Project Overview

This truck dealership in Clarksburg, MD, required a major expansion to develop usable land for its growing vehicle inventory. Located adjacent to Interstate 270, the property’s steep slope was converted to park commercial trucks, pickup trucks and cargo vans. Two CornerStone 100 retaining walls were designed and installed to convert this challenging terrain into a terraced parking lot extension.

The lower wall was built close to the property boundary to optimize the dealership’s visibility from I-270’s northbound lanes. The retaining wall’s raised height offers high-value exposure to passing traffic while showcasing their extensive inventory of commercial vehicles.

The upper wall, reaching up to 26 ft. (7.9 m.) high, features an eye-catching blue clock mounted on its facing. This distinctive landmark draws attention to the dealership and has become a recognizable feature of the local landscape. Together, the two CornerStone 100 walls stabilize the property’s hillside with a reinforced parking solution that supports its continued growth.

Challenges & Solutions

Several design and construction challenges were addressed through Roche Brothers’ expertise and Earth Retention’s strategic wall designs. With trusted blocks produced by local CornerStone 100 producer, York Building Products, the project is a notable Interstate 270 landmark.

Key challenges presented by this project’s land development included:

• Expanding usable commercial land along property’s steep slope
• Building walls close to Interstate 270 to maximize traffic visibility
• Stabilizing large slope for heavy, active loading considerations
• Cost-effectively reinforcing parking lot above upper wall during construction
• Abutting lower wall along large concrete cast-in-place stormwater structure

A primary constraint was the property’s steep terrain, which required a calculated approach to these planned retaining walls. The terraced design soundly stabilized the slope and delivered long-term strength and durability to withstand substantial loading capacities.

The terraced wall combination created valuable parking space above the lower wall, which seamlessly integrated an existing cast-in-place stormwater structure. The upper wall accommodated necessary base elevation changes along the slope’s natural terrain, and contributes to safe, efficient stormwater conveyance.

Wall Design

These geogrid-reinforced CornerStone 100 wall designs deliver wide-ranging advantages, from land maximization to design and on-site versatility. Furthermore, they are tailored to meet the active loading requirements of large trucks, service vehicles, and ongoing roadway traffic. StrataGrid geogrid reinforcement was used to stabilize the slope’s retained soil and distribute heavy loads from the paved surfaces above.

The design also integrated stormwater management solutions to protect the walls’ integrity and minimize future maintenance. Each of the CornerStone 100 blocks are filled with drainage gravel, bolstering the walls’ structural mass and drainage capabilities. Perforated drainage piping was installed near the base, daylighting through the face of the wall to efficiently convey runoff.

A graded portion below the toe of the upper wall includes a subtle swale filled with large rocks. This effectively controls water flow velocity and safely guides water away from the wall. These solutions, combined with storm drains behind the walls, reduce hydrostatic pressure buildup behind the walls to increase long-term resilience.

MHG and Earth Retention expertly planned and designed the retaining walls and infrastructure to bolster functional space and structural performance.

Installation

The retaining walls’ successful construction was completed by local contractor Roche Brothers, who have extensive experience installing CornerStone 100. Their familiarity with the product and skilled installation helped the project remain on-schedule and minimize construction delays. The walls were installed sequentially – first the lower wall, which abuts both sides of a pre-poured cast-in-place concrete stormwater management structure, then the upper wall.

Compact construction equipment was used to transport pallets of CornerStone 100 blocks to staging areas on site. The CornerStone 100 block’s hollow core design allows for easier handling to access complex and space-constrained sites. The SecureLug connection system ensured precise block alignment and consistent setback, further expediting installation while maintaining high-quality results.

During construction of the upper wall, an existing asphalt parking lot extended close to the excavation limits required for geogrid reinforcement. The excavation zone extended at a 1:1 layback ratio, which would have encroached on the pavement. Initially, temporary shoring was proposed to support the existing asphalt surface during construction, but Roche Brothers offered a more cost-effective alternative.

Their team recommended cutting and removing a section of the asphalt, allowing for open excavation and geogrid placement, then repaving the area afterward. This practical, value-engineered solution eliminated the need for costly shoring, saving significant expenses without compromising wall strength or construction timelines.

Block Aesthetics

Beyond performance, the dealership’s new retaining walls were designed to complement the surrounding environment and elevate the dealership’s roadside presence. The project’s Coastal Tan color blocks by York Building Products complement the greenery and forested backdrop. The color and split-face block texture soften the appearance of the large walls and blend with the site’s natural elements.

Cap units along the top course of both walls protect the structures and create a clean, polished finish. Working with the terrain’s natural slopes, finishing details for both walls include gradual step-up designs.

The property’s most striking feature is the upper wall’s massive 12 ft. (3.66 m.) blue clock. It’s mounted directly onto the face of the upper wall using discreet brackets secured between block courses. This lightweight decorative addition not only draws attention from passing vehicles but reinforces the dealership’s visibility and regional recognition.

Project Summary

This project demonstrates how CornerStone 100’s retaining wall system enables developers to turn steep, unusable land into purpose-driven commercial space.

Key achievements of these CornerStone 100 retaining walls include:

• The retaining walls covered over 11,500 sq. ft. (1,070 sq. m.) of facing area
• Maximized commercial land use, enhanced truck center’s market recognition
• Terraced property design delivers slope stability, easily handles heavy loading
• Integrates exceptional drainage and critical stormwater management system

The CornerStone 100 retaining wall system’s simplicity and versatility make projects easier, from planning and construction to unique finishing details. Whether projects require complex soil reinforcement or massive standout clock features, CornerStone’s engineered wall system delivers trusted, proven solutions.

About CornerStone 100 Retaining Walls

Learn more about the CornerStone 100 retaining wall system by checking out its block specifications and CAD details, or try CornerStone’s free, comprehensive wall design software.

For further insight, contact your nearest CornerStone 100 retaining wall block supplier.

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This project was successfully completed thanks to York Building Products (MagnumStone block producer), Roche Brothers (Installer), W.F. Delauter & Son (Site Contractor), Earth Retention (Wall Designer) and MHG (Civil Engineer).