Minneapolis-based Meyer Borgman Johnson uses Tekla Structures BIM software to pioneer a powerful new joist and steel procurement process that maintains a hard bid and dramatically reduces the time period between bid and fabrication.
Background
Meyer Borgman Johnson (MBJ) is a full-service structural design and engineering firm in business since 1955. Working from four offices in the upper Midwest and Southwest, MBJ serves a diverse national clientele, based on a culture of integrity, partnership, and expertise. MBJ was swift to embrace 3D modeling as it became an integral part of the construction industry, by implementing company-wide proficiency standards early on.
An emphasis on construction-friendly design throughout MBJ’s history made the combination of 3D BIM and integrated project delivery (IPD) a natural next step. MBJ has successfully implemented this process, also called “IPD structural engineer services,” on a number of projects, including the recently completed retail store in San Clemente, CA.
Seeing an Opportunity
Having recently increased its use of Building Information Modeling (BIM), a Minneapolis-based discount retailer has already seen the benefits of 3D design coordination. The company is still, however, looking for ways to incorporate richer levels of information earlier in the design process to better optimize their designs. One design challenge is the space optimization of roof joists and the various mechanical, electrical and plumbing trades. With steel joist manufacturers typically engaged in the supply chain late in the project schedule, the real, as-built joist information cannot be coordinated during the critical stages of design.
“With BIM analysis tools we knew we could reduce conflicts and increase utilization of the space within our box. We wanted to move beyond that. We wanted to use BIM as a way to figure out what was in there, and then establish that and build in protocols for how we could start to utilize that space to reduce the height of our buildings, or maximize the amount of space we have, or minimize the amount of structure we have to put up.” said the group manager of structural engineering on the project.
Source: BIM on Target, Building Design and Construction Magazine.
Seeing an opportunity for its client, MBJ approached the discount retailer about soliciting the steel joist manufacturers for 3D BIM deliverables for their upcoming project in San Clemente, CA. Using the Tekla Structures BIM software platform, several major joist manufacturers have the ability to receive, convert and publish back as-built BIM deliverables on projects. Providing expertise as the IPD structural engineer, MBJ in conjunction with LTC steel detailers out of LaCrosse, WI, coordinated with the retailer and general contractor, Whiting Turner, how the joist manufacturers would be engaged, and what types of BIM deliverables would be received and provided.
Targeting the Steel Joist Supply Chain
To get joist manufacturer information earlier in the design process, MBJ delivered a Tekla Structures construction BIM model to New Millennium Building Systems, who was awarded the joist package through competitive bidding prior to the steel fabricator being brought on board. With New Millennium already BIM-enabled to receive, detail and then produce BIM deliverables all within Tekla Structures, they were able to help expedite the steel joist shop drawing process. The time from award of joist package to return of approved shop drawings, model and calculations was only 3 ½ weeks.
In addition to coordinating the steel joist delivery process, the MBJ-LTC structural IPD team delivered a Tekla Structures ”product” model as a deliverable for bidding to steel fabricators. This model and approved shop drawings were used to supersede the traditional engineering contract documents as the bid document. By coordinating all the structural trade models within Tekla Structures, MBJ and the project team were able to solve numerous coordination issues before they reached the field.
For example, while coordinating column stability framing with the steel joists, MBJ and LTC found that shim plates were needed to ensure that the channels were level and provided proper slip of the columns. In addition, the left joist end had to be extended to support the channels. That was not picked up in the joist detailing and would have been missed in a regular 2d review.
Another coordination example is a joist bottom chord stabilizer that was not identified in the permit documents. It was originally believed that the bottom chord extension was not needed until New Millennium confirmed that it was needed. Then MBJ designed a hanger and stabilizer connection for the owner to review and accept. This also saved an RFI and field modifications of the beam to account for this condition.
The coordination benefits extended to steel to concrete interfaces as well. Visualizing in 3D, MBJ picked up a coordination issue between the joist embed plates and a wall panel joint where the embeds crossed the panel joint. This was resolved by placing an embed on each side of the panel joint.
The goal was to provide both the structural steel fabricator and steel joist manufacturers well-coordinated, construction-ready design deliverables that could be quickly and accurately absorbed into the fabrication work processes.
Benefits to the Owner
The primary benefits anticipated for this project are more complete and competitive bidding of the steel packages, elimination of change orders related to the steel package, predictable steel erection schedule, and peripheral benefits due to early coordination. The retailer sees benefits when engaging subcontractors early in the design process if their deliverables reduce change orders and enhance downstream coordination.
In the future, additional benefits from reduced overall building height to schedule acceleration and its subsequent revenue recognition could be recognized. ”For this project, a 3 ½ week turnaround of steel joist shop drawings is unheard of in our industry.” – Jerod Hoffman PE, Principal, Meyer Borgman Johnson.