Daniel Zartman's Capstone Project

Structural System
The primary structural building material for the CSL is structural steel. Beam sizes consist primarily of types W12 and W16 made of ASTM A992 steel with a yield strength of 50 ksi. Column sizes consist primarily of HSS 4x4 and HSS 6x6 shapes made with ASTM A500 Grade B with a yield strength of 36 ksi. The CSL is unique in that it is being constructed against a steeply sloped hill. The building’s structural system benefits from this design in that it requires little lateral bracing. Lateral loads that are imposed on the frame are channeled back into the concrete foundation/retaining wall (highlighted in red on Figure 1) that extends to the bottom of the 3rd story and span across 4 of the 8 structural bays in the building. The crane used for the erection of steel was a Terex Model T560, a 50 ton hydraulic truck crane. The cranes location changed with the progression of construction; moving from the western portion of the site to the eastern portion.

Figure 1 - Highlighted in red is the concrete foundation/retaining wall that provides lateral support.

Cast-in-place (CIP) concrete was utilized as a secondary structural component on numerous aspects of the project. Specifically, cast-in-place concrete was used as for foundation footings and walls, a column in the atrium, the atrium stair, Slab on Grade 1st floor, Slab on Deck above grade floors, and a few select concrete walls. Metal reusable wall forms were used for all CIP concrete with the exception of the atrium column and stair; both of which are currently being considered to be constructed out of an alternative material for constructability reasons. Above grade SODs are constructed of 2” composite metal decking with a 3-1/2” concrete slab placed on top of welded wire fabric reinforcing. Due to accessibility reasons, placement of the majority of concrete required the use of a concrete pump. All slabs required the use of Lightweight concrete.

Exterior Wall Assembly –
            The exterior wall assembly design fully embodies the sustainable design motifs of the project. Depicted in Image 6, is a cross section of a portion of a typical exterior wall. 2 types of exterior glazing are used, all of which are Sealed Clear Insulating Glass Units (IGU) with multiple Low-E suspended films. Significant variations include; thicknesses of 1-1/2”, 1-1/4”, and R-Value of 10.87, 7.69 respectively.   

Wall Assembly from Outside Surface to Inside Surface

1. Reclaimed Barn Wood
2. Wood battons
3. Air Space
4. 2” Rigid Board Insulation
5. Weather Barrier
6. 5/8” Glass-Mat Gypsum Sheathing
7. 8” Metal Stud Framing
8. 8” Fiberglass Insulation
9. 5/8” Gypsum Wall Board       

Mechanical System –
Perhaps one of the most technically advanced systems in the CSL, the mechanical system is a combination of passive and active design. The majority of the building is heated and cooled by one variable air volume AHU supplying a maximum of 12,400 CFM. A geothermal ground source heat pump and enthalpy wheel was installed in order to further reduce the energy load imposed by the AHU. Housed on the north side of the first floor, the mechanical room supplies the AHU with preconditioned refrigerant from the closed loop geothermal system and air pressure to the dry pipe fire suppression system. In addition, other unique design features include a raised floor system for the distribution of supply air, thermal radiant floor heating to provide supplementary heat, and a green roof for increased thermal mass to stabilize the heating and cooling loads. Unconditioned space, such as the large atrium, remains entirely heated and cooled naturally through passive design. Figure 2 & 3 depict the air flow in the passively design spaces..

Figures 2 & 3

Electrical System –
Due to the new facilities close proximity to the existing Phipps Conservatory; a 600 amp 3 phase electrical service connects the new CSL with the existing neighboring facilities.  Standard voltages of 120/208 and 277/480 are distributed as needed throughout the building via the raised access floor system.  A unique aspect of the electrical system is the large amount of power generated onsite.  A current goal for the building is to maintain net-zero energy use on an annual basis. Onsite generation is primarily composed of three 36 kW solar panel arrays, but also utilizes vertical axis wind turbines to supplement demand. Furthermore, the utilization of a Direct Digital Control Building Management System will provide system feedback for optimal energy efficiency. Aside from having onsite variable power generation, no redundant electrical systems are being installed.

The lighting system is a hybrid of energy efficient LED, florescent lighting, and natural lighting design. The CSL is equipped with a building automation system that controls the amount of natural light that enters a space through a system of moveable sunshades. The dynamic shading system for this building enables the shades to move over the course of a day and year to control the amount of natural light entering the space. The dynamic shading system also maximizes or minimizes the thermal gains when appropriate to reduce the cooling and heating loads.

Excavation Support System –
In order to properly protect the adjacent Phipps Conservatory greenhouses and to stabilize excavation, the utilization of a rock tieback system was used on the north side of the building. During construction, the internal support from the tiebacks will provide construction workers with a clear space to operate.  Once complete, the tieback system will remain in place as a permanent component of the building structure. For this project, no dewatering system was required.

Project Delivery System –

The CSL was delivered via traditional design-bid-build approach. This approach was chosen because it is a well known project delivery system amongst local contractors. Furthermore, utilizing a design-bid-build delivery system allowed the owner to lock-in a price, prior to the start of construction (making an exception to change orders). The contractor was selected for this project through a private bid proposal.  The contractor, having worked with the owner in the past, utilized knowledge gained from past experiences to their advantage. For the bid, a Bid Bond of 5% of the contracted value was required. The successful bidder was also required to furnish both a Performance Bond and Payment Bond for 100% of the contracted amount upon award.