With joy and gratitude we wish you a wonderful holiday season!
Set to be one of the newest mixed-use residential developments in Los Angeles, CA’s Koreatown, 700 Manhattan is well underway in construction and just completed the basement structure and is beginning to rise above grade. The seven-story, mixed-use-complex will contain 160 residential units, more than 10,000 square feet of ground-floor commercial space, and several amenities including a dog run, and pool/spa deck. Located between Manhattan Place and Western Avenue and 7th Street, the building contains two levels of below grade parking, ground floor retail, parking spaces, and second floor amenity space. Then floors 3 through 7 contain residential units.
Development of the 700 Manhattan mixed-use complex is being performed as a tremendous collaborative effort between Jamison Properties, GMP Architects, Nishkian Chamberlain Structural Engineers and Wilshire Construction.
The structure consists of a cast-in-place concrete system up to the third-floor podium. Floor slabs consist of flat plate, two-way concrete slabs spanning between concrete columns and/or bearing walls. The lateral force resisting system in the building consists of special reinforced concrete shear walls up to the third-floor podium. For levels 3 to 7, the building is of wood framed construction with plywood shear walls as the lateral force resisting system.
Residential development continues in Koreatown and throughout Los Angeles. We appreciate the opportunity to be part of the team on this significant development. The Nishkian firms have extensive experience with multi-family construction development projects. Should you have any questions about an upcoming project, do not hesitate to contact one of our offices.
The recently completed new commercial building, The Palisade, illustrates the changing tide in the fastest growing and highest density of residential neighborhoods on the west end of Bozeman. Nishkian Monks participated in the project as the structural engineer of record, working directly with Bitnar Architects and general contractor Langlas & Associates. Developed by Paine Group, Inc., The Palisade is a 6,600-square-foot commercial building located at 630 Boardwalk Avenue. The structure is located at a gently sloping site. Above grade, the exterior and interior walls are of light-gage metal stud construction with thin set brick veneer at the exterior walls. The roof framing is accomplished with pre-engineered open web steel trusses. The building is founded on conventional concrete strip and spread footings with a slab-on-grade at the ground level.
New tenants Lone Peak Physical Therapy, New Wave Float Therapy, and The Bar Method have moved in. The Palisade was conceived to support Ferguson Farm, the new 19-acre, B2 Zone mixed-use infill development on the north side of Huffine Lane between Cottonwood Road and Ferguson Avenue.
In addition to providing the design of the structural system and construction administration services for The Palisade, Nishkian Monks also served as the primary special inspection agency for this project to help ensure an elevated level of quality throughout the construction process. The Palisade received the 2017 Excellence in Design “Merit” Award by the Montana Chapter of the American Institute of Architects. The award was presented to Thomas Bitnar, FAIA, CKA, LEED AP BD+C at the 2017 AIA Montana Fall Conference in Missoula this fall. A big thank you and congratulations to Thomas Bitnar, the project team, and everyone else involved!
Photo Credit: Zakara Photography
By Robert A. Aman, PE, SE
Many buildings constructed today extend one or more stories below grade level to maximize building area and provide additional spaces for parking, storage, mechanical/electrical rooms, and sometimes even office space or living units. In many cases the soil excavations required for these below-grade structures are constrained by the site’s property lines and surrounding buildings, and therefore require that a vertical excavation cut is made within the property lines and construction boundaries. Since the soil excavations are vertical, temporary excavation shoring must be installed to prevent the soil from caving. In cases where there is available space adjacent to it, the excavation typically will be laid back on a slope at a 1 ½ horizontal to 1 vertical to prevent caving and to eliminate the need for excavation shoring. In situations in which this is not possible, shoring provides a means to safely accomplish the site excavation and greatly improve the utilization of the site development.
The design of excavation shoring can be complex and must take into account many factors, including depth of cuts, groundwater elevations, horizontal loads imposed by soil, resistance loads provided by soil at embedded shoring, and superimposed vertical loads from traffic, construction equipment, construction material storage, and adjacent structures. The vertical loads that occur adjacent to shoring walls usually result in additional horizontal loads applied to the shoring. The geotechnical engineer is responsible for providing all soil design parameters for the temporary shoring design, and works together with the foundation and structural engineer to accomplish this.
Excavation shoring, on most projects, is delegated to a specialty contractor who is also typically responsible for its design. In many jurisdictions, including the City of Portland, excavation shoring design drawings and calculations must be approved as part of the building permit submittal process. Site construction cannot begin without this information in hand, so it is important to understand the jurisdictional requirements before getting to this point so that the start of the project is not impacted.
When needed, there are several different shoring systems that can be utilized. The selection of the best system for each particular project considers the site soil conditions, adjacency with other elements, depth of excavation, and the experience of the specialty excavation contractor. Two common systems are soldier pile walls, and soil nail walls, which we go more in depth about below (pun intended):
Soldier Pile Walls
This method is fast to construct and typically consists of structural steel H-shaped piles that are inserted into a deep round hole filled with concrete that is spaced at regular intervals, usually in the 6- to 12-foot range. The concrete hole is typically 24” in diameter and the H-Pile is 10” to 14” wide/deep. Alternatively, the steel piles may be driven or vibrated into the ground without the use of any concrete. Where the excavation is located adjacent public property, the temporary shoring wall is typically located directly outside the property line, where permitted on a public right-of-way, and is used to apply a reinforced shotcrete wall that then serves as the permanent structural wall. Where shoring walls are located adjacent to a private property it can only be located over the property line with an easement from the property owner.
Between the soldier piles, 4×12 horizontal wood lagging is installed to retain the soil behind the wall. The lagging is installed in 3- to 4-foot increments as the vertical excavation cut proceeds downward. The soldier pile is typically embedded 10 to 12 feet below the bottom of the final excavation, and is designed to cantilever out of the ground. Where the excavation exceeds a range of 10 to 12 feet, the soldier piles may require a soil anchor/tieback or internal diagonal brace near the top of the wall for additional support. For deeper excavations, additional tiebacks are required as the depth increases further.
Soil anchor (or tiebacks) usually consist of a steel tendon or rod encased in a hole filled with a concrete grout mixture. The anchors are tensioned after installation is complete to fully engage the soil. Soil anchor tiebacks are installed at a downward angle and typically extend into the ground a minimum of 25 feet and may therefore encroach into the adjacent properties or the city’s right-of-way (in which case, permission from the property owner is required.) Encroachment into a public right-of-way is typically allowed for temporary construction.
Location of all existing utilities must be confirmed prior to the installation of the anchors. The City of Portland requires an additional encroachment permit, and states that the anchors are de-tensioned after the temporary wall is no longer needed. Additionally, the City requires that any shoring elements in the public right-of-way that are located within 5-feet below grade must be removed, including soldier piles and tiebacks. The use of internal shoring bracing eliminates encroachments, but the shoring is located where the building construction occurs and must not conflict with those activities.
Pros: fast to construct, can be used in deep excavations, flexible layout geometry, can be designed for large surcharge loads
Cons: in certain cases, may require additional soil anchors/tiebacks or support, tiebacks in adjacent property will require an easement, internal braced configurations can be obstructing.
Soil Nail Walls
Another common excavation shoring wall solution is a soil nail wall, which is purely an anchor tieback wall. A soil nail wall consists of steel bars installed in a drilled hole filled with a concrete grout mix spaced at approximately 5 feet on center. The rods are typically installed at a 15-degree downward angle and embedded in the 15-foot range. The nails are then covered with a 4”-thick reinforced shotcrete facing wall that retains the soil behind the wall. The walls are constructed from the top down in 3- to 6-feet-tall sections, depending on the soil type and its ability to withstand caving.
Soil nail walls may be advantageous where overhead construction requirements are tighter because they do not require drilling equipment or the installation of soldier piles. Smaller equipment is generally needed with this method, and no additional embedment of a vertical structural element is required. Embedment of soil nails is also much less than with tieback walls, which may reduce conflicts with adjacent underground obstructions or utilities. A soil nail wall will require a more specialized and experienced contractor, however. Like a traditional soldier pile wall, the structural wall for the building would be a shotcrete wall installed on the face of the soil nail wall. The design of the soil nails is typically provided by the geotechnical engineer, while the shotcrete facing wall is designed by a structural engineer.
Pros: do not require drilling equipment or the installation of soldier piles, needs smaller equipment, no additional embedment of a vertical structural element is required
Cons: limited depth of excavation, limited wall surcharge loads can be accommodated, requires a more specialized and experienced contractor
Basement excavations are a common necessity of many projects, and as you can see above, there are many options and avenues for selecting the right system for each individual project. Developing a strategy to address the excavation is an important part of the early design effort – it helps with creating a scheme that is readily buildable for a specific site and ensures that everything is in place for the permit application. The Nishkian firms are regularly involved in the design of many projects that incorporate basement excavations and are available to consult on your project needs.
Robert A. Aman, PE, SE is an Associate with Nishkian Dean a structural engineering consulting firm in Portland, Oregon.
San Francisco’s Mid-Market neighborhood has seen much development and revitalization over the past few years. Along Market Street, between 5th Street and Van Ness Avenue, apartment buildings, cultural centers, and office spaces are popping up left and right.
Opened in 2013, NEMA, a 35-story apartment building design by Seattle’s Magnusson Klemencic Associates, was the first luxury residential building in the neighborhood. Since then, many other residential buildings, such as the development at Trinity Place, have been constructed or planned. Proper Hotel opened this year and adds to the upscale palate of the neighborhood. A historic flat-iron building, built in 1907, was renovated and retrofitted for this boutique hotel. Proper Hotel’s amenities include ground-level restaurants and a new roof-top cocktail bar.
Nishkian Menninger has had a hand in the development of this up-and-coming neighborhood. 1075 Market and 1066 Market, both mid-rise, concrete residential buildings, will sit across the street from one another. 1075 Market construction is nearing completion and construction of 1066 Market is scheduled to begin this winter.
Renderings of 1066 Market Street on the left and 1075 Market Street on the right.
In addition to new living spaces, the neighborhood has seen a surge in theater and other cultural entertainment spaces. This year, the popular musical Hamilton played at the Orpheum Theater. The sold-out show generated many visitors to the mid-market neighborhood. Out-of-town visitors and city dwellers alike flocked to the theater, creating foot traffic and increasing business in the neighborhood. The Golden Gate Theater and the Strand Theater add to the district’s artistic appeal. The Strand Theater, after years of being closed, was redesigned by SOM and renovated into the home for the American Conservatory Theater.
The tech industry has also contributed to the influx of traffic to the Mid-Market neighborhood. Twitter, Dolby, Spotify, Square, Uber, along with many start-ups, operate out of office space along Market.
During 2017 the Nishkian Chamberlain team in Los Angeles planned various out-of-the-office opportunities for our hard-working team of Engineers, Draftspersons and Administrative staff to enjoy time together beyond just sitting behind a computer screen and crunching numbers. Encouraging departmental integration is essential in today’s business world and out-of-the-office events help integrate our team. Simple conversations help build new professional relationships and understanding of one another’s responsibilities within our organization. And ultimately this improves what we do for you, our Clients!
The Nishkian Chamberlain group attended an LA Kings game earlier this year. Our own Rachel Wong, Kings fan extraordinaire, donned her Official Kopitar Jersey and Bailey hat.
In July we held our annual company picnic at a local park in Culver City and savored delicious food from Santa Maria BBQ. We also played games that included a water balloon toss, corn-hole and human scavenger hunt. It was a fun and relaxing time for all that attended.
We went to a local Dodgers baseball game at the beginning of September. Even non-Dodger fans enjoyed the evening with a Dodger Dog in hand. We’re hoping they go all the way and win the World-Series… GOOOO DODGERS!
Last month we had an opportunity as a team to walk over to the West End Hotel. This historic renovation project in the heart of downtown Culver City will revitalize a local cultural landmark. With interior demolition of wall coverings complete, we were able to observe the complete wood structure as it was originally built from the 1920’s and discuss the changes coming during construction. It was a great team building and learning opportunity for our group.
In December we will hold our annual Nishkian Chamberlain Luncheon. This is one final time for our team to get together outside the office environment and enjoy good food and have a good time all around as we close off another year.
Nishkian Chamberlain is continuously looking for new ways to strengthen teamwork and to improve processes. We feel that the better our team members know each other and engage in conversations they will be empowered to help one another, provide feedback and ultimately provide creative, cost saving solutions for our clients.
A new religious retreat center and community is currently under construction in Sarpy County between Lincoln and Omaha, Nebraska. Cloisters on the Platte is a multi-million-dollar Ignatian retreat community dreamt up and being built by TD Ameritrade founder, Joe Ricketts. The 931-acre oasis is nestled in the rolling hills along the Platte River situated roughly between I-80 on the west and Nebraska Highway 31 on the east. The Cloisters will be comprised of a chapel, the main retreat center, and seven guest lodges. Nishkian Monks is proud to partner with some of the world’s most respected team of architects and artisans to create a tranquil atmosphere that will blend seamlessly with the natural environment along the Platte.
Three of the seven guest lodges– the Campion Lodge, the Kircher Lodge, and the De Brebeuf Lodge—are being built by general contractor Big-D Signature with architectural design by JLF & Associates, and Nishkian Monks serving as the structural engineer of record. The design of the three lodges is inspired by traditional monastic life. The forms are simple and evocative of regional vernacular; the use of reclaimed materials evokes a sense of timelessness. The composition of smaller individual spaces linked by transparent connectors keeps one in touch with their surroundings, simultaneously providing modest contemplative spaces. The lodges are built at a relative level site with some building elements either very close to the water front of a lake or spanning over water features. The buildings are standard light frame wood construction with a combination of heavy stone and reclaimed timber/wood siding at the exterior walls. Steel moment frames and pre-engineered strong walls were required in various locations due to large walls of windows. Roof framing was accomplished with a blend of pre-engineered gang-nailed trusses and stick framing. The combined net area of the Campion Lodge, the Kircher Lodge, and the De Brebeuf Lodge for Lot 5, 6, and 7 is approximately 22,600 square feet. The three lodges are founded on conventional concrete strip and spread footings with bridged connections between structures.
“The Cloisters on the Platte project is a special one in terms of uniqueness and being challenging in creating a distinctive typology for contemplation and reflection– a spiritual sanctuary where art, landscape, and architecture come together to replenish and invigorate the spirit. This is the type of initiative that brings out the best in Nishkian Monks and our partners,” says Ty Monks, Vice-President, Managing Principal, and one of the founders of Nishkian Monks PLLC in Bozeman, Montana. The project is expected to be completed by the summer of 2018.
Check out the flyover video by Lueder Construction showing progress made to the Cloisters on the Platte in Nebraska, Cloisters on the Platte – Construction Update Video
Video Credit: Lueder Construction
Rendering and aerial images courtesy of the Cloisters on the Platte Foundation
We are honored and thrilled that the Q21 mixed-use project in NW Portland was a recent recipient of the Structural Engineers Association of Oregon (SEAO) 2017 Excellence in Structural Engineering Award for a New Building Over $10M. Designed by YBA Architects and constructed by Andersen Construction Company, Nishkian Dean served as the Structural Engineer of Record on the project.
SEAO is a nonprofit organization that works to educate the design industry and the community at-large on structural engineering topics, and provides a valuable forum for structural engineers to interact throughout Oregon.
“We would like to thank SEAO and the awards committee for this honor and we appreciate the continuous efforts of the organization to educate our members and strengthen our industry. We also want to thank the entire Q21 project team and especially YBA Architects for selecting us as the Structural Engineer for such a fun and challenging project.”
Rob Aman, Associate, Nishkian Dean
Located adjacent to the Conway District at NW 21st & Quimby in Portland, the 7-story, 202,200-SF project provides 162 living units, a courtyard, offices, parking, and ground-floor retail. The mixed-use project consists of two 3-story wood-framed residential buildings separated by a courtyard, all of which is situated above a two-level post-tensioned concrete parking structure that is partially below-grade.
The two buildings are connected directly to a seven-story post-tensioned concrete structure that includes residential units at the upper levels, an office floor level, and retail spaces at the ground floor. The concrete structure’s lateral force-resisting system consists of reinforced concrete shear walls, and a seismic joint was detailed to separate the wood and concrete buildings where they adjoin.
A one-story retail space extends off the north side of the structure, and 8 two-story townhomes occupy the ground level along the building’s south side. The project is highlighted by three-story double-tapered steel columns at the main entrance that form an “XXI” shape to symbolize the project name and street number location. These specialty steel columns were constructed with two tapered dodecagon (12-sided) steel sections welded together at the column midpoint to form a double-tapered member. A tapered cantilevered post-tensioned concrete beam spans the top of the steel columns to support four stories of structure above.
One of the most unique and challenging aspects of the project included preserving and modifying the 35-foot tall existing concrete tilt-up wall panels from the existing warehouse building on the site. The team incorporated the panels into the architectural and structural design as a non-structural exterior wall element to preserve the heritage of one of the early buildings that Andy Andersen, the founder of Andersen Construction, constructed and to promote the conservation of materials. This effort was significant and meaningful for Andersen Construction now that the family-owned business is being led by its third generation.
The existing concrete wall panels were cut, reinforced with steel backing and fiber reinforcement, and temporarily braced during construction. A few of the panels were lowered and transported to off-site storage to allow for site access during construction. Nishkian Dean provided full engineering support for this entire process during the initial phase of construction.
“The project afforded many opportunities for creative solutions to meet an ambitious and innovative vision. It was an honor to be a part of the cutting-edge design team on one of the first two-story podium structures in the City of Portland. We are very proud to receive such a prestigious award and grateful to SEAO for establishing a platform to recognize excellence in structural design.”
Dave Beh, Project Engineer, Nishkian Dean
Robert Aman, PE, SE (email@example.com) is an Associate with Nishkian Dean a structural engineering consulting firm in Portland, Oregon.
Dave Beh, PE (firstname.lastname@example.org) is a Project Engineer with Nishkian Dean a structural engineering consulting firm in Portland, Oregon.
Xylia Buros, (Xylia@xyliaburos.com) Marketing Consultant, provided copy and editing for this article.
A challenge of constructing larger and larger projects in dense urban environments is placing those buildings on sites with sub-optimal soil conditions. These sites may include soft compressible layers of native or fill materials, soils that may be subject to settlement during an earthquake due to liquefaction, sites that may be subject to lateral spreading during an earthquake, or conditions that require a high capacity foundation system.
DDC design and construction was performed by Farrell Design-Build Inc. for U.C. Berkeley’s Maxwell Family Field and Garage project in Berkeley, California. The site sits directly adjacent to the Cal Memorial Stadium, the Greek Theatre, and the Haas School of Business.
Traditionally, 2 options have been used to mitigate these conditions:
Both of these options have impacts on the project schedule and cost. Over-excavation requires heavy earthwork equipment, a large site for material storage and creates significant environmental conditions that must be addressed. Installing drilled piers or driven piles can be expensive, time consuming, and loud. Driven piles require traffic considerations and adequate storage, agreements with neighbors, and other environmental considerations.
A new term that has become more prevalent in soils reports and foundation design is Ground Improvement. This has become a generic term for a variety of methods that can be used to mitigate these soft soil sites without over-excavation or deep piers or piles. Ground improvement allows for a shallow foundation system to be used which will save costs and time.
Ground improvement comes in several forms, these include: deep soil mixing, drill displacement piers, and deep dynamic compaction. Deep soil mixing uses augers and other heavy equipment to pump grout and mix it into the existing soil. Deep soil mixing can be spread over a site to support a mat foundation, or can be closely spaced to support concentrated loads. These drilled elements can vary in diameter and depth and produce small amounts of spoils. Another type of deep soil mixing uses vertical blades to cut a trench in existing soil while mixing in a cement slurry. This is called cutter soil mixing with machinery that has blades that can cut through in situ soil up to 130 feet in depth. These improved trenches can be used as stiffen vertical support elements, retaining walls and to restrain liquefiable soil. Deep dynamic compaction uses rams or deep soil vibrators to consolidate and stiffen existing soil or existing soil with added aggregate. Adding grout to the existing soil increases the shear strength, lateral stiffness, and bearing capacity and allows for use of shallow foundation systems on top of the improved subsurface. Since each of these methods involves a specific type of specialized heavy machinery, the exact type of ground improvement will depend on the contractor selected. The result is that ground improvement is typically provided on a design-build basis.
Nishkian Engineers have utilized ground improvement techniques on several recent projects to provide less invasive and more cost-effective foundation solutions. One recent project is The Encore residential development in Redwood City, CA. This 6-story building of concrete and wood frame construction does not have huge foundation loads. However, approximately one third of the building footprint had a subgrade layer of soft material that had a high potential for liquefaction settlement. Ground improvement of this select area was a cost- and time-effective solution to mitigate these conditions in lieu of other, more costly options.
Nishkian worked with Regis Builders, the general contractor, and Farrell Design Build, the ground improvement contractor, to develop the system to support this building. Farrell quickly mobilized their equipment on the prepared site and utilized Drill Displacement Columns (http://www.farrellinc.com/services/foundation-systems/auger-cast-column-drill-displacement-column) up to 30 feet in length to provide support in compression for the foundation and ground floor slab in the soft zones. Farrell also installed displacement ground anchors for tensile resistance under lateral elements. After this quick process the shallow spread footing foundation system was excavated and installed.
Another relevant project is the Maxwell Family Field and Garage which sits directly adjacent to the California Memorial Stadium on the University of California Berkeley campus. Long ago, the site was once a creek bed. During the development of the campus, the creek was turned into a set of large culverts, and filled in to provide a flat surface. This type of loose fill makes building a seismically safe structure more difficult. Similar to the challenges of building on bay mud in San Francisco, the ground could liquefy during an earthquake, resulting in amplified forces on the structure. This condition is exacerbated by the presence of the Hayward fault, which runs just a few hundred feet away from the site. Although there are many ways to improve the soil, the best option for the Maxwell Family Field and Garage project was Drill Displacement Columns (DDC). DDC design and construction was performed by Farrell Design-Build Inc. as well.
Ground improvement installation by Farrell Design-Build Inc. for the Maxwell Family Field and Garage project at the University of California Berkeley campus.
In a previous blog post, building noise and vibration mitigation was discussed as it pertains to tenant improvements (TI) in existing buildings and how the building code sometimes falls short concerning client parameters. As described in the previous post, this is often the case with fitness clubs that move into mixed-use spaces below residential or offices that are sensitive to sound and building vibrations, but the need for vibration mitigation goes well beyond fitness clubs.
The previous blog post examines how performing a finite element analysis of an existing floor system can determine its natural frequency and the natural frequency of a modified, stiffer system. The American Institute of Steel Construction (AISC) has previously put forth a “Design Guide” to design and account for vibrations in new buildings of typical framing. The Design Guide provides for determining perceived floor accelerations that change based on the natural frequency of the floor system. It is of particular note to avoid systems with frequencies that would match those of the space occupied to avoid resonance, where the amplitude of the motions would become very large. These accelerations are compared against recommended peak floor accelerations for human comfort which is dependent on the type of occupancy; offices and residences have a lower threshold than shopping malls and gymnasiums.
However, another increasingly prevalent challenge is the need to design for truck loading on ground floors that serve as drive aisles or emergency access. Conditions can occur where a heavier truck loading is adjacent to retail, office, or residential spaces, or at times, below these spaces either during construction or the lifetime of the structure. Special considerations must then be made to account for the excess vibration that may be encountered as a result of these potentially larger forced vibrations and to design for a higher level of vibration serviceability.
Owners of new buildings typically have two main concerns when considering the effect of adjacent parking or trucking; the transmission of noise and vibration into the sensitive adjacent tenant areas, whether retail, residential, mixed-use, etc. Careful measures and criterion must be developed to mitigate the noise and vibration from the loaded areas from propagating into the more sensitive areas of the structure and disturbing the other building tenants.
In collaboration with an acoustic/vibration consultant, recommendations for the comfort level of all the building tenants will typically determine what treatments need to be made, but the structure itself must be prepared to receive the treatment. Nishkian Chamberlain works with the acoustic/vibration consultant to determine a course of action to be taken and works toward providing a solution to achieve the desired performance.
Nishkian Chamberlain engineers provide building owners, property management organizations, and tenants with a level of confidence that their tenants will be able to cohabitate in a comfortable environment. Should you have any questions about an upcoming or ongoing project, do not hesitate to contact any of our offices. You can also send an email directly to Craig Chamberlin at email@example.com.