GUARDRAILS

GUARDRAILS

Post 388 ⇒   by Gautam Shah 

.

Guardrails are, both, protective barriers and rails for guidance. These are placed against a drop in terrain (of more than 750mm), against the edges of exclusive passage, or rights of ways. Guardrails, mark a visually recognizable guide line. Such guide lines are recognizable in inclement weather (heavy rains, fog, smog and darkness). A guard rail often is designed to bear heavier impact of side thrusts in comparison to a hand rail. A hand rail, as per most of the building standards cannot have a gap larger than 100 mm, whereas for Guardrails can have a gap slightly smaller than the front wheel dia of the vehicles, or at least 220mm.

640px-interstate_70_through_colorado_mountains

Interstate Highway through Colorado > Wikipedia image by Retaildesigner

 Guardrails are placed in buildings, terrains and roads. Many of the edge side structures such as, hand rails, parapets or fences can be called guard rails. Guardrails are both man-made structures or contoured natural features. Guardrails on any type of passage ways should be minimal. Modern roads are designed in a manner to eliminate the need for a guard rail. These means include provisions of apron spaces, contoured ends and landscaped features to indicate presence of zones of dangers. Road barricades work as guardrails. Many are installed as temporary (demountable) or permanent structures to prevent surprise or forced entry of terrorists or demonstrators.

640px-kaluga_region_trassa

Kaluga region Trassa Road side barricade > Wikipedia image by Denghu at English Wikipedia

640px-jeresy_barriers_against_terror_attacks2c_acre2c_israel

Jeresy type barriers against car attacks in Israel  >Wikipedia image by Netanel h

4732382969_364b4e8797_z

Protective Road Guardrails or barricades -folding and lightweight by Police > Flickr image by Indi Samarajiva

 

Guardrails are essentially of two types: 1. Rigid ones bear an impact to an extent, but mainly help bounce back of the object in certain direction, and possibly retard the movement of the object; 2. Flexible ones bear the impact substantially within the body and yet redirect the object to a safer zone. In both the cases an objective is to keep the vehicle upright while being deflected along the guardrail.

640px-hk_lantau_island_e6aca3e6beb3e98193_sunny_bay_road_20070616-11_highway_bridge

Lantau Island Sunny Bay Road HK > Wikipedia image by Summa06

 Road guardrails are designed with the roads or installed as retrofit when certain sections show such a need. Former types of guardrails are fairly long whereas the later types are zone-specific and comparatively shorter. Specific types of guide rails are placed to prevent accidents due to the road elements or fixed objects. These elements include bridge supports, piers, road signages, culverts, trees, etc.

640px-police_22response22_to_pad_protest

Live Guards forming a Rail for crowd control > Wikipedia image by Craig Martell

 Guardrails on roads and other sites have the inner edge (use or the movement side face) completely free of obstructions. The rails are so constructed that they form a continuous visual and functional surface. The joints formed with a backing element rather than by lapping. The colour and surface texture are consistent.

640px-the_kop_saltergate_chesterfield_fc

Crowd anti stampede Guards at Saltergate > Wikipedia image by Jaxban 

 Guardrails function as an integrated system where the guardrail, posts, post foundation structure and support braces, all share the impact load. In spite of a rigid design, guardrails do deflect. The amount of deflection depends on such factors as: straight or curved formation of the guardrail layout, height of the guardrail, shape or section of the rail, direction of the impact (parallel, head-on, angular), weight of impacting objects (mass-inertia), height of the impacting object, nature of support posts, and distance between the supports.

640px-niagara_falls_-_on_-_skylon_tower_28aussichtsdeck29

Guardrails for Niagara Falls > Wikipedia image by Wladyslaw

Road and other guard rails are universal structures, serving variety of vehicles (cars, trucks, motorcycles, cycles), people (adults, infirm, children, rowdy crowds), climatic conditions (rains, fog, smog, snow), and varying terrain conditions (floods, landslides, dumping, oil leaks). An optimum height for a car may not prevent a truck from toppling over the rail and a motorbike or human being sliding under it.

bollard-1342307_640

Barricade Bollards > Pixabay free images by serghei_topor Enter a caption

.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s