STRUCTURAL ASSESSMENT OBSERVATION REPORT

Transcription

1 Consulting Engineers THORSON BAKER & Associates, Inc West Streetsboro Road (330) phone Richfield, Ohio (330) fax STRUCTURAL ASSESSMENT OBSERVATION REPORT Client: Weber Murphy Fox Project No: Site Observation By: Mike Thorson Project: Girard Middle School Date of Observation: June 15, 2012 Project Site: Girard, PA Date of Report: June 29, 2012 PURPOSE: A site visit of the referenced site was conducted on June 15, The purpose of the visit was to structurally assess the condition of the existing Girard Middle School campus. GENERAL The Girard Middle School consists of the original school located to the west end of the facility, dating to approximately 1917 and two additions. Immediately adjacent to the east is a three story addition constructed in East of the 1953 addition is a one and two story addition constructed in The original school building constructed in 1917 is a two story wood framed structure. The floor and roof structure were not exposed to view and could not be observed. The exterior walls and corridor walls are load bearing masonry with wood floor joists spanning north and south from the exterior walls to the interior corridor walls. The 1953 addition is a steel framed building in the three story classroom structure and one story steel framed structure in the gymnasium and cafeteria wings. The structure is column supported with steel joist floor and roof structure with a concrete slab on wire lathe. This structure would qualify as non-combustible construction. The lowest level of the addition housing storage and industrial arts is a half story below grade. The basement walls are cast-in-place concrete The most recent 1993 addition is also a one and two story steel framed structure. Nowhere was the structure exposed to view however one can safely assume the floor structure is concrete on metal deck and the roof is metal deck on steel joist. This structure would also be considered non-combustible. OBSERVATIONS 1917 Building The exterior brick masonry walls are in need of significant repointing. In numerous locations, particularly around windows mortar has cracked and is undoubtedly permitting infiltration of wind driven rain (Photos 1 & 2). Lintels show signs of surface corrosion. The foundation walls exhibit significant cracks and require filling with a sealant (Photos 3 & 4). These cracks are vertical most likely indicating they are associated with drying shrinkage. It would appear that the walls may not be reinforced given the width of the cracks. The joints at the building corners and much of the stone accents require repointing (Photo 5).

2 Page 2 The outer brick wythe above the windows on the third level appears to be walking off of the lintels above the windows possibly creating an unsafe condition (Photos 6 & 7). It is not uncommon for structures of this vintage to not have a physical attachment between the exterior walls and the structure. Wind not only exerts a windward force but also a suction or leeward force which pulls an exterior wall away from the building. This lack of physical attachment in coordination with leeward wind could result in this condition where the exterior brick wythe is projecting as much as 2 ½ inches over the edge of lintel. A maximum brick overhang of ½ to ¾ inches is recommended. The lack of a direct positive attachment of the wall to the structure can result in longterm maintenance issues at well as in an extreme situation, loss of an entire section of wall in high winds Structure Exterior walls of this addition are a brick veneer with an air space between the veneer and a concrete masonry back-up. The veneer has weep tubes at regular intervals to drain condensation which forms in the air space between the veneer and block backup. These weeps however are filled with wasp mud and are not functioning as indicated. Similar to the 1917 structure the exterior walls do not appear to have been adequately attached to the structural frame. External wall anchors have been post installed in an attempt to correct this deficiency (Photos 8 & 9). In numerous locations the brick veneer is observed to overhang the lintels by as much as 2 ½ to 3 inches (Photos 10 & 11). The third floor level lintels appear to not have been properly flashed. All of these issues lead to water infiltration and deterioration of the masonry walls. The wall at the northwest corner of the 1953 addition where it abuts the 1993 addition has a vertical crack extending from approximately the second floor to the roof. This crack has caused a separation allowing water infiltration. In addition, the corner column at this location bears on the basement wall which also exhibits spalling and a significant crack. The exterior walls on the gymnasium have pulled away from the structure as much as 3 ½ inches and have been externally tied back to the structure by installing external whalers or wind columns (Photos 12, 13 & 14). All of the above issues establish a concern that the exterior walls of the 1953 addition were not adequately anchored. The same concerns identified in the original 1917 building are a concern with the 1953 addition. Numerous cracks were observed at building corners (Photos 15 & 16). Sealant at masonry control joints is also dry and cracked and in need of repair (Photo 17). Consistent with the comments of the school board administrators and maintenance staff, moisture infiltration into the building is undoubtedly an issue. The basement walls were also observed to be cracked at 8 to 10 feet on center (Photos 18, 19 & 20). Substantial ground water has been observed entering the basement at a number of these cracks. The top of the basement walls do not extend to the first floor and therefore are laterally unbraced (Photo 21). In general, with the exception of the vertical shrinkage cracks, the walls appear to have functioned adequately. The design of the basement walls however, is structurally unsound and may have attributed to some of the issues observed Addition In general the 1993 addition appears to be in good condition, with the exception of a roof leak near the administrative offices. Exterior windows were appropriately flashed, weeps were present and functioning. Control joints in the exterior walls were at appropriate intervals. Sealant in the masonry control joints due to age was dried out and in need of replacement, otherwise the 1993 addition was in good condition. Conclusion The condition of the original building and the 1953 additions are in marginal condition even in light of their age. Both structures have significant issues associated with the exterior building envelope. As noted in the report, in general the exterior walls are not appropriately attached to the structural frame, the exterior wythe of brick extends precariously 2 to 3 inches beyond the edge of window lintels and lintels exhibit some corrosion and are not properly flashed.

3 Page 3 In addition the brick masonry walls and cast stone accents require extensive re-pointing and repair. This will also require extensive lintel extensions and/or replacement. The exterior walls of the gymnasium, although they have been restructured and now have a physical connection to the building, are out of plumb and in need of some additional structural and cosmetic repairs. The northwest corner at the interface of the 1953 addition to the 1993 addition where the wall has separated as previously described will require significant restructuring. The basement walls of the original 1917 building as well as the 1953 addition require significant crack repair. The perimeter requires excavating to waterproof the perimeter walls and install a perimeter drain. Copings at the parapets were observed to be loose in numerous locations requiring removal and replacement. In summary there is significant work required in the original building and the 1953 addition to make the building envelope watertight and secure to the building frame. One additional consideration is that the original 1917 building is a wood framed structure and is combustible. Combustible construction typically is not permitted in new construction for educational buildings. The 1993 addition is in good general condition requiring only caulking of the exterior control joints and repair of a roof leak over the administrative offices.

4 Page 4 Photographs Photo 1 Photo 2 Photo 3 Photo 4

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