"H" Section
A steel member with a cross section in the shape of an "H".
Hair Pin
"V" shaped reinforcing steel used to transfer shear in the anchor rods to the concrete
floor mass.
Hand-Geared (Crane)
A crane in which the bridge, hoist, or trolley is operated by the manual use of chain and
gear without electric power.
Haunch
The deepened portion of a column or rafter designed to accommodate the higher
bending moments at such points. (Usually occurs at the intersection of column and
rafter.)
Haunch Brace
A diagonal member from the intersection of the column and rafter section of the rigid
frame to the eave member to prevent lateral buckling of the haunch.
Header
The horizontal framing member located at the top of a framed opening.
Heating Degree Day (HDD)
The difference in temperature between the outdoor mean temperature over a 24-hour
period and a given base temperature. For example, using a base temperature of 65° F a
day with 50° F mean temperature has 15 HDD (65-50=15). The annual Heating
Degree Days are the sum of the degree days over a calendar year.
Hem
The edge created by folding metal back on itself.
High Strength Bolts
Any bolt made from steel having a tensile strength in excess of 100,000 pounds per
square inch.
High Strength Steel
Structural steel having a yield stress in excess of 36,000 pounds per square inch.
Hinged Base
See "Pinned Base".
Hip
The line formed at the intersection of two adjacent sloping planes of a roof.
Hip Roof
A roof that is formed by sloping planes from all four sides.
Hoist
A mechanical lifting device usually attached to a trolley that travels along a bridge,
monorail or jib crane. May be chain or electric operated.
Horizontal Guide Rollers
Wheels mounted near the ends of end trucks that roll on the side of the rail to restrict
lateral movement of the crane.
Hot-Rolled Shapes
Steel sections (angles, channels, S-shapes, W-shapes, etc.) which are formed by rolling
mills while the steel is in a semi-molten state.
Hydrokinetic
Metal panel systems that are designed to “shed water” are referred to as hydrokinetic.
Hydrokinetic roof details are typically devoid of sealant and rely on water to freely
shed over the joints. Hydrokinetic roof details are not to be used on roof slopes below
3:12.
Hydrostatic
Metal panel systems that are designed to withstand being submersed in water for a
period of time are called hydrostatic panels. Hydrostatic roof details rely on sealant to
keep water from infiltrating the joints and seams. Hydrostatic roof details can be used
at almost any roof slope (1/4:12 minimum).