190131 Narrative - Arch - 100% (MAC) 3 phase.MAC

Design Narrative

PROJECT NAME: 6973GH-18-F-01245: LSF West Drive Modifications

SPUR PROJ. NO.: 1691.12

SUBJECT: 100% Submittal – Architectural and Civil Narrative DATE: October 18, 2018

Project Overview and Background

The proposal received from the Mike Monroney Aeronautical Center called for renovation (remodel) of the existing roadway, driveway, and drainage running along the west side of the LSF facility. The objective is to provide modernization all drivable and walkable surfaces in the area while also amending the site drainage problems.

Where walkways are within the scope of work and are not currently attached to the building, new accommodations will be made to bring surfaces up to current IBC building code and ADA / ANSI requirements.

Additionally, adjacent curbs, sidewalks, physical protection devices, storm water drains, and gravel beds will be replaced as required. Current fire hydrants and other fire protection equipment will be protected and left in place.

Architectural demolition work will be limited in scope as the majority of demolition will civil in nature. All areas will be designed under current applicable standards.

All areas will be designed using the latest standards and applicable codes and regulations within the local jurisdiction including IBC 2009. The goal of the project is to create an environment that fosters ease of use, comfort and safety for the employees and visitors utilizing the space.

Existing Conditions Assessment

The functionality of existing systems were evaluated on a site visit dated 05.14.2018. Investigative services were performed to establish scope and determine magnitude of issues. The following existing conditions assessment outlines observed conditions on the site.

During the initial site visit the AE team observed the condition of the existing concrete roadway. The majority of surfaces have worn significantly after several years of use. Frequent spalling and exposed aggregate can be found throughout the site. Cracking, patching, and chipping are also common. Asphalt parking area was later added to the west side of the drive for parking purposes. The joint between the concrete and asphalt has seen repeated temperature variation which has lead to some cracking. Pitting on the surface is common and wear patterns from vehicular parking are visible.

Gravel infill is present along the building in several areas and is the primary parking surface at the southwest corner of the facility between the drive and the exterior storage space. Gravel is additionally used in non-parking surfaces to presumably assist in water permeability. Site drainage was not visibly observed during the site visit, however evidence of water runoff and erosion is indicative of problems that are persistent throughout the site. Pooling in areas as well as water evacuation difficulties at storm water runoff drains is apparent. In some areas water erosion has eaten away at grade levels below sidewalks and other surfaces causing probable hazards. Debris blockage and lack of site drainage are likely causes for these difficulties.

A lack of pedestrian sidewalks is evident. In some locations where sidewalks were desired to be added an asphalt strip was poured. This surface seemingly does not meet width, slope, or smoothness requirements and recommendations. Existing ramps that are attached to the building were not evaluated as they are to remain and are out of scope. Extensive fixtures and equipment along the face of the building may cause difficulty in placing new sidewalks should they be desired.

Fire protection fixtures and physical barriers are scattered along the building exterior. Fire Hydrants and other items have been elevated as necessary. Bollards and parking stops have been placed in locations to protect these fixtures and building surfaces. Both bollards and stops have seen extensive use and damage. Bollards are frequently tilted due to impact and stops are also cracked or broken.

Southern portion of site looking north Storm water Runoff at SW corner of building

Erosion visible beneath sidewalk Asphalt parking on west of drive (typical)

Asphalt sidewalk along building, gravel parking Fire safety equipment and barriers

Gravel bed with shelter Existing Ramp and sidewalk at entry (to remain)

Northwest corner of facility, sidewalk to remain Northern extent of scope

Recommendations

With the efforts of our team we recommend the replacement of the driveway, parking surface, and supplementary items throughout the area. In addition to the replacement of the driveway surface it is strongly encouraged that site drainage issues be remedied. Additionally, existing sidewalks, pads, physical protection devices, and other equipment should be repaired or replaced as necessary to provide the best user experience and a cohesive appearance along the site.

Phasing

In order for operation of the LSF space to be used during the construction process a phasing plan has been developed. Phase 1 - Station 14+30 to Station 18+03.74: Demo existing roadway, Construct new work as designed. Contractor to provide access to south half of drive at Station 14+30 during construction.

Phase 2 - Station 2+17.85 and Station 14+30: Construct temporary drive at Station 1+75. Demo existing roadway.

Construct new work as designed. Contractor to provide access to north half of drive at Station 14+30 during construction. Phase 3 - Station 1+00 and Station 2+17.85: Remove temporary drive asphalt surface. Demo curved portion of existing drive. Construct new work as designed.

Grading

The proposed improvements will address the current drainage issues with the proposed pavement replacement constructed at a minimum grade of 0.40%. The proposed grading of the project will match the existing grades at the building face. Using the existing grade at the building as the control, the profile of the street will be lowered a maximum of 1 (one) foot in areas currently identified as low points Grading is anticipated to be minimal. Earthwork will use onsite materials to meet the grades required for construction and drainage. Satisfactory fill or modified existing materials will be used to grade the site to the proposed grades. The existing top soil will be stored on site and used to develop final grades.

The proposed grading will provide positive drainage away from buildings, roads, and parking areas. The proposed grades will maintain the existing storm flow patterns where possible and utilize existing drainage structures and inlets.

Pavements

Geotechnical investigation is being performed and a new pavement section is being developed. It is anticipated that due to the nature of the area and the potential for truck traffic, 8-inch concrete pavement on lime modified subgrade is being considered for the street portion and loading dock areas of the project. The parking areas adjacent to the building and parallel to the west side of the northern portion of the project is also being considered for 6-inch concrete pavement section. Both of these pavement sections utilize a 6-inch aggregate base as well as the compacted or modified subgrade.

As such, the attached site improvements include the removal and replacement of all existing pavement for the entire project. New pavement is expected to be dowel jointed P.C. concrete.

Proposed pavement is described below:

A S.W. 64th Street (Access Drive) – The proposed layout will utilize the existing street geometrics to define the centerline of the proposed improvements. The new street section will be approximately 31’ wide to match the existing pavement width. The street approach to MacArthur on the south end of the project will retain the existing flare to allow for large trucks to negotiate the exit without damaging the curb or edge of pavement.

B Parking –The site layout will incorporate improved and designated parking. The existing gravel parking area on the west side of the building will be replaced with a 6-inch dowel jointed P.C. concrete pavement on a treated sub-grade along with the existing designated parking spaces will be striped in these areas to define spaces and protect existing above ground facilities.

Site layout is such to ensure parking on the west side of the building begins an adequate distance from the western most edge of the building or above ground facilities, this will be achieved by providing a sodded grass area and a sidewalk alongside the building where practical.

C Pedestrian Circulation – A concrete pedestrian walkway (5ft wide) will be constructed to provide access along the building and the parking areas where practical. An ADA accessible route will provided to each of the west side entrances.

Storm Water Drainage

A Storm water drainage will be away from buildings and structures. Curb and gutter will be only used along the west parallel parking areas. Moveable curb stops will be used at the edge of the new pavement to restrict vehicles from leaving the pavement. This will allow the surface drainage to sheet flow to the storm water inlets. Existing storm sewer inlets were identified and incorporated as low-points along the project limits to maximize the effectiveness of the inlet. Two (2) new storm sewer inlets are incorporated and no significant changes to the existing system will be made.

Storm water design for this facility was recently upgraded and evaluated under a separate project. Due to the nature of this project maintaining a similar amount of paved surface area and no significant changes are made to the drainage basin, a design analysis was not performed for this project.

B Storm Water Drainage improvements will be designed as to maintain these flow patterns, however sheet flow across paved areas will be minimized. Slopes for paved areas will be 0.40% minimum and 6% maximum. Slopes for grass areas will be 0.5% minimum and 6% maximum. Grades at buildings will be 0.5’ below finished floor elevation and will slope away from the building.

Utilities

Existing water, sanitary sewer, gas, storm sewer, and fiber optics are located on site and currently serve the area.

All utilities were field located and documented as part of the original topographic survey. These lines are assumed to be clear of the existing facilities and are not anticipated to be impacted by the proposed improvements.

Each utility will be verified for the vertical location prior to construction or excavation in the area.

Turf and Landscaping Minimal landscaping shall be utilized to improve the visual appearance of the surrounding site and the building area. Landscaping is expected to be limited to seed and sod.