TPB Exterior Envelope Restoration And Structural Improvements Fall - - PDF document

TPB Exterior Envelope Restoration And Structural Improvements Fall 2013

Synopsis History............................................................................................................................Page 2 Condition Assessment ............................................................................................................3 Options....................................................................................................................................6 Recommendation....................................................................................................................7 Applicable City Policies/Audits................................................................................................8 Financing Approach ................................................................................................................8 Integration with Space Plan ....................................................................................................8 Challenges Facing This Project ..............................................................................................9 Upcoming Council Packages ..................................................................................................9 Next Steps...............................................................................................................................9 Background and Technical Support Documents Previous Study/Repair Timeline Envelope Failures by Elevation Damage Photos by Material Assembly Condition Assessment, from FFA Architecture, Assessment Phase I Structural Assessment, from KPFF, Assessment Phase I Appendix Project Budget Financing Cost Estimate Draft Project Schedule

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History Construction of the Portland Building was completed in 1982, making the building 31 years old in 2013. The design, product of a national design competition, was created by renowned architect Michael Graves, with support from associate firm Emery Roth & Sons of New York. It was the first major Post-Modern expression to be fully realized and, as such, has been listed on the National Register of Historic Places as of “exceptional importance” despite not meeting the typical inclusion criteria of being more than 50 years old. The construction was also unique as being one of the first design-build arrangements in the country, involving a project management firm, two architects, two contractors, and a structural engineer. This has been well documented as having lead to communication problems, process issues, and change orders during construction that were not fully evaluated. The use of both the design competition for design and the design-build arrangement for construction were motivated by the City’s exceptionally low budget for the new building. Since completion, the building’s exterior envelope has presented numerous and chronic signs of compromise and failure of the exterior wall, resulting in water penetration, air infiltration, damage to interior finishes, mold, and the general discomfort of occupants. For exterior envelope issues alone, there have been multiple studies done in every decade of the thirty-two years since construction, starting as early as six years after construction. In that same time, there have been no less than nine major maintenance projects to address water infiltration. Structural studies have also been undertaken, and structural repairs completed, including a significant repair at the 15th floor in 1995. Despite the numerous individual studies and repairs,

• verarching system issues were never fully resolved. Seismic deficiencies initially discovered in

1995 were not deemed significant enough by the 1997 City Council to justify the costs of seismic upgrades. In 2010, Facilities initiated a new phase of repair, utilizing McBride Architects. This phase included replacement of the leaking membrane roofs at the 2nd and 3rd floor roof levels; replacement of the leaking membrane roof at the 14th floor roof level; and replacement of the leaking exterior envelope of the penthouse. It was determined at this time that additional phases would be necessary to address other ongoing envelope issues. FFA Architecture and Interiors, in partnership with The Façade Group and with KPFF Consulting Engineers, was contracted by OMF Facilities in September 2012 to provide the building’s first comprehensive assessment of existing exterior envelope conditions and building structural

• conditions. The contract provided for an assessment report, as well as repair and upgrade

recommendations, and project construction budget estimates. The full report and related deliverables were completed in March 2013 and are available for review. The report includes actual conditions, conceptual designs, and cost estimates. The Portland Building Exterior Envelope and Structural Improvements project aims to preserve a major asset of the City through rehabilitation of the failing exterior envelope. Seismic structural improvements will enable this critical asset to withstand a disaster, ensure quick recovery of standard City operations after a seismic event and preserve an expensive investment in the repair of the exterior envelope. The design team is under contract to proceed with design through construction documents and construction administration. The contract is on hold until Council reviews the proposed scope of work for construction. OMF Facilities is seeking direction on moving forward with the proposed scope of work.

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Condition Assessment The exterior envelope consists of seven primary assembly types: ceramic tile; ribbon windows; curtain wall; punched windows; storefront; concrete; and stucco. All seven assembly types had multiple failure issues. Of the seven types, the concrete and stucco are in the best condition. The other five assembly types demonstrate significant failures, leading to ongoing water infiltration, air infiltration, and damage to both exterior and interior materials. Ceramic Tile: The ceramic tile assembly occurs at the blue-green tile on all faces of the building at floors 1-3, as well as at red tile at the upper keystone (floors 11-15) on the east and west faces of the building. Types of deterioration include: cracked and etched tiles (throughout); corroding metal lath (critical in specific areas); efflorescence (major, causative of deterioration in

• ther assemblies, and indicative of chronic, significant water intrusion); deteriorated mortar

joints (major); ineffective re-pointing (major); exposed horizontal mortar joints (major); and deteriorated sealant and expansion joints (major, causative). The tile assembly was constructed as a direct applied system with no true drainage plane, and has unusually large grout joints (1/2” to almost 1”). Life span for grout is 5-10 years before re-pointing; previous re- pointing efforts, however, have failed due to complexities of original conditions. Without a drainage plane, water that gets behind the tiles has no (designed) way to get out. Efflorescence is an indication of water infiltrating into cementitious materials (grout joints, mortar setting bed, concrete slabs and walls), dissolving the salts in those materials, and, upon evaporation, depositing the salts on the surface of the tile assembly. Chronic and large-scale efflorescence indicates water intrusion has likely gone beyond just the grout joints and mortar setting bed, and into the concrete structure itself. Efflorescence deposits then etch the face of tiles, glass windows and aluminum window frames, creating further damage to the building. Although

• ngoing localized repairs may address some issues for a short amount of time, proper and

permanent repair of the ceramic tile assembly is not possible with the current assembly

• configuration. It is recommended to remove and replace the existing tile with a rain-screen type

assembly that allows for a drainage plane behind the setting bed. Ribbon Windows: The ribbon window assemblies occur as horizontal bands of windows between the red tile courses of the keystone (floors 11-15, east and west faces). The ribbon windows are a non-thermally broken, single pane, commercial “storefront” assembly, not intended for installation at this height because they are not designed to resist the wind and weather conditions that are encountered at higher elevations. Life expectancy of this system, when installed properly and in the proper application, is 30-40 years. Significant failure issues throughout the ribbon window assemblies include: failed glazing gaskets; failed perimeter sealant; failed expansion joint sealant; deteriorated finish; corroding window frames; inadequate and failed flashing detailing; corroding flashing fasteners; missing/deteriorated joinery seals; and loose fasteners. Water intrusion has been severe and persistent; in some areas, water regularly puddles on interior sills of offices, while interior vinyl wall coverings consistently peel away from damp wallboard. Due to the severe deterioration of the ribbon window assemblies and systemic nature of the deficiencies, localized repairs of these assemblies are not considered a viable

• ption. The solution is to remove and replace the ribbon window assembly with a new curtain

wall system fully flashed and integrated into the surrounding ceramic tile assembly. Curtain Wall: The curtain wall assemblies are on all four faces of the building, typically spanning from floor 4 to floor 10 as vertical bar elements interspaced with red-painted concrete “columns” in the building design. The curtain walls are a site-built aluminum system with non- thermally broken frames and single pane glazing. The assembly was designed as a barrier system; water was intended to never enter the system, so any water that does enter through

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system failures has no adequate drainage path to exit. Similar to the ribbon wall assembly, the curtain wall assembly shows the following significant failure issues: failed glazing gaskets; failed perimeter sealant; inadequate and failed flashing detailing; failed expansion joints; missing/deteriorated joinery seals; and deteriorated finish. Life expectancy of this system, if detailed, installed and maintained properly, would be 30-40 years. Several previous large-scale repairs have been made, with minimal success. Like the ribbon window assemblies, localized repairs of these assemblies are not considered a viable option. The solution is to remove and replace the ribbon window assembly with a new curtain wall system. Punched Windows: Punched window assemblies are found within the blue-green tile at the base of the building and within the beige-colored concrete walls on the upper floors. The punched windows were field assembled, non-thermally broken aluminum frames with single pane glazing. No head or sill flashings were designed or installed at these windows. Windows set into concrete openings have sloped sills and drip edges cast into the concrete at the head; windows set in the blue-green tile have neither. Life expectancy for these assemblies, if detailed, installed and maintained properly, would be 30-40 years. Again, these assemblies show: failed glazing gaskets; failed perimeter sealant; failed expansion joints; loose and gapping frame construction; missing/deteriorated joinery seals; and deteriorated finish. At a minimum, these assemblies require all new perimeter sealant joints, all new glazing gaskets, and sealing of all gaps in the frames. These localized repairs will address current damage, mitigate water infiltration and improve aesthetics over the short-term; they will not address

• verall system deficiencies or provide a long-term solution. The preferred solution is to replace

punched window assemblies with new curtain wall assemblies, fully flashed and integrated into the surrounding ceramic tile assembly. Storefront: The aluminum storefront assembly at retail spaces on the first floor (under the loggia as well as at the exterior wall on the north, east and south faces) is a non-thermally broken frame system with single pane glazing. Life expectancy, under best conditions, is 30-40

• years. Protected locations under the loggia are in fair condition, mostly showing wear of age

and having been modified by multiple tenants in the past. Locations exposed to weather, particularly at the daycare on the south east corner, show severe gasket failure. Similar to the punched windows, these assemblies require, at a minimum, all new perimeter sealant joints, all new glazing gaskets, and sealing of all gaps in the frames. These localized repairs will address current damage, mitigate water infiltration and improve aesthetics over the short-term; they will not address overall system deficiencies or provide a long-term solution. The preferred solution is to replace storefront assemblies with new storefront assemblies, fully flashed and integrated into the surrounding ceramic tile assembly. Concrete: The Poured in Place concrete is located on all faces of the building, covered in beige and red elastomeric paint coatings. The elastomeric coatings are the only waterproofing system for the exposed concrete, which also makes up the structure of the building at exterior

• walls. Elastomeric coatings should be replaced every 5-10 years. The concrete is in good

condition overall with some cracks and spalls that require patching. The elastomeric coatings appear to be mostly intact, but are due for re-coating. Repair solutions are to pressure-wash, patch, and re-coat. Stucco: The stucco assembly is found at the four column capitals on the east and west faces

• f the building (between floors 9 and 11), as well as the flat “ribbon” projection on the north and

south faces at the same floor levels. The stucco is applied over lightweight metal framing and painted with an elastomeric coating. These areas of applied ornamentation allow moisture to drain behind them. The condition is generally good with some minor cracks that require

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patching, as well as some missing joint sealants. Repair solutions are to pressure-wash, patch, install vertical joint sealant, and re-coat. Interior Construction Issues: The interior construction is light gauge metal stud framing,

• ffset about 1” from the interior of the concrete wall, with fiberglass batt insulation. Interior wall

finish is gypsum board, covered with painted vinyl wall covering. The vinyl wall covering was intended as a “warm side moisture barrier” to keep moisture from the heated interior from entering the wall cavity and settling as condensation on the cold concrete. This type of system needs to be constructed and maintained perfectly in order to keep moisture from penetrating the vinyl/gypsum assembly. Moisture that has inevitably entered the wall over the years has not been able to exit, leading to wet fiberglass insulation, peeling gypsum and vinyl, and mold

• spores. The wet insulation is no longer able to properly insulate interior spaces, leading to

decreased energy efficiency. In addition, the aluminum interior sills are in direct contact with the non-thermally broken aluminum window frames. This allows direct heat or cold transfer from the exterior air to the frame to the sill to the interior air. The aluminum sills can be 20 to 25 degrees hotter or colder than the room temperature. On January 17th, 2013, the outside air temperature was about 28 degrees, interior window frame temperature was about 38 degress, the sill temperature was 40 to 44 degrees, and the room temperature was about 68 degrees. This would be similar to sitting next to an open refrigerator. Structural Assessment To perform the structural assessment, KPFF reviewed available original construction documents and performed physical testing of existing structural elements. Concrete core samples in multiple locations on every floor were removed and tested to determine the concrete compressive strength. Reinforcing bar samples were also removed and tested to determine the rebar yield and ultimate strength. Ground Penetrating Radar (GPR) was performed to identify locations of steel reinforcement within concrete, in order to compare against original construction documents as well as correctly place core sample locations. The resulting information was analyzed for conformance to the 2010 Oregon Structural Specialty Code for gravity systems and to ASCE 41-06 Seismic Rehabilitation of Existing Buildings for lateral (seismic) systems. The horizontal elements of the building’s structural system consist of concrete waffle slabs with wide-shallow beams, within the waffle slab, located along column lines and adjacent to perimeter walls. Those horizontal elements are supported vertically by reinforced concrete columns on a 30’ x 30’ grid at the interior of the building, and reinforced concrete walls at both the central core and the exterior of the building. Testing determined the as-built concrete and reinforcing steel strengths were, in many cases, at

• r above their design strengths. The primary area of deficiency was the concrete at

slabs/joists/beams, where the average core strength was 13% less than design. Concrete walls (average 12% greater than design) and concrete columns (average 5% greater than design at floors 4 and above, average 60% greater than design at floors 3 and below) tested well. Analysis of the gravity system as a whole determined it was generally meeting code criteria, despite having some minor areas of weakness. The lateral (seismic) load system was designed as a moment frame consisting of the slab/beams transferring lateral loads to columns. The concrete exterior walls and interior core, however, also act as shear walls, taking lateral loads from the slab/beams. Based on review of existing documentation, it appears the design intent was for the moment frame to attract a significant portion of the seismic load. However, the size and stiffness of the concrete shear

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walls unintentionally dominate the seismic response of the building. Since the shear walls were not designed to carry that type of load capacity, they are significantly overstressed. Discontinuous shear walls below the third floor also create overstressed conditions at the columns supporting those floors. This creates critical seismic deficiencies at these conditions. In addition, the degradation or loss of these elements due to seismic load could lead to localized loss of gravity support in areas supported by these elements. Based on the deficiencies identified in the assessment, the existing building structure can be expected to perform poorly in a wide range of seismic events. In only a minor seismic event of relatively small magnitude, the building may experience some structural damage. This could include, but not be limited to, shear wall cracking that should be within repair. In a moderate level seismic event, the existing building may experience moderate to large levels of structural damage (i.e., shear wall cracking and crushing). These levels of damage could still be within the realm of repair, but they would also carry a substantial cost to do so. In a major, code-level seismic event, the existing building will likely experience significant structural damage throughout (i.e., significant shear wall cracking and crushing). The post-earthquake state of the building will likely be unusable and also beyond repair. It may also experience localized areas

• f lost gravity support. This is in contrast to a “current code” building that can be expected to

resist the same major level seismic event with some structural damage, and most likely all at a repairable level. Even though the existing building is expected to perform poorly in most seismic events, current jurisdictional requirements do not consider poor expected building performance as an upgrade

• trigger. Jurisdictional requirements involve modification to the hazard classification, occupancy

category, or the occupant load. The use and occupancy load of the existing building is not being modified; therefore none of those occupancy-related triggers are being tripped. As a result, a mandatory seismic upgrade is not required. Options There have been extensive, ongoing water intrusion issues in the Portland Building since

• construction. Despite numerous studies and major repair projects over the last three decades,

there has been no long-term resolution. The City has reached a critical juncture with regards to ensuring the continuity of core operations; providing for the health and safety of 1,500

• ccupants, and addressing the ongoing building issues. The practice of attempting to “patch”

maintain the building with $500,00-$1,500,000 projects every couple years has not been

• successful. This practice can no longer effectively maintain the building envelope and structure.

Money spent on these “patch” projects is wasted because this type of repair cannot provide a long-term solution. In addition, the continued water infiltration gradually degrades the underlying concrete structure of the building. There are, therefore, two primary options for addressing the issues. Each has been reviewed for strengths, weaknesses, and costs. The first option is to address the issues with the proposed project. This project would look to replace-in-kind entire material assemblies, where allowed by land use approval. Removal and replacement of damaged interior drywall and insulation at perimeter walls would be done in conjunction with exterior envelope work. While perimeter walls are exposed on the interior, seismic upgrades at those walls could be done most cost-effectively. The City Office Space Planning project would be fully integrated with this project. Bureau moves related to the space

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planning would be minimized prior to construction; tenant build-outs for the space plan would take place in the unoccupied building during construction on the exterior envelope; and most bureaus moving as part of the space plan would not move until after construction is complete. The benefits of this option are: City’s asset is preserved; City maintains ownership of 364,000 sf of office space for City operations; a building listed as nationally significant on the National Register of Historic Places is preserved; the City Office Space Plan is fully integrated; seismic is upgraded to meet code and the building will be able to withstand a major seismic event without collapse; time to get City operations back in place after a seismic event will be minimized;

• ccupants will have improved environmental health and safety; and major maintenance funds

are preserved for repairs and upgrades to interior building systems and finishes. There is a major upfront cost of estimated $95M; and all tenants will need to be moved to a temporary facility during construction, potentially causing some business disruptions. The second option is to vacate and/or demolish the Portland Building and buy or build a new

• structure. Depending on regulatory requirements (demolition permit subject to design review

due to National Register status) and market interest, the Portland Building would be vacated and either demolished, sold or abandoned in place until further options were available. A new structure would be built to City specifications to meet City occupancy needs. The Portland Building consists of 364,000 sf of leasable space, and currently has approximately 1,300 employee occupants. Costs of a new structure could vary significantly, depending on whether the City already owned a buildable site; where the building would be located in Portland; and the extent to which green technology and other modern building improvements would be

• incorporated. City Council Resolution 36700 in 2009 required that all new-construction City

buildings be certified as LEED Gold. A preliminary rough estimate for a new building ranges from $110M to $400M; if this option were chosen, use of an outside consultant for further assessment of costs would be necessary. The benefits of this option are: ongoing maintenance costs will be minimal for the first 10-15 years; the building will be built-to-suit, with desired green technology, current seismic requirements, and other current building improvements; and occupant environmental health and safety will be maximized. However, tenants will need to be moved to a temporary facility during construction, potentially causing some business disruptions; the length of time to vacate, buy or build new structure, and move in, is expected to be significantly longer than the first option; and there is no clear solution as to what to do with the existing historic building with its known issues. Recommendation OMF strongly recommends addressing the issues with the proposed Exterior Envelope Restoration and Structural Improvements. This project preserves a City asset, City-owned

• ffice space, and a nationally-significant historic building, while also maintaining environmental

safety and health of occupants, integrating cost-saving space planning measures, and preserving continuity of City operations after a seismic event. The long-term costs of ineffective “patch” repairs are considerable, especially in light of the ongoing effects of water infiltration on the concrete structure that supports the building. Due to the National Register listing and historic significance of the Portland Building, demolition by the City would be difficult to move

• forward. Construction of a new building is not only the most expensive option but also raises

questions of the City’s commitment to sustainability, historic preservation, and effective management of existing assets.

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Applicable City Policies/Audits The City Auditor released a Transition Report on July 11, 2013, with the following two major risk areas noted: City does not maintain all its major assets in good condition; and City services may not be adequately prepared to withstand a disaster. In the March 2013 Basic Emergency Operations Plan, the Portland Building is noted as an essential facility to City operations (page 24). City Policy ART-3.01 prioritizes the location of city offices and operations in historic buildings. Although the policy is intended to prioritize the use of historic buildings for city operations in a non-city controlled building when a city-controlled building is not available, it shows strong policy support for the preservation and use of historic structures. Financing Approach The City Office Space Planning project will be fully integrated into the financing for the Portland Building Exterior Envelope and Structural Improvements project, for a total estimated project cost of $95M. Project financing would be provided by a line of credit through construction to minimize annual costs during construction. Upon completion, 20-year Limited Tax Revenue Bonds would be sold to convert the line of credit to long-term financing. Annual debt service on the long-term bonds is approximately $8.05M, based on estimated interest rates. Please see the spreadsheet in the Financing Cost Estimate section for a breakdown of the rates by year by fund. Integration with Space Plan Cost savings and space efficiences can be best realized by fully integrating the City Office Space Plan into the Portland Building Exterior Envelope and Structural Improvements project. Bureau business disruption will be minimized by coordinating most space-planning related moves to occur after completion of construction of the exterior envelope and structural improvements. Prior to start of construction, the focus will be on space plan moves that allow the Revenue Bureau to move from its out-lease in Columbia Square to the 1900 Building 6th floor prior to the lease expiration date 5/31/15. PSSRP will move off the 1900 Building 3rd floor to TPB 12th floor. BTS will move off the 1900 Building 3rd floor to TPB 14th floor. BDS will then move onto the 1900 Building 3rd floor to free up the 1900 Building 6th floor for the Revenue Bureau. When construction is ready to start at the Portland Building, all occupants will move to temporary office space for the duration of construction. During construction, Revenue Bureau will move from Columbia Tower to the 1900 Building 6th floor. While construction is underway for the exterior envelope and structural improvements, tenant build-out will occur in the unoccupied TPB on floors 4, 7, 12, and 14 for upcoming space plan

• moves. When construction is completed, all existing TPB tenant bureaus as well as bureaus

slated for a Space Plan move will move to their final locations in TPB. Risk Management (previously TPB 7th floor) and Facilities Services (previously TPB 12th floor) will move to TPB 4th

• floor. Water Bureau (previously TPB 14th floor) will move to TPB 7th floor. EBS (previously TPB

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14th floor) will move to TPB 12th floor. BTS (previously TPB 4th floor) and OEHR (previously Commonwealth Building) will move to TPB 14th floor. BES (previously Pioneer Tower) will move to TPB 15th floor. PHB and FPD&R will move to City space currently in development. If delays occur during construction, lease extensions can be negotiated for temporary space for current TPB occupants, as well as the three remaining out-leased bureaus (PHB – Commonwealth Building existing lease through 10/31/16; BES – Pioneer Tower existing lease through 11/30/16; FPD&R – Harrison Building existing lease through 7/31/17). Challenges Facing This Project  Support from Historic Landmarks Commission and community for proposed envelope restoration details.  Financing for project.  Impacts of full building temporary relocation on any affected bureaus’ significant project rollouts.  Tight timelines to ensure full integration of construction with proposed moves by out-leased bureaus. Upcoming Council Packages  Budget decision package for FY14-15 and out-year financial forecasts.  Presentation to Council on the budget decision package as part of the FY 14-15 budget session.  If budget decision package is approved, an ordinance to move forward with bond financing will be presented in FY14-15. Next Steps Next Six Months: Advertise for CMGC and enter into contract for pre-construction services with CMGC (CMGC pre-construction services contract to be approved by Council via ordinance). Give direction to design team to initiate Schematic Design. Begin Land Use Review Design Advisory process. Begin search for temporary lease space for duration of construction. Next Year: Complete Phase I space plan moves. Review GMP and enter into contract with CMGC for construction services (CMGC construction services contract to be approved by Council via

• rdinance). Complete Phase II space plan moves. Complete construction documents. Begin

tenant bureau moves to temporary space. Next Three Years: Complete construction. Move Bureaus back to TPB. Convert line of credit to 20-year Limited Tax Revenue Bonds.