B08_Attachment_6_GERO_289951_POR.pdf

REHABILITATE LINCOLN MEMORIAL BRIDGE

GEORGE ROGERS CLARK NATIONAL

HISTORICAL PARK

GERO

PMIS NO. 289951

PROGRAM OF REQUIREMENTS (POR)

FINAL REPORT

NATIONAL PARK SERVICE

DENVER SERVICE CENTER

JANUARY 18, 2024

PROGRAM OF REQUIREMENTS (POR) REPORT 2

Table of Contents Executive Summary

Project Location and Significance

Project Need

Program of Requirements (POR) Report Description

General Description of Design-Build (DB) Project Scope

Project Coordination

Structural Report

Introduction

Project History

Granite Clad Walls & Piers

Granite Stairs & Pavers

Exposed Concrete Aggregate Sidewalks

Framed Concrete Structure

Structural Design Guidelines: Applicable Codes & Standards

Structural Design Guidelines: Structural Loads

Structural Material Specifications: Concrete

Structural Material Specifications: Steel

Structural Material Specifications: Masonry

Structural Repair Options: Non-Stone Elements

Structural Repair Options: Stone Elements

Conservation Report

Overview of Existing Conditions

Repair Recommendations

Civil Report

Applicable Codes and Standards

Overview of Existing Conditions (Findings)

Civil Construction Work

Stormwater Management Requirements

Landscape Architecture Report

Landscape Architecture Scope

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Executive Summary

Project Location and Significance George Rogers Clark National Historical Park is located within the city limits of Vincennes, Indiana, adjacent to the Wabash River. The 26.17-acre site contains the George Rogers Clark Memorial that commemorates the achievements of Lieutenant Colonel George Rogers Clark and his frontiersmen during the American Revolution.

The park’s Memorial Era (1927 to 1936) reflects the period extending from initial conceptual design through subsequent design development, construction, and installation of the memorial (completed in 1933), to its dedication in 1936 (National Register of Historic Places registration form, 2013).

The Lincoln Memorial Bridge, completed in 1932, was designed as an important commemorative element contributing to the overall memorial landscape. The bridge continues to provide a dramatic and panoramic approach across the Wabash River to the memorial grounds. Important features of the bridge approach include the north and south plazas and the pylons of carved granite depicting two American Indians. On the south plaza, facing the memorial, are three inscribed panels highlighting the importance of this site and the Wabash River.

The design for the Park’s commemorative landscape reflected Beaux Arts aesthetic principles including the symmetrical arrangement of the grounds along a primary axial alignment extending from downtown Vincennes to the memorial building. Terraces, sculptures, plantings, green spaces, plazas, and broad vistas were all used to unify and accentuate the site’s formal classical character, with the memorial building serving as the centerpiece of the site design. The Lincoln Memorial Bridge was also designed as an integral element of the memorial, providing a grand approach to the site from the north.

Project Need The Lincoln Memorial Bridge approach is a concrete and brick substructure faced with decorative granite stones. The bridge approach has experienced issues with staining and deterioration of the decorative granite stones since shortly after its original construction. Water infiltration has compromised the anchoring system holding the granite stones in place, as well as the brick backing walls. Deterioration of the iron anchors was first noted in a state report from 1939. In recent years, many of the granite stones were observed to have shifted from their original positions and one stone became detached and fell. Destabilization of the granite cladding and the potential for falling stones was recognized as a serious safety concern, necessitating closure of portions of the bridge approach.

In addition, the granite steps, plaza paving, and connecting sidewalks have moved and shifted. An OSHA citation for an unsafe walking surface was issued in 2017. In June 2019, park staff worked with OSHA to design a plan to ensure employee and visitor safety around the bridge approach. Access to the flag plaza, steps, and stone walls of the approach were flagged and roped off due to unsafe walking surfaces.

The OSHA citation noted the need for a long-term solution.

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In 2023, removal of the granite cladding from the entire bridge approach was completed, in order to preclude additional stones becoming dislodged and falling. Concurrently with the stone removal process, a Predesign (PD) project was undertaken to assess and document the rehabilitation of the bridge approach. As part of the granite removal, much of the brick substrate was also dismantled because the brick and granite were constructed as one integral masonry coursing pattern.

At the time of this report, the granite cladding stones from the bridge approach are dismantled and stored in a park-owned temporary storage yard, awaiting rehabilitation. The bridge itself is a state highway and remains open to traffic while no active construction is underway. There is urgency to complete the rehabilitation process because the visitor portions of the bridge approach are closed, and because dismantling the bridge approach has exposed the bridge substructure to the elements which may contribute to further deterioration.

Program of Requirements (POR) Report Description The purpose of this POR Report is to communicate the bridge rehabilitation project requirements to prospective Design-Build entities to facilitate development of thorough and accurate Design-Build proposals. The POR Report has been prepared by the design team that completed the Predesign (PD) portion of the bridge rehabilitation effort, and includes assessment data gathered during PD as well as during the stone removal project conducted by others. Documentation included in this report and its appendices consists of:

• POR Report o Narrative description of project scope, description, assessments, and findings

Structural Report Conservation Report Civil Report Landscape Report

• Appendices o Site Topographic Survey o Site plans delineating project scope and limits o Division 1 Specifications o Divisions 2-49 Performance Specifications o Permitting Assessment Form (PAF) o Historic bridge approach blueprints o 2023 Stone removal drawings o Concrete Testing Report o Stone Cleaning Test Report o 2022 Bridge Inspection Test Report

• Data Files Available Upon Request o Three-dimensional modeling, point clouds, and ortho images of the bridge approach prior to removal of most of the stone cladding

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General Description of Design-Build (DB) Project Scope The bridge design-build project includes Design Development (DD) Documents, Construction Documents (CD), Construction, and As-Constructed Drawings as outlined in the RFP. The following paragraphs summarize the design-build scope of work.

This project will restore the bridge approach to the Lincoln Memorial Bridge and its associated features, to include the underlying structural elements and the exterior elements such as walls, landings, ornamental pillars, flag plaza, staircases, landscape beds, railings, and sidewalks, and improve safety for visitors and employees while preserving the historic resource.

The bridge approach, engraved pylons, viewing terrace and flag plaza are a concrete and brick substructure with decorative granite facing and paving stones. Water infiltration has caused deterioration of the underlying masonry walls, stone anchors, and paving systems, destabilizing the granite stones. Prior to this project, these granite stones have been removed and relocated to a temporary storage location near George Rogers Clark National Historical Park, not on NPS property.

This project will include the removal of the remaining portions of deteriorated brick substructure, cleaning and repairing the granite stones, restoring and/or replacing the underlying structure of the bridge approach and all related elements, and reinstalling all the granite stones in their original locations with new substructure and anchoring. The extents of rehabilitation include all features that comprise the commemorative bridge approach including but not limited to the bridge approach walls, engraved pylons, viewing terrace, flag plaza, stairways, balusters, and bridge façade. This project will also include the reinstallation of the flagpole and its base in the flag plaza and rehabilitation and replanting of the bridge plaza planters and the planting beds adjacent to the bridge approach to reinstate the original 1930 planting plans. The Contractor is responsible for repairing the existing irrigation in the project area, reconnecting it to the existing Park irrigation system, and restoring full irrigation coverage within the project area.

The exposed aggregate sidewalks and paving leading up to and surrounding the bridge approach will be removed and replaced to comply with an OSHA citation and to meet accessibility requirements.

The temporary stone storage area will be rehabilitated, fine graded, reseeded with turf grass, and temporarily irrigated for turf establishment.

Project Coordination

Bridge Closure and Restrictions:

For public safety, the Lincoln Memorial Bridge and abutting portions of the site shall be closed to the public during construction. The bridge roadway is a minor two-lane highway that links Indiana State Road 441 on the east side of the Wabash River and Illinois Route 33 on the west side. Both state DOT’s and the City of Vincennes have permitting authority for bridge closure. Bridge closure is prohibited at

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certain times of the year when it would adversely impact seasonal agricultural traffic. The nearest bridge is at US 50 to the north, requiring an approximately four-mile detour. The Contractor is responsible for coordination with local and state authorities and obtaining required permits for bridge closures.

Utilities:

It is assumed that on-site water and electrical utilities may be utilized by the Contractor for construction and to service the Contractor trailer. Use of local utilities instead of generators is preferred. Utilities are accessible at the Contractor’s expense but are not provided by NPS. The Contractor is responsible for coordination with local utility providers.

Construction Access and Staging:

Construction access and staging for the bridge approach restoration is anticipated to be the same as for granite removal. Granite removal was conducted using a crane located on the bridge roadway. The bridge will be closed to vehicle and pedestrian traffic for the duration of construction. Construction access to the bridge will be via Vigo Street. The park grounds and walks abutting the bridge approach will be closed to the public. The construction closure and staging area will be restricted to the perimeter boundary defined by the outside edge of the existing concrete walks. Due to the proximity to the Wabash River, an Army Corps of Engineers permit would be required to extend the construction staging area farther to the north. It is recommended to limit the construction staging area so that Army Corps of Engineers permitting will not be required. The Contractor is to provide portable restrooms for Contractor use on-site during construction. The Contractor is to provide a Contractor construction trailer with temporary utilities, as needed. Connection to local utilities is preferred over generators.

Construction Phasing and Permitting:

Construction phasing must be coordinated with permitting for bridge and highway closure while construction is underway. The Contractor is required to ensure that all areas affected by the work of this project are left in a safe and stable condition before reopening the bridge to the public. If multiple phases of construction are required to complete the project, the bridge must be left in a safe and stable condition before reopening the bridge to the public between phases. The Contractor will have full access to the approved designated project area during the construction period to expedite progress and minimize the duration of bridge closure. The Contractor is responsible for all project permitting, including but not limited to bridge closure permitting.

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Structural Report

Introduction The Lincoln Memorial Bridge Approach in Vincennes, Indiana is on the grounds of the George Rogers Clark National Historical Park (GERO). The purpose of this project is to restore the appearance of the granite elements at the bridge approach. Structural scope is expected to include repairs to the back-up wall elements, stone repairs, new anchorage design, replacing the exposed aggregate concrete sidewalks and waterproofing improvements. Below is a key plan identifying the major scope elements within the project boundary including:

• Granite clad walls/railings (highlighted in blue)

• Granite clad piers (highlighted in orange)

• Granite pavers and stairs (highlighted in red)

• Exposed aggregate concrete sidewalks (highlighted in green)

Figure 1 – Site Plan (for the purposes of the report, north will be as plan north)

Project History The Lincoln Memorial Bridge and approach was constructed in 1932. On the Indiana side of the bridge the George Rogers Clark Memorial Park was also being constructed in the 1930s. The memorial adjacent to the bridge approach was completed in 1936 with the state of Indiana taking ownership in 1939. The park became part of the NPS in 1966. The approach has experienced deterioration, soiling and displacement of the granite features due to water infiltration through stone joints and subsequent corrosion of iron pins. In addition to the iron corrosion the condition of the brick backup wall was in poor condition as well due to moisture and freeze-thaw cycling, and poor original construction. There are very early records of structural issues (as far back as the 1930s) and in 1976, 1982, and 2009, several

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projects were completed to address movement and staining. The exact scope of these projects is unknown as there are no known drawings available. In 2017 OSHA issued a citation for unsafe walking surfaces, which was related to displacement of some of the exposed aggregate concrete sidewalk panels. In June 2019 NPS worked with OSHA to restrict access and ensure employee safety following concerns over some of the granite cladding representing a falling hazard.

STRUCTURAL DESCRIPTION & ASSESSMENT

The granite cladding at the bridge approach has been removed along with much of the integral brick masonry backup, where present. The removals have exposed to view much of the underlying concrete slabs and walls, which allows for a much better understanding of the existing conditions of the underlying structure to remain. An understanding of the structure can be gathered from the six sheets in the original drawings, the documentation completed during Predesign, and site observations. The existing condition documentation occurred during the early stages of the demolition scope and included a laser scan, photo-rectified wall elevations, drone documentation, and a Matterport model (photogrammetry model available online).

Granite Clad Walls & Piers

Structural Description

The backup wall is a combination of concrete and brick masonry. Based on the original drawings the wall is typically concrete where it retains soil and serves as a foundation, with brick where it serves more as a parapet/railing. In most cases it appears the granite wall panels were attached to a backup brick masonry wall. The stones themselves vary in size but many are on the order of about 1.5-2 feet tall, 3.5- 5 feet wide and 4 inches thick (see Figure 2). Thicker header stones appear to have been used in some cases to supplement existing iron ties to tie the stone with the backup wall. It is indicated that these header courses are present at taller retaining walls and the pylons/piers.

Figure 2 – Typical Wall Parapet Section Showing Coping, Granite Cladding and Brick Masonry Backup

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The stones are typically held in place by iron pins at the top and bottom. In some cases there were also pins between adjacent stones in the same course. No relieving angles were observed during demolition so the assembly relies on stacking from a gravity perspective and the pins provide the lateral restraint. It should be noted that in many cases this wall is acting more as a composite wall rather than a veneer and backup wall system as would be constructed today. See the section in Figure 3 for a schematic of iron pin locations at one of the pylons.

Figure 3 – Iron Pins Shown at Each Course at Pylon Section

Condition Assessment

The backup brick masonry walls were typically in poor condition. The brick masonry had significant spalling and was laid haphazardly in the original construction (see Figure 4). Hollow bricks were used and not always laid in the correct orientation. Some mortar was present at the interface between the granite and the brick which was likely placed when originally installed as a ‘collar joint’. There was no air gap between the backup wall and cladding as might be expected today – rather the cladding was intended to behave more composite with the backup. Given how much water infiltrated the cladding, the use of deicing salts around the walls, and the observable displacement of stones the brick masonry is not salvageable, and in most cases has already been demolished.

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Figure 4 – Exposed Brick Masonry Backup at Failed Granite Panel

Surface staining on the stone is described in more detail elsewhere in the POR, but it should be noted that much of the staining is directly linked to the corrosion of the iron pins. Brown rust streaks on the face of the stone highlight where pins are located (see Figure 5).

Figure 5 – Staining of Stone Due to Iron Anchorage Deterioration

Prior to removal the stones themselves had displaced significantly out-of-plane as the iron pins corroded and no longer provided restraint. One stone had fallen completely out of the wall and in many other locations the stones had displaced over an inch. As water built up in the cavity between the backup wall and the stone panels it froze and displaced many of the stones outward. Over time this freeze-thaw cycling presented a life safety hazard as the stone panels displaced to the point where they could fall out of the wall assembly – leading to the current project. Shadows on the face of the walls and piers highlight the out-of-plane displacement of the cladding prior to the dismantling of the granite stones (see Figure 6).

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Figure 6 – Displacement of Stones at a Pylon

In addition to the displacement there was cracking and spalling at a handful of stones, which will need to be repaired prior to reinstallation (see Figure 7). Similarly, many of the mortar joints were in poor condition with significant mortar loss. As part of the reconstruction the stones will need to be set in a new mortar which is compatible with the stone units.

Figure 7 – Crack at Granite Cladding

Concrete testing was performed by Highbridge (chloride, compressive strength, and petrography) on several of the underlying walls and slabs in the summer of 2023, and the results are presented herein as an Appendix. While there were some exceptions the concrete is typically in better condition than expected given the age – with relatively low chloride ion content, low carbonation and high compressive strength.

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Granite Stairs & Pavers

Structural Description At the north and south ends of the bridge approach there are stairs which lead down from the bridge to the surrounding grade (see Figure 8). On the north side these stairs are incorporated into a circular terrace around the flagpole. Prior to demolition these areas were typically composed of granite stones bearing an underlying concrete structure with a setting bed.

Figure 8 – Granite Stairs at South End of Bridge Approach

Based on original drawings the stones at stairs are about 7 to 8 inches thick and the stones at paved areas appear to be closer to 4 inches thick. Drawings appear to indicate that these horizontal stones are set on a 1½ to 2-inch-thick cement mortar setting bed (see Figure 9). This was confirmed during the demolition scope, and much of the sand/mortar setting bed is still in place on the horizontal surfaces.

Figure 1 – Typical Stone Step Detail from Original Drawings

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The paver stones had significant mortar loss at joints between stair treads and several had displaced prior to removal. Many of the stones have staining and several have minor cracking and/or spalling issues that will require repair prior to reinstallation. Displacement of the stones at stairs on the north side of the approach resulted in an OSHA citation for an unsafe walking surface (see Figure 10). It appears that most, if not all, of this movement was related to individual paver displacement rather than a more global issue with the underlying slabs.

Figure 2 – Concrete Steps & Pavers on North Side

Exposed Concrete Aggregate Sidewalks

Structural Description

On each side of Vigo Street there are sidewalks that are composed of a dark pigment and exposed aggregate concrete. Two concrete mixes were used - a lighter one to set the perimeter of each slab segment and a darker one at center. This exposed aggregate sidewalk is also incorporated at some of the intermediate landings for the stairs that lead down away from the bridge approach (see Figure 11).

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Figure 3 – Exposed Aggregate Sidewalks

Based on the original drawings the concrete sidewalk is 6 inches thick and typically sites on a 6-inch gravel base (see Figure 12). In some isolated locations on the north and south of the bridge approach the concrete is poured directly over a framed structural slab.

Figure 4 - Sidewalk Section from Original Drawings

Based on provided documentation it appears that exposed aggregate concrete sidewalk elements at the bridge approach have been replaced in some areas in recent years. Despite these past projects there is still cracking, spalling, and displacement of some of the sidewalk panel segments. Several panels have heaved and represent tripping hazards in their current condition. Note that the condition is covered in more detail elsewhere in the POR.

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Framed Concrete Structure

Structural Description At both the north and south ends of the bridge approach the stairs/terraces that go down to the surrounding grade are concrete framed structures. Most of these spaces are inaccessible crawlspaces but there is an underground storage tunnel on the north side below the flagpole that can be accessed (see Figure 13).

Figure 5 – N-S Section at North Stairs Showing Storage Tunnel and Crawlspace Below Stairs

Running in the east-west direction below the flagpole steps/terrace the underground storage tunnel that is concrete framed with limited areas of brick masonry infill (see Figure 14). Based on original drawings the concrete slab framing these areas is typically 9 inches thick and supported on a series of beams, columns, and walls with shallow spread footings. There is a slab on grade at the floor of this storage room, but not in the crawlspaces.

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Figure 6 – Photo Inside the Storage Tunnel

The storage room has experienced significant water infiltration through the concrete slab above. At joints in the concrete construction stalactites have formed. Original drawings that have been provided do not indicate any waterproofing on the top side, and even if present it appears to have largely failed.

Several brick masonry infills are present in this below grade space, and where observed are in poor condition with spalling. Some limited cracking and spalling of the concrete was noted, but the concrete overall appears to be in fair condition (see Figure 15).

Figure 7 – Concrete Conditions at Below Grade Concrete Structure

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STRUCTURAL DESIGN GUIDELINES

Applicable Codes & Standards The project will be governed by the following codes:

• 2021 International Building Code (IBC)

• 2021 International Existing Building Code (IEBC)

The following standards will be followed as specified by the governing codes:

• ASCE 7-16 Minimum Design Loads (and Associated Criteria) for Buildings and Other Structures

• ACI 318-19 Building Code Requirements for Structural Concrete

• TMS 402-2016 Building Code Requirements for Masonry Structures

• AISC 360-16 Specification for Structural Steel Buildings

Structural Loads The loads presented below assume the structure is Risk Category II (ASCE 7-16, Table 1.5-1).

Live Loads

The following values are specified by the applicable codes and standards:

Occupancy or Use Live Load

Uniform (psf) Concentrated (lbs)

Sidewalks & Drives Subject to Trucking 250 8,000 Pedestrian Sidewalks & Terraces 100 - Roof 20 - Vehicle Barrier - 8,000a @ 2’-3” Guardrail 50a plf 250a a Loads for vehicular barriers and guardrails are applied horizontally. Note that these elements should also consider AASHTO loading requirements as well.

Snow Loads The following loads and parameters are specified by the applicable codes and standards:

Ground Snow Load (ASCE 7-16, Figure 7.2-1) pg = 20 psf

Surface Roughness Category (ASCE 7-16, §26.7) C

Exposure Factor (ASCE 7-16, Table 7.3-1) Ce = 0.9

Thermal Factor (ASCE 7-16, Table 7.3-2) Ct = 1.2

Importance Factor (ASCE 7-16, Table 1.5-2) Is = 1.0

Flat Roof Snow Load (ASCE 7-16, Eqn. 7.3-1) pf = 15 psf

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Wind Loads

Basic Wind Speed (by jurisdiction) V = 105 mph

Wind Directionality Factor (ASCE 7-16, Table 26.6-1) Kd = 0.85

Exposure Category (ASCE 7-16, §26.7) C

Topographic Factor (ASCE 7-16, §26.8) Kzt = 1.0

Ground Elevation Factor (ASCE 7-16, Table 26.9-1) Ke = 1.0

Gust Effect Factor (ASCE 7-16, §26.11) G = 0.85

Enclosure Classification (ASCE 7-16, §26.12) Enclosed

Internal Pressure Coefficient (ASCE 7-16, Table 26.13-1) GCpi = 0.18

Net Wind Design Pressure Pnet30 = 20.6 psf

Adjustment Factor (Figure 30.4-1) λ = 1.21

Design Wind Pressure (C&C) p = 25.0 psf

Seismic Loads

The seismic parameters dependent on soil shall be confirmed by a geotechnical engineer.

Soil Site Class (Assumed) D

Short Period Mapped Spectral Accel. (USGS) Ss = 0.497 g

One Second Period Mapped Spectral Accel. (USGS) S1 = 0.161 g

Short Period Design Spectral Acceleration SDS = 0.464 g

One Second Period Design Spectral Acceleration SD1 = 0.244 g

Seismic Design Category (ASCE 7-16), §11.6) D

Seismic Importance Factor (ASCE 7-16, Table 1.5-2) Ie =1.0

Architectural Component Coefficient (ASCE 7-16, Table 13.5-1) ap = 1

Architectural Component Coefficient (ASCE 7-16, Table 13.5-1) Rp = 2.5

Horizontal Seismic Force (ASCE 7-16, Eqn. 13.3-1) Fp = 0.22*W

Note that wind will control the horizontal anchorage of the stone veneer elements over seismic for elements less than about 8-10” thick, but that seismic may control the overall wall/pylon behavior and coping stone anchorage in some situations.

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STRUCTURAL MATERIAL SPECIFICATIONS

For new structural elements, it is assumed the provided materials will meet the following specifications:

Concrete

• Compressive Strength f’c = 4000 psi typical (original)

• Concrete Density ϒ = 150 pcf normalweight

• Reinforcing Bars ASTM A615 Grade 60

• Welded Wire Fabric ASTM A1064 (65 ksi min. yield)

Any concrete patching should match the existing in terms of physical properties as much as possible.

Steel

• Stone Anchorage Pins/Angles Type 316 Stainless Steel

Masonry

• Repointing/parge coat to be determined based on testing

• Any replacement brick masonry should be compatible with the existing to remain

• CMU may be proposed an alternate for the backup wall in some or all locations

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STRUCTURAL REPAIR OPTIONS

Non-Stone Elements

Flagpole & Light Poles

As part of the repair work there are a total 4 light poles and one flagpole that will need to be removed to facilitate the proposed work. The current approach is to reinstall the flagpole and light poles using existing attachment details once work is complete.

Concrete Repairs

On the north side of Vigo Street there is an underground framed concrete structure that serves as a storage area and crawlspace. The total estimated footprint of this area is about 5,000 square feet although only a small portion is easily accessible from below. Similarly, on the south side of the project the existing stairs sit on an underlying concrete structure above a crawlspace which represents an additional 3,000 square feet. The condition of the top side concrete and waterproofing is unknown as the areas are still covered with a mortar/sand setting bed and in some areas concrete sidewalk panels.

Based on site observations it should be assumed that the entire area (8,000 square feet) will require new waterproofing, and some of the area will require top side concrete repairs. The contractor will need to gain access to the crawlspaces and rooms below the framed slabs as well to assess the condition and perform concrete repairs, as required.

For the concrete repairs the condition has not yet been exposed on horizontal surfaces which makes it challenging to establish repair quantities. An allowance will need to be made as part of the project with unit costs from the contractor to adjust up or down for the actual quantity of repairs required. For the POR it is recommended that it be assumed 10% of the top side and bottom side of concrete structure will require repair – so about 2,000 square feet of concrete patching repairs total.

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As the stones were removed from vertical surfaces, it became clear that there is about 8,000 square feet of vertical concrete surfaces that will be exposed. While some of this surface is still not visible, it should be assumed that about 20% of this area (1,600 square feet) will require repairs to address spalling, cracking, and/or remove embedded ferrous elements.

The original drawings indicate the original concrete has a compressive strength of 2 ksi; however, testing indicates that the actual strength is much higher. There will need to be attention to specifying an appropriate patching mortar compatible with the existing concrete. For small patch areas it is recommended that a trowel applied mortar be utilized. It is anticipated that a patching mortar will be utilized for most repairs. If there are isolated, large areas requiring repair it will be better to form up and pour the concrete. Any exposed reinforcing steel at patch areas should be cleaned and have a corrosion inhibitor applied.

Some crack repairs are also likely to be required, but again quantities are unknown. For pricing purposes during the POR preparation, the cost of this scope can be assumed to be included in the quantities for patching repairs. Structural cracks should be repaired using an injection epoxy.

A comprehensive survey of the underlying concrete has not yet been performed. Following complete removal of stone, bricks, sidewalks, and setting bed this survey will need to be the first step in establishing repair quantities and locations. In addition to visual observation the concrete will also need to be sounded in order to remove loose or damaged sections.

Sidewalks New concrete sidewalk repair recommendations are covered in more detail in the civil section of the POR. Based on site measurements it is anticipated that about 10,000 square feet of new sidewalk work will be required. The existing curbs are to remain in place.

It is anticipated that some of the underlying gravel below sidewalks will require replacement and/or compaction before placing new sidewalks. In some locations such as the north and south stairs/terraces the sidewalks are sitting on a concrete structure. Those repair quantities are included in the ‘concrete repair’ section of the report.

The concrete mix for the sidewalks at the site is unique with a dark one with exposed aggregate used as the primary mix and a lighter mix with smaller aggregate used for the borders of sidewalk panels. Similar mixes are used elsewhere within the park so it will be important to match the existing and replace in kind. The park has specifications for past mixes used at the site which should be referenced.

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Stone Elements

Brick Masonry Repairs Based on provided documentation it is estimated that there was about 15,000 square feet of granite cladding that was removed from walls and pylons. Much of the brick was also demolished during the stone removal. Whatever remains on site should be demolished as the brick is in poor condition and not salvageable. A new masonry substrate will be needed as part of the granite reinstallation. This can be done with brick, CMU, additional concrete, or some combination of all three materials. The backup wall will need to geometrically match the original masonry and will need to be engineered to resist all applicable gravity and lateral forces (vehicular, seismic, and wind). The original drawings, laser scan, existing stones and existing condition of the concrete that remains should all be referenced when establishing the required geometry for the rebuilt substrate wall.

Stone Stairs & Pavers

Granite stair elements and sidewalk pavers have been removed and will now need to be cleaned, repaired and reset to address tripping hazards and a recent OSHA citation for an unsafe walking surface.

Cleaning is discussed elsewhere in the POR, but an allowance will need to made for structural repairs for these granite elements off site – which could include injection crack repair, localized dutchman/patches, and limited stone replacement. For pricing purposes, it is recommended that it be assumed 5% of the stones will require structural repair and 5% will require replacement. Total plan area for stone pavers and stairs is about 3,500 square feet. For all stones assume a new 2-inch setting bad above the concrete sub-structure is to be removed. Once removed a survey of the existing conditions will need to be performed, followed by concrete repairs, and the introduction of a new setting bed.

Past reports have recommended waterproofing on the portions of the back-up wall. Given that the walls behave compositely this is not recommended as it could trap moisture inside and accelerate deterioration.

Stone Wall Cladding

The granite cladding on the walls, along with coping stones, have been removed and catalogued under a separate contract. While off-site, the stones will be cleaned as part of this project. Cleaning is discussed elsewhere in the POR, but an allowance will need to made for structural repairs for these granite elements – which could include injection crack repair, localized dutchman/patches, and limited stone replacement. For pricing purposes it is recommended that it be assumed 5% of the stones will require structural repair and 5% will require replacement. Total surface area for stone pavers and stairs is about 15,000 square feet. For all stones assume a new one-inch collar joint along with new mortar between stones.

Past reports have indicated that the wall should have sealants between joints, a wall cavity, and weep holes. This appears to be inconsistent with how the wall was originally constructed. Trying to make the wall behave more as a modern veneer system is not recommended as it could compromise the structural integrity of the existing wall assembly and cause additional issues in the future.

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Stone Anchorage

The existing iron pins will need to be replaced in their entirety. The current assumed approach is that new pins will be made with stainless steel and match the original geometry and layout. These pins will be installed into the new backup walls using an adhesive anchorage system. Based on information that is currently available it should be assumed that there will be about one anchor for every 3 square feet of wall surface area (minimum two anchors per stone) or about 5,000 total stainless steel anchors – each about 6 inches long and a couple inches wide.

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Conservation Report

Overview of Existing Conditions The current scope of the project is to remove the granite panels from the Lincoln Memorial Bridge, clean and treat any deterioration, and reinstall the panels in their original location after any structural conditions are remediated. Jablonski Building Conservation, Inc. (JBC) was asked to provide cleaning methodologies to remove the heavy soiling conditions and to comment on the existing conditions of the historic materials.

The granite panels themselves are in good condition. However, there was a great degree of displacement along the bridge approach and the towers prior to stone removal, along with heavy iron stains and other types of soiling. (Displacement and the condition of the substrate is discussed in the Structural section.)

Figure 8: Lincoln Memorial Bridge looking south. Note displacement of panels on the bridge towers.

Soiling Patterns:

Four main types of soiling exist: (1) iron staining, (2) efflorescence or calcium carbonate crusts, (3) biological growth, and (4) black staining. The majority of the soiling patterns are all driven through water infiltration. Where mortar joints had failed, the interior bedding surfaces were damp indicating that the wall system was retaining water.

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Iron staining, present mainly on the walls of the bridge approach, is visually disfiguring. The iron staining is caused by the corrosion of the ferrous anchors. Iron stains appeared soon after construction. Early photographs of the bridge show staining or discoloration on the granite panels on the bridge approach.

The prolonged deposition of iron oxide on the stone has resulted in a thick ferrous crust in some locations. The amount of iron staining also indicates that the anchors are in poor condition.

Figure 9: Lincoln Memorial Bridge, Indianapolis News, 28 April 1934

Previous attempts have been made to clean the iron staining from the granite panels. According to Park staff, this included using a muriatic acid poultice that etched the stone and caused efflorescence. It is likely that the muriatic acid was not fully rinsed free from the granite.

Figure 10: Heavy iron staining on a granite panel.

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Efflorescence and calcium carbonate crusts are present. This condition is also driven by water infiltration in the wall system, as water traveling though the masonry and mortar deposits salts and carbonates onto the granite. Efflorescence is water soluble. The carbonate crusts are caused by calcium hydroxide in the mortar being carried by the water and deposited on the stone surface where it carbonates to form an insoluble crust.

Figure 11: Arrow indicates efflorescence adjacent to an iron stain.

Biological growth is present at the base of the walls and along any open joints. This is related to water sitting on the surface of the stone.

Figure 12: Biological growth along a mortar joint.

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Thick black deposits are present only on the towers of the bridge. They appear to originate from the joints. It is possibly a by-product of an earlier attempt at waterproofing the structure, or a type of biological growth.

Figure 13: Black soiling on bridge towers.

Granite Deterioration Conditions:

The granite panels have two main deterioration conditions: (1) surficial scaling, and (2) cracks.

Scaling, or small shallow spalls on the surface of the stone, is present on the panels adjacent to planters and along open joints where water can collect. The scaling is likely the result of freeze-thaw deterioration. The planters filled with soil can retain water which then gets absorbed into the granite panels. The cyclical freezing and thawing of the water in the granite during the winter can cause the granite to scale.

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Figure 14: Surficial scaling on a granite panel.

Three cracks were noted during the bridge survey. They were found on the staircases on each side of the bridge approach.

Figure 15: Crack at corner of granite panel.

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Repair Recommendations The Design-Build Contractor shall be responsible for developing alternatives and mockups, providing assurances of performances, and working through the review process by the State Historic Preservation Office documenting compliance with the Secretary of the Interior’s Standards and Guidelines.

Cleaning JBC tested various cleaning products and procedures to determine the gentlest, yet most effective means for removing the various soiling conditions from the granite panels. Several products were tested to remove biological growth, iron stains, efflorescence and carbonate crusts, and the black stains/deposits. The full cleaning tes report is located in the appendix.

Based on the results of the cleaning test, Cathedral Stone Products Heavy Duty Cleaner was the most successful product in removing the general soiling, iron stains, black stains, and biological growth from the granite. Sure Klean Marble Poultice Powder mixed with Sure Klean Iron Stain Remover is recommended for spot treatment of heavy ferrous stains. Mechanical thinning/removal of carbonate crusts followed by an undiluted application of ShoreBest 2377 HD Concrete, Mineral & Efflorescence Remover cleaned the majority of the carbonate deposits from the stone.

Prior to full-scale implementation of the cleaning procedures, the contractor must perform mock-ups.

The mock-ups will provide a better understanding of the effect of the cleaning as well as fine tune any application methods and exposure times.

Cleaning Procedures

JBC recommends that general cleaning be performed first followed by spot removal of residual stains.

General Cleaning Product: CSP Heavy Duty Cleaner, manufactured by Cathedral Stone Products, Inc

Procedure:

1. Prewet the surface to be cleaned.

2. Apply a thick, even layer of the cleaner using acid-resistant brushes or rollers. Gently scrub the surface to improve results.

3. Allow the cleaner to dwell for the time established during testing and mockups. For the CSP

Heavy Duty Cleaner, the dwell time should be 5 minutes. Do not let the cleaner dry on the surface. If drying occurs, lightly wet the surface with fresh water and reapply the cleaner.

4. Scrub the treated surfaces to loosen soiling.

5. Rinse thoroughly with clean water. Pressure shall not exceed 1000psi. Rinse until the pH of the cleaned surface reads neutral (pH of 7) or equal to that of the rinse water.

Iron Stain Removal Product: Poultice of Sure Klean Iron Stain Remover mixed with Sure Klean Marble Poultice Powder, by ProSoCo, Inc.

Procedure:

1. Mix the chemical cleaner with the poultice powder until a paste is formed.

2. Apply the paste to a dry surface with a natural bristle brush or a plastic scraper.

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3. Cover the poultice with plastic and allow it to dwell overnight.

4. Remove the plastic and allow the poultice to completely dry.

5. Scrape the dried poultice off the surface with a plastic or wooden scraper.

6. Scrub the area with a nylon bristle brush.

7. Rinse thoroughly with clean water. Pressure shall not exceed 1000psi. Rinse until the pH of the cleaned surface reads neutral (pH of 7) or equal to that of the rinse water.

8. Repeat the process once, if iron stains remain. Notify architect or owner if additional stain remains after two applications.

Carbonate Crust Removal

Product: Mechanical removal using a hammer and chisel followed by SB 2377 HD Concrete, Mineral & Efflorescence Remover, manufacture by Shore Corporation

Procedure

1. Carefully remove or thin heavy encrustations of carbonate deposits using a hammer and a sharp chisel. Be sure not to mar or scratch the granite surface. The intent is to cleave the deposit from the granite. Thinner deposits can be left as.

2. Apply the undiluted cleaner to the deposit. Allow the cleaner to dwell for at least 10 minutes.

Periodically scrub and apply additional cleaner during the dwell period to facilitate removal. No metal brushes or scrapers are to be used. If necessary, the cleaner can dwell longer, based upon the results of mockups.

3. Rinse thoroughly with clean water. Pressure shall not exceed 1000psi. Rinse until the pH of the cleaned surface reads neutral (pH of 7) or equal to that of the rinse water.

4. Repeat the process once, if crust remains. Notify architect or owner if additional crust remains after two applications.

5. Aim to remove 85% of carbonate deposits.

Repairs

The following repair methods are intended to address the limited scaling and cracks observed on the granite panels prior to removal. Additional treatments may be necessary after the granite panels are removed from the bridge substructure. The level of deterioration on the reverse face of the panels and any damage that may have occurred during removal is not known.

1. Tool surface scaling from the granite.

a. Sound masonry units in-place using the “ring test method” in order to distinguish fully intact stone from those in which delamination may be hidden or pieces of unstable material may not be immediately visible.

b. Using a hammer and chisel or pneumatic air chisel, scale off all loose pieces of stone, including surface material in powder or granular form, and detachments of planer elements, spalls, and chips. Tool the affected area to match adjacent work and so that water can effectively shed from the masonry surface.

c. Once all loose material is removed, the surface of the granite panel can be flame finished to feather the edges of scaled areas and to match the original surface texture of the panels.

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2. Patch cracks that do not travel through the thickness of the panel.

a. Cracks larger than hairline, but narrower than 3/16 inches shall be filled with injectable grout, introduced through ports which should measure 1/4 inch in diameter and be spaced as required. Entry ports and crack surface should be subsequently patched with composite patching mortar to match the color, level, texture, and profile of surrounding clean masonry.

b. Cracks equal to or wider than 1/4 inch shall be routed and filled with composite patching material to match the color, level, texture, and profile of the surrounding clean masonry.

3. Repair units with cracks running completely through unit by re-joining and pinning pieces using adhesive and stainless steel pins.

4. Point joints between units using a filler material that is physically and aesthetically compatible with the surrounding granite. New joint materials must have a greater water permeability and be softer than the granite.

5. Install lead weathercaps in all sky-facing joints.

6. Install weepholes at regular intervals along the paneled walls. The weepholes will allow water to leave the wall system and not become trapped behind the granite panels.

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Civil Report

Applicable Codes and Standards:

The NPS, including the Denver Service Center (DSC), is the governing agency (AHJ) for the project. The project will adhere to the following applicable codes and standards, in accordance with the NPS DSC design standards:

• ABA (Architectural Barriers Act) Accessibility Standards

• APWA (American Public Works Association)

• ASCE (American Society of Civil Engineers)

• ASLA (American Society of Landscape Architects)

• INDOT (Indiana Department of Transportation)

• FHWA FLH PDDM 2018 (Federal Highway Administration - Federal Lands Highway - Project

Development and Design Manual)

• ACI (American Concrete Institute)

• ACPA (American Concrete Pipe Association)

• ANSI (American National Standards Institute)

• IBC 2021 (International Building Code)

• OSHA (Occupational Safety and Health Administration)

• PCI (Precast/Pre-Stressed Concrete Institute)

• PDI (Plumbing and Drainage Institute)

Overview of Existing Conditions (Findings) Plan north consists of a flagpole mounted on a platform consisting of stone pavers, with stone steps on either side leading to the aggregate concrete sidewalk below. The flagpole area has 3 area drains, north east and west of the flagpole. The east and west drains appear to be clogged by leaves and debris, and do not appear to be functioning. The northern drain is free from debris on the surface, but could potentially be clogged somewhere in the pipe. Numerous stone pavers in the flagpole area are missing the sealing material used between individual pavers. The aggregate sidewalk in this area is in mostly good condition, with some cracks/patches, along with some high/low points that have developed over time. There are 2 planters in the flagpole area with unclear drainage outfalls. The walls in this area show signs of water infiltration and are pushing out in some areas.

Plan east consists of the area beneath the bridge, with NPS property stopping where the stone façade stops. The stone façade of the bridge in this area has dark spots (organic material according to NPS). This staining is addressed in the Conservation section of this report.

Plan south consists of a stone paver staircase area, along with aggregate pavers above and below the stairs. The aggregate pavers in this area are in worse overall condition than plan north, with more cracking and patches. On the upper level, the curb is in very poor condition, with many patches and a low point above the storm inlet. The stone staircase is in ok condition, with many of the pavers missing the filler material between individual pavers, as well as some larger gaps potentially from stone cracking. The walls in this area also show signs of water infiltration.

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