23 minute read
SPOTLIGHT
Modular Challenges and Solutions: The Stack
By Janis B. Vacca, P.E., LEED AP
The Harman Group, Inc. was an Outstanding Award Winner for The Stack project in the 2015 NCSEA Annual Excellence in Structural Engineering awards program (Category – New Buildings $10M to $30M).
As with any novel idea for construction, the key is to not be constrained by the conventional. This can be dif ficult for engineers. Take The Stack, a 38,000 square foot, sevenstory, 28-unit modular apartment building, the first built in New York City. The elegance of the design was in its simplicity. The innovation and challenge of the project was to take basic building materials, utilize them to their maximum efficiency and adapt them for use in modular construction. The project required fabrication, shipping and assembly of 56 modules. Module dimensions and weight were controlled by shipping and crane constraints. Key architectural features that added to the construction challenge were differing geometries on each floor, with balconies, terraces, stained polished concrete floors and cantilevered “boxes”, creating a complex puzzle to be assembled quickly and correctly in the field. Additionally, key to leasing success was designing the modules with an attractive ceiling height. Modules for the 1, 2 and 3 bedroom units were constructed off-site at DeLuxe Building Systems in Berwick, Pennsylvania, and were transported to Inwood, a neighborhood at the northern tip of Manhattan. They were then stacked atop a steel-framed podium level. The modules were approximately 12 feet wide. Floors were framed with 4½-inch thick slabs-on-metal-deck spanning between 10-inch deep “band rail” channels. The channels spanned between rectangular HSS post columns varying in size from HSS 3x3 to HSS 6x3. The 3-inch dimension on the tubes was critical to minimize the dimensional impact of the double walls. All of the structure was fire rated, with inspection and certification occurring in the plant with stickers placed on the boxes prior to shipment. Lateral loads were typically resisted with cross-strap braced frames located within the walls of the modules. The typical gap between the boxes was 2 inches to allow for tolerances. With modular construction, critical loads can sometimes be the transportation loads. If the boxes are not rigid enough, interior finishes can crack. The boxes incorporate the floor framing and ceiling framing for rigidity. With a shipping height limit just above 11 feet, it is a challenge to ship the boxes and attain a ceiling height as close to 9 feet as possible. For The Stack, the ceiling steel framing was limited to 4 inches in depth to maximize the ceiling height. Deluxe Building Systems used an old World War II warehouse to build the boxes in assembly line fashion. Their plant included a concrete batch plant, continuing to add to quality control without consideration of weather effects. Staining and polishing the concrete proved a challenge, particularly with matching seams. The field built ground level steel framed construction was also included in Deluxe’s scope. Shop fabricated “tree columns” were used to support both sides of the boxes. The “tree columns” were erected and connected to girders at the end of these columns to create moment frames, with the boxes sitting directly on the steel. Access was required through the boxes to handle the significant lateral loads being translated to the base building. The Developer, Jeffrey M. Brown, was committed to building the development using modular methods. As with any innovation, challenges were in translating common contiguous features through the modular box joints. With The Stack, there were no common corridors and easily accessed vertical shafts. Modular construction relies on horizontal translation of MEP systems to common vertical shafts. It also relies on corridors to make ugly box to box structural connections. Since this was not feasible for The Stack, interior block-outs in finishes were required to not only connect the boxes, but connect MEP systems. Close communication between the designers and manufacturing personnel was continuous throughout design. All framing and details were coordinated and reviewed with the module manufacturer to confirm that the design was configured in accordance with the capabilities and preferences of the factory personnel. Connection details between the modules were developed such that the boxes could be lowered into place onto alignment pins, and then be bolted or welded in place. Timing was
Courtesy of Gluck+.
important to minimize potential for water infiltration during construction. Temporary roofs were included to minimize this potential. The 56 modules were erected in nineteen days with a single crane and crew of 14 workers. Main stream modular building construction is still feeling its way. As field labor costs rise, determining the best way to build offsite and erect onsite remains a challenge. It is key that all personnel understand the limitations of the construction method. Team members familiar with modular construction are important for success. Early planning is required, with an understanding of financial goals and construction logistics. As with traditional construction, it is necessary to minimize the field construction to put the boxes together. The modular design and construction methods used for The Stack incorporate high quality design and materials into a swift and streamlined process, resulting in an elegant residential building built with maximum efficiency. The lessons learned from this project will further refine the modular design and construction process.▪ Janis B. Vacca is a Vice President and Principal at The Harman Group. She is a member of numerous professional organizations, including the American Society of Civil Engineers, the American Concrete Institute and the Delaware Valley Association of Structural Engineers. Janis may be reached at jvacca@harmangroup.com.
ASSOC I A T I O N S NATIONAL COUNCI L
NCSEA News
Each year the NCSEA Publications Committee leads, edits, reviews, and sometimes even authors design guides on a variety of topics of interest to our structural engineering community. is year has been no di erent. e end of summer 2015 release titled Guide to the Design of Common Irregularities in Buildings, 2012/2015 IBC and ASCE/SEI 7-10 (Prasad et al.) fully explains how and why building irregularities impact structural design and provides detailed examples of how to appropriately analyze and design lateral force-resisting elements for various types of irregular buildings located in Seismic Design Category (SDC) B and D. e book references the 2012 IBC and ASCE/ SEI 7-10, and references material standards from the 2012 IBC by section number. It is also applicable to the later versions of these standards and the 2015 IBC. Four detailed design examples include an overview of applicable irregularities, a discussion of appropriate analysis and design requirements, determination of key lateral force-resisting system demands, and design of select example elements contained in the building’s load path. In conjunction with the release of the irregular buildings publication, NCSEA is also o ering a live course. e course provides an overview of the book material and includes approximately 25 percent new material not included in the actual publication to help the engineer better understand the fundamental theory behind the practical example problems, and to verify approaches used with hand calculations and simple computer modeling results. e 4-hour NCSEA Diamond approved course can be provided as a stand-alone course or as part of an arranged program such as an NCSEA Member Organization meeting. All attendees receive one copy of the new guide. e committee has completed its nal technical review of a second publication, a relatively shorter guide on the design of glazing as a structural element. e purpose of this design guide is to provide the structural engineer with su cient background knowledge and current methods to determine the speci cation of glass elements in buildings. It is aimed at structural engineers who are experienced in designing building structures and elements using traditional materials but with little to no experience in using glass to transfer forces. A publication date of spring 2016 is expected. With the help of a few external authors, the committee is working on quite an exhaustive design guide on foundation design for structural engineers. e publication will be titled Guide to the Design of Building Foundations in Accordance with the 2015 IBC and ASCE/SEI 7-10. is practical design guide will be a problem based step by step review of all major provisions contained in Chapter 18 of the 2015 IBC. Emphasis will be placed on structural provisions and interaction with geotechnical engineers. e committee is aiming for a 2016 release of this publication. Unrelated to the foundation design guide, the committee is days away from reviewing the nal draft of Guide to the Design of Shoring Systems and plans to release this publication in Summer 2016. It will include the following examples with full connection details, speci cations, and pictures: • Typical sheet pile wall applications • Cantilever steel soldier pile wall • Restrained (i.e. tiebacks) steel soldier pile wall • Soil nail wall • Deep soil cement mixed walls for excavation e Young Members Group is continuing to work with the Publications Committee on a practical-topics-for-young-engineers training guide. e group is focusing on the development of webinars rst and then plans to expand the webinars into a training guide. Webinars are already being planned for 2016.
Timothy W. Mays, Ph.D., P.E. Publications Committee Chair
New and Improved!
NCSEA is pleased to announce that its provision of live webinars, certi cates, and recordings has been updated; and its recorded webinar library is now automated. Viewers can watch recorded webinars anytime of the day or night, take quizzes, and receive certi cates. In addition, changes were made that will allow NCSEA to drop the $30/ recorded webinar fee for subscribers, beginning February 1. ere is no time like the present to become a subscriber. For $995, you receive one year of live webinars (at least 20/year) and as many NCSEA online recorded webinars as you would like to watch.
NCSEA Webinars
February 11, 2016 Steel Curtain Walls Chuck Knickerbocker, Curtainwall Manager, Technical Glass Products February 23, 2016 Welded Connections: the Good, the Bad, and the Ugly Duane K. Miller, Sc.D., P.E., Lincoln Electric March 22, 2016 IBC Chapter 17: Special Inspections and Testing Chris Kimball, P.E., S.E., Kimball Engineering STRUCTURAL CONTINUING EDUCATION ENGINEERS NCSEA More detailed information on the webinars and a registration link can be found at www.ncsea.com. Subscriptions are available! 1.5 hours of continuing education. Approved for CE credit in all 50 states through the NCSEA Diamond Review
Diamond Reviewed Program. www.ncsea.com.
How do you defi ne success?
How does your rm function compared to other AE rms?
e Winter Leadership Forum is an opportunity for setting new goals. Can your rm be more e ective, in uential or successful in 2016 and beyond?
Don’t Be Left Out!
Sessions on ursday will be interactive and focus on project and employee risks:
What’s the Best Project Delivery System for You? Methods, Advantages & Disadvantages is interactive workshop will explore virtually every aspect of modern project delivery and the advantages and disadvantages of each method, with a deep dive into results of major studies that document what works and what doesn’t in the design and construction industry. – Dale Munhall, Architect, Director of Construction Phase Services, Leo A Daly
Managing Your Staff Update on Employment Law – Troubleshooting – Staci Ketay Rotman, Attorney, Franczek Radelet P.C. How to achieve your business objectives while minimizing the risks of litigation. Topics include: • Hiring the Best Candidate…Lawfully! • Properly Classifying and Paying Your Workers • Independent Contractor v. Employee • Exempt v. Nonexempt • Preventing Discrimination & Harassment in the Workplace • e Handbook: Informing Employees of Policies & Procedures • Disciplining the Problem Employee
Sessions on Friday will test you on professional liability risk before and after it becomes reality:
Professional Liability Risk Management Identify, Evaluate & Manage Risk – Dan Bradshaw, CPCU, Benchmark Insurance Agency – Craig Coburn, Attorney, Richards Brandt Miller Nelson Professional liability claims typically start with a real or perceived technical issue and evolve into a full- edged claim because of a poor business decision. In this session, attendees will learn (or be reminded of) how these factors combine to spawn a professional malpractice claim and gain valuable insight on how to better identify, evaluate and manage professional liability risk before it becomes reality and after it becomes a claim.
Risk becomes Reality: Claims Management Interactive Discussion of Three Lawsuits – with the engineers that were sued and the attorneys that represented them – Seasoned (been sued) structural engineers and defense counsel; moderated by John Tawresey, S.E., retired VP & CFO, KPFF Structural engineers and defense counsel from three rms will present what happened to them when they were sued for professional negligence; and the audience will have an opportunity to predict the outcome.
The Winter Leadership host hotel is the Coronado Island Marriott Resort & Spa, featuring a full-service spa, three heated pools and convenience to beautiful sandy beaches, shopping and restaurants at Ferry Landing. The WLF room rate is $239 with a complimentary resort fee (a $25 value). Coronado Island, situated just across the Big Bay from downtown San Diego, is known for two famous structures, the historic Hotel del Coronado and the distinctive San Diego-Coronado Bridge. Beyond these architectural/structural marvels, the quaint island offers beautiful beaches, restaurants, galleries and unique shopping experiences. Take a ferry across the Bay to explore San Diego–stroll through Old Town and the Gaslamp District, explore the museums and gardens of Balboa Park, or go whale watching. Register online and make hotel reservations now at www.ncsea.com!
NCSEA News
T R U C TURAL S
ASSOC I A T I O N S NATIONAL COUNCI L
The Newsletter of the Structural Engineering Institute of ASCE Structural Columns
Save the Date
2017 STRUCTURES CONGRESS
April 6 – 8, 2017 Denver, Colorado
WITH SEI SUSTAINING ORGANIZATION MEMBERSHIP
Increase your exposure to more than 25,000 SEI members through www.asce.org/SEI, SEI Update e-newsletter, STRUCTURE magazine, and at SEI conferences year round.
www.asce.org/SEI-Sustaining-Org-Membership
Local Activities
Maryland Chapter
Th e SEI Maryland Chapter was selected as the 2016 SEI Chapter of the Year. Th eir commitment to provide high quality events for membership, and signifi cant outreach to the next generation of structural engineers, continues with a full slate of recent activities. Th e chapter hosted a presentation about the restoration of the Th omas J. Hatem Memorial Bridge and the T.R. Higgins Lecture at Morgan State University. Th ey also conducted a construction tour of a new terminal connector at BWI Airport. For more details, see the full story on the SEI News page at the website.
Get Involved in SEI Local Activities
Join your local SEI Chapter, Graduate Student Chapter, or Structural Technical Groups (STG) to connect with colleagues, take advantage of local opportunities for lifelong learning, and advance structural engineering in your area. If there is not an SEI Chapter or STG in your area, talk with your ASCE Section/ Branch leaders about the simple steps to form an SEI Chapter. Visit the SEI website at www.asce.org/SEI and look for Local Activities Division (LAD) Committees.
Join SEI as a Sustaining Organization Member to raise recognition for your organization with decision makers in the structural engineering community year-round, and to show your leadership and support for SEI to advance and serve the structural engineering profession. Demonstrate your commitment and increase your organization’s visibility with more than 25,000 SEI members and at SEI conferences through www.asce.org/SEI, the monthly SEI Update e-newsletter, and STRUCTURE magazine. We hope you will join Hayward Baker, International Code Council, and Simpson Strong-Tie in support of SEI as an SEI Sustaining Organization Member. Learn more at
www.asce.org/SEI-Sustaining-Org-Membership
Questions? Contact Suzanne Fisher sfi sher@asce.org.
Register for ASCE Week
March 14 – 18, 2016, Orlando, Florida
Save up to $900 and earn up to 36 PDHs. Choose from 10 seminars including structural and professional practice topics. In addition, a private Behind-the-Scenes Disney Tour, including the Utilidors, is available. Book one seminar now and save up to $350 off regular seminar prices; book two seminars and save up to $1,300 through February 19, 2016. View the schedule and register at www.asce.org/asceweek.
Errata
SEI posts up-to-date errata information for our publications at www.asce.org/SEI. Click on “Publications” on our menu, and select “Errata.” If you have any errata that you would like to submit, please email it to Jon Esslinger at jesslinger@asce.org.
On May 20, 2013, the third violent tornado in 14 years tore through Moore, Oklahoma, creating a path of destruction through dense residential areas and damaging several critical facilities. Nearly 1,100 single-family homes were leveled, and 24 people died. Moore, Oklahoma, Tornado of 2013: Performance of Schools and Critical Facilities presents the observations, findings, and recommendations of a team of structural engineers and construction specialists who assessed the structural damage to nonresidential buildings. The team investigated the tornado’s effect on schools, a medical center, and buildings supported by long-span structural systems. They found that the most common structural failures related to masonry and steel framing. Topics include: • a history of significant tornado events in Moore, Oklahoma • results of damage assessments and a summary of observations for a medical center, five schools, a bowling alley, and a strip mall • a survey of building codes and relevant standards used in
Moore • conclusions with recommendations The damage assessments and, more importantly, the recommendations for strengthening new and existing critical facilities will be of interest to structural engineers, architects, building owners, local officials, and code developers working to reduce the damage caused by high-wind events.
In Seismic Evaluation and Retrofit of Existing Buildings, Standard ASCE/SEI 41-13, a three-tiered process is established for seismic evaluation according to a range of building performance levels. Tier 1 evaluation focuses on identifying potential deficiencies in existing buildings based on the performance of similar buildings in past earthquakes. The systematic procedure sets forth a methodology to evaluate the entire building in a rigorous manner. Tier 1 Checklists for Seismic Evaluation of Existing Buildings: Fillable Forms for Standard ASCE/SEI 41-13 is a complete collection of the screening checklists included in Appendix C of Standard 41-13. The evaluation checklists, covering a variety of building types and seismicity levels, are now offered as fillable PDF forms that can be completed using Adobe Acrobat Reader. The collection of 34 forms includes the summary data sheet, Life Safety and Immediate Occupancy checklists for basic configuration and 15 building types, and a nonstructural checklist. Each form contains criteria for four seismicity levels: very low, low, moderate, and high.
Building information modeling (BIM) has become a significant area of endeavor in the architecture, engineering, construction, and operations (AECO) industries. The models generated from BIM are being used for analysis and design of buildings and other infrastructure. The ability to integrate schedule and cost data with the analysis and design process makes BIM a very useful tool. Building Information Modeling contains 13 chapters, contributed by international researchers and practitioners, that present a comprehensive overview of the recent advances in the application of BIM across the AECO industry. The use of BIM is examined as a framework for structural design; in cost estimation; in adaptive cyber-physical systems; in construction progress monitoring and project management; in green building project delivery; in commissioning and facilities management; in military construction; in model assessment; and in integration with augmented reality. Engineers, architects, contractors, building owners, facility managers, as well as researchers, will find this publication a valuable resource.
Design of Latticed Steel Transmission Structures (10-15)
This standard provides requirements for the design, fabrication, and testing of members and connections for latticed steel electrical transmission structures. Covering guyed and self-supporting structures, these requirements are applicable to hot-rolled and cold-formed steel shapes. The standard specifies the design criteria for structure components – members, connections, and guys – to resist design-factored loads at stresses approaching yielding, buckling, or fracture. This new edition, which replaces the previous Standard ASCE 10-97, presents minor changes to the design requirements and introduces new sections on redundant members, welded angles, anchor bolts with base plates on leveling nuts, and post angle member splices. Topics include: • loading, geometry, and analysis • design of members, including compression members, tension members, and beams • design of connections, including fasteners, minimum distances, and attachment holes • detailing and fabrication • full-scale structure testing • structural members and connections used in foundations • quality assurance and quality control Standard ASCE/SEI 10-15 is a primary reference for structural engineers designing latticed steel electrical transmission structures, as well as for other engineers, inspectors, and utility officials involved in the electric power transmission industry. Visit the ASCE Bookstore at www.asce.org/Books_Standards to purchase these and other structural books.
CASE in Point
CASE has updated and released Tool 4-3: Sample Correspondence Letters, the most comprehensive CASE tool that provide sample letters aiding the firm in daily operations. This tool was updated in 2015 to include: • A new section containing sample collection letters, including both a model lien letter and model audit inquiry letter. • New letters about contracting directly with a geotechnical firm • New letters about job site hazards CASE Tools are developed and released with the sole purpose of ensuring CASE members manage risk and safety when engaging in structural engineering projects. We encourage you to download them and incorporate them into your business. You can purchase this and the other Risk Management Tools at www.acec.org/bookstore.
Donate to the CASE Scholarship Fund!
The CASE scholarship, administered by the ACEC College of Fellows, is awarded every year to a deserving student seeking a Bachelor’s degree, at minimum, in an ABET-accredited engineering program. Since 2009, the CASE Scholarship program has given over $17,000 to engineering students to help pave their way to a bright future in structural engineering. We encourage our fellow structural engineering colleagues to support this popular and successful program. Your contribution today will help CASE and ACEC increase scholarship funds to promising students who need them most. This is an exceptional opportunity to encourage growth in the structural engineering profession and ensure that the highest caliber of students become the future of our industry. Your monetary support is vital in helping CASE and ACEC increase scholarships to those students who are the future of our industry. All donations toward the program may be eligible for tax deduction and you don’t have to be an ACEC member to donate! Contact Heather Talbert at htalbert@acec.org to donate.
CASE Risk Management Tools Available
Foundation 1 Culture – Create a Culture of Managing Risks & Preventing Claims
Tool 1-1 Create a Culture for Managing Risks and Reducing Claims The most comprehensive CASE tool that provides sample templates and presentations that aid in creating a culture of risk management throughout the firm. Tool 1-2 Developing a Culture of Quality This tool was developed to identify some ways to drive quality into a firm’s culture. It is recognized that every firm will develop its own approach to developing a culture of quality, but following these 10 key areas offer a substantial starting point. The tool includes a white paper and customizable PowerPoint presentation to facilitate overall discussion.
Foundation 2 Prevention & Proactivity – Act with Preventative Techniques, Don’t Just React
Tool 2-1 A Risk Evaluation Checklist Don’t overlook anything! A sample itemized list of things you should look for when evaluating a prospective project. Tool 2-2 Interview Guide Getting “the right people on the bus” is one of the most important things we can do to mitigate risk management and yet we never learn about interviewing skills in school. It is the second tool related to the Second Foundation of Risk Management, Prevention and Proactivity. The tool will help your firm conduct higher quality interviews and standardize the process among all your staff. Tool 2-3 Employee Evaluation Templates This tool is intended to assist the structural engineering office in the task of evaluating employee performance. The evaluations provide a method to assess employee performance and serve as an integral part of the company’s risk management program. Tool 2-4 Project Risk Management Plan This plan will walk you through the methodology for managing your project risks, along with a few common project risks and templates on how to record and track them. Tool 2-5 Insurance Management: Minimize Your Professional Liability Premium This tool is designed as a guide to help you provide critical additional information to the underwriter to differentiate your firm from the pack. You can purchase these and the other Risk Management Tools at www.acec.org/bookstore.
Engineers to Lead, Direct, and Get Involved with CASE Committees!
If you’re looking for ways to expand and strengthen your business skillset, look no further than serving on one (or more!) CASE Committees. Join us to sharpen your leadership skills – promote your talent and expertise–to help guide CASE programs, services, and publications. We have a committee ready for your service: • Risk Management Toolkit Committee: Develops and maintains documents such as business practices manuals and policies for engineers under CASE’s Ten Foundations for Risk Management.
Follow ACEC Coalitions on Twitter – @ACECCoalitions.
Expectations and Requirements To apply, you should • be a current member of the Council of American
Structural Engineers (CASE) • be able to attend the groups’ two face-to-face meetings per year: August, February (hotel, travel reimbursable) • be available to engage with the working group via email and conference call • have some specific experience and/or expertise to contribute to the group Please submit the following information to htalbert@acec.org • Letter of interest • Brief bio (no more than 2 paragraphs) Thank you for your interest in contributing to your professional association!
Share Innovative Ideas!
Does your firm have an innovative idea or method of practice? Looking to get more involved on short duration projects? We are inviting you to “share the wealth” and submit a proposal for a web seminar topic, publication, or education session you would like to see CASE present at an upcoming conference. Our forms are easy to use and you may submit your information via email. Go to www.acec.org/coalitions and click on the icon for Idea Sharing to get started. Questions? Contact us at 202-682-4332 or email Katie Goodman at kgoodman@acec.org. We look forward to helping you put your best ideas in front of eager new faces!
ACEC Business Insights
Best Management Strategies in Business of Design Consulting Course
March 23 – 26, 2016; Denver, CO ACEC’s highly regarded Business of Design Consulting course is a unique playbook for building leadership and managing your firm at the most effective levels. The 3½-day agenda is taught by an experienced faculty of industry practitioners and highlights current strategies for a wide array of critical, need-to-know business topics that will keep your business thriving despite a churning business environment, including how to manage change and build success in performance management, strategic planning and growth, finance, leadership, ownership transition, contracts and risk management, marketing, and more! For more information and to register for the course,
www.acec.org/calendar/calendar-seminar/business-of-
design-consulting-denver-2016.
Applying Expertise as an Engineering Expert Witness – SAVE the DATE!
May 19 – 20, 2016; Chicago, IL Engineers are often asked to serve as expert witnesses in legal proceedings – but only the prepared and prudent engineer should take on these potentially lucrative assignments. If asked, would you be ready to say yes? Developed exclusively for engineers, architects, and surveyors, this unique course will show you how to prepare for and successfully provide expert testimony for discovery, depositions, the witness stand, and related legal proceedings. Applying Expertise as an Engineering Expert Witness is a focused and engaging 1½ day course that will run you through each step of the qualifications, ramifications, and expectations of serving as an expert witness. For more information about the course, check www.acec.org/ education/seminars. Registration opens in March.
