KENYA STANDARD             DKS 296 2-2022  
ICS 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Standard Specification for Corrugated 
Sheet Steel Beams for Highway guardrail  
 
PUBLIC REVI EW DRAFT 2022  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
© KEBS 2 022 First Edition , 2022 
 
 
  DKS 296 2-2022  
ii  © KEBS 20 22 — All rights reserved  TECHNICAL COMMITTEE REPRES ENTATION  
 
The following organizations were represented on the Technical Committee:  
 
Kenya Urban Roads Authority  
Asphalt Institute of East Africa Ltd  
Kenya National Highways Authority  
Roads Division, State Department of Infrastructure, Ministry of Transport, Infrastructure, Housing, Urban 
Developme nt and Public Works  
Kenya Builders & Concrete Company Limited  
University of Nairobi  
Pelican Signs Ltd  
State Department of Public Works, Ministry of Transport, Infrastructure, Housing, Urban Development and 
Public Works  
Zed Axis Limited  
TradeMark East Afric a 
Institution of Engineers of Kenya  
Kenya Roads Board  
Egis Kenya - Engineering Consultants  
Lesma Engineering Ltd.  
Kenya Rural Roads Authority  
Nairobi Western Bypass project  
Dedan Kimathi University of Technology  
 
 
 
 
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed.  Suggestions 
for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are welcome.  
 
 
 
 
© Kenya Bureau of Standards, 20 22 
 
Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 130 of 2001  of the Laws of Kenya, copy right subsists 
in all Kenya Standards and except as provided under Section 25 of this Act, no Kenya Standard produced by Kenya Bureau of Standards 
may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing f rom the 
Managing Director.  
  KENYA STANDARD                                       DKS 2962 -2022  
ICS  
© KEBS 20 22 — All rights reserved    iii  
 
 
 
 
 
 
 
 
 
 
 
 
Standard Specification for Corrugated Sheet 
Steel Beams for Highway guardrail  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office: P.O. Box 54974, Nairobi -00200, Tel.: (+254  020) 605490, 602350, Fax: (+254 020)  604031  
E-Mail: info@kebs.org, Web:http://www.kebs.org  
 
Coast Region     Lake Region      Rift Valley Region  
P.O. Box 99376, Mombasa -80100   P.O. Box 2949, Kisumu -40100        P.O. Box 2138, Nakuru -20100  
Tel.: (+254  041) 229563, 230939/40  Tel.: (+254 057) 23549, 22396        Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448    Fax: (+254 057) 21814  DKS 296 2-2022  
iv  © KEBS 20 22 — All rights reserved    KENYA STANDARD                                       DKS 2962 -2022  
ICS  
© KEBS 20 22 — All rights reserved    v  
Foreword  
 
This Kenya Standard was prepared by the Roads and Road Furniture Technical Committee under the 
guidance of the Standards Projects Committee and in accordance with the procedures of the Kenya Bureau 
of Standards . 
 
CD/ENG/0 9/2017  Gives Standard Specification for Corrugated Sheet Steel Beams for Highway guardrail . Its 
characteristics are defined in terms of Classification, Ordering information, Basis of  Acceptance, materials, 
Manufacture, Mechanical Properties, Coating Requirements, Dimensions and Marking.  
 
In drafting this standard, assistance was sought from the following publications and their use is acknowledged 
with appreciation.  
 
AASHTO Designatio n: M180 -12(2017).  
  
7 
  
Clay Masonry units — Specification  
 
 
 
1. Scope  
 
 
1.1. This specification covers corrugated sheet steel prepared for use as beams in highway 
guardrails.  
 
1.2. The values stated in SI units are to be regarded as the standard.  
 
 
2. Normative references  
 
The  following  referenced  documents  are  indispensable  for  the  application  of this  document.  For 
dated references, only the edition cited applies.  For undated references, the lates t edition of the   
referenced document (including any amendments) applies  or EQUIVALENT KENYAN STANDARD . 
 
2.1. AASHTO Standards:  
❖ M 111 M/M 111, Zinc (Hot -Dip Galvanized) Coatings on Iron and Steel Products  
❖ M 232M/M 232, Zinc Coating (Hot -Dip) on Iron and Steel Hardware  
❖ T 65M/T 65, Mass [Weight] of Coating on Iron and Steel Articles with Zinc or Zinc -Alloy 
Coatings  
 
2.2. ASTM Standards:  
❖ A307,  Standard Specification for Carbon Steel Bolts, Studs, and Threaded Rod 60 000 psi  
Tensile Strength  
❖ A563M,  Standard Specification for Carbon and Alloy Steel Nuts (Metric)  
❖ A653/ A653M, Standard Specification  for Steel  Sheet,  Zinc -Coated  (Galvanized),   or Zinc -
Iron Alloy -Coated  (Galvannealed)  by the Hot -Dip Process  
❖ B6; Standard Specification for Zinc  
❖ B695,  Standar d Specification for Coatings of Zinc Mechanically Deposited on Iron and Steel  
❖ E376,  Standard Practice  for Measuring Coating Thickness by Magnetic -Field  or Eddy -
Current  (Electromagnetic)  Testing Methods  
❖ F568M, Standard Specification for Carbon and Alloy Steel Externally Threaded Metric  
Fasteners (withdrawn 2012)  
 
2.3. ANSI Standards:  
❖ B 1.13M,  Metric  Screw Threads D M Profile  
❖ B18.2.4.1M, Hex Nuts, Style  1,  Metric  
❖ B18.2.4.6M,   Hex Nuts, Heavy, Metric  
 
2.4. Federal Standard:  
❖ TT-P-641,   Type II Zinc Dust Pr imer for Steel or Galvanized  Metal  Surfaces  
 
2.5. Military Standard:  
❖ DOD -P-21035,  Paint,  High Zinc Dust Content, Galvanizing Repair (Metric)  
 
3. CLASSIFICATION  
  
3.1. Four types and two classes of guardrail are provided as follows:  
 
3.1.1.  Types:  
❖ Type I -Zinc-coated, 550 g /m2 minimum single -spot.   
 ❖ Type II -Zinc-coated, 1100  g/m2 minimum single -spot.  
❖ Type III -Beams to be painted.  
❖ Type IV -Beams of corrosion -resistant steel.  
 
 
 
3.1.2.  Classes:  
❖ Class A -Base metal nomin al thickness -2.67 mm . 
❖ Class B -Base metal nominal  thickness -3.43 mm . 
 
 
4. ORDERING INFORMATION  
  
4.1. Orders for guardrail under this specification shall include the following  information;  as 
required, to adequately describe the desired material:  
 
4.1.1.  Quantity (linear meter or number of pieces), Class of guardrail , 
 
4.1.2.  Type of guardrail,  
 
4.1.3.  Effective length of beam section 3.8   or 7.6  m ,  
 
4.1.4.  Shape (W -beam or thrie  beam), and  
 
4.1.5.  Exceptions to this specification or special requirements, if any.  
 
 
5. BASIS OF ACCEPTANCE  
  
5.1. All material shall be subject to inspection and sampling at the fabricating plant, warehouse, 
or after delivery to the site of construction.  
 
5.2. Acceptance  by Sampling:  
 
5.2.1.  The engineer  may take one piece of guardrail,  a backup plate, and end or buffer section 
from each  200 pieces in a lot,  or from each l ot if less than 200 pieces are included 
therein, for determination of compliance with specification requirements. If one piece 
fails to meet the requirements, two other pieces shall be tested.  If either of these pieces 
fails to conform to the requirements  of this specification, the lot of material represented 
by these samples shall be rejected. A lot shall be considered that quantity of material 
offered for inspection at one time that bears the same heat and coating identification.  
 
5.3. Acceptance  by Brand Re gistration and Guarantee:  
  
5.3.1.  By mutual agreement between the fabricator and engineer, acceptance may be based 
on a brand registration and guarantee filed with the engineer by the fabricator. For 
acceptance of a brand,  the fabricator shall  furnish a brand  registration and guarantee 
meeting the approval  of the engineer and showing  the brand name or designation, the 
manner in which it will appear on the fabricated  beams,  the typical mechanical 
properties,  chemical composition if specified,  the class and  type of guardrail,  and other 
specified properties. The fabricator shall also guarantee that as long as  material is 
furnished under that brand and designation, it will conform fully to the requirements of 
the specification and shall be replaced without co st to the engineer when found not in 
conformity with any of the specified requirements. The brand registration and guarantee 
shall be sworn to for the fabricator by a person having legal authority to bind the 
company. Upon approval of a brand registration and guarantee, that brand will be 
accepted without further certification. If, in subsequent  actual field use, there is evidence 
of misbranding as determined by random sampling and detection of inadequate tensile  
9 
 strength, yield strength, elongation, impro per coating,  deficient thickness, or improper 
fabrication, the material will be rejected and approval for further use withdrawn until 
subsequently reapproved. Samples for test of any material offered for use may be taken 
at any time deemed desirable by th e engineer.  
 
5.3.2.  The manufacturer or fabricator shall make such tests and measurements as necessary 
to ensure that the material produced complies with all specification requirements. These 
tests and measurements shall be so identified by the identification sym bols or code used 
on the beam that the manufacturer can produce specific reports showing these test 
results.  Copies of reports of these tests shall be  kept on file and shall be submitted to 
the engineer on request.  
 
5.3.3.  The brand shall be removed or obliterated by the manufacturer or fabricator on all 
material where control tests, as outlined herein, do not show conformance to this 
specification.  
 
6. MATERIALS  
  
6.1. Base Metal  - The beam, transition, end, and buffer sections shall consist of sheet made of 
open hearth, electric furnace, or basic oxygen steel and shall meet the mechanical properties 
specified in Section 8. The chemical composition of the base metal for Type IV beams shall 
be as approved by the engineer.  
 
6.2. Zinc -The zinc used for the coating of Type I and II sections shall be as prescribed in ASTM 
B6, and shall be at least equal to the grade designated as "Prime Western."  
 
6.3. Bolts and Nuts:  
 
6.3.1.  Unless otherwise specified, bolts and nuts for Types I, II, and III  beams shall conform to 
or exceed the requirements of ASTM A307 and shall be coated in accordance with 
Section 9.4.  
 
6.3.2.  Bolts and nuts for Type IV beams shall be of an approved corrosion resistant material 
and conform to or exceed the requirements of ASTM A30 7. 
 
6.3.3.  All connections or splices shall be formed with oval shoulder button headed bolts to 
minimize projections on the roadside of the guardrail. Splice and post bolts and nuts 
shall conform to one of the configurations shown in Figures 1   or 2. Either of t he alternate 
configurations may be furnished unless otherwise specified by the engineer.  
  
  
KENYA STANDARD                                                                                                                                
DKS 2962 -2022  
 
© KEBS 20 22 — All rights reserved    i  
 
 
 
Note:   
❖ Oval shoulder    shall have smooth radii and shall maintain an essentially full vertical   height of the 
apex of the oval.  
❖ All dimensions    shown on Alternate Bolt   No.  1      also apply to Alternate   Bolt No. 2.  
❖ All dimensions are subject to manufacturer's tolerances   except where allowable   tolerances   are 
shown.  
 
Figure 1  - 15.88 mm Post or Splice Bolt and Nut  
 
 
 
 
 
 
 
 
 
 
 
  
Figure 2  -16-mm Post or Splice Metric Bolt and Nut  
 
Notes:   
❖ The bolt shall   have M 16 x 2 threads   as defined in ANSI BI. I 3M for Grade 6 g tolerances.    Bolt 
material   shall conform to ASTM F568M (withdrawn 2012)   for Class 4.6.   Material for  corrosion 
resistant   bolts shall   conform to ASTM F568M for Class   8.8.3    bolts.  
❖ Nuts   shall have ANSI BI.  I 3M M 16   x 2 Grade 6H threads.   The geometry  of the nuts,   with the 
exception  of the r ecess  shown   in  the drawing,   shall   conform  to ANSI  B 18.2.4.1    M Style   I   
for zinc -coated    hex nuts,  and ANSI  BI 8.2.4.6M    heavy -hex   corrosion -resistant     nuts  shall 
conform to the requirements   of ASTM  A563M  for Class   8S3.  Z inc-coated   nuts shall be tapped 
oversize as specified in ASTM A563M,   except that a diametrical   allowance   of 510   mm shall   be 
used instead of 420mm. 
❖ Dimensional    tolerances    not  shown   or implied   are intended  to be those  consistent  wit h the 
proper  functioning    of the part,  including    its  appearance  and  accepted  manufacturing    practices.  
 
 
 
 
 
 
 
DKS 2962 -2022  
 
iii 
  
 
 
6.4. Washers and Backup Plates:  
 
6.4.1.  Washers shall be rectangular as shown in Figure 3.  Washers for Types I, II, and III beams shall 
be galvanized in accordance with Section 9.  Washers for Type IV beams shall be of an approved 
corrosion -resistant steel. Backup plates if specified for use at non -splice points shall consist of  
305-mm sections of beams and shall be of the same class and  type specified for the full -length 
beams.  
 
6.5.  End or Buffer Sections:  
 
6.5.1.  End or buffer sections shall be of the same or greater thickness of the metal and the same type 
as the beam to which it is attached, or the engineer may specify the minimum thickness of the 
metal and type.  
 
 
7. MANUFACTURE  
 
7.1. The beams and end or buffer sections shall be shaped and punched in conformance with the 
requirements shown in Figures 3 and 4.  Transition sections shall be fabricated in accordance with 
Figure 5 and shall provide a smooth an d uniform transition between beams.  They shall be ready for 
assembly when delivered.  Only drilling or cutting necessary for special connections and for sampling 
will be permitted in the field. Warped or deformed beams will be rejected. Beams to be erecte d on a 
radius of 46 m or less shall be shop -curved to the appropriate curvature of the installation.  
 
 
8. MECHANICAL PROPERTIES  
   
8.1. The mechanical properties of the base metal shall conform to the following  requirements:  
 
8.1.1.  Beams and Transition Sections:  
❖ Yield point , minimum,  345 MPa ; 
❖ Tensile  strength ,  minimum 483 MPa ; and  
❖ Elongation,   in  50 mm , minimum, 12 percent.  
 
8.1.2.  End and Buffer Sections:  
❖ Yield  point,  minimum,  227 MPa ;  and  
❖ Tensile strength, minimum 310 MPa.  
 
8.1.3.  Test specimens for mechanical properties shall be prepared and tested as specified in ASTM 
A653/ A653M except that correction for thickness of zinc -coated specime ns shall be 0.08 mm  
for Type I beam and 0.15 mm for Type II beam.  
 
 
9. COATING REQUIREMENTS  
  
9.1. Type I and II Beams:  
 
9.1.1.  The beams may be galvanized before or after fabrication.  Beams galvanized before fabrication 
shall be coated in accordance with ASTM A653/A653M. Beams galvanized after fabrication shall 
conform to the requirements of M 111 M/M 111.  Coating and testing requirements  listed under  
M 180 shall govern.  Sampling and testing not listed under M 180 shall be conducted in 
accordance with the referenced coating specification.  
  
 9.1.2.  The mass of coating shall conform to the requirements prescribed in Table 1   for the types  
specified.  The mass of coating is the total amount of galvanizing on both sides of a sheet or 
beam, expressed as grams per square meter (ounces per square foot) of the sheet or beam.  
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA STANDARD                                                                                                                                DKS 2962 -2022  
 
© KEBS 20 22 — All rights reserved    i 
KENYA STANDARD                                                                                                                                DKS 2962 -2022  
 
© KEBS 20 22 — All rights reserved    i 
KENYA STANDARD                                                                                                                                DKS 2962 -2022  
 
© KEBS 20 22 — All rights reserved    i 
KENYA STANDARD                                                                                                                                
DKS 2962 -2022  
 
© KEBS 20 22 — All rights reserved    i  
9.1.3.  The sheets or beams shall be of prime finish, that is, free from injurious defects such as blisters, 
flux, and uncoated spots.  Uncoated edges resulting from transverse shearing or punching of 
holes will not be considered objectionable.  
 
9.1.4.  The coating shall be smooth, free of beading or sharp projections along the edges, and shall 
adhere tenaciously to the surface of the metal. The a dherence of the zinc coating to the surface 
of the base metal shall be determined by cutting or prying with a stout knife, applied with 
considerable  pressure in a manner tending to remove a portion of the coating by paring or 
whittling, and it shall not be  possible to peel any portion of the coating so as to expose the base 
metal.  
 
9.1.5.  The test specimen size and method of tests for determining the mass of coating shall be as 
prescribed in T 65M/T 65.  At the option of the engineer, material may be accepted on t he basis 
of magnetic gauge determinations made in accordance with ASTM E376.  
 
9.2. Type III Beams:  
 
9.2.1.  Beams that are to be painted shall be cleaned and shop -painted with one coat of rust -inhibitive 
primer. The primer shall have a tough and durable surface and sha ll be thoroughly dry before 
the sheets are handled or packed for shipment.  
 
9.3. Type IV Beams:  
 
9.3.1.  Beams of corrosion -resistant steel shall not be painted or galvanized.  They shall be so handled 
and stored that the traffic face of these beams, used in a continuo us run of guardrail,  shall not 
show a distinctive colour  differential,  
 
9.4. Bolts and Nuts:  
 
9.4.1.  Bolts and nuts shall be hot -dip zinc coated in accordance with the requirements of M 232M/   
M 232, Class C or mechanically zinc -coated in accordance with ASTM B695, Class 50, Type 1.  
 
9.5. Washers:  
 
9.5.1.  Washers shall be hot -dip zinc -coated in accordance with the requirements of  M 232M/M 232.  
 
9.6. Galvanizing Repair:  
 
9.6.1.  Where the galvanizing on guardrail or fittings has been damaged, the coating shall be repaired 
by regalvanizing, or the surface repaired by painting with two coats of zinc dust/zinc oxide paint 
conforming to Federal Specification TT -P-641 or DOD -P-21035.  
 
 
10. DIMENSIONS  
  
10.1.  Sheet or Beam Thickness:  
 
10.1.1.  The nominal thickness for the finished beam or sheet shall conform to the requirements as  
prescribed in Table 2.  KENYA STANDARD                                                                                                                                DKS 2962 -2022  
 
© KEBS 20 22 — All rights reserved    i 
KENYA STANDARD                     DKS 2962 -2022  
 
 
© KEBS 20 22 — All rights reserved    1  
10.1.2.  For fabricated beams, thickness measurements will be made on tangent portions of the cross 
section.  
 
10.2.  Sheet Width:  
 
10.2.1.  The beam elements shall be formed from sheets having n ominal widths of 483 mm  for W-
beams and 749 mm  for thrie  beams. Tolerance from the nominal width of minus  3.2 mm will be 
permissible.  
 
Note 1  –The requirements of Section 10.2.1 are intended to define the minimum width sheet 
permissible. Calculation of exact width dimensions from Figures 3 and 4 shows that the finished 
product may slightly exceed these widths. However, the dimensions of Figures 3 and 4 can be 
met within allowable tolerance by using the nominal widths.  Use of sheets slightly greater than 
the nominal widths is permissible provided the tolerances in Figures 3 and 4 are met.  
 
 
11. MARKING  
   
11.1.  Each beam element shall be identified by the following:  
❖ Name or brand of manufacturer,  
❖ Identification symbols or code for heat,  
❖ Number and coating lot,  
❖ Kebs specification number, and  
❖ Class and type.  
 
11.2.  Markings shall  not be placed at such a location that they will be obscured after erection, or in a 
manner that the brand will be conspicuous to any traffic. Markings placed on the traffic face of the 
beam shall be placed in the valley of the centre corrugation and shall  be die -imprinted with letters 
and numerals having a maximum height of 32 mm and a minimum height of 19 mm , and shall be 
clearly legible after galvanization of the rail elements.  
 
11.3.  Marking material shall be such as to resist obliteration during storage, tra nsportation, and  erection.  
 
11.4.  Markings for end sections and backup plates may be on durable tags securely attached to  each 
section or bundle, except that when specified by the engineer, each individual piece shall  be marked.