Heavy Duty Grating Catalog

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Welded Heavy-Duty products are designed to meet the need for gratings subject to heavy rolling and static loads such as highways, plant floors, loading docks, inlet covers and airports. Since these conditions can range from light-duty forklifts to semi-trucks and trailers carrying maximum allowable highway loads, heavy duty gratings are manufactured in a wide variety of bar sizes and spacings. Indiana Gratings Heavy-Duty products are designed in accordance with current AASHTO specifications for H-10 through H-20 loads. Automobile and forklift loads are similarly evaluated with loads calculated and distributed in accordance with the criteria shown below. If your particular load conditions are not adequately addressed in the load criteria presented, please contact our engineering staff and we will be pleased to assist in the selection of a heavy-duty grating to satisfy your specific needs. 

Heavy Welded Gratings


Because heavy-duty gratings are commonly subjected to shock and impact loads it is highly recommended that all open ends be banded. The welded band bar helps distribute impact loads and minimizes panel distortion when subjected to repetitious traffic patterns.

Serrated Surface

Optional serrated bearing bars can be specified to enhance skid resistance. 

Bearing Bar Selection

Once the bar spacing is selected, the bearing bar size must be specified based upon the anticipated load and the clear (unsupported) span to be served. The load tables on pages 11-13 provide the maximum safe clear simple span for our most popular products based on the maximum traffic conditions defined. These tables incorporate strict limitations where design deflection shall not exceed the lesser of L/400 of the safe span indicated or 1/8 of one inch (.125).

Cross Bar Selection

While bearing bar selection is critical for specifying a proper heavy-duty grating for your application, the life-cycle of your installation will often be influenced by selection of the appropriate cross bar. The table below details alternative cross bar sizes available. The sizes listed for Standard Loads are the standard twisted square or round cross bars supplied by Indiana Gratings for a particular bearing bar size. These sizes have been selected to maximize manufacturing efficiency and economy. It is suggested that these sizes be specified when the grating is subject to intermittent traffic and only occasional full capacity loading.

The cross bars listed for Severe Loading are optional and will provide superior rigidity and durability when gratings are subjected to intense, continuous or repetitious traffic. Ideal for trench covers, highways and inlet grates, these cross bars enhance lateral stiffness thereby extending the service life of the grating. When specifying gratings with bearing bars centered at 1-3/8”, 1-7/8” or 2-3/8”, consideration of Severe Loading cross bars is highly recommended. NOTE: IN THE EVENT THAT A CROSS BAR SIZE IS NOT SPECIFIED, THE CROSS BAR SHALL BE SELECTED AT THE DISCRETION OF THE MANUFACTURER.

Heavy Welded Gratings

Grating Traffic Conditions

Heavy Welded Gratings

Heavy Welded Gratings

Heavy Welded Gratings

Heavy Welded Gratings

Heavy Welded Gratings

Heavy Welded Gratings

38W4 Load Table

Bridge Decking

Bridge Decking is manufactured by cold-press riveting truss shaped recticuline bars to rectangular bearing bars. The resulting product is an exceptionally durable heavy duty grating with superior stiffness and lateral stability. Bridge decking is often the preferred heavy duty grating for concentrated or stress applications subject to impact and repetitive loads. Common applications include bridge floors, highways, inlets, and airport trench drain covers.

Bridge Decking Grating

Bridge Decking Grating

Continuous Spans

The safe spans indicated for heavy duty gratings and bridge decking in the preceding load tables are based upon simple span calculations. When the grating is properly anchored and the span is continuous over 3 or more supports, the above spans may be increased by a multiple of 1.20.

Embed Frames cast into concrete floors and substructures serve a multitude of purposes that extend the effective life of your completed construction project. Frames form a permanent shield for concrete lead edges and perimeters which are subject to cracking and chipping when left unprotected. During construction, these rigid 1/4" (minimum) thick steel frames expedite forming and provide a welded structure that assures accuracy in the concrete pour. Frames provide a uniform bearing surface for grates or covers, often eliminating rocking or irregular elevations experienced with covers installed on poured concrete. In specifying Indiana Gratings Embed Frames, you are specifying durability, accuracy and economy. (Nail holes are optional and may further expedite installation. If desired, size and location should be specified.)

Bridge Decking Grating

Heavy Welded Gratings

Heavy Welded Gratings

Trench Grating Systems

Trench Grating Systems by Indiana Gratings allow the specifier to combine any of the gratings illustrated above with any of the embed frames profiled on page 14. Gratings are available in Standard series for pedestrian loads or Heavy Duty series for vehicular traffic. Unlike cast iron or molded trench products, this flexible system allows the user to specify the exact clear opening ("S" dimension) desired. Because Indiana Gratings offers five distinct embed frame profiles, the user can select a frame to meet the exact edge condition desired. Bolting the grates to the frames is optional and must be specified. All gratings are provided with plain surface (the optional serrated surface is also available when specified) and open ends are trench banded to maximize drain capacity. Unless otherwise noted, all trench frames and grating are hot dip galvanized after fabrication in accordance with ASTM Specification A-123.

Trench Grating

Trench Grating & Inlet Sets 

Indiana Gratings Trench Grating Systems and Inlet Sets combine our most popular gratings and embed frames to provide economic, modular components for construction projects. These products are offered in our Standard series, designed to serve pedestrian loads, and our Heavy Duty series, designed to service the most demanding vehicular traffic. Each series is offered with multiple bar spacings (shown below) to address the specific needs of your application.

Bolted Grates

Indiana Gratings Trench Systems and Inlet Sets are manufactured as component products with the grates easily removed for clearing debris from the trenches or inlets. Often security concerns or traffic conditions dictate that the grates must be bolted to the framing. When this option is specified, weld lugs or counter-sunk lands (below) are installed on the grates and the bolt is installed below the traffic surface of the grating. For high security applications, bolted grates with tamper-resistant fasteners may be further specified.

Trench Grating

Inlet Grates & Frames

Complimenting our trench grating systems, Indiana Gratings Inlet Gratings and Frames provide the specifier with flexible solutions to inlet drain requirements. Equal to our trench grating products, Standard Duty pedestrian grates and 

Heavy Duty vehicular grates are illustrated on page 15 of this catalog. Inlets may be specified to any clear opening by simply indicating the desired "W" (width) and "S" (span) dimensions illustrated on page 14. Similar to our trench grating systems, any of the five embed frame profiles may be specified to meet the exact
needs of your application. Bolting the grates to the frames is optional and must be specified. While all gratings are manufactured with plain walking surface, the optional serrated surface may be specified. The ends of all inlet gratings are trench banded to enhance durability and allow
for maximum drainage. Unless otherwise specified, all inlet grates and frames are hot dip galvanized in accordance with ASTM specification A-123.

Fasteners & Banding


All grating must be firmly fastened in place. Welding panels to the supporting structure provides a superior, permanent installation. Gratings subject to removal can be fastened with Weld Lugs which are shop welded between the bearing bars, or anchored with Saddle Clips. These fasteners, which are provided upon request, are punched with 5/16" holes to receive 1/4" bolts or screws (bolts or screws supplied by others). In areas where welding or drilling is not permitted, "G" Clips can provide the fastening solution. These clips install on the top surface of the grating and create a friction connection with the flange supporting the panel. The narrow spacing of close mesh gratings allows for countersinking of the bearing bars and fastening with flat head screws.

Banding Weld Standards

Heavy Welded Gratings

Panel Widths & Layout

Grating panels are manufactured in nominal 24" and 36" standard widths. When considering alternative widths, consult the table below to select widths that will maintain consistent out to out spacing of the bearing bars. Widths specified which deviate from the table below can be fabricated utilizing side banding. In so doing, the outside bearing bar spacing on one side of the finished panel will deviate from the spacing throughout the rest of the panel.

Panel Width Chart

Panel Layout 

As stated above, stock grating panels are manufactured in 24" and 36" nominal widths. Stock lengths (span) are 24'-0" for all sizes with most popular bearing bar sizes also available in 20'-0" lengths. These sizes allow for efficient layout and waste minimization when they are fabricated to your exact specification.
Unlike many competing products, individual grating panels do not require supports on all four sides of each cut piece. Bar grating panels only require support perpendicular to the bearing bar span. There is no need to place supports parallel to the bearing bars where adjacent panels are installed in succession.
The following layouts illustrate proper layout and support of a simple bar grating platform.

Panel layouts

Manufacturing Tolerances

Installation Clearances