Executive Summary. Proposal. 12/5/2002 Consultant: Dr. Boothby

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1 Executive Summary The following paper is a proposal for further thesis research into the design of the Brunswick School Athletic Building. This building is split into three major sections: an ice hockey rink, a basketball court and a three-story central brain which houses a weight room, locker rooms, offices and squash courts. The design and construction teams included Skidmore, Owings & Merrill (SOM), Gilsanz Murray Steficek (GMS) and Turner Construction and was completed in late summer The design was developed to resemble the shaker-style barns and houses of Connecticut. All proposed redesign will aim to retain this style of architecture. The existing structure consists of fully-grouted CMU walls with 105 spanning glulam timber trusses, by Unadilla Laminated Products, spaced at bearing on concrete piers within the walls. The trusses have a steel bottom chord to aid in carrying tension loads. In the brain section, the floor system consists of pre-cast concrete planks on loadbearing masonry walls. The roofing system is made up of asphalt shingles on cedar plywood and rigid foam insulation bearing on purlins framed into the trusses. The CMU walls are covered with cedar siding on cedar plywood and rigid insulation or stone over rigid insulation. The building foundation consists of large concrete footings under each pier as well as a footing at the base of all walls. Reviewing the design of many other long span roofs over swimming pools, ice rinks or similar spaces revealed that a arched frame is often used to support the roof and the walls. A rigid frame design would allow the roof framing to be finished earlier in the building construction, rather than waiting for the walls to be finished. Piers would no longer be needed within the walls. The proposed thesis will contain analysis of a glulam timber arched frame, retaining the barn feel of the building. The frame should be two pieces joined at the top peak. Unadilla is a frequent designer, manufacturer and supplier of such frames. The American Institute of Timber Construction specifies sizes of frames similar to the one to be analyzed in design charts. Wind, seismic, snow and dead loads will be applied to the proposed frame to refine dimensions. Based on new dead loads with timber frames rather than timber trusses and concrete piers, foundation sizes will be reviewed. Detailed changes in costs will be analyzed and compared to costs of the existing structure. In addition to research into structural revisions, the proposed thesis will review the performance of the building envelope. The quality of the walls resistance to heat flow, water vapor flow, water penetration, CMU shrinkage and thermal expansion will be investigated. Thermal and vapor gradients will be developed, and locations of expansion

2 joints, moisture barriers, insulation and flashing will be reviewed. Interior conditions in both the ice rink and basketball court will be countered with exterior summer and winter conditions for Greenwich, Connecticut. Interior conditions will be determined by visiting local buildings with similar environments, while exterior conditions can be found at numerous weather websites. Material performance values for thermal expansion, heat flow resistance and vapor resistance will be gathered from ASHRAE Fundamentals. In the proposed thesis, lighting conditions in the ice rink will be researched. The present light fixtures induce bright spots of concentrated light on the ice surface; such spots can distract players causing dangerous playing conditions. New fixtures that supply indirect light will be selected so the bright spots not occur. The new fixtures need also to accommodate the absence of a bottom truss chord with the new structural framing. A detailed calendar of the proposed research is included with the following report. The structural analysis will take significant time, as will envelope research. Light fixture selection should take minimal time given the vast resources available online.

3 Building Background The Brunswick School Athletic Building was built as part of Phase I of the newly opened Edwards Middle School Campus of the boys college preparatory school in Greenwich, Connecticut. The winter sports complex was completed in time for the Fall 2001 semester, and cost roughly $11 million to build. The entire Phase I project, including an academic building and site work for the 104 acre campus, was designed by Skidmore, Owings & Merrill, LLP, New York, NY. The structural engineers on the project were Gilsanz Murray Steficek, LLP, also of New York. Construction was managed by Turner Construction Company. The roof trusses were designed and built by Unadilla Laminated Products, Unadilla, NY. The ice hockey rink was design-build contracted to American Refrigeration Company, Inc. from Woburn, MA. The 65,500 square foot facility houses an NCAA regulation-size ice hockey rink, an NCAA regulation-size basketball court, 8 international size squash courts, a weight room, locker rooms, and offices. The building is divided into three major sections: the rink, the brain and the court. The location of these sections can be seen in Figure 1, the first floor plan. The rink and court have 24 foot high walls and 105 foot roof span, as shown section in Figure 2. The brain between them is three stories, visible in section in Figure 3, is where the locker rooms, squash courts and offices are located. The overall design of the building was selected to reflect the shaker-style Connecticut architecture of local barns and houses. Figure 1: First floor plan; rink, brain and court labeled left to right

4 Figure 2: Building section through rink; shows truss shape Figure 3: Building section through brain

5 All exterior walls to the athletic building are fully grouted concrete masonry. The south wall of the ice rink is 10 block with minimum rebar, and all other walls are 12 block with minimum rebar. Horizontal reinforcement consists of 2-#9 bars at 16. Any parts of walls located below grade, such as the first 8-10 feet of the rink s south wall, are cast-in-place concrete retaining wall. The walls are interrupted by solid 36 x 16 (36 x 14 on 10 block walls) concrete piers spaced Control joints in the masonry walls are located at each set-back corner, as shown in Figure 4, and at each pier. The walls and piers are fully braced at their base by dowels poured with the footings. The footings under each pier are as large as 7 x 7. All footings are anchored into very rigid soil. The concrete block is covered with rigid insulation, cedar plywood and cedar siding, or rigid insulation and stone, also visible in Figure 4. All CMU walls are left exposed in the interior spaces. Walls within the center brain of the building are load-bearing fully-grouted 8, 10 or 12 block. The third floor, the mechanical mezzanine, consists of 4 concrete on metal deck, supported by wide-flange steel beans spanning These beams rest on W12 and TS12 Figure 4: Detail at corner, shows expansion joint and exterior wall materials columns that pass down to CMU walls on the first floor. The second floor is built of hollow pre-cast concrete planks of various thicknesses, bearing into CMU walls and wide-flange beams spanning any doorways or other openings. The first floor of the entire building is slab-on grade concrete. Floor surfaces are unique to each space: insulation, additional concrete and two layers of pipe for the ice surface; carpet in offices; tile in locker rooms; and a sports surface floor for basketball. The roof of the Brunswick School Athletic Building is constructed of glulam timber trusses with glulam purlins, cedar plywood and asphalt shingles. Over the rink and basketball court, the clear span of the trusses is approximately 105 and are spaced apart, bearing into the concrete piers within the block walls. The top chords of a representative truss is 8 ½ x 33 ; the bottom chord is 6 ¾ x 30 ¼ glulam spliced with a

6 steel cable for the middle 1/3 of the chord to resist the high tension forces. The building section in Figure 2 shows the shape of the truss. Also visible in those building sections are the decorative cupolas and dormer windows on the roofs of the rink and court. According to UBC 2000, buildings in Greenwich, Connecticut should be designed for 30 psf of snow and 80 mph winds. For wind and seismic calculations, this building has an importance factor of because it is considered an education facility. The building is located in seismic zone 2A. All steel complies with ASTM A572 Grade 50 (f y = 50 ksi). All masonry has a maximum compressive strength of 2000 psi; mortar is type S; masonry reinforcement is Grade 60. All cast-in-place concrete was specified to be 4000 psi, normal weight, with Grade 60 reinforcing bar. Recessed fluorescent lights hang above most spaces in the facility. 400 watt Prismaline fixtures are suspended in clusters of two above the basketball court and in clusters of four above the hockey rink. These fixtures, as well as those above the squash courts, are covered with guards to prevent damage from balls and pucks. The athletic building is protected from fire damage by an extensive sprinkler system in accordance with the NFPA and Connecticut Building Code. Dry sprinkler systems are used in any building areas subject to freezing temperatures, such as above the ice hockey surface and the adjoining ice and zamboni maintenance rooms. Wet systems are used to protect all other spaces. As with light fixtures, the sprinkler heads above the hockey rink, squash courts and basketball court are covered with protective guards to defend against flying pucks and balls. The large timber trusses do not need fireproofing because of timber s ability to last in fire. Once the wood is charred, the flames cannot penetrate further, allowing large timbers to last longer than steel framing and retain most of their strength longer. The steel cables in the truss bottom chords are not coated with fireproofing.

7 Statement of the Problem A new roofing system will be designed for the ice rink to span 105 feet in place of the existing trusses. Several potential alternatives were reviewed in a prior report; they include a steel bar joist system, steel trusses, steel rigid frame arches and glulam timber rigid frame arches. A system is desired that has the potential to shorten construction time, yet retain the barn-like architectural style of the building. Dead loads will be reduced from those resisted by the existing trusses because the proposed thesis will not keep the long dormer windows because they case unsightly light patterns on the ice surface, shown in Figure 5. Figure 5: Ice rink; Piers marked with BLUE arrows; light from dormers marked with YELLOW arrows; bright spots from light fixtures shown with RED arrows;

8 Proposed Solution to the Problem Reviews of Unadilla Laminated Products website, and the American Institute of Timber Construction s website, spurred the initial review of a glulam rigid frame system. The AITC refers to such frames as Tudor arches. Many buildings housing ice rinks, gymnasiums, swimming pools and other similarly large spaces have roofs framed with glulam timber framing without actual trusses. Examples of this framing system are shown in Figures 6, 7 and 8. The proposed thesis will include refinement of the initial depths shown in Figure 9 that were developed in the second technical report, and widths of 18 ½. By suggestion from the Manager of Technical Services at the AITC, widths will be reduced to 10 ½. Member depth refinement must reflect that Tudor arches are smaller at the peak than they are at the knee. The overall building dimensions, 24 walls, 105 roof spans and 36 roof peak height from floor, will be maintained. The arches will be designed at the same spacing that the existing trusses utilize, rather than the 8 spacing tested in initial designs. Figure 6: Frames over a swimming pool; Figure 7: Animal Science Center, Univ. of Arkansas; Supporting the roof with these arches will allow for removal of the concrete piers that, as shown in Figure 5, do not blend in at all with the CMU walls. Initial design consisted of southern pine, but the proposed thesis will enlist a stronger lumber species, Douglas fir. The preliminary designs eliminated the dormers and cupolas on the roof of the building. The proposed thesis will analyze the possibility of returning the load of the Figure 6: Frames over a basketball court;

9 cupolas at the peak, and refinement of the 75 kip value of a single cupola with a lighter version of the initial design. The frames must be designed to resist the following loads: Dead Loads Roof shingles, sheathing, insulation, 15 psf purlins Service lights & sprinklers (estimated) 15 psf Self weight Douglas Fir included in wood design aids Roof Live per UBC 2000, 1:4.7 slope 20 psf Snow Loads 30 psf Wind Loads Wind from NE & Leeward roof 21.6 psf out SW (into long side) Windward roof 7.2 psf in Top of leeward wall psf in Base of leeward wall psf in Top of windward wall 11.4 psf out Top of leeward wall 10.7 psf out Wind from NW & Leeward roof 19.2 psf in SE (into short side) Windward roof 12.1 psf out Top of leeward wall psf in Base of leeward wall psf in Top of windward wall 11.4 psf out Top of leeward wall 10.7 psf out Seismic Loads Basketball Court kips Hockey Rink kips Brain First floor 52.0 kips Second floor kips Mechanical Mezzanine kips The use of these frames will allow for a shorter overall construction time. This is possible because the roof construction can begin before the CMU walls have begun, rather than after the walls are finished. Interior work can begin much sooner. 5'-6" 5' " 6' " 3' " GLULAM FRAME 3'-8" Figure 7: Preliminary frame sizes from second technical report

10 Solution Method The refinement of the design of the glulam arches will be based on the specifications of the American Institute of Timber Construction in AITC , Standard for Dimensions of Structural Glued Laminated Timber. Design methods are outlined in AITC Technical Notes 2 and 23. The geometry of the arch has already been determined. Based on equations supplied in the Technical Notes, appropriate loads and load combinations will the analyzed. Allowable stresses at critical points will be compared to applied loads. Combined bending and compression loads will be used to determine sufficient sizes at each critical point. Using methods described in Technical Note 2, deflection must be calculated and compared to l/240 per UBC Depth will be increased should deflection be too high. Connections of roof purlins and paneling to the frames will be sized based on the National Design Specifications for Wood Construction, American Forest & Paper Association, Large connections such as where a frame meets a foot will be selected based on member size, tension and shear loads using Wood Construction Connectors, Simpson Strong-Tie Company, Inc., 2002, and similar resources. Masonry ties will be selected to support the masonry walls to the timber frames, as the load-bearing piers will no longer be needed.

11 Tasks and Tools The proposed thesis will be developed based on the following outlined tasks: Task 1) Acquire AITC Technical Notes 2 and 23 a) Based on correspondence as of 12/4/02, the Technical Services Manager at AITC will send design guides by mail b) Should design guides not arrive by start of Spring 03 semester, a copy will be borrowed from the Engineering Library (Call No. TA666.T ) Task 2) Determine loads a) Find spacing based on AITC Technical Notes b) Determine roof loads in pounds or kips per foot c) Determine wall loads on arch in pounds or kips per foot Task 3) Find preliminary member sizes a) In accordance to AITC and Technical Notes determine frame widths up to 10 ½ b) In accordance to AITC and Technical Notes find depths at critical points c) Draw arches tapering from critical points Task 4) Check allowable stresses a) Using Technical Notes, determine allowable stresses at each critical section b) Find appropriate load combination stresses and compare to allowable stresses Task 5) Check deflection a) Check deflection per Technical Note 2 and compare to l/240 per UBC 2000 b) Increase beam depth if needed to keep deflection below l/240 Task 6) Size connections for purlins to framing per NDS Specifications Task 7) Size connections for framing to foundation per Simpson Strong-Tie or similar resources to resist uplift, moment and shear Task 8) Select masonry ties Task 9) Adjust building costs to reflect new building framing and compare to present building costs Task 10) Develop a new schedule showing that construction of the roof and interior spaces can begin earlier in the overall building construction with the new framing system Task 11) Summarize results of design

12 Inter-option In addition to analysis of a new roof framing system the proposed thesis will include research of the Brunswick School Athletic Building s enclosure performance with respect to heat, air and moisture and a revised lighting system for the ice hockey rink space. Enclosure Performance The existing building envelope is comprised to two different systems. The majority of walls in the building are CMU back-up with cedar sheathing and siding with rigid insulation. Some of the walls have the same CMU back-up and insulation, but instead of cedar the façade is stone. Masonry walls are notorious for poor moisture control and thermal performance. The architectural details are often sketchy about location of expansion joints flashing, moisture barriers and weep holes. For this building, expansion joints are assumed to be located at each pier but details have not been found to indicate this. Expansion joint locations are very minimally specified in the drawings. This drawing discrepancy is one of the contributors to masonry façade performance failures. Exterior weather conditions for Greenwich, Connecticut will be gathered from weather data websites. Interior conditions desired for ice rinks, basketball courts and similar spaces will be investigated in ASHRAE references or by visiting local spaces that have similar conditions. Using material thermal and vapor resistances found in ASHRAE Fundamentals, thermal gradients showing the change in temperature over the wall section and vapor gradients showing the change in vapor pressure over the wall section will be developed for winter and summer mean and extreme conditions for each wall suspected of having the potential for problems. If it is determined, by comparing the vapor pressures in the wall to the saturation vapor pressures at each interface s temperature that a wall section may be susceptible to moisture accumulation the wall s ability to discard moisture will be reviewed. Location of moisture and vapor barriers will be analyzed, as well as placement of flashing and weep holes. Should the existing wall sections show room for improvement, a new wall section will be proposed. Wall section details will be developed for the new walls or for the existing sections since present details could be improved. Thermal expansion and CMU shrinkage lengths will be calculated, based on temperature ranges in the thermal gradients, for the masonry walls and compared to expansion joint sizes. Actual construction of the expansion joints will be investigated, as this is also not yet determined from the drawings.

13 Ice Hockey Rink Lighting The existing 400-watt Prismaline fixtures in the ice rink, suspended in clusters of four fixtures, produce bright spots on the ice surface as shown in Figure 5. The proposed thesis will include selection of new fixtures or a new fixture layout to eliminate or reduce these bright spots. Fixture locations may be altered because the truss design will be replaced, and the lights will no longer be suspended from the bottom chords of trusses. The bright strips caused by the dormer windows will be eliminated since these windows will be removed from the proposed building design. Indirect fixtures would have the best capabilities for producing lighting conditions without bright spots. The indirect fixtures cannot utilize reflection onto the building roof, however, because the roof is built of wood. A fixture with its own reflective shield would be ideal for this situation. The same quantity of foot-candles supplied by the existing fixtures must be supplied by the new fixtures or fixture layout. Fixtures will be selected from lighting catalogs in the thesis library or websites such as and

14 Schedule The following pages show a predicted schedule of research and analysis for the proposed thesis. The schedule is subject to change in response to assignments in other courses, early completion of any section of the schedule or delayed completion of any part of the schedule. Summary The proposed thesis will consist of a redesign of the roofing system. The existing timber trusses that span 105 will be replaced by glulam timber arches to be designed by AITC specifications. Use of the arched frames will eliminate the need for the cast-in-place concrete piers and will allow for shorter construction time. Investigations into the building envelope performance and ice rink lighting are also proposed.