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Project NEONProject NEONProject NEONProject NEON

Aesthetics and Landscape Requirements Report

Section1: Section1: Section1: Section1: I I I Introductionntroductionntroductionntroduction August 2006 of XX

BBBB eginning in May of 2000, the State of Nevada through the State Transportation Board and the Nevada Department of Transportation began a planning process to create a vision for the state

highway system that would satisfy the need for landscape and aesthetic considerations throughout the state. It was recognized that the state highways present an opportunity to demonstrate the images, history, peoples and climate that make Nevada a unique and special place. This report, which documents the Project NEON Aesthetics and Landscape Requirements, is an out –growth of both that initial planning effort as well as the subsequent planning efforts that have been on-going since 2000. The purpose of this report is to serve as the Aesthetic Manual for the project. It is anticipated that the project will be built over a number of years and in a number of phases. The requirements outlines in this report will allow for the consistent application of the project aesthetics and landscape through each phases of the work. The use of the word “requirement’ in the report title signifies that these are not merely guidelines, but required elements must be considered on equal footing with all other project elements. The report is divided into four sections: Section 1 provides the background of the State’s past planning efforts and how they relate to the Project NEON aesthetics and landscape. The project specific requirements are also discussed. Finally, the process followed to develop the aesthetics is outlined. Section 2 presents the development of the project theme, beginning with the opportunities and constraints presented within the project corridor. Adjacent on-going and constructed projects that may influence the design are described. The selected theme is described in terms of the general expression in both the landscape and the structural aesthetics. Section 3 details the requirements for the structural aesthetics for all bridge and wall elements within the project, including:

• Bridge aesthetics for ramp, flyover, and local street bridges • Retaining walls • Sound walls • Public art elements • Decorative Lighting

Section 4 summarizes the proposed landscape aesthetics for the corridor, including:

• Groundplane concepts • Planting palettes • Tree planting locations • Shrub and bed plantings • Irrigation requirements

Finally, a series of appendices are included which describe the 2 concept alternatives not selected for the project, cost estimates for the proposed aesthetic improvements, cost estimates for the long term maintenance of the landscape, and additional background information.

“A vision for the State “A vision for the State “A vision for the State “A vision for the State

Highway System: We envision Highway System: We envision Highway System: We envision Highway System: We envision

a system of state highways that a system of state highways that a system of state highways that a system of state highways that

reflect the lanreflect the lanreflect the lanreflect the land and people of d and people of d and people of d and people of

Nevada. We believe that Nevada. We believe that Nevada. We believe that Nevada. We believe that

Nevada should have highways Nevada should have highways Nevada should have highways Nevada should have highways

that are aesthetically pleasing, that are aesthetically pleasing, that are aesthetically pleasing, that are aesthetically pleasing,

as well as safe and cost as well as safe and cost as well as safe and cost as well as safe and cost

effective. Therefore, no state effective. Therefore, no state effective. Therefore, no state effective. Therefore, no state

highway is complete until highway is complete until highway is complete until highway is complete until

landscape and aesthetics are landscape and aesthetics are landscape and aesthetics are landscape and aesthetics are

considered and addressed.”considered and addressed.”considered and addressed.”considered and addressed.”

-- NDOT, Pattern and Palette of Place: A Landscape and Aesthetics master Plan for the Nevada State Highway System.




Project Description & OverviewProject Description & OverviewProject Description & OverviewProject Description & Overview The Nevada Department of Transportation (NDOT) and the Federal Highway Administration (FHWA), in cooperation with the Regional Transportation Commission of Southern Nevada (RTC), and the City of Las Vegas are working together to coordinate the planning and design of the Interstate 15 (I-15) Corridor Improvements and Martin Luther King Boulevard (MLK)/Industrial Road Connector Project (referred to collectively as Project NEON).

The proposed project would involve improvements to the I-15 Corridor and major street connections beginning south of the I-15/Sahara Avenue Interchange and continuing to the I-15/US 95 Interchange (the Las Vegas Spaghetti Bowl) on the north end. The project covers a total distance of approximately 3.7 miles on I-15. Project NEON integrates six major highway improvement components, and these project components are shown in Figure 2:

• Expanding and improving the I-15 freeway mainline between Sahara Avenue and US 95

• Reconstructing the I-15/Charleston Boulevard interchange

• Adding I-15 freeway access ramps near Alta Drive for movements to and from the south

• Creating a new six-lane arterial roadway connection over I-15, Charleston Boulevard and the UPRR, by connecting MLK and Industrial Road

• Grade separating Oakey Boulevard/Wyoming Avenue and the Union Pacific Railroad tracks

PURPOSE OF THE PROJECT

I-15 is a north-south interstate route that links Las Vegas to California on the southwest and to Salt Lake City and beyond on the northeast. The United States Highway 95 (US-95) freeway crosses I-15 near downtown Las Vegas. The I-15 Corridor also serves the Las Vegas Valley as a transportation artery through central Las Vegas.

Population growth in the Las Vegas Valley, projected to be approximately 60 percent from 2003 to 2030, will increase traffic volumes and local commuter traffic passing through this corridor. This growth will place substantial demand on the I-15 Corridor and connections to US-95. The purpose of this project is to meet the short- and long-term transportation needs of the project area. Proposed improvements to the highway geometry and traffic operations would also enhance safety for the traveling public.

The proposed improvements would accomplish the following primary purposes:

• Improve interstate and regional traffic operations

• Improve safety of interstate facilities and adjacent arterials streets.

• Improve access to downtown Las Vegas and Resort Corridor

Project NEON Overview Map




1.21.21.21.2 Past Studies and ReferencesPast Studies and ReferencesPast Studies and ReferencesPast Studies and References

Pattern and Palette of Place: A landscape and Aesthetics Master Plan for the Nevada State Highway System, NDOT, July 2002: This Master Plan establishes the framework for developing the various Corridor studies. The overall goal of the report is to renew Nevada’s commitment to highway corridor landscape and aesthetics. The report outlines 3 steps to achieve the goal:

• Master planning is the first step towards creating highways that reflect the people and places of Nevada

• Corridor Planning is the second step towards achieving Nevada’s highway vision

• Project design is the third step leading towards construction of landscape and aesthetic improvements.

Project NEON and this report represent the third of these steps. Construction within the Project NEON corridor will represent the culmination of the work started in 2002. I-15 Landscape and Aesthetics Corridor Plan, NDOT, August 2005: Based on the framework established in the initial Pattern and Palette of Place Report, the I-15 Landscape and Aesthetics Corridor Plan describes a comprehensive and detailed vision for the aesthetics and landscape within the I-15 corridor from Primm on the California border to Mesquite on the Utah border, which includes the Project NEON corridor in Las Vegas. The Corridor Plan identifies major design themes and materials for the I-15 Corridor. It also recommends treatment levels (intensities) to different segments of the corridor. The Project NEON Corridor falls within the Segment identified as the Dynamic Desert Metropolis and is made up of two sub-corridor sections: The Flamboyant Resort Corridor and the Redevelopment Corridor. The Flamboyant Resort Corridor calls for aesthetics and landscape that are intense, edgy and over the top design while the Redevelopment Corridor looks to use the landscape and aesthetics to both unify and soften both the highway structures and the adjacent urban edges. The study also identifies Charleston Boulevard as an area to have enhanced pedestrian connections to link city districts and enhance redevelopment and urban in-fill. Specific design objectives for each sub-corridor are:

Flamboyant Resort: • Announce the entry to the Las Vegas strip and the

entertainment district • Establish a gesture that is dynamic and bold in its expression • Emphasize the importance of nighttime arrival

• Define at the major interchanges accessing the “Resort

Corridor”, the importance of the attraction as defined by intense, edgy, and over-the-top design, reconfirming the landmark status of this arrival.

Redevelopment: • Incorporate additional right-of-way into the corridor.

Landscape design should anticipate the interface edges that may result from redevelopment.

• Utilize a unified material and plant palette to connect and

simplify individual projects

• Use landscape composition to soften both highway structures and adjacent urban edges.

The different sub-corridors within the Dynamic Desert Metropolis (below) are tied to the urban fabric with the city




Further definition of the landscape and structural treatments within both sub-segments of the corridor delineate the intensity of the treatments to be used. In the case of the Project NEON area, the “softscape” treatments (landscape and groundplane treatments) should be regionally ornamental in the Flamboyant Resort portion and regionally adapted in the Redevelopment Section. Structural treatments include landmark and focal, respectively.

Specific design guidelines were also provided to guide the physical changes for the existing and new highway projects, with the intended result being a more cohesive highway corridor that is compatible and sensitive to its context. Relevant design guidelines for the portions of the I-15 corridor with Project NEON include: Project Design Process:

• Understand the design theme segment theme and select design components that interpret the theme.

• Understand the site context, including the surrounding

landscape, and conduct a comprehensive analysis.

• Visualize design concepts for highway improvements.

• Integrate landscape and aesthetics at the onset of planning, design and engineering of all highway projects

• Consider landscape and aesthetics costs along side baseline

costs Transportation Art:

• Create regionally appropriate, meaningful art.

• Ensure artwork expresses an excellence if craftsmanship, quality, truthfulness, and originality.

• Consider each art piece as part of a larger whole

• Ensure transportation art supports the landscape design

segment themes (for the Dynamic Desert Metropolis this includes travel/tourism, unique urban metropolis, entertainment culture, the Las Vegas Strip/Resort Corridor, Red Rock Canyon, Hoover Dam, and City of Lights).

• Engage local agencies and organizations in the planning

process. Color Palette Application:

• Use a uniform, consistent color palette for all highway structures.

• Ensure accent colors highlight structural aspects.

• Blend new rock cuts and/or soil with the surrounding

landscape.

• Use color composition on bridges to visually reinforce structural elements.

Bridges:

• Use consistent bridge design throughout corridor. • Use simple sub-structure and support features.

• Use visually light bridge rail structures.

• Consider fill embankment and approach rails as part of the

bridge design. If possible flatten slopes to 3H:1V.

• Use landscape or rock mulch to stabilize embankments.

• Select vandalism resistant finishes.

• Create a visual design unity among all existing and new structures.

Retaining Walls:

• Consider grading to minimize wall height, but avoid steep embankments by use of terrace grades and low walls.

• Provide landscape planting in front of wall to soften

appearance of wall.

• Visually anchor retaining walls to the earth, by turning ends into slopes where feasible.

• Select a simple design palette of material, pattern, color, and

texture.

• Visual design themes on walls should be appropriate in scale and subject for the highway segment.

Sound Walls/ Screen Walls:

• Consider grading to minimize wall height. Where feasible freestanding walls should not exceed 14 feet in height without a step in the wall plane.

• Provide landscape planting and setback space between the

vehicle recovery zone and the sound wall.

• Select a simple design palette of material, pattern, color, and texture.

• Visual design themes on walls should be appropriate in scale

and subject for the highway segment.

• Create visual breaks and interruptions to avoid monotony along walls.

• Separate walls from other highway structures and set back

from travel lanes, when practical.

Levels of Landscape Treatment

Softscape Types and Hardscape Types

• Defined by a hierarchy of treatment levels

• Used separately or in combination to establish design character within the

SOFTSCAPE TYPES AND TR

STRUCTURES AND HARDSCAPE TYPES AND TREATMENTS




Concrete Barriers and Guard Rails: • Stain concrete barriers to match segments base color. • Avoid bright, shiny steel appearance in visually sensitive areas.

Grading & Drainage:

• Avoid creating steep slopes; 3V:1H is the optimal steepness. • Create smooth transitions and revegetate slopes; place salvaged

topsoil on all cut/fill slopes.

• Create “artful” earthwork.

• Blend earthwork with existing slope conditions.

• Use naturalized channel design, infiltration methods, and water harvesting for plantings to the greatest extent feasible.

Irrigation:

• Select efficient and effective irrigation systems. • Provide appropriate supplemental irrigation for each type of

planting/revegetation.

• Manage high concentration of salts.

• Use natural and/or artificial products to collect, store, and release water for plant use.

Groundplane Treatments:

• Implement appropriate “ground treatment” softscape type. • Consider aesthetics and maintenance requirements when

selecting types of treatments.

• Coordinate ground treatments with surround landscape. Landscape Plantings – Regionally Adapted:

• Enhance welcome centers, gateways, and urban areas using the Regionally Adapted softscape type.

• Use regionally adapted plant species. For this category, the

Mojave plant palette and dry land plants from other regions,

such as the Sonoran region, are planted in greater densities, forming a layer of over story and understory plantings.

• Preserve healthy, mature trees and/or vegetation within the

right-of-way. Landscape Plantings -- Regionally Ornamental:

• Use the Regional Ornamental softscape to create cultural meaning and/or a landmark feature.

• Use regionally ornamental plant species including non-native,

ornamental planting species that accentuate the composition possibilities inherent in form and color.

• Use 1 gallon container stock for groundcovers and perennials, a

minimum 5 gallon container fro all shrubs and cacti, a minimum of 24 inch box trees, and palms with a 20 foot minimum brown trunk height.

• Preserve healthy, mature trees and/or vegetation within the

right-of-way. Las Vegas Downtown Centennial Plan, City of Las Vegas , June 2000: The City of Las Vegas celebrated the centennial of its founding in 2005. As part of the City’s planning effort leading up to the centennial, the city developed this plan as a component of the City’s new 2020 Master Plan. The purpose of this plan is to “establish fundamental planning, development, land use concepts, and urban design standards to guide redevelopment through the centennial and beyond”. The planning area for the Downtown Centennial Plan does not fully cover the Project NEON corridor, but does cover the east touchdown of the Martin Luther King Flyover and also borders the east side of the NEON corridor north of Charleston Boulevard . In discussions with the City staff, it was felt that this plan provided the best information on aesthetics and urban design for the corridor. The Centennial Plan was applicable to the corridor area due to the close proximity between the planning area and the project. With regard to streetscapes, the Centennial Plan establishes the following design standards:

• North-South Streets shall be designed thematically with palm trees as the primary landscape element (25 feet or greater in height, spaced 30 feet on-center, preferred, to 35 feet on-center, maximum). Shade trees may be provided alternately between palm trees to provide additional shade.

• East-West streets shall

be designed thematically with shade trees as the primary landscape element (36 inch boxed trees spaced 15 to 20 feet on-center, preferred; 24 inch box trees at 30 feet on-center spacing, maximum).

• Supporting landscape and streetscape improvements shall be

incorporated into the streetscape design, including decorative paving, lighting, and other landscape elements such as freestanding planters, planter boxes, and hanging baskets.

• Street lights and decorative pedestrian lights shall be

incorporated into any future streetscape improvement.

• Within the “Arts District” (centered on Charleston, east of I-15), the use of public art within the streetscape is encouraged.

In addition to the Centennial Plan, the City of Las Vegas has developed a number of urban design requirements as spelled out below: Urban Design Guidelines and Standards, City of Las Vegas Planning and Development, March 1997. Urban Design Guidelines and Standards: Landscape, Walls & buffer Standards, City of Las Vegas Planning and Development March 1977. Additional planting selection information can be found in: Trees for Tomorrow: Tree Selection and Care, a Southern Nevada Guide, High Desert Resource Conservation & Development, Inc., April 2005.

1.31.31.31.3 AestAestAestAesthetics and Landscape hetics and Landscape hetics and Landscape hetics and Landscape Plan Plan Plan Plan Development ProcessDevelopment ProcessDevelopment ProcessDevelopment Process




As part of the design development process, NDOT established a task force to develop the aesthetic design theme and preliminary aesthetic design plans for both structures and landscape. The task force was composed of NDOT and City of Las Vegas staff, Parsons Landscape Architects, Engineers and Public Involvement Specialist, and a team of Landscape Architects from J.W. Zunino. The task force began meeting in July of 2006 and is expected to complete their work by spring of 2007. The team developed three theme project themes and also refined each theme based on comments from the Task Force. The themes were then presented to the public at a Public Open House in January of 2007. At this meeting the public was able to provide input into the theme selection. The final selection will be made by the task force, based on the input given by the public. After the theme was selected the Task Force concentrated on developing this Aesthetics and Landscape Report for the project which detailed the proposed aesthetic treatments to specific locations and structures in the project. Because build out for the project will happen over several phases over a number of years, the report will serve as the “aesthetic bible” providing continuity to the various design efforts. A flow diagram of the process, below illustrates the steps of the process:



2.02.02.02.0 Project ThemeProject ThemeProject ThemeProject Theme August 2006Page 1 of XX

he project theme can be likened to a thread that is woven throughout the corridor, stringing together the disparate elements into a uniform and cohesive design. The inspiration for a project theme can come from a variety

of places – history, environment, peoples, and places – to name just a few. For Project NEON history, geology, environment, and native plants played a big factor in the final selected theme. As described in the previous section, three different concepts were developed for the project. The three concepts developed are presented here along with the concept that was selected by the Project NEON Aesthetics and Landscape Task Force to carry forward to preliminary and final design. The selection was based in large part on the comments provided by the community at a public meeting held ___________.

““““This plan illustraThis plan illustraThis plan illustraThis plan illustrates a tes a tes a tes a detailed vision for the detailed vision for the detailed vision for the detailed vision for the landscape and landscape and landscape and landscape and aesthetics of the Iaesthetics of the Iaesthetics of the Iaesthetics of the I----15 15 15 15 Corridor. This vision Corridor. This vision Corridor. This vision Corridor. This vision synthesizes historic, synthesizes historic, synthesizes historic, synthesizes historic, current, and future current, and future current, and future current, and future conditions into a conditions into a conditions into a conditions into a comprehensive guide to comprehensive guide to comprehensive guide to comprehensive guide to improve theimprove theimprove theimprove the visual visual visual visual appearance of Iappearance of Iappearance of Iappearance of I----15 …”15 …”15 …”15 …” -- NDOT, I-15 Landscape and Aesthetics Corridor Plan

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2.12.12.12.1 Project Site Analysis & Project Site Analysis & Project Site Analysis & Project Site Analysis & OpportunitiesOpportunitiesOpportunitiesOpportunities andandandand Constraints Constraints Constraints Constraints

The project corridor runs between the Spaghetti Bowl (I-15/US 95 Interchange) on the north to the Sahara Interchange on the south, a distance of approximately 3.7 miles. South of Sahara, there are some minor improvements planned that are mostly associated with lane striping. The I-15 corridor is raised through this portion of the City with the local streets crossing below the freeway (undercrossings). SITE ANALYSIS The Site Analysis for the project can be seen on the following page. The discussion that follows references this drawing. The Project NEON corridor runs between several distinct land uses within the City of Las Vegas, including residential, medical, industrial, retail, and civic. One identified district is the Arts District along the east side of the project, centered on Charleston Boulevard. Also along the east side of the project centered on Bonneville Avenue is a significant retail development anchored by the World Market and the Las Vegas Premium Outlet Mall. On the west side of the project, there is a residential area between Sahara Avenue and Charleston Blvd. and a medical district north of Charleston. Because the corridor is elevated and there are only limited existing sound walls, there currently are views out from the corridor with the adjacent city development in the foreground and the Red Rocks National Canyon Conservation area in the background. A large portion of the fore and mid-ground views are currently to industrial sites and warehouses, particularly in the southeast segment and northwest segments of the corridor.

Two projects area adjacent to the corridor and may influence the selection of a theme as well as the project design – the I-15/US 95 interchange (the Spaghetti Bowl) and the US 95 corridor northwest of the Spaghetti Bowl. Spaghetti Bowl Landscape: The Spaghetti Bowl is a freeway to freeway interchange with many ramps and connectors (hence the nickname). The landscape and aesthetics for the interchange were installed within the last several years. The landscape in particular has won an award for its use of native vegetation and sculptures. The landscape is a combination of native cactus and other desert species, dry creek beds, boulders and sculptures. The success of the project has generated excitement in the community – there is a proposed “Tortoise Walk” pedestrian path in the area being proposed. US 95 Structural Aesthetics: West of the Spaghetti Bowl, the US 95 improvements are currently under construction. So the most notable items are related to structural aesthetics, including sound wall

treatments, bridge architecture and bridge parapet treatments. The sound walls combine a vertical fractured fin texture with a south-western pattern

that is located in specific locations along the corridor. The majority of the wall has a buff color with the patterned areas having bold accent colors of orange and purple. Springs Preserve: Along the south side of US 95 around the Springs Preserve is an existing sound wall with stylized desert images of agave, water, and sun. As opposed to the southwestern images on the US 95 sound walls, these images are painted onto the wall. I-15/ Sahara Interchange: Located at the southern end of the project, the northeast quadrant of Sahara Interchange has been improved with palm tree plantings and a decorative retaining wall with mountain imagery. It is important to note that for the palm plantings to occur NDOT required a Maintenance Agreement, since the maintenance required of the palms was outside of the available NDOT maintenance budget.

View in the Project NEON Corridor along SB I-15, just north of the Charleston Boulevard exit.

View of the Spaghetti Bowl landscape; note the tortoise sculpture in the center of the picture.

Constructed sound walls along US 95 west of the Spaghetti Bowl.

US 95 parapet treatment.

Springs Preserve Wall.

NE Quadrant of Sahara Interchange




OPPORTUNITIES AND CONSTRAINTS The opportunities and constraints analysis looks at the corridor for issues that will need to be addressed (usually a constraint) as well as for opportunities presented by the project to enhance both the project aesthetics and reinforce the aesthetics of the community. For Project NEON, the opportunities and constraints were divided between structural aesthetics and landscape, since these two categories often

have different evaluation criteria. The opportunities and constraints identified for each can be seen below and on the following sheet. Structural Aesthetics: For on-corridor areas, the I-95, MLK, and Sahara Flyovers will be some of the most visually prominent structures since these cross over the interstate. Sound walls on the I-95 flyover and in the Loch Lomond area will also be visual elements to on-corridor travelers. Off-corridor, the retaining and sound walls will be

most noticeable to people/homes/businesses adjacent to the corridor. The bridges, where I-15 crosses over the local streets, will also be visually prominent to off-corridor travelers. Because of its location within the City, the Charleston crossing is one of the more important crossings and needs to be addressed as such. Addition specifics are detailed in the graphic below:




Landscape Aesthetics: The opportunities for the landscape areas emphasize the importance of the connections within the city at the local cross streets. The importance of views from the corridor is also identified, with the view from the new MLK flyover presenting an opportunity for new views currently not available. Potential landscape

enhancement areas are identified. These are particularly associated with the local crossing points with additional areas along the west edge of the project. NDOT has very limited resources available for routine plant

maintenance, so for the landscape plantings to be included in the design, it will be important to reach an intergovernmental maintenance agreement with either the city or some public/private partnership. An agreement would allow for a more thorough approach to the landscape plantings.




2.22.22.22.2 ConceptualConceptualConceptualConceptual Project ThemesProject ThemesProject ThemesProject Themes Three conceptual themes were developed for the corridor; each relating to different aspects of the corridor history and environment. The three conceptual themes are:

• The Vibrant Desert • Meadows Redux • Corridor of Light and Shadow

Each of these is described in detail on the following pages: THE VIBRANT DESERT This theme uses both the landscape and structural elements of the project to celebrate the desert environment of Las Vegas. Beginning at the Spaghetti Bowl, the project will match the existing feel created by the landscape and sculptures found there. As the design moves south, the plantings and structural elements will become more elaborate with plantings changing from an informal layout to a more formal approach while the structures become increasingly detailed and may include decorative lighting.

Base landscape will include rock/gravel treatments to the groundplane, mounding, boulders, plantings and possible sculptural elements. Subsequent layers will increase the intensity and density of the

treatments. Color will also increase in intensity – becoming more vibrant farther south one is in the project. At the south-most end, palms may be included; if a maintenance agreement can be reached. Baseline for the wall structures will include indigenous images as a “wall paper” treatment. Bridges will be described in basic bridge architecture – including columns, pier caps, parapets, abutment, wing and retaining walls. Subsequent layers will add elements and highlight important bridges or structures for the NEON image. MEADOWS REDUX Meadows Redux seeks to bring back to the center of Las Vegas the meadow imagery the city was named for. This is seen as a primarily landscape driven theme with the structures, walls in particular, supporting the landscape images. Grasses and grass-like plantings will be the backbone plantings in the landscape and on structures. Traveling the corridor from the north to the south, one would encounter the desert landscape and images of the Spaghetti Bowl. These would quickly transition to the meadow/grassland images of the NEON Corridor. The farther south one is in the corridor, the “wetter” the grassland imagery appears until you reach the oasis with palm plantings found at the Sahara Interchange.

Structures will support the landscape with images of grasses and meadows as wall treatments, like those shown in the lower right. Bridge architecture will have strong forms, particularly of columns and

abutment/wing wall treatments. Fences and railings associated with the structures can echo the grass patterns. At the oasis, lighting accents may also be added to the structures. CORRIDOR OF LIGHT AND SHADOW The Corridor of Light and Shadow theme relies primarily on structural and vertical sculptural elements to communicate the theme. Plantings along the corridor are limited and used to support the theme with plants having vertical interest and a structural type image. The groundplane in this concept is highly sculpted and it’s coverings, whether plantings or gravel, are used to create the image of light and shadow. The intent of this design theme is to increase the intensity of the design the further south one is in the corridor.

Structural elements, particularly walls, also play with light and shadow. Sound walls may include colored Lexan inserts. Sculptural plantings, such as the larger prickly-pear cactus, may be placed against the wall to create shadow patterns. Bridge architecture would play an important role in the development of the design. The architecture should be simple, bold, and sculptural. Lighting is an important addition to the structural elements. Vertical sculptural elements will be an important addition to the landscape. These may be simple columns or other pre-cast elements or more complex art installations. It may be possible to work with the community to have various groups develop these sculptural elements under the oversight of a project resident artist.




2.22.22.22.2 CCCConceptual onceptual onceptual onceptual Applications of ThemesApplications of ThemesApplications of ThemesApplications of Themes Both the basic bridge architecture as well as the baseline landscape intent has been established by NDOT through its I-15 Landscape and Aesthetics Corridor Plan. With regard to the structural elements the Corridor Plan includes vertical or battered abutments; 3:1 slopes under and adjacent to bridges to avoid needing slope paving; simple substructure elements including simple geometric shapes for columns and box girders where feasible; employing shadows to barrier rails to reduce the visual affect; and color selections to be used.

For the purposes of all of these bridge aesthetic concept designs presented here, it was assumed that bridges would most likely have a box girder, although steel girders may be used in some instances, such as flyover bridges. Abutments were assumed to be full height given the tightness of the corridor which leaves little room for slopes. All bridges would require a concrete parapet matching the roadway barrier. On bridges where the local City street crosses over either over the railroad or the interstate, as happens for on both Wyoming and Martin Luther King Jr. Boulevard, fencing is required on the parapet. The combined height of the fence and parapet is ten feet.

In all three concept themes it was assumed that there would be three bridge categories. The categories are based on both the visibility of the bridge and its location and function in the corridor. The three bridge categories are:

• Ramp Bridges: This is the most common bridge type and also

the simplest in design. It is intended for bridges located on ramps where on/off ramps cross each other. For these bridges the design treatments include abutment wall jointing patterns, simple bridge pilasters, retaining walls, parapet design, and color treatments.

• Street Crossing Bridges: These bridges include those where

the Interstate crosses over the local streets. In addition to the elements included for ramp bridges, the Street Crossing Bridges also include bridge monuments on top of the bridge pilasters as signature elements.

• City Street Bridges: These bridges have the highest level of

treatments, in part due to their slower traffic speeds, their high visibility within the corridor, and the requirements associated with the potential for pedestrian traffic on the bridge. In addition to the elements included in the first 2 bridge categories, the City Street Bridge also includes parapet fencing.

For sound and retaining walls, the need for textures integral to the wall is identified along the ideas for the incorporation of landscaping and reducing the visual height of the walls. Sound walls were assumed to be a post and panel design, given the cost effectiveness of that construction type, except where the walls were located on roadside barrier where a sandwich panel type was assumed. For either type the development of graphic and formliner would essentially be the same. One advantage to this type of construction is that it is possible to cast the panels with an image on each side. Then by controlling certain elevations of pattern placement so that strong horizontal lines are an equal distance down from the top of the panel, the panels can be randomly placed while maintaining a consistent visual line. The net effect of this is that no two stretches of wall need appear the same preventing a monotonous appearing wall.

Retaining walls were assumed to be mechanically stabilized earth (MSE), since this is usually the most cost effective type of wall and also the most limiting in the development of aesthetics. An additional assumption is that the panels will be rectangular and measure 5 feet by 10 feet. This is a typical panel size, and allows for flexibility in the pattern as opposed to what is achievable with octagonal or cruciform panel shapes. Any wall graphics developed for MSE walls can also be

easily modified for full height panels or other wall types that might be eventually used.

The intent for the landscape design is also addressed in the Corridor Plan by outlining a recommended plant palette, guidelines for the arrangement of plant material, and groundplane treatments. Assumptions made with regard to the landscape are that within the I-15 NDOT right-of-way, plantings needed to be very limited due to maintenance concerns. The design in these areas should rely heavily on the use of rock mulch patterns and other “hardscape” groundplane treatments. Areas along the local streets and at interchanges provide, it was assumed, greater opportunity for plantings, should a maintenance agreement could be developed though either an intergovernmental agreement or a public/private partnership.

In addition to baseline landscaping, an enhanced level was also developed. This included additional plantings along the local streets and at interchanges. Additional elements, such as art/sculptures were also included at the enhanced level. Because the majority of the “landscape” areas along I-15 are very narrow, rockscaping will be the primary treatment along the interstate in all themes. What will differ is the type and color of the rock, along with the unique patterns and textures created to establish an image that supports each design theme. The Conceptual Application for each theme, along with an explanation of the design intent is detailed on the following pages:

THE VIBRANT DESERT

The Vibrant Desert concept seeks to celebrate the desert environment of the Las Vegas area by incorporating desert themes and images into both the structural aesthetics as well as the landscape in the NEON corridor. The influence of the desert on the image of Las Vegas is an influence that has not always been appreciated. However, the desert does present its own beauty and majesty that lends itself well to the aesthetics possibilities found in the Project NEON Corridor. Beginning at the Spaghetti Bowl, the project will match the existing feel created by the landscape and sculptures found there. The intent of the concept is that as the design moves south, the plantings and structural elements become more elaborate, increasing in intensity, density, and the vibrancy of the color (particularly with regard to plantings).

Bridge rendering from the I-15 Corridor Plan showing the vertical abutment walls, slopes, and landscaping.




VIBRANT DESERT THEME APPLICATION FOR BRIDGE ELEMENTS




VIBRANT DESERT THEME APPLICATION FOR BRIDGE DESIGNS



2.02.02.02.0 Project ThemeProject ThemeProject ThemeProject Theme August 2006

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VIBRANT DESERT THEME APPLICATION FOR WALL TREATMENTS




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Structural Aesthetics: For the Vibrant Desert Concept, images and textures were developed based on the desert ecosystem of the Las Vegas area. The structural aesthetics for this concept included:

•••• Bridge Girders: The preferable girder style of the bridges

would be a box girder style since this matches the style of the majority of existing bridges. If due to cost or construction issues this girder type is not feasible, steel ‘I’ girders would be the next acceptable alternative. However, with this girder, the girder depth should be kept consistent for the length of the bridge, rather than vary by span length. If variable girder depths are the only feasible possibility for the bridge, transitional sections must be included to allow the girder depth to visual “flow” between the deeper and shallower sections. Concrete “I” or bulb-‘T’ girders are the least acceptable girder type due to their infrequent use in the I-15 corridor.

•••• Bridge Columns: Proposed column shape is a round column

with bands of rustication (textures) near the top of the column. The round shape is a more organic form and so is appropriate to a theme based on an ecosystem.

•••• Bridge Abutments: The vertical bridge abutments would be

horizontally scored with wide joints (approximately 1-1/2” wide) at 2.5 foot centers. Some vertical scoring would also be incorporated in areas under the bridge. These would be associated with the required joints, but would be placed to enhance the design by being associated with visual cues such as corners on the box girders.

•••• Bridge Parapet: A geometric pattern, similar to what is being

constructed on the US-95 bridges is proposed for the areas either adjacent to the abutments or at the piers. Cross street identification signage (i.e. the name of the street on the bridge) and decorative building buttons would complete the design for both the Cross Street and City Street categories of bridges.

•••• Bridge Parapet Fencing: The design of the fencing is a

simple 2 inch by 2 inch powder coated mesh. The visual lightness of the fence will allow views out from the roadway. Associated with the fence are intermediate concrete pilasters that would be located at approximately 50 feet on center. The pilasters would include a formliner pattern that matches the one used on the retaining walls.

•••• Bridge Pilasters: A pilaster, set back from the abutment wall

and at the touchdown/takeoff points, would be placed on each of the bridge types. This pilaster would mimic the rustication/jointing pattern of the abutment wall and would have at its top a formliner insert depicting a desert image such as an agave, prickly pear cactus, snake, or cactus flower. These would not be visible to the on bridge travelers since they sit at the height of the bridge parapet/roadside barrier but would to travelers crossing under the bridge.

•••• Bridge Monuments: Large scale monuments would be

located on the Street Crossing and City Street bridges. These would be placed on top of the bridge pilaster and would include decorative lighting and street identification signage for the bridge users (to know what street they are crossing). The form of the monument is based on an obelisk, which is a classic form associated with the desert, but creates a more modern interpretation.

•••• Retaining Walls: A custom formliner would be developed for

the retaining walls, based on the Creosote Bush flower. The creosote bush is ubiquitous desert plant in the region. Because the bush is so common, the flowers brief in their existence, and because they are usually in bloom when other more showy plants are also flowering, the Creosote Bush is not always appreciated for its beauty.

•••• Sound Walls: The sound wall images for the corridor is

created using desert images with a mountain backdrop. Prickly pear, agave and barrel cactus dominate the foreground with different patterns and textures in the mid-ground depicting the rolling valley below the mountains.

Landscape Aesthetics: The “Desert” portion of the theme allows the landscape design to utilize many of the same treatments that were so successfully included in the Spaghetti Bowl landscape – cactus, rockscapes, and sculpture – while the “vibrant” portion of the theme allows for the landscape intensity to be increased over that of the Spaghetti Bowl. This is especially true the farther south one is in the project corridor.

Desert plantings, primarily at interchange ramps and adjacent to city streets, were informally placed to create a desert appearance that

shows both the richness and the beauty of the desert environment. This design aesthetic includes both natives as well as adapted species that would thrive with minimal maintenance.

Groundplane treatments of rock/gravel to create patterns and textures similar to those found in the Spaghetti Bowl will be used along the corridor, both along the Interstate and in the “off-corridor” areas where the plantings are located. MEADOWS REDUX

This basis of this concept is the historic meadows for which Las Vegas was named. The theme is primarily grass driven with grass and grass-like plants used in the landscape and grass like patterns and textures demonstrated on the structures. Using the Spaghetti Bowl as a starting off point, the landscape and structures quickly transition form desert cacti to desert grasslands. The farther south one is in the corridor, the more lush and dense would be the grass images.

Structural Aesthetics: Images and textures were developed based on bygone desert grassland ecosystem of the Las Vegas basin. The structural aesthetics for this concept included:

•••• Bridge Girders: Girder types for the Meadows Redux concept

are the same as discussed under the Vibrant Desert Concept. •••• Bridge Columns: The proposed shape of bridge columns is

rectangular so to allow for a “display” space on the column to include texture and rustication strips depicting a flowing grass image. For flyover bridges, the larger size of the columns allows for a larger image that encompasses a large portion of the column. On bridges smaller, multi-column bents, only the 2 outside faces of the outer most columns would receive the image.

•••• Bridge Abutments: Bridge abutments would be kept very

simple under this theme with few and less emphasized joints than in the previous concept. This serves to de-emphasize the abutment area and allows the viewers eye to be drawn to the other, more decorated, elements of the bridge.

•••• Bridge Parapet: The parapet would be treated with a custom

formliner pattern that would provide the image of the tips of the blades of grass.




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MEADOWS REDUX THEME APPLICATION FOR BRIDGE ELEMENTS




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MEADOWS REDUX THEME APPLICATION FOR BRIDGE DESIGNS




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MEADOWS REDUX THEME APPLICATION FOR WALL TREATMENTS




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•••• Bridge Parapet Fencing: Fencing for the parapet uses a

curved tubular steel to mimic a blade of grass. With this alternative, intermediate pilasters would not be used so that the pattern created by the fencing stretches continuously across the bridge. This has the visual effect of elongating the bridge, making it appear as a lighter structure.

•••• Bridge Pilasters: A pilaster, set back from the abutment wall

would be placed on each of the bridge types. These would be located at the touchdown/takeoff points for each bridge. The pilasters would have a similar graphic to the one proposed for the columns.

•••• Bridge Monuments: Monuments for the bridge, located on top of the bridge pilaster for both the Street Crossing and City Street Bridges. On top of the monument a sculpture, similar to the Desert Tortoise in the Spaghetti Bowl landscape would be placed. In addition to creating a whimsical addition to the corridor, the tortoise sculptures also reinforce the concept of a proposed “Tortoise Walk” being contemplated by the City of Las Vegas within the NEON Corridor area.

•••• Retaining Walls: In this concept, the corridor retaining walls

provide the real canvas for depicting the grass image. Through creative application of formliner textures, an image of a field of grass waving in the breeze is created. To achieve this two different panel types would be developed to create an image of the “body” of the grass and one for the “tops”.

•••• Sound Walls: For the Meadows concept, a different wall type

is proposed – a block wall. The primary advantage to using this wall type is to allow for a curved wall. This concept would relocate one of the primary sound walls, in the area of Loch Lomond Way, away from the edge of the proposed roadway into land that is being purchased for the project. Not all of this land is necessary for the final configuration of the roadway and other elements and to place the sound wall in this area would require additional fill since the wall will still be required to maintain the same height in relation to the road. However, the advantage is that it allows for landscape and groundplane treatments to be visible to the interstate, and the softer curving forms of the sound wall are more in keeping with the concept. In other locations within the project, the

proposed sound walls would still be located adjacent to the roadway because of tight ROW.

At approximately 75-foot centers, a pilaster would be located to break up the expanse of sound wall. The proposed pilaster would create a virtual “window” showing a mountain backdrop with rolling plains in the mid-ground and blades of grasses in the foreground.

Landscape Aesthetics: The proposed landscape plantings for this concept would use grasses and grass-like plants to carry the theme. They would be primarily used in the “off-corridor” areas along the local streets and at interchange ramps. Plantings in the “on-corridor” areas would be limited to trees and with a few areas of plantings of the grass-like plants that would not require regular maintenance. However, since the available area along the corridor is limited, the majority of the plantings would be found off-corridor.

Groundplane treatments include gravel mulches and rockwork. Dry stream beds with river cobbles and rounded boulders would also be used. Where feasible, berms and rounded land forms would be sculpted into the land and the possibility for water harvesting would be explored. CORRIDOR OF LIGHT AND SHADOW:

The desert is an environment of stark beauty and the quality of the desert light – the intensity of the sun, the blueness of the sky, the starkness of the rocks and geology – is one of its defining characteristics. The theme of “Corridor of Light and Shadow” gets its inspiration from the very quality of light found in the Las Vegas region. To achieve this, the corridor designs for this theme primarily rely on structural and vertical sculptural elements. Plantings along the corridor are limited to those with vertical interest or with a sculptural quality. Structural Aesthetics: For this theme, structural elements, particularly those that form the support structures take on a more civic/architectural character. This contracts with the more artistic and representations found in the “add-on” elements, such as bridge monuments and fencing. These elements begin to pull in the aspects of the desert geology within the context of light and shadow. The specific treatments for the structural elements include:

• Bridge Girders: Girder types for the Corridor of Light and Shadow concept are the same as discussed under the Vibrant Desert Concept.

• Bridge Columns: An elongated octagonal form is proposed

for the column shape in this concept. Visible score joints, occurring in a repeating pattern, break up the image of the column while providing a rhythm to the design.

• Bridge Abutments: Similar to the columns, the abutment

walls have the same repeating pattern of score joints which serve to break up the visual image of the wall while providing a stable and solid image to the wall.

• Bridge Parapet: The parapet uses a series of formliner

patterns to create a geologic image on the back of the parapet. Mountains, hills and rolling plains can be seen, but the imagery is subtle. The formliners would create different depths and therefore different shadow patterns to help carry the theme.

• Bridge Parapet Fencing: The proposed fence with this

alternative is a simple tubular steel fence with pickets to emphasize the vertical. At each pier, special panels made of 3” by 3” mesh with sculptural inserts of corten and stainless steel, used to create the geologic imagery, would be placed.

• Bridge Pilasters: Simple bridge pilasters with either a worked

stone formliner insert or, if budget allows, a man-made stone veneer would be place on all bridges.

• Bridge Monuments: Monuments proposed for the Street

Crossing and City Street bridges are very sculptural. They would be constructed from corten and stainless steel, have an appearance that emphasizes the vertical. Accent lighting could be placed along the guy wires to add additional night interest.

• Retaining Walls: In keeping with the simple starkness of the

theme, the retaining walls would use a deep (min. 1 inch) fractured fin texture. This would not only be consistent with existing walls along I-15 outside of the corridor, the texture would along provide variability in light and shadow on the wall.




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CORRIDOR OF LIGHT AND SHADOW THEME APPLICATION FOR BRIDGE ELEMENTS




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CORRIDOR OF LIGHT AND SHADOW THEME APPLICATION FOR BRIDGE DESIGNS




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CORRIDOR OF LIGHT AND SHADOW THEME APPLICATION FOR WALL TREATMENTS




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• Sound Walls: The proposed sound walls incorporate elements

of geology along with a variation of the southwest design found in the nearby US-95 corridor sound walls. A background image, simplified but similar to the bridge parapet design, would provide images of geology. Overlaying this are the man-made constructs of the zig-zag southwestern pattern. The pattern areas would be recessed and colored to provide accent and interest. In addition, circle areas with in the pattern would be filled with colored, transparent lexan. The lexan inserts provide an entirely different quality of light in the wall that usually found in solid walls.

Landscape Aesthetics: As opposed to the more naturalistic approaches to the landscape design in the previous two themes, for the Corridor of Light and Shadow, the landscape and groundplane treatments take on a decidedly more architectural appearance. Plantings are placed in grids and these are reinforced with the placement of large boulders set on the ground in a more artificial appearance. Vertical sculptural elements are included, especially at ramp/cross street intersections.

The groundplane is highly sculptural and this is reinforced by the placement of rock and gravel to create the appearance of positive and negative space.

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