Washington Christian

Academy

Flagship & Gymnasium

Olney, MD

Casey Mowery Construction Management Option

Building Stastics -- Part I

General Building Data

• Building Name:  Washington Christian Academy Flagship Building & Gymnasium

• Location:  16227 Batchellors Forest Road, Olney, MD 20832 (Montgomery County)

• Building Occupant Name:  Washington Christian Academy (WCA)

• Function:  Educational facility intended for students in K-12 & WCA administration offices

• Size:

• Flagship School – 67,594 SF
• Gymnasium – 10,655 SF
• Total: 78,249 SF

• Stories:          

• Flagship School – 3 stories
• Gymnasium – 1 story

• Project Team:

• Owner
• Washington Christian Academy -- www.washingtonchristian.org

• Architect
• Grimm + Parker Architects -- www.grimmandparker.com

• Construction Manager / Design-Builder
• Forrester Construction Company -- www.forresterconstruction.com

• Civil Engineer
• Rodgers Consulting, Inc. -- www.rodgers.com
  

• Structural Engineer
• Columbia Engineering, Inc. -- www.columbiaengineering.com

• Mechanical and Electrical Engineer
• L.S. Grim Consulting Engineers -- www.lsgrim.com

• Dates of Construction:  January, 2007 – August, 2008

• Cost: 

• Flagship Cost / SF: $164.03
• Gym Cost / SF: $148.23
• Approx. Total Estimated Cost (including Site, Flagship, and Gym): $20.7 Million 

• Project Delivery Method:  Design-Build

• Architecture

  The Washington Christian Academy (WCA) Flagship School and Gymnasium reside on 60 acres in Olney, Maryland.  These two buildings make up Phase I of design and construction.  Eventually, the 60 acre WCA site will become a resting place for an entire educational and recreational campus.  The campus will include the Flagship building, gymnasium, outdoor athletic fields, upper and middle schools, performing arts space, and staff housing. 

  The flagship building includes 35 classrooms, a library, gallery and great hall, and dining/performance space. Additionally, the Flagship building will house the WCA administration offices, which currently reside in Silver Spring, MD.

  The general architecture is classical with a brick façade.  There are three prominent towers with peaked gable roofs along the front of the building, which serve as focal points of the architecture.  These peaks are symbolic of historic tradition, something the WCA prides itself on.  Each tower contains a large aluminum and glass storefront window with cast stone lintels.

  

  The brick pattern on the towers is made up of assorted bricks that protrude 1/2" from the face brick. A brick entry archway greets visitors with a cast stone decorative medallion above the door. The gymnasium showcases similar architecture, thus creating a unified campus aesthetic.

   

• Applicable Codes

• International Building Code 2003 (IBC)
• NFPA 101 Life Safety Code 1997

• Zoning and Historical Information:

• Washington Christian Academy History

The original school was founded in 1960 by families from Presbyterian and Christian churches.  It was founded on the principle of Reformed Tradition, which is based on welcoming a diverse student population (racially, socially, and any Christian denomination).  In 1996, the school merged with Silver Spring Christian Academy and henceforth was named Washington Christian Academy.  The new Flagship school will serve approximately 300 K-12 students.

• Zoning

  The WCA campus will eventually cover a 60 acre site.  Of the 60 acre site, approximately 26 acres are reserved for forest retention.  This land was bought by WCA in 2004. The Flagship's construction classification for the building use is E -Educational and A2 -Assembly. The Gymnasium's construction classification is A3 -Assembly.

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• Building Envelope:

The building envelope utilizes a standard cavity wall system. The flagship building uses an 8" CMU load bearing back up wall, and the Gymnasium uses a 12" CMU wall. To the exterior of the CMU walls are 2 inches of rigid insulation and then a 2 inch air gap. Cavity Drainage Material and Through Wall Flashing are located within the cavity wall near ground level, which allows the moisture to escape. To the exterior of the cavity wall system is a brick facade, also referred to as face brick. A standard modular size brick in two colors is used, as well as bands of 8" split face CMU. 8" accent brick patterns project 1/2" from the face brick on all of the 3-story peaked tower elevations as well as on the gymnasium exterior walls. Three large arched storefront windows are located on both the Flagship building and the Gymnasium. There is one window on each of the 3 towers of the Flagship, and 3 on the NE face of the Gymnasium. These windows are aluminum and glass, with cast stone lintels.

Similar roofing systems are used on the two buildings. Both roofs support the mechanical units for the building. The roof system is a Built-Up Roof. The roof is formed by steel roof deck, followed by 3" rigid insulation, 1" cover board, and built-up asphalt roofing. There is a multiple-ply membrane base flashing that extends a minimum of 8" up the parapet wall for moisture protection. The parapet wall is comprised of 100% solid CMU, covered by continuous Through Wall Flashing and a Cavity Drainage Material. Weep holes are located every 16" O.C. Metal gutters and downspouts are used on the perimeter of the roof.

Both buildings also employ asphalt shingled gabled roofs with a 12:12 pitch. The Gymnaisum uses this roof type over the entry canopy. The Flagship building uses this roof on the 3 peaked towers and the entrance of the building. Additionally, a smaller shed-like shingled roof runs along the roof's perimeter of the Flagship building. This aesthetic barrier will add a sense of completeness to the building, as well as hide the roof mechanical units. The familiar, family-style roof coincides with the architectural feel of the campus and exemplifies the WCA theme of tradition.

 

Building Stastics -- Part II

Primary Engineering Systems

Many of the same design and construction elements are used in the Flagship and Gymnasium Buildings.  This is to alleviate an added learning curve, make construction more efficient, and create buildings that look similar. 

• Excavation (Early Construction)

The excavation for the foundation was simple in nature due to the shallowness of the foundation system.  The foundation is comprised of continuous concrete wall footings and a slab on grade.  Most of the excavation work had to do with removing the upper 1-2 feet of the top layer of soil and recompacting for bearing strength under the slab on grade.  The soils from the onsite cuts are acceptable to use as compacted backfill, as long as they are aerated and dried a bit.  The excavated soils have moisture contents above what is needed for optimum compaction levels.  In order to handle the excess water, man made storm water management ponds around the site collect most of the site drainage.  They are bordered by silt fences to ensure that they do not get overfilled or clogged with silt and other fine particles.  Additionally, there is a pump for dewatering during construction.  A stream that runs near the entrance of the site has been temporarily diverted for the construction of an entrance bridge, and will be returned to its original location upon bridge completion.  Any remaining ground water is pumped through hoses into one of the storm water management ponds so that the water does not cause erosion and further problems during construction.

• Structural Systems
  
  Overview
  Cast-in-place concrete, CMU load bearing block walls, and steel joists comprise the foundation and superstructure of the building.  There are also steel tube columns that are supported by cast-in-place concrete piers and footings in the areas of the building where the span from each load bearing wall is too great. 

Cast-in-Place Concrete
The cast-in-place concrete foundation is the same for both buildings.  The continuous wall footings range in size from 2’-6” to 4’-0” and in thickness from 1’-0” to 1’-4”.  They are typically reinforced with #5 or #7 rebar running in both directions along the bottom of the footing.  Turned down slabs are also employed in the foundation of the Flagship Building.  The depth of this part of the foundation is intended to surpass the freeze-thaw line.  Also unique to the Flagship Building are concrete footings and piers in the center of the building to support steel tube columns.  The cast-in-place pier footings range from 5’ square to 8’-6” square, and support 20”x20” concrete piers with 4-#8 reinforcing bars.  The slab on grade (SOG) requires the bearing soil to have a minimum compaction strength of 2500 psf.  On top of the compacted soil is 4” of washed gravel and a 6 mil. vapor barrier.  The SOG is 5” thick.  The cast-in-place concrete slabs for the second and third floors are 3” thick.  All slabs in the building are reinforced with 6”x6” W1.4xW1.4 Welded Wire Fabric for reinforcing.  The required strength of the concrete is 3000 psi normal weight at 28 days, with the extra stipulation of 4500 psi normal weight if the concrete will be exposed to weather while curing.  The preferred method of placing concrete on the site is by a concrete pump.  The pump can easily reach the third floor slab, and can reach the entire floor with a minimal amount of truck movement.  Keyed construction joints allow for multiple concrete placements.

CMU Block & Steel
The Flagship Building uses 8” CMU and the Gymnasium uses 12” CMU block for the load bearing walls.  The reinforcing in these walls is spaced every 24” on center.  For non-load bearing walls, the only difference is that the reinforcement spaces out to 48” on center.  The CMU minimum compression strength is 1900 psi.  The steel used in both buildings acts as a load bearing system that spans the distance between load bearing walls.  The steel is in the standard forms of beams, joists, and trusses.  The ends of the steel beams bear on an average size steel plate of 8”x12”x5/8”.  Joists that bear on masonry walls are supported by a steel plate and a bond beam.  There are 13 steel tube columns in the Flagship Building, which allow for large, open architectural spaces.  The large spaces would not be possible with CMU load bearing walls alone because the span distance would be too great.  The typical column is a HSS 8”x8”x ½”.  Anchor bolts with a ¾” diameter connect the columns to a steel base plate that sits on top of the cast-in-place concrete pier mentioned previously.  The steel is set in place by a mobile crane that will move through three locations for the Flagship Building and one location for the Gymnasium.

• Mechanical System

Once the buildings’ structures are complete, the mechanical and electrical systems are ready to be put in place.  The Flagship Building has an adjoining mechanical and electrical room in the northwest section of the building.  There is also a small electrical closet located in the main corridor of every floor.  16 mechanical rooftop units serve the entire building and are typically 480V, 3phase.  These units are hidden from a pedestrian line of sight by a shed-like gabled roof that runs along the perimeter of the built up roof.  This aesthetic barrier adds a sense of completeness to the building, as well as hides the roof mechanical units.  Roof top metal ventilators, bases, and soil stacks are kept watertight by metal flashing and roof sheathing.  The kitchen on the main floor of the building requires additional mechanical equipment that would not typically be seen in every building.  Compressors and condensing units for the kitchen are located on the roof in addition to 2 exhaust fans.  The exhaust fans are rated at 600 and 3250 cfm and are equipped to exhaust very high temperature air reaching up to 300 degrees F with no damage to the fans. 

The supply air is distributed throughout the Flagship Building by VAV fan powered terminal units with electric heat.  The size of the units range from 720 to 1350 max cfm.  Most of these VAV units serve 4 or 5 air supply diffusers.  Typically, one unit is located above each room for occupant temperature control and comfort.  The VAV units are connected to each diffuser with a removable flex duct.  Larger open spaces, such as the corridors, are equipped with VAV single duct terminal units with electric heat that range in capacity from 300 to 1025 cfm.  Typical registers and grilles collect the return air.  All of the ductwork is to be insulated sheet metal and sealed with a mastic sealer.  Any duct interiors that are visible through a grille or register are to be spray painted mat black to avoid an unfinished metal aesthetic look.

The Gymnasium’s mechanical system is similar, only with less ductwork and stronger powered air handling units.  There are two roof top units.  The first unit has a capacity of 1600 cfm, which serves the lobby, locker rooms, restrooms, and offices.  The second unit has a much larger capacity of 6000 cfm and serves the entire gymnasium.  Both units are 480V, 3 phase.  There is a small mechanical room located in the gym.

• Electrical/Lighting Systems

The electricity is supplied to the Flagship Building through a switchgear located on the other side of Batchellors Forest Road from the school.  The 15kV switchgear connects by way of a one-way duct bank to an electrical manhole.  This manhole is then connected by a one-way duct bank to a pad mounted 480V Delta Primary – 208Y/120V Secondary 3 phase transformer which is located directly outside the south end of the Flagship Building.  Once inside the building, the main power distribution panel is 480Y/277V 3 phase, 4 wire, 1600A, and 100% rated.  All conductors are copper with type THW 75C insulation.  The current AV equipment is connected to a junction box embedded in the slab by a 3” diameter conduit.  To account for future demand, an extra 3” diameter conduit is attached to a junction box in the ceiling above the AV room for future equipment hookup.  Electrical receptacles are mounted on the roof for servicing mechanical equipment. 

The lighting in the Flagship Building hallways and classrooms are rectangular fluorescent luminaires.  The foyer, also referred to as the Great Hall, has incandescent ceiling and wall mounted fixtures.  Some indirect wall pendants are used in this space to create a certain aesthetically pleasing atmosphere.

The Gymnasium gains its electricity from the main Flagship Building electrical room.  Two 4” diameter PVC conduits run underground from the electrical room to the Gymnasium.  Fluorescent lighting is used in the lobby, offices, and locker rooms. In the gym, HID light fixtures are ceiling mounted for efficiency.  There are 2 main electrical panels for the building, which serve the same areas as the mechanical units. 

• Emergency System

The fire and emergency systems for the two buildings are the same.  The fire alarm control panel is located in the first floor main electrical room of the Flagship Building.  Annunciator panels are located next to the front doors of each building.  The Great Hall has addressable smoke detectors, and the rest of the building and gym has dual audio/visual smoke detectors.  In any HVAC over 2000 cfm each, or any HVAC serving a common plenum space exceeding 2000 cfm in that plenum, a smoke detector is required.  The emergency lighting is unique because it is self-testing.  Self-testing bodine ballasts and circuitry will automatically test emergency lights for 30 seconds every 30 days and 90 minutes per year.  The sprinkler systems in both buildings are a standard wet sprinkler with cast iron pipe and steel fittings.  The sprinkler heads are semi-recessed pendant type with chrome painted finish. 

 

 

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