In the News
July 26, 2018
Let’s talk tilt.
Multi-story tilt-up buildings have a narrow, but growing, niche in Utah. Several aspects of a building determine whether they are good candidates for tilt-up. There are several unique factors to consider in a multi-story tilt-up building when compared with single-story tilt-up buildings.
Panels setting during construction of the UPS Distribution Center | Salt Lake City, Utah
Multi-story tilt buildings in non-seismic areas can easily be five or six stories tall. Cost savings are derived from quick construction. Concrete tilt-up is inexpensive compared with a steel building with glazing of the same size. Utah is in a high seismic region, so economic buildings tend to be shorter, usually three stories or less. The cost savings are multiplied with taller buildings so multi-story tilt-up usually has a smaller cost difference compared with a steel building with glazing in Utah. Despite the limited height, these buildings seem to be gaining popularity. Recently Dunn Associates designed a two-story tilt up called the U of U Support Services Center, located South Jordan, Utah. This will be a two-story building. Airport Technology Parking (ATP), another project at the Ogden Hinckley Airport in Ogden, Utah is a three-story tilt-up building. If there is a situation where the budget is tight or there is a willingness to trade some of the glass on the outside for a nicer interior, this kind of a building could be a good fit.
Other aspects of a building that make it a good candidate for tilt-up construction include square footage, repeatability, and the scale of the project. The savings of height is often made up for with a shorter building with a comparable square footage. If the building is larger such that masonry becomes more expensive, and fire codes prohibit wood construction, this could be a good fit. Many warehouses, like UPS Distribution Center in Salt Lake City, Utah are tilt-up for these reasons. If the panel design is repeatable, then it saves time on the building construction. The two-story U of U Support Services Center, for example, only had two different kinds of panels. If the building is part of a series of similar buildings that have a repeatable design, tilt-up would also be a good candidate. Large campuses of warehouses like Freeport, in West Valley City, Utah or Business Depot Ogden (BDO) in Ogden, Utah.
Panels setting during construction of the doTERRA Bottling Plant | Pleasant Grove, Utah
One, two and three-story tilt-up buildings have some similarities and some differences. There are code requirements for that all tilt-up buildings must satisfy. As a building gets taller, more requirements are added.
Some design considerations for a one-story tilt-up building are seismic out of plane bending in the wall and jamb thickness. Walls are affected by loads from a seismic event out of plane, and the wall needs to withstand this load. Out of plane loads become especially important on a garage door lintel in a tilt-up wall. The wall thickness can be affected by this load. More space may be required to fit the reinforcing in the wall to resist the forces.
Wide jambs are preferable from a design perspective to narrow jambs. When jambs are wider, the special moment frame provisions in the code can be avoided. Otherwise there is a high percentage of steel reinforcing in the jambs. This can be difficult to construct causing issues like honeycombing. The added cost of the steel repeated at every jamb that is that narrow can significantly increase the cost of the building when compared with a thicker jamb that is not in the special moment frame provisions. The cost of jambs that become honeycombed and must be repaired or repoured compounds the cost.
Two-story buildings are similar to one-story buildings because many of the aforementioned factors are still a concern. However, there are a few key differences. Two story tilt-up buildings are often controlled by overturning. This comes from having multiple diaphragms that are heavier than a one-story building. The additional floor is usually concrete on metal deck compared to just a metal roof. This adds to the seismic weight of the building, which influences overturning. Overturning is also influenced by the building height. The building may be taller than a one-story office, increasing the moment arm for the overturning. Overturning can be mitigated by welding together the panels using embeds, so that they act as one unit.
Construction of the UPS Distribution Center | Salt Lake City, Utah
As the building gets taller the vertical stresses on the building increase from the increased weight. Three-story buildings have all of the previously mentioned design considerations but are often controlled by a different aspect of the design. Jambs are again the concern as in one-story buildings, but for a different reason. Instead of lateral forces causing the jamb to be larger, the axial force controls. The ACI 551.1R-14 Section 4.2 requires that the maximum axial stress on the design width bd be limited to 0.06f’c . This provision requires the building to become thicker at the jambs, or to have a higher strength concrete.
Tilt-up buildings taller than three stories are possible in Utah, but usually are not cost effective. The volume of concrete and the compressive strength of concrete must be increased to satisfy the 0.06*f’c*Ag requirement, and this increases the cost significantly. Currently intermediate concrete shear walls, the type of walls typical of a tilt-up building, are limited to 40ft. Cost comparisons, including labor and material costs, are always variable and constantly being evaluated. This concept, in addition to advancements in system testing and code acceptance may provide a way to make them cost-effective in the future.
So, what does all of this mean? In Utah, multi-story tilt-up buildings can save the owner money. They can be a cost-effective option for larger buildings with a repeatable design that are part of group of buildings.
By | Gilbert Nichols, MS
Gil received his Bachelor of Science in Civil Engineering in 2015 and his Master of Science in Structural Engineering in 2017 from Utah State University. He is an avid runner and especially loves trail running. Say hi if you see him out on the trail!
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Dunn Associates, Inc. is growing strategically and looking for the best people. As a leading structural engineering firm in the intermountain area for over 20 years, Dunn Associates continues to be involved with some of the best projects in the region. Exclusively focused on structures, we innovate, create and optimize unique structural solutions for our loyal public and private clients.
The successful candidate will first and foremost be required to have high personal skills while interacting with our clients. We are professional consultants and our attitudes and manors are of high importance. Interaction with design and administrative professionals within our office is expected.
STRATEGIC MARKETING PLAN – Continue to implement the overall strategic plan regarding Dunn Associates, Inc. and its marketing endeavors.
CLIENT RELATIONS – Work closely with principals, associates and others to foster and advance relationships with top clients and potential clients. Leverage a network of relationships with key decision-makers, primarily with owners, architects and contractors, to establish good will, share project leads and expand opportunities with the public sector clients.
PROPOSALS / QUALIFICATIONS – Respond to RFPs and RFQs, including requests by architects and contractors who are responding to RFPs and RFQs, develop the appropriate material to leverage Dunn Associates’ qualifications in regard to the specified projects. Follow self-established and business development leads to track projects both prior to and following the submittal of Statements of Qualifications and Proposals.
DATABASE MANAGEMENT – Update information kept in company database (Cosential & Deltek Ajera), including contacts, projects, prospective projects and workload. Work closely with project managers and engineers to develop content for use on the website, in firm profiles, social media, and in RFPs and RFQs. Work with project managers and in-house photographer to acquire photos of current and past projects for use in marketing efforts.
PUBLIC RELATIONS – Develop opportunities with news and media organizations to promote Dunn Associates, Inc., its personnel, projects and other accomplishments. Create advertisements according to publication specifications, contract for the advertising space and track the results of advertising efforts. Update and upgrade company website as necessary and appropriate. Work closely with project managers to develop content for bi-weekly posts to news/blog page. Create consistent and meaningful content for social media to increase company exposure for client relations and staff recruiting efforts. Attend industry-related events. Prepare and submit industry-specific award opportunities for staff and projects.
ADMINISTRATIVE SUPPORT – As necessary, provide phone support and assist administrative staff in carrying out their assignments including professional licensing, staff recruiting and human resources, workload, and company-sponsored events.
- Education—Bachelor’s degree; qualified experience may substitute for college education.
- A working knowledge of marketing-related softwares Adobe Creative Suite (InDesign, Photoshop, Illustrator), Microsoft Office are required. Experience with CRM (Cosential) and/or Deltek Ajera a plus.
- Experience working in the construction or professional services industry.
- Established rapport with key decision-makers in the construction industry, particularly architects and contractors would be added value.
Compensation is very competitive and varies with experience. Dunn pays full medical for the employee and their dependents, covers full dental for the employee, life insurance policies, engages in 401k matching, contributes $2,000 annually to HSA (Health Savings Account), and gives generous PTO (including holiday and vacation days). Other perks to be discussed as the dialog progresses.
How to Apply:
Submit resume and cover letters to firstname.lastname@example.org or submit through online form.
Dunn Associates, Inc. (DAI) is a full-service structural engineering firm specializing in both public and private clients. We believe in an upbeat work environment while providing our clients with cutting-edge design solutions that consistently exceed expectations.
We are currently looking for a highly motivated designer/drafter with great communication skills. At least two years of experience with Revit is preferred, but all commercial structural design candidates will be considered.
Dunn Associates, Inc. offers competitive pay and a full benefits package. Submit resume online or email to email@example.com.
Dunn Associates, Inc. is a leading structural engineering firm in Salt Lake City, Utah. We believe in an upbeat work environment while providing our clients with cutting edge design solutions that consistently exceed expectations. We are looking to add a new member to our team to answer phone calls and provide general office support to the staff.
The desired candidate will possess the following skills:
• Effective management of multi-line phone system and presenting a friendly, professional impression for clients and visitors.
• Ability to multi-task.
• Proficient in Microsoft Office software (Word, Excel, PowerPoint) and experience with Adobe Acrobat or Bluebeam.
• Ability and willingness to work in a team environment.
Job Duties include but are not limited to:
• Greet and direct visitors; answer multi-line phone in a pleasant, professional manner.
• Provide administrative support to upper management and principal engineers.
• General office duties will include lobbies & break room area upkeep, meeting scheduling, restock & order supplies.
• Organizing and filing drawings and project folders.
• Sort incoming mail and create outgoing shipments as needed.
• Perform various office duties as assigned.
Dunn Associates, Inc. offers competitive pay and a full benefits package. Submit resume online or email to firstname.lastname@example.org