected the interior surfaces of the concrete block walls including the block pilasters supporting the main glu-lam girders. We made the following observations. See the figure in Appendix A for locations.
A. Pilaster #2 along the west wall: caulking is pulled away between the wall and the pilaster
1 at the southeast corner of the element.
B. Hairline cracks exist in the north bearing wall and primarily follow mortar joints.
C. Minor hairline cracking exists in the west wall between pilaster #4 and the office window. There is also a diagonal crack that propagates from the girder bearing seat.
D. Caulking that was installed between pilaster #5 and the west wall has broken loose along the north side of the pilaster.
E. Hairline cracks are visible in mortar joints between the mechanical room door and the
southwest corner of the building.
F. There are diagonal cracks that follow the mortar joints at the southeast corner of the structure
G. There are hairline cracks in the fill-in walls between pilasters along the east wall in various mortar joints.
H. Caulking has also pulled away from the joints between pilasters #2 (south side) and #5 (north side) and adjoining block walls.
I. There are moderate horizontal cracks with spalling occurring in the concrete curb that is between the concrete pool deck and the window frames installed as the south wall of the building.
J. The pool deck is cracked in a couple of locations: between the training pool and the main pool at the west end; a north-south crack at the northeast corner of the training pool; and several hairline fractures.
INTERIOR CEILING:
The five main girders were visually inspected at several locations along their length. At each location we recorded the moisture content; sounded for decay; visually looked for delaminations; and inspected the visible connections for intermediate beams. Bearing connections were inspected for rust and deterioration of steel, possible mold infestation and dry rot under steel brackets. Signs of excess stress were noted. Items observed are listed below. See the figure in Appendix A for locations and moisture contents.
A. West end of girder #1 at bearings: minor rusting of nuts and a nut is loose on the south side anchor bolt into the pilaster.
B. Brackets for intermediate beams on girder #1 have a higher amount of rusting present on the west end (over the hydro pool)'than the remaining connections. There is no change in sounding of the girder at the connections. It appears to have localized additional moisture at these locations.
C. Girder #4, south side, west half of beam has a localized indent at the top of the girder which appears to have occurred during construction.
D. Several bearing plates and brackets at the east end of the girders are rusting with deterioration of the horizontal surfaces of the brackets. The rusting would be classified as moderate to extreme. Anchor bolts and corresponding nuts for the bearing plates are • rusty and probably not operable.
E. No dry rot (decay) was observed at the bearing areas of the main girders or the intermediate beams.
F. The moisture content measured in the girders on July 30, 2006 are as follows: #1: Range from 7.1% to 11.5%
#2: Range from 8.5% to 14.8%
#3: Range from 9.4% to 15.7%
#4: Range from 10.3% to 12.4%
#7: The moisture content measured in the intermediate beams ranged from 8.9% to 12%.
G. The girders slope 16 inches from west to east and there appears to be more water staining at the east end of the girders in comparison to the west end. The bracket and connection of the column for beam number 6 at girder number 3 has moderate rust and flaking of the steel surface. (See Appendix B, pictures 66 through 70)
INTERIOR LEDGERS AND MISCELLANEOUS:
Along the perimeter of the pool room at the elevation of the roof, there are glu-lam ledgers. The ledgers north of girder 6 measure 31/ 8 x 12 inches and the ledgers south of girder 6 measure 31/a x 13½ inches. The ledgers are attached to the east and west wall with anchor bolts at 4- foot centers, and 4 bolts each between the intermediate glu-lam beams. Observations concerning these ledgers are listed below. See the figure in Appendix A for locations.
A. The measured moisture content in the ledger, between girders 1 and 2, along the east wall, ranged from a high of 32% to a low of 14.8%. Sounding of the ledger does not indicate any dry rot (decay) present.
B.The ledger along the north wall between intermediate.beams 10 and 11 has rusty nuts and bolts, while other bolts appear to be painted. Also, it appears that there was moisture penetration into the ledgers at the bolts. However no dry rot (decay) was observed.
C. Between beams 7 and 8, at the north wall, we observed one bolt that was broken.
D. Brackets, threaded rods and bolts that are supporting the mechanical duct work are rusty but appear to be performing the function they were intended to be doing.
INTERIOR WALL CAVITIES:
We cut through the Sheetrock wall board in fire locations to expose the wood structure underneath to investigate the possibility for dry rot (decay) and/or the presence of mold. The following describes the locations of those investigative holes and the findings that were observed. See the figure in Appendix A for locations.
1. The first investigative penetration is located under intermediate beam 3, space C, north end.and it exposed the area between the bottom of the beams and the top of the girder. Solid 2 inch thick wood plates were found. No dry rot was visible. Minor rust was observed in the bracket holding the intermediate beam. The Sheetrock corner bead has deteriorated to nothing. Suspected mold was observed on the back surface of the painted Sheetrock. (See Appendix B, pictures 50 through 53)
2. The second investigative penetration is located under intermediate beam number 8, space C, south side, between the top of girder 3 and just below the window sill. It exposes the wood column that supports the beam and transfers the load to the girder. Minor to moderate center check was observed within the wood column in the exposed area. Dry rot was not observed in any of the exposed wood members. The steel side bracket portion inside the wall was moderately rusted, but the exposed section visible on top of the girder had very minor amounts of speckled rust present. The connection appeared tight with no visible dry rot or poor soundings in the top of the girder. The removed portion of the Sheetrock appeared to have mold on the inner surface. (See Appendix B, pictures 60 through 65)
3. The third penetration is located between beams 3 and 4, south side of girder number 4. This penetration exposed the area between two studs and the bottom plate of the wall. Dry rot was observed in the bottom plate, which covered as much as one quarter of the Width and three quarters of the depth of the plate. There was evidence that moisture
had been running down the exterior portion of the studs. Batt insulation and moisture barrier were present in the space between the studs. (See Appendix 8, pictures 88 through 95)
4. The fourth penetration was made at the window sill of the clerestory above girder number 5. The plywood under the Sheetrock appeared to have two layers in which the top layer was totally rotted and approximately one-half of the 2nd layer was rotted and the Sheetrock is disintegrating. Material that was removed from the area appears to have mold on the back surfaces of the Sheetrock. (See Appendix 8, pictures 97 through 100)
6. The last penetration was made on the east wall of the clerestory between girders 4 and
7. The Sheetrock was removed between two studs, above the bottom plate and below a horizontal block member. Insulation was not found in the open space. A minor amount of rot was present in the penetration along the exterior plywood and the bottom plate. There was evidence that moisture has been present in the open space running off the exterior sheathing and the exterior section of the studs.
MOLD TESTING:
We observed what appeared to be scattered mold colonies on the back side of the Sheetrock
where we opened the wall cavities and on some of the wood which was exposed within the wall cavities. We did not observe any apparent mold on the exterior of the walls or glu-lam members. We submitted two samples for mold identification testing. The tests were completed by Aerotech Laboratories in Phoenix, Arizona. No mold was detected in the sample from the surface of the wood in the wall cavity. However, two types of mold were detected on the back side of the Sheetrock: Aspergillus/Penicillium like mold and Chaetomium. These molds are common in our environment, and paper products often provide a good growth media for these molds
CONCLUSIONS
After a thorough review of the structure, we have reached the following conclusions:
A. The six main glu-lam girders are structurally sound. No dry rot (decay) was found. No delaminations or evidence of excess stress was observed. The moisture contents as measured on July 30, 2006 were below the allowable limit of 16%.
B. The eleven intermediate glu-lam beams in each of the seven bays are structurally sound. No delaminations or evidence of excess stress was observed. No dry rot (decay) was found. The moisture content as measured on July 30, 2006 was below the allowable limit of 16%.
C. The glu-lam wall ledger along the east wall between main girder 1 and 2 has moisture content in excess of the allowable limit of 16% as measured on July 30, 2006. No delaminations or evidence of excess stress was observed. Sounding of the ledger was good and no decay was observed.
D. Dry rot (decay) was found in the wood framed walls for the clerestories above the main girders and the intermediate beams at exploratory penetration 3 and 5.
E. Dry rot (decay) was found in exploratory hole #4 located in the side area below the
windows in the south wall of clerestory number 2.
F. Water is entering the wall cavity below the windows in the clerestory. The window glazing appears to be leaking, and this might be_the primary source of this water. However, it is likely that a significant amount of moisture condenses on the windows and flows down onto the window sills particularly during cool and cold weather
G. Bearing brackets for main girders on top of block pilasters are structurally sound. No cracks or deterioration of welds was observed. However, minor to moderate rusting was found.
H. Connection brackets between intermediate beams and main girders are structurally sound. Minor rust was observed but no major deterioration was discovered.
I. Reinforced concrete block walls and pilasters are structurally sound. Minor cracks were observed.
J. Expansion joints in exterior walls are not sealed and are allowing moisture penetration through the wall.
K. Roof structure between intermediate beams on the sloped portion of the clerestories and on the flat portions of the remaining structure, appear to be structurally sound. Visible deflection occurs on the sloped portion of the clerestory while walking on the structure but not on the flat portion of the roof. The point load from a person walking on the roof is several times greater than the design roof load. This minor deflection does not constitute a structural defect.
L. The foundation appears to be structurally sound as no major crack or settlement was
observed.
M. The glazing of the windows on the south side of the clerestories has failed and appears to allow moisture penetration at those locations.
RECOMMENDATIONS
1. Replace window sills of the clerestories and replace the glazing (caulking) on all of the windows to prevent further moisture penetration into the walls. The new sills should be sloped at a minimum of 1:12 to drain any condensation to the interior face of the wall. A drip edge should be installed to keep the water from running down the face of the wall. The sill should be covered with waterproof flashing to protect from moisture.
2. Clean out existing material in the exterior wall expansion joints and re-caulk with new material to prevent moisture penetration into and through the walls.
3. Clean the rust from all the connection and bearing brackets for the main girders and intermediate beams. Anti-rust paint needs to be applied to prevent additional deterioration.
4. Monitor moisture content in the girders and beams during a winter in which additional condensation is present.
5. ·Install a moisture barrier and insulation in east and west walls of the clerestories.
6. Two mold types were identified on the back of the Sheetrock within the wall cavity: Aspergillus/Penicillium-like and Chaetomium. These are common molds which typically produce low health risk when they are contained, such as within a wall cavity, and not exposed to humans. However, if the mold develops on any surfaces which are exposed to humans, air testing should be completed by a qualified industrial hygienist to evaluate whether a significant risk is present. Likewise, when structural repairs are completed which require will expose the known mold within the wall cavity, these repairs should be
completed by a contractor who is qualified to safely handle mold as well as the structural• repairs
7. Monitor the dry rot in penetrations #3 and #4 once a year. If it progresses to a point that it effects the glu-lam girders, replace the bottom plate, studs and sheathing. These elements are non-structural.
LIMITATIONS
We have prepared this report for use by the City of Ontario, Oregon. This report is not intended for use by others and the information contained herein is not applicable to other sites. Our report, conclusions and interpretations should not be construed as a warranty of the structure conditions.
The scope of our services does not include services related to construction safety precautions and our recommendations are not intended to direct the contractor's methods, techniques,· sequences, or procedures, except as specifically described in our report for consideration in design.
Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of structural engineering in this area at the time this report was prepared. No warranty or other conditions, express or implied, should be understood.
