As a result, the masonry on this project progressed in coordination with other trades, rather than in opposition—an obvious benefit to both the contractor and craftworkers. It also provided the opportunity to showcase the benefits of designing and constructing with masonry to the owner, designer, and construction manager/general contractor.
The 4180-m2 (45,000-sf) basement of a research lab featured numerous small rooms and spaces constructed entirely of 5.3-m (17 ½-ft) high CMU partitions, corridor walls, and shaft walls—all grouted and reinforced vertically at 1220 mm (48 in.) on-center (o.c.), and with horizontal bond beams at the mid-spans and the tops of each wall. Typical of laboratories, this project required extensive and well-coordinated MEP and fire protection (MEP) systems running within and through the masonry walls, creating a challenge for all the trades involved.
To simplify construction, the entire project, including the masonry, was built using BIM. The contracting team worked with the architect to develop a 3-D computer model providing all information on the MEP elements passing through and within the masonry walls. This model was particularly useful to the mason contractor, as it consolidated information from other trades and effectively replaced seven individual sets of MEP shop drawings that would have otherwise been necessary.
The BIM model was used to generate dimensioned 2-D plans and elevations that were uploaded to a cloud storage server and accessible to the bricklayers in the field via tablet computer and/or printed drawings. These plans and elevations showed precise locations, sizes, and elevations of more than 1500 penetrations through the masonry walls. The bricklayers then placed their sleeves and box-outs as specified in the BIM model drawings.
As the concrete masonry was constructed, BAC bricklayers installed:
- 468 sleeves for HVAC;
- 69 sleeves for electrical;
- 159 sleeves for mechanical pipe;
- 257 sleeves for fire protection;
- 231 sleeves for plumbing;
- 343 sleeves for water; and
- 10 miscellaneous sleeves.
The total was 1537 sleeves in the masonry walls.
Sequencing of trades
The general contractor made the early decision to sequence the installation of the piping and ductwork within and through the masonry walls at the same time as the masonry construction. Only a few large sections of ductwork direct-mounted to the structural slab above were installed before the masonry.
The contractor rationalized the thousands of pipes and ducts at various elevations would present an unnecessary obstacle to the masons if they were installed prior to the masonry. Conversely, installing the MEP components after the masonry would require excessive cutting through CMU walls, resulting in inefficiencies. Therefore, it made sense to build the block walls with the accommodations for pipes and ducts in a single operation, with the MEP trades working side by side with the bricklayers.
The use of BIM also alerted the contracting team to the option of prefabricating plumbing and gas assemblies—this freed up valuable work space and sped up the construction schedule. The laboratory facility contained 50 lab sinks, 15 toilets, and 50 prefabricated gas assemblies with plumbing running either inside the block walls or in a chase between block walls. For the pipe trades to assemble the piping onsite, per conventional methods, demand for work space would be increased in areas that were already congested. Therefore, the plumbing and gas lines were built in the plumbing contractor’s shop on racks made of steel struts and transported to the site prefabricated. Once they were in place, the bricklayers built their masonry around the plumbing and gas lines.
Weekly job meetings run by the masonry foreman were critical. The MEP trades needed to know the masons’ plans four to five days in advance in order to relocate their manpower from other areas on the job, and to stage their horizontal penetration sleeves and vertical in-wall piping, making sure to have them ready for the masons at the proper time. Each day (sometimes twice daily), the mechanical and plumbing foremen checked in with the masonry foreman on specific labor and material needs.
According to Pete Sindic, project manager of Richards & Weyer Masonry, “There was a high level of cooperation and teamwork between the bricklayers and the other trades throughout the project.”
Chris Coyne, superintendent with Power Construction, agreed with this assesment.
“This was one of the more intense masonry projects I’ve worked on with the prefab MEP units in the masonry walls coupled with all the overhead sleeves and the amount of reinforcing,” he said. “It required a high degree of organization by the masonry contractor, as well as working hand-in-hand with the MEP trades in a team environment.”
“Every day was a new adventure in the basement,” Coyne continued. “Now that the masonry is finished, we all get lost down there due to the amount of masonry walls and the maze-like configuration.”