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9-17 Flexible Guide Posts9-17 Flexible Guide Posts
9-17.1 General
Flexible guide posts shall be made of a flexible, nonwarping, nonmetallic, durable plastic material; shall be resistant to damage due to impact, ultraviolet light, ozone, hydrocarbons, and other effects of atmospheric weathering; shall resist stiffening with age; and shall be free of burns, discoloration, contamination and other objectionable marks or defects that affect appearance or serviceability. The portion of ground mounted guide post installed below ground may be the same material as the portion above ground or other durable material suitable for firmly anchoring the post in the ground. When iron or steel are used for the in ground portion, galvanize in accordance with AASHTO M111. The top of tubular posts shall be closed to prevent moisture or debris from entering. Surface mounted guide posts shall be mounted on a base made of a rigid high impact resistant material and be resistant to ultraviolet light, ozone, and hydrocarbons. The post shall mount directly into or onto the base in a tamper proof manner and shall allow for easy replacement. Guardrail mounted guide posts shall be the same as ground mounted guide posts except the length shall be adjusted to meet the mounting height requirements in the Standard Plans. Appropriate holes shall be provided for fastening the guide post to the guard rail post. The material composition of flexible guide posts subsequently furnished shall not vary from that of the samples upon which the State Materials Laboratory pre-approval is based. If analysis by the Materials Laboratory determines there is a change in material composition, such change shall constitute grounds for rejection and/or removal from the Qualified Products List. The post system shall be designed for permanent installation to resist overturning, twisting, and displacement from wind and impact forces. Each flexible guide post shall be permanently identified with the manufacturer’s name, and the month and year of fabrication. Ground mounted guide posts shall have a permanent a mark indicating the recommended burial depth. The letters shall be solvent resistant, a minimum of ¼ inch in height, and permanently affixed to the post. Unless otherwise specified, the color of the guide post shall be white or brown as indicated in the Plans. The reflective panel on a flat or elliptical guide post shall have a minimum width of 3 inches facing traffic. The reflective sheeting shall have a minimum area of 24 square inches (3 by 8 inches). The reflective panel on a round guide post shall have an 8-inch minimum band of reflective sheeting visible for 360 degrees.
9-17.1(1) Dimensions
1.Flat Type – The post has a minimum width of 3 inches of continuous flat surface with no curvature for the entire length of the post. This will allow for ridges on the outer edges and back of post intended for structural support.
2.Tubular Type – The post is tubular or round/circular in shape. This allows for a tubular post with a minimum diameter of 3 inches or a tubular post with a minimum diameter of 2 inches with a flat or flattened oval surface at least 3 inches wide and 12 inches long measured from the top for mounting reflective sheeting.
3.Non-flat and Non-Tubular Type – This includes all post that do not fit into the two types indicated above. This would include convex, w-shape, oval, and other post designs. The post shall be wide enough to accept a 3-inch wide reflective sheeting. Any curvature or rounding shall not significantly reduce the brightness value of the reflective sheeting. M 41-10 Page 9-1 17 Flexible Guide Posts 9-174. Surface Mount Guide Post Base – The base for surface mount guide posts shall be approximately 8 inches in diameter with a maximum height of 2 inches.
5.G uide posts shall be of such length to provide the required mounting height above the pavement surface in accordance with the Standard Plans.
9-17.1(2) Reflective Sheeting
Reflective sheeting for guide posts shall be in accordance with Section 9-28.12 . The reflective panel on a flat or elliptical guidepost shall have a minimum width of 3 inches facing traffic. The reflective sheeting shall have a minimum area of 24 square inches (3 by 8 inches). The reflective panel on a round guidepost shall have an 8-inch minimum band of reflective sheeting visible for 360 degrees. Mount the reflective sheeting on the guide post as detailed in the Standard Plans. Sheeting shall remain in place during the life of the post.
9-17.2 Ultraviolet Resistance Test Procedure (Laboratory Test)
Two posts will be tested initially for tensile strength and elongation according to ASTM D638 and again after 1,000 hours QUV weatherometer exposure (ASTM G53). Six bow tie specimens shall be prepared from the delineator post samples submitted for the purpose of ultraviolet (UV) exposure. The specimens shall be cycled at 1,000 hours in a weatherometer in accordance with ASTM G53 (3 hr. 60C UV, 3 hr. 50C CON). Three of each type shall be used for control purposes. The remaining three shall be subjected to 1,000 hours of UV exposure in the QUV weatherometer. Specimen dimensions conform to those outlined below. The laboratory test data shall summarize the tensile strength of each, and the average tensile strength for both control and weathered samples. The data shall also summarize the elongation of each, and the average elongation for both control and weathered samples. The average values shall be used to show the percent change in tensile and elongation.
9-17.2(1) A cceptance
The specimens shall show no signs of delamination, distress, or discoloration. Physical properties of tensile strength and rigidity shall be maintained within 80 percent of the unconditioned values.
9-17.3 Field Impact Test Procedure
Sample size of eight units will be tested the following way: Flexible Ground Mounted PostsEight flexible ground mounted posts installed by the manufacturer (four installed manually and four installed mechanically). The delineators will be hit ten times (four posts for glancing bumper hits and four posts for wheel hits). A standard sedan with a bumper height of approximately 18 inches while traveling at a speed of 55 ± 2 mph will be used for impact testing. Five of the impacts will be at an ambient temperature of 32 ± 5°F and the remaining five impacts at an ambient temperature of 85 ± 5°F. The test vehicle shall impact four of the posts at an angle perpendicular to the front of the post and shall impact the remaining posts at an angle of 25 degrees clockwise from the angle perpendicular to the front of the posts. The same test samples will be used for the ten hits. Two flexible posts will be used for weatherometer testing. A glancing hit is defined as one on the bumper near the vehicle headlight. The delineators shall be installed a minimum of eight hours prior to being hit. Page 9-118 M 41-10
9-17 Flexible Guide PostsFlexible Surface Mounted Posts
Eight flexible surface mounted posts installed by the manufacturer will be hit ten times (four posts for glancing bumper hits and four posts for wheel hits). A standard sedan with a bumper height of approximately 18 inches while traveling at a speed of 55 ± 2 mph will be used for impact testing. Five of the impacts will be at an ambient temperature of 32 ± 5°F and the remaining five impacts at an ambient temperature of 85 ± 5°F. The test vehicle shall impact four of the posts at an angle perpendicular to the front of the post and shall impact the remaining posts at an angle of 25 degrees clockwise from the angle perpendicular to the front of the posts. The same test samples will be used for the ten hits. Two flexible posts will be used for weatherometer testing. A glancing hit is defined as one on the bumper near the vehicle headlight. The delineators shall be installed a minimum of eight hours prior to being hit.
9-17.3(1) Test Observations
Inspect each post after each impact and document the following:
1.Any splits, cracks, breaks, or other forms of deformation or distress;
2.The percent list to vertical 2 minutes after each impact;
3.The approximate percentage of the reflective area that is damaged after each impact to an extent it no longer performs as intended;
4.Any problems or comments associated with the installation and removal of the posts and bases. The testing agent will document any special equipment or techniques required for installing or removing the posts and bases.
5.Any problems or comments associated with the performance of each ground mounted flexible delineator post that would be of interest to the states;
6.Type of soil and impact surface.
9-17.3(2) Acceptance
A failure is defined as any of the following:
1.A minimum of 50 percent of the reflective sheeting shall be retained undamaged. An area of damage greater than 50 percent is considered a failure.
2.If the guide post leans more than 10 degrees from vertical it is considered a failure.
3.Any cracking, other than surface cracking evident on only one face of the post, is considered a failure.
4.Pullout in excess of 3 inches is considered a failure. At least six of the guide posts must pass each criteria in the 55 ± 2 mph series of impacts to be acceptable.
9-17.4 Pre-approval
In order for a particular model of flexible guide post to become preapproved, the following conditions must be met:
1.The manufacturer must submit a written request for pre-approval along with samples for each model to be tested to: State Materials Engineer, Department of Transportation Materials Laboratory, PO Box 47365, Olympia, WA 98504-7365. Requests shall identify the model for which approval is being requested. Samples shall be complete with reflective panel attached and shall be accompanied by the manufacturer’s written installation procedures.
2.The guide posts will be field impact tested by the State Materials Laboratory to verify compliance with these Specifications. M 41-10 Page 9-119 Flexible Guide Posts 9-173. In lieu of State Materials Laboratory testing, the Lab will accept the results of preapproved testing performed by the National Transportation Product Evaluation Program (NTPEP), the manufacturer, or other agencies under the following conditions:
a.The State Materials Laboratory is informed of the preapproval testing sufficiently in advance in order to attend and observe. Attendance will be at the discretion of the Materials Laboratory.
b.The results of the testing shall be reported in sufficient detail to enable the State Materials Laboratory to evaluate compliance with these Specifications.
4.The manufacturer must submit a certified test report, including test data developed by an approved testing laboratory, which demonstrates that the guide post complies with the requirements of these Specifications. Certified test data supplied by the manufacturer shall be subject to verification by appropriate tests conducted by the State Materials Laboratory. Frequency of field testing, evaluation, and pre-approval updating shall be at the sole discretion of the State Materials Laboratory.
Source: Washington Standard Specifications for Road, Bridge, and Municipal Construction, 2024 Edition. Pages 1026–1029 of 1,151.