Reengineering an Icon

By Carlo Taddei, PE

At an institution steeped in tradition, engineering has been in the DNA of Texas A&M University (TAMU) since opening its doors in 1876 as the Agricultural and Mechanical College of Texas. Combining the tradition of engineering education with two of the university’s core values, excellence and leadership, TAMU seeks to establish itself as the nation’s preeminent institution for engineering research and education and lead the charge in transforming engineering education. The College of Engineering (COE) is now the largest college within the TAMU College Station campus and largest undergraduate engineering program in the nation with 22 engineering majors across 14 departments and over 20,000 students.

According to the President’s Council on Science and Technology, it is estimated that more than one million additional science, technology, engineering, and mathematics (STEM) degrees will be needed in the next decade. The Texas Workforce Commission also projects the need for 62,000 more engineers in the next decade. To address the critical and growing demand for engineers, the TAMU COE launched the 25 By 25 initiative in 2013, which aims to increase enrollment from 14,000 students in 2013 to 25,000 students by 2025. The initiative was designed to enhance the quality of engineering education and shape the engineer of the future by transforming the engineering classroom into a 21st century model focused on technology-enabled learning, hands-on projects, and collaborative, multidisciplinary learning spaces.

As stated by Dr. M. Katherine Banks, Dean of Engineering, “The 25 By 25 initiative is not just about increasing enrollment, but also about providing better instruction and opportunities. We will transform engineering education to mold the engineer of the future.”

The first major step toward this goal was the completion of the Zachry Engineering Education Complex (ZACH) which is focused entirely on undergraduate education. The ZACH stands at 525,000 SF and was achieved by renovating the original 300,000 SF building, adding a vertical expansion onto the building, and adding two, new five-story lateral additions. As a company that employs many graduates of the TAMU Department of Civil Engineering, we were honored to provide structural and civil engineering, and surveying services to TreanorHL Architects on this highly important project.

Reconstruction of Interior Core Including New Learning Stair

Originally opened in 1972, the H.B. Zachry Engineering Center served an enrollment of 15,000 students. The original Zachry building fit the traditional model of 1970s academic facilities: faculty offices, dean’s suite, enclosed research laboratories, tiered classrooms, large lecture halls, and underutilized atrium space. While the building was iconic for engineering students, it lacked energy and failed to provide the multi-disciplinary, interaction, and collaboration spaces that truly enable engineering students to succeed in today’s environment.

As was common in the 1960s and 1970s, the building was designed in the brutalist style of architecture with large monochromatic precast concrete panels covering approximately 75 percent of the building exterior, which many considered to be an eye-sore. The structure did have some cutting edge design techniques and creative solutions, such as the load-bearing precast concrete façade, two-way post-tensioned joist “waffle” slabs, precast concrete double tees for the basement wall, Vierendeel steel trusses across the atrium clerestory, and was designed for vertical expansion. However, the large sloped-floor lecture hall, tiered classrooms, and large atrium posed challenges for reconfiguring to accommodate smaller active learning classrooms and lab space.

The solid interior finishes, compartmentalized interior layout, and precast façade did not provide transparency or foster excitement about engineering. The first question posed to us at the project kick-off meeting was “How are you going to make all of the exterior precast concrete disappear?” It was made abundantly clear to us that the COE did not want to see any of the original precast concrete façade. This created a significant challenge because the precast concrete served as the perimeter support for the concrete superstructure. This set the tone for the project and we quickly realized that the project was going to have some unique challenges that would allow us to showcase our ingenuity and creativity.

The project was broken down into three distinct phases: Deconstruction, Reconstruction, and Expansion.

Completed Active Learning (Seating) Stair and Skyligh. Photo: Randy Braley.

Deconstruction and Site Challenges

The first phase of the project involved issuing a demolition package to cover removal of all building finishes, HVAC services, and major structural demolition. In addition to removing the load-bearing precast concrete panels, structural demolition also involved the large sloped-floor lecture halls, steel Vierendeel trusses at the clerestory, interior stairs, mezzanine structure, and portions of the existing floors and roof.

The precast concrete panels were 10-feet wide C-shaped columns at 16-feet, six inches on-center with a void space in the middle that served as mechanical exhaust. The precast columns were supported by cast-in-place concrete columns between the basement and level 1. To further complicate matters, the existing grade was approximately seven feet above level 1 on the north, east and west sides of the building and the main entrance(s) to the building occurred at level 2. The existing basement wall was located eight feet beyond the building face and consisted of precast concrete double-tees. A structurally spanning concrete sidewalk was present, which braced the basement wall back to the building structure. Where grade extended above level 1, a concrete upturned beam supported the precast columns and structural sidewalk.

The new building program called for the grade to be lowered and entry to the building relocated to level 1 on the east, west and south sides. This required the existing structural sidewalks, basement walls, and upturned beams to be demolished above level 1. Permanent steel shoring was installed to laterally brace the existing basement wall back to the existing building columns during demolition.

In order to remove the precast concrete columns without having to temporarily shore the structure, a new permanent support system was designed consisting of a 16 inch thick cast-in-place concrete basement wall along the north, east and west sides of the building and steel columns to support the floors and roof. The grade along the south side was unchanged, so steel transfer girders were designed to span between existing building columns to support the new steel columns. The steel columns were fabricated with steel “haunches” on the inside face, which permitted the columns to be installed outboard of the floor structure and run full height of the building.

Close coordination with the construction manager was required to ensure work was properly sequenced since columns had to be “fished” down the void space in the precast columns with the steel haunches turned parallel to the floor spandrel. Once the columns reached the bottom, they were rotated 90-degrees to position the haunches below the floor framing. After the steel columns were plumb and the haunches shimmed, the precast columns were demolished from the top down.

Once the precast columns were removed, steel beams were installed between the steel columns around the perimeter of the building at each level, creating a steel “exoskeleton”. Concrete slabs were then installed at each level to extend the floor out to support the new façade, which was outboard of the new steel framing.

As the new focus of the ZACH was aimed at “learning by doing,” the large lecture halls in the original building were replaced with smaller active learning classrooms. This required reconfiguring the center core of the building, including demolition of the large concrete-framed lecture halls. Since the main entrances to the building were reestablished at level 1, a 12,000 SF section of the post-tensioned waffle slab at level 2 was demolished to extend the new central atrium to level 1.

As part of the teaching and research program, the original building housed a 60-year-old, 5W nuclear reactor that had to remain operational during the demolition phase until it could be decommissioned and relocated. This required special detailing and sequencing of demolition to work around the reactor room to avoid disturbance.

Completed Building Southeast Corner Photo: Randy Braley.

Reconstruction

The interior core of the building was reconstructed with structural steel infill framing and a new central “learning stair” between levels 1 and 3 to allow students to study and collaborate. Steel bridges at each level connect the two sides of the atrium and support the stairs. The new infill structure had to be carefully planned and new columns strategically placed to minimize impact on the existing structure. New steel wide-flange columns were “punched” through the post-tensioned waffle slab at level 1 and carried down to the basement. New concrete transfer beams and drilled under-reamed piers were installed to support the new columns.

With the precast façade removed, new limestone cladding and curtainwall was introduced to provide a more transparent and aesthetically appealing structure.

Expansion

Per the original construction documents, the building was designed to accommodate two levels of vertical expansion.  JQ verified this assumption by analysis of the structural framing. To better relate with the five-story building additions on the north and south sides, only a portion of the existing building was vertically expanded. Structural steel was used for the vertical expansion to reduce weight. Approximately half (32,600 SF) of the existing roof was converted into a new fifth floor level and approximately 6,600 SF consisted of a two-story expansion to accommodate a mechanical penthouse.

In order to bring natural light into the building, a new 3,500 SF split-level skylight was designed to run down the spine and span across the central atrium. The 165-foot long skylight begins at the existing roof level (level 5) at the west end, turns vertical up the building face and ends at level 6. The skylight has a tapered design with the west end four feet wide and the east end 42 feet wide. A 2,700 SF section of the existing concrete roof structure had to be removed to accommodate the skylight. The upper skylight support frame consisted of a “tabletop” roof with a center ridge and hipped corners that were rigidly connected for lateral stability. The skylight support elements consisted of hollow structural shapes (HSS).

The two building additions occurred on the north and south ends of the original Zachry building and added 185,000 SF over five levels. The north addition contained a 9,500 SF mechanical penthouse (level 6) even with the vertical expansion over the existing building. The two building additions are cast-in-place concrete superstructures with a wide-module pan joist floor system.

A major challenge for the additions was the location of new columns and foundations in proximity to the existing building. The foundation system for the additions and existing building consisted of under-reamed piers which were large due to the high dead load from the concrete structure. The columns were pulled back approximately 10 feet from the existing building to accommodate large MEP chases to route utilities from the basement level. Even with the offset columns, additional foundation offsets and deep cantilevered strap beams were required to support the columns to avoid conflicts with the existing piers.

To achieve the aesthetic quality and daylighting strategies that the architect desired, the project had an abundance of steel sunshades, screens, canopies, and trellises. The trellis over the south addition had the longest cantilever, 36 feet with a back-span of only 22 feet. The cantilevered beam consisted of a W44x262 and suspended a three-story “billboard” wall clad with perforated metal panels and contained cantilevered 18 inch square HSS beams at each level to resist out-of-plane wind loading.

Completed Building, Food Truck Park and Engineering Quad. Photo: Randy Braley.

Sustainable Design

By utilizing over 80 percent of the original 300,000 SF structure, construction waste was reduced, and carbon emissions significantly decreased thereby reducing negative environmental impact of traditional new construction. The ZACH is now the largest academic building on campus at 525,000 SF and is accessible to engineering students 24/7, which increases the utilization factor and efficiency of the building. The ZACH is large enough to fit two Boeing 747’s placed end to end!

The project also features a 13,000 SF landscaped (green) roof and a 2-acre outdoor green space known as the Engineering Quadrangle (E-Quad). The E-Quad contains a food truck park, rain garden, engineering-focused artwork, seating benches, and picnic pavilions, uniting students from all around campus. Both green spaces contain sustainable materials and low-maintenance native planting.

Rethinking Engineering Education

The facility contains technology-enhanced active-learning studios, interdisciplinary laboratories, 60,000 SF of makerspace (a design center containing machining and fabrication equipment), a student career center, study and gathering spaces, engineering-inspired art, and a green roof where outdoor lectures can be conducted. Interior floor-to-ceiling storefront provides visual access into the fabrication center and engineering laboratories to put engineering education and experiments on full display. Both the function of the facility and the building itself present a positive public image of engineering excellence. As Michael K. Young, President of Texas A&M University, stated at the dedication ceremony, the Zachry Engineering Education Complex is a “stunning feat of engineering.”

The ZACH is not only a display of engineering excellence but a world class facility that brings engineering to the forefront and further cements Texas A&M University’s status as a national leader in engineering education. The building itself serves as a recruiting tool attracting the best and brightest students and professors to TAMU for generations to come.

The post Reengineering an Icon appeared first on Civil + Structural Engineer magazine.



source https://csengineermag.com/reengineering-an-icon/

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