Faster, Better & Cheaper
Infrastructure Solutions

Benefits of Specifying Corrugated Steel

Consider the many benefits of specifying corrugated steel products:

Material Specification

The raw material shall be tested and the cast analysis values shall conform to the following.

Chemical Composition

Mechanical Properties

Yield Strength

230 MPa (Minimum)

Elongation

16% minimum on 200 mm gauge length

Anti-corrosion coating

Hot-dip galvanized, 610 g/m²

Features

Correct installation procedures will ensure maximum performance. The interaction of a well-compacted engineered backfill with the superior section properties of corrugated steel plate ensures a structure capable of supporting high loads with the most economical use of steel.

Factors Affecting Durability

Durability in soil is a function of several interacting parameters including soil resistivity, acidity (pH), and moisture content. The higher the resistivity, the greater the durability.

Flow Conditions and Definitions

Before designing culverts, storm sewers, and other drainage structures, one should consider the design of ditches, gutters, chutes, median swales, and other channels leading to these structures. Culverts considered here are circular pipes and pipe-arches with a uniform barrel cross section throughout.

Detail Product

Nestable Flange E-100 is the most common and versatile of the corrugated steel pipe shapes. It is used primarily for culverts and small bridges, but is also appropriate for storage bins, stormwater drains, and sub-drains.

The information in this brochure should be checked in detail by the professional engineer responsible for the design to verify its accuracy; also, the assumption and methods used to obtain the information should be reviewed to make certain they are applicable and suitable for the design.

Section Properties

Design Service

We offer an obligation-free professional design service for the application of Nestable Flange E-100. The service includes but is not limited to: structural design, hydraulic design, construction advice and details, durability advice, assembly drawings, and installation guidelines. Structures are custom designed to meet the required clearance requirements or hydraulic waterway area.

Structural Review Methods

• Module calculation
• Based on AASHTO, ASTM, AS, and SNI — depending on client need
• Finite Element Analysis
• Guidelines for selection of hydraulics, traffic / pedestrian passage, or grade separation structure

Structural Design Sequence

• General structure selection
• Additional selection consideration — refining structure selection
• Check service life and protection from environment (effects, design life, material selection — galvanized steel or aluminum, aggressive environments, de-icing salts)
• Check structure hydraulics — hydraulic checks, hydraulics of corrugated metal structures, tools for hydraulic analysis, scour analysis
• Check structural design — structural checks, design methods, material properties
• Specify bedding, backfill and check foundation — soil envelope, bedding, foundation requirements, backfill envelope & recommendations
• Structure end treatment — bevels, skews, headwalls, toe-walls and cutoff walls

Installation Guide

Nestable Flange E-100, due to its strength, light weight, and resistance to fracture, can be installed quickly, easily, and with the least expensive equipment.

Unloading and Handling

Although Nestable will withstand rough handling without deformation, they should be handled with reasonable care. Nestable should never be dumped directly from a truck bed while unloading, but should be lifted or rolled to protect the galvanized surface. Dragging the structures at any time may damage the coatings and jeopardize durability. Avoid striking rocks or hard objects when lowering pipe into trenches.

Assembly

Before starting to assemble the structure, study the site-specific General Arrangement Drawing supplied by PT.GAS, paying particular attention to the details showing the orientation of the plates and the stagger of the joints, as these are vitally important. Plates are not symmetrical and must be oriented correctly.

The laying sequence shown on the Plate Layout Detail on the drawing is suggested to minimize the possibility of misalignment of the structures. For short structures the full length of bottom plates is laid in the first stage and stage two effectively completes the structure if the assembly sequence is followed through.

During assembly, connect the bottom and top plates with as few bolts as possible. Insert sufficient bolts to hold the plates in position, but do not over-tighten the nuts. Loose bolting leaves the plates free to move slightly, which eases matching the remaining bolt holes. About three plate rings behind assembly, insert the remaining bolts. Start at the center of the plates and work towards the corners. When all bolts are inserted, tighten nuts to the specified torque.

Base Preparation

For standard installation it is recommended that the width of the foundation be at least three times the diameter of the Nestable, and be free of rocks, mud, water, stumps, and organic or frozen material. A properly installed base will facilitate proper alignment and grade of the Nestable during installation and the subsequent service life of the application.

The bedding blanket is a thin layer of loosely placed granular material (less than 35% fines) that cushions the pipe invert and allows the corrugation to nest or seat into it. A well-graded granular material containing rock fragments as large as 75 mm will allow the pipe to settle into the bedding in this fashion.

Backfilling

A well-graded granular backfill that is at least 150 mm in depth is recommended for the bedding. Poor soil conditions or granular material necessitate a more substantial base under the Nestable. The use of a geotextile material is common to provide soil strength and separation.

1 · Multi-Plate Pipe

Used for culverts, storm sewers, aggregate tunnels, vehicular and pedestrian tunnels, and stream enclosures. Functions well in all applications, but especially in those with high cover.

2 · Multi-Plate Pipe Arches

Limited headroom. Has hydraulic advantages at low flow levels. Used for culverts, storm sewer, underpass, and stream enclosures.

3 · Multi-Plate Arches

Low clearance, large waterway opening. Aesthetic shapes and open natural bottoms for environmentally-friendly crossings.

4 · Multi-Plate Underpass

Offers an efficient shape for passage of pedestrians or livestock, vehicular traffic, and bicycles with minimal buried invert.

5 & 6 · Multi-Plate Horseshoe Arch (HA & EA)

Railroad underpasses or large clearance areas. Type EA offers a higher rise for larger clearance needs.

7 & 8 · Multi-Plate Horizontal & Vertical Ellipse

Wide span options for larger culverts and bridges with controlled waterway geometry.

1 · Multi-Plate Super Span Horizontal Ellipse

Larger culverts and bridges. Low headroom, wide-centered flow, good choice when poor foundations are encountered.

2 · Multi-Plate Super Span High Profile Arch

Culverts, storm sewers, bridges. Higher rise, large area opening. Open natural bottoms for environmentally friendly crossings.

3 · Multi-Plate Super Span Low Profile Arch

Culverts, storm sewers, low headroom and large opening. Bridge structures, stream enclosures. Aesthetic shapes and open natural bottoms for environmentally friendly crossings.

4 & 5 · Multi-Plate Super Span Pear Arch & Pear Shape

Railroad underpasses or large clearance areas. The Pear Arch and Pear Shape offer generous headroom with streamlined waterway sections.

6 · Multi-Plate Nova Span Profile Arch

Culverts, storm sewers, low headroom and large opening. Bridge structures, stream enclosures. Aesthetic shapes and open natural bottoms for environmentally friendly crossings.

Design Process

If designed properly, the combination of structural steel and surrounding soil allows Multi-Plate to support extremely heavy loads. However, design assistance and recommendations can be specified to suit your project. Contact our Products Technical Sales Representative for assistance.

1. Check minimum allowable cover — the largest of:
   • 0.6 m (refer to project specification)
   • (D_h/6) · (D_h/D_v)^1/2
   • 0.4 · (D_h/D_v)²
2. Calculate dead-load thrust T_D = 0.5 (1.0 – 0.1 C_s) A_f W
3. Calculate live-load thrust — the lesser of:
   T_L = 0.5 D_h σ_L m_f    or    T_L = 0.5 L_t σ_L m_f
4. Earthquake thrust T_E = T_D · A_v
5. Total thrust:
   T_f = α_D · T_D + α_L · T_L · (1 + DLA)
   T_f = α_D · T_D + T_E = (α_D + A_v) · T_D
6. Calculate the compressive stress
7. Calculate the wall strength in compression
8. Check wall strength requirements during construction
9. Check wall strength of completed structures with deep corrugations
10. Check seam strength & difference in plate thickness of adjacent plates
11. Check plate radius of curvature

Variable Definitions

Soil Stiffness Reference

Base Preparation

Pressure developed by the weight of the backfill and live loads is transmitted both to the side fill and the strata underlying the pipe. The supporting soil beneath the pipe, generally referred to as the foundation, must provide both longitudinal and lateral support. The portion of the foundation in contact with the bottom of the structure is referred to as the bedding. Depending upon the size and type of structure, the bedding may either be flat or shaped.

Unloading & Handling

Corrugated steel structures are relatively lightweight and can be handled with light equipment. CSP should never be dumped, dragged, or unloaded in a manner that would damage the coating or alter the shape of the CSP. Premature corrosion can start around the damage area if not repaired.

Plates for structural plate structures are shipped nested in bundles, complete with all plates, bolts, and nuts necessary for erection. Included with the shipment are detailed erection drawings showing the order of assembly and the position of each plate.

Pre-sorting the plates as they are unloaded, on the basis of their radius and location in the structure, is important. All plates are clearly identified so that they can be easily sorted.

Bolt Torque Specification

Assembly Methods

There are four basic methods by which structural Multi-Plate can be assembled:

Backfilling & Critical Zone

The first 1.5 m above the structure requires careful handling. Backfill must be placed in balanced lifts on both sides, with strict moisture and compaction control.

Backfill Material Specification

Trench & Embankment Installation

Shape Control

Shape control refers to controlling the symmetry of the structure during backfill, by control of the backfill operation. As a general rule, deflection in any direction measuring greater than 2% from original shape should not be allowed during the backfill operation. The sides of a flexible structure will naturally push outward, compacting the side fills and mobilizing their passive resistance. As the sides go outward, the top moves downward. This downward vertical small is normal.

Nova Span Concrete Cap

The design of the concrete cap reinforcement layout is supplied by PT.GAS.

Introduction

Roadside barriers have been developed over the years to safely redirect vehicles that leave the roadway. Many different rigid, semi-rigid, and flexible designs for roadside barriers have evolved. The most common system consists of a steel W-beam rail supported on steel posts with end treatments and transitions of various designs using similar materials.

Our Civil Products' Flex-Beam guardrail's uniformly high resistance to impacts is assured by its continuous flexible beam action. This prevents dangerous pocketing and minimizes the ride-down deceleration experienced by the vehicle and its occupants.

The high visibility of Flex-Beam guardrail creates driver confidence — an intangible but exceedingly important factor. At night or in fog conditions, the excellent visibility of Flex-Beam guardrail highlights the limit of safe travel and reduces dangerous center-line crowding.

The pipe railing is built as a standard profile to keep the price low. The design focuses on aesthetics so our pipe railing is mostly used where the demands for attractive and see-through product are high — for example close to traffic interchanges, rivers, or cultural sites. Because of its closed profile and ingenious mount, Pipe railing is the simplest and quickest pipe railing to install. The post fastening bolt is already fitted on delivery, reducing assembly time.

Specification & Cross Section

Barrier Deflection

The expected deflection of the barrier should not exceed the available room to deflect. If the available space between the hazard and the barrier is not adequate, then the barrier can be stiffened in advance of, and alongside, the hazard. Commonly used methods to reduce deflection of Flex-Beam guardrail include reducing the post spacing.

End Terminals & Transitions

Guardrail end terminals are designed to provide a soft gating impact to prevent the end rail from spearing an impacting vehicle. Terminals also introduce tensile and flexural strength necessary to ensure redirection performance of the length-of-need section.

Transitions are required when Flex-Beam guardrail is terminated at a bridge abutment or a concrete parapet. The purpose of a transition is to smoothly increase the stiffness of the approach guardrail from the more flexible to the less flexible system.

Installation

a · Site Preparation

Flex-beam guardrail should be located at least 600 mm (measured from back of post) in front of embankments that require shielding. This distance is required to provide proper post support. The approach terrain to the barrier must be level. Grading to 1:20 is preferable and 1:10 maximum slope should be present. Steeper slopes can result in the vehicle impacting the barrier at other than the design height.

b · Curving

FLEXBEAM guardrail may be shop-curved to fit any radius from 2.4 m to 46 m. Curves in excess of 46 m radii do not require shop curving as the lap joint accommodates itself to such installations. Rail may be curved either concave or convex to the traffic face and can be part-curved along its length to suit your needs.

Measuring Curvature

1. Depending on your length of rail, mark along your arc at 4 m interval.
2. Measure the corresponding chord length (C) — refer to the figure.
3. Measure the corresponding center offset (H) — refer to the figure.
4. Use the values for C and H to select the radius from the table.
5. Determine the curvature orientation from the figure.

c · Installation Sequence

1. Ensure the area has been inspected for underground hazards and that suitable traffic control is in place.
2. Post locations are marked ensuring the hazard to be protected is located outside the expected dynamic deflection of the barrier.
3. The post is orientated with no post edges presented towards the traffic.
4. Posts are driven directly into the ground and should be vertical. (The post installation process shall not cause damage to the post, such that it reduces the effective operation of the safety barrier or its design life, or introduces sharp tearing edges, nor shall it cause damage to pavement.) Alternately, a hole can be augured and the post placed in the hole.
5. Continue with rail alignment, splice bolting, and post fastening per the standard sequence.

Bridge Pipe Railing

Bridge pipe railing passes the test for the highest performance class. This parapet has two pipes based on a standard profile.

The parapet is airy and aesthetically pleasing, and for that reason it is used where there is a requirement for a tastefully-designed traffic environment with good overall visibility — for example, at traffic interchanges, water conservation areas, bridges over railways, watercourses, or cultural sites.

Installation on Bridge

1. Safety-walks range in width from 450 mm to less than 1,200 mm. On existing freeway and interstate structures with safety-walks, where it is not feasible to remove the safety-walk and provide a concrete, barrier-shaped parapet, the pipe railing shall be carried across the structure along the gutter line. However, on existing freeway and interstate ramps where the posted speed or advisory speed is 40 mph or less and the safety-walk is 750 mm or less in width, it is not necessary to carry guide rail across the structure since vaulting is not likely to occur.
2. Where the roadway approaching a structure has curbs or berms, the pipe railing mounting height on the structure should be measured from the top of curb and a rub rail is required. However, on long structures, the pipe railing mounting height may be measured from the gutter line provided the face of pipe railing is flush with the curb face. In this case, rub rail will not be required. The pipe railing mounting height should be measured from the gutter line on those structures where the approach roadway is an umbrella section and the face of pipe railing is set flush with the curb face on the structure. Where guide rail is set flush with the curb face and the mounting height is measured from the gutter line, rub rail is not required.
3. Where there is a difference in the offset to the approach pipe railing and the offset to the bridge parapet, the approach pipe railing should be flared at 15:1 prior to the standard pipe railing transition to the bridge parapet.
4. Attachment of pipe railing to bridges and structures shall be in accordance with the Department's Standard Roadway Construction Details, revised or modified Standard Details, or Special Details. The designer shall specify at each location on the construction plans the pipe railing attachment detail to be used.
5. Where there is considerable pedestrian traffic, the pipe railing may be set flush to the curb face to physically separate the sidewalk from the roadway.

Introduction

Our street lighting columns are designed and manufactured for durability, corrosion resistance, and visual appeal. We begin with the highest-quality materials for our steel designs to fabricate poles and supports that meet your specifications and exceed your expectations for street lighting and a number of other applications.

Technical Specification

Single Ornament — Parabola & T

Double Ornament — Parabola & T

Installation

The lighting pole shall be provided with 4 "L-Type" anchor bolts. For anchor bolt minimum diameter, length, and projection details, see the tables above. Each anchor bolt shall be supplied assembled with (2) nuts, (2) flat washers, and (1) split lock washer. All anchorage hardware shall be partially galvanized.

Custom Design

The ingenious and effective use of Corrugated Steel Pipe in a diverse range of applications is testimony to the product's versatility. Urban development, confined spaces, and time pressures have led to the necessity for fast construction methods that minimize the need for curing of in-situ concrete construction. The unique prefabricated design versatility offered by Corrugated Steel Pipe increases the scope of possible solutions and provides an edge for competitive civil construction.

Corrugated Steel can be manufactured to incorporate the following special features:

Complete Installation Service

PT. GAS provides complete installation services for all corrugated steel structures, including Multi-Plate, Nestable Flange E-100, guardrail, and pipe railing systems. Our experienced installation crews work to PT.GAS standards and the project-specific drawings, ensuring every structure is built to specification and to last.