San Jacinto College Anderson-Ball Classroom Building
San Jacinto College Anderson-Ball Classroom Building
San Jacinto College’s newest project, a 120,000 square foot classroom building, will be the largest instructional building in the U.S. constructed from mass timber. The floor plate is made of cross laminated timber with an acoustic mat covered in a concrete topping layer. The floors are supported by glulam girders spanning in one direction only and framing into glulam columns. The building’s lateral system consists of a combination of steel brace frames, and glulam brace frames. The building’s cross laminated timber roof is designed to accommodate total coverage with solar panel arrays. Fire rating around the building stair wells and elevator shaft is achieved by utilizing cross laminated timber walls. The mass timber framing production and erection including connections was provided by a sole source supplier selected from an interview process conducted by community college representatives, the general contractor, architect, and structural engineer. BIM coordination efforts between the general contractor, architect, subcontractors, and engineers began once the mass timber supplier was selected, giving the team a head start on constructability issues and schedule.
The building has a diverse program of spaces and uses. It contains 60 typical classrooms, faculty offices, a large presentation hall, lecture hall, robotics laboratory and a double height grand lobby space to welcome visitors. The lobby space includes several key mass timber building components, a monumental stair made of glulam beams, a bridge spanning across the short length of the lobby at level 2 made of glulam beams, and cross laminated timber floor panels, cross laminated timber feature walls, and a walkway spanning the long distance of the lobby at level 2 suspended by steel rods from the mass timber structure at the lobby roof. The third floor of the building contains office space and flexible workstation spaces which required a layout different from the classroom spaces below. In order to address this change of program and wall layout, the building lateral system was modified at the third floor so that the steel braces could be configured differently than below.
The new building has a modern facade system that reflects the current aesthetic of the San Jacinto Community College campus while giving it a modern update. The main enclosure system consists of brick, metal panels, and large expanses of curtain wall. Tall heights of curtain wall are supported by glulam girts as required by the curtain wall supplier. Brick stacked over three levels high is supported on steel shelf angles attached to the mass timber floor plate and glulam girders. The building includes three exterior stairs that are partially enclosed by a decorative clay masonry system that has regularly located openings to match existing masonry screen walls at adjacent buildings.
During the concept phase of design, the college engaged the design team and two general contractor’s to produce a cost comparison between a building constructed of mass timber and a comparable steel building. One contractor concluded that the mass timber building would be 18% more expensive while the other concluded that it would be 0.5% less expensive. This exercise gave the college confidence that they could proceed with the mass timber structural system and keep the project within their budget.
The new classroom building is a sign of San Jacinto Community College’s commitment to mass timber. The college has used this building as a platform to promote the use of mass timber in the Gulf Coast region by hosting a series of mass timber conferences. The first Texas Gulf Coast Mass Timber Conference was held at the college campus over two days in February 2020. Presenters included the design architect, American Wood Council, Woodworks, the general contractor for the building, a fire-safety consultant, and a general contractor with previous experience building mass timber buildings. The second Texas Gulf Coast Mass Timber Conference is scheduled for April 2021 and will include tours of the building under construction.
Walter P Moore has worked with multiple partners in the design and construction process to ensure that the project is successful and exceeds industry standards. We are engaged with a vibration monitoring firm hired by the college to install vibration testing equipment in the building so that the vibration characteristics can be understood once the building is in use. During design, we worked with the owner, architect, and mass timber provider to ensure that the connection between mass timber elements were detailed in such a way as to reduce potential maintenance issues such as janitorial damage to wood column bases. We worked closely with the mass timber provider to ensure that the connections of the mass timber structural elements were fully understood and approved by all parties before arriving onsite. Also during design, we provided the general contractor with two schemes for wind force resisting systems, one using steel brace and glulam brace frames, and the other using cross laminated shear walls. This exercise led the team to choose the brace frame option due to its lower cost, foundation implications, and flexibility it provided in the floor plan. The building was intended to be supported on existing foundations once used by a previous building on the site. We worked with the contractor and architect to determine the best fit possible between the new structural layout and the existing foundation layout. During construction we worked closely with the general contractor to quickly resolve unforeseeable conditions in the existing foundation system. Walter P Moore understands that the utilization of a mass timber structural system requires a closer relationship between the design team, ownership, general contractor, and subcontractors than many typical structural systems.