mary anne smith - foundation waterproofing structural survey

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STRUCTURAL CONDITION ASSESSMENT REPORT

EXTERIOR BRICK WALLS, FOUNDATION,

AND FLOOR FRAMING

Smith HallUniversity of North Carolina

Chapel Hill, NC

Prepared for:UNC-CH Architectural & Engineering ServicesFacilities Condition Assessment Program

Prepared by:Atlas Engineering, Inc.2245 North Hills Dr., Suite I, Raleigh, NC 27612919-420-7676

May 29, 2003


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1.0 Executive Summary

Atlas Engineering, Inc. performed a structural survey to assess the condition of SmithHall on May 9, 2003. As part of the survey, we identified areas of damage anddeterioration, assessed the floor live load rating for code compliance, and made general

recommendations for structural repairs to the building. We compared the currentcondition with established criteria based on the North Carolina State Building Code, 2002Edition Chapter 16.

The exterior brick has minor stair-step cracks at the two exterior stairways, and betweenthe basement and first floor windows near each of the four building corners. Thesemasonry cracks are not structurally significant but should be repointed.

One interior stairway at the basement level shows wood damage, reportedly by termites,that is severe enough to be a structural hazard. Water leaks near the northeast entrancehave likely damaged several floor joists at the first floor level, through long-term decay.

A wood-framed doorway in the basement has also been damaged by decay. These areasof isolated framing damage are shown on the attached drawing.

None of the floor framing members could be inspected due to the heavy plaster ceilingfinishes. Based on our review of the original plans and our capacity calculations, webelieve that the floor framing at the corridors and offices meet the code-required live loadcapacities.

However, we could not locate any design information on the support for the second andthird floor areas above classrooms 107 and 202. The 1960s renovations removed load-bearing walls in these rooms that supported the floor areas above. We were not able to

observe the replacement supports or make capacity calculations, and cannot confirm thatthe floor areas above classrooms 107 and 202 meet the Code criteria for floor live loadcapacity.

We recommend immediate repair of the termite-damaged stair and water-damageddoorway in the basement. We strongly suspect floor framing decay at the first floor nearthe northeast entrance, and recommend selective demolition of the basement ceiling toinspect and repair these first floor joists. The foundation wall in this area should bewaterproofed.

We recommend selective demolition of ceiling areas in classrooms 107 and 202, to

expose the supports for the floor framing above. This will be required if the floor liveload capacity is to be confirmed in the areas above 107 and 202.

We estimate the cost of the above repair work at $33,800. The Smith Building should bere-inspected at intervals of two to three years.

Report on Structural Condition Assessment WRN 558578

Exterior Brick Walls, Foundation, and Floor Framing - Smith Hall Building No. 128

Prepared for University of North Carolina at Chapel Hill - Facilities Condition Assessment Program

Prepared by Atlas Engineering, Inc., 2245 North Hills Dr., Suite I, Raleigh, NC 27612May 29, 2003 Page 1


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2.0 Introduction

The purpose of the structural survey was to assess the condition of the brick veneer,foundation, and floor framing of the Smith Building, and to compare the currentcondition with established baseline criteria. Additionally our goal was to identify areas

of damage or deterioration, evaluate the safety and durability of the structure, assess thefloor live load rating for code compliance, and recommend repairs to the structure.

We first obtained available copies of drawings pertaining to the construction of thebuilding and any subsequent repair work. We reviewed the drawings to determine thetype of construction, structural layout, and to identify specific structural members criticalto the walls, floors, and foundations.

A Professional Engineer, familiar with typical building distresses, made structuralobservations at the site on May 9, 2003. Basic documentation included photographs andwritten notes. Clearly damaged structural components were documented, as well as less

obvious indications of structural distress, such as damaged finishes, patterns of cracks,and excessive deflection.

Our survey included visual observations by an experienced engineer, and included onlystructural-related issues. No finishes were removed or excavations made to reveal hiddenconditions, and no material or load tests were conducted as a part of our current scope.The survey did not include inspection of electrical systems, egress, fire-suppression orfire rating of building components, or review of handicap accessibility. Our costopinions for repairs must be considered as preliminary, as no repairs have been designedand no material quantity take-off has been performed at this time.

3.0 Testing Program

No testing was performed as part of this structural assessment. Based on ourobservations, and the lack of sufficient information regarding the floor framing systemsabove rooms 107 and 202, we recommend selective demolition of the ceilings in theserooms to verify the structural supports.

4.0 Data Collection And Documentation

The information collected regarding this structure included copies of the originalstructural drawings for this building. A list of drawings and reports reviewed arepresented at the end of this report. Copies of the drawings were made from the 1901record drawings on file at the UNC Facilities Services Plan Room located in the GilesHorney Building.






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Observed field conditions were documented with both digital photographs and writtennotes. The notes were recorded by the inspecting engineer in a bound field book.

5.0 Description of Structure

Smith Hall currently houses the Academic Technology & Networking Service in thebasement, Statistics Department on the first floor, and Operations Research on the secondand third floors. Originally constructed in 1901 for use as a student dormitory, it wasconverted to office and classroom use in the 1960s and most recently renovated in 1996.

The Smith building is a four-story brick and timber building measuring approximately45 by 130 in plan with the long dimension running perpendicular to East CameronAvenue. The building construction includes load bearing exterior and interior brickmasonry walls, load-bearing stud walls, timber floor joists, and a steep-sloped hippedslate-covered roof. Details regarding the structural system supporting floor loads overthe classrooms 107 and 202, which were created during renovations performed during the

1960s, were not shown on available plans and could not be determined from inspection.Selective demolition at plaster walls and ceilings would be required to confirm the floorframing arrangements.

The brick masonry walls are three wythes (layers) thick. The interior and exteriormasonry walls extend from the floor slab to the third floor level. Original designdrawings indicate that all the masonry walls bear on footings of widened brick masonryconstruction.

The floor framing consists of 2 by 12 wood floor joists spaced 16 on-center andspanning front to back across the central hallway and right to left over the rooms that

flank the hall. Span lengths are typically 11 to 16 feet in offices and classrooms and 7to 9-6 in the hallways. At the exterior walls, the joists bear in beam pockets. Thebasement floor plan located at the end of this report is based on the current floor plan.

The roof is a steep slope hip roof formed by 2 by 8 rafters spaced 20 on center with 1by 8 horizontal tension member fixed 5 down from the ridge line. Vertical loads arecarried by 6 by 8 purlins supported on stud walls and by the exterior masonry walls.

Floor finishes include carpeting and vinyl floor tiles. The interior walls consist of paintedplaster over metal lath and painted gypsum wallboard. The ceilings are insulatedacoustical panels with metal grid suspended below the original plaster ceiling.

The load paths for this structure are conventional. Vertical roof loads are collected by thepurlins and delivered to the interior stud walls and upper courses of the exterior masonrywalls. Floor loads are collected by the timber floor framing systems and delivered tointerior stud walls and pocket or corbel bearings at the interior and exterior masonrywalls. The un-reinforced masonry walls deliver loads to shallow footings running along






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each wall. It is possible that steel girders were added during renovations performed in the1960s that combined smaller room into classrooms 107 and 202.

Lateral wind and seismic loads are resisted by the diaphragm action of the floor levelsand the shear wall capacity of the interior and exterior masonry walls.

For overall building stability, the critical members include the interior and exteriormasonry walls, and wood floor and roof members.

6.0 Site Observations

Exterior Brick WallsPhotos 1 to 3 show exterior views of the east, west, and south walls of the building.Weather exposure has faded some brick and roof drainage has stained some brick.

The exterior brick wall had stair step cracks near the building corners, located between

the basement and first floor windows. Photos 4 and 5 show the cracks located on eitherside of the southwest corner. Probing the mortar joints with a small knife, weencountered areas of soft tan mortar adjacent to areas of hard mortar. In addition, atseveral windows the mortar finish used to provide the appearance of stone lintels wascracked.

Foundations

The spread footing foundations are buried more than 5 below exterior surface grade andcould not be inspected from either inside or outside the building. Cracks near thebuilding corners were likely caused by differential settlement but have widths less than without any evidence of recent movement. The concrete exterior stairways located at

the southeast and northeast corners appear to have settled more than the building causingthem to separate slightly from the building. Photo 6 shows the exterior stairs located atthe northeast corner. The section of downspout pipe shown missing in photo 6 hasreportedly been removed for repair.

Interior Termite and Water Damage

Photo 7 shows water damage to the first floor wall located near the northeast entrance,and photos 8 and 9 show water damaged ceilings and walls located in the basementadjacent to the northeast entrance. We could not directly inspect the structural framingmembers in the vicinity of ceiling damage shown in photo 8, but it is likely joists beendamaged sufficiently by decay to decrease their structural capacity. Photo 10 shows a

water damaged basement doorway. A small area of similar damage was also observed inthe exterior basement doorframe. Photo 11 shows water damage observed on the ceilingof room 203, which was apparently caused by a roof leak.

Photo 13 shows the stairway from basement to the first floor, which has reportedly beendamaged by termites. While we understand exterminators have eliminated the termites,






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no repairs have been made to the damaged stairs. The basement floor plan drawing at theend of this report shows the locations of termite and water damage.

Floor FramingThe 1

st, 2

nd, and 3

rdfloors appeared fairly level and felt firm under foot traffic. Photos 14

and 15 show views down the 2

nd

and 3

rd

floor hallways. While the 3

rd

floor appeareddepressed along the left wall, tile was uncracked. The depression is likely the result oflong-term creep (or set) of the wood members.

7.0 Analysis

We analyzed the floor framing capacity performance criteria using live loads given in theNorth Carolina State Building Code, 2002 Edition, Table 1607.1. The specifiedminimum uniformly distributed floor live load for the first floor corridors is 100-psf, andfor 2ndand 3rdfloor corridors is 80-psf. The required minimum floor live load for officesis 50-psf, and for classrooms is 40-psf.

From the record drawings, we were able to determine the original floor framing systemsand connection details in corridors and offices. Based on our analysis and the observedcondition of these floors, it is our opinion that these floor structural systems meet the NCBuilding code requirements.

The renovations in the 1960s included removal of load-bearing stud walls in classrooms107 and 202. The stud walls had supported the joists in the floor framing above theserooms. The renovation work had to include installation of new support girders, possiblysteel beams, to replace the support of the stud walls. No plans could be located to showthis work, and the new supports are hidden from view by the plaster ceilings. We were

not able to confirm the live-load capacity for the floor areas above these rooms. Loadcapacity calculations cannot be made for these floor areas, without exposing, measuring,and inspecting the support members added in the 1960s. This will require selectivedemolition of the plaster ceilings.

8.0 Conclusions and Recommendations

In the basement, termite damage has structurally damaged the stair to the first floor, andwater infiltration has caused plaster damage at walls and wood decay at doorways. Waterinfiltration has likely caused decay damage to several first-floor joists near the northeastentrance, as well. These damaged parts should be repaired. The water leaks at the

foundation wall near the northeast entrance should be found and repaired.

Brick cracks at the exterior are minor and are not structurally significant, but should berepointed to prevent water entry and future damage to the interior. Soft mortar near thesecracks should be raked out and repointed.






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We recommend selective demolition of the plaster ceilings at classrooms 107 and 202, toexpose the floor joist supports installed during the 1960s renovation. Once these areexposed, the supports can be measured and inspected, and the floor live load capacity canbe confirmed for the floor areas above these rooms.

We recommend a structural re-inspection of the building every two to three years.

Recommended Repairs

Priority Item Unit Cost Quantity Total

1 Replace wood stair frombasement to first floor

$1,000/day 2 days $2,000

2 Selective demolition ofbasement ceiling to inspect andrepair probable decay damage

at first floor joists adjacent toNE entrance

$1,000/day 3 days $3,000

3 Selective demolition ofceilings @ 107 & 202, andengineering assessment offloor load capacity

$4,000 $4,000

4 Waterproof foundation walladjacent to NE entrance

$21.00/sf 240 sf $5,040

5 Replace 2 basement doorways $1,000/day 3 days $3,000

6 Repoint brick near corners $3.50/sf 714 sf $2,500

Subtotal $19,540Overhead (10%) & Profit(10%)

20% $3,908

Contingency 20% $4,690

Design Fee 20% $5,628

Total $33,766

These costs must be considered preliminary in nature.






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Photo 1: Overview of the building looking west.

Photo 2: Overview of the building looking east.






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Photo 3: View of buildings south side.

Cracks

Photo 4: Photo of south wall at southwest corner showing cracks in brick wall indicating

settlement.






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Crack

Photo 5: Photo of west wall at southwest corner showing cracks in brick wall indicatingsettlement.

Photo 6: Photo of Entrance at Northeast Corner showing area of water leaks (arrow).






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Photo 7: Photo of water damage on interior wall at Northeast entrance.

Photo 8: Close-up view of water damage in basement wall below Northeast entrance.






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Photo 9: Photo of water damage in basement housekeeping room below Northeastentrance.

Photo 10: Photo of water damage to cased opening in basement.






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Photo 13: Photo of basement stair with termite damage.

Photo 14: Photo showing carpeted 2nd

floor hallway.






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Photo 15: Photo showing tiled 3rd floor hallway.






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List of Drawings and Reports Reviewed

List of Drawings

1. Mary Ann Smith Dormitory Building; Frank P. Milburn, Charlotte, NC; undated;located at UNC-CH Facilities Plan Room Vault No. 6.

2. Current floor plans transmitted electronically.

Indicates As-Built drawing set.

List of Reports

1. No previous reports were found regarding this building.




Prepared by Atlas Engineering, Inc., 2245 North Hills Dr., Suite I, Raleigh, NC 27612May 29 2003 Page 15

mary anne smith - foundation waterproofing structural survey

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