SECTION 3 ONM & J STRUCTURAL ANALYSIS

Transcription

1 Historic Boynton Beach High School Existing Building Assessment City of Boynton Beach February 10, 2011 SECTION 3 ONM & J STRUCTURAL ANALYSIS

2 STRUCTURAL ENGINEERS SPECIAL INSPECTORS STRUCTURAL CONDITION ASSESSMENT & STRUCTURAL FEASIBILITY STUDY OLD BOYNTON BEACH HIGH SCHOOL Boynton Beach, Florida Project No.: February 7, LA Kirksey Street Suite 200 West Palm Beach, FL Phone: (561) Fax (561)

3 TABLE OF CONTENTS Page Number I. Scope 1 II. Project Description 2 III. Executive Summary 3 4 IV. General Observations 5 8 A. Exterior 1. North Elevation 2. East Elevation 3. South Elevation 4. West Elevation 5. Roof B. Interior 1. Roof Framing 2. Second Floor Framing 3. Ground Floor Framing 4. Exterior / Interior Bearing Walls 5. Foundation V. Feasibility Study 9 12 A. Codes and Standards B. Design Loads C. Foundation System D. Wall Framing System 1. Exterior 2. Interior E. Floor Framing System 1. Ground / Second Floor Classroom Wing 2. Second Floor Auditorium / Gymnasium Wing F. Roof Framing System 1. Classroom Wing 2. Auditorium / Gymnasium Wing VI. General Notes 13 VII. Exhibits A. Photographs B. Typical Reinforcement Details C. Photo Key Plan

4 SCOPE Pursuant to your request, we performed a visual site visit review and a cursory design analysis on the Old Boynton Beach High School located on Ocean Avenue, Boynton Beach, Florida. The purpose of the investigation was to perform a Structural Condition Assessment of the two-story building and to provide a schematic narrative out-lining the general structural improvements (exterior walls, roof / floor framing systems, foundations, etc. to resist gravity / wind loads) required for the current Florida Building Code. The inspection methods used to formulate our conclusions were based on a visual review of the exterior / interior of the building. In addition, a cursory design analysis was performed to determine what general repairs / modifications will be required to bring the overall structure up to current code (The Florida Building Code, 2007 Edition) for gravity / wind loads. This cursory design analysis will provide us with additional information to make a determination as to the feasibility of upgrading the existing building structure. The cursory design analysis used to formulate our conclusions was based on a plan review of the original building drawings, dated July 15, 1927 and information provided by REG Architects, Inc. Various areas of the exterior / interior were available to expose the framing of the roof / floor structure. No destructive testing of materials / components was undertaken. Our evaluation is based only on visual examination of the areas, which were opened on the date of our visits. 1

5 PROJECT DESCRIPTION The building consists of a two-story terracotta / wood frame structure of approximately 28,500 square feet designed as a high school in a Mediterranean revival style. The facility was originally constructed in the late 1920 s. The exterior envelope of the building consists of painted textured stucco cladding, cast stone trim, arches, aluminum / glass windows and two main entries on the South (front) elevation. The roof is clad with a built-up roofing membrane system with sections of barrel tile roofing in the mansard areas. The structural roof framing system in the classroom wing consists of stick built wood trusses, wood rafters, wood plank sheathing and a built-up membrane roof cladding system. In the auditorium / gymnasium wing the structural roof framing system consists of structural steel riveted bow trusses, heavy timber purlins with wood plank sheathing. Steel I beams, wood rafters and wood plank decking are present over the stage area of the auditorium / gymnasium. The classroom wing second floor structural framing system consists of wood floor beams, diagonal wood plank sheathing and finished tongue and groove hard wood flooring. The structural floor system in the auditorium / gymnasium wing consists of concrete slab / joist system supported on concrete beams and columns. The ground floor consists of a 4 reinforced concrete slab-on-grade with some sections framed with wood floor beams, diagonal wood plank sheathing supported on reinforced concrete foundation walls. The foundation system of the building consists of reinforced concrete walls, continuous and isolated spread footings. The building is equipped with sanitary sewer, storm water drainage, domestic water, electrical and phone services. Parking is provided on the West and North elevations of the building. 2

6 EXECUTIVE SUMMARY The Old Boynton Beach High School building is in fair structural condition, albeit, having areas of noted deterioration / damage requiring repair and / or replacement. The building envelope walls, consisting of painted light-textured stucco cladding on hollow terracotta tile masonry, aluminum / single-glazed glass windows, were observed to be in fair condition with no structural deficiencies apparent. The painted stucco cladding was also noted to be flaking. The roof cladding (consisting of a built-up membrane system and a clay tile barrel roof system in the mansard areas) was not observed during our site visit. We recommend that a roofing specialist be consulted to review in detail the condition of the roof claddings. The structural roof framing system in the classroom wing of the building, consisting of stick built wood trusses, wood roof rafters, wood plank sheathing, supported on the terracotta tile masonry / wood-framed stud bearing walls, was observed to be in good condition with some isolated areas of damage / deterioration from severe, long-term water / moisture intrusion and exposure. These isolated areas of damage / deterioration will require repair, removal and / or replacement. In the auditorium / gymnasium wing of the building, the roof framing system, consisting of structural steel riveted bow trusses, heavy timber purlins and wood plank sheathing, was noted to be in good condition with no apparent structural defects observed. Steel I beams, wood rafters and wood plank decking over the stage area of the auditorium / gymnasium require further investigation due to being inaccessible. The classroom wing, second floor framing system, consisting of wood floor beams, diagonal wood plank floor deck and finished tongue and groove hardwood flooring, was observed to be in good condition with no structural defects apparent, albeit, in the isolated observed areas of long-term water / moisture damage / deterioration / rot. These isolated areas of structural damage / deterioration will require removal, repair and / or replacement. The ground floor structural framing system in the auditorium / gymnasium wing, consisting of a reinforced concrete slab / joist system was observed to be in good condition with no structural defects apparent. The framed portion of the ground floor in the classroom wing, consisting of wood floor joists, diagonal wood plank floor sheathing, was observed to be in good condition where 3

7 accessible. Further investigation of the framed portions of the ground floor is recommended, which was not accessible during the site visits. If the building is to be used for future occupancy, structural repairs will be required as follows: Damage to the exterior terracotta wall. Open joints / cracks in the exterior cast stone trim band. Water damage to the classroom wing wood roof framing. Water damage to the wood 2 nd floor framing. Water damage / cracks to the interior plaster / wood lath on the exterior / interior terracotta / wood-framed walls. The cursory design investigation revealed that the building structure will require repairs / replacements and modifications for upgrading the structure to the current building code (2007 Edition). These upgrades are as follows: Reinforcement to the exterior terracotta wall panels. Reinforcement to all door and window openings (jamb / sills). Connections between the bearing ends of all wood joist / truss and terracotta walls on the roof / floor levels. Additional fasteners to the roof wood planks. In addition, the building will also require architectural and M.E.P. repairs / improvements per the requirements of this current code. All windows / doors / louvers, etc. will also require replacement to comply with the current code. 4

8 GENERAL OBSERVATIONS A. Exterior 1. North Elevation (exhibit 12). a. The painted stucco cladding of the exterior wall was noted to be in good condition with no cracks / deficiencies observed. Flaking / peeling paint is present throughout the entire North exterior elevation. b. The aluminum single-glazed glass windows were in fair / poor condition reflecting the results of age with some broken glazing apparent. c. The louvers above the lower level windows were observed to be in poor condition. d. The two exterior doors of the elevation were noted to be in poor condition. 2. East Elevation containing exit door from the auditorium / gymnasium wing (exhibits 8 11). a. The exterior paint on the stucco cladding was noted to be in poor condition with extensive peeling / flaking of the paint observed. b. The textured stucco cladding was in good condition with no cracking or deterioration observed. c. The cast stone bands / window sills were observed to be in good condition with no defects noted. Roof overflow pipes present on the South section of the elevation. d. The single-glazed glass / aluminum windows were in fair / poor condition due to aging with some glazing missing / boarded-up (exhibits 9, 10). e. The painted metal facia at the auditorium / gymnasium section of the elevation was noted to be in good condition with the exception of some minor damages observed at the Northeast corner. f. Doors and some lower level windows at the North end of the elevation were boarded up. The protective boarding was observed to be deteriorating. g. Damage to the stucco cladding and terracotta block wall was observed at the Southeast corner of the elevation. We were advised that his damage may have been the result of a lightning strike some time ago (exhibit 7). 3. South Elevation building front containing the building entrances (West and East) (exhibits 1 6). 5

9 a. The painted stucco cladding on the exterior terracotta masonry walls was observed to be in good condition with a few minor stucco cracks apparent. The painting in some areas was observed to be flaking / peeling. b. The aluminum / single-glazed glass windows were observed to be in fair to poor condition with the results of aging evident. c. The cast stone trim at the window sills and the arch window columns was observed to be in good condition with no structural defects apparent. d. The East and West entrances with the stucco clad columns and cast stone trim were noted to be in good to fair condition with some minor cracking observed. The exterior jambs (exhibit 5) were in poor condition, deteriorated / rotted. Entry doors were in poor condition and partially boarded up. e. The concrete entry platforms / steps were noted to be in fair condition, worn from aging, with no structural cracks / defects observed. 4. West Elevation containing the exit from the auditorium / gymnasium wing (exhibits 13 19). a. The stucco cladding on the exterior terracotta masonry walls of this elevation was observed to be in good overall condition with some minor cracking noted in a few isolated areas (exhibits 13, 15, 16). The painted surface was noted to be peeling / flaking in many areas throughout the entire West elevation. b. The cast stone trim band, cast stone sills and column trim at the arch window areas of the elevation were observed to be in fair condition with some opening of the joints noted (exhibits 14, 15). c. The wood-framed / single-glazed windows observed in the arch window area (North section of the elevation) were observed to be in poor condition. The aluminum frame single-glazed arched windows occurring at the South portion of the elevation were noted to be in fair condition (exhibit 17). d. The aluminum frame / single-glazed windows throughout the remaining overall West elevation were observed to be in poor condition, many with boarded-up glazed panes (exhibit 13). e. The exit doors observed on this elevation were in poor condition with signs of age and deterioration (exhibit 13). 5. Roof investigation of the roof cladding is not included in this report. 6

10 B. Interior 1. Roof Framing a. Auditorium / gymnasium wing (exhibits 24, 30, 32, 33): The structural roof framing system, consisting of riveted steel bow -type long span trusses, heavy timber purlins and wood plank decking, was observed to be in good condition with no structural defects apparent. Structural steel I beams with wood rafters and wood decking were observed to be in good condition with no visual structural defects noted and are present over the stage area of the auditorium / gymnasium. b. Classroom wing (exhibits 29, 34 39): The roof framing structural system, consisting of wood roof rafters stick framed wood trusses and wood plank roof decking, observed to be in good condition with no structural deficiencies apparent, albeit, in the observed isolated areas of severe water / moisture damage and long-term deterioration (exhibit 29). 2. Second Floor Framing (exhibits 22, 27): The structural framing system of the second floor classroom wing, consisting of wood floor beams, diagonal wood plank floor decking and finished hardwood tongue and groove flooring, observed to be in generally good structural condition with no apparent structural defects observed, except in the few isolated areas of severe long-term water / moisture damage (exhibit 40). It is to be noted that additional areas of damage to the finished hardwood flooring were noted in numerous areas of the classroom wing. 3. Ground Floor Framing (exhibits 20, 21): The ground floor framed area under the auditorium / gymnasium floor, consisting of a reinforced concrete slab / joist system with reinforced concrete beams and columns, was noted to be in good condition with no structural defects observed. The ground floor framing system located under a portion of the classroom wing, consisting of wood floor joists, diagonal wood plank decking with finished hardwood tongue and groove flooring, was observed in limited areas to be in good condition with no structural defects apparent (exhibit 20). 4. Exterior / Interior Bearing Walls (exhibits 25, 26, 31, 35, 36). a. The exterior bearing walls of the building consist of cement plaster, wood lath on stucco clad terracotta clay masonry units in running bond. The condition of the terracotta masonry units was observed to be in good condition with no structural deficiencies apparent. The interior plaster was observed to be cracked and moisture damaged. Wood lath was observed to be in fair to good condition, except in areas of moisture damage. 7

11 b. The interior bearing walls (exhibits 25, 37, 39), consisting of cement plaster, wood lath on terracotta clay masonry units or cement plaster on wood lath and wood stud partitions, were noted to be in good overall condition with some areas of isolated damage observed. Water / moisture damage was observed on the plaster surfaces in various areas throughout the building. 5. Foundation A review of the original construction documents indicates that the foundation of the building consists of a 4 reinforced concrete slab-on-grade, reinforced concrete walls, continuous footings and spread footings. Field observations of the foundation system were not performed due to being inaccessible. 8

12 FEASIBILITY STUDY A. Codes and Standards Florida Building Code, 2007 Edition with 2009 Supplements Design wind speed is 140 mph, exposure C, Importance Factor is 1.15 Existing Reinforcing Steel Fy = 18 ksi Structural Steel Fy = 24 ksi B. Design Loads Wind loads per ASCE 7-05 Roof live loads 20 PSF Floor live loads 50 PSF classrooms, 100 PSF corridors, 80 PSF auditorium / gymnasium. C. Foundation System 1. The original drawings indicate that the foundation system consists of isolated and continuous spread footings. 2. The existing footings were not accessible in the field of our review. The original drawings do indicate footing sizes and rebar. The isolated spread footings for the interior columns with rebar are shown in footing schedule. 3. No information on the allowable soil bearing pressure was indicated on the contract drawings available for our review. For our preliminary analysis, we are using 3,000 PSF as a safe soil bearing pressure. Our design analysis indicated that the existing isolated spread footing is structurally adequate to support the required gravity loads. 4. The existing continuous footings at the interior demising walls and exterior building perimeter walls are specified on the original drawings. The perimeter walls and some interior walls will be utilized as shearwalls (to resist hurricane wind loads per the current code). 5. These footings are sufficient to resist the gravity / hurricane wind loads per the current code. D. Wall Framing System 1. Exterior: a. Ground Floor Description: 12 stucco clad terracotta block unreinforced walls present on all elevations. 9

13 Comments: a.1: 12 terracotta block masonry unreinforced wall panels are not adequate to resist the present Florida Building Code wind loads. a.2: The walls are adequate to support the proposed superimposed gravity loads. a.3 The existing windows / doors / jambs / sills are in poor condition, not adequate to resist current Florida Building Code wind loads. Repairs: a.1 See repair details, Exterior Wall Reinforcement. a.2: None. a.3: Remove and replace with new doors / windows conforming to the present Florida Wind Code. In addition, the window / door jambs, head and sills must be reinforced to properly support the windows / doors (see Typical Window / Door Reinforcement Detail). b. Second Floor Description: 8 stucco clad terracotta block unreinforced walls present on all elevations. Comments: b.1: 8 terracotta block unreinforced wall panels are not adequate to resist the present Florida Building Code wind loads. b.2: The walls are adequate to support the proposed superimposed gravity loads. b.3: The existing windows / doors / jambs / sills are in poor condition, not adequate to resist current Florida Building Code wind loads. Repairs: b.1: See repair details, Exterior Wall Reinforcement. b.2: None. b.3: Remove and replace with new doors / windows conforming to the present Florida Wind Code. In addition, the window / door jambs, head and sills must be reinforced to properly support the windows / doors (see Typical Window / Door Reinforcement Detail). 2. Interior (Bearing Walls) Ground Floor & Second Floor: Description: 8 plaster clad terracotta block unreinforced walls. Comments: 1: 8 plaster clad terracotta masonry walls are adequate to resist gravity loads. 10

14 2: Wood joists have no connection to the exterior / interior terracotta walls for proper floor diaphragm and lateral bracing. Repair: 1. None. 2. See repair details Typical Hurricane Tie-Down Details. E. Floor Framing System 1. Ground / Second Floor Classroom Wing Description: 3 x12 / 2 x12 wood floor joists at 16 on center with 1 x6 diagonal wood plank decking. Comments: The existing 3 x12 / 2 x12 wood floor joists at 16 on center with 1 x6 diagonal wood plank decking is sufficient for the present gravity loading in the areas where there is no damage. Wood joists have no connection to the exterior / interior terracotta walls for proper floor diaphragm and lateral bracing Repair: All floor-framing in areas of damage are to be repaired as shown / noted in the floor joist repair details (see Wood Framing Repair Detail ). For joist bearing connections, see Typical Hurricane Tie- Down Details. 2. Second Floor Auditorium / Gymnasium Wing Description: Reinforced concrete / joist system with reinforced concrete beams / columns. Drawings do not indicate any reinforcing. Comments: Auditorium / gymnasium wing floor framing system is sufficient to support the present gravity loading using minimum reinforcing steel requirement. Repair: See Typical Concrete Repair Details for repair of minor spalls, cracks, exposed rebar. F. Roof Framing System 1. Classroom Wing Description: 3 x12 / 2 x12 wood rafters at 16 on center with 1 x6 wood plank decking and 2 x8 stick wood trusses at 16 on center with 1 x6 wood plank decking. Comments: The roof framing is sufficient to support the present gravity loads. Tie downs / straps for resisting wind uplift / lateral loads are not present. The 1 x6 wood planks will also require additional fasteners to resist wind uplift loads. 11

15 Repairs: Hurricane wind tie-down straps / tie-downs are required to resist the uplift / lateral wind loads of the present Florida Building Code (see Typical Hurricane Tie-Down Details ). 2. Auditorium / Gymnasium Wing Description: Structural steel riveted bow trusses, heavy timber roof purlins, with wood plank decking. Steel I beams with wood rafters and wood plank decking over the stage area. Design information was not found on the roof steel / wood framing over the stage area; this area was also inaccessible. Comments: Auditorium / gymnasium roof framing is sufficient to support the present gravity loading. No tie-downs /straps to resist wind uplift loading are present. Repairs: Hurricane wind tie-down straps are required to resist the uplift wind loads of the present Florida Building Code (see Hurricane Tie- Down Details ). 12

16 GENERAL NOTES The information is this report is based on information transmitted by your office. We were commissioned to make a limited visual review of the structure and provide general methods of repair. This report is based upon clearly, visible, open and unobstructed areas of the premises on the date of our site visits. No opinion is rendered with regard to structural elements, which are concealed. Our report attempts to establish the areas and the amount of repair that is necessary. This limited review does not guarantee the structural integrity of the premises under its current use nor any proposed alterations. If you have any questions, please feel free to contact our office. O DONNELL, NACCARATO, MIGNOGNA & JACKSON, INC. Joseph F. Mincuzzi, P.E. Vice President John W. Dawson, BSCE Project Manager STATE OF FLORIDA Registered Professional Engineer No Registered Professional Special Inspector No Registered Building Inspector No. BN

17 PHOTOGRAPHS Exhibit 1 Exhibit 2

18 Exhibit 3 Exhibit 4

19 Exhibit 5 Exhibit 6

20 Exhibit 7 Exhibit 8

21 Exhibit 9 Exhibit 10

22 Exhibit 11 Exhibit 12

23 Exhibit 13 Exhibit 14

24 Exhibit 15 Exhibit 16

25 Exhibit 17 Exhibit 18

26 Exhibit 19 Exhibit 20

27 Exhibit 21 Exhibit 22

28 Exhibit 23 Exhibit 24

29 Exhibit 25 Exhibit 26

30 Exhibit 27 Exhibit 28

31 Exhibit 29 Exhibit 30

32 Exhibit 31 Exhibit 32

33 Exhibit 33 Exhibit 34

34 Exhibit 35 Exhibit 36

35 Exhibit 37 Exhibit 38

36 Exhibit 39 Exhibit 40

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