Overview

Our products include the original T-WALL® Retaining Wall System as well as our new Inverted T-WALL®. Both of these systems are precast, modular gravity-type retaining walls composed of structurally reinforced, monolithic T-WALL units.

The standard T-WALL Retaining Wall System decreases in stem length course by course – reducing materials, excavation, and backfill as compared to other wall systems.

By placing the shortest stem lengths on the bottom course, Inverted T-WALL minimizes the need for excavation and shoring while creating new real estate at the top of the wall.

Included in the T-WALL Package: engineering, stamped/sealed drawings, material supply, and construction assistance and coordination. Learn more about the T-WALL package here.

T-WALL Units

Unit Details

Monolithic T-WALL units are made of heavy-duty, structurally reinforced concrete – a proven industry standard for long-term use.

T-WALL units come in three basic face sizes. Typical units have a rectangular face and a stem that extends into the retained earth. The length of the stem is designed to resist the earth pressure on the unit.

Special units, such as slope-top and pipe-penetration units are designed specific to each project.

Units are self-finishing, but can be cast with an integrated coping.

 

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Unit Heights & Weights

Structural Options

VERTICAL T-WALL

T-WALL is typically constructed vertically with no batter. Our tallest vertical wall to date is a 50 ft high bridge abutment for the Kosciuszko Bridge replacement project in New York.

 

In general, T-WALL has shorter base width requirements than other systems. T-WALL stems also decrease with each successive course as opposed to systems that maintain a constant reinforcement length.

With a shorter base width and diminishing stem lengths, T-WALL requires less excavation, less temporary support, less granular backfill, and fits better within the construction limits.

Learn more about the advantages
of T-WALL here.

T-WALL is designed in accordance with the applicable sections of AASHTO and State DOT codes. Allowable stress design (ASD) or load resistance factor designs (LRFD) can be provided.


BATTERED T-WALL

T-WALL can be erected on a batter. A battered wall design reduces the base width – a benefit when working within tight construction limits or limited right-of-ways.

A typical batter is 1:6, but batters ranging from 1:12 to 1:4 can be attained.

NEW INVERTED T-WALL

Inverted T-WALL is our latest structure. T-WALL units with the shortest possible stems are placed at the bottom of the wall and successively longer units are stacked on top.

The incrementally longer stems of Inverted T-WALL act as an angled back face, much like the angled back face of a battered wall. Because of the angled back face, the active wedge area behind the Inverted T-WALL stems is reduced and consequently the active lateral pressure coefficient is lowered.

Shortening the stem lengths at the bottom of the wall does not change the bearing pressure significantly as the eccentricity would be minimal using the Inverted configuration.

Inverted T-WALL combines all the benefits of standard T-WALL with minimal or no need for shoring and excavation. Optimal for rail and highway expansion in areas with extremely limited right-of-way, Inverted T-WALL keeps existing lanes or tracks open while adding new.

Learn more about the advantages
of Inverted T-WALL here.

T-WALL & RAILROAD LOADS

Whether standard T-WALL or Inverted, our larger units with a  5′ x 7’6″ face are used for railroad loads. The ‘Top’ unit face extends above the stem, allowing room for ballast, sub-ballast, and utilities.

 

Class I railroads prefer the heavy-duty structural qualities of T-WALL and Inverted T-WALL. No exposed metal eliminates corrosion concerns from tank car leaks, ultra-low sulfur diesel fuel, soil chemistry, and stray current.

 

T-WALL is designed in accordance with the applicable sections of AREMA such as Section 2.2.3c for surcharges. Allowable stress design (ASD) or load resistance factor designs (LRFD) can be provided.

The load diagram shows lateral earth pressures based upon the typical section shown above. The standard heavy rail (Cooper E-80) surcharge load used for our design is 1882 pounds per square foot per AREMA Section 2.2.3c.

The T-WALL System is designed for the sum of the lateral earth pressure plus the surcharge loads from the adjacent tracks. The lateral earth pressure from the train surcharge is calculated as a strip load based upon a Boussinesq distribution, per AREMA Section 20.3.2.2.


Back-to-Back

T-WALL can be constructed back-to-back to provide a great alternative for flyovers and other elevated structures. The width of back-to-back sections can be minimized with double-ended units and/or interlaced stems. Construction can occur within the footprint of the structure further reducing right of way needs and maintaining strict construction limits.

Project Information:
Required from the Owner or Engineer

Site Analysis
It is the responsiblity of the owner/engineer to provide a geotechnical report that provides a site analysis. The analysis should include:

  • Bearing Capacity
  • Global Stability
  • Settlement/Consolidation
  • Scour
  • Ground Water/Surface Drainage

Required Information
The following information is required in order to provide an accurate, efficient design for each project:

  • Project specifications
  • Geotechnical report
  • Existing topography
  • Plan and profile of proposed walls
  • Surcharge loads on the wall (such as traffic or buildings)

Backfill



Integral to the Structure

The granular backfill between the T-WALL stems is integral to the system. The structure will NOT perform with incorrect backfill. Backfill is placed and compacted (or poured) between the unit stems, providing the mass needed to resist the lateral loads of the retained soil, the friction to ensure that the granular fill and T-WALL units act as one body, and the internal drainage needed to prevent the build-up of hydrostatic pressures on the structure under properly designed, normal site drainage conditions. All of these factors are critical and directly impact the performance of the T-WALL structure.

T-WALL Requires Less Backfill

The diagram below illustrates T-WALL and MSE backfill requirements for 240 pcf highway loads. T-WALL also requires significantly less backfill for rail loads.

 

Wide Range of Backfill Materials

A wide range of backfill material can be used, depending upon the loads on the structure, water conditions, and backfill availability. The all-concrete precast units eliminate most soil chemistry concerns and allows the use of nonstandard, economical backfill materials:

  • Quarry Waste
  • Crushed Recycled Concrete
  • Old Ballast
  • Washed Out Concrete Mixes
  • Bottom Ash from Power Plants

Lightweight Backfill

Lightweight backfill can be used with the T-WALL Retaining Wall System to reduce bearing pressure which can eliminate or reduce the need for foundation improvements and subvert additional loads on existing structures. Examples of lightweight fill include:

  • EPS (i.e. Geofoam)
  • Cellular Concrete
  • Expanded Shale
  • Blast Furnace Slag
  • Pumice, Vermiculite, & Perlite

Architectural Finishes & Structural Details

Architectural Finishes

T-WALL can be produced in a wide variety of finishes. Stainings, coatings, and architectural elements can also be applied following construction. The Neel Company can also create custom logo pieces.
Coated Form Finish
Ontario Ashlar
Custom Logo
Stacked Stone
Custom Finish
Dry Stacked Stone
Fractured Fin
Small Aged Ashlar
Large Ashlar Stone
Exposed Aggregate
Custom Finish
Custom Finish

Structural Details

T-WALL can accommodate and integrate easily with utilities, soundwalls, guardrails, light and catenary poles, pipes, and more. Crashwalls can be attached when necessary while custom faces can double as seawalls.

Construction

Fast, Easy Installation

Contractors continually provide us with positive construction feedback. Once contractors use our system they prefer its ease and speed of installation as compared to other systems.

For a brief overview of T-WALL construction please see the video at the top of the page.

Construction Manuals

2.5′ x 5′ Units

5′ x 7.5′ Units

Railroad

Our construction manuals have been prepared as a guide to building T-WALL Retaining Wall structures. There contents should be thoroughly reviewed by the contractor and the superintendent responsible for construction prior to the delivery of the T-WALL units to the job site. The Neel Company and/or its Licensed Producers will provide job site technical assistance to help the contractor implement correct construction procedures.