KENYA STANDARD            DKS 2878:2019 
ICS 
  
 
 
  
 
  
 
 
 
  
 
  
Corrugated Sheet Steel Beams for 
Highway guardrail - Specification 
 
PUBLIC REVIEW DRAFT 2019 
 
 
   
 
  
 
  
 
  
 
  
 
  
 
  
© KEBS 2019 First Edition, 2019 
 
 
  KENYA STANDARD                                          DKS 2878:2019  
ii  © KEBS 2019 — All rights reserved TECHNICAL COMMITTEE REPRESENTATION 
 
The following organizations were represented on the Technical C ommittee:  
 
Ministry of Transport, Infrastructure, Housing and Urban Develo pment - State Department For Infrastructure 
Kenya Police Service 
Consumer Information Network 
University of Nairobi  
Institution of Eng ineers of Kenya  
Kenya Urban Roads  
Engineers Board of Kenya 
Road Safety Association of Kenya 
Kenya National highways Authority 
Matatu Owners Association Kenya Roads Board 
National Transport & Safety Authority  
Material Testing & Research division (MTRD)  
Kenya Institute of Highways Technology 
Abyssinia Group of Companies 
Kenya Bureau of Standards — Secretariat 
 
 
 
 
 
 
 
 
  
 
 
REVISION OF KENYA STANDARDS 
 
In order to keep abreast of progress in industry, Kenya Standar ds shall be regularly reviewed.  Suggestions 
for improvements to published standards, addressed to the Manag ing Director, Kenya Bureau of Standards, 
are welcome. 
  
 
 
© Kenya Bureau of Standards, 2019 
 Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 130 of 2001  of the Laws of Kenya, copyri ght subsists 
in all Kenya Standards and except as provided under Section 25 of this Act, no Kenya Standard produced by Kenya Bureau of Stand ards 
may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing fro m the 
Managing Director. KENYA STANDARD                                           DKS 2878:2019 
ICS  
© KEBS 2019 — All ri ghts reserved   iii   KENYA STANDARD                                          DKS 2878:2019  
iv  © KEBS 2019 — All rights reserved  
 
 
  
 
  
 
 
  
 
Corrugated Sheet Steel Beams for Highway 
guardrail - Specification 
 
 
  
 
  
 
  
 
 
  
 
  
 
  
 
  
 
  
 
  
 
 
  
KENYA BUREAU OF S TANDARDS (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, 223 96       Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448   Fax: (+254 057) 21814 
  KENYA STANDARD                                           DKS 2878:2019 
ICS  
© KEBS 2019 — All rights reserved   v Foreword 
 
This Kenya Standard was prepared by the Roads and Road Furnitur e Technical Committee under the 
guidance of the Standards Projects Committee and in accordance with the procedures of the Kenya Bureau 
of Standards.  DKS 2878 Gives Standard Specification fo r Corrugated Sheet Steel Beams f or Highway guardrail. Its 
characteristics are defined in terms of Classification, Orderin g information, Basis of Acceptance, materials, 
Manufacture, Mechanical Properties, Coating Requirements, Dimen sions and Marking. 
 
In drafting this standard, assistance was sought from the follo wing publications and their use is acknowledged 
with appreciation.   
AASHTO Designation: M180-12(2017). 
 KENYA STANDARD                                   DKS 2878:2019  
7 
  
Standard Specification for Corr ugated Sheet Steel Beams for 
Highway guardrail 
 
  
1. Scope 
  
1.1. This specification covers corrugated sheet steel prepared for u se as beams in highway 
guardrails. 
 
1.2. The values stated in SI units are to be regarded as the standar d. 
  
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 latest 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 Hardwar e 
 T 65M/T 65, Mass [Weight] of Coating on Iron and Steel Article s with Zinc or Zinc-Alloy 
Coatings 
 
2.2. ASTM Standards: 
 A307,  Standard Specification for Carbon Steel Bolts, Studs, a nd 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-C oated  (Galvanized),   or Zinc-
Iron Alloy-Coated  (Galvannealed)  by the Hot-Dip Process 
 B6; Standard Specification for Zinc 
 B695,  Standard Specification for Coatings of Zinc Mechanicall y Deposited on Iron and Steel 
 E376,  Standard Practice  for Measuring Coating Thickness by M agnetic-Field  or Eddy-
Current (Electromagnetic)  Testing Methods 
 F568M, Standard Specification for Carbon and Alloy Steel Exter nally 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 Primer for Steel or Galvanized  Metal  Surfaces 
 
2.5. Military Standard: 
 DOD-P-21035,  Paint,  High Zinc Dust Content, Galvanizing Repa ir (Metric) 
 3. CLASSIFICATION 
  
3.1. Four types and two classes of guardrail are provided as follows : 
 KENYA STANDARD                                   DKS 2878:2019  
 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 nominal 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  f o l l o w i n g   i n f o r m a t i o n ;   a s  
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 an y. 
 
 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 lot if less than 2 00 pieces are included 
therein, for determination of compliance with specification req uirements. If one piece 
fails to meet the requirements, two other pieces shall be teste d.  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 t hat quantity of material 
offered for inspection at one time that bears the same heat and  coating identification. 
 
5.3. Acceptance  by Brand Registration and Guarantee:  
  
5.3.1. By mutual agreement between the fabricator and engineer, accept ance may be based 
on a brand registration and guarantee filed with the engineer b y the fabricator. For 
acceptance of a brand,  the fabricator shall  furnish a brand r egistration and guarantee 
meeting the approval  of the engineer and showing  the brand na me or designation, the 
manner in which it w ill appear on the fabric ated beams,  the ty pical 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 w ill conform ful ly to the requirements of 
the specification and shall be replaced without cost to the eng ineer when found not in 
conformity with any of the specified requirements. The brand re gistration and guarantee 
shall be sworn to for the fabricator by a person having legal a uthority to bind the 
company. Upon approval of a brand registration and guarantee, t hat brand will be KENYA STANDARD                                   DKS 2878:2019  
9 
 accepted without further certification. If, in subsequent  actu al field use, there is evidence 
of misbranding as determined by random sampling and detection o f inadequate tensile 
strength, yield strength, elongation, improper coating,  defici ent thickness, or improper 
fabrication,  the material will be reject ed and approval for fur ther use withdrawn until 
subsequently reapproved. Samples for test of any material offer ed for use may be taken 
at any time deemed desirable by the engineer. 
 
5.3.2. The manufacturer or fabricator shall make such tests and measur ements as necessary 
to ensure that the material produced complies with all specific ation requirements. These 
tests and measurements shall be so identified by the identifica tion symbols 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 fil e and shall be submitted to 
the engineer on request. 
 
5.3.3. The brand shall be removed or obliterated by the manufacturer o r fabricator on all 
material where control tests, as outlined herein, do not show c onformance 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 me tal 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 "Pri me 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 corros ion resistant material 
and conform to or exceed the requirements of ASTM A307. 
 
6.3.3. All connections or splices shall be formed with oval shoulder b utton headed bolts to 
minimize projections on the roadside of the guardrail. Splice a nd post bolts and nuts 
shall conform to one of the configurations shown in Figures 1   or 2. Either of the alternate 
configurations may be furnished unless otherwise specified by t he engineer. 
 KENYA STANDARD                                   DKS 2878:2019  
  
KENYA STANDARD                                                                          
DKS 2878:2019  
© KEBS 2017 — 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 a pply to Alternate   Bolt No. 2.  
 All dimensions are subject to manufacturer's tolerances   exce pt where allowable   tolerances   are 
shown. 
 
Figure 1  - 15.88 mm Post or Splice Bolt and Nut 
 
 
 
  
 
 
 
  
KENYA STANDARD                                          DKS 2878:2019  
  
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 C lass 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 recess  shown   in  the drawing,   shall   co nform  to ANSI  B 18.2.4.1    M Style   I   
for zinc-coated    hex nuts,  and ANSI  BI 8.2.4.6M    heavy-he x   corrosion-resistant     nuts  shall 
conform to the requirements   of ASTM  A563M  for Class   8S3.  Zinc-coated   nuts shall be tapped 
oversize as specified in ASTM A563M,   except that a diametrica l   allowance   of 510   mm shall   be 
used instead of 420mm. 
 Dimensional    tolerances    not  shown   or implied   are int ended  to be those  consistent  with the 
proper  functioning    of the part,  including    its  appearan ce  and  accepted  manufacturing    practices. 
  
 
  
 
 
KENYA STANDARD                                               DKS 2878:2019 
 
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 I V beams shall be of an approved 
corrosion-resistant steel. Backup plates if specified for use a t non-splice points shall consist of 
305-mm sections of beams and shall be of the same class and typ e 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 thicknes s of the metal and the same type 
as the beam to which it is attached, or the engineer may specif y the minimum thickness of the 
metal and type. 
 
 
7. MANUFACTURE  
7.1. The beams and end or buffer sections shall be shaped and punche d  i n  c o n f o r m a n c e  w i t h  t h e  
requirements shown in Figures 3 and 4.  Transition sections sha ll be fabricated in accordance with 
Figure 5 and shall provide a smooth and uniform transition betw een beams.  They shall be ready for 
assembly when delivered.  Only drilling or cutting necessary fo r special connections and for sampling 
will be permitted in the field. Warped or deformed beams will b e rejected. Beams to be erected 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 th e 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  specimens 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 galva nized after fabrication shall 
conform to the requirements of M 111 M/M 111.  Coating and test ing requirements listed under 
M 180 shall govern.  Sampling and testing not listed under M 18 0 shall be conducted in 
accordance with th e referenced coating specification. 
 
9.1.2. The mass of coating shall conform to the requirements prescribe d in Table 1   for the types 
specified.  The mass of coating is the total amount of galvaniz ing on both sides of a sheet or 
beam, expressed as grams per square meter (ounces per square fo ot) of the sheet or beam. 
 KENYA STANDARD                                          DKS 2878:2019  
  
 
 
  
 
  
 
 
  
KENYA STANDARD                                                                                        DKS 2878:2019  
© KEBS 2017 — All rights reserved   i 
KENYA STANDARD                                                                                        DKS 2878:2019  
© KEBS 2017 — All rights reserved   i 
KENYA STANDARD                                                                                        DKS 2878:2019  
© KEBS 2017 — All rights reserved   i 
KENYA STANDARD                                                                          
DKS 2878:2019  
© KEBS 2017 — All rights reserved   i  
9.1.3. The sheets or beams shall be of prime finish, that is, free fro m injurious defects such as blisters, 
flux, and uncoated spots.  Uncoated edges resulting from transv erse shearing or punching of 
holes will not be considered objectionable. 
 
9.1.4. The coating shall be smooth, free of beading or sharp projectio ns along the edges, and shall 
adhere tenaciously to the surface of the metal. The adherence o f 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 o f 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, mater ial may be accepted on the basis 
of magnetic gauge determinations made in accordance with ASTM E 376. 
 
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 s hall 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 galv anized.  They shall be so handled 
and stored that the traffic face of these beams, used in a cont inuous 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 z inc coated in accordance with the requirements of M 232M/  
M 232, Class C or mechanically zinc-coated in accordance with A STM B695, Class 50, Type 1. 
 
9.5. Washers: 
 
9.5.1. Washers shall be hot-dip zinc-coated in accordance with the req uirements 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 conf orm to the requirements as 
prescribed in Table 2. KENYA STANDARD                                                                                        DKS 2878:2019  
© KEBS 2017 — All rights reserved   i 
 
KENYA STANDARD                    DKS 2878:2019 
 
 
© KEBS 2019 — All rights reserved   1  
10.1.2. For fabricated beams, thickness measurements will be made on ta ngent portions of the cross 
section. 
 
10.2. Sheet Width: 
 
10.2.1. The beam elements shall be formed from sheets having nominal wi dths of 483 mm for W-
beams and 749 mm for thrie beams. Tolerance from the nominal wi dth 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 dimensio ns of Figures 3 and 4 can be 
met within allowable tolerance by using the nominal widths.  Us e of sheets slightly greater than 
the nominal widths is permissible provided the tolerances in Fi gures 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. Marki ngs placed on the traffic face of the 
beam shall be placed in the valley of the centre corrugation an d shall be die-imprinted with letters 
and numerals having a maximum height of 32 mm and a minimum hei ght 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, transportation, and erection. 
 
11.4. Markings for end sections and backup plates may be on durable t ags securely attached to each 
section or bundle, except that when specified by the engineer, each individual piece shall be marked.