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BRIDGE TERMS - H |
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hairline
cracks |
hairline cracks - very small cracks that form in the surface of concrete due to tension caused by loading hammer - hand tool used for pounding and surface inspection hammerhead pier - a pier with a single cylindrical or rectangular shaft and a relatively long, transverse cap; also known as a tee pier hand hole - holes provided in cover plates of built-up box sections to permit access to the interior for maintenance and construction purposes hand rail - commonly applies only to sidewalk railing presenting a latticed, barred, balustered or other open web construction hands on access - close enough to the member or component so that it can be touched with the hands hanger - a tension member serving to suspend an attached member haunch - an increase in the depth of a member usually at points of support; the outside areas of a pipe between the spring line and the bottom of the pipe H-beam - a rolled steel member having an H-shaped cross section and commonly used for piling; also H-pile head - a measure of water pressure expressed in terms of an equivalent weight or pressure exerted by a column of water; the height of the equivalent column of water is the head headloss - the loss of energy between two points along the path of a flowing fluid due to fluid friction reported in feet of head headwall - a concrete structure at the ends of a culvert to protect the embankment slopes, anchor the culvert, and prevent undercutting headwater - the source or the upstream waters of a stream heat treatment - any of a number of various operations involving heating and cooling that are used to impart specific properties to metals; examples are tempering, quenching, annealing, etc. helical - having the form of a spiral high carbon steel - carbon steel containing 0.5 to 1.5% dissolved carbon high strength bolt - bolt and nut made of high strength steel, usually A325 or stronger hinge - a point in a structure at which a member is free to rotate hinged joint - a joint constructed with a pin, cylinder segment, spherical segment or other device permitting movement by rotation hip joint - the juncture of the inclined end post with the end top chord member of a truss; also known as the hip truss hip vertical - the vertically placed tension member engaging the hip joint of a truss and supporting the first panel floor beam in a through truss span, or instead, only the bottom chord in a deck truss span honeycomb - an area in concrete with a lack of mortar to fill in the spaces between the coarse aggregate horizontal cracks - cracks which are parallel to the longitudinal axis of the member and thus parallel to the primary stress horizontal curve - a curve in the plan location defining the alignment Howe truss - a truss of the parallel chord type with a web system composed of vertical (tension) rods at the panel points with an X pattern of diagonals hydraulics - the mechanics of fluids, primarily water hydrology - the science of water related to its properties and distribution in the atmosphere, on the land surface, and beneath the surface of the land hydroplaning - loss of contact between a tire and the deck surface when the tire planes or glides on a film of water covering the deck |
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